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Background Nuclear protein transport is essential in guiding the traffic of important proteins and RNAs between the nucleus and cytoplasm. Export of proteins from the nucleus is mostly regulated by Exportin 1 (XPO1). In cancer, XPO1 is almost universally hyperactive and can promote the export of important tumor suppressors to the cytoplasm. Currently, there are no studies evaluating XPO1 amplifications and mutations in NSCLC and the impact on outcomes. Methods Tumor samples were analyzed using next-generation sequencing (NGS) (NextSeq, 592 Genes), immunohistochemistry (IHC), and whole transcriptome sequencing (WTS, NovaSeq) (Caris Life Sciences, Phoenix, AZ). Survival was extracted from insurance claims data and calculated from time of tissue collection to last contact using Kaplan-Meier estimate. Results Among 18,218 NSCLC tumors sequenced, 26 harbored XPO1 mutations and 24 had amplifications. XPO1 mutant tumors were more likely to have high TMB (79% vs. 52%, p = 0.007) and less likely to have high PD-L1 (32% vs. 68%, p = 0.03). KRAS co-mutations were seen in 19% (n = 5) and EGFR co-mutations were rare (n = 2). Among the 17,449 NSCLC tumors with clinical data, there were 24 XPO1 mutant. Comparison of survival between XPO1 mutant and WT showed a negative association with a hazard ratio (HR) of 1.932 (95% CI: 1.144–3.264 p = 0.012). XPO1 amplification was not associated with survival. Conclusions XPO1 pathogenic mutations were associated with a poor survival in NSCLC. Although XPO1 mutations are rare in NSCLC, further studies to assess its associations with treatment responses are warranted.

Exportin 1 (XPO1), also known as chromosome region maintenance protein 1, plays a crucial role in maintaining cellular homeostasis via the regulated export of a range of cargoes, including proteins and several classes of RNAs, from the nucleus to the cytoplasm. Dysregulation of this protein plays a pivotal role in the development of various solid and haematological malignancies. Furthermore, XPO1 is associated with resistance to several standard-of-care therapies, including chemotherapies and targeted therapies, making it an attractive target of novel cancer therapies. Over the years, a number of selective inhibitors of nuclear export have been developed. However, only selinexor has been clinically validated. The novel mechanism of action of XPO1 inhibitors implies a different toxicity profile to that of other agents and has proved challenging in certain settings. Nonetheless, data from clinical trials have led to the approval of the XPO1 inhibitor selinexor (plus dexamethasone) as a fifth-line therapy for patients with multiple myeloma and as a monotherapy for patients with relapsed and/or refractory diffuse large B cell lymphoma. In this Review, we summarize the progress and challenges in the development of nuclear export inhibitors and discuss the potential of emerging combination therapies and biomarkers of response.

Pancreatic neuroendocrine tumors (PNETs) are known to be the second most common epithelial malignancy of the pancreas. PNETs can be listed among the slowest growing as well as the fastest growing human cancers. The prevalence of PNETs is deceptively low; however, its incidence has significantly increased over the past decades. According to the American Cancer Society’s estimate, about 4032 (> 7% of all pancreatic malignancies) individuals will be diagnosed with PNETs in 2020. PNETs often cause severe morbidity due to excessive secretion of hormones (such as serotonin) and/or overall tumor mass. Patients can live for many years (except for those patients with poorly differentiated G3 neuroendocrine tumors); thus, the prevalence of the tumors that is the number of patients actually dealing with the disease at any given time is fairly high because the survival is much longer than pancreatic ductal adenocarcinoma. Due to significant heterogeneity, the management of PNETs is very complex and remains an unmet clinical challenge. In terms of research studies, modest improvements have been made over the past decades in the identification of potential oncogenic drivers in order to enhance the quality of life and increase survival for this growing population of patients. Unfortunately, the majority of systematic therapies approved for the management of advanced stage PNETs lack objective response or at most result in modest benefits in survival. In this review, we aim to discuss the broad challenges associated with the management and the study of PNETs.

Aberrant nuclear protein transport, often observed in cancer, causes mislocalization dependent inactivation of critical cellular proteins. Earlier we showed that over-expression of the nuclear export protein exportin 1 (XPO1) is linked to higher grade and Gleason score in metastatic castration resistant prostate cancer (mCRPC). We also showed that the selective inhibitor of nuclear export (SINE) compound selinexor and the second generation SINE eltanexor (KPT-8602) could suppress mCRPC growth, reduce androgen receptor (AR), and re-sensitize to androgen deprivation therapy. Here we evaluated the combination of KPT-8602 with three different PARP inhibitors (PARPi) namely olaparib, veliparib and rucaparib in a mCRPC model. Growth inhibition was determined by MTT assay. Drug synergy analysis was done and the isobolograms were generated from Calcusyn 2.1 software (Biosoft, Cambridge, UK). Other techniques include: colony formation assay, apoptosis determination by flow cytometry (annexin V-propidium iodide), real time RT-qPCR (SYBR green I), western blotting, immunofluorescence etc. For the determination of band density, NIH ImageJ 1.5Oi software was utilized. KPT-8602 synergized with all three studied PARPi (CI Taken together, this study revealed the therapeutic potential of a novel combination including second generation SINE compound KPT-8602 and PARP inhibitors for the growth inhibition of mCRPC cells. Pre-clinical xenograft studies testing the efficacy of SINE-PARPi as well as a phase II clinical study combining KPT-8602-PARPi is planned. Citation Format: Md. Hafiz Uddin, Yiwei Li, Amro Aboukameel, Husain Y. Khan, Vijendra Singh, Shriya Reddy, Suresh Kumar Balasubramanian, Yosef Landesman, Trinayan Kashyap, Elisabeth I. Heath, Asfar S. Azmi. Nuclear export inhibitor KPT-8602 synergize with PARP inhibitors in castration resistant metastatic prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1091.

It has been almost two decades since the first link between microRNAs and cancer was established. In the ensuing years, this abundant class of short noncoding regulatory RNAs has been studied in virtually all cancer types. This tremendously large body of research has generated innovative technological advances for detection of microRNAs in tissue and bodily fluids, identified the diagnostic, prognostic, and/or predictive value of individual microRNAs or microRNA signatures as potential biomarkers for patient management, shed light on regulatory mechanisms of RNA–RNA interactions that modulate gene expression, uncovered cell‐autonomous and cell‐to‐cell communication roles of specific microRNAs, and developed a battery of viral and nonviral delivery approaches for therapeutic intervention. Despite these intense and prolific research efforts in preclinical and clinical settings, there are a limited number of microRNA‐based applications that have been incorporated into clinical practice. We review recent literature and ongoing clinical trials that highlight most promising approaches and standing challenges to translate these findings into viable microRNA‐based clinical tools for cancer medicine. This article is categorized under:RNA in Disease and Development > RNA in Disease, microRNAs are short noncoding regulatory RNAs with important roles in cancer biology. microRNAs are informative biomarkers for early cancer detection and treatment decisions. microRNAs are being evaluated in clinical trials as new drugs for personalized cancer medicine.

Colorectal cancer (CRC) is a leading cause of cancer related deaths worldwide and the third leading cause of cancer related deaths in the United States with a 5-year survival rate of 63%. Depending on the stage of disease, there are differing rates of overall survival: Stage I (90%) vs. Stage IV (14%). There is a clear discrepancy between early and late stage disease due to a variety of factors including acquired genetic and tumor mutations and lack of initial symptoms leading to late stage detection. It is clear that further understanding into the mechanisms of CRC need to be explored in depth to improve overall survival rates. ATP binding cassette subfamily B member 5 (ABCB5) has been found to be pathogenic in a variety of diseases including melanoma and colorectal cancer but there has been few studies looking at the cellular consequences of ABCB5 upregulation in CRC cells. Using publicly accessible databases, we explored ABCB5 positivity in CRC cells and found novel interactions with 64 differentially expressed genes involved in cellular processes like modulation of inflammation, (XCL1, TNFSF4), enhanced cell signaling via interaction with serine protease inhibitors (SERPINB4, WFDC6) and downregulation of anti-apoptotic proteins (SPIN2A). Although ABCB5 upregulation is not currently targetable with pre-clinical compounds, our analysis revealed the genetic effects induced by ABCB5 upregulation are targetable, including evidence of sensitivity to the XPO1 inhibitor XPOVIO (selinexor). It is clear further pre-clinical investigation is needed to validate these findings.

Gastric cancer remains a major unmet clinical problem with over 1 million new cases in 2018 worldwide. It is the fourth most commonly occurring cancer in men and the seventh most commonly occurring cancer in women. A major fraction of gastric cancer has been linked to variety of pathogenic infections including but not limited to Helicobacter pylori (H. pylori) or Epstein Barr virus (EBV). Strategies are being pursued to prevent gastric cancer development such as H. pylori eradication, which has helped to prevent significant proportion of gastric cancer. Today, treatments have helped to manage this disease and the 5-year survival for stage IA and IB tumors treated with surgery are between 60% and 80%. However, patients with stage III tumors undergoing surgery have a dismal 5-year survival rate between 18% and 50% depending on the dataset. These figures indicate the need for more effective molecularly driven treatment strategies. This review discusses the molecular profile of gastric tumors, the success and challenges with available therapeutic targets along with newer biomarkers and emerging targets.

Novel treatment strategies for pancreatic ductal adenocarcinoma (PDAC) are desperately needed. Local tumor progression is a cause of significant morbidity and mortality in patients with surgically unresectable disease. Often, regional anatomic structures limit the total doses of radiation therapy (RT) that can be safely delivered. Conventional doses of concurrent chemotherapy and RT (chemo-RT) have shown suboptimal results in local control of disease, progression free survival, and overall survival. Therefore, novel and effective approaches to enhance the efficacy of RT are urgently needed to improve overall survival in unresectable PDAC. Metabolic reprogramming enables cancer cells to adjust their metabolism to support increased energy requirements associated with continuous growth and proliferation. Indeed, metabolic reprogramming is a hallmark of PDAC and is associated with increased tumor cell plasticity and chemo-RT resistance. Cancer-cell mitochondria are key regulators of deranged tumor metabolism and have been shown to guide molecular pathways involved in radio-resistance. There is also expanding data that the presence of metabolites modulates the response of cancer cells to RT primarily by impacting the ability to repair DNA. This makes them an optimal candidate for novel radiosensitization strategies, as these characteristics are unique to PDAC cells, and are limited in normal cells. CPI-613, is an analog of lipoic acid which inhibits pyruvate dehydrogenase (PDH) and α-ketoglutarate dehydrogenase (α-KGDH), thereby disrupting mitochondrial metabolism leading to selective tumor cell killing. The drug has demonstrated significant clinical activity in patients with metastatic PDAC in combination with standard of care chemotherapies. It remains unknown as to the efficacy in patients treated with concurrent chemo-RT. Here we show that combined treatment of RT (2 and 10 Gy) with CPI-613 (used at 200 and 300 μM) causes superior inhibition of pancreatic cancer cell growth (MTT assay and colony formation assay). In addition, we demonstrate enhanced apoptosis (Annexin V FITC and 7AAD assay) of PDAC cells when treated with a combination of RT and CPI-613. Molecular analysis revealed superior inhibition of PDH and α-KGDH at the protein level. Targeted metabolomic analysis on PDAC cells post CPI-613-RT treatment revealed alterations in key mitochondrial metabolites, leading to these findings. These results indicate broader target engagement by this combination treatment, indicating the sensitization of CPI-613 treated PDAC cells to radiotherapy at doses as low as 2 Gy. Furthermore, in our preclinical cellular models, a combination treatment of CPI-613 with either Gemcitabine or 5-FU has shown synergistic effects on the proliferation of PDAC cells. Pre-clinical anti-tumor efficacy of the CPI-613-RT and CPI-613-RT-chemo using subcutaneous and orthotopic PDAC models is planned. Our results bring forward a novel combination of CPI-613-RT that warrants further pre-clinical and early phase clinical investigations. Citation Format: William A. Hall, Husain Y. Khan, Mandana Kamgar, Susan Tsai, Kathleen Christians, Douglas B. Evans, Philip Philip, Callisia Clarke, Ben George, Beth Erickson, Asfar S. Azmi. Targeting cellular metabolism with CPI-613 sensitizes pancreatic cancer cells to radiotherapy [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-024.

Mutations in Kirsten rat sarcoma viral oncogene homolog (KRAS) are among the most common aberrations in cancer, including non-small cell lung cancer (NSCLC). The lack of an ideal small molecule binding pocket in KRAS protein and its high affinity towards the abundance of cellular guanosine triphosphate (GTP) renders the design of specific small molecule drugs challenging. Despite efforts, KRAS remains a challenging therapeutic target. Among the different known mutations; the KRAS(G12C) (glycine 12 to cysteine) mutation has been considered potentially druggable. Several novel covalent direct inhibitors targeting KRAS(G12C) with similar covalent binding mechanisms are now in clinical trials. Both AMG 510 from Amgen and MRTX849 from Mirati Therapeutics covalently binds to KRAS(G12C) at the cysteine at residue 12, keeping KRAS(G12C) in its inactive GDP-bound state and inhibiting KRAS-dependent signaling. Both inhibitors are being studied as single agent or as combination with immunotherapy phase 2 trials. In addition, two novel KRAS G12C inhibitors JNJ-74699157 and LY3499446 will have entered phase 1 studies by the end of 2019. Given the rapid clinical development of 4 direct covalent KRAS G12C inhibitors within a short period of time, understanding the similarities and differences among these will be important to determine the best treatment option based on tumor specific response (NSCLC versus colorectal carcinoma), potential resistance mechanisms (i.e. anticipated acquired mutation at the cysteine 12 residue) and central nervous system (CNS) activity. Additionally, further investigation evaluating the efficacy and safety of combination therapies with agents such as immune checkpoint inhibitors will be important next steps.

The disease-preventive benefits of many natural agents, particularly dietary compounds, have been attributed to their well-recognized activity as regulators of the redox state of the cell. Nevertheless, most of these studies have focused on their antioxidant activity. A large body of evidence indicates that several of these agents can elicit prooxidant behavior that has been linked to their anticancer effects. More than a decade ago, our team demonstrated the prooxidant anticancer effects of several such natural compounds. We proposed that dietary natural products, particularly plant-derived polyphenolic compounds, can take advantage of the elevated copper levels in the tumor microenvironment and promote reactive oxygen species generation, leading to cancer cell-selective DNA damage. Over the last decade, we have proven this hypothesis in cell-free, cellular, and animal tumor models. Our studies highlight an important yet underappreciated role of natural dietary compounds as prooxidants that can have therapeutic significance.

INTRODUCTION: The Ca2+release-activated Ca2+ (CRAC) channel, composed of Orai and STIM proteins, represents one of the main routes of Ca(2+) entry in most non-excitable cells. There is accumulating evidence to suggest that CRAC channel can influence various processes associated with tumorigenesis. Overexpression of CRAC channel proteins has been observed in several types of cancer tissues and cells, indicating that blocking CRAC channel activated Ca(2+) influx can have therapeutic benefits for cancer patients. AREAS COVERED: In this review, we have primarily focused on the molecular composition and activation mechanism of CRAC channel as well as the myriad roles this Ca(2+) channel play in various cancers. We further describe relevant information about several efforts aimed at developing CRAC channel blockers and their likely implications for cancer therapy. We have extensively utilized the available literature on PubMed to this end. EXPERT OPINION: The possibility of targeting CRAC channel mediated Ca(2+) entry in cancer cells has generated considerable interest in recent years. Use of CRAC channel blockers in cancer preclinical studies and clinical trials has been relatively limited as compared to other diseases. The future lies in developing and testing more potent and selective drugs that target cancer cell specific CRAC channel proteins, hence opening better avenues for cancer therapeutic development.

Gastric cancer remains an unmet clinical problem in urgent need of newer and effective treatments. Here we show that the nuclear export protein, Exportin 1 (XPO1, chromosome region maintenance 1 or CRM1), is a promising molecular target in gastric cancer. We demonstrate significant overexpression of XPO1 in a cohort of histologically diverse gastric cancer patients with primary and metastatic disease. XPO1 RNA interference suppressed gastric cancer cell growth. Anti-tumor activity was observed with specific inhibitor of nuclear export (SINE) compounds (selinexor/XPOVIO), second-generation compound KPT-8602/eltanexor, KPT-185 and +ve control Leptomycin B in three distinct gastric cancer cell lines. SINE compounds inhibited gastric cancer cell proliferation, disrupted spheroid formation, induced apoptosis and halted cell cycle progression at the G1/S phase. Anti-tumor activity was concurrent with nuclear retention of tumor suppressor proteins and inhibition of colony formation. In combination studies, SINE compounds enhanced the efficacy of nab-paclitaxel in vitro and in vivo. More significantly, using non-coding RNA sequencing studies, we demonstrate for the first time that SINE compounds can alter the expression of non-coding RNAs (microRNAs and piwiRNAs). SINE treatment caused statistically significant downregulation of oncogenic miR-33b-3p in two distinct cell lines. These studies demonstrate the therapeutic significance of XPO1 in gastric cancer that warrants further clinical investigation.

The global incidence of gastric cancer exceeds 1 million people per year and has a 5-year survival rate of 31%. Current chemotherapies are not effective because of genetic and epigenetic heterogeneity and late stage detection. Previously, we showed that exportin 1 (XPO1) is a therapeutic target in gastric cancer, as it facilitates the nuclear export of various cancer related tumor suppressor proteins (TSPs) through direct interaction with their nuclear export sequences (NES). XPO1 is upregulated in a variety of tumors including gastric cancer, leading to increased cytoplasmic localization of TSPs supporting malignant transformation and cancer cell proliferation, Knockdown of XPO1 leads to anti-tumor effects and pharmacologic targeting of XPO1 is achievable with selective inhibitors of nuclear export (SINE) compounds. In 2019 and 2020, the first generation XPO1 inhibitor KPT-330 was FDA approved for the use in penta-refractory multiple myeloma and non-Hodgkin's Lymphoma. Besides protein, mRNA and non-coding RNAs are also transported across the nuclear membrane. Non-coding RNA transport is generally attributed to another nuclear export protein, exportin 5 (XPO5), which plays a critical role in microRNA (miRNA) biogenesis. Nevertheless, there is emerging evidence supporting the role of XPO1 in non-coding RNA transport. In order to elucidate the role of XPO1 in non-coding RNA biology, we performed small RNA sequencing on gastric cancer cell lines treated with the XPO1 inhibitor selinexor. Our results revealed statistically significant changes in miR-7974 and miR-129-1-3p. These two miRs are recognized to influence protein modifications and cell survival. Administration of a miR-7974 mimic and a miR-129-1-3p inhibitor reduced proliferation of gastric cancer cells. Next, we evaluated the miR target genes of interest. At the mRNA level, we found upregulation of RasGEF Domain Family Member 1a (RASGEF1A), downregulation of DNA damage-regulated autophagy modulator 1 (DRAM1), downregulation of TIMP2 and downregulation of Cyclin G2 protein encoding gene CCNG2. Western Blots confirmed inhibition of AKT, RAS and Wnt signaling. Our results also showed that miR-7974 overexpression correlated with cellular XPO1 levels through the enhancement of XPO1 and its cargoes RCC1 and RANBP2. Finally inhibition of XPO1 by SINE compounds reversed the observed oncogenic phenotypes caused by these microRNAs. Our results unveil a novel interaction network between XPO1 and small non-coding RNAs and show that XPO1 induced small-noncoding microRNAs influence gastric cancer proliferation, and can be reversed by SINE compounds. This implies that modulation of microRNAs might be explored as a biomarker for XPO1 inhibitor therapy and warrants further investigation. Citation Format: Rachel E. Sexton, Mohammad Najeeb Al-Hallak, Bayan Al-Share, Yiwei Li, Amro Aboukameel, Yosef Landesman, Trinayan Kashyap, Steve Kim, Ramzi M. Mohammad, Philip A. Philip, Asfar S. Azmi. Mir-7974: An oncogenic miRNA that perpetuates gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2383.

The p21-activated kinase 4 (PAK4) is a key downstream effector of the Rho family GTPases and is found to be overexpressed in pancreatic ductal adenocarcinoma (PDAC) cells but not in normal human pancreatic ductal epithelia (HPDE). Gene copy number amplification studies in PDAC patient cohorts confirmed PAK4 amplification making it an attractive therapeutic target in PDAC. We investigated the antitumor activity of novel PAK4 allosteric modulators (PAM) on a panel of PDAC cell lines and chemotherapy-resistant flow-sorted PDAC cancer stem cells (CSC). The toxicity and efficacy of PAMs were evaluated in multiple subcutaneous mouse models of PDAC. PAMs (KPT-7523, KPT-7189, KPT-8752, KPT-9307, and KPT-9274) show antiproliferative activity in vitro against different PDAC cell lines while sparing normal HPDE. Cell growth inhibition was concurrent with apoptosis induction and suppression of colony formation in PDAC. PAMs inhibited proliferation and antiapoptotic signals downstream of PAK4. Co-immunoprecipitation experiments showed disruption of PAK4 complexes containing vimentin. PAMs disrupted CSC spheroid formation through suppression of PAK4. Moreover, PAMs synergize with gemcitabine and oxaliplatin in vitro. KPT-9274, currently in a phase I clinical trial (clinicaltrials.gov; NCT02702492), possesses desirable pharmacokinetic properties and is well tolerated in mice with the absence of any signs of toxicity when 200 mg/kg daily is administered either intravenously or orally. KPT-9274 as a single agent showed remarkable antitumor activity in subcutaneous xenograft models of PDAC cell lines and CSCs. These proof-of-concept studies demonstrated the antiproliferative effects of novel PAMs in PDAC and warrant further clinical investigations. Mol Cancer Ther; 16(1); 76–87. ©2016 AACR.

Development of acquired resistance to cisplatin (CDDP) is a major obstacle in the treatment of ovarian cancer patients. According to the cancer stem cell (CSC) hypothesis, the recurrence and chemoresistance are presumed to be linked to cancer stem/progenitor cells. Here, we investigated the CSC-like phenotypes and mechanism of chemoresistance in CDDP resistant ovarian cancer cells. A well-established CDDP sensitive ovarian cancer cell line A2780 and its resistant population A2780-Cp were used. We also developed a supra resistant population (SKOV3-Cp) from a naturally CDDP resistant cell line SKOV3. Both resistant/supra resistant cell lines showed significantly higher self-renewal capability than their parental counterparts. They also showed significant resistance to apoptosis and sub-G1 arrest by CDDP treatment. Stem cell marker ALDH1 positivity rates were higher both in A2780-Cp and SKOV3-Cp cell lines than in their counterparts, quantified by Aldefluor assay kit. Hoechst 33342 dye effluxing side populations were increased up to about five folds in A2780-Cp cells and two folds in SKOV3-Cp cells compared to A2780 and SKOV3 cells, respectively. Among major stemness related genes (POU5F1/OCT4, SOX2, NANOG, NES, BMI1, KLF4 and ALDH1A1), ALDH1A1 and KLF4 were significantly overexpressed in both resistant/supra resistant cells. Silencing ALDH1A1 in A2780 and A2780-Cp cells using siRNA greatly reduced the stem cell population and sensitized cells to CDDP. Moreover, silencing of ALDH1A1 reduced the transcript and protein level of its downstream target NEK-2. We also observed the downregulation of ABC transporters (ABCB1/MDR1, ABCG2 and ABCC1/MRP1) either by ALDH1A1 or NEK-2 silencing and upreguation of ABCB1/MDR1 due to the overexpression of NEK-2. Taken together, the present study suggests that stemness gene ALDH1A1 can be involved in CDDP resistance through the upregulation of NEK-2 in ovarian cancer., Cell biology; Cell culture; Cell death; Molecular biology; Cancer research; Cisplatin resistance; Ovarian cancer; ALDH1A1; NEK-2; ABC transporters; Stemness.

Background: Dihydroorotate dehydrogenase (DHODH) is an enzyme which is critically involved in process of de novo pyrimidine biosynthesis. Therefore, it plays important roles in cell proliferation, mitosis and cellular metabolism. Importantly, overexpression of DHODH has been found in various types of malignant tumors including melanoma, myeloma, and lymphoma. Moreover, from Oncomine database, we observed that colorectal and kidney cancers and lymphoma have much higher expression of DHODH compared to normal cells. These findings suggest that DHODH could be a promising target for cancer therapy. Recently, we have designed and synthesized a novel small molecule inhibitor (RP7214) of DHODH and found that it has potent inhibitory effects in acute myeloid leukemia. However, the inhibitory effect of RP7214 on solid tumor-derived cell lines and the downstream oncogenic markers is not completely understood. Methods: In vitro studies aimed at elucidating the effects of RP7214 on cell proliferation and the underlying molecular mechanisms were conducted using breast adenocarcinoma (MDA-MB-231) and colorectal carcinoma cell lines (HT-29 and HCT-116). We also investigated whether RP7214 could potentiate the anti-cancer activities of proven chemotherapeutics such as Verzenio, Doxorubicin, and Oxaliplatin, for the treatment of breast and colorectal cancers. Results: RP7214 significantly (P Conclusions: Based on these results, we conclude that RP7214 could be a promising DHODH inhibitor used in combination with conventional chemotherapeutics for better treatment of breast and colorectal cancers. We are now conducting animal experiment to confirm the value of RP7214 in vivo in combination treatment of breast and colorectal cancers. Citation Format: Asfar S. Azmi, Amro Aboukameel, Mohammad Najeeb Al-Hallak, Philip A. Philip, Kumar Penmetsa, Srikant Visvanadha, Gabriel Mpilla, Rachel Sexton, Ramzi M. Mohammad. A novel, small molecule inhibitor of dihydroorotate dehydrogenase (DHODH), RP7214, potentiates activity of chemotherapeutics in breast and colorectal cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 234.

Pancreatic ductal adenocarcinoma (PDAC) is the third-highest cause of cancer-related death in the United States. The heterogenicity of the PDAC is a major challenge in the success of anti-PDAC therapy. PDAC is comprised of >90 % dense desmoplastic tumor stroma that impedes the delivery of drugs into the core of the tumor, resulting development of drug resistance. Thus, we developed a nanoparticle pro-drug to overcome the stromal barrier of PDAC. We utilized nanoengineering to target dual CD44 and c-Met biomarkers that have a significant role in developing drug resistance on PDAC. Western blot analysis in various PDAC cell lines, such as PANC-1, AsPc-1, and BxPc3 revealed a high abundance of CD44 and cMet, strongly supporting our hypothesis. Therefore, targeting the CD44 and c-Met biomarker and selectively delivering anti-PDAC drug is a smart strategy to improve the anti-PDAC outcome. We developed dual CD44/c-Met targeted nanoparticle, called D44M that can efficiently penetrate the core of tumor as well as home into CD44 and cMet biomarker. We evaluated tumor selectivity of the near infrared (NIR) fluorescent dye conjugated D44M, D44M-NIR in the orthotopic PDAC model. The biodistribution of D44M-NIR in orthotopic animal model proved superior tumor penetration of D44M-NIR with 7-fold higher than the control NIR dye treatment. Moreover, D44M-NIR treated showed minimum liver accumulation, suggesting an outstanding approach of overcoming nanoparticle mediated liver toxicity. Finally, the D44M was chemically conjugated with gemcitabine (GEM), namely D44M-GEM pro-drug that showed excellent PDAC killing. The PDAC cell killing study of D44M-GEM in combination with Everolimus revealed high synergistic combination effect with CI value of 0.2-0.5. The anti-PDAC therapy in ASPC-1 xenograft model demonstrated significant tumor growth inhibition for treatment of D44M-GEM and D44M-GEM+Everolimus as compared to control. Supported with data, our work provides a perspective towards the implementation of nanotherapeutic to overcome the bottleneck barrier of therapeutic delivery and efficacy of PDAC management. Citation Format: Rami Alzhrani, Samaresh Sau, Amro Aboukameel, Hashem Alsaab, Asfar Azmi, Arun Iyer. Nanoparticle pro-drug to overcome the stromal barrier in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1722.

Pancreatic ductal adenocarcinoma (PDAC) remains the fourth leading cause of cancer-related death in the United States. Since the hallmark clinical trial in 1997 that showed superiority of gemcitabine over 5-fluorouracil, gemcitabine has been the mainstay of treatment of PDAC, either as single agent or in combination with other treatments. FOLFIRINOX (folinic acid, fluorouracil, irinotecan, and oxaliplatin) was also recently introduced for the treatment of patients with a good performance status. However, despite large cancer sequencing initiatives in the past decade that have allowed for a better understanding of the molecular biology of PDAC, highly efficacious therapies, especially in the setting of locally advanced and metastatic disease, are still lacking. Although several target agents have been investigated in PDAC, almost all have failed to demonstrate a survival benefit in late-phase clinical trials. In this chapter, we will review novel target agents that were evaluated in clinical trials for the treatment of PDAC, focusing on small-molecule therapies.

Pancreatic cancer is a deadly disease that is resistant to most available therapeutics. Pancreatic cancer to date has no effective drugs that could enhance the survival of patients once their disease has metastasized. There is a need for the identification of novel actionable drug targets in this unusually recalcitrant cancer. Nuclear protein transport is an important mechanism that regulates the function of several tumor suppressor proteins (TSPs) in a compartmentalization-dependent manner. High expression of the nuclear exporter chromosome maintenance region 1 (CRM1) or exportin 1 (XPO1), a common feature of several cancers including pancreatic cancer, results in excessive export of critical TSPs to the incorrect cellular compartment, leading to their functional inactivation. Small molecule inhibitors of XPO1 can block this export, retaining very important and functional TSPs in the nucleus and leading to the effective killing of the cancer cells. This review highlights the current knowledge on the role of XPO1 in pancreatic cancer and how this serves as a unique and clinically viable target in this devastating and by far incurable cancer.

INTRODUCTION:Sustained proliferative signaling and de-regulated cellular bioenergetics are two of the chief hallmarks of cancer. Alterations in the Ras pathway and its downstream effectors are among the major drivers for uncontrolled cell growth in many cancers. The GTPases are one of the signaling molecules that activate crucial signal transducing pathways downstream of Ras through several effector proteins. The GTPases (GTP bound) interact with several effectors and modulate a number of different biological pathways including those that regulate cytoskeleton, cellular motility, cytokinesis, proliferation, apoptosis, transcription and nuclear signaling. Similarly, the altered glycolytic pathway, the so-called 'Warburg effect', rewires tumor cell metabolism to support the biosynthetic requirements of uncontrolled proliferation. There exists strong evidence for the critical role of the glycolytic pathway's rate limiting enzymes in promoting immunosuppression. Areas covered: We review the emerging roles of GTPase effector proteins particularly the p21 activated kinase 4 (PAK4) and nicotinamide biosynthetic pathway enzyme nicotinamide phosphoribosyltransferase (NAMPT) as signaling molecules in immune surveillance and the immune response. Expert opinion: In this expert opinion article we highlight the recent information on the role of GTPases and the metabolic enzymes on the immune microenvironment and propose some unique immune therapeutic opportunities.

Pancreatic ductal adenocarcinoma (PDAC) is projected to be the second leading cause of cancer related mortality in the United States in 2030, with a 5-year overall survival of less than 10% despite decades of extensive research. Pancreatic cancer is marked by the accumulation of complex molecular changes, complex tumor-stroma interaction, and an immunosuppressive tumor microenvironment. PDAC has proven to be resistant to many cytotoxic, targeted and immunologic treatment approaches. Areas covered: In this paper, we review the major areas of research in PDAC, with highlights on the challenges and areas of opportunity for personalized treatment approaches. Expert commentary: The focus of research in pancreatic cancer has moved away from developing conventional cytotoxic combinations. The marked advances in understanding the molecular biology of this disease especially in the areas of the microenvironment, metabolism, and DNA repair have opened new opportunities for developing novel treatment strategies. Improved understanding of molecular abnormalities allows the development of personalized treatment approaches.

Gastric adenocarcinoma is a highly aggressive disease with poor overall survival. The aggressive nature of this disease is in part due to the high intra and inter tumoral heterogeneity and also due to the late diagnosis at presentation. Once progression occurs, treatment is more difficult due to the adaptation of tumors, which acquires resistance to commonly used chemotherapeutics. In this report, using publicly available data sets and pathway analysis, we highlight the vast heterogeneity of gastric cancer by investigating genes found to be significantly perturbed. We found several upregulated genes in the diffuse gastric cancer subtypes share similarity to gastric cancer as a whole which can be explained by the increase in this subtype of gastric cancer throughout the world. We report significant downregulation of genes that are underrepresented within the literature, such as ADH7, GCNT2, and LIF1, while other genes have not been explored within gastric cancer to the best of our knowledge such as METTL7A, MAL, CWD43, and SLC2A12. We identified gender to be another heterogeneous component of this disease and suggested targeted treatment strategies specific to this heterogeneity. In this study, we provide an in-depth exploration of the molecular landscape of gastric cancer in order to shed light onto novel areas of gastric cancer research and explore potential new therapeutic targets.

Pancreatic cancer (PC) is one of the most deadly cancers. The higher mortality is in part due to treatment resistance and early onset of metastasis. The existence of cancer-stem-like cells (CSLCs) has been widely accepted to be responsible for tumor aggressiveness in PC. Emerging evidence suggests that CSLCs have the capacity for increased cell growth, cell migration/invasion, metastasis, and treatment resistance, which leads to poor clinical outcome. However, the molecular role of CSLCs in tumor development and progression is poorly understood. Therefore, mechanistic understanding, and targeted killing of CSLCs may provide a newer therapeutic strategy for the treatment of PC. It has been well accepted that microRNAs (miRNAs) play critical roles during tumor development and progression through deregulation of multiple genes. Moreover, deregulated expression of miRNAs may also play a key role in the regulation of CSLC characteristics and functions. Here we show that isolated CD44(+)/CD133(+)/EpCAM(+) cells (triple-marker-positive cells) from human PC cell lines, MiaPaCa-2 and L3.6pl cells, display aggressive characteristics, such as increased cell growth, clonogenicity, cell migration, and self-renewal capacity, which is consistent with overexpression of CSLC signatures/markers. We also found deregulated expression of over 400 miRNAs, including let-7, miR-30, miR-125b, and miR-335, in CSLCs. As a proof-of-concept, knockdown of miR-125b resulted in the inhibition of tumor cell aggressiveness of CSLCs (triple-marker-positive cells), consistent with the downregulation of CD44, EpCAM, EZH2, and snail. These results clearly suggest the importance of miRNAs in the regulation of CSLC characteristics, and may serve as novel targets for therapy.

Background: Pancreatic ductal adenocarcinoma (PDAC) remains a deadly disease in urgent need of newer therapeutic modalities. Earlier we have shown that in PDAC, the over-expression of the nuclear exporter protein Exportin-1 (XPO1) leads to functional inactivation of tumor suppressor proteins (TSPs; FOXO3a, p27, Par-4 etc.) through mis-localization. We demonstrated that inhibition of XPO1 by CRISPR/Cas9 validated Selective Inhibitor of Nuclear Export (SINE) Selinexor and analogs restores the anti-tumor function of multiple TSPs leading to PDAC cell death and tumor inhibition in orthotopic models. Methods: Here we evaluate the synergy between SINE compounds and standard of care gemcitabine-nab-paclitaxel in PDAC models in vitro, in vivo and in a Phase Ib/2 trial (NCT02178436). Results: Selinexor and second generation SINE compound eltanexor synergized with gemcitabine (GEM) and nab-paclitaxel leading to suppression of PDAC growth, induction of apoptosis, and superior spheroid disintegration of PDAC derived cancer stem cells (CSCs). The observed synergy was due in part to enhanced nuclear localization of TSPs and suppression of both CSCs and epithelial-to-mesenchymal transition (EMT) markers. Label-Free quantitative (LFQ) proteome profiling with nuclear and cytoplasmic enrichment showed superior enhancement in nuclear protein fraction in combination treatment. The protein class with highest percent of nuclear retention were DNA binders. Selinexor and eltanexor as single agent (used at MTD) inhibited the growth of PDAC-CSC and two patient derived (Pdx) sub-cutaneous xenografts (p Conclusions: These results rationally fortify selinexor-gemcitabine-nab-paclitaxel as new and effective therapy for metastatic PDAC and strengthen our ongoing Phase II study. Citation Format: Asfar S. Azmi, Yosef Landesman, Michael Kauffman, Sharon Shacham, Gabriel Mpilla, Amro Aboukameel, Steve Kim, Mandana Kamgar, Anteneh Tesfaye, Ramzi M. Mohammad, Philip A. Philip. Evaluable antitumor activity in metastatic pancreatic adenocarcinoma with specific inhibitor of nuclear export based treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3476.

Background: Calcium Ca(2+) signals and the underlying Ca(2+) channels and transporters are known to influence development, growth, and metastasis of many cancers. Calcium release-activated calcium (CRAC) channel proteins, STIM and Orai, have been shown to play a role in cancer progression and metastasis. Here we investigate the impact of RP4010, a CRAC channel inhibitor, in GI [pancreatic ductal adenocarcinoma (PDAC), gastric cancer (GC) and pancreatic neuroendocrine tumors (PNETs)] cellular and patient derived tumor models. Methods: GI cancer cell lines [3 PDAC and one normal human pancreatic ductal adenocarcinoma (HPDE); 3 GC cells and 2 PNET cell lines] were exposed to RP4010 in the presence or absence of standard of care drugs such as gemcitabine, nab-paclitaxel, or everolimus. Cell growth inhibition was evaluated using MTT. Apoptosis was determined by Annexin V FITC and 7AAD assays. Alterations in markers associated with the CRAC channel pathway were evaluated using RT-PCR and Western Blotting. In vivo efficacy was evaluated in gastric cancer sub-cutaneous xenograft as well as a hyaluronan positive PDAC patient derived xenograft in the presence or absence of chemotherapeutic agents. Results: CRAC channel inhibition by RP4010 resulted in cancer cell selective growth inhibition (IC50s in the low micro M range). Growth inhibition was concurrent with apoptosis at similar doses. RP4010 synergized with gemcitabine and nab-paclitaxel in PDAC; nab-paclitaxel and docetaxel in GC (CI Conclusion: Our studies indicate that RP4010, a novel CRAC channel inhibitor could be a viable therapeutic option in GI cancers that need further clinical evaluation. A multi-center Phase I/IB dose-escalation trial evaluating the safety and efficacy of RP4010, a CRAC channel inhibitor in patients with relapsed or refractory Lymphomas is currently ongoing in USA (ClinicalTrials.gov Identifier: NCT03119467). Citation Format: Irfana Muqbil, Rachel Sexton, Gabriel Mpilla, Anteneh Tesfaye, Steve Kim, Philip A. Philip, Amro Aboukameel, Srikant Viswanadah, Kumar V. Penmesta, Ramzi M. Mohammad, Asfar S. Azmi. Efficacy of RP4010, a calcium release-activated calcium (CRAC) channel inhibitor, in preclinical models of gastrointestinal cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3069.

// Jiankun Gao 1,2 , Asfar S. Azmi 3 , Amro Aboukameel 2 , Michael Kauffman 4 , Sharon Shacham 4 , Abdul-Badi Abou-Samra 5 , and Ramzi M. Mohammad 2,5 1 Sichuan College of Traditional Chinese Medicine, Mianyang, Sichuan, People’s Republic of China 2 Department of Oncology, Karmanos Cancer Institute, Detroit, Michigan, USA 3 Department of Pathology, School of Medicine, Wayne State University, Detroit, Michigan, USA 4 Karyopharm Therapeutics, Natick MA, USA 5 Hamad Medical Corporation, Doha, Qatar Correspondence: Ramzi M. Mohammad, email: // Keywords :Specific Inhibitors of Nuclear Export; Xpo1, Exportin 1, CRM1 inhibitor; Notch1; Fbw7; Apoptosis; Pancreatic Cancer Received : January 8, 2014 Accepted :March 19, 2014 Published : March 21, 2014 Abstract Chromosome maintenance region 1 (CRM1) also called Exportin 1 (Xpo1), a protein found elevated in pancreatic ductal adenocarcinoma (PDAC), blocks tumor suppressor protein (TSP) function through constant nuclear export. Earlier we had shown that targeting CRM1 by our newly developed specific inhibitors of nuclear export (SINE) leads to inhibition of pancreatic cancer cell proliferation and tumor growth arrest. In this paper we define the mechanism of SINE action. Our lead SINE KPT-185 inhibits PDAC cell growth, cell migration, tumor invasion and induces apoptosis and G2-M cell cycle arrest in low nano molar range (IC 50s ~150 nM). Mechanistically we demonstrate that the activity of KPT-185 is associated with nuclear retention of Fbw7; which degrades nuclear Notch-1 leading to decreased tumor promoting markers such as C-Myc, Cyclin-D1, Hes1 and VEGF. The orally bioavailable SINE (KPT-251) showed potent anti-tumor activity in a Colo-357 PDAC xenografts model; residual tumor analysis showed activation of Fbw7 concomitant with attenuation of Notch1 and its downstream genes. These results suggest that the antitumor activity of KPT-185 is in part due to nuclear retention of Fbw7 and consequent Notch1 degradation. The new CRM1 inhibitors, therefore, hold strong potential and warrant further clinical investigations for PDAC.

Trafficking of biological material across membranes is an evolutionary conserved mechanism and is part of any normal cell homeostasis. Such transport is composed of active, passive, export through microparticles, and vesicular transport (exosomes) that collectively maintain proper compartmentalization of important micro- and macromolecules. In pathological states, such as cancer, aberrant activity of the export machinery results in expulsion of a number of key proteins and microRNAs resulting in their misexpression. Exosome-mediated expulsion of intracellular drugs could be another barrier in the proper action of most of the commonly used therapeutics, targeted agents, and their intracellular metabolites. Over the last decade, a number of studies have revealed that exosomes cross-talk and/or influence major tumor-related pathways, such as hypoxia-driven epithelial-to-mesenchymal transition, cancer stemness, angiogenesis, and metastasis involving many cell types within the tumor microenvironment. Emerging evidence suggests that exosome-secreted proteins can also propel fibroblast growth, resulting in desmoplastic reaction, a major barrier in effective cancer drug delivery. This comprehensive review highlights the advancements in the understanding of the biology of exosomes secretions and the consequence on cancer drug resistance. We propose that the successful combination of cancer treatments to tackle exosome-mediated drug resistance requires an interdisciplinary understanding of these cellular exclusion mechanisms, and how secreted biomolecules are involved in cellular cross-talk within the tumor microenvironment.

// Changwen Ning 1 , Min Liang 1 , Shuang Liu 1 , Guan Wang 1 , Holly Edwards 2, 3 , Yang Xia 4 , Lisa Polin 2, 3 , Gregory Dyson 2 , Jeffrey W. Taub 3, 5, 6 , Ramzi M. Mohammad 2, 3 , Asfar S. Azmi 2, 3 , Lijing Zhao 7 and Yubin Ge 2, 3, 5 1 National Engineering Laboratory for AIDS Vaccine, Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, School of Life Sciences, Jilin University, Changchun, P.R. China 2 Department of Oncology, Wayne State University School of Medicine, Detroit, MI, USA 3 Molecular Therapeutics Program, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI, USA 4 Department of Pathology, The Second Hospital of Jilin University, Changchun, P.R. China 5 Department of Pediatrics, Wayne State University School of Medicine, Detroit, MI, USA 6 Division of Pediatric Hematology/Oncology, Children’s Hospital of Michigan, Detroit, MI, USA 7 Department of Rehabilitation, School of Nursing, Jilin University, Changchun, P.R. China Correspondence to: Yubin Ge, email: gey@karmanos.org Lijing Zhao, email: zhao_lj@jlu.edu.cn Keywords: pancreatic cancer, PI3K/mTOR, ERK, VS-5584, SCH772984 Received: March 29, 2017 Accepted: May 01, 2017 Published: May 15, 2017 ABSTRACT Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease in urgent need of newer therapeutic modalities. Majority of patients with PDAC have mutations in KRAS, which unfortunately remains an ineffectual target. Our strategy here is to target KRAS downstream effectors PI3K and mTOR. In this study, we investigated the antitumor efficacy of the novel PI3K and mTOR dual inhibitor VS-5584 in PDAC. Our data shows that PI3K/mTOR dual inhibition causes ERK activation in all tested PDAC cell lines. Although the MEK inhibitor GSK1120212 could abrogate VS-5584-induced ERK activation, it did not substantially enhance cell death in all the cell lines tested. However, combination with ERK inhibitor SCH772984 not only mitigated VS-5584-induced ERK activation but also enhanced VS-5584-induced cell death. In a xenograft model of PDAC, we observed 28% and 44% tumor inhibition for individual treatment with VS-5584 and SCH772984, respectively, while the combined treatment showed superior tumor inhibition (80%) compared to vehicle control treatment. Our findings support the clinical development of VS-5584 and ERK inhibitor combination for PDAC treatment.

The theory of cancer stem cells (CSCs) has provided evidence on fundamental clinical implications because of the involvement of CSCs in cell migration, invasion, metastasis, and treatment resistance, which leads to the poor clinical outcome of cancer patients. Therefore, targeting CSCs will provide a novel therapeutic strategy for the treatment and/or prevention of tumors. However, the regulation of CSCs and its signaling pathways during tumorigenesis are not well understood. MicroRNAs (miRNAs) have been proved to act as key regulators of the post-transcriptional regulation of genes, which involve in a wide array of biological processes including tumorigenesis. The altered expressions of miRNAs are associated with poor clinical outcome of patients diagnosed with a variety of tumors. Therefore, emerging evidence strongly suggest that miRMAs play critical roles in tumor development and progression. Emerging evidence also suggest that miRNAs participate in the regulation of tumor cell growth, migration, invasion, angiogenesis, drug resistance, and metastasis. Moreover, miRNAs such as let-7, miR-21, miR-22, miR-34, miR-101, miR-146a, and miR-200 have been found to be associated with CSC phenotype and function mediated through targeting oncogenic signaling pathways. In this article, we will discuss the role of miRNAs in the regulation of CSC phenotype and function during tumor development and progression. We will also discuss the potential role of naturally occurring agents (nutraceuticals) as potent anti-tumor agents that are believed to function by targeting CSC-related miRNAs.

Challenges in targeting the KRAS pathway Oncogenic Ras (KRAS) is one of the most prevalent somatic aberrations in cancer [1]. KRAS acts as a molecular switch that recruits and activates a repertoire of proteins necessary for cell proliferation, desmoplasia, maintenance of tumor heterogeneity (cancer stem-like cells), tumor aggressiveness and metastases [2]. Even though there is a consensus regarding the importance of KRAS in cancer, the absence of a typical drug binding pocket in its structure has kept KRAS as an elusive target for more than three decades [3]. While targeted agents against important members downstream of KRAS such as PI3K, AKT, MEK and EGFR do show initial response, resistance develops in almost all instances, thereby making these targets ineffectual [4]. Therefore, in order to overcome this challenge, newer druggable avenues either through the Ras structure itself or through critical direct interacting partners or downstream effectors of this master oncogenic regulator are urgently needed [5]. This article builds the case for the p21-activated kinases (PAKs) in general and PAK4 in particular as unique druggable avenues that are downstream of KRAS signaling.

Asfar S. Azmi 1 , Sanjeev Banerjee 1 , Shadan Ali 1 , Zhiwei Wang 1 , Bin Bao 1 , Frances W.J. Beck 2 , Main Maitah 2 , Minsig Choi 2 , Tony F. Shields 2 , Philip A. Philip 2 , Fazlul H. Sarkar 1 , Ramzi M. Mohammad 2 1 Department of Pathology, Wayne State University School of Medicine 2 Departments of Oncology, Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan Keywords: MDM2 and p53, MI-219, oxaliplatin Network Modeling Received: April 28, 2011; Accepted: May 11, 2011; Published: May 16, 2011; Correspondence: Fazlul H Sarkar, e-mail: // Ramzi M. Mohammad, e-mail: // // Abstract Earlier we had shown that the MDM2 inhibitor (MI-219) belonging to the spiro-oxindole family can synergistically enhance the efficacy of platinum chemotherapeutics leading to 50% tumor free survival in a genetically complex pancreatic ductal adenocarcinoma (PDAC) xenograft model. In this report, we have taken a systems and network modeling approach in order to understand central mechanisms behind MI219-oxaliplatin synergy with validation in PDAC, colon and breast cancer cell lines. Microarray profiling of drug treatments (MI-219, oxaliplatin or their combination) in capan-2 cells reveal a similar unique set of gene alterations that is duplicated in other solid tumor cells. As single agent, MI-219 or oxaliplatin induced alterations in 48 and 761 genes respectively. The combination treatment resulted in 767 gene alterations with emergence of 286 synergy unique genes. Ingenuity network modeling of combination and synergy unique genes showed the crucial role of five key local networks CREB, CARF, EGR1, NF-kB and E Cadherin. The network signatures were validated at the protein level in all three cell lines. Individually silencing central nodes in these five hubs resulted in abrogation of MI-219-oxaliplatin activity confirming their critical role in aiding p53 mediated apoptotic response. We anticipate that our MI219-oxaliplatin network blueprints can be clinically translated in the rationale design and application of this unique therapeutic combination in a genetically pre-defined subset of patients.

The discovery of small molecule inhibitors of HDM2-p53 interaction is considered one of the most significant therapeutic developments in the area p53 research. Intensive work on different classes of HDM2 inhibitors has proven their therapeutic utility as activators of p53 in multiple tumor models. Many laboratories have shown that HDM2 inhibitors can synergize with chemotherapeutic agents resulting in enhanced efficacy through both p53-dependent and independent mechanisms. In our hands HDM2 inhibitor and platinum drug combination showed remarkable antitumor activity that led tumor free survival in one of the most resistant and complex pancreatic xenograft models. Although antitumor efficacy of such combinations has been studied in detail, not much is known on the molecular mechanisms governing this synergy. This is partly due to complexity of multiple pathways modulated by p53 and HDM2. We are of the view that in order to decode this complexity, an integrated approach is needed that considers both HDM2 and p53 as components of a network and not in isolation. This review highlights recent advancements in our understanding of HDM2 inhibitor combination therapy based on network modeling and systems biology driven science. Our recent findings support such a network view as integrated gene expression profiling and pathway network modeling on MI-219-oxaliplatin treated cells revealed activation of multiple and closely knit biological networks. We anticipate that in the near future such network-centric approaches will benefit clinical development of HDM2 inhibitors for genetically predefined subsets of cancer patients and this will be a step towards personalized medicine.

Thymoquinone (TQ) is the predominant bioactive constituent present in black seed oil (Nigella sativa) and has been tested for its efficacy against cancer. Here, we summarize the literature about TQ's molecular mechanism of action and its ability to induce apoptosis and inhibit tumor growth in preclinical models. TQ has anti-inflammatory effects, and it inhibits tumor cell proliferation through modulation of apoptosis signaling, inhibition of angiogenesis, and cell cycle arrest. Chemosensitization by TQ is mostly limited to in vitro studies, and it has potential in therapeutic strategy for cancer. The results favor efficacy and enhancement of therapeutic benefit against tumor cells resistant to therapy based on cellular targets that are molecular determinants for cancer cell survival and progression. There have been attempts to synthesize novel analogs of TQ directed toward superior effects in killing tumor cells with more enhanced chemosensitizing potential than parent TQ compound. Based on published reports, we believe that further in-depth studies are warranted including investigation of its bioavailability and Phase I toxicity profiling in human subjects. The results from such studies will be instrumental in advancing this field in support of initiating clinical trials for testing the effects of this ancient agent in cancer therapy.

The high mortality rate associated with Gastric Cancer (GC) indicates the urgent need for actionable therapeutic targets. The nuclear exporter protein exportin 1 (XPO1/CRM1) is the exclusive exporter of many tumor suppressor proteins (TPSs) and growth regulators. XPO1 is often over-expressed in different malignancies leading to aberrant cytoplasmic localization of TSPs and subsequent inactivation. A detailed analysis on the correlation of XPO1 with inflammation-metaplasia-dysplasia-carcinoma sequence progression was performed using immunohistochemistry in 70 GC cases: (a) 10 cases from normal gastric mucosa, (b) 10 cases of stomach with intestinal metaplasia with and without inflammation, (c) 10 cases of mucosa with low-grade dysplasia (d) 10 cases of mucosa with high-grade dysplasia, (e) 10 cases of gastric adenocarcinoma and (f) 20 cases of metastatic gastric carcinoma. A correlation between XPO1 expression, the pathological and clinical features of the disease as well as survival were analyzed. Gastric cancer cell lines were exposed to the Selective Inhibitors of Nuclear Export (SINE) compounds (selinexor, KPT-8602, KPT-185, or the natural agent, leptomycin B (LMB), then analyzed using cytotoxicity and molecular assays. In addition, the activity of selinexor was evaluated in a sub-cutaneous xenograft of gastric cancer cell line NCI-N87. XPO1 served as a prognostic marker for poor outcome as positive staining of XPO1 in GC correlated with aggressive behavior of the disease. Targeting XPO1 using SINE compounds or LMB resulted in inhibition of GC cellular growth (IC50 Citation Format: Irfana Muqbil, Zaid Mahdi, Rahman Choudhary, Erkan Baloglu, William Senapedis, Yosef Landesman, Sharon Shacham, Michael Kauffman, Steve Kim, Rafic Beydoun, Richard N. Berri, Anthony Shields, Ramzi M. Mohammad, Asfar S. Azmi. Nuclear exporter protein XPO1 a novel prognostic and therapeutic target in gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2491.

Cancer chemoprevention is defined as the use of natural, synthetic, or biological agents to suppress, reverse or prevent the carcinogenic process from turning into aggressive cancer. Prostate apoptosis response-4 (Par-4) is a unique pro-apoptotic protein that selectively induces apoptosis in prostate cancer cells. However, its role in other malignancies has not been fully explored. This study tries to identify the functional significance of Par-4 in pancreatic cancer.Multiple molecular techniques such as Western blot analysis, trypan blue assay for cell viability, MTT assay for cell growth inhibition and Histone/DNA ELISA for apoptosis were used.Western blot analysis revealed that 3,3'-diindolylmethane (DIM) a chemopreventive agent, specifically its more bioavailable formulation, B-DIM, at low doses (20 micromol/L) induces Par-4, in L3.6pl and Colo-357 pancreatic cancer cells. At similar doses, DIM reduced cell viability and caused cell growth inhibition and apoptosis. Moreover, DIM pre-treatment sensitized the cells to cytotoxic action of chemotherapeutic drug gemcitabine through up-regulation of Par-4.The induction of Par-4 is indirectly related to increased sensitivity and cell death through apoptosis. To our knowledge the results reported here showed, for the first time, the induction of Par-4 by chemopreventive agents, in general, and DIM, in particular, in pancreatic cancer cells in vitro.

Recent advancements in cancer research have led to some major breakthroughs; however, the impact on overall cancer-related death rate remains unacceptable, suggesting that further insight into tumor markers and development of targeted therapies is urgently needed. The urokinase plasminogen activator (uPA) system represents a family of serine proteases that are involved in the degradation of basement membrane and the extracellular matrix, leading to tumor cell invasion and metastasis. In this review, we have provided an overview of emerging data, from basic research as well as clinical studies, highlighting the evolving role of uPA/uPAR system in tumor progression. It is currently believed that the expression and activation of uPA plays an important role in tumorigenicity, and high endogenous levels of uPA and uPAR are associated with advanced metastatic cancers. The endogenous inhibitors of this system, PAI-1 and PAI-2, regulate uPA-uPAR activity by either direct inhibition or affecting cell surface expression and internalization. PAI-1's role in cancers is rather unusual; on one hand, it inhibits uPA-uPAR leading to inhibition of invasion and metastasis and on the other it has been reported to facilitate tumor growth and angiogenesis. Individual components of uPA/uPAR system are reported to be differentially expressed in cancer tissues compared to normal tissues and, thus, have the potential to be developed as prognostic and/or therapeutic targets. Therefore, this system represents a highly attractive target that warrants further in-depth studies. Such studies are likely to contribute towards the development of molecularly-driven targeted therapies in the near future.

Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-κB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes.

Under a Creative Commons license.-- Review.-- et al., Targeted therapies and the consequent adoption of >personalized> oncology have achieved notablesuccesses in some cancers; however, significant problems remain with this approach. Many targetedtherapies are highly toxic, costs are extremely high, and most patients experience relapse after a fewdisease-free months. Relapses arise from genetic heterogeneity in tumors, which harbor therapy-resistantimmortalized cells that have adopted alternate and compensatory pathways (i.e., pathways that are notreliant upon the same mechanisms as those which have been targeted). To address these limitations, aninternational task force of 180 scientists was assembled to explore the concept of a low-toxicity >broad-spectrum> therapeutic approach that could simultaneously target many key pathways and mechanisms. Using cancer hallmark phenotypes and the tumor microenvironment to account for the various aspectsof relevant cancer biology, interdisciplinary teams reviewed each hallmark area and nominated a widerange of high-priority targets (74 in total) that could be modified to improve patient outcomes. For thesetargets, corresponding low-toxicity therapeutic approaches were then suggested, many of which werephytochemicals. Proposed actions on each target and all of the approaches were further reviewed forknown effects on other hallmark areas and the tumor microenvironment. Potential contrary or procar-cinogenic effects were found for 3.9% of the relationships between targets and hallmarks, and mixedevidence of complementary and contrary relationships was found for 7.1%. Approximately 67% of therelationships revealed potentially complementary effects, and the remainder had no known relationship. Among the approaches, 1.1% had contrary, 2.8% had mixed and 62.1% had complementary relationships. These results suggest that a broad-spectrum approach should be feasible from a safety standpoint. Thisnovel approach has potential to be relatively inexpensive, it should help us address stages and types ofcancer that lack conventional treatment, and it may reduce relapse risks. A proposed agenda for futureresearch is offered., Amr Amin was funded by Terry Fox Foundation Grant # TF-13-20 and UAEU Program for Advanced Research (UPAR) #31S118; Jack Arbiser was funded by NIHAR47901; Alexandra Arreola was funded by NIH NRSA Grant F31CA154080; Alla Arzumanyan was funded by NIH (NIAID) R01: Combination therapies for chronic HBV, liver disease, and cancer (AI076535); Work in the lab of Asfar S. Azmi is supported by NIH R21CA188818 as well as from Sky Foundation Inc. Michigan; Fabian Benencia was supported by NIH Grant R15 CA137499-01; Alan Bilsland was supported by the University of Glasgow, Beatson Oncology Centre Fund, CRUK (www.cancerresearchuk.org) Grant C301/A14762; Amancio Carnero was supported by grants from the Spanish Ministry of Economy and Competitivity, ISCIII (Fis: PI12/00137, RTICC: RD12/0036/0028) co-funded by FEDER from Regional Development European Funds (European Union), Consejeria de Ciencia e Innovacion (CTS-6844 and CTS-1848) and Consejeria de Salud of the Junta de Andalucia (PI-0135-2010 and PI-0306-2012). His work on this project has also been made possible thanks to the Grant PIE13/0004 co-funded by the ISCIII and FEDER funds; Stephanie C. Casey was supported by NIH Grant F32CA177139; Mrinmay Chakrabarti was supported by the United Soybean Board; Rupesh Chaturvedi was supported by an NIH NCCAM Grant (K01AT007324); Georgia Zhuo Chen was supported by an NIH NCI Grant (R33 CA161873-02); Helen Chen acknowledges financial support from the Michael Cuccione Childhood Cancer Foundation Graduate Studentship; Sophie Chen acknowledges financial support from the Ovarian and Prostate Cancer Research Trust, UK; Yi Charlie Chen acknowledges financial support from the West Virginia Higher Education Policy Commission/Division of Science Research, his research was also supported by NIH grants (P20RR016477 and P20GM103434) from the National Institutes of Health awarded to the West Virginia IDeA Network of Biomedical Research Excellence; Maria Rosa Ciriolo was partially supported by the Italian Association for Cancer Research (AIRC) Grants #IG10636 and #15403; Helen M. Coley acknowledges financial support from the GRACE Charity, UK and the Breast Cancer Campaign, UK; Marisa Connell was supported by a Michael Cuccione Childhood Cancer Foundation Postdoctoral Fellowship; Sarah Crawford was supported by a research grant from Connecticut State University; Charlotta Dabrosin acknowledges financial support from the Swedish Research Council and the Swedish Research Society; Giovanna Damia gratefully acknowledges the generous contributions of The Italian Association for Cancer Research (IG14536 to G.D.), Santanu Dasgupta gratefully acknowledges the support of the University of Texas Health Science Centre at Tyler, Elsa U. Pardee Foundation; William K. Decker was supported in part by CPRIT, the Cancer Prevention and Research Institute of Texas; Anna Mae E. Diehl was supported by NIH National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), the NIH National Institute on Alcohol Abuse and Alcoholism (NIAAA), Gilead and Shire Pharmaceuticals; Q. Ping Dou was partially supported by NIH/NCI (1R01CA20009, 5R01CA127258-05 and R21CA184788), and NIH P30 CA22453 (to Karmanos Cancer Institute); Janice E. Drew was supported by the Scottish Government's Rural and Environment Science and Analytical Services Division; Eyad Elkord thanks the National Research Foundation, United Arab Emirates University and the Terry Fox Foundation for supporting research projects in his lab; Bassel El-Rayes was supported by Novartis Pharmaceutical, Aveo Pharmaceutical, Roche, Bristol Myers Squibb, Bayer Pharmaceutical, Pfizer, and Kyowa Kirin; Mark A. Feitelson was supported by NIH/NIAID Grant AI076535, Dean W. Felsher was supported by NIH grants (R01CA170378, U54CA149145, and U54CA143907); Lynnette R Ferguson was financially supported by the Auckland Cancer Society and the Cancer Society of New Zealand; Gary L. Firestone was supported by NIH Public Service Grant CA164095 awarded from the National Cancer Institute; Christian Frezza “would like to acknowledge funding from a Medical Research Council CCU-Program Grant on cancer metabolism, and a unique applicant AICR project grant”; Mark M. Fuster was supported by NIH Grant R01-HL107652; Alexandros G. Georgakilas was supported by an EU Marie Curie Reintegration Grant MC-CIG-303514, Greek National funds through the Operational Program ‘Educational and Lifelong Learning of the National Strategic Reference Framework (NSRF)-Research Funding Program THALES (Grant number MIS 379346) and COST Action CM1201 ‘Biomimetic Radical Chemistry’; Michelle F. Green was supported by a Duke University Molecular Cancer Biology T32 Training Grant; Brendan Grue was supported by a National Sciences Engineering and Research Council Undergraduate Student Research Award in Canada; Dorota Halicka was supported by by NIH NCI grant NCI RO1 28704; Petr Heneberg was supported by the Charles University in Prague projects UNCE 204015 and PRVOUK P31/2012, by the Czech Science Foundation projects 15-03834Y and P301/12/1686, by the Czech Health Research Council AZV project 15-32432A, and by the Internal Grant Agency of the Ministry of Health of the Czech Republic project NT13663-3/2012; Matthew D. Hirschey wishes to acknowledge Duke University Institutional Support, the Duke Pepper Older Americans Independence Center (OAIC) Program in Aging Research supported by the National Institute of Aging (P30AG028716-01) and NIH/NCI training grants to Duke University (T32-CA059365-19 and 5T32-CA059365), Lorne J. Hofseth was supported by NIH grants (1R01CA151304, 1R03CA1711326, and 1P01AT003961); Kanya Honoki was supported in part by the grant from the Ministry of Education, Culture, Sports, Science and Technology, Japan (No. 24590493); Hsue-Yin Hsu was supported in part by grants from the Ministry of Health and Welfare (CCMP101-RD-031 and CCMP102-RD-112) and Tzu-Chi University (61040055-10) of Taiwan; Lasse D. Jensen was supported by Svenska Sallskapet for Medicinsk Forskning, Gosta Fraenkels Stiftelse, Ak.e Wibergs Stiftelse, Ollie och Elof Ericssons Stiftelse, Linkopings Universitet and the Karolinska Institute, Sweden; Wen G. Jiang wishes to acknowledge the support by Cancer Research Wales, the Albert Hung Foundation, the Fong Family Foundation, and Welsh Government A4B scheme; Lee W. Jones was supported in part by grants from the NIH NCI; W Nicol Keith was supported by the University of Glasgow, Beatson Oncology Centre Fund, CRUK (www.cancerresearchuk.org) Grant C301/A14762; Sid P. Kerkar was supported by the NIH Intramural Research Program; Rob J. Kulathinal was supported by the National Science Foundation, and the American Cancer Society; Byoung S. Kwon was supported in part by National Cancer Center (NCC-1310430-2) and National Research Foundation (NRF-2005-0093837); Anne Le was supported by Sol Goldman Pancreatic Cancer Research Fund Grant 80028595, a Lustgarten Fund Grant 90049125 and Grant NIHR21CA169757 (to Anne Le); Michael A. Lea was funded by the The Alma Toorock Memorial for Cancer Research; Ho-Young Lee., This work was supported by grants from the National Research Foundation of Korea (NRF), the Ministry of Science, ICT & Future Planning (MSIP), Republic of Korea (Nos. 2011-0017639 and 2011-0030001) and by a NIH Grant R01 CA100816; Liang-Tzung Lin was supported in part by a grant from the Ministry of Education of Taiwan (TMUTOP103005-4); Jason W. Locasale acknowledges support from NIH awards (CA168997 and AI110613) and the International Life Sciences Institute; Bal L. Lokeshwar was supported in part by United States’ Public Health Services Grants: NIH R01CA156776 and VA-BLR&D Merit Review Grant No. 5I01-BX001517-02; Valter D. Longo acknowledges support from NIH awards (P01AG034906 and R01AG020642) and from the V Foundation; Costas A. Lyssiotis was funded in part by the Pancreatic Cancer Action Network as a Pathway to Leadership Fellow and through a Dale F. Frey Breakthrough award from the Damon Runyon Cancer Research Foundation; Karen L. MacKenzie wishes to acknowledge the support from the Children's Cancer Institute Australia (affiliated with the University of New South Wales, Australia and the Sydney Children's Hospital Network); Maria Marino was supported by grant from University Roma Tre to M.M. (CLA 2013) and by the Italian Association for Cancer Research (AIRC-Grant #IG15221), Ander Matheu is funded by Carlos III Health Institute (AM: CP10/00539), Basque Foundation for Science (IKERBASQUE) and Marie Curie CIG Grant (AM: 2012/712404); Christopher Maxwell was supported by funding from the Canadian Institutes of Health Research, in partnership with the Avon Foundation for Women (OBC-134038) and the Canadian Institutes of Health Research New Investigator Salary Award (MSH-136647); Eoin McDonnell received Duke University Institutional Support; Kapil Mehta was supported by Bayer Healthcare System G4T (Grants4Targets); Gregory A. Michelotti received support from NIH NIDDK, NIH NIAAA, and Shire Pharmaceuticals; Vinayak Muralidhar was supported by the Harvard-MIT Health Sciences and Technology Research Assistantship Award; Elena Niccolai was supported by the Italian Ministry of University and the University of Italy; Virginia R. Parslow gratefully acknowledges the financial support of the Auckland Cancer Society Research Centre (ACSRC); Graham Pawelec was supported by the German Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung, BMBF) Grant number 16SV5536K, and by the European Commission (FP7 259679 “IDEAL”); Peter L. Pedersen was supported by NIH Grant CA-10951; Brad Poore was supported by Sol Goldman Pancreatic Cancer Research Fund Grant 80028595, the Lustgarten Fund Grant 90049125, and Grant NIHR21CA169757 (to Anne Le); Satya Prakash was supported by a Canadian Institutes of Health Research Grant (MOP 64308); Lizzia Raffaghello was supported by an NIH Grant (P01AG034906-01A1) and Cinque per Mille dell’IRPEF–Finanziamento della Ricerca Sanitaria; Jeffrey C. Rathmell was supported by an NIH Grant (R01HL108006); Swapan K. Ray was supported by the United Soybean Board; Domenico Ribatti received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under Grant agreement n°278570; Luigi Ricciardiello was supported by the AIRC Investigator Grants 10216 and 13837, and the European Community's Seventh Framework Program FP7/2007–2013 under Grant agreement 311876; Francis Rodier acknowledges the support of the Canadian Institute for Health Research (FR: MOP114962, MOP125857), Fonds de Recherche Québec Santé (FR: 22624), and the Terry Fox Research Institute (FR: 1030), Gian Luigi Russo contributed to this effort while participating in the Fulbright Research Scholar Program 2013–14; Isidro Sanchez-Garcia is partially supported by FEDER and by MICINN (SAF2012-32810), by NIH Grant (R01 CA109335-04A1), by Junta de Castilla y León (BIO/SA06/13) and by the ARIMMORA project (FP7-ENV-2011, European Union Seventh Framework Program). Isidro Sanchez-Garcia's lab is also a member of the EuroSyStem and the DECIDE Network funded by the European Union under the FP7 program; Andrew J. Sanders wishes to acknowledge the support by Cancer Research Wales, the Albert Hung Foundation, the Fong Family Foundation, and Welsh Government A4B scheme; Neeraj K. Saxena was supported by grant funding from NIH NIDDK (K01DK077137, R03DK089130); Dipali Sharma was partially funded by NIH NCI grants (R01CA131294, R21 CA155686), the Avon Foundation and a Breast Cancer Research Foundation Grant (90047965); Markus David Siegelin received funding from National Institute of Health, NINDS Grant K08NS083732, and the 2013 AACR-National Brain Tumor Society Career Development Award for Translational Brain Tumor Research, Grant Number 13-20-23-SIEG; Neetu Singh was supported by funds from the Department of Science and Technology (SR/FT/LS-063/2008), New Delhi, India; Carl Smythe was supported by Yorkshire Cancer Research and The Wellcome Trust, UK; Carmela Spagnuolo was supported by funding from Project C.I.S.I.A., act n. 191/2009 from the Italian Ministry of Economy and Finance Project CAMPUS-QUARC, within program FESR Campania Region 2007/2013, objectives 2.1, 2.2; Diana M. Stafforini was supported by grants from the National Cancer Institute (5P01CA073992), IDEA Award W81XWH-12-1-0515 from the Department of Defense, and by the Huntsman Cancer Foundation; John Stagg was supported by the Canadian Institutes of Health Research; Pochi R. Subbarayan was supported by the University of Miami Clinical and Translational Science Institute (CTSI) Pilot Research Grant (CTSI-2013-P03) and SEEDS You Choose Awards; Phuoc T. Tran was funded by the DoD (W81XWH-11-1-0272 and W81XWH-13-1-0182), a Kimmel Translational Science Award (SKF-13-021), an ACS Scholar award (122688-RSG-12-196-01-TBG) and the NIH (R01CA166348); Kathryn E. Wellen receives funding from the National Cancer Institute, Pancreatic Cancer Action Network, Pew Charitable Trusts, American Diabetes Association, and Elsa U. Pardee Foundation; Huanjie Yang was partially supported by the Scientific Research Foundation for the Returned Oversea Scholars, State Education Ministry and Scientific and Technological Innovation Project, Harbin (2012RFLXS011), Paul Yaswen was supported by funding from the United States National Institutes of Health (ES019458) and the California Breast Cancer Research Program (17UB-8708); Clement Yedjou was supported by a grant from the National Institutes of Health (Grant # G1200MD007581), through the RCMI-Center for Environmental Health; Xin Yin was supported by NIH/National Heart, Lung, and Blood Institute Training Grant T32HL098062.; Jiyue Zhu was supported by NIH Grant R01GM071725; Massimo Zollo was supported by the European FP7-TuMIC HEALTH-F2-2008-201662, the Italian Association for Cancer research (AIRC) Grant IG # 11963 and the Regione Campania L.R:N.5, the European National Funds PON01-02388/1 2007-2013.

Apoptosis or programmed cell death is natural way of removing aged cells from the body. Most of the anti-cancer therapies trigger apoptosis induction and related cell death networks to eliminate malignant cells. However, in cancer, de-regulated apoptotic signaling, particularly the activation of an anti-apoptotic systems, allows cancer cells to escape this program leading to uncontrolled proliferation resulting in tumor survival, therapeutic resistance and recurrence of cancer. This resistance is a complicated phenomenon that emanates from the interactions of various molecules and signaling pathways. In this comprehensive review we discuss the various factors contributing to apoptosis resistance in cancers. The key resistance targets that are discussed include (1) Bcl-2 and Mcl-1 proteins; (2) autophagy processes; (3) necrosis and necroptosis; (4) heat shock protein signaling; (5) the proteasome pathway; (6) epigenetic mechanisms; and (7) aberrant nuclear export signaling. The shortcomings of current therapeutic modalities are highlighted and a broad spectrum strategy using approaches including (a) gossypol; (b) epigallocatechin-3-gallate; (c) UMI-77 (d) triptolide and (e) selinexor that can be used to overcome cell death resistance is presented. This review provides a roadmap for the design of successful anti-cancer strategies that overcome resistance to apoptosis for better therapeutic outcome in patients with cancer.

Cancer immune evasion is a major stumbling block in designing effective anticancer therapeutic strategies. Although considerable progress has been made in understanding how cancers evade destructive immunity, measures to counteract tumor escape have not kept pace. There are a number of factors that contribute to tumor persistence despite having a normal host immune system. Immune editing is one of the key aspects why tumors evade surveillance causing the tumors to lie dormant in patients for years through “equilibrium” and “senescence” before re-emerging. In addition, tumors exploit several immunological processes such as targeting the regulatory T cell function or their secretions, antigen presentation, modifying the production of immune suppressive mediators, tolerance and immune deviation. Besides these, tumor heterogeneity and metastasis also play a critical role in tumor growth. A number of potential targets like promoting Th1, NK cell, γδ T cell responses, inhibiting Treg functionality, induction of IL-12, use of drugs including phytochemicals have been designed to counter tumor progression with much success. Some natural agents and phytochemicals merit further study. For example, use of certain key polysaccharide components from mushrooms and plants have shown to possess therapeutic impact on tumor-imposed genetic instability, anti-growth signaling, replicative immortality, dysregulated metabolism etc. In this review, we will discuss the advances made toward understanding the basis of cancer immune evasion and summarize the efficacy of various therapeutic measures and targets that have been developed or are being investigated to enhance tumor rejection.

Cancer is a key health issue across the world, causing substantial patient morbidity and mortality. Patient prognosis is tightly linked with metastatic dissemination of the disease to distant sites, with metastatic diseases accounting for a vast percentage of cancer patient mortality. While advances in this area have been made, the process of cancer metastasis and the factors governing cancer spread and establishment at secondary locations is still poorly understood. The current article summarizes recent progress in this area of research, both in the understanding of the underlying biological processes and in the therapeutic strategies for the management of metastasis. This review lists the disruption of E-cadherin and tight junctions, key signaling pathways, including urokinase type plasminogen activator (uPA), phosphatidylinositol 3-kinase/v-akt murine thymoma viral oncogene (PI3K/AKT), focal adhesion kinase (FAK), β-catenin/zinc finger E-box binding homeobox 1 (ZEB-1) and transforming growth factor beta (TGF-β), together with inactivation of activator protein-1 (AP-1) and suppression of matrix metalloproteinase-9 (MMP-9) activity as key targets and the use of phytochemicals, or natural products, such as those from Agaricus blazei, Albatrellus confluens, Cordyceps militaris, Ganoderma lucidum, Poria cocos and Silybum marianum, together with diet derived fatty acids gamma linolenic acid (GLA) and eicosapentanoic acid (EPA) and inhibitory compounds as useful approaches to target tissue invasion and metastasis as well as other hallmark areas of cancer. Together, these strategies could represent new, inexpensive, low toxicity strategies to aid in the management of cancer metastasis as well as having holistic effects against other cancer hallmarks.

Inflammation is a complex and critical immunological process resulting from host defense mechanisms against trauma, microorganism infection, or other adverse environmental stress or complex combinations of many biological insults sustained by humans. Such inflammatory processes, especially the sustained chronic condition of inflammation, along with inflammation-induced oxidative stress, can lead to irreversible cellular or tissue damage over time, which further contributes to the development of chronic degenerative diseases including cancers. The aging process is another complicated, multifactorial, and inherent biological process that progressively accumulates deleterious damage at the molecular, cellular, tissue, and even organ levels in the body during its maturation following birth, giving rise to alterations in physiological and biochemical functions, and eventually leading to increased vulnerability to diseases including cancers. In this chapter, we will discuss the role of chronic inflammation, oxidative stress, and DNA damage in the aging process, especially in age-related degenerative diseases including cancer. We will also discuss the role of zinc as an anti-inflammatory and antioxidant agent in human health and disease, and its potential role as an anti-aging agent. Finally, we will discuss the detailed mechanisms of the protective action of zinc as a potential anti-aging agent in age-related cellular signaling involving the NF-κB, A20, Nrf2, and p53 pathways.

MicroRNAs (miRNAs) are short non-coding RNAs that are recognized to epigenetically modulate gene expression by weakly binding to the 3′UTR and/or other sites of target mRNAs. A number of miRNAs have been recognized to be aberrantly expressed in cancer. These findings have led researchers to aggressively pursue miRNAs for cancer diagnostic and therapeutics. However, both identification and targeting of miRNAs is not very straight forward because each miRNA can modulate scores of different genes which in-turn can influence exponential number of different targets. In recent years, there has been a consensus that the complexity of miRNAs requires holistic systems biology approaches to tease out the specific targets of each miRNA, which appears to be context dependent. In this chapter we present the recent advancements in systems and network biology and how these and related technologies are aiding in the design of effective miRNA-based therapeutics against cancer.

Pancreatic cancer is one of the most malignant and aggressive forms of cancers that is not amenable to any of the available therapeutics. The vast majority of patients present with highly advanced or metastatic disease with no curative treatment options. Pancreatic cancer's low prognosis rate of five years post diagnosis has been mainly attributed to high metastasis rate and drug resistance. The molecular mechanisms underlying its aggressive nature are mostly unknown and under investigation. The completion of the human genome project at the turn of the century ushered in a new era in which researchers exploited genetic, epigenetic, and proteomic expression profiling methodologies in pancreatic cells, advanced animal models, and patient cohorts leading to a generation of unprecedented amount of datasets. Such analyses have allowed for the evaluations of pancreas samples at much greater molecular depths. However, these efforts have yet to yield any meaningful or tangible outcome. One of the primary reasons for such poor progress is that barring few isolated cases, most of these large-scale expression studies were performed with a reductionist view. The complexity of the disease requires holistic approaches that are expected to allow better understanding of the different components that drive heterogeneous pancreas tumors. In this chapter we highlight the importance of systems and network biology in pancreas cancer diagnostics, prevention, and therapy. We conclude with an example of how systems biology can be helpful in understanding pancreatic cancer heterogeneity, especially in the analyses of highly resistant pancreatic cancer stem-like cells.

MicroRNAs (miRNAs), often aberrantly expressed in cancer, have been implicated in the regulation of a number of critical cell survival pathways including the genes in the Kras signaling. Kras mutations are observed in more than half of cancers and its inhibition has been the focus of intense research for the past 30 years. However, Kras itself has proven to be non-druggable due in part to the absence of binding pockets for small molecule drugs. These hurdles resulted in researchers shifting their focus on targeting proteins downstream to Kras pathways. P21 activated kinase 4 (PAK4) belongs to the family of serine/threonine kinases comprising of 6 isoforms (PAK 1-6) and is considered as a key effector of Rho family of GTPases downstream of RAS. PAK4 controls critical processes such as cellular motility, proliferation and survival. Recently a number of small molecule PAK4 antagonists have been investigated in preclinical and clinical setting; albeit without any success. Emerging evidence shows that PAK is tightly regulated by a number of miRNAs that are also recognized to promote hyper-activation of oncogenic Kras signaling. Therefore, the understanding of the role of miRNAs in the regulation of PAK4 is critical to the development of therapies against this important player in the Kras pathway. Through this review, we bring forward mechanistic insights on PAK4 regulation by aberrantly expressed miRNAs in cancer and its implications on Kras signaling. We anticipate that enhanced knowledge of the miRNA-PAK4 interaction network will allow the development of successful therapies targeting this critical protein to ultimately rein in Kras.

It is widely accepted that cancers arise from cancer stem cells that possess self-renewal capacity and can recapitulate the tumors derived from it. However, the cellular origin of cancers is not clear. Emerging evidence is accumulating showing that cancers of distinct subtypes within an organ may derive from different “cell of origin.” Cancer stem cells may originate from long-lived normal stem cells, transit amplifying progenitor cells or more committed differentiated cells through different mechanisms by which cancer cells acquire unlimited self-renewal capacity. The identification of these crucial target cell populations may allow earlier detection for the prevention of malignancies, and it may also provide targets that could be exploited for eventual elimination of cancers with aggressive phenotype.

The p21-activated kinase 4 (PAK4) is a key downstream effector of the Rho family GTPases. PAK4 is found to be over-expressed in many oncogenic Ras-driven cancers and cell lines but not in their normal counterparts. Mesenchymal pancreatic ductal adenocarcinoma (PDAC) stem cells (CSCs) that are triple positive for stemness markers (CD133+, CD44+, and EpCam+) as well as Ras and snail transduced human mammary epithelial cells (HMLER-snail) showed enhanced expression of PAK4 along with activation of Rho, Rac1 and CDC42. PAK4 RNA interference resulted in disruption of PDAC CSC spheroids, reduction of mesenchymal markers (i.e. vimentin and snail) and suppression of CSCs potential to form subcutaneous tumors in mice. These findings point to a novel role of PAK4 in promoting oncogenic Ras-driven EMT and stemness. Using PDAC CSCs (MiaPaCa-2 and L3.6pl) and human mammary epithelial cells (HMECs) that are transduced with Ras and the EMT promoter snail (HMLE-Snail and HMLER-Snail), we investigated the impact of PAK4 allosteric modulators [PAMs (KPT-7189, KPT-7523, KPT-9274 and KPT-9307)] on the reversal of EMT and stemness. The toxicity and efficacy of PAMs were evaluated in vitro and in multiple sub-cutaneous xenograft models. PAMs show anti-proliferative activity in vitro against different PDAC CSCs and HMECs while sparing normal cells. Cell growth inhibition was concurrent with apoptosis induction, suppression of colony formation and reversal of mesenchymal morphology to epithelial (MET). PAMs not only reduced PAK4 RNA and protein steady state levels but also inhibited proliferative and anti-apoptotic signals downstream of PAK4. PAMs caused suppression of EMT markers (EpCAM, vimentin and snail) and re-expression of an epithelial promoter E-cadherin. PAM treatment inhibited RhoA, Rac1 and CDC42 activation in GLISA assays. KPT-9274 showed remarkable anti-tumor activity in sub-cutaneous xenograft models of CSCs and residual tumors showed suppression of EMT markers that was concurrent with inhibition of PAK4 signaling. These studies open a novel therapeutic opportunity against EMT and cancer stem cells through PAK4 inhibition. Citation Format: Asfar S. Azmi, Irfana Muqbil, Amro Aboukameel, William Senapedis, Erkan Baloglu, Yosef Landesman, Sharon Shacham, Michael Kauffman, Philip A. Philip, Ramzi M. Mohammad. The role of p21-activated kinase 4 (PAK4) in cancer stemness and epithelial-to-mesenchymal transition. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1873.