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Cachexia is an acute syndrome that is very commonly observed in patients with cancer. Cachexia is the number one cause of death in patients with metastatic disease and is also the major factor for physical toxicity and financial burden. More importantly, the majority of patients with advanced-stage pancreatic ductal adenocarcinoma (PDAC) cancer undergo cachexia. Pancreatic cancer causes deaths of ∼50,000 Americans and about 400,000 people worldwide every year. The high mortality rates in metastatic PDAC are due to systemic pathologies and cachexia, which quickens death in these patients. About 90% of all patients with PDAC undergo wasting of muscle causing mobility loss and leading to a number of additional pathological conditions. PDAC-associated cancer cachexia emanates from complex signaling cues involving both mechanical and biological signals. Tumor invasion is associated with the loss of pancreatic function-induced digestive disorders and malabsorption, which causes subsequent weight loss and eventually promotes cachexia. Besides, systemic inflammation of patients with PDAC could release chemical cues (e.g., cytokine-mediated Atrogin-1/MAFbx expression) that participate in muscle wasting. Our understanding of genes, proteins, and cytokines involved in promoting cancer cachexia has evolved considerably. However, the role of epigenetic factors, particularly the role of noncoding RNAs (ncRNAs) in regulating PDAC-associated cachexia is less studied. In this review article, the most updated knowledge on the various ncRNAs including microRNAs (miRs), long noncoding RNA (lncRNAs), piwi interacting RNAs (PiwiRNAs), small nucleolar RNA (snoRNAs), and circular RNAs (circRNA) and their roles in cancer cachexia are described.

Supplementary Figure 1. XPO1-KRAS synthetic lethal interaction identified using the Slorth database. Supplementary Figure 2. KRAS WT, KRAS G12D and KRAS G12V MEF cell lines were refractory to growth inhibition by selinexor or MRTX1257 or their combinations. Supplementary Figure 3. KRAS G12D mutant PDAC cell line Panc-1 was refractory to growth inhibition by KRAS G12C inhibitor AMG510. Supplementary Figure 4. Body weights of mice xenografted with MiaPaCa2 tumors were measured during the treatment period. Supplementary Table 1. Sequences of primers used. Supplementary Table 2. Combination Index (CI) values at various dose combinations of the drugs tested on different KRAS G12C mutant cell lines.

The identification of molecules that can bind covalently to KRAS G12C and lock it in an inactive GDP-bound conformation has opened the door to targeting KRAS G12C selectively. These agents have shown promise in preclinical tumor models and clinical trials. FDA has recently granted approval to sotorasib for KRAS G12C–mutated non–small cell lung cancer (NSCLC). However, patients receiving these agents as monotherapy generally develop drug resistance over time. This necessitates the development of multi-targeted approaches that can potentially sensitize tumors to KRAS inhibitors. We generated KRAS G12C inhibitor–resistant cell lines and observed that they exhibit sensitivity toward selinexor, a selective inhibitor of nuclear export protein exportin 1 (XPO1), as a single agent. KRAS G12C inhibitors in combination with selinexor suppressed the proliferation of KRAS G12C–mutant cancer cell lines in a synergistic manner. Moreover, combined treatment of selinexor with KRAS G12C inhibitors resulted in enhanced spheroid disintegration, reduction in the number and size of colonies formed by G12C-mutant cancer cells. Mechanistically, the combination of selinexor with KRAS G12C inhibitors suppressed cell growth signaling and downregulated the expression of cell-cycle markers, KRAS and NF-κB as well as increased nuclear accumulation of tumor suppressor protein Rb. In an in vivo KRAS G12C cell-derived xenograft model, oral administration of a combination of selinexor and sotorasib was demonstrated to reduce tumor burden and enhance survival. In conclusion, we have shown that the nuclear transport protein XPO1 inhibitor can enhance the anticancer activity of KRAS G12C inhibitors in preclinical cancer models.Significance:In this study, combining nuclear transport inhibitor selinexor with KRAS G12C inhibitors has resulted in potent antitumor effects in preclinical cancer models. This can be an effective combination therapy for patients with cancer that do not respond or develop resistance to KRAS G12C inhibitor treatment.

Supplementary Figure1. IC50 analysis for PAM activity across a panel of cell lines. MTT assay was performed at 72 hrs; Supplementary Figure 2. PDAC cell lines were grown at a density of 50,000 cells per well overnight and exposed to PAMs (at 5000 nM for 96 hrs). Apoptosis analysis was performed using Annexin V FITC assay; Supplementary Figure 3. Impact of PAK4 siRNA silencing on the activity of PAMs; Supplementary Figure 4. PAMs induce cancer cell selective cell cycle arrest; Supplementary Figure 5. PAMs suppress PDAC cellular migration; Supplementary Figure 6. DU145 prostate cancer cell line were grown in 100 mm petri dish overnight; Supplementary Figure 7: Flow sorted MiaPaCa-2 CSCs (CD44CD133EpCAM+++) as described in methods section were grown in six well plates at a density of 50,000 cells per well and exposed to 5 μM concentration of PAMs for 72 hrs; Supplementary Figure 8. PAMs molecularly synergize with gemcitabine and oxaliplatin; Supplementary Figure 9. Single agent and combination anti-tumor activity of PAM in sub-cutaneous PDAC tumor models.

Metastatic pancreatic neuroendocrine tumors (PNET) remain an unmet clinical problem. Chronologic treatment in PNETs includes observation (watchful protocol), surgery, targeted therapy, and chemotherapy. However, increasing evidence illustrates that the outcomes of targeted therapeutic options for the treatment of advanced PNETs show minimal response. The FDA-approved mTOR inhibitor everolimus does not shrink these tumors. It only delays disease progression in a subset of patients, while a significant fraction acquires resistance and shows disease progression. Thus, there is a need for more effective targeted approaches to sensitize PNETs to everolimus for better treatment outcomes. Previously, we showed that mTOR regulator p21 activated kinase 4 (PAK4) and nicotinamide adenine dinucleotide biosynthesis enzyme nicotinamide phosphoribosyl transferase (NAMPT) were aberrantly expressed in PNET tissue and promoted everolimus resistance. In this report, we demonstrate that PAK4-NAMPT dual inhibitor KPT-9274 can synergize with everolimus (growth inhibition, colony suppression, and glucose uptake assays). KPT-9274-everolimus disrupted spheroid formation in multiple PNET models. Molecular analysis showed alteration of mTORC2 through downregulation of RICTOR as a mechanism supporting synergy with everolimus in vitro. KPT-9274 suppressed β-catenin activity via inhibition of PAK4, highlighting the cross-talk between Rho GTPases and Wnt signaling in PNETs. KPT-9274, given at 150 mg/kg in combination with sub-MTD everolimus (2.5 mg/kg), significantly suppressed two PNET-derived xenografts. These studies bring forward a well-grounded strategy for advanced PNETs that fail to respond to single-agent everolimus.

PDF - 3347KB, Synthesis and characterization of the lead compound 1 (UMI-59) and its analog 2 (UMI-77), additional details for used methods, and nine supplementary figures.

Supplementary Figures

Pancreatic cancer is the fourth leading cause of cancer-related deaths in the United States, which is, in part, due to intrinsic (de novo) and extrinsic (acquired) resistance to conventional therapeutics, suggesting that innovative treatment strategies are required for overcoming therapeutic resistance to improve overall survival of patients. Oral administration of metformin in patients with diabetes mellitus has been reported to be associated with reduced risk of pancreatic cancer and that metformin has been reported to kill cancer stem cells (CSC); however, the exact molecular mechanism(s) has not been fully elucidated. In the current study, we examined the effect of metformin on cell proliferation, cell migration and invasion, and self-renewal capacity of CSCs and further assessed the expression of CSC marker genes and microRNAs (miRNA) in human pancreatic cancer cells. We found that metformin significantly decreased cell survival, clonogenicity, wound-healing capacity, sphere-forming capacity (pancreatospheres), and increased disintegration of pancreatospheres in both gemcitabine-sensitive and gemcitabine-resistant pancreatic cancer cells. Metformin also decreased the expression of CSC markers,CD44, EpCAM,EZH2, Notch-1, Nanog and Oct4, and caused reexpression of miRNAs (let-7a,let-7b, miR-26a, miR-101, miR-200b, and miR-200c) that are typically lost in pancreatic cancer and especially in pancreatospheres. We also found that reexpression of miR-26a by transfection led to decreased expression of EZH2 and EpCAM in pancreatic cancer cells. These results clearly suggest that the biologic effects of metformin are mediated through reexpression of miRNAs and decreased expression of CSC-specific genes, suggesting that metformin could be useful for overcoming therapeutic resistance of pancreatic cancer cells. Cancer Prev Res; 5(3); 355–64. ©2011 AACR.

Using a high-throughput screening (HTS) approach, we have identified and validated several small-molecule Mcl-1 inhibitors (SMI). Here, we describe a novel selective Mcl-1 SMI inhibitor, 2 (UMI-77), developed by structure-based chemical modifications of the lead compound 1 (UMI-59). We have characterized the binding of UMI-77 to Mcl-1 by using complementary biochemical, biophysical, and computational methods and determined its antitumor activity against a panel of pancreatic cancer cells and an in vivo xenograft model. UMI-77 binds to the BH3-binding groove of Mcl-1 with Ki of 490 nmol/L, showing selectivity over other members of the antiapoptotic Bcl-2 family. UMI-77 inhibits cell growth and induces apoptosis in pancreatic cancer cells in a time- and dose-dependent manner, accompanied by cytochrome c release and caspase-3 activation. Coimmunoprecipitation experiments revealed that UMI-77 blocks the heterodimerization of Mcl-1/Bax and Mcl-1/Bak in cells, thus antagonizing the Mcl-1 function. The Bax/Bak-dependent induction of apoptosis was further confirmed using murine embryonic fibroblasts that are Bax- and Bak-deficient. In an in vivo BxPC-3 xenograft model, UMI-77 effectively inhibited tumor growth. Western blot analysis in tumor remnants revealed enhancement of proapoptotic markers and significant decrease of survivin. Collectively, these promising findings show the therapeutic potential of Mcl-1 inhibitors against pancreatic cancer and warrant further preclinical investigations. Mol Cancer Ther; 13(3); 565–75. ©2013 AACR.

Novel targeted therapeutics alone or in rational combinations are likely to dominate the future management of various hematological neoplasms. However, the challenges currently faced are the molecular heterogeneity in driver lesions and genetic plasticity leading to multiple resistance pathways. Thus, progress has overall been gradual. For example, despite the advent of targeted agents against actionable drivers like FLT3 in acute myeloid leukemia (AML), the prognosis remains suboptimal in newly diagnosed and dismal in the relapsed/refractory (R/R) setting, due to other molecular abnormalities contributing to inherent and acquired treatment resistance. Nuclear export inhibitors are of keen interest because they can inhibit several active tumorigenic processes simultaneously and also synergize with other targeted drugs and chemotherapy. XPO1 (or CRM1, chromosome maintenance region 1) is one of the most studied exportins involved in transporting critical cargoes, including tumor suppressor proteins like p27, p53, and RB1. Apart from the TSP cargo transport and its role in drug resistance, XPO1 inhibition results in retention of master transcription factors essential for cell differentiation, cell survival, and autophagy, rendering cells more susceptible to the effects of other antineoplastic agents, including targeted therapies. This review will dissect the role of XPO1 inhibition in hematological neoplasms, focusing on mechanistic insights gleaned mainly from work with SINE compounds. Future potential combinatorial strategies will be discussed.

Purpose:Pancreatic ductal adenocarcinoma (PDAC) remains a deadly disease urgently requiring new treatments. Overexpression of the protein transporter exportin-1 (XPO1) leads to mislocalization of tumor-suppressor proteins (TSP) and their inactivation. Earlier, we showed that blocking XPO1 by CRISPR/Cas9 validated Selective Inhibitor of Nuclear Export (SINE) compounds (selinexor and analogs) restores the antitumor activity of multiple TSPs leading to suppression of PDAC in vitro and in orthotopic models.Experimental Design:We evaluate the synergy between SINE compounds and standard-of-care treatments in preclinical models and in a PDAC Phase Ib trial.Results:SINE compounds synergize with gemcitabine (GEM) and nanoparticle albumin–bound (nab)-paclitaxel leading to suppression of PDAC cellular growth and cancer stem cell (CSC) spheroids disintegration. Label-free quantitative proteome profiling with nuclear and cytoplasmic enrichment showed superior enhancement in nuclear protein fraction in combination treatment. Selinexor inhibited the growth of PDAC CSC and two patient-derived (PDX) subcutaneous xenografts. Selinexor–GEM–nab-paclitaxel blocked PDX and orthotopic tumor growth. In a phase 1b study (NCT02178436), 9 patients were exposed to selinexor (60 mg oral) with GEM (1,000 mg/m2 i.v.) and nab-paclitaxel (125 mg/m2 i.v.) on days 1, 8, and 15 of 28-day cycle. Two patients showed partial response, and 2 had stable disease. An outstanding, durable objective response was observed in one of the responders with progression-free survival of 16 months and overall survival of 22 months.Conclusions:Our preclinical and ongoing clinical study lends support to the use of selinexor–GEM–nab-paclitaxel as an effective therapy for metastatic PDAC.

Supplementary Figure

Purpose:The nuclear exporter protein exportin-1 (XPO1) is overexpressed in non-Hodgkin lymphoma (NHL) and correlates with poor prognosis. We evaluated enhancing R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) activity in NHL by targeted inhibition of XPO1 using the selective inhibitor of nuclear export (SINE) compounds.Patients and Methods:We evaluated the antitumor activity of SINE compounds in combination with CHO chemotherapy in vitro and in vivo. Newly diagnosed NHL patients in a phase I dose-escalation study received R-CHOP for 6 cycles with weekly selinexor (60, 80, and 100 mg), then selinexor maintenance therapy for one year. RT-PCR, Western blotting, and RNA sequencing were performed on patient blood samples.Results:SINE compounds synergized with CHO in vitro in NHL cell lines and in vivo in our murine xenograft model. In our phase I study, selinexor was dosed at 60 mg (n = 6) and 80 mg (n = 6). The most common adverse events (AE) among 12 patients were fatigue (67%) and nausea (100%). Grade 3–4 AEs were infrequent. Ten evaluable patients had an overall response rate of 100% and complete remission rate of 90% with sustained remissions (median follow-up: 476 days). Maximally tolerated dose was not reached; however, the recommended phase II dose was 60 mg selinexor weekly after evaluating tolerability and discontinuation rates for each dose cohort. Analysis of patient blood samples revealed downregulation of XPO1 and several prosurvival markers.Conclusions:SINE compounds enhance the activity of CHO in vitro and in vivo. Selinexor in combination with R-CHOP was generally well tolerated and showed encouraging efficacy in NHL (NCT03147885).

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KRASG12C inhibitors have revolutionized the treatment landscape for cancer patients harboring the G12C mutant isoform of KRAS. With the recent FDA approval of sotorasib and adagrasib, patients now have access to more promising treatment options. However, patients who receive these agents as a monotherapy usually develop drug resistance. Thus, there is a need to develop logical combination strategies that can delay or prevent the onset of resistance and simultaneously enhance the antitumor effectiveness of the treatment regimen. In this study, we aimed at pharmacologically targeting PAK4 by KPT9274 in combination with KRASG12C inhibitors in KRASG12C mutant pancreatic ductal adenocarcinoma (PDAC) and non–small cell lung cancer (NSCLC) preclinical models. PAK4 is a hub molecule that links several major signaling pathways and is known for its tumorigenic role in mutant Ras-driven cancers. We assessed the cytotoxicity of PAK4 and KRASG12C inhibitors combination in KRASG12C mutant 2D and 3D cellular models. KPT9274 synergized with both sotorasib and adagrasib in inhibiting the growth of KRASG12C mutant cancer cells. The combination was able to reduce the clonogenic potential of KRASG12C mutant PDAC cells. We also evaluated the antitumor activity of the combination in a KRASG12C mutant PDAC cell line-derived xenograft (CDX) model. Oral administration of a sub-optimal dose of KPT9274 in combination with sotorasib (at one-fourth of MTD) demonstrated significant inhibition of the tumor burden (p= 0.002). Similarly, potent antitumor efficacy was observed in an NSCLC CDX model where KPT9274, acting as an adjuvant, prevented tumor relapse following the discontinuation of sotorasib treatment (p= 0.0001). KPT9274 and sotorasib combination also resulted in enhanced survival. This is the first study showing that KRASG12C inhibitors can synergize with PAK4 inhibitor KPT9274 bothin vitroandin vivoresulting in remarkably enhanced antitumor activity and survival outcomes.SignificanceKRASG12C inhibitors demonstrate limited durable response in patients with KRASG12C mutations. In this study, combining PAK4 inhibitor KPT9274 with KRASG12C inhibitors has resulted in potent antitumor effects in preclinical cancer models of PDAC and NSCLC. Our results bring forward a novel combination therapy for cancer patients that do not respond or develop resistance to KRASG12C inhibitor treatment.

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.

Gastrointestinal stromal tumors (GIST) are rare neoplasms arising from the interstitial cell of Cajal in the gastrointestinal tract. Two thirds of GIST in adult patients have c-Kit mutation and smaller fractions have platelet derived growth factor receptor alpha (PDGFRA) mutation. Surgery is the only curative treatment for localized disease. Imatinib improves survival when used adjuvantly and in advanced disease. Several targeted therapies have also improved survival in GIST patients after progression on imatinib including sunitinib and regorafenib. Recently, United States Federal and Drug Administration (FDA) approved two new tyrosine kinase inhibitors for the treatment of heavily pretreated advanced/unresectable GIST including avapritinib (a selective inhibitor for PDGFRA exon 18 mutation including D842V mutations) and ripretinib (a broad-spectrum kinase inhibitor of c-Kit and PDGFRA). In this article, we will provide a comprehensive review of GIST including the current standard of care treatment and exploring future paradigm shifts in therapy.

Purpose: The nuclear exporter protein exportin-1 (XPO1) is overexpressed in non-Hodgkin lymphoma (NHL) and correlates with poor prognosis. We evaluated enhancing R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) activity in NHL by targeted inhibition of XPO1 using the selective inhibitor of nuclear export (SINE) compounds. Patients and Methods: We evaluated the antitumor activity of SINE compounds in combination with CHO chemotherapy in vitro and in vivo. Newly diagnosed NHL patients in a phase I dose-escalation study received R-CHOP for 6 cycles with weekly selinexor (60, 80, and 100 mg), then selinexor maintenance therapy for one year. RT-PCR, Western blotting, and RNA sequencing were performed on patient blood samples. Results: SINE compounds synergized with CHO in vitro in NHL cell lines and in vivo in our murine xenograft model. In our phase I study, selinexor was dosed at 60 mg (n = 6) and 80 mg (n = 6). The most common adverse events (AE) among 12 patients were fatigue (67%) and nausea (100%). Grade 3–4 AEs were infrequent. Ten evaluable patients had an overall response rate of 100% and complete remission rate of 90% with sustained remissions (median follow-up: 476 days). Maximally tolerated dose was not reached; however, the recommended phase II dose was 60 mg selinexor weekly after evaluating tolerability and discontinuation rates for each dose cohort. Analysis of patient blood samples revealed downregulation of XPO1 and several prosurvival markers. Conclusions: SINE compounds enhance the activity of CHO in vitro and in vivo. Selinexor in combination with R-CHOP was generally well tolerated and showed encouraging efficacy in NHL (NCT03147885).

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.

Transcription factors (TFs) are essential for proper activation of gene during the process of organogenesis, differentiation, lineage specificity. Reactivation or dysregulation of TFs regulatory networks could lead to deformation of organs, diseases including various malignancies. Currently, understanding the mechanism of oncogenesis became a necessity for the development of targeted therapeutic strategy for different cancer types. It is evident that many TFs go awry in cancers of the pancreas such as pancreatic ductal adenocarcinoma (PDAC) and pancreatic neuroendocrine neoplasms (PanNENs). These mutated or dysregulated TFs abnormally controls various signaling pathways in PDAC and PanNENs including RTK, PI3K-PTEN-AKT-mTOR, JNK, TGF-β/SMAD, WNT/β-catenin, SHH, NOTCH and VEGF which in turn regulate different hallmarks of cancer. Aberrant regulation of such pathways have been linked to the initiation, progression, metastasis, and resistance in pancreatic cancer. As of today, a number of TFs has been identified as crucial regulators of pancreatic cancer and a handful of them shown to have potential as therapeutic targets in pre-clinical and clinical settings. In this review, we have summarized the current knowledge on the role and therapeutic usefulness of TFs in PDAC and PanNENs.

The identification of molecules that can bind covalently to KRAS G12C and lock it in an inactive GDP-bound conformation has opened the door to targeting KRAS G12C selectively. These agents have shown promise in preclinical tumor models and clinical trials. FDA has recently granted approval to sotorasib for KRAS G12C–mutated non–small cell lung cancer (NSCLC). However, patients receiving these agents as monotherapy generally develop drug resistance over time. This necessitates the development of multi-targeted approaches that can potentially sensitize tumors to KRAS inhibitors. We generated KRAS G12C inhibitor–resistant cell lines and observed that they exhibit sensitivity toward selinexor, a selective inhibitor of nuclear export protein exportin 1 (XPO1), as a single agent. KRAS G12C inhibitors in combination with selinexor suppressed the proliferation of KRAS G12C–mutant cancer cell lines in a synergistic manner. Moreover, combined treatment of selinexor with KRAS G12C inhibitors resulted in enhanced spheroid disintegration, reduction in the number and size of colonies formed by G12C-mutant cancer cells. Mechanistically, the combination of selinexor with KRAS G12C inhibitors suppressed cell growth signaling and downregulated the expression of cell-cycle markers, KRAS and NF-κB as well as increased nuclear accumulation of tumor suppressor protein Rb. In an in vivo KRAS G12C cell-derived xenograft model, oral administration of a combination of selinexor and sotorasib was demonstrated to reduce tumor burden and enhance survival. In conclusion, we have shown that the nuclear transport protein XPO1 inhibitor can enhance the anticancer activity of KRAS G12C inhibitors in preclinical cancer models. Significance: In this study, combining nuclear transport inhibitor selinexor with KRAS G12C inhibitors has resulted in potent antitumor effects in preclinical cancer models. This can be an effective combination therapy for patients with cancer that do not respond or develop resistance to KRAS G12C inhibitor treatment.

Transcription factors are a group of proteins, which possess DNA-binding domains, bind to DNA strands of promoters or enhancers, and initiate transcription of genes with cooperation of RNA polymerase and other co-factors. They play crucial roles in regulating transcription during embryogenesis and development. Their physiological status in different cell types is also important to maintain cellular homeostasis. Therefore, any deregulation of transcription factors will lead to the development of cancer cells and tumor progression. Based on their functions in cancer cells, transcription factors could be either oncogenic or tumor suppressive. Furthermore, transcription factors have been shown to modulate cancer stem cells, epithelial-mesenchymal transition (EMT) and drug response; therefore, measuring deregulated transcription factors is hypothesized to predict treatment outcomes of patients with cancers and targeting deregulated transcription factors could be an encouraging strategy for cancer therapy. Here, we summarize the current knowledge of major deregulated transcription factors and their effects on causing poor clinical outcome of patients with cancer. The information presented here will help to predict the prognosis and drug response and to design novel drugs and therapeutic strategies for the treatment of cancers by targeting deregulated transcription factors.

Background: All patients with pancreatic ductal adenocarcinoma (PDAC) experience disease progression after gemcitabine-nab-paclitaxel (GemPac) treatment with a median time to progression of just under 6 months. There is an urgent need for more effective combination therapies for this highly recalcitrant disease. Previously we showed that the selective inhibitor of nuclear export (SINE) selinexor (Sel) against XPO1 in combination with GemPac enhanced the survival of LSL-Kras G12D/+; Trp53 fl/+; Pdx1-Cre (KPC) mice. The Sel-GemPac combination also showed evaluable response in PDAC patients in a Phase I study. Here we identified key regulatory molecules involved in the synergy of the Sel-GemPac combination, utilizing KPC mouse tumors and patient biopsy samples. We also evaluated the efficacy of this combination in a Phase II study. Methods: The activity of Sel-GemPac was evaluated in KPC mouse derived 2D cell line and 3D spheroid models. RNA-seq was performed to evaluate transcriptional differences associated with synergy. The identified differentially expressed genes (DEG) were validated in vitro through siRNA mediated silencing, qPCR, cytotoxicity, and related assays. The molecular mechanism of synergy was also evaluated in KPC mice tumors and in biopsies from patients enrolled in the Phase I portion of the trial using spatial transcriptomic and proteomic analysis. The efficacy of Sel-Gem was evaluated in a Phase II study in patients with metastatic PDAC (NCT02178436). Results: In a KPC tumor derived cell line, Sel inhibited cell growth and suppressed spheroid formation. Sel synergized with GemPac (CI Conclusions: Collectively, our studies show that XPO1 may be a valid therapeutic target in PDAC and Sel-GemPac is a combination warranting further investigation. Citation Format: Md. Hafiz Uddin, Sahar F. Bannoura, Husain Y. Khan, Amro Aboukameel, Yiwei Li, Ibrahim Azar, Eliza W. Bael, Miguel Tobon, Donald Weaver, Steve Kim, Tanya Odisho, Amr Mohammed, Gregory Dyson, Rafic Beydoun, Ramzi M. Mohammad, Herbert Chen, Bassel El-Rayes, Philip A. Philip, Mohammad N. Al-Hallak, Asfar S. Azmi. Identification of key regulators for nuclear protein export inhibitor and chemotherapy combination in pancreatic cancer using spatial genomics approach [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB299.

The majority of pancreatic ductal adenocarcinoma (PDAC) patients experience disease progression while on treatment with gemcitabine and nab-Paclitaxel (GemPac) treatment indicating the need for more effective combinations for this recalcitrant disease.Earlier we showed that nuclear exporter protein exportin 1 (XPO1) is a valid therapeutic target in PDAC and the selective inhibitor of nuclear export (SINE) selinexor (Sel), synergistically enhances the efficacy of GemPac in pancreatic cancer cells, spheroids, patient derived tumors and had promising activity in a phase I study in patients with PDAC. Here we investigated the mechanisms of synergy by molecular profiling of Sel or Sel-GemPac treated PDAC cells, in vitro and by utilizing genetically modified LSL-Kras G12D/+; Trp53 fl/+; Pdx1-Cre (KPC) mouse model.In KPC model, Sel given with GemPac at a sub-MTD dose enhanced the survival compared to controls (p < 0.05). Molecular analysis of residual KPC tumors showed re-organization of tumor stromal architecture, suppression of proliferation and nuclear retention of tumor suppressors. Single cell nuclear RNA sequencing (snRNAseq) revealed significant loss of cellular clusters in the Sel-GemPac treated mice including CD44 stem cell population. RNA-seq, Gene Ontology (GO) and Gene Set Enrichment Analysis (GSEA) analysis showed inhibition of several tumor promoting molecules.Prioritized RNA-seq identified molecules were validated in in vitro or in the PDAC patient samples through siRNA mediated silencing, quantitative gene expression, cytotoxicity assays and confirmed their role in observed synergy. Sel or Sel-GemPac caused broad penetration in PDAC supporting signaling networks.

Pancreatic cancer is a deadly disease that is increasing in incidence throughout the world. There are no clear causal factors associated with the incidence of pancreatic cancer; however, some correlation to smoking, diabetes and alcohol has been described. Recently, a few studies have linked the human microbiome (oral and gastrointestinal tract) to pancreatic cancer development. A perturbed microbiome has been shown to alter normal cells while promoting cancer-related processes such as increased cell signaling, immune system evasion and invasion. In this article, we will review in detail the alterations within the gut and oral microbiome that have been linked to pancreatic cancer and explore the ability of other microbiomes, such as the lung and skin microbiome, to contribute to disease development. Understanding ways to identify a perturbed microbiome can result in advancements in pancreatic cancer research and allow for prevention, earlier detection and alternative treatment strategies for patients.

TPS760 Background: Local tumor progression is a cause of significant mortality and morbidity in patients with unresectable pancreatic ductal adenocarcinoma (PDAC). Effective approaches to achieve durable local control are urgently needed. Metabolic reprogramming and enhanced mitochondrial function, both hallmarks of PDAC, are known contributors to chemo- and radio-resistance. CPI-613, a lipoic acid analog that selectively inhibits components of the Krebs cycle in tumors, showed promising preclinical synergy in combination with gemcitabine and radiation therapy (gem-RT). Methods: We describe a single-arm, single-center, open-label, phase I study designed to determine the maximum tolerated dose of CPI-613 when used concomitantly with gemcitabine and intensity modulated radiation therapy (IMRT) for local control of PDAC. CPI-613 will be administered once weekly by intravenous infusion over approximately 2 hours at a starting dose of 500 mg/m2 and dose-escalated/de-escalated using a Bayesian optimal interval design. Gemcitabine will be given once weekly at 400 mg/m2 dosage and IMRT as 54 Gray (Gy) in 30 fractions (1.8 Gy per fraction) with five fractions given per week. Up to 24 patients will be enrolled for the study after meeting the following main eligibility criteria, which include: pathologically confirmed PDAC; inoperable disease that by institutional pancreatic multidisciplinary tumor board or multidisciplinary review are considered to benefit from definitive local control of the primary tumor; ECOG of 0-2; and adequate organ and marrow function after completion of intended systemic chemotherapy. The secondary objectives are to determine the recommended phase II dose of CPI-613 when used with gem-RT, safety and tolerability of CPI-613-gem-RT, overall survival, local progression-free survival (PFS), overall PFS, patient-reported quality of life after treatment, and late gastrointestinal toxicities following treatment with CPI-613-gem-RT. Clinical trial information: NCT05325281 . Support: Cornerstone Pharmaceuticals. [Table: see text]

649 Background: The mTOR inhibitor, Everolimus (EVE), is FDA-approved for the treatment of advanced PNENs on the basis of delay of progression. The RADIANT-3 trial showed an increase in PFS from 4.6 to 11 months compared to placebo with an ORR of only 5%. Prior studies suggest that targeting the aberrant expression of mTOR regulators p21 activated kinase 4 (PAK4) and nicotinamide adenine dinucleotide biosynthesis enzyme nicotinamide phosphoribosyltransferase (NAMPT) in PNENs sensitizes these tumors to EVE. To further qualify these observations, we queried a large real-world dataset of PNENs, characterizing the molecular and immune landscapes, as well as the clinical outcomes associated with aberrant PAK4 and NAMPT expression. Methods: 294 cases of PNENs were analyzed using Next Generation Sequencing (NextSeq) and Whole Exome and Whole Transcriptome Sequencing (NovaSeq) at Caris Life Sciences (Phoenix, AZ). For our analyses, we stratified our study cohort into four groups based on the median expression of PAK4 and NAMPT: PAK4-low/NAMPT-low, PAK4-low/NAMPT-high, PAK4-high/NAMPT-low and PAK4-high/NAMPT-high. Significance was determined using chi-square, Fisher-Exact or Mann-Whitney U, and p-values were adjusted for multiple comparisons (q < 0.05). Results: High prevalence of mutations in PTEN (10.71% vs 1.18%; p < 0.05, q > 0.05), a tumor suppressor of the mTOR pathway and high expression of genes activated in response to mTOR activation such as SLC2A1 (3.07-fold), PFKP (3.32-fold), SCD (2.70-fold), MVK (2.92-fold) and G6PD (2.58-fold) were observed in PAK4-high/NAMPT-high compared to the PAK4-low/NAMPT-low tumors (all q < 0.05). A congruent enrichment of PI3K/AKT/mTOR and glycolysis pathways by single-sample gene set enrichment analysis was observed in these tumors (all q < 0.05). When querying the immune landscape, we observed enrichment in inflammatory response, IL6/JAK/STAT3, IL2/STAT5 signaling pathways and immune checkpoint genes such as PDCD1 (5.14-fold), CD274 (2.84-fold), PDCD1LG2 (2.44-fold), CD80 (3.00-fold), CD86 (2.82-fold), IDO1 (1.92-fold), LAG3 (3.09-fold), HAVCR2 (2.66-fold) and CTLA4 (4.49-fold) in the PAK4-high/NAMPT-high tumors (all q < 0.05). Immune cell infiltration estimates revealed an increase in Neutrophils, NK cells and Tregs in the PAK4-high/NAMPT-high tumors (p < 0.05, q > 0.05). Conclusions: Our study demonstrates that PAK4-high/NAMPT-high PNENs are associated with distinct molecular and immune profiles. While the dual blockade of PAK4 and NAMPT has been reported to enhance the efficacy of EVE in PNENs, whether such a blockade would enhance the efficacy of immunotherapeutics warrants further investigation.

Simple Summary Non-Hodgkin’s lymphomas (NHL) are cancers of the white blood cells. While some NHL subtypes, such as Diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL), grow and spread aggressively, others, like follicular lymphoma (FL), are indolent in nature. Irrespective of how fast they grow, all NHL subtypes can spread to other organs in the body if not treated. In this study, we have demonstrated that the targeted inhibition of p21-activated kinase 4 (PAK4) and nicotinamide phosphoribosyl transferase (NAMPT) in different NHL subtypes by a novel, orally bioavailable, dual inhibitor KPT-9274 can lead to energy depletion, inhibition of cell proliferation, and ultimately apoptosis. KPT-9274 treatment shows potent anti-tumor effects in DLBCL and MCL subcutaneous xenograft models and enhances mice survival in a systemic FL model. Therefore, this study demonstrates the potential of targeting PAK4 and NAMPT by a small molecule inhibitor KPT-9274 for NHL therapy. Abstract Diffuse large B-cell lymphoma (DLBCL), grade 3b follicular lymphoma (FL), and mantle cell lymphoma (MCL) are aggressive non-Hodgkin’s lymphomas (NHL). Cure rates are suboptimal and novel treatment strategies are needed to improve outcomes. Here, we show that p21-activated kinase 4 (PAK4) and nicotinamide phosphoribosyl transferase (NAMPT) is critical for lymphoma subsistence. Dual targeting of PAK4-NAMPT by the Phase I small molecule KPT-9274 suppressed cell proliferation in DLBCL, FL, and MCL. Growth inhibition was concurrent with apoptosis induction alongside activation of pro-apoptotic proteins and reduced pro-survival markers. We observed NAD suppression, ATP reduction, and consequent cellular metabolic collapse in lymphoma cells due to KPT-9274 treatment. KPT-9274 in combination with standard-of-care chemotherapeutics led to superior inhibition of cell proliferation. In vivo, KPT-9274 could markedly suppress the growth of WSU-DLCL2 (DLBCL), Z-138, and JeKo-1 (MCL) sub-cutaneous xenografts, and a remarkable increase in host life span was shown, with a 50% cure of a systemic WSU-FSCCL (FL) model. Residual tumor analysis confirmed a reduction in total and phosphorylated PAK4 and activation of the pro-apoptotic cascade. This study, using various preclinical experimental models, demonstrates the therapeutic potential of targeting PAK4-NAMPT in DLBCL, FL, and MCL. The orally bioavailable, safe, and efficacious PAK4-NAMPT dual inhibitor KPT-9274 warrants further clinical investigation.

Pancreatic adenocarcinoma (PDAC) is a devastating malignancy. There have been few advances that have substantially improved overall survival in the past several years. On its current trajectory, the deaths from PDAC are expected to cross that from all gastrointestinal cancers combined by 2030. Radiation therapy is a technically very complex modality that bridges multiple different treatment strategies. It represents a hybrid amongst advanced diagnostic imaging, local (often ablative) intervention, heterogenous biological mechanisms contributing to normal and oncologic cell kill. In this article we bring an overview of the several promising strategies that are currently being investigated to improve outcomes using radiation therapy for patients with pancreatic adenocarcinoma.

Kirsten rat sarcoma viral oncogene homolog (KRAS) is a proto-oncogene of the RAS-MAPK pathway. KRAS mutations are present in a variety of malignancies including lung, colorectal, and pancreatic cancer. Until the recent approval of sotorasib, a KRAS G12C inhibitor, lack of targeted therapy for KRAS has resulted in poor prognosis of patients with tumors harboring KRAS mutations. While the conditional approval of sotorasib was a major breakthrough for those patients harboring KRAS G12C mutations, G12C only accounts for a fraction of those with KRAS mutations and eventual resistance to G12C inhibitors are unavoidable. This comprehensive review on KRAS inhibitors covers accumulating evidence on not only the G12C inhibitors but also other therapeutic attempts to tackle KRAS including combination therapy as well as direct inhibition with vaccines, adoptive T cell therapy, proteolysis-targeted chimeras (PROTACs) and CRISPR/Cas9.