Citations

Abstract The mechanical and chemical properties of the cellular microenvironment can influence the phenotype of cancer cells. The hypoxic conditions within solid breast tumors can contribute to invasiveness and the formation of breast cancer stem cells (CSCs). Integrin-linked kinase (ILK) is a critical mediator for mechanotransduction, a process that converts exogenous mechanical stimuli into biochemical signals. Yet, it is unclear how the physical properties of the tumor microenvironment, including matrix stiffness and hypoxia, integrate to direct the formation of the breast CSC niche. Using an innovative engineered culture model, we found that stiff and hypoxic microenvironments activate integrin signaling and a stem-like gene signature in breast cancer cells, suggesting that integrin signaling, matrix mechanics and oxygen tension cooperatively promote the formation of breast CSCs. Stiff and hypoxic microenvironments promote integrin signaling and the expression of CSC markers including CD44 and Nanog. Knocking down ILK reverts the CSC phenotype of invasive breast cancer cells on stiff matrix, and abrogates their ability to form mammospheres and colonies in soft agar. In contrast, ectopic expression of ILK enhances CSC properties. ILK promotes integrin signaling and the CSC phenotype through the PI3K/Akt pathway. Stiff microenvironments promote tumor formation and metastasis in ovo. ILK depletion significantly abrogates the tumorigenenic and metastatic potential of invasive breast cancer cells in ovo. Importantly, we found that breast cancer cells expressing ILK and the CSC marker CD44 were only present in the regions of tumors predicted to be stiff in breast cancer patient samples. Our data suggest that ILK act as an essential mechanosensor that regulates breast CSC phenotype in response to matrix mechanics and oxygen tension to regulate the formation of breast CSCs. Citation Format: Mei-Fong Pang, Melody Stallings-Mann, Michael J. Siedlik, Victor D. Varner, Siyang Han, Derek C. Radisky, Celeste M. Nelson. Tissue stiffness and hypoxia regulate breast cancer stem cells through ILK. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4395.

Abstract Background: Associations of medical history, lifestyle, and family history of hematological disorders with risk of chronic lymphocytic leukemia (CLL) have been previously established (1), but these exposures have not been well-studied as contributing factors to CLL prognosis. Here we investigate the association of these exposures with time to first treatment (TTFT) in 730 CLL patients. Methods: Newly diagnosed CLL patients seen at the Mayo Clinic between 2002 and 2012 were enrolled. CLL was defined according to the 1996 NCI-Working Group criteria (2). Risk factor data (including body mass index, smoking, alcohol use, sun exposure, having lived on a farm, any allergy, asthma, eczema, blood transfusion, diabetes, rheumatoid arthritis, and family history of hematological malignancy) were collected from self-administered questionnaires. Clinical and prognostic characteristics for CLL were extracted from medical records. Analyses were performed using Cox regression with first treatment as the event. Hazard ratios (HR) and 95% confidence intervals were estimated. We used Bonferroni correction for multiple testing with statistical significance at 0.004. Results: The median age at CLL diagnosis was 63 years (range 36 - 89); 65% were male, and 95% had a Rai stage< III. The median follow up time was 6.3 years, and 40% received treatment. In unadjusted analyses, patients with any history of allergies had significantly longer TTFT (HR = 0.66, 95% CI: 0.51-0.85, P = 0.001). We also observed borderline significance with history of asthma (HR = 0.53, 95% CI: 0.34-0.85, P = 0.008). These associations held after adjusting for important prognostic factors including age, sex, Rai stage, and IGVH mutational status. The other risk factors had non-significant associations (P>0.1). Conclusions: We observed an improved CLL prognosis in patients with a history of any allergies or asthma. These results were independent of other prognostic markers and suggest that an overactive IgE level from environmental exposures may provide insight into the progression of CLL. Literature Cited 1. Slager SL, Benavente Y, Blair A, Vermeulen R, Cerhan JR, Costantini AS, et al. Medical history, lifestyle, family history, and occupational risk factors for chronic lymphocytic leukemia/small lymphocytic lymphoma: the InterLymph Non-Hodgkin Lymphoma Subtypes Project. J Natl Cancer Inst Monogr. 2014 Aug;2014(48):41-51. 2. Cheson BD, Bennett JM, Grever M, Kay N, Keating MJ, O’Brien S, et al. National Cancer Institute-sponsored Working Group guidelines for chronic lymphocytic leukemia: revised guidelines for diagnosis and treatment. Blood. 1996 Jun 15;87(12):4990-7. Citation Format: Sara Beiggi, James M. Foran, O’Byrne Megan, Celine M. Vachon, Timothy G. Call, Neil E. Kay, Tait D. Shanafelt, James R. Cerhan, Susan L. Slager. Medical history, lifestyle, and family history exposures and chronic lymphocytic leukemia outcome. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3453.

Abstract Purpose: Expression of the tumor suppressor gene E-cadherin is diminished in lobular breast cancers and has been implicated in epithelial mesenchymal transition. We assessed risk factor associations for breast cancer stratified by low vs. high E-cadherin protein expression in a pooled analysis within the Breast Cancer Association Consortium (BCAC) studies. Methods: E-cadherin tumor tissue staining was performed centrally at the NCI on formalin-fixed paraffin-embedded tissue microarray (TMA) sections representing 6,010 breast cancer patients from 12 US and European BCAC studies. TMAs were digitally scanned and scored using the SlidePath Digital Image Hub (Leica Biosystems, Wetzlar, Germany). For 5,896 cancers with evaluable tumors, E-cadherin was visually scored as estimated percent of positive cells times stain intensity (0, 1+, 2+, 3+) (score range 0-300). E-cadherin low was defined as tumors with a score < 100. Risk factor associations for low vs. high E-cadherin expressing tumors were evaluated by logistic regression, adjusted for age and study site, and stratified by ER status and histologic subtype. To assess the consistency in results by study, meta-analyses were performed using the random-effects model. All statistical tests were two-sided. Results: E-cadherin low cancers comprised 20% of tumors and were associated with lobular histology, well/moderately differentiated cancers, > 2cm in size, and HER2-negative status (χ2, P < 0.003 for all factors). E-cadherin low status was associated with family history of breast cancer (FH) (OR = 1.32, 95% CI = 1.09-1.60, P-het = 0.005) and ever use of menopausal hormones (OR = 1.26, 95% CI = 1.02-1.56, P-het = 0.03). Study specific meta-plots showed consistent effects across studies for menopausal hormone therapy (I2 = 0.0%, p = 0.64); however, E-cadherin loss by FH did show evidence of heterogeneity by study (I2 = 54%, P = 0.03). Differences in E-cadherin expression remained significant for FH, and menopausal hormone use when further adjusted for ER (P < 0.05). We also found relationships with E-cadherin loss to vary by BMI, number of live births, age at first birth, and oral contraceptive use in stratified analysis by ER status and histologic subtype. Conclusion: This large pooled analysis shows that breast cancer risk factor associations may differ by E-cadherin expression independent of ER status, suggesting that it may represent a marker of etiologic heterogeneity. Citation Format: Hisani N. Horne, Hannah Oh, Mark E. Sherman, Maya Palakal, Stephen H. Hewitt, Marjanka Schmidt, Javier Benitez, Roger Milne, Hermann Brenner, Heli Nevanlinna, Arto Mannermaa, Georgia Chenevix-Trench, Fergus Couch, Peter Devilee, Diana Eccles, Maartje Hooning, Anthony J. Swerdlow, Nick Orr, Melissa A. Troester, Renata Cora, Paul D. Pharoah, Montserrat Garcia-Closas, Jonine D. Figueroa. Breast cancer risk factor associations by loss of E-cadherin tumor tissue expression: A pooled analysis of 5,896 cases in 12 studies from the Breast Cancer Association Consortium (BCAC). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3451.

Abstract Background: Numerous epidemiologic studies have examined the association between aspirin (ASA), non-steroid anti-inflammatory drugs (NSAIDs) and the development of glioma, but the results have been inconsistent. The goal of this study was to evaluate the relationship between the intake of these drugs and glioma risk in a large, international case-control study. Methods: Between 2010 and 2015, the Glioma International Case-Control Study (GICC) recruited newly diagnosed glioma cases and matched controls in 14 different sites across five countries. Each subject was interviewed using a standardized questionnaire to obtain NSAIDs and ASA use. We examined the associations between ever use (at least > 6 months), duration of drug use and glioma histology. Ever use data on 4533 glioma cases and 4171 controls was combined using maximum likelihood estimation/restricted maximum likelihood meta-analysis methods. Furthermore, based on a priori hypotheses, we performed subgroup analyses based on gender and glioma histological grades. Results: Use of ASA for > 6 months was associated with a 33% lower glioma risk compared to those who never took it (adjusted Meta-OR 0.67, 95% CI 0.54-0.83). Duration of intake showed a significant trend test (p < 0.0001), with ORs became lower for increasing number of years of ASA use. In subgroup analyses, intake of ASA was significantly associated with glioma risk in both men and women (adjusted Meta-OR = 0.65, 95% CI 0.51-0.84 for men; adjusted Meta-OR = 0.74, 95% CI 0.58-0.93 for women). ASA intake was protective for grade IV glioma (glioblastoma) and grade II/III glioma (adjusted meta-OR 0.63, 95% CI 0.5-0.8 for glioblastoma; adjusted meta-OR 0.67, 95% CI 0.50 - 0.89 for grade II/III glioma). For NSAIDs intake, ever use > 6 months was not associated with glioma risk (adjusted meta-OR 0.87, 95% CI 0.71-1.07). However, NSAIDs use was protective for women (adjusted meta-OR 0.72, 95% CI 0.55-0.93) in subgroup analyses but not for men (adjusted meta-OR 1.03; 95% CI 0.86-1.23). The interaction between gender, NSAIDs and glioma risk was significant (p-value 0.0076).. Sensitivity analyses excluding those who took ASA or NSAIDs within the past 12 months for headache, and the removal of proxy respondents did not change our results. Conclusion: ASA was associated with a significant protective effect for glioma, but NSAIDs were only associated with reduced glioma risk in women. Given the possibility of recall bias in case-control studies of brain tumors, we may verify dosage and duration of drug intake in those countries with electronic pharmacy records within the GICC. Citation Format: Rose K. Lai, Renke Zhou, E. Susan Amirian, Christoffer Johansen, Michael E. Scheurer, Georgina N. Armstrong, Ching C. Lau, Elizabeth B. Claus, Jill S. Barnholtz-Sloan, Dora Il’yasova, Joellen Schildkraut, Francis Ali-Osman, Siegal Sadetzki, Richard Houlston, Robert B. Jenkins, Daniel Lachance, Sara H. Olson, Jonine L. Bernstein, Ryan T. Merrell, Margaret R. Wrensch, Faith G. Davis, Sanjay Shete, Christopher I. Amos, Beatrice S. Melin, Melissa Bondy. Aspirin, non-steroidal anti-inflammatory drugs (NSAIDs) and the risk of glioma: Results from the Glioma International Case Control Study. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3446.

Abstract Background Myelodysplastic syndromes (MDS) are a group of clonal hematologic disorders that result in ineffective hematopoiesis. Individuals with MDS have a high risk of progressing to leukemia, with approximately 30% expected to develop acute myeloid leukemia (AML). Benzene exposure is one of the few well-established risk factors for AML, and recent studies suggest it is also a risk factor for MDS. Exposure to other occupational and residential chemicals has been inconsistently associated with hematologic malignancies. In this analysis, we evaluated occupational and residential chemical exposures as risk factors for AML and MDS using population-based data. Methods AML and MDS cases were identified by rapid case ascertainment through the Minnesota Cancer Surveillance System (MCSS). Centralized pathology and cytogenetics reviews were conducted to confirm diagnosis and classify by subtypes. Controls were identified through the Minnesota State driver's license/identification card list. Chemical exposures were measured by self-report and included occupational and residential exposure to a variety of chemicals. Unconditional logistic regression with adjustment for age, sex, previous cancer treatment, income, and farm or rural residence was used to calculate crude and adjusted odds ratios (ORs) and 95% confidence intervals (CI). Smoking, obesity and physical activity were considered as potential confounders but did not change effect estimates by 10% or more. Results We included 265 MDS cases, 420 AML cases, and 1388 controls in this analysis. As expected, we observed significant associations between benzene and both MDS and AML (OR = 1.77, 95% CI 1.17, 2.67 and OR = 2.03, 95% CI 1.45, 2.83, respectively). Exposure to vinyl chlorides was associated with MDS (OR = 2.25, 95% CI 1.32, 3.81) but not with AML (OR = 1.36, 95% CI 0.83, 2.21). Exposure to fertilizers (OR = 1.70, 95% CI 1.11, 2.59), soot (OR = 2.64, 95% CI 1.59, 4.39), creosote (OR = 1.95, 95% CI 1.08, 3.51), inks, dyes and tanning solutions (OR = 1.63, 95% 1.02, 2.60), and coal dust (2.64, 95% CI 1.30, 5.39) were associated with AML, while no association was seen between any of these exposures and MDS (range ORs = 0.78-1.25). No significant associations were observed for occupational pesticide exposures in either group. Discussion These data confirm the importance of benzene as a risk factor for myeloid malignancy and provide risk estimates in a population-based sample. A number of other significant associations with occupational and residential chemicals were observed for AML; however, all exposures were reported by only a small percentage of cases (≤10%). While chemical exposures play a clear role in the etiology of myeloid malignancy, these exposures do not account for the majority of cases. Citation Format: Jenny N. Poynter, Michaela Richardson, Michelle Roesler, Cindy K. Blair, Betsy Hirsch, Phuong Nguyen, Adina Cioc, James R. Cerhan, Erica Warlick. Chemical exposures and risk of acute myeloid leukemia and myelodysplastic syndromes in a population-based study. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3427.

Abstract Previous studies have shown an increased risk of colorectal cancer (CRC) among moderate to heavy alcohol consumers relative to non-drinkers; however, the relationship between alcohol and CRC survival remains unclear. Using data from the international Colon Cancer Family Registry (CCFR), we assessed the association between pre-diagnostic alcohol intake and survival outcomes after CRC diagnosis, overall and stratified by patient and tumor attributes. CRC cases were identified via population-based cancer registries at four CCFR study sites, with diagnoses of incident, invasive CRC from 1997 to 2006. Study participants completed a risk factor questionnaire at enrollment which included information on several pre-diagnostic behaviors, including consumption of wine, beer, and liquor. Prospective follow-up for survival outcomes was conducted for 4858 CRC cases with complete data on alcohol consumption. Using Cox proportional hazards regression models with delayed entry to account for the time between diagnosis and study enrollment, we compared non-drinkers (i.e., alcohol intake <1 drink per week) to individuals who consumed, on average, <1 serving of alcohol per day (but ≥1 per week), and those who consumed ≥1 serving per day in the years preceding CRC diagnosis. Separate analyses were carried out for overall and disease-specific survival. All models were adjusted for age at diagnosis, sex, study site, year of diagnosis, smoking history, CRC screening history, and body mass index. Over a mean follow-up of 7.5 years, 1872 (39%) study participants died, 1110 (59%) of whom died from CRC. Pre-diagnostic beer and liquor consumption were not associated with CRC survival; however, consumption of ≥1 serving of wine per day was modestly associated with more favorable overall [hazard ratio (HR) = 0.80, 95% confidence interval (CI): 0.63-1.00] and disease-specific survival (HR = 0.83, 95% CI: 0.62-1.12). In stratified analyses, having consumed ≥1 serving of wine per day was slightly, but not statistically significantly, more strongly associated with overall survival among men than among women (HR = 0.71 vs. 0.91, respectively, p-heterogeneity = 0.12) and among those aged ≤50 than those aged >50 years (HR = 0.66 vs. 0.84, p-heterogeneity = 0.35). Similar patterns were noted with respect to disease-specific survival. There were no differences in the relationships between wine consumption and survival outcomes stratified by tumor site, microsatellite instability, BRAF-mutation, or CpG island methylator phenotype status. These results suggest that wine consumption prior to CRC diagnosis is modestly associated with more favorable survival after CRC diagnosis. This modest inverse association does not appear to be limited to specific colorectal tumor subtypes and extends beyond overall survival to disease-specific outcomes. Citation Format: Amanda I. Phipps, Jamaica Robinson, Peter T. Campbell, Aung Ko Win, Jane Figueiredo, Noralane M. Lindor, Polly A. Newcomb. Prediagnostic alcohol consumption and colorectal cancer survival: the Colon Cancer Family Registry. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3425.

Abstract Breast density represents the stromal and epithelial tissue in the breast and is a strong risk factor for breast cancer. Reductions in breast density attributable to tamoxifen (TAM) and aromatase inhibitors (AI) may be associated with reduced risk of first primary and subsequent breast cancer. Studies assessing breast density changes have principally used two-dimensional measures. We assess changes in breast density following initiation of TAM and AI using two automated volumetric density measures that have shown strong associations to breast cancer risk. Breast cancer cases with a full field digital mammogram (FFDM) prior to diagnosis (index mammogram) and after initiation of TAM (n = 379) or AI (n = 425) were identified from the Mayo Clinic Mammography Practice and the San Francisco Mammography Registry. Volumetric percent density (VPD) and dense volume (DV) were measured on 4-view FFDM using VolparaTM (Matakina Technology) and QuantraTM (Hologic) automated software. We used linear regression to assess the effect of treatment on mean annualized change in VPD and DV (change from index to last mammogram divided by time interval) for each software type, adjusting for age, body mass index (BMI) and density at index mammogram. The median time between index mammogram and cancer diagnosis was 0.6 months (IQR: 0.2, 2.2) and median time between index and last mammogram was 3 years (IQR: 2.0, 3.9). Women on TAM were younger, had lower BMI and higher baseline VPD and DV relative to women on AI (Table). An annual decrease in VPD and DV was observed with both TAM and AI. Both Volpara and Quantra estimated a similar magnitude of change in VPD in women on TAM and AI, and a greater change in DV with TAM. Our findings suggest that both Volpara and Quantra can assess volumetric changes in breast density among women on hormone therapy. If declines in volumetric density correlate with a reduction in breast cancer risk, these automated measures could be used in clinical practice to assess response to therapy. Annualized changes in volumetric breast density estimated by linear regression.Tamoxifen (n = 379)Aromatase Inhibitors (n = 425)Baseline Median (IQR)Annualized Change (95% CI)*Baseline Median (IQR)Annualized Change (95% CI)*Age at Diagnosis50.0 (45.0, 60.0)–63.0 (58.0, 71.0)–Body Mass Index (BMI)23.6 (21.5, 26.8)–25.7 (22.7, 29.9)–Time Interval¥3.0 (2.1, 3.9)–3.0 (2.1, 3.9)–VolparaPercent Density (VPD,%)11.6 (6.8, 18.8)-0.17 (-0.27, -0.10)7.2 (5.0, 11.0)-0.19 (-0.29, -0.12)Dense Volume (DV, cm3)64.7 (45.4, 90.9)-0.90 (-1.45, -0.48)51.9 (38.9, 69.9)-0.52 (-0.93, -0.23)QuantraPercent Density (VPD,%)14.5 (9.2, 20.2)-0.42 (-0.59, -0.28)9.9 (7.1, 14.5)-0.38 (-0.54, -0.25)Dense Volume (DV, cm3)94.0 (58.0, 144.0)-2.20 (-3.52, -1.19)80.0 (49.0, 128.0)-0.95 (-1.85, -0.35)IQR = Interquartile range ¥ Median number of years between index mammogram and last mammogram post-initiation of therapy. *Annualized change estimated as change from index to last mammogram divided by time interval and adjusted for study site, age at diagnosis, BMI and density at index mammogram. Citation Format: Natalie J. Engmann, Celine M. Vachon, Christopher G. Scott, Matthew R. Jensen, Lin Ma, Kathleen R. Brandt, Amir P. Mahmoudzadeh, Serghei Malkov, Dana H. Whaley, Carrie B. Hruska, Fang F. Wu, Stacey J. Winham, Diana L. Miglioretti, Aaron D. Norman, John J. Heine, John Shepherd, V Shane Pankratz, Karla Kerlikowske. Longitudinal changes in volumetric breast density with adjuvant endocrine therapy among women with breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3424.

Abstract Introduction. Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of paclitaxel treatment. There is conflicting data on the benefits and harms of supplement use for the treatment and prevention of CIPN. We examined dietary supplement use before diagnosis and during treatment in relation to CIPN among breast cancer patients registered to a clinical trial (SWOG 0221; ClinicalTrials.gov Identifier: NCT00070564) before diagnosis and during treatment in relation to CIPN. Methods. At trial registration (baseline), breast cancer patients (n = 1,225) completed questionnaires to capture use before and at diagnosis of multivitamins and other dietary supplements. Of these patients, 1,068 completed a 6-month follow-up questionnaire to capture use during treatment. We examined the use of multivitamins, vitamins C, D, E, B6, and B12, folic acid, iron, calcium, glucosamine, and combined fish oil, eicosapentaenoic acid (EPA), omega-3, flaxseed and cod liver oil at these timepoints in relation to CIPN. CIPN was assessed via the National Cancer Institute Common Toxicity Criteria for Adverse Events (CTCAE) and the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group Neurotoxicity (FACT/GOG-Ntx) subscale. Odds ratios and 95% confidence intervals were computed using unconditional logistic regression. Results. Multivitamin use before diagnosis was associated with reduced symptoms of CIPN (CTCAE adjusted OR = 0.60, 95% CI = 0.42-0.87; FACT/GOG-Ntx adjusted OR = 0.78, 95% CI = 0.61-1.00). Although in a similar direction as use prior to diagnosis, multivitamin use during treatment was less strongly associated with CIPN (CTCAE adjusted OR = 0.73, 95% CI = 0.49-1.08; FACT/GOG-Ntx 0.77, 95% CI = 0.60-0.99). Other supplement use, either before diagnosis or during treatment, was not associated with CIPN. Conclusions. Our results indicate that supplement use during treatment may not appreciably affect experience of CIPN symptoms. Future analyses of the relationships between supplement use and survival outcomes will better inform patient decision making. Acknowledgments: supported by R01 CA116395 (CBA); S0221 supported, in part, by National Cancer Institute/Division of Cancer Prevention SWOG NCORP Research Base grant 5UG1CA189974-02; National Cancer Institute (NCI), National Clinical Trials Network (NCTN): CA180888, CA180819; and in part by Amgen, Inc. Citation Format: Gary R. Zirpoli, Susan E. McCann, Lara E. Sucheston-Campbell, Dawn L. Hershman, Gregory Ciupak, Warren Davis, Joseph M. Unger, Halle C.F. Moore, James A. Stewart, Claudine Isaacs, Timothy J. Hobday, Muhammad Salim, Robert B. Livingston, Gabriel N. Hortobagyi, Julie R. Gralow, Daniel F. Hayes, G. Thomas Budd, Kathy S. Albain, Christine B. Ambrosone. Supplement use and chemotherapy-induced peripheral neuropathy in breast cancer patients treated on SWOG study S0221. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3413.

Abstract BACKGROUND: Talazoparib (TAL) is a potent poly (ADP-ribose) polymerase (PARP) inhibitor that robustly enhances in vitro sensitivity to temozolomide (TMZ) in several tumor models. We assessed the in vitro and in vivo efficacy of TAL combined with TMZ in glioblastoma (GBM) models. METHODS: Established glioma cell lines (T98G, U251) and the GBM12 patient derived xenograft (PDX) line were treated in vitro with TAL (1-10 nM) ± TMZ (2-300 μM). Antitumor efficacy was assessed with CyQUANT, clonogenic and primary neurosphere assays; cell cycle analysis with flow cytometry; DNA damage signaling with phospho-specific western blots for pKap1, pChk1, pChk2 and fluorescent immunocytochemistry for γH2AX and replication protein A foci. Brain and plasma concentrations of TAL in wild-type (WT), Mdr1a/b(-/-), Bcrp(-/-) and Mdr1a/b(-/-)Bcrp(-/-) knockout (KO) mice were assessed with LC-MS/MS. The tolerability of TAL (0.05 - 0.30 mg/kg/day orally, divided twice daily (div. bid)) and TMZ (5-50 mg/kg/day orally) was tested in athymic nude mice. Subsequently, in vivo combination TAL/TMZ efficacy was assessed with survival analyses in intracranial and flank GBM12 PDX models. RESULTS: TAL 1-3 nM sensitizes the TMZ resistant T98G glioma cell line to TMZ at high TMZ concentrations (30-300 μM) and is associated with G2 cell cycle arrest and enhanced DNA damage signaling. TAL 1-3 nM also enhances the cytotoxic efficacy of lower concentrations of TMZ (10-30 μM) in the TMZ sensitive U251 cell line. At least 3 nM TAL is required to enhance the in vitro efficacy of low TMZ concentrations (2-10 μM) in the TMZ sensitive GBM12 PDX line. PK studies in non-tumor bearing WT FVB mice treated with a single dose of TAL 0.15 mg/kg revealed mean brain and plasma concentrations of 0.49 ng/g (1.3 nM) and 25.5 ng/ml (67.1 nM) respectively at 2 hours. The mean brain/plasma ratio at 2 hours was unchanged in Bcrp(-/-) KO mice compared to WT mice (1.2% vs. 2.0%), but was significantly increased in Mdr1a/b(-/-) KO mice (22.8%) and Mdr1a/b(-/-)Bcrp(-/-) KO mice (23.9%). Standard doses of TMZ (50 mg/kg/day, days 1-5) combined with low doses of TAL (0.05 mg/kg/day, div. bid) were toxic in nude mice. Higher doses of TAL (0.30 mg/kg/day, div. bid) required substantial TMZ dose reductions (5 mg/kg/day, days 1-5) for tolerability. The addition of TAL (0.30 mg/kg/day, div. bid) to low-dose TMZ (5 mg/kg/day) prolonged tumor stasis in flank GBM12 xenografts (median time to endpoint 76 vs. 50 days, p = 0.005). However this regimen was ineffective in intracranial GBM12 xenografts (median survival 37 vs. 30 days, p = 0.93). CONCLUSIONS: TAL is a potent PARP inhibitor that enhances the efficacy of TMZ in both in vitro GBM models and flank GBM12 PDX models, but not in the corresponding GBM12 intracranial xenografts. This lack of intracranial efficacy is associated with limited brain distribution due to active efflux mediated by Mdr1 at the blood-brain barrier. Citation Format: Sani H. Kizilbash, Kenneth Chang, Shiv K. Gupta, Ryo Kawashima, Karen Parrish, Ann C. Mladek, Brett L. Carlson, Katrina K. Bakken, Mark A. Schroeder, Gaspar J. Kitange, Paul A. Decker, Yuqiao Shen, William F. Elmquist, Jann N. Sarkaria. Talazoparib enhances low-dose temozolomide efficacy in flank glioblastoma models, but intracranial efficacy is constrained by limited brain distribution. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 340.

Abstract Background: Little transcriptomic research has compared epithelial ovarian cancer (EOC) histological subtypes. We set out to characterize the transcriptomes of high-grade serous carcinomas (HGSC) and endometrioid carcinomas (EC), which make up around 70% and 20% of EOC tumors, respectively, and have some histopathological similarities. Methods: Fresh frozen tumors from EOC patients seen at the Mayo Clinic (30 EC and 62 HGSC) were used. 1ug RNA riboZero was used for library preparation using the Illumina TruSeq kit and sequenced on a HiSeq 2000 machine. Reads were aligned using TopHat2 followed by quantification of abundances using RSEM and differential expression analysis with edgeR. We analyzed transcriptomes, conducted pathway analyses, and summarized key candidate gene sets. Expressed SNVs (eSNVs) from the RNA-seq data were determined using GATK and RVboost. Results: The analysis found 699 genes with FDR < 1×10-5 for differential expression between HGSC and EC, with most genes being up-regulated in EC. The top most associated genes were TPH1, MAP2K6, KLK2, ADAM23, TESC and TRAF3IP2 (p<10-22). Pathway analysis of the genes up-regulated in EC revealed enrichment of the “basal cell carcinoma signaling pathway” (p = 1.2×10-5). Within 1 Mb of the 25 known EOC risk loci, we observed higher expression in HGSC for RSPO1 and HPSE (p <5×10-7). For genes functionally related to EOC, we observed in HGSC up-regulation (*p < 10-5, ⁁p<0.003) for FOXM1⁁, CDKN2A⁁, CCNE1*, CCND2⁁, PIK3CA*, BRCA2⁁, BIRC5⁁, MMP9⁁, FANCD2⁁, and MAML2⁁. In contrast, we found up-regulation in EC for MDM2*, KLK4*, BCL2⁁, CCND1*, ANXA4*, CDH1⁁, MMP7⁁, and MAML3⁁. We also identified 204 eSNVs (44 non-synonymous) associated with EC v HGSC subtype (p<10-4); this included an exonic TRAF3IP2 eSNV (66% EC, 13% HGSC, p = 4×10-7, chr6:111877117). Discussion: Using one of the largest sets of identically processed fresh-frozen EOC tumors, some patterns emerged among the numerous EC v HGSC transcriptomic differences. TPH1, up-expressed in EC, is regulated by SOX4 which was also up-regulated in EC. Two sets of genes related to Kallikreins serine proteases were differentially expressed, including KLK2 which is known to regulate EGFR and pro-inflammatory cytokines and is regulated by MYC. Lastly, TRAF3IP2 encodes for a protein involved in regulating cytokines through members of the NFKB pathway. Conclusions: These findings suggest important biological insights into one of the rarer EOC histologies and may aid in the development of targeted treatment options. Research is on-going to incorporate additional features (e.g., DNA methylation, copy number) into a “systems biology” framework to better understand the molecular differences between EOC histologies. Citation Format: Brooke L. Fridley, Junqiang Dai, Rama Raghavan, Chen Wang, Pengcheng Lu, Stacey Winham, Madalene Earp, Kate Lawrenson, Simon A. Gayther, Kimberly R. Kalli, Ellen L. Goode. Transcriptome characterization of high grade serous and endometrioid epithelial ovarian cancer tumors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1833.