bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 890: Effects of Lewis lung carcinoma on trabecular microstructural changes in wild-type and plasminogen activator inhibitor-1 deficient mice fed a high-fat diet
Authors: Yan Lin
Published: August 2015

Bone is a major target organ of metastasis. The present study investigated the effects of Lewis lung carcinoma (LLC) on trabecular microstructural changes, using tomographic analysis, in distal femur and lumbar 4 vertebra from LLC-bearing wild-type and plasminogen activator inhibitor-1 (PAI-1) deficient mice (C57BL/6J background) fed the AIN93G diet or a high-fat diet; a group of AIN93G-fed non-tumor-bearing wild-type mice were used as controls. Compared to AIN93G-fed non-tumor-bearing wild-type mice, LLC significantly reduced bone volume fraction (BV/TV), connective density (Conn.D), trabecular number (Tb.N), trabecular thickness (Tb.Th) and bone mineral density (BMD) and significantly increased trabecular separation (Tb.Sp) in distal femurs of AIN93G-fed wild-type mice. In high-fat diet-fed mice, compared to the AIN93G-fed ones, LLC resulted in significantly greater reductions BV/TV, Conn.D, Tb.N and BMD and significantly greater increases in structure model index (SMI) and Tb.Sp. Deficiency in PAI-1, compared to wild-type mice, significantly increased BV/TV, Conn.D, Tb.N and significantly reduced SMI. In vertebra, LLC resulted in similar trabecular changes compared to the non-tumor-bearing wild-type controls, the high-fat diet reduced BV/TV and BMD and increased SMI, whereas PAI-1 deficiency did not affect trabecular microstructure in vertebrae. These results demonstrated (1) that LLC is detrimental to trabecular bone which may make it more vulnerable to malignant invasion, (2) that high-fat diet enhances LLC-induced trabecular deterioration and (3) that the improvement in trabecular microstructure by PAI-1 deficiency indicates that PAI-1 may play a role in trabecular microarchitectural deterioration during malignant progression.

Citation Format: Lin Yan. Effects of Lewis lung carcinoma on trabecular microstructural changes in wild-type and plasminogen activator inhibitor-1 deficient mice fed a high-fat diet. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 890. doi:10.1158/1538-7445.AM2015-890
Abstract 902: RNA-Seq profiling of silibinin effects on bladder cancer cells
Authors: Yamamura Soichiro , Mitsui Yozo , Bucay Nathan , Saini Sharanjot , Majid Shahana , Deng Guoren , Shahryary Varahram , Dahiya Rajvir , Tanaka Yuichiro
Published: August 2015

Silibinin is the major active constituent of silymarin, an extract of the milk thistle seeds, containing a mixture of flavonolignans such as silibinin and isosilibinin. Silibinin has been shown to have significant anti-cancer effects in a variety of cancer types, including bladder, kidney, prostate, skin, breast, lung and colon cancer. Silibinin (10 μM) significantly suppressed proliferation and invasion of T24 and UM-UC-3 bladder cancer cells. Western blot analysis showed that silibinin significantly reduces expression of vimentin and slug in these bladder cells. Vimentin is overexpressed in various cancers and is known to promote tumor growth, invasion, and poor prognosis. Slug, a transcriptional repressor which mediates epithelial to mesenchymal transition (EMT), has been implicated in tumor metastasis. These results indicate that silibinin inhibits proliferation and invasion by suppressing vimentin and slug in bladder cancer cells. We studed the anti-cancer effects of silibinin in bladder cancer cells using RNA-Seq, a transcriptome profiling technique that uses deep-sequencing to quantitatively investigate the global behavior of transcriptomes. We will discuss the RNA-Seq profiling of the anti-cancer effects of silibinin in bladder cancer cells, including the vimentin and slug networks.

Citation Format: Soichiro Yamamura, Yozo Mitsui, Nathan Bucay, Sharanjot Saini, Shahana Majid, Guoren Deng, Varahram Shahryary, Rajvir Dahiya, Yuichiro Tanaka. RNA-Seq profiling of silibinin effects on bladder cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 902. doi:10.1158/1538-7445.AM2015-902
Abstract 905: Influence of high fat diet and APC status on epigenetic regulation of FXR in colon cells
Authors: Selmin Ornella I. , Lyon Adam M. , Fang Changming , Doetschman Tom C. , Thompson Patricia A. , Martinez Jesse D. , Smith Jeffrey , Lance Peter M. , Romagnolo Donato F.
Published: August 2015

Bile acids (BAs) not recycled through the enterohepatic system can be modified in the colon into cancer-promoting secondary BAs such as deoxycholic acid (DCA). The farnesoid-X-receptor (FXR) regulates hepatic and intestinal BA homeostasis. However, in intestinal cells carrying defective adenomatous polyposis coli (Apc) gene the expression of FXR is reduced through yet unknown mechanisms. To investigate if Western high-fat diet (HFD) and Apc status influence epigenetic regulation of the Fxr in colonic mucosa. Weaned C57BL/6J male mice were fed a HFD (22% safflower oil = SO) or control low fat diet (LFD; 5% SO) for 6 wks. We examined the effects on CpG pmethylation of Fxr, and expression of FXR, peroxisome-proliferator activated receptor-gamma (PPARγ), and cyclooxygenase-2 (COX-2) mRNA. Also, we studied the influence of APC status on CpG methylation of the Fxr gene, and expression of FXR, ileal bile acid-binding protein (IBABP), small heterodimer partner (SHP), and COX-2 mRNA in normal colonic mucosa and colon tumors from APCMin/+ mice. Mice fed the HFD had reduced (60%) Fxr promoter methylation and increased (2∼3-fold) FXR, COX-2, and PPARγ mRNA levels. Conversely, APC-deficiency was associated with constitutive hypermethylation of the Fxr gene, elevation of COX-2, and reduced (60-90%) baseline FXR, IBABP, and SHP mRNA. In human HCT-116 colon cells, siRNA knock-down of APC reduced (50%) basal FXR mRNA expression, which was further reduced to 80% by DCA. We conclude that APC deficiency leads to constitutive epigenetic silencing of Fxr increasing the risk of inflammation and colon cancer associated with a Western HFD.

Note: This abstract was not presented at the meeting.

Citation Format: Ornella I. Selmin, Adam M. Lyon, Changming Fang, Tom C. Doetschman, Patricia A. Thompson, Jesse D. Martinez, Jeffrey Smith, Peter M. Lance, Donato F. Romagnolo. Influence of high fat diet and APC status on epigenetic regulation of FXR in colon cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 905. doi:10.1158/1538-7445.AM2015-905
Abstract 933: Circulating biomarkers of B vitamins in relation to lung cancer risk in the Lung Cancer Cohort Consortium
Authors: Fanidi Anouar , Muller David.C , Prentice Ross , Demetrius Albanes , Yuan Jian-Min , Stevens Victoria , Weinstein Stephanie J , Johansson Mattias , Brennan Paul ,   Lung Cancer Cohort Consortium (LC3)
Published: August 2015

Background - B vitamins and factors related to one-carbon metabolism help to maintain DNA and regulate gene expression. Some epidemiological data suggest that factors related to the one-carbon metabolism are important in the pathogenesis of several cancers, including lung cancer.

Methods - Within the NCI Cohort Consortium, we designed a prospective case-control study including a total of 5,546 case-control pairs nested within 20 prospective cohorts. Centralized biochemical analyses of all study participants were performed to measure circulating concentrations of vitamin B6, folate and methionine, which were subsequently evaluated in relation to lung cancer risk using conditional logistic regression models.

Results - We observed an overall increased risk of lung cancer of 25% among study participants having a deficiency in circulating B6 concentrations compared to those with normal concentrations, the odds ratio (OR) being 1.23 95% confidence interval [CI] = 1.10 - 1.38. This association was primarily evident seen among men (OR 1.38 95% CI 1.20 - 1.60), but not among women (OR 1.03 95% CI 0.85-1.24), as well as for ever ever smokers (OR 1.32 95% CI 1.10 - 1.60). Subgroup analyses by histological sub-site indicated particularly strong association for squamous cell carcinoma type, with about 50% risk increase overall when comparing subjects with vitamin B6 deficiency to normal levels. No association was evident for methionine. Detailed results will be presented at the conference.

Conclusion - Our results are compatible with the hypothesis that vitamin B6 deficiency is associated with increased lung cancer risk, although the risk increase appears to be moderate.

Citation Format: Anouar Fanidi, David.C Muller, Ross Prentice, Albanes Demetrius, Jian-Min Yuan, Victoria Stevens, Stephanie J Weinstein, Mattias Johansson, Paul Brennan, Lung Cancer Cohort Consortium (LC3). Circulating biomarkers of B vitamins in relation to lung cancer risk in the Lung Cancer Cohort Consortium. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 933. doi:10.1158/1538-7445.AM2015-933
Abstract 938: Circulating biomarkers of gut barrier function: Correlates and responses to calcium supplementation among sporadic colorectal adenoma patients in a dose-response randomized controlled trial
Authors: Yang Baiyu , Bostick Roberd M. , Gewirtz Andrew T. , Tran Hao Quang , Fedirko Veronika
Published: August 2015

Gut barrier dysfunction contributes to several gastrointestinal disorders, including inflammatory bowel diseases and colorectal cancer, but factors associated with intestinal hyperpermeability have rarely been assessed in human populations, and there is very limited clinical trial evidence on whether gut barrier function may be modified by dietary factors. To address these gaps, we 1) evaluated factors associated with baseline circulating biomarkers of gut barrier function, and 2) tested the effect of calcium on these biomarkers over a 4-month treatment period among patients with previous colorectal adenoma in a randomized, double-blinded, placebo-controlled clinical trial (n = 193). Patients were randomized to placebo (n = 66), 1.0 g calcium (n = 64), or 2.0 g calcium (n = 63) daily. Circulating levels of anti-flagellin and anti-lipopolysaccharide (LPS) immunoglobulins (Igs) as markers of colonic hyperpermeability were measured at baseline and at 4-month follow-up via ELISA. At baseline, mean levels of anti-flagellin and anti-LPS IgA but not IgG were higher among men and those with a larger body mass index (BMI), a larger waist circumference, and higher levels of plasma C-reactive protein. Mean anti-flagellin IgG levels were higher among those with higher proinflammatory cytokine scores. We did not observe effects of calcium on anti-flagellin or anti-LPS Igs: the relative change of a combined permeability score (defined as the sum of the optical densities of all biomarkers) from baseline to follow-up was 0.07 (95% confidence interval [CI] -0.13, 0.27) for each treatment group relative to the placebo group (p-values ≥ 0.5). Our results suggest that 1) men and those with a larger BMI or waist circumference may have greater gut permeability, 2) markers of gut permeability and systemic inflammation may be directly associated with one another, and 3) supplemental calcium administered for 4 months may not modify circulating levels of biomarkers of gut barrier function.

Citation Format: Baiyu Yang, Roberd M. Bostick, Andrew T. Gewirtz, Hao Quang Tran, Veronika Fedirko. Circulating biomarkers of gut barrier function: Correlates and responses to calcium supplementation among sporadic colorectal adenoma patients in a dose-response randomized controlled trial. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 938. doi:10.1158/1538-7445.AM2015-938
Abstract 943: The critical role of CDK2 activation in determining the differential sensitivity of cell lines to Chk1 and Wee1 inhibitors
Authors: Sakurikar Nandini , Thompson Ruth , Montano Ryan , Eastman Alan
Published: August 2015

Anticancer DNA damaging agents activate checkpoints that halt the cell cycle to prevent further DNA replication and mitosis until the damage has been repaired. One of the important regulatory proteins activated in this pathway is Checkpoint kinase 1 (Chk1). Hence, Chk1 inhibitors have emerged as promising novel therapeutics. In clinical trials, Chk1 inhibitors are primarily being evaluated in combination with various DNA damaging agents. However, Chk1 inhibitors also show single agent activity in a subset of cell lines, and this provides a unique therapeutic opportunity to target these tumors. The goal of this study is to define the mechanism of this sensitivity, and identify biomarkers that would permit selection of appropriate patients for clinical trials. From screening a large panel of cancer cell lines, we observed that 15% were sensitive to the Chk1 inhibitor MK-8776, with rapid (<6 h) induction of DNA double-strand breaks (DSB) in S phase cells. Most of the resistant cell lines were sensitive to the Wee1 inhibitor, MK-1775 (AZD1775), while all the cell lines were sensitive to the Wee1/Myt1 dual inhibitor, PD-166285. Wee1 suppresses activation of CDK1 and CDK2, suggesting that MK-1775-mediated activation of one or other (or both) of these kinases leads to DSB. MK-8776 did not activate CDK1, so we hypothesized that activation of CDK2 was critical. To differentiate between the role of CDK1 and CDK2 in cell lines sensitive or resistant to MK-8776, we used inhibitors to CDK1/2. We found that CVT-313 was a selective inhibitor of CDK2 at low concentrations, but that Ro-3306 failed to discriminate between these two kinases in cells. CVT-313 prevented DSB and the associated phosphorylation of histone-H2AX induced by MK-8776 and MK-1775. Cyclin E is a direct target of CDK2; phosphorylation of cyclin E leads to its degradation which was only observed in sensitive cells and prior to the formation of DSB. The acute cytotoxicity was dependent on cyclin A rather than cyclin E, as siRNA-mediated knockdown of cyclin A but not cyclin E, prevented DSB. We conclude that activation of cyclin A/CDK2 determines the sensitivity of cells to MK-8776. Resistance to MK-8776 results from failure to activate CDK2, presumably through failure to activate the upstream CDC25A phosphatase. MK-1775 can circumvent this resistance by directly activating CDK2. The untimely and abnormal activation of CDK2 is then cytotoxic to cancer cells.

Citation Format: Nandini Sakurikar, Ruth Thompson, Ryan Montano, Alan Eastman. The critical role of CDK2 activation in determining the differential sensitivity of cell lines to Chk1 and Wee1 inhibitors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 943. doi:10.1158/1538-7445.AM2015-943
Abstract 949: An ER-α36 monoclonal antibody exhibits anticancer activity in triple-negative breast cancer cells
Authors: Lin Qingcong , Zhou Junma , Wang Jing , Wang Zonghui , Wang Jun , Chen Feng , Qian Xueming , Shang Xiao , Bao Jun , Wang Zhaoyi , Meng Kun
Published: August 2015

ER-α36 is a novel variant of ER-α, plays an important role in mitogenic estrogen signaling and tamoxifen resistance in both ER-positive and -negative breast cancer. ER-α36 is highly expressed on the plasma membrane of both ER-positive and -negative breast cancer stem/progenitor cells and critical for maintenance of the breast cancer stem/progenitor cells, which make it a promising target for antibody-based breast cancer treatment. In this study, we have screened and identified a candidate of therapeutic antibody named 3C11 that specifically recognizes ER-α36 at its unique C-terminal residues. The antibody 3C11 showed pM affinity to ER-α36 in the BiaCore assay and potent growth inhibitory activity in multiple breast cancer cell lines in vitro. In addition, 3C11 also showed dose-dependent inhibition of tumor growth in a xenograft model formed by a triple-negative breast cancer cell line SUM159 that was generated from a refractory breast cancer. Furthermore, we found that 3C11 was quickly and efficiently internalized into cells, which makes it a potential candidate for development of the antibody-drug conjugate approaches. These results demonstrated that ER-α36 is promising cancer target for development of antibody-based therapeutic approaches.

Citation Format: Qingcong Lin, Junma Zhou, Jing Wang, Zonghui Wang, Jun Wang, Feng Chen, Xueming Qian, Xiao Shang, Jun Bao, Zhaoyi Wang, Kun Meng. An ER-α36 monoclonal antibody exhibits anticancer activity in triple-negative breast cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 949. doi:10.1158/1538-7445.AM2015-949
Abstract 960: Deregulation of the Hippo pathway in soft tissue sarcoma promotes FOXM1 expression and tumorigenesis
Authors: Eisinger T.S. Karin , Mucaj Vera , Biju Kevin , Nakazawa Michael , Gohil Mercy , Cash Timothy , Yoon Sam , Skuli Nicolas , park Kyung Min , Gerecht Sharon , Simon Celeste
Published: August 2015

The genetic aberrations responsible for soft tissue sarcoma formation in adults are largely unknown, and targeted therapies are sorely needed for this complex and heterogeneous family of diseases. Here we report that that the Hippo pathway is deregulated in many soft tissue sarcomas, resulting in elevated expression of the effector molecule YAP. Based on data gathered from human sarcoma patients, we concluded that more than 40% of human sarcomas have lost one or more copies of upstream HIPPO pathway regulators including SAV1, LATS2, and NF2. Loss of these molecules deactivates the HIPPO pathway, permitting uncontrolled proliferation and growth. Expression of active YAP is the direct result of this copy number loss and we have found YAP to be elevated in primary human fibrosarscomas, liposarcomas, and pleomorphic tumors. Pharmacologic inhibition of YAP significantly impaired primary sarcomagenesis in a murine allograft model. Using a novel autochthonous mouse model and mechanistic analyses in human and murine sarcoma cells, we determined that YAP-dependent expression of the transcription factor, FOXM1, is necessary for sarcoma cell proliferation and tumorigenesis. FOXM1 expression is elevated in multiple human soft tissue sarcoma subtypes. Notably, FOXM1 directly interacts with the YAP transcriptional complex via TEAD1, resulting in co-regulation of numerous critical pro-proliferation targets that enhance sarcoma progression. Finally, pharmacologic inhibition of FOXM1 decreases tumor size in vivo, making FOXM1 an attractive therapeutic target for the treatment of sarcomas.

Citation Format: T.S. Karin Eisinger, Vera Mucaj, Kevin Biju, Michael Nakazawa, Mercy Gohil, Timothy Cash, Sam Yoon, Nicolas Skuli, Kyung Min park, Sharon Gerecht, Celeste Simon. Deregulation of the Hippo pathway in soft tissue sarcoma promotes FOXM1 expression and tumorigenesis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 960. doi:10.1158/1538-7445.AM2015-960
Abstract 962: PA2G4 predicts poor prognosis in neuroblastoma patients and promotes neuroblastoma progression by enhancing MYCN protein stability
Authors: Koach Jessica , Liu Bing , Bell Jessica L. , Hüttelmaier Stefan , Liu Tao , Carter Daniel R. , Haber Michelle , Norris Murray D. , Fletcher Jamie , Cheung Belamy B. , Marshall Glenn M.
Published: August 2015

MYCN oncogene amplification is found in one third of primary neuroblastoma at diagnosis, and correlates with poor prognosis. We identified Proliferation-associated protein 2G4 (PA2G4) as a binding partner for MYCN using co-immunoprecipitation and mass spectrometry. The long isoform of PA2G4 (p48) has a known oncogenic function, whereas the short isoform (p42) acts as a tumour suppressor. However, the role of PA2G4 in neuroblastoma and its link with MYCN is currently unknown.

Using a panel of 11 human neuroblastoma cell lines and 477 patient tumour samples, we analysed the expression of PA2G4 by real-time PCR and Western blotting. We found that high expression of PA2G4 was a strong independent clinical predicator of poor survival and positively correlated with MYCN expression. Analysis of pre-cancerous ganglia cells from TH-MYCN neuroblastoma mouse model showed that PA2G4 mRNA was expressed 8-fold higher in ganglia from TH-MYCN transgenic homozygote, compared to wild-type mice.

Chromatin immunoprecipitation showed MYCN binds to PA2G4 promoter to activate its transcription. Surprisingly, suppression of PA2G4 in neuroblastoma cell lines markedly reduced MYCN protein level. Cycloheximide-chase assay confirmed that PA2G4 increased MYCN protein stability, thus creating a positive forward feedback loop which we showed resulted from effects on pERK. Suppression of PA2G4 down-regulated pMDM2 and pAKT, leading to an increase in p53 expression. Furthermore, PA2G4 knockdown promoted retinoid induced neurite formation, reduced cell migration and colony formation. Importantly, the expression of MYCN was required for the effect of PA2G4 on colony formation. A small molecule inhibitor of PA2G4, WS6, significantly decreased neuroblastoma cell growth and PA2G4 and MYCN protein levels.

PA2G4 is a novel MYCN-binding protein which increases MYCN protein stability and acts as an oncogenic co-factor in a forward feedback expression loop with MYCN, to drive MYCN protein levels to high thresholds even in the presence of MYCN amplification.

Citation Format: Jessica Koach, Bing Liu, Jessica L. Bell, Stefan Hüttelmaier, Tao Liu, Daniel R. Carter, Michelle Haber, Murray D. Norris, Jamie Fletcher, Belamy B. Cheung, Glenn M. Marshall. PA2G4 predicts poor prognosis in neuroblastoma patients and promotes neuroblastoma progression by enhancing MYCN protein stability. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 962. doi:10.1158/1538-7445.AM2015-962
Abstract 973: Coordinated regulation of cap-dependent translation and microRNA function by convergent signaling through the PI3K/Akt/mTOR and Jak/Stat/Pim signaling pathways
Authors: Olejniczak Scott H. , La Rocca Gaspare , Radler Megan , Thompson Craig B.
Published: August 2015

Growth and proliferation of tumor cells requires coordinated activation of many cellular processes, including cap-dependent mRNA translation. MicroRNAs oppose cap-dependent translation to set thresholds for expression of target proteins. Emerging data suggest that microRNA function, like cap-dependent translation, is enhanced by activation of cancer-associated signaling due, at least in part, to induction of GW182 protein expression. In the current study, we demonstrate that increased expression of GW182 in normal and transformed hematopoietic cells contributes to enhanced microRNA function by increasing overall capacity for microRNA-mediated target repression. Furthermore, expression of GW182 was found to be regulated post-transcriptionally by the translation initiation complex downstream of convergent signaling through the PI3K/Akt/mTOR and Jak/Stat/Pim signaling pathways, both of which are commonly activated in hematopoietic malignancies. PI3K/Akt/mTOR signaling contributed to GW182 expression primarily by stimulating eIF4E binding to GW182 mRNA, while Jak/Stat/Pim signaling enhanced GW182 expression by additionally increasing eIF4A-dependent unwinding of G-quadraplexes in the 5′ untranslated region (UTR) of GW182 mRNA. Inhibition of either eIF4E-dependent translation initiation by treatment with rapamycin or eIF4A-dependent unwinding of the GW182 5′ UTR by treatment with silvestrol led to decreased GW182 expression and microRNA function. Our data provide a mechanism by which microRNA function is linked to cap-dependent translation, allowing thresholds for expression of microRNA targeted proteins to be maintained despite changes in protein synthesis.

Citation Format: Scott H. Olejniczak, Gaspare La Rocca, Megan Radler, Craig B. Thompson. Coordinated regulation of cap-dependent translation and microRNA function by convergent signaling through the PI3K/Akt/mTOR and Jak/Stat/Pim signaling pathways. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 973. doi:10.1158/1538-7445.AM2015-973
Abstract 998: Induction of non-protective autophagy by radiation in tumor cells: Implications for autophagy inhibition as a therapeutic strategy
Authors: Chakradeo Shweta , Sharma Khushboo , Alhaddad Aisha , Bakhshwin Duaa , Le Ngoc , Harada Hisashi , Yeudall W. Andrew , Torti Suzy , Torti Frank , Gewirtz David
Published: August 2015

Our laboratory has previously described the four functional forms of autophagy, specifically cytoprotective, cytotoxic, cytostatic and nonprotective (Gewirtz DA, Cancer Research 2014). Evidence for the nonprotective form was based on studies where murine 4T1 breast tumor cells failed to be sensitized to ionizing radiation by pharmacological or genetic inhibition of autophagy (Bristol ML, JPET, 2013). To determine whether radiation induces the cytoprotective and nonprotective forms of autophagy in human tumor cells lines of different tissue origin, the influence of autophagy inhibition on radiation sensitivity was studied in human breast, head and neck and non-small cell lung cancer cell lines. In order to examine the potential involvement of p53 in the protective and nonprotective forms of autophagy, the impact of autophagy inhibition on radiation sensitivity was compared in cell lines that were either wild type or mutant/null in p53. While ionizing radiation promoted autophagy in all tumor cell lines studied, autophagy inhibition resulted in radiation sensitivity only in the p53 wild type A549 and H460 NSCLC cells and the HN30 head and neck tumor cells. In contrast, pharmacological inhibition of autophagy and/or genetic silencing of autophagy genes failed to influence sensitivity to radiation in the p53 mutant Hs578t breast tumor cells, the HN6 head and neck tumor cells, and the H358 non-small cell lung cancer cells, indicative of nonprotective autophagy. The apparent requirement for functional p53 in the promotion of cytoprotective autophagy by radiation was confirmed by the observation that radiation induced autophagy was nonprotective in p53 null H1299 cells but was converted to the cytoprotective form with induction of p53. Conversely, whereas p53 wild-type HN30 cells did show sensitization to radiation upon autophagy inhibition HN30 cells in which p53 was knocked down were not sensitized. These observations have implications for efforts to modulate the response of malignancies to radiation (and possibly also to cancer chemotherapeutic drugs) through autophagy inhibition.

Citation Format: Shweta Chakradeo, Khushboo Sharma, Aisha Alhaddad, Duaa Bakhshwin, Ngoc Le, Hisashi Harada, W. Andrew Yeudall, Suzy Torti, Frank Torti, David Gewirtz. Induction of non-protective autophagy by radiation in tumor cells: Implications for autophagy inhibition as a therapeutic strategy. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 998. doi:10.1158/1538-7445.AM2015-998
Abstract 999: Utilization of catastrophic autophagy in ovarian cancer
Authors: Delaney Joe R. , Patel Chandni , Stupack Dwayne G.
Published: August 2015

In ovarian cancer, the dysfunction of apoptotic effectors such as p53 suggests that therapies which act tangential to ‘apoptotic’ pathways may offer alternative avenues to target recalcitrant disease. These pathways include necroptosis, ER stress, and autophagy. Evaluating combinations of agents which impact these pathways, we found that effects of ‘non-toxic’ drugs that induced ER stress and autophagy were potentiated when used with drugs that prevented autophagy resolution. At the cellular level, LC3-II levels were elevated in response to these agents, and predicted efficacy. GRP78 and SQSTM1/p62 were similarly elevated, indicating induction of the ER stress pathway impaired autophagic flux, respectively. The resulting death, via ‘catastrophic autophagy,’ may be an effective way to target traditional-chemotherapy-resistant ovarian cancer.

Citation Format: Joe R. Delaney, Chandni Patel, Dwayne G. Stupack. Utilization of catastrophic autophagy in ovarian cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 999. doi:10.1158/1538-7445.AM2015-999
Abstract CT207: Phase I dose escalation and pharmokinetic study of 14-O-phosphonooxymethyltriptolide
Authors: Greeno Edward , Borazanci Erkut , Gockerman Jon , Korn Ronald , Saluja Ashok , Von Hoff Daniel
Published: August 2015

Introduction: We are conducting a phase I, first-in-human trial of 14-O-phosphonooxymethyltriptolide (Minnelide,) a water-soluble prodrug of triptolide, a diterpene derived from the thunder god vine (tripterygium wilfordii). Triptolide is a potent inhibitor of heat shock protein 70 (HSP70) and pancreatic ductal adenocarcinoma over-expresses HSP70 as a protective mechanism. We have previously shown Minnelide to be effective and well tolerated in preclinical models of pancreatic carcinoma.

Methods: The study uses a 3+3 dose escalation scheme, enrolling subjects with gastrointestinal malignancies refractory to standard therapies. The drug is administered as a daily, brief IV infusion for 21 days out of a 28 day cycle. The primary endpoint is toxicity, with secondary endpoints of pharmokinetics and response.

Results: To date we have enrolled 27 subjects (17 pancreas, 7 colorectal, 3 other GI) at doses from 0.16 to 0.8 mg/m2, with 24 evaluable for toxicity. The therapy has been generally well tolerated with the only common toxicity being hematologic, but one patient experienced reversible cerebellar dysfunction at the highest dose. Pharmokinetics (n = 21) indicate rapid conversion of Minnelide to triptolide, with all Minnelide cleared within 30 minutes and peak triptolide levels achieved within 5 minutes of completion of infusion. Triptolide was rapidly cleared with a half-life of less than 30 minutes, and complete clearance by 6 hours, except in the patient with cerebellar toxicity who demonstrated delayed clearance of the drug. All subjects, except those in the lowest dose cohort, have had a reduction in HSP70 levels. The 9 patients in the first 3 dose cohorts all progressed by the end of cycle two. Tumor response by PET after cycle 1 (n = 19), shows a partial metabolic response in 36%, and stable metabolic disease in 52%. Response after 2 cycles by RECIST criteria (n = 10) shows a 10% PR (gastric) and 60% SD (5 pancreas, 1 rectal) rate with disease control for up to 6 months. 5 patients remain on study, with ongoing enrollment planned.

Conclusions: We have seen promising evidence of significant clinical activity in this group of heavily pretreated patients with refractory GI malignancies. The toxicity profile and optimal dosing of Minnelide are being defined.

Citation Format: Edward Greeno, Erkut Borazanci, Jon Gockerman, Ronald Korn, Ashok Saluja, Daniel Von Hoff. Phase I dose escalation and pharmokinetic study of 14-O-phosphonooxymethyltriptolide. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT207. doi:10.1158/1538-7445.AM2015-CT207
Abstract CT211: Biomarker search using gene expression databases in a phase III controlled clinical trial of postoperative adjuvant chemotherapy for stage III colon cancer (ACTS-CC): correlation between clinicopathological factors and gene expression level
Authors: Uetake Hiroyuki , Ishikawa Toshiaki , Ishiguro Megimi , Matsui Shigeyuki
Published: August 2015

Background: The ACTS-CC trial is a randomized, controlled phase III study designed to validate the noninferiority of S-1 to UFT/leucovorin as adjuvant chemotherapy for stage III colon cancer and rectosigmoid cancer. A prospective biomarker search was performed as an auxiliary study of the ACTS-CC trial, using formalin-fixed, paraffin-embedded (FFPE) specimens obtained from 892 patients. The gene expression levels of 5-FU metabolizing enzymes and folate metabolizing enzymes and alterations of genome-wide copy numbers in tumor have been reported (2012, 2013 and 2014 Annual Meetings of AACR). In the present study, we performed correlation analyses of clinicopathological feature and gene expression level.

Methods: Blocks of resected tumor specimens for this biomarker study were obtained after receiving informed consent from 892 of 1535 patients enrolled between April 2009 and January 2010. Macro-dissections were manually performed to extract total RNA and genomic DNA from 10-μm-thick FFPE specimens of colon cancer. Gene expression levels of 11 enzymes (TS, DPD, TP, OPRT, FPGS, GGH, DHFR, MTHFR, MTHFD, FOLRA, GART) related to 5-FU and folic acid metabolism were studied according to the Danenberg Tumor ProfileTM method (Shirota, Y. JCO 2001).

Results: Gene expression levels were successfully estimated in 521-808 samples (84.0-90.0%, median 89.4%). Among 11 genes, GGH most strongly correlated with tumor locations: expression level of GGH in the distal colon was 1.8 times higher than those in the proximal colon. Gene expressions of DPD and GGH were significantly influenced by differentiation of tumor. DPD and GGH mRNA levels in poorly differentiated tumors were 2.0 or 2.5 times higher than those in well differentiated tumors, respectively. Likewise, TS most strongly correlated with tumor depth: expression level in T1 or T2 tumor was 1.3 times higher than those in T4 tumor.

Conclusions: Location, differentiation and depth of the tumor correlated with each gene expressions. Our findings will facilitate understanding the characteristics of colon cancer. Further investigation on gene expressions including genome-wide copy number analysis may contribute to the exploration of valid biomarkers.

Citation Format: Hiroyuki Uetake, Toshiaki Ishikawa, Megimi Ishiguro, Shigeyuki Matsui. Biomarker search using gene expression databases in a phase III controlled clinical trial of postoperative adjuvant chemotherapy for stage III colon cancer (ACTS-CC): correlation between clinicopathological factors and gene expression level. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT211. doi:10.1158/1538-7445.AM2015-CT211
Abstract LB-035: Hepatitis C virus NS3/4A hijacks the host B-cell receptor signaling pathway
Authors: Dai Bojie , Landon Ari , Houng Simone , Gartenhaus Ronald B.
Published: August 2015

B-cell receptor (BCR) signaling is critical for the development of normal B-cells and B-cell lymphoma. Increasing epidemiological evidence indicates an association between chronic hepatitis C virus (HCV) infection and B-cell lymphoma, however, the mechanisms by which HCV causes B-cell lymphoproliferative disorder are still unclear. Herein, we demonstrate the expression of HCV viral proteins in B-cells of HCV-infected patients and show that HCV up-regulates BCR signaling in human primary B-cells. HCV nonstructural protein NS3/4A interacts with CHK2 and down-regulates its activity, modulating HuR posttranscriptional regulation of a network of target mRNAs associated with B-cell lymphoproliferative disorders. Strikingly, the BCR signaling pathway was found to have the largest number of transcripts with increased association with HuR and up-regulated by NS3/4A. Our study reveals a previously unidentified role of NS3/4A in regulation of host BCR signaling during HCV infection, lending further insight into the molecular mechanisms underlying HCV-associated B-cell lymphoproliferative disorders.

Citation Format: Bojie Dai, Ari Landon, Simone Houng, Ronald B. Gartenhaus. Hepatitis C virus NS3/4A hijacks the host B-cell receptor signaling pathway. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-035. doi:10.1158/1538-7445.AM2015-LB-035
Abstract LB-038: Caspase-mediated iASPP cleavage inhibits NF-kB
Authors: Hu Ying , Ge Wenjie , Wang Xinwen , Lu Xin
Published: August 2015

Constitutive activation of the transcription factor nuclear factor-kB (NF-κB) plays an important role in oncogenesis and drug resistance of several types of human cancers. Inhibiting NF-κB pathways is therefore emerging as a promising approach to treat cancer. iASPP was first reported as an NF-κB binding partner and inhibitor in a yeast-two-hybrid system. However, it remains unknown how this activity is regulated in cells. For the first time, we show that the activity of iASPP is regulated by caspase-dependent cleavage at cellular level. iASPP was cleaved by caspases at a very early stage of treatment. Interestingly, in contrast to full-length iASPP that is predominantly cytosolic, the iASPP fragment accumulates in the nucleus. Cleaved iASPP shows increased interaction with NF-kB, which correlates with reduced activity of κB reporter. Overexpression iASPP fragment results in increased apoptosis. It also sensitizes cancer cells’ response to paclitaxe. Thus, this study reveals a novel mechanism by which caspase cleavage relocates iASPP from cytoplasm to the nuclear compartment and to pro-apoptotic machinery by binding and subsequent inhibiting NF-κB. This study also provides insights into new strategies to conquer drug resistance of NF-kB constitutive activated malignancies.

Citation Format: Ying Hu, Wenjie Ge, Xinwen Wang, Xin Lu. Caspase-mediated iASPP cleavage inhibits NF-kB. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-038. doi:10.1158/1538-7445.AM2015-LB-038
Abstract LB-039: 1,25 dihydroxyvitamin D3 and cisplatin combination modulate p73 in bladder cancer
Authors: Bunch Brittany L. , Woloszynska-Read Anna , Trump Donald L. , Johnson Candace S.
Published: August 2015

Cisplatin-based combination chemotherapy is the standard approach to therapy of advanced bladder cancer. While there is a substantial initial response rate and occasional complete response, long term control is not common. There is a need to develop new therapeutic approaches to bladder cancer. 1,25 dihydroxyvitamin D3 (1,25D3), the active metabolite of vitamin D, enhances the anti-tumor effects of cisplatin in preclinical bladder cancer models. We evaluated the mechanism of 1,25D3 potentiation of cisplatin cytotoxicity through in vitro studies in bladder cancer cell lines. Our studies suggest that enhanced cytotoxicity is mediated through modulation of p73. The ratio of the pro-apoptotic TAp73 isoform to the anti-apoptotic ΔNp73 isoform is important in determining cellular response to cisplatin. Our studies demonstrate that pretreatment with 1,25D3 (0.5 uM) for 24 hrs followed by cisplatin (0.75 ug/ml) for 48 hrs increases the ratio of TA/ΔNp73 mRNA transcripts 2-fold in the T24 bladder cancer cell line, and increases TAp73's transcriptional target, BAX approximately 3-fold compared to cisplatin alone. Protein levels of p73 and BAX, are also increased with 1,25D3 pretreatment followed by cisplatin in T24 cells as determined by western blot. Using a TransAm p53 binding assay after p53 immunodepletion, cisplatin treatment was found to decrease TAp73 functional ability to bind DNA by approximately half, although this has not yet been determined to be statistically significant. 1,25D3 pretreatment followed by cisplatin prevents the decrease in TAp73 DNA binding found after cisplatin alone. These data suggest an increase in TAp73 pro-apoptotic functional abilities resulting from 1,25D3 pretreatment followed by cisplatin in T24 cells. These findings suggest that 1,25D3 may have potential to be used in combination with cisplatin to increase the apoptotic response. Further studies are being performed to determine the requirement of TAp73 in 1,25D3 potentiation of cisplatin cytotoxicity by using T24 cells transfected with TAp73 shRNA in assays previously used to determine synergism, ie. MTT, clonogenic, and apoptosis assays. Supported by NCI grants CA067267 and CA016056.

Citation Format: Brittany L. Bunch, Anna Woloszynska-Read, Donald L. Trump, Candace S. Johnson. 1,25 dihydroxyvitamin D3 and cisplatin combination modulate p73 in bladder cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-039. doi:10.1158/1538-7445.AM2015-LB-039
Abstract LB-046: Evaluation of known low-penetrance thyroid cancer risk alleles in a Hispanic population from South America
Authors: Estrada-Flórez Ana , Bohórquez-Lozano Mabel E. , Prieto-Sánchez Rodrigo , Mateus Gilbert F. , Rios Alejandro , Vélez Hoyos Alejandro , Duque Carlos S. , Ledda Mirko A. , Erazo Maria J. , Bolaños Fernando , Panqueba Cesar , Echeverry de Polanco María Magdalena , Carvajal-Carmona Luis G.
Published: August 2015

TC is one of the most common malignancy that shows familial inheritance with ∼8 fold increase in the risk of developing TC in first-degree relatives affected by this disease. Recent genome-wide association studies (GWAS) aimed at characterizing the risk loci for TC have identified five single nucleotide polymorphisms (rs966423, rs2439302, rs965513, rs116909374 and rs944289) associated with increased risk for TC. However, effect of these polymorphisms have bot been studied in any Hispanic population. Therefore, the aim of this study was to analyze the above-mentioned SNPs in 235 TC patients and 588 healthy controls from Central Colombia using KASP genotyping system. Genotype frequencies, Hardy Weinberg equilibrium (HWE) and association testing was carried out using Plink. The cumulative genetic risk was assessed using unweighted and weighted approaches. Significant associations between thyroid cancer risk and rs965513A (OR = 1.503, 95% CI: 1.203-1.886, P = 0.00038) and rs944289T (OR = 1.372, 95% CI: 1.095-1.699, P = 0.00488) was observed in our study. Consistent, yet not -significant associations were observed between disease risk and rs2439302T (OR = 1.177, 95% CI: 0.931-1.477, P = 0.1666) and rs116909374A (OR = 1.626, 95% CI: 0.799-3.766, P = 0.2443). For rs966423G, significant departure from HWE was observed therefore this SNP was excluded from further analysis. The combined analyses of rs2439302, rs965513, rs116909374 and rs944289 showed consistent associations between the number of disease alleles and cancer risk. Having three risk alleles increased disease risk by two-fold (OR = 2.09, 95% CI:1.46 - 3.02),while carrying five risk alleles was associated with nearly 4-fold increase in the disease risk (OR = 3.84, 95% CI:1.47 - 10.06). To our knowledge, this was the first study that assessed TC risk associated with known polymorphisms in the Hispanic population and suggest that these variants could be used in future risk prediction profiling studies in these populations.

Citation Format: Ana Estrada-Flórez, Mabel E. Bohórquez-Lozano, Rodrigo Prieto-Sánchez, Gilbert F. Mateus, Alejandro Rios, Alejandro Vélez Hoyos, Carlos S. Duque, Mirko A. Ledda, Maria J. Erazo, Fernando Bolaños, Cesar Panqueba, María Magdalena Echeverry de Polanco, Luis G. Carvajal-Carmona. Evaluation of known low-penetrance thyroid cancer risk alleles in a Hispanic population from South America. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-046. doi:10.1158/1538-7445.AM2015-LB-046
Abstract LB-075: The histone demethylase JMJD1A is essential to prostate cancer cells through regulation of c-Myc expression
Authors: Fan Lingling , Peng Guihong , Sahgal Natasha , Fazli Ladan , Gleave Martin , Zhang Yuji , Hussain Arif , Qi Jianfei
Published: August 2015

Histone demethylase JMJD1A controls gene expression by epigenetic regulation of H3K9 methylation marks. To investigate role of JMJD1A in the development and progression of prostate cancer, we knock down JMJD1A in prostate cancer cells and examine its effect on gene expression and cancer cell biology. We find that silencing of JMJD1A results in the lethality of prostate cancer cells concomitant with inhibition of cell proliferation, induction of apoptosis and cell cycle arrest. Profiling array analyses reveal c-Myc as one of the top transcriptional networks altered upon the JMJD1A inhibition. The gene ontology pathway analyses show that the primary functions of c-Myc targets regulated by JMJD1A are related to cell cycle, cell proliferation and cell survival. Mechanistically, JMJD1A promotes the recruitment of AR and induces demethylation at the c-Myc gene enhancer, thereby increasing the AR-dependent transcription of c-Myc mRNA. In a parallel pathway, JMJD1A binds to E3 ubiquitin ligase HUWE1, attenuates the HUWE1-induced degradation of c-Myc, and thus increases the c-Myc protein level. Together, JMJD1A controls the expression of c-Myc at transcriptional and post-translational levels. Re-expression of c-Myc in the JMJD1A-knockdown cells partly recues the growth of prostate cancer cells in vitro and in vivo. The protein level of c-Myc is positively correlated with that of JMJD1A in a subset of human prostate cancer specimens. Collectively, our findings identify a critical role of JMJD1A for the viability of prostate cancer cells through regulation of c-Myc expression.

Note: This abstract was not presented at the meeting.

Citation Format: Lingling Fan, Guihong Peng, Natasha Sahgal, Ladan Fazli, Martin Gleave, Yuji Zhang, Arif Hussain, Jianfei Qi. The histone demethylase JMJD1A is essential to prostate cancer cells through regulation of c-Myc expression. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-075. doi:10.1158/1538-7445.AM2015-LB-075