Citations

Abstract Background:BRCA1 and BRCA2 mutation carriers are at substantially increased risk for developing breast and ovarian cancer. The incomplete penetrance coupled with the variable age at diagnosis in carriers of the same mutation suggests the existence of genetic and nongenetic modifying factors. In this study, we evaluated the putative role of variants in many candidate modifier genes. Methods: Genotyping data from 15,252 BRCA1 and 8,211 BRCA2 mutation carriers, for known variants (n = 3,248) located within or around 445 candidate genes, were available through the iCOGS custom-designed array. Breast and ovarian cancer association analysis was performed within a retrospective cohort approach. Results: The observed P values of association ranged between 0.005 and 1.000. None of the variants was significantly associated with breast or ovarian cancer risk in either BRCA1 or BRCA2 mutation carriers, after multiple testing adjustments. Conclusion: There is little evidence that any of the evaluated candidate variants act as modifiers of breast and/or ovarian cancer risk in BRCA1 or BRCA2 mutation carriers. Impact: Genome-wide association studies have been more successful at identifying genetic modifiers of BRCA1/2 penetrance than candidate gene studies. Cancer Epidemiol Biomarkers Prev; 24(1); 308–16. ©2014 AACR.

Background and Objective: The premise of effective closed-loop insulin therapy for type 1 diabetes (T1D) relies on the accuracy of continuous interstitial fluid glucose sensing that represents the crucial afferent arm of such a system. An important determinant of sensor accuracy is the physiological time lag of glucose transport from the vascular to the interstitial space. The purpose of current studies was to determine the physiological time lag of glucose transport from the vascular to the abdominal subcutaneous interstitial space in T1D. Method: Four microdialysis catheters were inserted into the abdominal subcutaneous space in 6 T1D subjects under overnight fasted conditions. Plasma glucose was maintained at 113.7 ± 6.3 mg/dl using a continuous intravenous insulin infusion. After sequential intravenous bolus administrations of glucose isotopes, timed plasma and interstitial fluid samples were collected chronologically and analyzed for tracer enrichments. Results: We observed a median (range) time lag of tracer appearance (time to detection) into the interstitial space after intravenous bolus of 6.8 (4.8-9.8) minutes, with all participants having detectable values by 9.8 minutes. Conclusions: We conclude that in the overnight fasted state in T1D adults, the delay of glucose appearance from the vascular to the interstitial space is less than 10 minutes, thereby implying that this minimal physiological time lag should not be a major impediment to the development of an effective closed-loop control system for T1D.

Renal fibrosis is characterized by the excessive accumulation of extracellular matrix (ECM) proteins such as type I collagen, fibronectin, and by the increased expression of PAI-1. This study evaluated the anti-fibrotic effect of bee venom and its major compounds (melittin and apamin) on TGF-β-induced pro-fibrotic gene expression. Bee venom and melittin significantly suppressed type I collagen, fibronectin, and PAI-1 protein expression in the TGF-β-treated kidney fibroblast. However, apamin only inhibited the expression of fibronectin and type I collagen. These results indicated that the inhibitory effects of bee venom on TGF-β-induced pro-fibrotic gene expression are caused by melittin. Moreover, we attempted to elucidate mechanisms underlying the anti-fibrotic effect of melittin. Melittin dramatically inhibited the phosphorylation of TGFβRII and Smad2/3. Also, melittin inhibited the phosphorylation of ERK1/2 and JNK, but not the phosphorylation of PI3K, Akt, and p38. These results suggested that melittin inhibits TGF-β-induced pro-fibrotic genes expression through the suppression of TGFβR-Smad2/3, ERK1/2, and JNK phosphorylation, and melittin can be used as a clinical drug for the treatment of fibrosis associated with renal diseases.

Abstract Tumor infiltrating regulatory T cells (Tregs) appear to play a role in survival in a number of solid tumors, including ovarian cancer. We assessed genetic variation via tag SNPs (N=749) in 25 Treg associated genes (CD28, CTLA4, FOXP3, IDO1, IL10, IL10RA, IL15, 1L17RA, IL23A, IL23R, IL2RA, IL6, IL6R, IL8, LGALS1, LGALS9, MAP3K8, STAT5A, STAT5B, TGFB1, TGFB2, TGFB3, TGFBR1, TGRBR2, and TGFBR3) in relation to ovarian cancer survival. SNPs were selected based on r2 ≥ 0.8, MAF ≥ 0.05, 5 kb upstream and downstream from the gene. We had SNP and outcome data for ovarian cancer from 10,084 combined ovarian cancer cases, including 5,248 high grade serous, 1,452 endometrioid, 661 mucinous, and 795 clear cell cases of European descent across multiple studies from the Ovarian Cancer Association Consortium (OCAC). Cox proportional hazards regression modeling was used to estimate per-allele hazard ratios (HRs) and 95% confidence intervals (CIs) for associations with overall survival, adjusting for age at diagnosis, population substructure PCs, study site, histology (for the all case analysis), tumor stage, tumor grade and oral contraceptive use. The strongest associations were found for endometrioid histologic subtype and IL2RA SNPs (maximum r2=0.67) rs11256497 [HR=1.42, 95% CI: 1.22-1.64; p=5.7 x 10−6], rs791587 [HR=1.36, 95% CI: 1.17-1.57; p=6.2 x 10−5], rs2476491 [HR=1.40, 95% CI: 1.19-1.64; p=5.6 x 10−5], and rs10795763 [HR=1.35, 95% CI: 1.17-1.57; p=7.9 x 10−5], as well as clear cell ovarian cancer and CTLA4 SNP rs231775 [HR=0.67, 95% CI: 0.54-0.82; p=9.3 x 10−5]. No other associations were observed at p<1 x 10−4. Overall, this study provided evidence that variation in genes related to Tregs, particularly IL2RA and CTLA4, influence ovarian cancer survival. Citation Format: Bridget Charbonneau, Keith Knutson, Robert A. Vierkant, Julie M. Cunningham, Zachary C. Fogarty, Kimberly R. Kalli, Matthew J. Maurer, Ann L. Oberg, Brooke L. Fridley, Claudia C. Preston, Paul D.P. Pharoah, Susan J. Ramus, Catherine M. Phelan, Kunle Odunsi, Kirsten Moysich, Ellen L. Goode. Polymorphisms in regulatory T cell related genes and ovarian cancer survival. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4844. doi:10.1158/1538-7445.AM2013-4844

Abstract Background: Autophagy and apoptosis regulate cancer cell viability in response to cytotoxic stress; however, the functional relationship between these processes is unclear. During autophagy, the multifunctional p62/sequestosome 1 protein shuttles ubiquitinated proteins to the lysosome. Previously, we found that ectopic p62 can promote chemotherapy-induced apoptosis. Since Bcl-2 can regulate both autophagy and apoptosis, we determined whether ABT-263-induced apoptosis is regulated by p62. Methods: Human colorectal cancer cell lines (HCT116, DLD1) were incubated with ABT-263 (0-2 μM) and caspase cleavage (immunoblotting), caspase-8 activation (luminescence), apoptosis (annexin V labeling), and autophagy (localization of GFP-LC3 by confocal microscopy) were analyzed. Caspase-8 was suppressed by siRNA or using caspase-8-deficient Jurkat cells. P62 mutants were generated by site-directed mutagenesis. Caspase-8 self aggregation and colocalization with p62 were studied in cells with lentiviral mCherry-p62, transfected with a non-cleavable caspase-8 fused with fluorescent Venus proteins (BiFC). Results: We demonstrate that ABT-263 induces autophagy and a caspase-8-mediated apoptosis, shown using caspase-8 siRNA or caspase-8-deficient cells. Regulation of this process by p62 was demonstrated by the ability of ectopic p62 expression to enhance apoptosis and caspase-8 activation that were disrupted by mutations at p62 functional domains. In contrast, p62 shRNA was shown to attenuate ABT-263-induced apoptosis. ABT-263 treatment enhanced binding between caspase-8 and p62, and triggered caspase-8 self aggregation that colocalized with p62, shown by Biomolecular Fluorescence Complementation (BiFC) assay using confocal microscopy. Consistent with ectopic p62, accumulation of p62 by the lysosomal autophagy inhibitors, chloroquine or bafilomycin A1, enhanced ABT-263-mediated caspase cleavage. Conclusion: p62 can regulate caspase-8 self aggregation/activation by ABT-263 to enable crosstalk between autophagy and apoptosis. Citation Format: Shengbing Huang, Jae Myung Park, Chunrong Yu, Frank A. Sinicrope. p62/sequestosome 1 regulates caspase-8 activation by the Bcl-2 antagonist ABT-263 to enable crosstalk between autophagy and apoptosis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1733. doi:10.1158/1538-7445.AM2013-1733

Abstract BACKGROUND: Breast cancer affects thousands of women each year. Epithelial to Mesenchymal transition (EMT) has been associated with increased metastatic potential of cancer cells as well as resistance to chemotherapy. Predicatively, presence of EMT leads to worse prognosis in patients with breast cancer. We have recently showed that Aurora-A plays a key role in development of EMT and increased ability of breast cancer cells for self renewal. Therefore we hypothesized that inhibition of Aurora-A in breast cancer cells will lead to increased sensitivity to chemotherapy. RESULTS: Increased Aurora-A expression, as assessed by IHC staining, in patients with locally advanced disease was associated with worse prognosis. We show that in ER+ cell line, MCF7, activating MAPK pathway through overexpression of Raf1 leads to increase in Aurora-A activity. These cells have decreased sensitivity to treatment with paclitaxel when compared to untransfected cells in MTT assays. This effect is even more exacerbated with over-expression of Aurora-A. The sensitivity to paclitaxel was restored with inhibition of Aurora-A by specific inhibitor, Alisertib. This was further explored in triple negative (MDA-MB-231) or Her-2/neu expressing (SUM149) cell lines. These cells express higher levels of Aurora-A. Inhibition of Aurora-A activity in combination with paclitaxel was superior when compared to either therapy alone. Similar effect was seen with use of anthracyclines. Inhibition of Aurora-A resulted in decreased SMAD5 expression as well as decreased Akt phosphorylation. Current studies are looking at a role of Aurora-A in activating SMAD5 and its role in resistance to chemotherapy. In vivo experiments evaluating combination therapies in breast cancer animal model are ongoing. CONCLUSIONS: Inhibition of Aurora-A by a specific inhibitor, MLN8237, resulted in decreased SMAD5 expression and increased effectiveness of chemotherapeutic agents in breast cancer cells. These results contribute to better understanding of signaling pathways involved in resistance of breast cancer cells to chemotherapy. This knowledge could be very useful in developing more effective treatments for breast cancer patients in neo-adjuvant, adjuvant and metastatic settings. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-09-07.