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Pancreatic cancer (PC) is a deadly disease that is intractable to currently available treatment regimens. Although well described in different tumors types, the importance of apoptosis inducer prostate apoptosis response-4 (Par-4) in PC has not been appreciated. PC is an oncogenic kras driven disease, which is known to downregulate Par-4. Therefore, this review highlights its significance and builds a strong case supporting the role of Par-4 as a possible therapeutic target in PC.Literature-based evidence spanning the last 15 years on Par-4 and its significance in PC.This review provides comprehensive knowledge of the significance of Par-4 and its association with kras status in PC, along with the crosstalk with crucial resistance and survival molecules NF-kappaB and Bcl-2 that ultimately are responsible for the overall poor outcome of different therapeutic approaches in this disease.Par-4 holds promise as a potential therapeutic target that can be induced by chemopreventive agents and small-molecule inhibitors either alone or in combination with standard chemotherapeutics leading to selective apoptosis in PC cells. It also acts as a chemosensitizer and therefore warrants further clinical investigations in this disease.

Plant polyphenols are important components of human diet, and a number of them are considered to possess chemopreventive and therapeutic properties against cancer. They are recognized as naturally occurring anti-oxidants but also act as pro-oxidants catalyzing DNA degradation in the presence of metal ions such as copper. The plant polyphenol resveratrol confers resistance to plants against fungal agents and has been implicated as a cancer chemopreventive agent. Of particular interest is the observation that resveratrol has been found to induce apoptosis in cancer cell lines but not in normal cells. Over the last few years, we have shown that resveratrol is capable of causing DNA breakage in cells such as human lymphocytes. Such cellular DNA breakage is inhibited by copper specific chelators but not by iron and zinc chelating agents. Similar results are obtained by using permeabilized cells or with isolated nuclei, indicating that chromatin-bound copper is mobilized in this reaction. It is well established that tissue, cellular and serum copper levels are considerably elevated in various malignancies. Therefore, cancer cells may be more subject to electron transfer between copper ions and resveratrol to generate reactive oxygen species responsible for DNA cleavage. The results are in support of our hypothesis that anti-cancer mechanism of plant polyphenols involves mobilization of endogenous copper and the consequent pro-oxidant action. Such a mechanism better explains the anti-cancer effects of resveratrol, as it accounts for the preferential cytotoxicity towards cancer cells.

Catalytic therapy is a cancer treatment modality based on the generation of reactive oxygen species (ROS) through administration of ascorbate/medicinal herbal extracts and copper. It is known that antioxidants such as ascorbate also exhibit prooxidant activity in the presence of transition metals such as copper. Based on our work and that in the literature, in this review we propose a mechanism for the cytotoxic action of ascorbate against cancer cells. It involves redox cycling of exogenous/endogenous copper ions and the consequent generation of ROS leading to oxidative DNA breakage. Using human peripheral lymphocytes and the Comet assay, we have shown that ascorbic acid is able to cause oxidative breakage in cellular DNA. Such DNA degradation is inhibited by neocuproine (a Cu(I) sequestering agent) and scavengers of ROS indicating that the cellular DNA breakage involves the generation of Cu(I) and formation of ROS. Similar results are also obtained with plant polyphenol antioxidants that are important constituents of medicinal herbal extracts. Copper is an essential component of chromatin and can take part in redox reactions. It is well established that tissue, cellular and serum copper levels are considerably elevated in various malignancies. Therefore, cancer cells may be more subject to electron transfer between copper ions and ascorbate/plant polyphenols to generate ROS. In this review we cite evidence to indicate that in catalytic therapy cytotoxic action against cancer cells involves redox cycling of exogenous/endogenous copper ions.

Plumbagin, a naphthoquinone derived from the medicinal plant Plumbago zeylanica has been shown to exert anticancer and anti-proliferative activities in cells in culture as well as animal tumor models. In our previous paper, we have reported the cytotoxic action of plumbagin in plasmid pBR322 DNA as well as human peripheral blood lymphocytes through a redox mechanism involving copper. Copper has been shown to be capable of mediating the action of several plant-derived compounds through production of reactive oxygen species (ROS). The objective of the present study was to determine whether plumbagin induces apoptosis in human cancer cells through the same mechanism which we proposed earlier. Using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt assay, 3-(4,5-B-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay for cell growth inhibition, histone/DNA ELISA, homogeneous caspase-3/7 assay for apoptosis as well as alkaline comet assay for DNA single-strand breaks detection in this report, we confirm that plumbagin causes effective cell growth inhibition, induces apoptosis and generates single-strand breaks in cancer cells. Incubation of cancer cells with scavengers of ROS and neocuproine inhibited the cytotoxic action of plumbagin proving that generation of ROS and Cu(I) are the critical mediators in plumbagin-induced cell growth inhibition. This study is the first to investigate the copper-mediated anticancer mechanism of plumbagin in human cancer cells and these properties of plumbagin could be further explored for the development of anticancer agents with higher therapeutic indices, especially for skin cancer.

Overexpression of Bcl-2 family proteins has been found in a variety of aggressive human carcinomas, including pancreatic cancer, suggesting that specific agents targeting Bcl-2 family proteins would be valuable for pancreatic cancer therapy. We have previously reported that TW-37, a small-molecule inhibitor of Bcl-2 family proteins, inhibited cell growth and induced apoptosis in pancreatic cancer. However, the precise role and the molecular mechanism of action of TW-37 have not been fully elucidated. In our current study, we found that TW-37 induces cell growth inhibition and S-phase cell cycle arrest, with regulation of several important cell cycle–related genes like p27, p57, E2F-1, cdc25A, CDK4, cyclin A, cyclin D1, and cyclin E. The cell growth inhibition was accompanied by increased apoptosis with concomitant attenuation of Notch-1, Jagged-1, and its downstream genes such as Hes-1 in vitro and in vivo. We also found that down-regulation of Notch-1 by small interfering RNA or γ-secretase inhibitors before TW-37 treatment resulted in enhanced cell growth inhibition and apoptosis. Our data suggest that the observed antitumor activity of TW-37 is mediated through a novel pathway involving inactivation of Notch-1 and Jagged-1. [Cancer Res 2009;69(7):2757–65]

Role of prostate apoptosis response-4 (PAR-4) has been well described in prostate cancer. However, its significance in other cancers has not been fully elucidated. For the current study, we selected four pancreatic cancer cell lines (BxPC-3, Colo-357, L3.6pl, and HPAC) that showed differential endogenous expression of PAR-4. We found that nonpeptidic small-molecule inhibitors (SMI) of Bcl-2 family proteins (apogossypolone and TW-37; 250 nmol/L and 1 μmol/L, respectively) could induce PAR-4-dependent inhibition of cell growth and induction of apoptosis. Sensitivity to apoptosis was directly related to the expression levels of PAR-4 (R = 0.92 and R2 = 0.95). Conversely, small interfering RNA against PAR-4 blocked apoptosis, confirming that PAR-4 is a key player in the apoptotic process. PAR-4 nuclear localization is considered a prerequisite for cells to undergo apoptosis, and we found that the treatment of Colo-357 and L3.6pl cells with 250 nmol/L SMI leads to nuclear localization of PAR-4 as confirmed by 4′,6-diamidino-2-phenylindole staining. In combination studies with gemcitabine, pretreatment with SMI leads to sensitization of Colo-357 cells to the growth-inhibitory and apoptotic action of a therapeutic drug, gemcitabine. In an in vivo setting, the maximum tolerated dose of TW-37 in xenograft of severe combined immunodeficient mice (40 mg/kg for three i.v. injections) led to significant tumor inhibition. Our results suggest that the observed antitumor activity of SMIs is mediated through a novel pathway involving induction of PAR-4. To our knowledge, this is the first study reporting SMI-mediated apoptosis involving PAR-4 in pancreatic cancer. [Mol Cancer Ther 2008;7(9):2884–93]

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.

It was earlier proposed that an important anti-cancer mechanism of plant polyphenols may involve mobilization of endogenous copper ions, possibly chromatin-bound copper and the consequent pro-oxidant action. This paper shows that plant polyphenols are able to mobilize nuclear copper in human lymphocytes, leading to degradation of cellular DNA. A cellular system of lymphocytes isolated from human peripheral blood and comet assay was used for this purpose. Incubation of lymphocytes with neocuproine (a cell membrane permeable copper chelator) inhibited DNA degradation in intact lymphocytes. Bathocuproine, which is unable to permeate through the cell membrane, did not cause such inhibition. This study has further shown that polyphenols are able to degrade DNA in cell nuclei and that such DNA degradation is inhibited by neocuproine as well as bathocuproine (both of which are able to permeate the nuclear pore complex), suggesting that nuclear copper is mobilized in this reaction. Pre-incubation of lymphocyte nuclei with polyphenols indicates that it is capable of traversing the nuclear membrane. This study has also shown that polyphenols generate oxidative stress in lymphocyte nuclei which is inhibited by scavengers of reactive oxygen species (ROS) and neocuproine. These results indicate that the generation of ROS occurs through mobilization of nuclear copper resulting in oxidatively generated DNA breakage.

Plant-derived dietary material contains several classes of polyphenols such as flavonoids, curcuminoids, stilbenes and hydroxycinnamic acids. They are recognized as naturally occurring antioxidants but also act as prooxidants catalyzing cellular DNA degradation in the presence of transition metal ions such as copper. Earlier we have shown that the stilbene resveratrol is able to mobilize endogenous copper ions leading to oxidative breakage of cellular DNA. In this paper, we show that caffeic acid (a hydroxycinnamic acid), which is a major constituent of coffee, is also capable of DNA breakage in human peripheral lymphocytes. Incubation of lymphocytes with neocuproine inhibited the DNA degradation confirming that Cu(I) is an intermediate in the DNA cleavage reaction. Further, we have also shown that caffeic acid generates oxidative stress in lymphocytes, which is inhibited by scavengers of reactive oxygen species and neocuproine. These results are in further support of our hypothesis that anticancer mechanism of plant polyphenols involves mobilization of endogenous copper, possibly chromatin bound copper, and the consequent prooxidant action.

Cancer arises in the context of an in vivo tumor microenvironment. This microenvironment is both a cause and consequence of tumorigenesis. Tumor and host cells co-evolve dynamically through indirect and direct cellular interactions, eliciting multiscale effects on many biological programs, including cellular proliferation, growth, and metabolism, as well as angiogenesis and hypoxia and innate and adaptive immunity. Here we highlight specific biological processes that could be exploited as targets for the prevention and therapy of cancer. Specifically, we describe how inhibition of targets such as cholesterol synthesis and metabolites, reactive oxygen species and hypoxia, macrophage activation and conversion, indoleamine 2,3-dioxygenase regulation of dendritic cells, vascular endothelial growth factor regulation of angiogenesis, fibrosis inhibition, endoglin, and Janus kinase signaling emerge as examples of important potential nexuses in the regulation of tumorigenesis and the tumor microenvironment that can be targeted. We have also identified therapeutic agents as approaches, in particular natural products such as berberine, resveratrol, onionin A, epigallocatechin gallate, genistein, curcumin, naringenin, desoxyrhapontigenin, piperine, and zerumbone, that may warrant further investigation to target the tumor microenvironment for the treatment and/or prevention of cancer.

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.

Here we demonstrate for the first time that targeted inhibition of nuclear exporter protein exportin 1 (XPO1) also known as chromosome maintenance region 1 (CRM1) by Selective Inhibitor of Nuclear Export (SINE) compounds results in reversal of EMT in snail-transduced primary human mammary epithelial cells (HMECs). SINE compounds selinexor (KPT-330) and KPT-185, leptomycin B (LMB as +ve control) but not KPT-301 (–ve control) reverse EMT, suppress mesenchymal markers and consequently induce growth inhibition, apoptosis and prevent spheroid formation. SINE treatment resulted in nuclear retention of snail regulator FBXL5 that was concurrent with suppression of snail and down-regulation of mesenchymal markers. FBXL5 siRNA or transfection with cys528 mut-Xpo1 (lacking SINE binding site) markedly abrogated SINE activity highlighting an XPO1 and FBXL5 mediated mechanism of action. Silencing XPO1 or snail caused re-expression of FBXL5 as well as EMT reversal. Pathway analysis on SINE treated HMECs further verified the involvement of additional F-Box family proteins and confirmed the suppression of snail network. Oral administration of selinexor (15 mg/kg p.o. QoDx3/week for 3weeks) resulted in complete cures (no tumor rebound at 120 days) of HMLER-Snail xenografts. These findings raise the unique possibility of blocking EMT at the nuclear pore.

Over the years, several lines of evidence have emerged supporting the role of stress in the development and progression of cancer. Stress can cause an increase in the production of reactive oxygen species (ROS) and decrease in the in vivo antioxidant defense systems. A ROS-induced DNA damage in peripheral lymphocytes, liver and skin cells may be revealed by Comet assay. To test whether DNA is damaged by stress/DMBA/stress and DMBA, rats were exposed to multiple doses of DMBA in the presence and absence of restraint stress, and DNA damage was evaluated. Insignificant differences were detected in all the three cells tested (peripheral lymphocytes, liver and skin cells) between control and stress treatment in terms of frequencies of damaged DNA. The extent of DNA migration was enhanced in DMBA treated rats in a dose dependent manner. Pre-stress DMBA treatment showed still higher frequencies of damage in comparison with control, stress alone or DMBA alone groups. Thus, prior exposure to stress clearly enhanced the DMBA induced DNA damage, especially so in the skin cells (target organ of the carcinogen application) than liver and peripheral lymphocytes as observed on the basis of the extent of DNA migration (tail DNA) during single cell gel electrophoresis.

Non-coding RNAs (ncRNAs) are broadly classified as house-keeping and regulatory ncRNAs. The house keeping ncRNAs include the ribosomal RNA, transfer RNA, small nuclear RNA and snoRNA. While the regulatory ncRNA classification is based on length and include shorter microRNAs, snRNAs, piRNAs or the long ncRNAs (lncRNAs) that are greater than 200 nucleotides (nt) (1).

The evasion of anti-growth signaling is an important characteristic of cancer cells. In order to continue to proliferate, cancer cells must somehow uncouple themselves from the many signals that exist to slow down cell growth. Here, we define the anti-growth signaling process, and review several important pathways involved in growth signaling: p53, phosphatase and tensin homolog (PTEN), retinoblastoma protein (Rb), Hippo, growth differentiation factor 15 (GDF15), AT-rich interactive domain 1A (ARID1A), Notch, insulin-like growth factor (IGF), and Krüppel-like factor 5 (KLF5) pathways. Aberrations in these processes in cancer cells involve mutations and thus the suppression of genes that prevent growth, as well as mutation and activation of genes involved in driving cell growth. Using these pathways as examples, we prioritize molecular targets that might be leveraged to promote anti-growth signaling in cancer cells. Interestingly, naturally occurring phytochemicals found in human diets (either singly or as mixtures) may promote anti-growth signaling, and do so without the potentially adverse effects associated with synthetic chemicals. We review examples of naturally occurring phytochemicals that may be applied to prevent cancer by antagonizing growth signaling, and propose one phytochemical for each pathway. These are: epigallocatechin-3-gallate (EGCG) for the Rb pathway, luteolin for p53, curcumin for PTEN, porphyrins for Hippo, genistein for GDF15, resveratrol for ARID1A, withaferin A for Notch and diguelin for the IGF1-receptor pathway. The coordination of anti-growth signaling and natural compound studies will provide insight into the future application of these compounds in the clinical setting.

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.

Objective: The p21-activated kinase 4 (PAK4) is a key downstream effector of the Rho GTPase family and is over-expressed in many different cancer types. PAK4 protein, by virtue of its ability to engage multiple ligands, regulates a repertoire of signaling pathways. A survey of non-Hodgkin’s lymphoma (NHL) cell lines shows that there is increase in PAK4 mRNA and/or protein expression when compared to normal peripheral lymphocytes (PBL). Considering PAK4 RNA interference suppresses lymphoma cell proliferation, these findings point to a novel role for PAK4 in promoting NHL cell growth. To this end we examined the impact of the newly developed PAK4 allosteric modulators (PAMs) on NHL proliferation both in vitro and in vivo. Methods: WSU-FSCCL (representing follicular small cell cleaved lymphoma) and WSU-DLCL2 (diffused large B-cell lymphoma) were exposed to increasing concentrations of different PAM analogs (KPT-7523, KPT-7189, KPT-9037, KPT-9274, or KPT-7010 [inactive]) or the Pan-PAK inhibitor, PF-3758309, in the presence or absence of CHOP (used at IC25) for 72 hrs. Following combination treatment viability was evaluated using Trypan Blue, apoptosis was analyzed using 7AAD, tetrachrome staining, Annexin V FITC and cell cycle arrest was accessed by flow cytometry. Protein and mRNA expression changes were evaluated using immunoblotting and RT-PCR. The toxicity and efficacy of PAMs were evaluated in sub-cutaneous and disseminated xenograft models of NHL. Results: As single agents, PAMs show anti-proliferative activity in vitro against NHL cell lines (IC50s for: WSU-FSCCL = 50 nM and WSU-DLCL2 = 250 nM) while sparing normal PBL (IC50s in μM range). There was a statistically significant dose-dependent difference in apoptosis induction in NHL cell lines treated with PAMs when compared to vehicle control. PAMs reduced total p-PAK4 and downstream signaling proteins involved in proliferation and apoptosis. In R-CHOP combination studies we observed enhanced viability suppression, increased apoptosis, and concurrent down-regulation of PAK4 signaling pathway proteins when compared to any single agent alone. The clinical compound, KPT-9274, is well tolerated and showed remarkable anti-tumor activity in WSU-DLCL2 sub-cutaneous xenograft in mice (p < 0.01 at 140 mg/kg/bid for 4 weeks with no loss in body weight). Residual tumors analysis showed suppression of PAK4 signaling pathways. Single agent and R-CHOP combination efficacy is currently being evaluated in subcutaneous and systemic WSU-FSCCL and in primary patient derived xenografts in mice. Conclusions: This is the first study demonstrating a role for PAK4 in diffused large B-cell and follicular small cell cleaved NHL. Our data shows that inhibition of PAK4 could become a viable therapy for NHL either alone or in combination with R-CHOP. Our data is directly applicable to the current Phase 1 trial of KPT-9274 in patients with advanced solid malignancies or NHL. Citation Format: Asfar S. Azmi, Amro Aboukameel, Irfana Muqbil, Yiwei Li, William Senapedis, Erkan Baloglu, Yosef Landesman, Michael Kauffman, Sharon Shacham, Ayad Al-Katib, Ramzi M. Mohammad. p21 activated kinase 4 (pak4) as a novel therapeutic target for non-hodgkin's lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1358. doi:10.1158/1538-7445.AM2017-1358

Objective: There are no known reports on the role of exportin 1 (XPO1; also known as chromosome maintenance region 1 [CRM1]) in microRNA biology. In this study, we for the first time demonstrate that interfering with XPO1 machinery can influence miRNA signaling leading to suppression of pancreatic ductal adenocarcinoma (PDAC) proliferation, invasion and metastasis. Methods: miRNA arrays (LCSciences, Houston, TX) were performed on total RNA samples from PDAC cell lines (HPAC, MiaPaCa-2, AsPc-1 and L3.6pl) and normal human pancreatic ductal epithelial (HPDE) cells. PDAC cells were treated with XPO1 inhibitor (Selinexor) or transfected with control siRNA, XPO1 siRNA (Santa Cruz), miR-control or miR-145 mimic (Applied biosystems) all at a final concentration of 20 nM using DharmaFact Transfection Reagent (Dharmacon, Lafayette. CO). The total RNA and total protein from treated or transfected cells were subjected to real-time PCR or immunoblot analysis in order to measure expression level of miR-145, let-7d, miR-34c, miR-320, miR-205, and miR-145 target or downstream genes including EGFR, MMP1, MT-MMP, c-Myc, Sox-2, and PAK4. The impact of XPO1 inhibitor Selinexor on PDAC growth, proliferation, invasion and migrations was also evaluated using MTT and scratch assay. Results: In this study, we show that PDAC cells have significantly reduced expression of miR-145 when compared to normal pancreatic duct epithelial cells. Similarly, forced expression of miR-145 in PDAC cells inhibited cell proliferation and migration. Conversely, we demonstrate that RNAi of XPO1 by siRNA knockdown or chemical inhibition of XPO1 by selective inhibitor of nuclear export compound (Selinexor) restores miR-145 expression in PDAC cells ultimately leading to inhibition of cell proliferation and migration. In addition, we show that the inhibition of cell proliferation and migration by Selinexor is mediated through the down-regulation of known miR-145 signals including EGFR, MMP1, MT-MMP, c-Myc, PAK4 and Sox-2. Selinexor also induced the expression of two important tumor suppressive miRNAs, miR-34c and let-7d, leading to the up-regulation of p21WAF1. We also observed the down-regulation of oncomir mir-205. Conclusions: These results are the first to show that targeted inhibition of the nuclear exporter protein XPO1 by RNAi or Selinexor could restore tumor suppressive miRs in PDAC. Citation Format: Asfar S. Azmi, Yiwei Li, Irfana Muqbil, Amro Aboukameel, William Senapedis, Erkan Baloglu, Yosef Landesman, Michael Kauffman, Sharon Shacham, Philip A. Philip, Ramzi M. Mohammad. Novel role of xpo1 in regulating MicroRNAs related to pancreatic ductal adenocarcinoma invasion and metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 464. doi:10.1158/1538-7445.AM2017-464

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.

Epithelial-to-mesenchymal transition (EMT) and the reverse process (MET) plays central role in organ developmental biology. It is a fine tuned process that when disturbed leads to pathological conditions especially cancers with aggressive and metastatic behavior. Snail is an oncogene that has been well established to be a promoter of EMT through direct repression of epithelial morphology promoter E-cadherin. It can function in the nucleus, in the cytosol and as discovered recently, extracellularly through secretory vesicular structures. The intracellular transport of snail has for long been shown to be regulated by the nuclear pore complex. One of the Karyopherins, importin alpha, mediates snail import, while importin beta/exportin 1 (Xpo1) or chromosome maintenance region 1 (CRM1) is its major nuclear exporter. A number of additional biological regulators are emerging that directly modulate Snail stability by altering its subcellular localization. These observations indicate that targeting the nuclear transport machinery could be an important and as of yet, unexplored avenue for therapeutic intervention against the EMT processes in cancer. In parallel, a number of novel agents that disrupt nuclear transport have recently been discovered and are being explored for their anti-cancer effects in the early clinical settings. Through this review we provide insights on the mechanisms regulating snail subcellular localization and how this impacts EMT. We discuss strategies on how the nuclear transport function can be harnessed to rein in EMT through modulation of snail signaling.

Subpopulations of cancer stem cells (CSCs) or cancer stem-like cells (CSLCs) have been identified from most tumors, including pancreatic cancer (PC), and the existence of these cells is clinically relevant. Emerging evidence suggests that CSLCs participate in cell growth/proliferation, migration/invasion, metastasis, and chemo-radiotherapy resistance, ultimately contributing to poor clinical outcome. However, the pathogenesis and biological significance of CSLCs in PC has not been well characterized. In the present study, we found that isolated triple-marker-positive (CD44(+)/CD133(+)/EpCAM(+)) cells of human PC MiaPaCa-2 and L3.6pl cells behave as CSLCs. These CSLCs exhibit aggressive behavior, such as increased cell growth, migration, clonogenicity, and self-renewal capacity. The mRNA expression profiling analysis showed that CSLCs (CD44(+)/CD133(+)/EpCAM(+)) exhibit differential expression of more than 1,600 mRNAs, including FoxQ1, compared with the triple-marker-negative (CD44(-)/CD133(-)/EpCAM(-)) cells. The knockdown of FoxQ1 by its siRNA in CSLCs resulted in the inhibition of aggressive behavior, consistent with the inhibition of EpCAM and Snail expression. Mouse xenograft tumor studies showed that CSLCs have a 100-fold higher potential for tumor formation and rapid tumor growth, consistent with overexpression of CSC-associated markers/mediators, including FoxQ1, compared with its parental MiaPaCa-2 cells. The inhibition of FoxQ1 attenuated tumor formation and growth, and expression of CSC markers in the xenograft tumor derived from CSLCs of MiaPaCa-2 cells. These data clearly suggest the role of differentially expressed genes in the regulation of CSLC characteristics, further suggesting that targeting some of these genes could be important for the development of novel therapies for achieving better treatment outcome of PC.

In spite of the expensive preclinical testing, the consistent failure to translate many promising targeted drugs from the laboratory bench to the clinic raises the question of whether the single-pathway drug-discovery strategies offer the correct perspective. As revealed by network biology, cancers harbor robust biological networks that are inherently resistant to changes, such as those induced by drugs with very narrow mechanisms of action. Therefore, network pharmacology strategies, the treatment of cancer by modulating more than one target, are needed. Different promiscuous approaches targeting multiple avenues within cancer-associated networks, such as the pleiotropic natural products, are emerging. Nevertheless, there is a long way before such ‘proof-of-concept strategies’ can be successfully applied in the clinical setting. This article provides a perspective on the current challenges in drug discovery, the reasons for high failure rates and how network pharmacology can aid the successful design of agents against cancer.

Advanced pancreatic adenocarcinoma is a deadly disease and is considered incurable. For the past two decades, gemcitabine remained the major chemotherapeutic drug with modest clinical benefit. Many chemotherapy and targeted agents were combined with gemcitabine but failed to demonstrate improvement in pancreatic cancer (PC) survival. Taxanes (paclitaxel, docetaxel) were introduced in the clinic as anti-microtubule agents and showed activity against PC cells in vitro; however, clinical efficacy was limited. Nab-paclitaxel (Abraxane) is an albumin-bound paclitaxel that has shown clinical activity in advanced breast and lung cancer. Recently, nab-paclitaxel was tested in a large Phase III clinical trial in combination with gemcitabine for the treatment of advanced PC. The data showed that the addition of nab-paclitaxel improved the response rate (7% in gemcitabine alone versus 23% in combination), progression-free survival (from 3.7 months to 5.5 months), and overall survival from 6.7 months to 8.5 months, compared to single agent gemcitabine. Through this review, we provide the preclinical and clinical progress in the development of nab-paclitaxel for the treatment of metastatic PC.

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.

Reactive oxygen species (ROS) have been widely considered as critical cellular signaling molecules involving in various biological processes such as cell growth, differentiation, proliferation, apoptosis, and angiogenesis. The homeostasis of ROS is critical to maintain normal biological processes. Increased production of ROS, namely oxidative stress, due to either endogenous or exogenous sources causes irreversible damage of bio-molecules such as DNA, proteins, lipids, and sugars, leading to genomic instability, genetic mutation, and altered gene expression, eventually contributing to tumorigenesis. A great amount of experimental studies in vitro and in vivo have produced solid evidence supporting that oxidative stress is strongly associated with increased tumor cell growth, treatment resistance, and metastasis, and all of which contribute to tumor aggressiveness. More recently, the data have indicated that altered production of ROS is also associated with cancer stem cells (CSCs), epithelial-to-mesenchymal transition (EMT), and hypoxia, the most common features or phenomena in tumorigenesis and tumor progression. However, the exact mechanism by which ROS is involved in the regulation of CSC and EMT characteristics as well as hypoxia- and, especially, HIF-mediated pathways is not well known. Emerging evidence suggests the role of miRNAs in tumorigenesis and progression of human tumors. Recently, the data have indicated that altered productions of ROS are associated with deregulated expression of miRNAs, suggesting their potential roles in the regulation of ROS production. Therefore, targeting ROS mediated through the deregulation of miRNAs by novel approaches or by naturally occurring anti-oxidant agents such as genistein could provide a new therapeutic approach for the prevention and/or treatment of human malignancies. In this article, we will discuss the potential role of miRNAs in the regulation of ROS production during tumorigenesis. Finally, we will discuss the role of genistein, as a potent anti-tumor agent in the regulation of ROS production during tumorigenesis and tumor development.

Pancreatic cancer (PC) is a deadly disease that is not amenable to any of the currently available treatment modalities. PC harbors a complex signaling that has both genetic and epigenetic origin. MicroRNAs (miRNAs) are short noncoding RNAs that are recognized to epigenetically modulate gene expression by weakly binding to the 3′ translated region of target mRNAs. A number of microRNAs have been recognized to be expressed aberrantly in PC. These findings have led researchers to aggressively pursue miRNAs for diagnostic and therapeutic markers in PC. Both identification and targeting of miRNAs is not straightforward, however, because each miRNA can modulate hundreds of different genes which in turn can influence an exponential number of different targets. In recent years, there has been a consensus that the complexity of miRNAs requires holistic approaches involving systems and computational components to tease out the specific target of each miRNA, which appear to be context dependent. This chapter comprehensively evaluates the importance of miRNAs in PC and how computational biology, particularly systems and network biology, can help prioritize miRNAs for diagnostic and therapeutic benefits.

Pancreatic ductal adenocarcinoma (PDAC) harbors a very complex biological signaling network that is highly resistant or in systems terms “robust”. Such biological robustness cannot be perturbed by very specific drugs and this is reflected in the failure of most of the currently available single pathway therapeutic strategies in PDAC. To date the network targeted chemotherapeutics (gemcitabine, oxaliplatin, their combination FULFIRINOX) and promiscuous agents such as nab-paclitaxel remain the backbone of the partially successful therapies against PDAC. This shows that in order to impact PDAC robustness, network targeted agents that hit multiple avenues to induce biologically meaningful impact are needed. Network pharmacology is an emerging technology that takes information from complex biological networks of gene/proteins or molecular interactions to decide what network nodes or edges are potential targets for therapeutic intervention. If applied correctly, network pharmacology can help in understanding PDAC signaling and also aid in the design of resistance reverting polypharmacology strategies. This chapter provides the background knowledge on network pharmacology and highlights the available Web resources that can be used in the successful design of pharmacology strategies against deadly PDAC.

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.

The concept of cancer stem cells (CSCs) has great clinical implications because small sub-populations of CSCs have been identified in many different tumors that are associated with poor clinical outcome. Sufficient evidence supports central functions of CSCs in tumorigenesis, due to its distinct high potentials of self-renewal, pluripotent differentiation and apoptosis-resistance, contributing to tumor aggressiveness. Therefore, inhibiting/eliminating CSCs will provide a new effective therapeutic approach for the treatment of aggressive tumors. However, the mechanistic roles of CSCs in tumorigenesis are not well understood. MicroRNAs (miRNAs) have been discovered to act as key regulators of gene expression in tumorigenesis. Aberrant expression of miRNAs has been discovered to be related to worse clinical outcome of many different tumors. Evidence shows that these tumor-related miRNAs have key functions in the regulation of cell cycle/proliferation, migration/invasion, chemo-radiation resistance, and metastasis. Moreover, miRNAs may also exert important functions in modulating CSC characteristics; however, its detailed mechanism(s) has not been fully elucidated. Here, we will summarize the potential role of CSC-related miRNAs in CSC function, and will further define the role of genistein in targeting these CSC-related miRNAs.

Trafficking of biological materials across nuclear membrane is an evolutionarily conserved mechanism that maintains normal eukaryotic cell homeostasis. Eukaryotes shuttle proteins and RNAs in and out of the cell nucleus using highly complex gated machinery. Smaller entities can enter and exit the nuclear pore through diffusion. The movement of most of the proteins and RNAs, however, requires active transport that is mediated by specialized carriers in a strictly controlled manner. Such energy dependent trafficking occurs through the nuclear pore complex (NPC) that is embedded in the nuclear membrane. The last two decades have witnessed tremendous advancements in the understanding of the NPC. Such studies have helped in the characterization of major nuclear transport mediators belonging to the Karyopherin family proteins that maintain proper compartmentalization of micro- and macro-molecules. This is functionally critical for tumor suppressor proteins (TSPs) and transcription factors (TFs) that require nuclear retention and sequence specific DNA alignment to modulate their target gene expression or conduct genome surveillance activity. Indeed, cancer cells have evolved methods to disturb the nuclear traffic by abnormal expression of the nuclear exporters particularly exportin 1 (Xpo1) that leads to a cascade of de-regulations favoring uncontrolled growth and loss of surveillance within the cells. Major cancer hallmarks have been shown to be influenced by Xpo1 de-regulation directly or indirectly. Recently, specific inhibitors of nuclear export (SINE) have been developed as a broad form of therapy targeting global re-alignment of multiple TSPs in the correct cellular compartment through inhibition of Xpo1 to rein in cancer. SINEs are currently undergoing Phase I and Phase Ib/II clinical evaluation. The drugs show single agent efficacy both in solid tumors and hematological malignancies.

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.

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.

“Let food be thy medicine and medicine be thy food” was quoted by Hippocrates more than two thousand years ago and since ancient times the health benefits of different natural agents have been exploited. In modern research, the disease preventive benefits of many such natural agents, particularly dietary compounds and their derivatives, has been attributed to their well recognized activity as the regulators of redox state of the cell. Nevertheless, most of these studies have focused on their antioxidant activity. A large body of evidence indicates that a major fraction of these agents can elicit pro-oxidant (radical generating) behavior which has been linked to their anti-cancer effects. This editorial provides an overview of the under-appreciated pro-oxidant activity of natural products, with a special focus on their ability to generate reactive oxygen species in the presence of transition metal ions, and discusses their possible use as cancer chemotherapeutic agents.

The identification of small subpopulations of cancer stem cells (CSCs) from blood mononuclear cells in human acute myeloid leukemia (AML) in 1997 was a landmark observation that recognized the potential role of CSCs in tumor aggressiveness. Two critical properties contribute to the functional role of CSCs in the establishment and recurrence of cancerous tumors: their capacity for self-renewal and their potential to differentiate into unlimited heterogeneous populations of cancer cells. These findings suggest that CSCs may represent novel therapeutic targets for the treatment and/or prevention of tumor progression, since they appear to be involved in cell migration, invasion, metastasis, and treatment resistance-all of which lead to poor clinical outcomes. The identification of CSC-specific markers, the isolation and characterization of CSCs from malignant tissues, and targeting strategies for the destruction of CSCs provide a novel opportunity for cancer research. This overview describes the potential implications of several common CSC markers in the identification of CSC subpopulations that are restricted to common malignant diseases, e.g., leukemia, and breast, prostate, pancreatic, and lung cancers. The role of microRNAs (miRNAs) in the regulation of CSC function is also discussed, as are several methods commonly used in CSC research. The potential role of the antidiabetic drug metformin- which has been shown to have effects on CSCs, and is known to function as an antitumor agent-is discussed as an example of this new class of chemotherapeutics.

Pancreatic cancer [PC] is a complex disease harboring multiple genetic alterations. It is now well known that deregulation in the expression and function of oncogenes and tumor suppressor genes contributes to the development and progression of PC. The last 40 years have not seen any major improvements in the dismal overall cure rate for PC where drug resistance is an emerging and recurring obstacle for successful treatment of PC. Additionally, the lack of molecular biomarkers for patient selection limits drug availabilities for tailored therapy for patients diagnosed with PC. The very high failure rate of new drugs in Phase III clinical trials in PC calls for a more robust pre-clinical and clinical testing of new compounds. In order to rationally choose combinations of targeted agents that may improve therapeutic outcome by overcoming drug resistance, one needs to apply newer research tools such as systems and network biology. These newer tools are expected to assist in the design of effective drug combinations for the treatment of PC and are expected to become an important part in any future clinical trials. In this review we will provide background information on the current state of PC research, the reasons for drug failure and how to overcome these issues using systems sciences. We conclude this review with an example on how systems and network methodologies can help in the design efficacious drug combinations for this deadly and by far incurable disease.

Extensive researches within the last decade have revealed the presence of a complex network of signaling pathways overtly active in cancer cells augmenting proliferation and suppressing apoptosis. In parallel, epidemiological literature summarized a casual association between consumption of well balanced diet comprising adequate fruits and vegetables with reduced risk of developing cancer. This was projected to be associated with the presence of well characterized bioactive compounds, e.g. flavonoids, isothiocyanates, catechins, phenolic acid and organic sulphur present in diet that lead to the development of preventive and therapeutic strategies. Emerging evidence narrate mechanistic insight relating to the pleiotropic role of these bioactive compounds in modulating proliferation linked signaling at multiple levels including Akt, nuclear transcription factor-κB, c-Myc, cycloxygenase-2, MAPK, STAT and other signaling pathways that are active during embryogenesis, such as hedgehog and Wnt signalings. Preclinical studies including genetically modified mouse models revealed that dietary bioactive compounds hitherto classed as ‘chemopreventive agents’ induce apoptosis in cancer cells and inhibit development and/or progression of tumor. This chapter presents a comprehensive overview of deregulated signaling mechanisms prevailing within tumor cells along with broad knowledge-based evidence intertwining biological and molecular basis of action of chemopreventive agents citing representative examples. Additionally, an important aspect relating to the noteworthy rationale of using bioactive chemopreventive agents for sensitizing tumors to improve efficacy of chemotherapy in clinics has been discussed briefly. Finally, to bring forward the potential of natural chemopreventive agents to full extent, the development of safe and tolerable pharmaceutical grade analogs with improved bioavailability is encouraged to reduce the incidence and mortality of cancer.

The cancer stem cell (CSC) hypothesis is increasingly being accepted as a model to explain for the functional heterogeneity that is commonly observed in solid tumors. According to this hypothesis, there exists a hierarchical organization of cells within the tumor, in which a differential subpopulation of stem-like cells is responsible for sustaining and recurrence of tumor growth. CSCs have been shown to exist in a variety of solid tumors especially those with known resistant phenotypes such as breast, prostate and pancreatic adenocarcinoma (PDAC). In all these models, the commonality of deregulation of three crucial pathways; Wnt, notch and hedgehog that maintain CSC self-renewal capacity is emerging. Collectively these major pathways and have been linked to the observed resistance of CSC to chemotherapy and radiotherapy. The existing lack of knowledge and our incomplete understanding of the molecular signatures associated with CSCs highlight the need for better approaches in both isolation and identification of unique pathways associated with these cells. In this direction, computational biology, especially systems and network approaches, have proven to be of great utility in unraveling pathway complexities such as those associated with CSCs. With highlights on the most up-to-date molecular, network, cellular, clinical, and therapeutic cancer research findings, this article tends to provide a wealth of insights on systems and network biology approaches to CSC marker identification, the mechanism through which they evade treatment as well as therapeutic approaches that will help in conquering these elusive cells in incurable and refractory malignancies.

Pancreatic cancer (PC) is highly resistant to conventional therapeutics, and it is a complex disease which is partly characterized by genetic and epigenetic de-regulation of many signaling pathways. Among the numerous de-regulated mechanisms aberrant expression of small non-coding MicroRNAs (miRNAs) are very important. Intense research in this area has lead to the identification and characterization of critically de-regulated miRNAs which raises our hope that targeting them may lead to clinically beneficial outcome of patients diagnosed with PC. Emerging evidence suggests that miRNAs are under a highly coordinated epigenetic regulation, which could be exploited for the development of novel therapeutics. For the success of miRNA based therapeutic regimens, a holistic approach may be required that takes into account the emerging epigenetic regulatory mechanisms. In this chapter, the aberrant epigenetic grooming of miRNAs especially in PC and computational strategies especially systems and network biology to target them are discussed.

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.