bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2742: Activation of Wnt/β-catenin signaling accelerates progression of Kras-induced pancreatic cancer.
Authors: Sano Makoto , Driscoll David R. , DeJesus-Monge Wilfredo E. , Klimstra David S. , Lewis Brian C.
Published: August 2014

Pancreatic ductal adenocarcinoma (PDAC), a poor prognostic cancer, commonly develops following activating mutations in the KRAS oncogene. Activation of the Wnt signaling pathway is also commonly observed in PDAC. To ascertain the impact of postnatal activation of the Wnt signaling pathways in PDAC development, we combined the elastase-tva-based RCAS-TVA pancreatic cancer model with the established LSL-KrasG12D, Ptf1a-cre model. Delivery of RCAS viruses encoding β-cateninS37A and Wnt1 stimulated the progression of premalignant PanIN and PDAC development. Moreover, mice injected with RCAS-β-cateninS37A and Wnt1 had reduced survival relative to RCAS-GFP controls (log-rank test; p < 0.05). Meanwhile, active β-catenin or its DNA-binding partner TCF4 enhanced PDAC cell proliferation, soft-agar colony formation, as well as migration and invasion activity. In contrast, these phenotypes were significantly blocked by the introduction of Icat, an inhibitor of the β-catenin/TCF4 interaction. Interestingly, Id2 (inhibitor of differentiation/DNA binding2) was significantly up-regulated by induction of β-catenin and TCF4, whereas Id2 expression was inhibited by Icat. Furthermore, nuclear β-catenin and Id2 were mainly observed in poorly differentiated PDACs and sarcomatoid tumors. Together, these data suggest that the Wnt/β-catenin signaling pathway stimulates pancreatic tumor development and progression through the activation of Id2.

Citation Format: Makoto Sano, David R. Driscoll, Wilfredo E. DeJesus-Monge, David S. Klimstra, Brian C. Lewis. Activation of Wnt/β-catenin signaling accelerates progression of Kras-induced pancreatic cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2742. doi:10.1158/1538-7445.AM2013-2742
Abstract 275: Development of RNAi-dendrimer-based Twist1 inhibitors to reduce metastasis and recurrence in ovarian cancer.
Authors: Roberts Cai , Finlay James , Lowe Gina , Dellinger Thanh H. , Han Ernest , Glackin Carlotta
Published: August 2014

Background/Objective: Epithelial ovarian cancer (EOC) is the most lethal gynecologic cancer, with the vast majority of patients eventually developing a recurrence. One promising novel therapeutic target is Twist1, a basic helix-loop-helix transcription factor that acts as a master regulator of epithelial to mesenchymal transition (EMT), an important step in metastasis, of which loss of E-cadherin is the hallmark. Furthermore, Twist1 is a key component in the differentiation of EOC stem cells into metastatic cancer cells.

Methods: We investigated the effectiveness of three siTwist-candidates and two types of Poly (amidoamine) (PAMAM) dendrimers on intracellular delivery of siRNA to ovarian cancer cell lines. The EOC cell lines TOV112D, TARA R182 (immortalized primary EOC cells) and A2780R (cisplatin-resistant derivatives of the A2780 EOC cell line) were used. Two types of PAMAM dendrimers, Generation 5 (G5) and a new G3 dendrimer (YTZ3-15) were examined, which differ based on the numbers of surface amines. We complexed multiple Twist1-specific siRNA constructs to PAMAM dendrimers to protect fragile RNA and facilitate delivery. We loaded G5 and YTZ3-15 dendrimers with Cy3-labeled siTwist-506 and transfected TOV112D cells with these complexes. Quantitative real-time PCR (QPCR) and Western blotting were used to evaluate Twist1 knockdown in four EOC cell lines following transfection with siTwist.

Results: Bright field and fluorescent microscopy analysis showed that ∼95-98% of TOV112D cells contained Cy3 label, indicating that both the G5 and YTZ3-15 dendrimers can penetrate the cell membranes of EOC cells. Cy3-labeled siTwist-506 led to a 50% reduction in Twist1 mRNA in these cells. Further analysis revealed that novel siRNA sequences siTwist-419 and 494 significantly reduced Twist1 protein expression compared to siTw506 and non-transfected controls, and real-time RT-PCR analysis revealed a 80% reduction in Twist1 mRNA in both TARA R182 and A2780R EOC cells. This suggests that siTwist-419 and 494 can lead to optimal Twist1 silencing.

Conclusions: Our data support the feasibility of using siTwist-dendriplex approaches to knock down Twist1 expression in EOC cells, by circumventing a major obstacle to the targeting of transcription factors with dendrimer technology. Further studies are needed to prove whether the prevention of Twist1 production will reduce EOC metastases, and prevent recurrences by arresting EOC stem cells in an undifferentiated state.

Citation Format: Cai Roberts, James Finlay, Gina Lowe, Thanh H. Dellinger, Ernest Han, Carlotta Glackin. Development of RNAi-dendrimer-based Twist1 inhibitors to reduce metastasis and recurrence in ovarian cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 275. doi:10.1158/1538-7445.AM2013-275
Abstract 282: Vimentin serves as a signaling scaffold at focal adhesion sites to regulate lung cancer cell adhesion.
Authors: Havel Lauren , Marcus Adam I.
Published: August 2014

Vimentin is a dynamic type III intermediate filament that is overexpressed in various cancers including non-small cell lung cancer (NSCLC). It is a classic biomarker for highly invasive tumors and is associated with increased likelihood of metastasis and poor survival. Vimentin filaments are dynamic and localize to focal adhesions, where they assemble and disassemble to promote cell migration. Our data show that vimentin depletion reduces cell adhesion and phosphorylated focal adhesion kinase (pFAK); therefore, we hypothesize that vimentin acts through FAK to regulate cell adhesion and metastasis. We show that vimentin filaments enter pFAK- and pSrc-positive focal adhesion sites, and upon vimentin depletion, pFAK, pSrc and total FAK levels decrease. To explore the mechanism behind this observation, we performed a phospho-proteomic screen for proteins whose phosphorylation is altered upon vimentin loss. One of the identified proteins was a guanine nucleotide exchange factor (GEF) that regulates rac1. We show that vimentin loss leads to GEF mis-localization and downstream rac1 inactivation. Furthermore, inactivation of the GEF itself resulted in aberrant cellular adhesion and loss of pFAK. Based upon this data, we propose that vimentin serves as a signaling scaffold to regulate FAK via a rac1-GEF interaction. This work provides insight into the mechanism by which vimentin affects cell adhesion and potentially NSCLC metastasis.

Citation Format: Lauren Havel, Adam I. Marcus. Vimentin serves as a signaling scaffold at focal adhesion sites to regulate lung cancer cell adhesion. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 282. doi:10.1158/1538-7445.AM2013-282
Abstract 2820: The mechanism of mesenchymal-to-epithelial transition driven by hepatocytes in prostate cancer.
Authors: Ma Bo , Wells Alan
Published: August 2014

Metastasis of prostate cancer (PCa) almost always leads inexorably to death, but little is known about how cancer cells seed ectopic sites and survive in these inhospitable sites. Our lab has previously shown that carcinoma cells undergo a phenotypic change driven by the metastatic microenvironment, to attain an, at least partial mesenchymal (like)-to-epithelial reverting transition (MET/MErT). This phenotypic plasticity, marked by E-cadherin re-expression, plays a key role in metastatic breast and prostate cancer cell survival in vitro and is though to occur after seeding in the ectopic sites and subsequent treatment with chemotherapeutics. In this study we are seeking the pathway(s) involved in the mesenchymal to epithelial transition and subsequent cell survival. By using hepatocytes co-cultured with prostate cancer cells (DU145 or PC3) we found MET PCa cells displayed more resistance to chemotherapeutics, cell death inducing cytokines, or a combination of both. Moreover, E-cadherin knockdown in PCa cells abolished this survival advantage conferred by hepatocytes. This indicated the key role of E-cadherin in hepatocyted driven PCa cells survival. We focused next on the feedback pathways activated by E-cadherin homotypic binding, the MAP kinases. Our data showed that p38 MAPK regulated E-cadherin expression during DU145 cells MET driven by hepatocytes. By using immunofluorescence, the level of phosphor-p38 was much lower in DU145 cells co-cultured with hepatocytes, and the p38 was only detected in the nucleus, which suggested that hepatocytes suppressed p38 MAPK activity in DU145 cells. When co-cultured with hepatocytes, p38α knockdown DU145 displayed much higher levels of E-cadherin, especially in the rim of cells. Additionally, both p38 inhibitor SB202580 and p38α siRNA transfected cells expressed higher E-cadherin than control in DU145. Taken together, hepatocytes regulate PCa cells to undergo MET via suppressing p38 MAPK activity in the cancer cells.

Citation Format: Bo Ma, Alan Wells. The mechanism of mesenchymal-to-epithelial transition driven by hepatocytes in prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2820. doi:10.1158/1538-7445.AM2013-2820
Abstract 2859: Differential effects of specific dietary fat sources on inflammation and intestinal tumorigenesis.
Authors: Doerner Stephanie K. , Leung Elaine S. , Ko Justine S. , Nadeau Joseph H. , Berger Nathan A.
Published: August 2014

Diet-induced obesity (DIO) and metabolic syndrome (MetS) are important factors that contribute to the development and progression of cancer, especially colon cancer. DIO and MetS have reached epidemic proportions in the United States and are heavily influenced by diets high in saturated and omega-6 polyunsaturated fatty acids. Using the ApcMin/+ model of intestinal neoplasia and diets constructed from 58% coconut, corn or olive oils, we demonstrate that high amounts of dietary fats can have differential effects on DIO and MetS, as well as on intestinal tumorigenesis when compared to ApcMin/+ fed corresponding calorically equivalent control diets that contained 10% fat from these same sources. Specific sources of dietary fat lead to more rapid tumor progression, elevated polyp number and mass, as well as increased mortality, thus eliciting a detrimental impact on disease outcome, while others fail to induce an increase in polyp burden and reduce cancer severity in mice with genetic predisposition to intestinal neoplasia. We demonstrate that the tumor promoting effects of different fats are associated with systemic and local intestinal inflammation and that excess nutritional richness from specific sources can increase pro-inflammatory factors such as IL-6, IL-1β, TNFα, COX-2. Adipokines, such as adiponectin and leptin, are differentially modulated in response to different fat sources. Short (3 day) dietary exposure is sufficient to induce inflammation and tumorigenesis before the onset of DIO or MetS, suggesting a potent effect of diet on intestinal immunity. Additionally, we demonstrate a novel mechanism for the innate immunity in diet-induced intestinal cancer. We show that pharmacological and genetic inhibition of innate immunity factors can significantly reduce polyp number and mass in ApcMin/+. These results suggest that nutritional modification may be a useful approach to alter intestinal and systemic inflammation with potential preventative value for use in colon tumorigenesis and that diet, immunity and cancer are intrinsically related.

Citation Format: Stephanie K. Doerner, Elaine S. Leung, Justine S. Ko, Joseph H. Nadeau, Nathan A. Berger. Differential effects of specific dietary fat sources on inflammation and intestinal tumorigenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2859. doi:10.1158/1538-7445.AM2013-2859
Abstract 2860: A critical role of bone marrow-derived cells for hedgehog-mediated carcinogenesis.
Authors: Xie Jingwu , Fan Eric Qipeng , Gu Dongsheng , Liu Hailan , Zhang Xiaoli , Kaplan Mark , Yoder Merv
Published: August 2014

Amounting evidence indicate that the tissue microenvironment in a developing tumor is created by the tumor to orchestrates molecular and cellular interactions. As a major pathway involved in tumorigenesis, Hedgehog (Hh) signaling is known to regulate tumor microenvironment, but the underlying molecular mechanisms in hedgehog-driven tumors remain unclear. Here we show that smoothened (SMO)-mediated tumor development is accompanied by TGFβ activation in a variety of cell types of the tumor microenvironment, such as keratinocytes, fibroblasts and myeloid-derived suppressor cells. To determine the role of TGFβ signaling for SMO-mediated tumor development, we generated cell type specific TGFβR2flp/flp mice in which SmoM2 expression is accompanied by TGFβR2 knocking out. We found that while K14cre-mediated TGFβRII knockout promoted tumor development, Mx-1cre-mediated TGFβRII knockout suppressed tumor development, indicating a tumor promoting effect of stromal TGFβ signaling. Using EGFP expressing mice for bone marrow transplantation, we determined that most stromal cells with TGFβ signaling activation are derived from bone marrow. To further determine the role of stromal TGFβ signaling for hedgehog signaling-mediated tumor development, we performed bone marrow transplantation experiments in mice that can be induced to develop basal cell carcinomas (BCC). We found that bone marrow cells with TGFβR2 knockout, but not the wild type cells, inhibited tumor development and reduced the size of developed tumors. Reduction of tumor development was associated with decreased expression of multiple inflammation stimulatory cytokines as well as the number of myeloid-derived suppressor cells (MDSCs). The tumor promoting effect of TGFβ signaling is not limited to BCC because tumor growth of B16-F10 cells was also affected by TGFβRII elimination in bone marrow-derived cells. Our data indicate that TGFβ signaling in the tumor microenvironment, not in the keratinocytes, is critical for maintaining the tumor microenvironment to foster tumor development and growth.

Citation Format: Jingwu Xie, Eric Qipeng Fan, Dongsheng Gu, Hailan Liu, Xiaoli Zhang, Mark Kaplan, Merv Yoder. A critical role of bone marrow-derived cells for hedgehog-mediated carcinogenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2860. doi:10.1158/1538-7445.AM2013-2860
Abstract 2863: RNase-L modulates the immune response to intestinal damage and ameliorates murine colitis and colitis-associated cancer.
Authors: Long Tiha M. , Chakrabarti Arindam , Ezelle Heather , Brennan-Laun Sarah , Raufman Jean-Pierre , Polyakova Irina , Silverman Robert , Hassel Bret
Published: August 2014

The endoribonuclease RNase-L is a Type-I interferon (IFN)-regulated component of the innate immune response that functions in antiviral and antibacterial activities. Here we identify a protective role for RNase-L in the inflammatory response to gastrointestinal (GI) injury and commensal bacteria. In a dextran sulphate sodium (DSS)-induced model of ulcerative colitis RNase-L-/- mice exhibited a more severe clinical score and increased mortality compared to wild type animals. The enhanced sensitivity to GI damage was accompanied by delayed leukocyte infiltration and reduced expression of the proinflammatory cytokines IFNβ, TNFα, IL-1β and IL-18 at early times post-DSS exposure. This impaired innate immune response corresponded with increased inflammation and a decreased capacity to recover from GI injury at later times. Consistent with the established role of inflammation as a risk factor for colorectal cancer, in a model of colitis-associated cancer DSS treated RNase-L-/- mice displayed an increased carcinogen-induced tumor burden and mortality. A potential mechanism by which RNase-L functions in the response to GI damage and commensal bacteria is via the production of RNA agonists of RIG-I-like receptors (RLRs), sensors of cytosolic pathogen-associated RNAs that initiate signaling to induce proinflammatory cytokines important to GI homeostasis. Indeed, we found that bacterial RNA triggers IFNβ induction in macrophages in an RNase-L-dependent manner. Together, these results support a model in which the protective role for RNase-L in experimental colitis and colitis-associated cancer occurs through RNase-L-dependent RLR signaling and IFNβ induction.

Citation Format: Tiha M. Long, Arindam Chakrabarti, Heather Ezelle, Sarah Brennan-Laun, Jean-Pierre Raufman, Irina Polyakova, Robert Silverman, Bret Hassel. RNase-L modulates the immune response to intestinal damage and ameliorates murine colitis and colitis-associated cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2863. doi:10.1158/1538-7445.AM2013-2863
Abstract 2869: Interaction between a COX2 polymorphism and ER status in relation to risk for early events in breast cancer patients.
Authors: Markkula Andrea , Simonsson Maria , Ingvar Christian , Rose Carsten , Jernström Helena C.
Published: August 2014

Background. Cyclooxygenase-2 (COX2) polymorphisms are associated with cancer in the lung, colorectum, and breast. In several studies, the COX2 rs5277 variant has been implicated in cancers associated with inflammation. COX-2 is the rate-limiting enzyme in the production of the pro-inflammatory prostaglandin, which activates CYP19 transcription and increases CYP19 (aromatase) levels, the key enzyme in androgen to estrogen conversion. The aim of this study was to investigate whether associations between the COX2 rs5277 polymorphism and early breast cancer events vary according to ER-status. Methods. COX2 rs5277 (306G>C, V102V) was genotyped with PCR based methods in 634 breast cancer patients in a population-based ongoing cohort from southern Sweden. Clinical data were obtained from patient charts and pathology reports. Rs5277 was examined in relation to patient, tumor characteristics and early events. Results. Minor allele frequency was 16.1%. Rs5277 was not associated with patient or tumor characteristics. Median follow-up was 4.92 years in patients with invasive tumors. Overall, increasing number of C-alleles was not associated with early events (Log Rank 1df; p=0.35). However, after stratification according to ER status, increasing number of C-alleles was associated with a fewer early events in the 73 patients with ER-negative tumors (Log Rank 1df; p=0.029) and borderline associated with more early events among the among the 497 patients with ER-positive tumors (Log Rank 1df; p=0.081). The interaction between ER-status and COX2 rs5277 on early events was significant (pinteraction=0.010). In a multivariate model among patients with ER-positive tumors, a CC genotype predicted an increased risk for early events (HR 4.25; 95 %CI 1.18-15.29; p=0.027), adjusted for tumor size (pT), nodal involvement, age, and histological grade. None of the patients with a CC genotype and an ER-negative tumor had a breast cancer event during the follow-up. Conclusion. The results indicate that the association between the COX2 rs5277 polymorphism and early breast cancer events varies according to ER-status. Information on rs5277 genotype may provide additional prognostic information for individual breast cancer patients.

Citation Format: Andrea Markkula, Maria Simonsson, Christian Ingvar, Carsten Rose, Helena C. Jernström. Interaction between a COX2 polymorphism and ER status in relation to risk for early events in breast cancer patients. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2869. doi:10.1158/1538-7445.AM2013-2869
Abstract 2896: Genomic determinants and signature of MET-targeted therapy in glioblastoma.
Authors: Xie Qian , Johnson Jennifer , Ascierto Maria Libera , Kang Liang , Bradley Robert , Mittal Sandeep , Furge Kyle , Briggs Michael , Tanner Kirk , Berens Michael E. , Marincola Francesco M. , Vande Woude George F.
Published: August 2014

Glioblastoma (GBM) is one of the most devastating cancers, because the intrinsic capability of single tumor cells to invade normal brain impedes surgical eradication, predictably resulting in early local recurrence and death. The goal of this study is to develop therapeutic strategies for treating GBM patients by identifying and targeting the molecular mechanisms of GBM invasiveness through inhibiting MET signaling pathway. Overexpression of hepatocyte growth factor (HGF) and its receptor MET are associated with poor prognosis of GBM. Genomic analysis of primary GBM tumors indicates that MET is overexpressed in tumors of the mesenchymal phenotype, which is more invasive and results in short patient survival. More recently, MET activation was found to contribute to recurrence in GBM patients after bevacizumab treatment, further highlighting the utility of blocking the MET pathway in this disease. With MET inhibitors’ entering clinical trials, there is increased need to find the molecular determinants of MET sensitivity. Because GBM is a heterogeneous disease in which drug response in the individual patient can be regulated by different mechanisms, approaches for understanding and predicting treatment outcomes based on the molecular features of individual tumor will be of a high value. Based on our previous finding that HGF-autocrine activation predicts sensitivity to MET inhibition, we have developed a two-step methodology using microarray technology and bioinformatics analysis to identify and test genomic determinants in order to effectively deploy MET-targeted therapy in GBM patients. By analyzing the data sets from The Cancer Genome Atlas Network (TCGA) and those from GBM xenograft models sensitive and insensitive to MET inhibitors, a 25-gene signature highly associated with HGF-autocrine activation is identified. When performing validation analysis, the signature scored 40 human GBM xenograft models by HGF expression level, providing a good rationale for further testing its predictive value in identifying tumors sensitive to MET inhibitors. We conclude that HGF-autocrine activation can result in oncogene addiction to MET signaling in GBM. Via a unique panel of signature genes we may be able to identify a subset of patients vulnerable to anti-MET drugs.

Citation Format: Qian Xie, Jennifer Johnson, Maria Libera Ascierto, Liang Kang, Robert Bradley, Sandeep Mittal, Kyle Furge, Michael Briggs, Kirk Tanner, Michael E. Berens, Francesco M. Marincola, George F. Vande Woude. Genomic determinants and signature of MET-targeted therapy in glioblastoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2896. doi:10.1158/1538-7445.AM2013-2896
Abstract 291: ERK1/2 pathway activation controls epithelial-mesenchymal transition in NSCLC cells.
Authors: Buonato Janine M. , Lazzara Matthew J.
Published: August 2014

Understanding and overcoming the cellular mechanisms that underlie de novo and acquired therapy resistance remains a challenge in treating many cancers including non-small cell lung cancer (NSCLC). Despite the prevalence of epidermal growth factor receptor (EGFR) over-activation in NSCLC and other cancers, most patients are resistant to EGFR inhibitors. A number of studies have linked mesenchymal cellular phenotypes and epithelial-mesenchymal transition (EMT) with resistance to chemotherapeutics and EGFR inhibitors across cancer types. Here, we demonstrate in NSCLC cells that MAPK/ERK signaling plays a key role in determining mesenchymal cellular characteristics and response to the EGFR inhibitor gefitinib. In cultured NSCLC cell lines, pharmacological inhibition of MEK pushed cells toward a more epithelial phenotype and prevented EMT induction by exogenous transforming growth factor beta. In addition, chronic MEK inhibition synergistically enhanced cellular sensitivity to gefitinib in a reversible manner and slowed cell migration in wound healing assays in NSCLC cell lines with both de novo and acquired resistance to gefitinib. Importantly, our results demonstrate that the observed cell phenotypic changes occur on a time scale corresponding to that with which epithelial and mesenchymal marker expression change in response to ERK inhibition. This time scale is much larger than that for changes in ERK activity itself, reflecting the need for downstream ERK-dependent processes to affect phenotypic changes. Changes in the same cellular phenotypes and associated changes in epithelial and mesenchymal markers also occurred as a result of KRAS mutant expression in a MEK-dependent manner. Overall, this study draws a strong connection between ERK pathway activation and mesenchymal characteristics in NSCLC and suggests potential new opportunities for expanding the efficacy of currently available EGFR inhibitors.

Citation Format: Janine M. Buonato, Matthew J. Lazzara. ERK1/2 pathway activation controls epithelial-mesenchymal transition in NSCLC cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 291. doi:10.1158/1538-7445.AM2013-291
Abstract 2957: Cellular level of HSP27 phosphorylation plays a key switch from cell survival to death induced by TRAIL or gemcitabine.
Authors: Kang Dongxu , Choi Hye J. , Kim Jina , Kim Joo-Hang , Song Jae Jin
Published: August 2014

TRAIL-induced activation of Akt catalytic activity and phosphorylation were highly correlated with p38/HSP27 phosphorylation, whereas the phosphorylation of p38/HSP27 increased further during incubation with curcumin and TRAIL, which caused significant apoptotic cell death in DU-145 cells. Next, we investigated whether the cellular level of HSP27 phosphorylation acts as a determinant of cell fate: from cell survival to cell death by biphasic way using another anticancer agent, gemcitabine an antitumor drug currently used for the treatment of advanced pancreatic cancer. We have observed that gemcitabine induced p38/HSP27 phosphorylation and acquired resistance at lower concentration as TRAIL did. After the acquisition of TRAIL or gemcitabine resistance, cancer cells (DU-145 or Mia-PaCa) with acquired resistance to these drugs expressed higher amount of vimentin as well as various MMPs. However, the expression level of these proteins even in TRAIL or gemcitabine-resistant cells was significantly decreased by the incorporation of constitutively phospho-mimic HSP27 with concurrent cell death, providing a new potential strategy to overcome the drug resistance and ultimate metastasis.

Citation Format: Dongxu Kang, Hye J. Choi, Jina Kim, Joo-Hang Kim, Jae Jin Song. Cellular level of HSP27 phosphorylation plays a key switch from cell survival to death induced by TRAIL or gemcitabine. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2957. doi:10.1158/1538-7445.AM2013-2957
Abstract 3018A: A novel type of oncogene SWAP-70.
Authors: Shu Chung-Li , Lai Jing-Yang , Su LIang-Cheng , Chuu Chih-Pin , Fukui Yasuhisa
Published: August 2014

SWAP-70 is a protein that has been suggested to be involved in regulation of actin rearrangement. Having found that an artificial mutant of SWAP-70 can transform mouse embryo fibroblasts, we searched for mutations of the SWAP-70 gene, finding listings for several on the Web at www.sanger.ac.uk/genetics/CGP/cosmic/, including three mutations in ovarian cancers. (The number of such mutations has now reached seven.) We made expression vectors for the mutant SWAP-70 proteins and introduced into NIH3T3 cells. The cells expressing the mutant SWAP-70 exhibited faster growth than the parental or wild type SWAP-70-expressing cells. That these cells grew in soft agar suggests they may be malignant tumor cell lines. They were sensitive to nutrient starvation, supporting the idea that they are transformed cells. However, they failed to pile up and showed contact inhibition, unlike usual transformed cells. Upon expression of human SWAP-70 genes, MEK was activated. This activation appeared to contribute to the saturation density of the cells. Because SWAP-70 has been shown to be the last protein to receive signals from cytokines, it is likely that there is a feedback signaling pathway and that disorder of this signaling pathway can transform the cells.

Citation Format: Chung-Li Shu, Jing-Yang Lai, LIang-Cheng Su, Chih-Pin Chuu, Yasuhisa Fukui. A novel type of oncogene SWAP-70. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3018A. doi:10.1158/1538-7445.AM2013-3018A
Abstract 3120: Evidence supporting a role of ETV4 in pancreatic cancer pathogenesis.
Authors: Srivastava Sanjeev K. , Tyagi Nikhil , Kaur Gurpreet , Arora Sumit , Bhardwaj Arun , Grizzle William E. , Singh Ajay P. , Singh Seema
Published: August 2014

The clinical outcome from pancreatic cancer has not improved over the years. This is, in part, due to not well understood disease mechanisms and consequently there is little progress made in developing intervention therapy. Many genetic alterations have been characterized in pancreatic cancer, of which some have been shown to be functionally relevant. ETV4, proto-oncogenic transcription factor, has been shown to be aberrantly expressed in various cancers types and plays important role in disease pathogenesis. The role of ETV4, however, has not been defined in pancreatic cancer so far. In this study, we investigated the pathological involvement of ETV4 in pancreatic cancer. For this, we silenced its expression in two highly tumorigenic and metastatic ETV4 overexpressing pancreatic cancer cell lines (Colo357 and ASPC1) by stable transfection of ETV4-targeted short-hairpin RNA (shRNA)-expression plasmid. Silencing of ETV4 led to a decrease in growth and clonogenicity of ETV4-silenced pancreatic cancer cells (Colo357-shETV4 and ASPC1-shETV4) as compared to their respective controls (Colo357-Scr and ASPC1-Scr). Furthermore, inhibition of ETV4 also caused suppression of pancreatic cancer cell motility and invasiveness. In contrast, ETV4-silenced pancreatic cancer cells exhibited greater cell-cell interaction as compared to their respective control cells. Immunoblot analyses demonstrated a loss of mesenchymal markers, N-cadherin, Vimentin, and twist, and gain of epithelial marker, E-cadherin, in ETV4-silenced Colo357 and ASPC1 cells, indicating a role of ETV4 in epithelial to mesenchymal transition (EMT) of PC cells. Lastly, expression analysis of ETV4 in clinical specimens demonstrated its aberrant expression in malignant pancreatic tissue, while no expression was detected in the normal pancreas. Altogether, these findings provide first experimental evidence for a functional role of ETV4 in pancreatic cancer.

Citation Format: Sanjeev K. Srivastava, Nikhil Tyagi, Gurpreet Kaur, Sumit Arora, Arun Bhardwaj, William E. Grizzle, Ajay P. Singh, Seema Singh. Evidence supporting a role of ETV4 in pancreatic cancer pathogenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3120. doi:10.1158/1538-7445.AM2013-3120
Abstract 3290: Modulation of AKT, ERK and Mcl-1 by apigenin sensitizes colon cancer cells to anti-tumor activities of ABT263.
Authors: Shao Huanjie , Jing Kai , Mahmoud Esraa , Fang Xianjun , Yu Chunrong
Published: August 2014

Apigenin is an edible plant-derived flavonoid showing anti-tumor activities in vitro and in vivo.

Pretreatment with apigenin resulted in cell growth arrest and/or apoptosis in various types of tumors via modulating multiple cell signaling pathways. In the present study, we evaluated interactions between apigenin and ABT263 in multiple colon cancer cell lines. We found that apigenin enhanced ABT263-induced apoptosis in colon cancer cells in a time- and dose-dependent manner. ABT263 alone only resulted in limited cell killing in association with upregulation of Mcl-1, a potential mechanism for acquired ABT263 resistance. Apigenin antagonized ABT263-induced Mcl-1 expression and dramatically enhanced ABT263-induced cell death. Apigenin also suppressed AKT and ERK activation. Inactivation of either AKT or ERK pathway by lentivirus-transduced shRNA or specific small molecule inhibitors synergized with ABT263 to induce cell death, reflecting that AKT and ERK pathways are apigenin targets. Moreover, the synergism between ABT263 and apigenin was associated with the upregulation of Bim and subsequent activation of Bax. Xenograft studies with HCT116 cells in SCID mice showed that the combination treatment with apigenin and ABT263 inhibited tumor growth up to 70% without obvious adverse effects, while either agent alone showed only about 30% inhibition. Collectively, our findings demonstrate a novel and effective strategy to treat colon cancer by combination of ABT263 and apigenin. The combined effect is mediated by apigenin downregulation of Mcl-1, Akt and ERK activities.

Citation Format: Huanjie Shao, Kai Jing, Esraa Mahmoud, Xianjun Fang, Chunrong Yu. Modulation of AKT, ERK and Mcl-1 by apigenin sensitizes colon cancer cells to anti-tumor activities of ABT263. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3290. doi:10.1158/1538-7445.AM2013-3290
Abstract 3295: Combining GSK3 inhibition and Vitamin D as a differentiation strategy for AML.
Authors: Gupta Kalpana , Stefan Tammy , Wald David N.
Published: August 2014

Vitamin D has widely been considered a promising therapy for cancer, particularly Acute Myeloid Leukemia (AML), due to its ability to terminally differentiate leukemic cells. Despite the promise of Vitamin D in preclinical studies, clinical trials have been disappointing likely due to dose limiting hypercalcemia that occurs at relatively low doses. We have identified that the kinase GSK3 is a major regulator of the Vitamin D receptor (VDR) and that targeting GSK3 can sensitize leukemic cells to low concentrations of Vitamin D that may be achievable clinically.

Utilizing cell and animal based models, we found that GSK3 inhibition can significantly enhance the anti-leukemic effects of Vitamin D. By inhibiting GSK3 with both small molecules and shRNA, we found that targeting GSK3 leads to a significant sensitization in AML cells derived from multiple AML subtypes to Vitamin D-mediated differentiation. Differentiation induction can be seen through immunophenotyping for cell surface markers, functional differentiation as measured by NBT reduction, and changes in morphology. For example, treatment of HL-60 cells with low doses of Vitamin D (5nM) or a GSK3 inhibitor SB415286 (10uM) leads to only moderate differentiation (<50%) while the combination of these agents leads to greater than 95% differentiation as measured by the upregulation of the differentiation associated marker, CD11b. In addition to differentiation induction, GSK3 inhibition also significantly enhanced the ability of Vitamin D to cause irreversible growth inhibition as measured by colony assays and slowed the progression of AML in a mouse model system.

Mechanistic studies have revealed significant insights into how GSK3 modulates Vitamin D signaling. GSK3 was found to bind and phosphorylate VDR which negatively regulates VDR activity as measured by luciferase based reporter assays. The mechanism through which GSK3 appears to regulate VDR activity is through impacting its interactions with co-repressors and co-activators. These co-modulators are known to play a predominant role in regulating VDR activity. Utilizing co-immunoprecipitation and mammalian two hybrid assays, we determined that GSK3 inhibition can impair the interaction of VDR with the co-repressor NcoR, and enhance its interaction with the co-activator, SRC-3. Overall, our studies suggest the potential of Vitamin D and GSK3 inhibition as a strategy to improve the efficacy of AML treatment and provide a mechanistic framework to explain the promising activity of this combination regimen.

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Citation Format: Kalpana Gupta, Tammy Stefan, David N. Wald. Combining GSK3 inhibition and Vitamin D as a differentiation strategy for AML. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3295. doi:10.1158/1538-7445.AM2013-3295
Abstract 3416: Genomic alterations of the CDK4-pathway in melanoma and evaluation of the CDK4 Inhibitor PD-0332991.
Authors: Sheppard Karen E. , Foo Allen , Young Richard , Waldeck Kelly , Pearson Richard , McArthur Grant , Christensen James
Published: August 2014

Activation of CDK4 by amplification, increased expression of Cyclin D1 (CCND1) or reduced expression of the CDK inhibitor p16 (CDKN2A) can contribute to melanocyte transformation, indicating that CDK4 can act as an oncogene in melanoma. We have analyzed the frequency of gene copy number variations (CNV) in the CDK4 pathway and looked for associations of these alterations with patient survival to assess if CDK4 is a viable target for the treatment of human melanoma. In addition, we screened a panel of melanoma cells with a highly selective CDK4/6 inhibitor PD-0332991 (PD-991) and performed gene expression and mutation analysis on these cells to explore possible genomic predictors of sensitivity.

Genomic analysis revealed that 75% of primary melanomas had at least one CNV in the CDK4 pathway, with 55% showing a loss of CDKN2A. 28% of melanomas had two or more CNVs and melanomas with two or more CNVs involving CCND1 had worse overall survival (HR 5.56, P=0.02). From the cell line studies low CDKN2A mRNA expression, mutation or loss predicted sensitivity to PD-991 with 23 out of 27 mutant/loss cell lines being sensitive compared to only 3/7 wild type lines (p<0.03). Expression of CDK4, CCND1 or other cyclins or CDK-inhibitors did not predict sensitivity to PD-991. PD-991 induced an increase in both cell size and SA-ß-galactosidase activity that is indicative of a senescent phenotype, and this was associated with cells having wild type p53. In summary, genomic alterations in the CDK4 pathway are frequent in melanoma and are associated with worse survival, particularly when melanomas harbor two or more CNVs involving CCND1. CDK4 inhibition induces a senescent phenotype in melanoma cells that is associated with loss of CDKN2A and wild type TP53. Taken together these data support evaluation of CDK4 inhibitors in melanoma and suggest that CDKN2A and TP53 maybe genomic predictors of sensitivity.

Citation Format: Karen E. Sheppard, Allen Foo, Richard Young, Kelly Waldeck, Richard Pearson, Grant McArthur, James Christensen. Genomic alterations of the CDK4-pathway in melanoma and evaluation of the CDK4 Inhibitor PD-0332991. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3416. doi:10.1158/1538-7445.AM2013-3416
Abstract 3592: Roles of miR-199a-5p and COX-2 in arsenic-induced tumor angiogenesis.
Authors: He Jun , Carpenter Richard , Jiang Yue , Xu Qing , Jiang Bing-Hua
Published: August 2014

Arsenic is a well-known human carcinogen which is closely associated with lung cancer. However, the mechanism underlying the arsenic-induced carcinogenesis remains to be elucidated. The alterations of miRNAs profiles in cancers have profound implication in cancer development. However, it remains to be determined whether the alterations of miRNA signature in response to carcinogens such as arsenic may result in cell malignant transformation and tumor growth. In this study, we developed an in vitro model by transforming human lung epithelial BEAS-2B cells through long-term exposure to low concentration of arsenic. The BEAS-2B cells were malignantly transformed validated by cell proliferation, anchorage independent growth and tumor growth assay. By utilizing this model, we found that miR-199a-5p expression level was dramatically repressed in arsenic-transformed cells. Re-expression of miR-199a-5p impaired arsenic-induced tumor angiogenesis through directly targeting hypoxia inducible factor-1α (HIF-1α). Interestingly, we found another proangiogenic factor cyclooxygenase-2 (COX-2) that was also upregulated in arsenic-transformed cells and was predicted as a target of miR-199a-5p. It was confirmed by generating COX-2 3’UTR miRNA luciferase reporters with wild-type or mutant binding sites with miR-199a-5p. Overexpression of miR-199a-5p inhibited COX-2 protein expression. Functional study revealed that knockdown of COX-2 by siRNA in arsenic-transformed cells decreased tumor angiogenesis. We further showed that the COX-2 promoter contains a functional hypoxia response element (HRE). HIF-1α regulated COX-2 expression at the transcriptional level via direct binding to the HRE (-576/-584) located within the COX-2 promoter. Thus, arsenic-induced COX-2 activation is mediated by repression of miR-199a-5p and activation of HIF-1. Moreover, prostaglandin E2 (PGE2), a product of COX-2 regulated HIF-1 expression in a positive-feedback manner. In addition, arsenic-transformed cells have high levels of reactive oxygen species (ROS) for activating COX-2 pathway. Taken together, our results demonstrate that arsenic-induced angiogenesis through miR-199a-5p repression and pro-inflammatory responses induced by ROS. Both pathways lead to activation of HIF-1/COX-2 pathway. These findings establish critical roles of miR-199a-5p and its downstream targets HIF-1/COX-2 in arsenic-induced tumor angiogenesis. As miR-199a-5p is generally downregulated, whereas COX-2 is overexpressed in human lung cancer tissues, they may be used as new therapeutic targets for lung cancer treatment in the future.

Citation Format: Jun He, Richard Carpenter, Yue Jiang, Qing Xu, Bing-Hua Jiang. Roles of miR-199a-5p and COX-2 in arsenic-induced tumor angiogenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3592. doi:10.1158/1538-7445.AM2013-3592
Abstract 361: ZNF24 may modulate microvascular endothelial cell invasion by regulating MMP2 transcription.
Authors: Jia Di , Moses Marsha A.
Published: August 2014

ZNF24 is a C2H2 zinc finger transcription factor that regulates angiogenesis by repressing the transcription of vascular endothelial growth factor (VEGF). It has also been implicated in the control of cell proliferation and differentiation in the central nervous system and in hepatocellular carcinoma. In the current study, we have focused on the role of ZNF24 in modulating endothelial cell motility. We have found that silencing of ZNF24 in human microvascular endothelial cells (HMVEC) leads to significantly decreased cell migration and invasion. Consistently, the protein level and proteolytic activity of matrix metalloproteinase-2 (MMP2), but not those of matrix metalloproteinase-9 (MMP9), are significantly downregulated when ZNF24 is silenced in these cells. We have also determined the effect of ZNF24 silencing on the mRNA levels of endogenous inhibitors of MMPs, the tissue inhibitors of metalloproteinases (TIMPs). While TIMP1 and TIMP4 levels are moderately upregulated by ZNF24 silencing, the level of TIMP2, a major regulator of MMP2 proteolytic activity, and that of TIMP3, are significantly decreased. However, ZNF24 siRNA induces only a moderate decrease in the protein level of TIMP2, suggesting that TIMP2 does not play an important role in the regulation of MMP9 activity by ZNF24. Another major regulator of MMP2 proteolytic activity, membrane-type-1 matrix metalloproteinase (MT1-MMP), also does not exhibit significant changes when ZNF24 is silenced, suggesting that MMP2 is regulated by ZNF24 at the transcriptional level. Indeed, the mRNA level of MMP2 is significantly downregulated when cells are transfected with ZNF24 siRNA, indicating that ZNF24 positively regulates the transcription of MMP2. When compared to normal endothelial cells, tumor endothelial cells exhibit higher levels of endogenous ZNF24, suggesting that ZNF24 may function to increase cell invasion in these cells via upregulation of MMP2. Our current studies are focused on determining whether MMP2 is a direct downstream target of ZNF24 as well as on its role(s) in modulating endothelial cell motility in vivo. (Supported by NIH P01 CA045548, the Breast Cancer Research Foundation and the Advanced Medical Research Foundation)

Citation Format: Di Jia, Marsha A. Moses. ZNF24 may modulate microvascular endothelial cell invasion by regulating MMP2 transcription. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 361. doi:10.1158/1538-7445.AM2013-361