bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 818: Chronic oxidative stress induces conversion of estrogen-dependent non-aggressive breast cancer cells into estrogen-independent aggressive phenotype
Authors: Mahalingaiah Prathap Kumar S. , Ponnusamy Logeswari , Singh Kamaleshwar P.
Published: August 2015

We have recently reported increased growth and tumorigenic potential of estrogen receptor (ER) positive breast cancer cells with chronic exposure to oxidative stress. In this study, we evaluated mechanistic basis for chronic oxidative stress-induced aggressiveness in ER positive MCF-7 breast cancer cells. Loss of estrogen dependency is known to be associated with acquisition of aggressive form in breast cancer cells. Therefore, the objective of this study was to evaluate changes in estrogen response in ER-positive breast cancer cells exposed to chronic oxidative stress. MCF-7 cells were exposed to hydrogen peroxide (H2O2)-induced oxidative stress for chronic period (6 months). Using these cells, growth response to 17-β estradiol was evaluated by MTT assay and cell cycle analysis. Surprisingly, in response to 17-β estradiol treatment, there was no significant growth stimulation in cells exposed to chronic oxidative stress. Cell cycle analysis by flow cytometry further confirmed the cell growth data. Quantitative RT-PCR analysis also revealed significant down regulation of ER-α in chronically exposed breast cancer cells. To understand the role of epigenetic mechanism, the expression of epigenetic regulatory genes were determined at both transcript and protein level. In addition, the levels of histone modifications were also evaluated by Western blot analysis. Changes in both the expression of epigenetic regulatory genes (DNMT1, DNMT3b, HDAC1, MBD4, and HAT1) and the levels of histone modifications (H3K27 tri-methylation and H3K18 acetylation) were observed in MCF-7 cells chronically exposed to H2O2. Treatment with DNA de-methylating agent (5-aza-2′-deoxycytidine) restored the ER-α expression level, estrogen-induced growth and oxidative stress induced histone modifications. To summarize, the findings of this study suggest that chronic exposure to oxidative stress can convert estrogen-dependent non-aggressive breast cancer cells into estrogen-independent aggressive form potentially by epigenetic mechanism.

Citation Format: Prathap Kumar S. Mahalingaiah, Logeswari Ponnusamy, Kamaleshwar P. Singh. Chronic oxidative stress induces conversion of estrogen-dependent non-aggressive breast cancer cells into estrogen-independent aggressive phenotype. [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 818. doi:10.1158/1538-7445.AM2015-818
Abstract 825: Molecular mechanisms of regulation of cytochrome P4501A enzymes by 3-methylcholanthrene (MC) in mice in vivo
Authors: Moorthy Bhagavatula , Weiwu Jiang , Wang Lihua , Chu Chun , Kondraganti Sudha R. , Maturu Paramahamsa
Published: August 2015

3-Methylcholanthrene (MC) is one of the most potent polycyclic aromatic hydrocarbons (PAHs) present in cigarette smoke, diesel exhausts, and charcoal broiled meats, etc. Cytochrome P450 (CYP)1A enzymes play key roles in the activation of PAHs to carcinogenic metabolites. We previously showed persistent induction of CYP1A enzymes by MC in vivo. In this study, we tested the hypothesis that MC elicits persistent induction of CYP1A1 in vivo by sustained transcriptional activation of the CYP1A1 promoter. Thirty two C57B6 (WT) mice were divided into two groups. Group I was treated with vehicle corn oil (CO) (8ml/kg) and group II was treated with a single dose of MC (100 μmol/kg), i.p. Four animals from each group were sacrificed at 6, 12, 24, and 48 h after MC withdrawal. The mRNA levels, protein content and enzyme activities of CYP1A1 were determined by real-time PCR, Western blotting, and fluorimetry, respectively at different time points. In addition, the binding of MC-AHR-AHR nuclear translocator (ARNT) to the AHREs on the CYP1A1 promoter region were determined by chromatin immunoprecipitation (ChIP) assay. The translocation of AHR was also analyzed by immunofluorescence. The ChIP experiments indicated that transcriptional activation of CYP1A1 was most pronounced at 6 h, followed by 12 h, but declined at later time points. On the other hand, the expression of CYP1A1 at the mRNA, protein and enzyme levels persisted for up to 48 h both in lung and liver tissues. These results suggest that transcriptional activation of CYP1A1 at 6-12 h is sufficient to result in sustained induction of CYP1A mRNA and protein expression for up to 48 h. Isolation of the immunoprecipitated promoter fragment (containing the xenobiotic response elements), which binds to the MC-AHR complex, followed by 32P-postlabeling revealed the formation of MC-DNA adducts, suggesting that DNA adducts are sequence-specific and target the CYP1A1 promoter. Our results suggest that DNA adducts might play a role in regulation of CYP1A1 by MC, a phenomenon that may be of relevance to PAH-mediated carcinogenesis.

Citation Format: Bhagavatula Moorthy, Jiang Weiwu, Lihua Wang, Chun Chu, Sudha R. Kondraganti, Paramahamsa Maturu. Molecular mechanisms of regulation of cytochrome P4501A enzymes by 3-methylcholanthrene (MC) in mice in vivo. [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 825. doi:10.1158/1538-7445.AM2015-825
Abstract 83: Comparison of surface-directed and classic androgen receptor antagonists
Authors: Suh Ji Ho , Chattopadhyay Arundhati , Sieglaff Douglas H. , Storer Cheryl L. , Cox Marc B. , Webb Paul
Published: August 2015

Background: The androgen receptor (AR) surface-directed antagonist MJC13 inhibits AR function and proliferation of prostate cancer (PC) cells and these effects are related to arrest of an AR/chaperone complex in the cytoplasm. Here, we compared activities of MJC13 and the classic AR antagonist flutamide.

Method and Results: MJC13 and flutamide inhibit all dihydrotestosterone (DHT)-dependent genes in LNCaP PC cells and both compounds are equally effective. Control ChIP assays confirm that MJC13 inhibits AR binding to the prostate specific antigen (PSA) promoter more strongly than flutamide, consistent with different mechanisms of action. Examination of efficacy of MJC13 in conditions that reflect aspects of castrate resistant prostate cancer (CRPC) reveals that it inhibits a flutamide-dependent AR mutant (ART877A), but displays greatly restricted gene-specific activity in 22Rv1 cells that express a constitutively active truncated AR and is inactive against glucocorticoid receptor (GR), which can co-opt androgen-dependent signaling networks in CRPC. While flutamide inhibits AR interactions with the coactivator SRC2, it does not affect β-catenin binding. In contrast, MJC13 inhibits AR interactions with both coregulators and, unlike flutamide, strongly inhibits amplification of AR activity obtained with SRC2 and β-catenin. MJC13 also preferentially inhibits β-catenin-enhanced cell division in LNCaP cells relative to flutamide.

Conclusion: Our findings suggest that a surface-directed antagonist can block AR activity in some conditions in which a classic antagonist fails and may display utility in some forms of CRPC.

Citation Format: Ji Ho Suh, Arundhati Chattopadhyay, Douglas H. Sieglaff, Cheryl L. Storer, Marc B. Cox, Paul Webb. Comparison of surface-directed and classic androgen receptor antagonists. [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 83. doi:10.1158/1538-7445.AM2015-83
Abstract 85: CCAAT/enhancer binding protein beta facilitates castrate-resistant prostate cancer cell growth and sensitivity to mTOR inhibitors
Authors: Barakat David J. , Zhang Jing , Friedman Alan D. , Denmeade Samuel R. , Paz-Priel Ido
Published: August 2015

Adaptive changes that frequently occur in castrate-resistant prostate cancer (CRPC) cells are genomic mutations which enhance the activity of the PI3K-mTOR signaling pathway. Although there have been several promising clinical trials for the treatment of CRPC utilizing inhibitors of mTOR, these efforts failed to show significant improvement of patient outcomes. Thus, identifying potential mechanisms of resistance to these agents could improve their therapeutic efficacy. CCAAT/enhancer binding protein beta (C/EBPβ) is a broadly expressed transcription factor, with three isoforms that are differentially translated by mTOR activity. T reatment of cells with mTOR inhibitors increases the translation of the larger C/EBPβ LAP isoforms and decreases the truncated LIP isoform. The function of C/EBPβ LAP has been previously associated with survival and cellular senescence, while the LIP isoform facilitates cell cycle progression. Our central hypothesis was that the differential translation of LAP and LIP C/EBPβ isoforms was essential for the survival of CRPC cells treated with mTOR inhibitors. We found that treatment of PC3 cells with mTOR inhibitors unexpectedly increased the protein levels of all three C/EBPβ isoforms, while androgen-sensitive LNCaP cells largely showed decreased C/EBPβ protein levels. However, the PI3K inhibitor LY294002, decreased the LIP isoform of C/EBPβ without affecting LAP expression in LNCaP and PC3 cells. C/EBPβ gene expression decreased in both LNCaP and PC3 cells in response to treatment with mTOR inhibitors. We next evaluated whether C/EBPβ facilitated cell survival during mTOR inhibition. We found that PC3 cells deficient in C/EBPβ, via shRNA knockdown or TALEN gene editing, were less sensitive to the mTORC1/2 inhibitor, INK128, as assessed by a significant increase in IC50 value determined by the WST-1 assay. Further, suppression of C/EBPβ through shRNA KD or TALEN targeting dramatically decreased the rate of PC3 cell growth, clonogenic potential and induced a senescent phenotype. Intriguingly, loss of C/EBPβ in LNCaP cells increased clonogenic potential. Collectively, these data suggest that C/EBPβ has a differential role for cell growth in androgen-sensitive versus castrate-resistant prostate cancer and that C/EBPβ levels inversely correlate with mTOR inhibitor resistance.

Citation Format: David J. Barakat, Jing Zhang, Alan D. Friedman, Samuel R. Denmeade, Ido Paz-Priel. CCAAT/enhancer binding protein beta facilitates castrate-resistant prostate cancer cell growth and sensitivity to mTOR 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 85. doi:10.1158/1538-7445.AM2015-85
Abstract 855: History of oral contraceptive use in breast cancer patients and risk for early breast cancer events
Authors: Huzell Louise , Persson Mia , Simonsson Maria , Markkula Andrea , Ingvar Christian , Rose Carsten , Jernström Helena C.
Published: August 2015

Whether previous oral contraceptive (OC) use impacts on prognosis women who subsequently develops breast cancer is unclear. The aim was to study history of OC use in relation to breast cancer events in a prospective population-based cohort.

Between 2002 and 2011, primary breast cancer patients without preoperative treatment were enrolled in Lund, Sweden and followed until December 2012. Tumor characteristics, clinical data, and date of death were obtained from pathology reports, patient charts, and population registries. History of OC use was obtained from preoperative questionnaires.

Among the 948 patients with invasive cancer and no metastasis detected on the postoperative screen, 74% had ever used OCs. Patients were followed for up to nine years and 100 breast cancer events were recorded. Ever OC users had significantly smaller tumors than patients who never used OCs (Ptrend = 0.013). However, there was a significantly higher frequency of grade III tumors in patients with OCs use before age 20 (Ptrend = 0.013), compared to patients with later start or never use. Ever OC use was not associated with prognosis, irrespective of duration. However, any OC use before age 20 was associated with a 3-fold increased risk for breast cancer events in patients younger than 50 years at diagnosis (adjusted HR 3.26: 95% CI 1.06-10.01) adjusted for age, tumor size, axillary lymph node involvement, histological grade, estrogen receptor status, and body mass index, but not in patients 50 years or older at diagnosis (Pinteraction = 0.009). In conclusion, these findings warrant confirmation in an independent cohort. If confirmed, history of OC use may yield prognostic information in addition to currently used criteria.

Citation Format: Louise Huzell, Mia Persson, Maria Simonsson, Andrea Markkula, Christian Ingvar, Carsten Rose, Helena C. Jernström. History of oral contraceptive use in breast cancer patients and risk for early breast cancer events. [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 855. doi:10.1158/1538-7445.AM2015-855
Abstract 86: Live-cell profiling of inhibitors targeting the N/C interaction within the androgen receptor
Authors: Yurlova Larisa , Buchfellner Andrea , Gregor Jacqueline , Romer Tina , Hickson Ian
Published: August 2015

Androgen receptor (AR) is an important target for drug therapies combating prostate cancer. However, various acquired mutations within the AR sequence often render resistance to these treatments. Since intramolecular interactions between the N- and C-terminus of AR are implicated in AR activation, it is essential to understand how AR inhibitors alter the N/C interaction within the AR, both for the wt receptor and for its mutant forms.

In this study we applied our recently developed Fluorescent-Two Hybrid (F2H) assay for live-cell analysis of AR N/C interactions. F2H enables real-time visualization and quantitative analysis of interactions between GFP- and RFP- tagged proteins in live mammalian cells. The F2H principle employs a tethering strategy: a GFP-tagged protein is enriched at the protein interaction platform of engineered F2H-BHK cells and serves as bait, whereas an RFP-tagged protein serves as a prey. Here, AR-LBD (wt or mut) was fused to GFP, AR-TAD was fused to RFP, both constructs were co-transfected into the F2H cells, treated with modulatory compounds and the LBD/TAD interactions were evaluated by fluorescence microscopy.

With F2H we analyzed the effects of DHT +/- flutamide, abiraterone, bicalutamide and enzalutamide in live cells. As expected, we observed striking differences in the effects of these treatments on the interactions between the AR-TAD and wt or mut AR-LBD (wt vs W741L, F876L, T877A, F876L-T877A). Further, we compared the effects of the selected compounds on AR-TAD and AR-LBD (wt vs mut) interactions in dose-response F2H assays. We also compared kinetics of these inhibitors with real-time imaging in F2H cells. We further validated our F2H findings with cell-lysate-ELISA on GFP-multiTrap plates. The acquired results correlate well with the published proliferation/reporter-assay data and clarify the role of the intramolecular AR N/C interactions in downstream effects.

Taken together, our results demonstrate that the fully reversible cellular F2H assay enables side-by-side profiling of new inhibitors and activators of protein-protein interactions with respect to their intracellular activity, cell penetration and kinetics.

Citation Format: Larisa Yurlova, Andrea Buchfellner, Jacqueline Gregor, Tina Romer, Ian Hickson. Live-cell profiling of inhibitors targeting the N/C interaction within the androgen receptor. [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 86. doi:10.1158/1538-7445.AM2015-86
Abstract 879: Menopausal hormone therapy and risk of primary liver cancer in the UK Clinical Practice Research Datalink
Authors: McGlynn Katherine A. , Hagberg Katrina , Chen Jie , Jick Susan , Sahasrabuddhe Vikrant V.
Published: August 2015

Background: The incidence of primary liver cancer (PLC) is three to four times higher among males than females in almost all countries. The discrepancy in rates is particularly notable prior to menopause, suggesting that estrogen exposure may be associated with lower risk. The relationship of menopausal hormone therapy (MHT) use to risk of PLC among women, however, has not been extensively examined.

Methods: We conducted a nested case-control study among women in the U.K.'s Clinical Practice Research Datalink (CPRD). Women diagnosed with primary liver cancer (n = 339) between 1988 and 2011 were matched to controls at a 4:1 ratio on age, index year, general practice and length of history in the CPRD. Odds ratios (OR) and 95% confidence intervals (95%CI) for associations of MHT with PLC were estimated using conditional logistic regression. All models were conditioned on the matching factors and adjusted for body mass index, HBV, HCV, smoking, alcohol-related disorders, diabetes, rare metabolic disorders, history of a bilateral oophorectomy, and use of certain medications, including paracetamol, aspirin, anti-diabetes therapies, and statins.

Results: Use of MHT for 6 months or longer was associated with a significantly lower risk of PLC (OR = 0.60, 95%CI = 0.39-0.92). Examination by length of MHT use found that use between 6-30 months was associated with significantly reduced risk (OR = 0.47, 95%CI = 0.24-0.91), while use greater than 30 months did not attain statistical significance (OR = 0.68, 95%CI = 0.41-1.13). When MHT was stratified by formulation (estrogen-only vs estrogen/progesterone), estrogen-only use was associated with significantly lower risk of PLC (OR = 0.51, 95%CI = 0.26-0.97) while estrogen/progesterone use did not attain statistical significance (OR = 0.65, 95%CI = 0.39-1.08).

Conclusion: MHT use, in particular estrogen-only MHT use, may be associated with lower risk of PLC. These findings are consistent with rodent models which have reported suppression of both fatty liver and hepatocarcinogenesis with administration of estrogen. As the association in the current study was apparent among users of 6-30 months, even short-term use of estrogen-only MHT may reduce risk.

Citation Format: Katherine A. McGlynn, Katrina Hagberg, Jie Chen, Susan Jick, Vikrant V. Sahasrabuddhe. Menopausal hormone therapy and risk of primary liver cancer in the UK Clinical Practice Research Datalink. [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 879. doi:10.1158/1538-7445.AM2015-879
Abstract 884: Associations of intakes of magnesium and calcium and survival among women with breast cancer: Results from Western New York Exposures and Breast Cancer (WEB) Study
Authors: Tao Menghua , Dai Qi , Millen Amy E. , Nie Jing , Edge Stephen B. , Trevisan Maurizio , Shields Peter G. , Freudenheim Jo
Published: August 2015

Background: Magnesium (Mg) and calcium (Ca) antagonizes each other in (re)absorption, cell cycle regulation, inflammation, and many other physiologic activities. However, few studies have investigated the association between Mg and Ca intakes and breast cancer survival, and the interaction between Ca and Mg intake.

Method: In a cohort of 1,170 women with primary, incident, and histologically confirmed breast cancer from Western New York State, we examined the relationship between intakes of these two minerals and survival. Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI).

Results: Mean follow-up time was 87.4 months after breast cancer diagnosis; there were 170 deaths identified. After adjustment for known prognostic factors, and intakes of energy, total vitamin D and total Ca, higher dietary intake of Mg was inversely associated with risk of all-cause mortality (HR = 0.50, 95% CI, 0.28-0.90 for highest vs. lowest tertile; p trend = 0.02). Likewise, a marginal association was found for total Mg intake from foods and supplements combined (HR = 0.58, 95% CI, 0.31-1.08; p trend = 0.09). The inverse association of higher total Mg intake with all-cause mortality was primarily presented among postmenopausal women and was stronger among women who had a high Ca:Mg intake ratio (>2.59). There were no clear associations for prognosis with intake of Ca.

Conclusion: We found that Mg intake alone may improve overall survival following breast cancer, and the association may be stronger among those with high Ca:Mg intake ratio.

Citation Format: Menghua Tao, Qi Dai, Amy E. Millen, Jing Nie, Stephen B. Edge, Maurizio Trevisan, Peter G. Shields, Jo Freudenheim. Associations of intakes of magnesium and calcium and survival among women with breast cancer: Results from Western New York Exposures and Breast Cancer (WEB) Study. [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 884. doi:10.1158/1538-7445.AM2015-884
Abstract 90: K63-linked JARID1B ubiquitination by TRAF6 contributes to aberrant elevation of JARID1B in prostate cancer
Authors: Lu Wenfu , Liu Shenji , Li Bo , Xie Yingqiu , Adhiambo Christine , Yang Qing , Ballard Billy R. , Nakayama Keiichi I. , Matusik Robert J. , Chen Zhenbang
Published: August 2015

Aberrant elevation of JARID1B and histone H3 Lys4 trimethylations (H3K4me3) is frequently observed in many diseases including prostate cancer (PCa), yet the mechanisms on the regulations of JARID1B and H3K4me3 through epigenetic modifications still remain poorly understood. In this study we performed immunohistochemistry staining, immunofluorescence imaging, immunoprecipitation, shRNA and Western blotting analysis in mouse embryonic fibroblasts (MEFs), mouse models, and cultured human prostate cancer cells. As a result, we discovered that SKP2 modulates JARID1B and H3K4me3 levels in vitro in PTEN null prostate cancer cells and in vivo in Pten/Trp53 mouse models. We demonstrated that levels of SKP2, JARID1B and H3K4me3 are strikingly elevated in vitro and in vivo when both PTEN and P53 are inactivated. Importantly, SKP2 inactivation resulted in a reduction of cell growth, cell migration and malignant transformation of Pten/Trp53 double null MEFs, and further restrained prostate tumorigenesis of Pten/Trp53 mutant mice. Mechanistically, JARID1B is ubiquitinated by E3 ligase TRAF6 through the K63-linkage in prostate cancer cells. Interestingly, SKP2 contributes to JARID1B ubiquitination machinery as a non-E3 ligase regulator by decreasing TRAF6-mediated ubiquitination of JARID1B. SKP2 deficiency resulted in an increase of JARID1B ubiquitination and in turn a reduction of H3K4me3, and induced senescence through JARID1B accumulation in nucleoli of PCa cells and prostate tumors of mice. Furthermore, we showed that the aberrant levels of SKP2, JARID1B, and H3K4me3 are associated with malignant features of castration-resistant prostate cancer (CRPC) in mice. Overall, our findings reveal a novel network of SKP2- JARID1B, and targeting SKP2 and JARID1B may be a potential strategy for PCa control.

Citation Format: Wenfu Lu, Shenji Liu, Bo Li, Yingqiu Xie, Christine Adhiambo, Qing Yang, Billy R. Ballard, Keiichi I. Nakayama, Robert J. Matusik, Zhenbang Chen. K63-linked JARID1B ubiquitination by TRAF6 contributes to aberrant elevation of JARID1B in prostate 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 90. doi:10.1158/1538-7445.AM2015-90
Abstract 908: Impact of microbial metabolites and resveratrol in prostate cancer progression and clearance
Authors: Stokes James , Mishra Manoj K.
Published: August 2015

Short-chain fatty acids (SCFAs) are the chemical by-products of microbial fermentation. Resistant carbohydrates, some starches, and foods generally rich in fiber are used as substrates for this process. SCFAs are known to activate key cellular receptors such as GPR43/FFA2, which mediate programmed cell death in different cancer cells. Resveratrol (RES) is a polyphenolic compound found in select vegetables and fruits and has been known for its versatility in preventing and reversing a number of diseases including some cancers. Much like SCFAs, RES has the ability to induce programmed cell death in many clinical cancer models. To find out if the SCFAs and RES modulates the different pathways that controls the cancer progression, we utilized prostate cancer (PCa) cell lines to establish a) if, there is any homology between SCFAs produced by normal host epithelial cells and SCFAs produced by host intestinal microflora, and b) assess the in vitro/vivo effectiveness of derived SCFAs utilizing transgenic adenocarcinoma mouse prostate (TRAMP C1, C2, and C3) cell line(s), human prostate cancer cell line (PC-3) and live murine specimens, respectively. Preliminary data indicates that SCFAs and RES together regulate cell death pathways of PCa cells. Additionally, the SCFAs have the capability to manipulate different molecular signatures that directly govern the progression of PCa cells. Therefore, our data suggests that these two compounds (SCFAs and RES) share related biological pathways facilitated by intestinal microflora that can be used to regulate prostate cancer progression and clearance.

Citation Format: James Stokes, Manoj K. Mishra. Impact of microbial metabolites and resveratrol in prostate cancer progression and clearance. [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 908. doi:10.1158/1538-7445.AM2015-908
Abstract 917: The modulatory effects of cancer preventive herbal saponins on gut microbiota and mucosal environment in ApcMin/+ mice
Authors: Chen Lei , Singh Manreet , Leung Frederick CC , Hsiao W.L. Wendy
Published: August 2015

Human gut harbors 100 trillion microbes that is intrinsically linked to individual's health and diseases, including cancer. Triterpenoid saponins are present in many plants and are major active components in medicinal plants. Gynostemma pentaphyllum (Gp) is consumed as herbal tea as well as herbal medicine and found to possess anti-cancer effects in ApcMin/+ mice in our study. Here, we would like to address whether Gp saponins (GpS) can affect the gut microbiota in the ApcMin/+ colorectal cancer mouse model, and whether the alteration would have cancer preventive implication.

Using ERIC-PCR and 16S pyrosequencing analysis, we revealed that GpS treatment altered the overall fecal microbiome. Interestingly, it appeared that GpS treatment enhanced the relatively abundance of the beneficial microbes while reduced the potential harmful sulfate- and sulfur-reducing bacteria lineage. The impact of GpS on the gut mucosal environment was also examined. We found GpS improved the gut barrier function by increasing the numbers of Paneth cells, goblet cells, up-regulating the expression of E-cadherin and down-regulating the expression of N-cadherin in the intestine. In addition, GpS down-regulated the protein expression of beta-catenin and the p-STAT3. Furthermore, higher levels of anti-inflammatory and tissue repair-related cytokines as well as arginase I, but lower level of iNOS expression were found in GpS-treated ApcMin/+ mice. Altogether, GpS might affect the host-microbe interactions by regulating the gut microbial ecosystem and modulating the intestinal mucosal environment, which might contribute to its cancer preventive effect observed in the ApcMin/+ mice.

This study was supported by Macau Science and Technology Development Fund 015/2014/A1 and Research Grants Council of Hong Kong under GRF260413 to WL Wendy Hsiao.

Citation Format: Lei Chen, Manreet Singh, Frederick CC Leung, W.L. Wendy Hsiao. The modulatory effects of cancer preventive herbal saponins on gut microbiota and mucosal environment in ApcMin/+ mice. [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 917. doi:10.1158/1538-7445.AM2015-917
Abstract 92: Epigenetic inhibitors targeting colon cancer stem cells
Authors: Chen Yufeng
Published: August 2015

Colon cancer is one of the top leading causes of death in the world. Even after surgery and chemotherapy, there are still many patients who will experience relapse. Cancer stem or initiating cells (CSCs) are a small subset of self-renewing and highly tumorigenic cells, which are resistant to existing chemotherapy. In addition, CSCs are often enriched following chemotherapy, and are responsible for relapse and subsequent metastasis. One mechanism that possibly leads to chemotherapeutic failure is epigenetic changes which involve aberrant chromatin modifications in cancer and CSCs. Here, we performed microarray to investigate the gene expression profiles of CSCs and non-CSCs populations identified by ALDEFLUOR assay. Several genes were found to be highly expressed in CSCs in different colon cancer cell lines. Then we performed inhibitor screening to identify small molecules which can inhibit CSCs. Several compounds inhibiting histone methylations were found to be effective in reducing the CSCs population and expression of CSCs’ related genes. These results support the use of epigenetic inhibitors together with chemotherapy in refractory colon cancer.

Citation Format: Yufeng Chen. Epigenetic inhibitors targeting colon cancer stem 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 92. doi:10.1158/1538-7445.AM2015-92
Abstract 932: A plasma microRNAs test predicts prognosis and disease status at follow-up in screening-detected lung cancer patients
Authors: Sozzi Gabriella , Sestini Stefano , Boeri Mattia , Verri Carla , Marchiano' Alfonso , Galeone Carlotta , Sverzellati Nicola , La Vecchia Carlo , Pastorino Ugo
Published: August 2015

Background: We previously reported that a miRNA signature classifier (MSC) based on 24 plasma circulating microRNAs is a sensitive and early biomarker for lung cancer, able to increase the specificity of low dose computed tomography (LDCT) in screening trials (Boeri et al. PNAS 2011; Sozzi et al. JCO 2014). In the present study, we have investigated the capacity of plasma MSC to predict prognosis and monitor the disease status at follow-up in LDCT screening detected lung cancer patients.

Methods: Between 2000 and 2010, 3411 heavy smokers were enrolled in a screening program, with annual (2225) or biennial (1186) LDCT. During the first five years of screening, a total of 77 lung cancer patients underwent plasma MSC analysis, with three levels of risk: High, Intermediate or Low. Median follow-up of the alive patients was 4.5 years (Inter Quartile Range, IQR = 6.5). Changes of MSC risk profile at follow-up was assessed in 33 patients, with longitudinal plasma samples (n = 96) collected before and after surgical resection.

Results: Five-year survival was 78% for low- to intermediate risk MSC (median nc), and 35% for High risk MSC (median 2.9 yrs, p<0.01). The prognostic power of MSC persisted when the analysis was restricted to LDCT-detected cases after exclusion of interval cancers (5-years survival: 87% vs. 38% respectively, p<0.01). Within stage I, the 5-years survival was 100% in Low to Intermediate risk MSC and 77% in High risk MSC (p = 0.10). Reduction of MSC risk profile after surgery was observed in 73% of the 26 analyzable subjects who remained disease free, at median time of 18 months (IQR = 24). In all relapsing patients the MSC test returned to Intermediate or High risk at the time of second primary or metastatic progression.

Conclusions: Plasma MSC predicted lung cancer outcome and tumor recurrence at follow-up, showing potential efficacy in LDCT screening and lung cancer management.

Citation Format: Gabriella Sozzi, Stefano Sestini, Mattia Boeri, Carla Verri, Alfonso Marchiano', Carlotta Galeone, Nicola Sverzellati, Carlo La Vecchia, Ugo Pastorino. A plasma microRNAs test predicts prognosis and disease status at follow-up in screening-detected lung cancer patients. [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 932. doi:10.1158/1538-7445.AM2015-932
Abstract 950: Antitumor activity of a novel phosphodiesterase 10 inhibitor in an orthotopic mouse model of lung cancer
Authors: Ramirez-Alcantara Veronica , Schuler Michele , Zhu Bing , Li Nan , Gurpinar Evrim , Otali Dennis , Canzoneri Joshua , Keeton Adam , Gary Bernard , Russo Suzanne , Coward Lori , Gorman Gregory , Grizzle William , Chen Xi , Boyd Michael , Piazza Gary
Published: August 2015

BACKGROUND: We recently reported that phosphodiesterase 10A (PDE10) is elevated in certain tumor types and essential for tumor cell growth (Li et al., Oncogene 2014). Here we evaluate anti-tumor efficacy, pharmacokinetics, tissue distribution, and tolerance of a novel PDE10 inhibitor, ADT-048, in mice. METHODS: ADT-048 was orally administrated to C57BL/6 mice and free levels quantified in plasma and tissues by LC-MS. Anti-tumor activity was evaluated in athymic nude-Foxn1nu mice after inoculating the left lung with 1×106 A549 lung tumor cells transfected with luciferase. Tumor growth was monitored by in situ bioluminescence using the In Vivo Imaging System and efficacy was evaluated by necropsy grading. RESULTS: ADT-048 inhibited A549 lung tumor cell growth with an IC50 value of 0.7 μM, while appreciably higher concentrations were required to inhibit the growth of normal airway epithelial cells (IC50 = 35 μM). Pharmacokinetic studies demonstrated a half-life suitable for once a day dosing, while tissue distribution studies demonstrated a unique capacity to achieve high concentrations in lungs relative to plasma and other tissues. ADT-048, at a dose of 100 mg/Kg, displayed significant anti-tumor activity as evident by reduced luminescence and tumor grading following 28 days of treatment. CONCLUSIONS: A novel PDE10 inhibitor, ADT-048, was found to display highly potent and selective tumor cell growth inhibitory activity in vitro. ADT-048 was well tolerated in mice and had attractive pharmaceutical properties with a unique capacity to achieve high lung concentrations following oral administration. Efficacy studies demonstrate strong anti-tumor activity of ADT-048, which represents a candidate for clinical development. Supported by NIH grants 1R01CA155638 and 1R01CA131378 (Piazza).

Citation Format: Veronica Ramirez-Alcantara, Michele Schuler, Bing Zhu, Nan Li, Evrim Gurpinar, Dennis Otali, Joshua Canzoneri, Adam Keeton, Bernard Gary, Suzanne Russo, Lori Coward, Gregory Gorman, William Grizzle, Xi Chen, Michael Boyd, Gary Piazza. Antitumor activity of a novel phosphodiesterase 10 inhibitor in an orthotopic mouse model of lung 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 950. doi:10.1158/1538-7445.AM2015-950
Abstract 97: CARM1 preferentially methylates H3R17 over H3R26 through a random kinetic mechanism
Authors: Jacques Suzanne L. , Aquino Katrina P. , Gureasko Jodi , Boriack-Sjodin P Ann , Copeland Robert A. , Riera Thomas V.
Published: August 2015

CARM1 (PRMT4) is a type I arginine methyltransferase involved in the regulation of transcription, pre-mRNA splicing, cell cycle progression and the DNA damage response. Overexpression of CARM1 has been implicated in breast, prostate, and colorectal cancers. Since CARM1 appears to be a good target for the development of therapies against these cancers, we studied the substrate specificity and kinetic mechanism of the full-length human enzyme. CARM1 has been shown to methylate both residues R17 and R26 of histone H3. Substrate specificity was examined by testing CARM1 activity with several H3-based peptide substrates using a radiometric assay. Comparison of kcat/KM values reveal that methylation of H3R17 is preferred over H3R26. An R17/R26K peptide produced 8-fold greater kcat/KM value compared to the corresponding R17K/R26 peptide. These effects are KM-driven as kcat values remain relatively constant for the peptides tested. Shortening the peptide at the C-terminus by 5 amino acid residues greatly reduced the specificity (16-24-fold), demonstrating the contribution of distal residues to substrate binding. In contrast, adding residues to the N-terminus of the shortened peptide had a negative effect on activity. CARM1 displays little preference for monomethylated over unmethylated H3R17 (2-5-fold by kcat/KM) suggesting that it operates through a distributive mechanism. Previous crystallographic studies with mouse CARM1 showed that part of the substrate binding groove was formed by cofactor binding, thereby suggesting an ordered kinetic mechanism (Yue et al., EMBO J., 2007). Our results from dead-end and product inhibition studies performed with human CARM1, however, are consistent with a random kinetic mechanism. SAH and sinefungin demonstrate competitive inhibition with respect to SAM and produced noncompetitive inhibition patterns with respect to peptide. Both dimethylated R17 product peptide and dead-end R17K peptide exhibited noncompetitive inhibition patterns with respect to SAM. Furthermore, binding of SAM and peptide substrates were shown to be independent of each other in initial velocity experiments where both substrates were varied. Together, these results elucidate the kinetic mechanism of CARM1 and highlight elements important for binding affinity.

Citation Format: Suzanne L. Jacques, Katrina P. Aquino, Jodi Gureasko, P Ann Boriack-Sjodin, Robert A. Copeland, Thomas V. Riera. CARM1 preferentially methylates H3R17 over H3R26 through a random kinetic mechanism. [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 97. doi:10.1158/1538-7445.AM2015-97
Abstract 98: Genetic alterations of KDM4 subfamily and therapeutic effect of novel demethylase inhibitor in breast cancer
Authors: Holowatyj Andreana N. , Ye Qin , Wu Jack , Liu Hui , Zhang Lihong , Suzuki Takayoshi , Yang Zeng-Quan
Published: August 2015

The histone lysine demethylase KDM4 subfamily, comprised of four members (A, B, C, and D), play critical roles in controlling transcription, chromatin architecture and cellular differentiation. Although KDM4 family members have a high degree of homology, they may play different roles in various types of breast cancer. The goal of this study is to analyze the genomic and transcriptomic alterations of the KDM4 subfamily in different subtypes of breast cancer, and explore the therapeutic potential of a novel KDM4 inhibitor in aggressive basal breast cancer.

We conducted a large-scale meta-analysis of KDM4A, B, C, and D in breast cancer and identified associations among recurrent copy number alterations, gene expression and breast cancer subtypes. We examined KDM4 expression in a panel of non-tumorigenic and cancerous breast epithelial cell lines using quantitative RT-PCR and Western blot assays, and assessed global histone 3 methylation levels by Western blot in a panel of breast cancer cell lines. Next, we tested a novel inhibitor of the KDM4 demethylases, small molecule NCDM-32B, for its ability to attenuate basal breast cancer cell growth and impair metastatic potential. Finally, to examine gene expression changes induced by NCDM-32B, we conducted expression profiling and pathway analyses.

We found that the KDM4 members show different expression patterns in subtypes of breast cancer. Our findings suggest that H3 global methylation levels vary among different breast cancer cell lines. We demonstrated that NCDM-32B significantly impaired viability, cellular growth and transforming phenotypes of basal breast cancer in vitro. Furthermore, NCDM-32B impaired several critical pathways and classical oncogenes, including MET, CDC26, and CDK6, that drive cellular proliferation and transformation in breast cancer.

In summary, our findings add layers of information to the genomic and transcriptomic profiles of the KDM4 subfamily in different subtypes of breast cancer. We provide the first evidence that a novel KDM4 demethylase inhibitor, the small molecule NCDM-32B, led to significant inhibition of cellular growth of basal breast cancer in vitro. These findings lay the foundation for evaluating KDM4 inhibitors as therapeutic approaches against aggressive breast cancer.

Citation Format: Andreana N. Holowatyj, Qin Ye, Jack Wu, Hui Liu, Lihong Zhang, Takayoshi Suzuki, Zeng-Quan Yang. Genetic alterations of KDM4 subfamily and therapeutic effect of novel demethylase inhibitor in breast 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 98. doi:10.1158/1538-7445.AM2015-98
Abstract 983: Gas6/Axl mediation of prostate cancer cell dormancy requires cooperation with additional bone marrow niche components
Authors: Axelrod Haley , Pienta Kenneth J.
Published: August 2015

Early metastatic events are often responsible for the recurrence and lethality of prostate cancer. The most frequent site of metastasis is the bone marrow, where small populations of disseminated tumor cells (DTCs) preferentially take residence in the hematopoietic stem cell (HSC) niche. These micro-metastases may survive in a benign, dormant state for years before they become “reawakened” to form full metastases, and are thus difficult to detect and treat. It is unknown what induces and maintains DTC dormancy, and it remains a key question with regard to metastatic prostate cancer treatment and prevention strategies. An essential component of the HSC niche is the osteoblast population to which DTCs bind for support and uptake of secreted factors. We have previously shown that dormant DTCs in the HSC niche display high levels of the receptor tyrosine kinase Axl, and are bound to osteoblasts that secrete its ligand, Gas6. The requirement of Gas6/Axl in DTC dormancy is striking in vivo, but in vitro is not replicable. Addition of Gas6 to prostate cancer cells expressing Axl does not have a significant inhibitory effect on cell proliferation, suggesting the cooperation with other niche factors absent in culture. As the elements of the DTC niche are still being actively explored, this study further supports the complex nature of the mechanisms governing DTC dormancy and preferential survival in the bone marrow niche. Selective targeting of these elements may allow for long term maintenance of the benign, dormant state of DTCs, or coerced reawakening to a more chemotherapy-sensitive state.

Citation Format: Haley Axelrod, Kenneth J. Pienta. Gas6/Axl mediation of prostate cancer cell dormancy requires cooperation with additional bone marrow niche components. [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 983. doi:10.1158/1538-7445.AM2015-983
Abstract CT208: Preliminary results of a phase II trial of an adenovirus/PSA vaccine in men with recurrent prostate cancer
Authors: Lubaroff David M. , Vaena Daniel , Brown James , Nepple Kenneth , Zehr Pamela , Griffith Karen , Brown Erica , Eastman Julie , Zamba Gideon , Williams Richard
Published: August 2015

Introduction and Objectives: A phase II clinical trial of an adenovirus/PSA (Ad/PSA) vaccine was carried out in men with recurrent prostate cancer using two protocols. The objectives of the study were to determine whether the vaccine produced beneficial immune and clinical responses in men with a low burden of tumor.

Methods: In Protocol #1 men with recurrent prostate cancer following definitive initial treatment for their disease were placed in one of two arms: Arm A; men received the vaccine alone at days 0, 30, and 60; Arm B; men received the vaccine 14 days after the initiation of androgen deprivation therapy (ADT). In Protocol #2 men with hormone refractory disease received the vaccine alone using the same 3 injection schedule. Each injection consists of 108 pfu of the Ad/PSA vaccine suspended in a collagen matrix. All patients returned at regular intervals for physical, chemical, radiologic, and immunologic evaluations.

Results: We enrolled all of our targeted 82 patients, 50 in protocol 1 (25 Arm A, 25 Arm B) and 32 in protocol 2. All patients have been followed a minimum of 12 months with the longest being over 6 years. Eighty nine percent (89%) of all patients produced anti-PSA T cell immune responses; 71% in protocol 1 Arm A, 100% in protocol 1 Arm B, and 100% in protocol 2. Clinically, 58% of patients in protocol 1 Arm A and 75% of patients in protocol 2 demonstrated a decrease in serum PSA or an increase in PSA doubling times (PSADT). As of the submission date the PSA levels of 2 patients declined to 0.07 ng/ml and undetectable (<0.03).

Conclusions: Preliminary results of patients thus far studied in a phase II clinical trial of the Ad/PSA vaccine are very encouraging, demonstrating both immunologic and clinical responses to the 3-vaccination therapy. PSA responses indicate at least a decline in the growth and perhaps a destruction of recurrent prostate tumors in men immunized in two separate protocols. Data collection continues that include completion of immune assays on all 82 patients as well as monitoring PSA levels, PSADT, and radiologic changes.

Citation Format: David M. Lubaroff, Daniel Vaena, James Brown, Kenneth Nepple, Pamela Zehr, Karen Griffith, Erica Brown, Julie Eastman, Gideon Zamba, Richard Williams. Preliminary results of a phase II trial of an adenovirus/PSA vaccine in men with recurrent prostate 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 CT208. doi:10.1158/1538-7445.AM2015-CT208