Citations

Abstract Endoglin, a 180-kDa disulfide-linked homodimeric transmembrane receptor protein mostly expressed in tumor-associated endothelial cells, is an endogenous binding partner of GAIP-interacting protein, C terminus (GIPC). Endoglin functions as a coreceptor of TβRII that binds TGFβ and is important for vascular development, and consequently has become a compelling target for antiangiogenic therapies. A few recent studies in gastrointestinal stromal tumor (GIST), breast cancer, and ovarian cancer, however, suggest that endoglin is upregulated in tumor cells and is associated with poor prognosis. These findings indicate a broader role of endoglin in tumor biology, beyond angiogenic effects. The goal of our current study is to evaluate the effects of targeting endoglin in pancreatic cancer both in vitro and in vivo. We analyzed the antiproliferative effect of both RNAi-based and peptide ligand-based inhibition of endoglin in pancreatic cancer cell lines, the latter yielding a GIPC PDZ domain-targeting lipopeptide with notable antiproliferative activity. We further demonstrated that endoglin inhibition induced a differentiation phenotype in the pancreatic cancer cells and sensitized them against conventional chemotherapeutic drug gemcitabine. Most importantly, we have demonstrated the antitumor effect of both RNAi-based and competitive inhibitor–based blocking of endoglin in pancreatic cancer xenograft models in vivo. To our knowledge, this is the first report exploring the effect of targeting endoglin in pancreatic cancer cells. Mol Cancer Ther; 13(10); 2264–75. ©2014 AACR.

AbstractObjective The high level of stress associated with caring for others with medical conditions has been recognized for some time. Reducing caregiver stress can improve caregiver quality of life as well as improve the care they provide to loved ones. This systematic review assesses the effectiveness of internet-based interventions to decrease caregiver stress.Materials and methods A comprehensive literature search of Ovid MEDLINE (1946–2013), Embase (1988–2013), PsycINFO (1987–2013), and CINAHL was conducted using terms related to caregiver and internet-based interventions. Internet-based interventions involving informal caregivers in an open-label or randomized controlled trial setting were included. A pair of raters independently reviewed all published abstracts. Data regarding participants, interventions, and outcomes were extracted and, for randomized trials, methodology quality was also reviewed.Results Eight open-label trials met the review criteria: three showed positive benefit in reducing caregiver stress, four were partially positive (some outcomes positive, others negative), and one was a negative study. Sixteen randomized trials met the review criteria: six showed positive benefit, five were partially positive, and five were negative. There were no clear patterns as to the variables (such as study duration and complexity of intervention) associated with better outcomes, although earlier studies typically had more negative outcomes.Discussion Internet-based interventions were mostly effective in reducing aspects of caregiver stress and improving their well-being. Further studies to assess outcomes for caregivers and their recipients’ health, different technology delivery methods, and the cost of such interventions are needed.

Objective Previous studies have suggested that statin pretreatment prevents contrast-induced nephropathy (CIN). However, single randomised trials are limited in their number of patients. This meta-analysis aims to assess the role of statin use in CIN prevention, as well as to determine patient subgroups that will benefit from statin pre-treatment. Methodology We searched PubMed, EMBASE, Web of science and the Cochrane Central Register of Controlled Trials databases for randomised controlled trials (RCT) comparing statin pretreatment versus placebo for preventing CIN. Our main outcome was the risk of CIN within 1–5 days after contrast administration. Results Data analysed from nine randomised studies with a total of 5143 patients, where 2559 received statins and 2584 received placebo, showed that statin pretreatment was associated with significant reduction in risk of CIN (MH-RR=0.47, 95% CI 0.34 to 0.64, Z=4.49, p<0.00001). This beneficial effect of statin was also seen in patients with baseline renal impairment (MH-RR=0.46, 95% CI 0.29 to 0.72, p=0.0008) and also those who were cotreated with NAC (MH-RR=0.46, 95% CI 0.25 to 0.83, p=0.01). Conclusions Statin pretreatment leads to significant reduction in CIN, and should be strongly considered in all patients who are planned for diagnostic and interventional procedures involving contrast-media administration.

Abstract Synthetic lethal interactions enable a novel approach for discovering specific genetic vulnerabilities in cancer cells that can be exploited for the development of therapeutics. This concept has recently been exploited in the development of PARP inhibitors as novel chemotherapeutics for breast cancer. While PARP is not essential in normal cells, BRCA mutant cells are dependent on it for their survival. This led to the successful treatment of BRCA mutant tumors of the breast, ovary, and prostate with the oral PARP inhibitor, olaparib. Therapeutic strategies based on such synthetic-lethal (SL) interactions can enable drug targeting of cancer-specific alterations for otherwise undruggable tumor suppressors. Large-scale analyses of genetic interaction networks in model organisms like yeast suggest that disease-specific networks should not only give rise to destructive phenotypes (e.g. uncontrolled cell growth), but will also present unique vulnerabilities that can be exploited for novel therapies. Despite successes in model organisms such as yeast, discovering synthetic lethal interactions on a large scale in human cells remains a significant challenge. We have used a combination of computational and experimental approach whereby yeast interactions between human orthologs are filtered by cancer association and prioritized by genomic features, and candidates from the prioritized list are then validated in human cell lines using an RNA interference approach. As a proof of principle, we utilized this approach to discover two previously unknown synthetic lethal/sick interactions, one between SMARCB1 (yeast SNF5) and PSMA4 (yeast PRE9), and another between ASPSCR1 (yeast UBX4) and PSMC2 (yeast RPT1) based on shRNA double knock-down in normal human fibroblast cells. These interactions suggest potentially new therapeutic targets for SMARCB1 and ASPSCR1 mutated cancers, and more broadly, illustrate the potential of this cross-species approach. Citation Format: Michael K. Asiedu, Raamesh Deshpande, Mitchell Klebig, Shari Sutor, Elena Kuzmin, Jeff Piotrowski, Seung Ho Shin, Michael Costanzo, Charles Boone, Dennis A. Wigle, Chad L Myers. A comparative genomic approach for identifying synthetic lethal interactions in human cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-234. doi:10.1158/1538-7445.AM2013-LB-234

Abstract Ovarian cancer is the fifth leading cause of cancer death among women in the United States. Despite advances in treatment for other cancers, ovarian cancer patient prognosis has not improved significantly since the advent of platinum-based chemotherapy. It is a highly heterogeneous disease with at least four distinct histological subtypes: serous, mucinous, endometrioid, and clear cell. However, no subtype- or biomarker-specific therapies are approved for ovarian cancer. Identifying targeted therapies is crucial to improving clinical outcomes. Specific therapies will likely vary based on tumor histology and biomarkers. Expression of estrogen receptor alpha (ER) is a well established biomarker of response to endocrine therapies in breast cancer. Despite the success of anti-estrogen therapies in treating breast cancer, little attention has been given to their potential in ovarian cancer. However, epidemiologic studies show that approximately 70% of epithelial ovarian tumors express ER, particularly serous and endometrioid subtypes, and that estrogen plays a role in ovarian cancer etiology. Further, clinical data suggest that a subset of ovarian cancer patients can be successfully treated with endocrine therapy. We hypothesize that some ovarian tumors require estrogen for growth and that predictive biomarkers will identify patients who will benefit from endocrine therapy. Using cell line models, we examined the response of ovarian cancer cells to estrogen (E2) and anti-estrogens with regard to gene expression and cell proliferation. E2 induces expression of canonical ER target genes (e.g. GREB1) in these cells, suggesting that they are estrogen-responsive. We observe that 4-hydroxytamoxifen and fulvestrant inhibit growth of ovarian cancer cells including the chemo-resistant line PEO4. Gene expression microarray studies identified additional E2-regulated genes in ovarian cancer cells that may be utilized as biomarkers of ER activity. We are expanding our studies to in vivo models (human primary tumor xenografts) to evaluate the role of E2 in driving tumor progression and determine the efficacy of anti-estrogens in treating serous ovarian cancer. There is a critical need for targeted therapies in ovarian cancer. Our studies will determine if endocrine responsiveness correlates with gene expression of specific biomarkers, which may lead to the identification of predictive clinical markers of response to endocrine therapy. Citation Format: Courtney L. Andersen, Matthew J. Sikora, Paul Haluska, Steffi Oesterreich. Identifying biomarkers of estrogen response in models of serous ovarian cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 94. doi:10.1158/1538-7445.AM2013-94

Abstract The Polycomb repressive complex 2 (PRC2) is important for maintenance of stem cell pluripotency and suppression of cell differentiation by promoting histone H3 lysine 27 trimethylation (H3K27me3) and transcriptional repression of differentiation regulatory genes. Here we show that the tumor suppressor protein BRCA1 interacts with EZH2 and other components of PRC2 in mouse embryonic stem (ES) and human breast cancer cells. The BRCA1-binding region in EZH2 overlaps with the non-coding RNA (ncRNA)-binding domain, and BRCA1 expression inhibits the binding of EZH2 to the HOTAIR ncRNA. Decreased expression of BRCA1 causes EZH2 re-targeting genome wide and elevates H3K27me3 levels at PRC2 target loci in both mouse ES and human breast cancer cells. BRCA1 deficiency blocks ES cell differentiation and enhances breast cancer migration and invasion in an EZH2-dependent manner. These results reveal that BRCA1 is a key negative modulator of PRC2 and that loss of BRCA1 inhibits ES cell differentiation and enhances cancer aggressive phenotypes via augmented PRC2 function. Citation Format: Xianzhou Zeng, Shuai Chen, Lan Wang, Haojie Huang. BRCA1 is a negative modulator of the PRC2 complex. [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 5358. doi:10.1158/1538-7445.AM2013-5358

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&lt;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: Variation in mitochondrial genes in cancer cells alters the mitochondrial bioenergetic and biosynthetic state, which mediates cross-talk between mitochondria and the nucleus to modulate many cellular processes. The objective of this study was to comprehensively evaluate mitochondria-nuclear cross-talk in terms of SNP-SNP interactions associated with invasive epithelial ovarian cancer (EOC) risk, which may play an important role in unveiling the underlying mechanism of this complex lethal disease. Methods: Our analyses were based on 1,938 invasive EOC cases and 2,009 controls with greater than 80% European ancestry from five case-control studies genotyped using the Illumina 610quad chip. We evaluated 2,488 SNPs in over 1,500 genes in eight mitochondria-related pathways (apoptosis, oxidation-reduction, epithelial-mesenchymal transition, immunomoduation, transmembrane transport, small GTPases, BRCA1-interactors and circadian rhythm). SNPs with strong linkage disequilibrium of r2 &gt; 0.8 were excluded. We examined 2-way SNP-SNP interactions associated with invasive EOC risk using the two-stage Random Forests plus Multivariate Adaptive Regression Splines (TRM) approach. Bootstrapping was further performed to select important variables and reduce false positive findings. Based on the scree plot using 1,000 bootstrap samples, the factors with more than 4% of bootstrap frequency were defined as significant factors. We then included each identified factors separately in model adjusting for study site and first principal component representing European ancestry. Results: Five significant SNP-SNP interactions were observed: (rs2270799 in IQSEC3 (12p13.33) + rs933305 in CUX2 (12q24.3), (p= 6.3x10−5); rs6063251 in PREX1 (20q13.3) + rs9705 in SLC39A8 (4q22-q24), (p= 3.5x10−5); rs933305 in CUX2 (12q24.3) + rs1712957 in ARHGAP15 (2q22.2-q22.3), (p=4.2x10−7), rs2861828 in SLIT1 (10q23.3-q24) + rs6063251 in PREX1 (20q13.3), (p=2.5x10−7); rs10954593 in SEMA3C (7q21-q31) + rs933305 in CUX2 (12q24.3), (p=2.8x10−3). Four of the five interactions involved SNPs from genes in the small GTPases pathway (IQSEC3; PREX1 (twice) and ARHGAP15). In addition, three of the five interaction pairs involved the CUX2 gene. This gene encodes a protein which contains three CUT domains and a homeodomain, which are DNA-binding motifs. The main mitochondrial SNP-SNP interaction involved the nuclear mitochondria gene SLC39A8. Conclusions: Our results suggest that genetic variation in mitochondrial-related pathways may be associated with invasive EOC risk. These findings highlight important genes/pathways that may interact as a network to influence invasive EOC risk and may generate novel therapeutic targets. External validation will be done using other independent studies for future analyses. Citation Format: Hui-Yi Lin, Ya-Yu Tsai, Y. Ann Chen, Zhihua Chen, Xiaotao Qu, Ellen L. Goode, Joellen Schildkraut, Edwin Iversen, Steven A. Narod, Thomas A. Sellers, Catherine M. Phelan. SNP-SNP interactions in mitochondria-related pathways are associated with invasive Epithelial Ovarian Cancer (EOC) risk . [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 4839. doi:10.1158/1538-7445.AM2013-4839

Abstract Background: Genetic and environmental factors influence colorectal cancer (CRC) risk. Previous studies have provided additional etiologic insight by examining multiplicative gene-environment interactions for individual susceptibility loci. However, individual loci confer only modest risks, which may limit statistical power and clinical significance. A genetic risk score comprising known CRC loci may provide a more comprehensive assessment of risk. Further, there is a paucity of data on the role of additive gene-environment interactions, which may have greater public health implications than multiplicative interactions. We thus evaluated both additive and multiplicative interactions between a genetic risk score and 15 key environmental factors on risk of CRC. Methods: We conducted an analysis of 10,491 CRC cases and 10,725 controls of European ancestry in 7 cohort and 6 case-control studies participating in the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO) or Colon Cancer Family Registry (CCFR). To provide a global measure of genetic predisposition, information across multiple risk variants was combined by calculating a genetic risk score based on 24 polymorphisms near 21 genetic loci identified in previous genome-wide association studies. For the genetic score and environmental factors, the reference category corresponded to that associated with lower CRC risk. We tested for additive interactions by estimating relative excess risk due to interactions (RERIs) using logistic regression; for multiplicative interactions we used an empirical-Bayes approach. Nominal P values ≤ 0.05 were considered statistically significant. Results: After adjustment for age, sex, center, study, principal components, and total energy, as appropriate, we observed super-additive gene-environment interactions for CRC risk between the genetic risk score and body mass index (RERI=0.15; 95% CI: 0.00-0.31), ever smoking (RERI=0.14; 95% CI: 0.00-0.28), pack-years of smoking (RERI=0.23; 95% CI: 0.05-0.41), postmenopausal hormone therapy use (RERI=0.38; 95% CI: 0.17-0.59), and intake of processed meat (RERI=0.23; 95% CI: 0.06-0.40). Of the 15 environmental risk factors, 12 showed RERIs &gt; 0 – suggesting an overall trend toward super-additive interactions for these factors. In addition, we observed evidence of sub-multiplicative interactions for use of aspirin and non-steroidal anti-inflammatory drugs. There were no other statistically significant multiplicative interactions. Conclusions: We observed evidence for super-additive effects of genetic predisposition and environmental risk factors on risk of CRC. Our findings suggest that certain environmental risk factors have stronger effects on absolute risk among individuals with higher genetic risk of CRC. If confirmed in future studies, these results may have implications for targeted prevention strategies. Citation Format: Mengmeng Du, Sonja I. Berndt, Hermann Brenner, Bette J. Caan, Peter T. Campbell, Graham Casey, Andrew Chan, Jenny Chang-Claude, Stephen J. Chanock, Nilanjan Chatterjee, David V. Conti, David Duggan, Jane C. Figueiredo, Steven Gallinger, Jian Gong, Robert W. Haile, Tabitha A. Harrison, Richard B. Hayes, Michael Hoffmeister, John L. Hopper, Li Hsu, Thomas J. Hudson, Carolyn M. Hutter, Eric J. Jacobs, Mark A. Jenkins, Shuo Jiao, Laurence N. Kolonel, Peter Kraft, Loic Le Marchand, Mathieu Lemire, Yi Lin, Noralane M. Lindor, Polly A. Newcomb, John D. Potter, Robert E. Schoen, Fredrick R. Schumacher, Daniela Seminara, Martha L. Slattery, Stephen N. Thibodeau, Cornelia M. Ulrich, Aung Ko Win, Emily White, Brent W. Zanke, Ulrike Peters. Additive and multiplicative gene-environment interactions for colorectal cancer risk. [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 4831. doi:10.1158/1538-7445.AM2013-4831

Abstract In searching for a role for genetic variation in susceptibility to lung cancer, we postulated that miRNA modulating SNPs within smoking behavior associated genes, such as the nicotinic acetylcholine and dopamine receptor families, could modulate susceptibility to tobacco carcinogens and lung cancer risk. Bioinformatic analyses of these gene families identified 5 SNPs predicted to modulate a miRNA binding site. We assessed these SNPs in the National Cancer Institute-MD case-control study (European American [EA] & African Americans [AA] n=1,438). rs686 in DRD1 (dopamine receptor D1) was associated with a reduced risk of lung cancer after adjustment for age, gender and race (OR 0.63, 95% C.I. 0.47-0.85; P=0.002). As DRD1 mediates dopamine signaling following nicotine exposure, we reasoned that the rs686 variant associates with lung cancer risk via modulation of the nicotine reward pathway. However, adjustment for smoking both in terms of smoking status and pack-years did not significantly modulate the association (OR 0.57, 95% C.I. 0.40-0.81, P=0002). In addition, age at smoking initiation, pack-years of smoking and levels of urinary nicotine metabolites (cotinine and hydroxycotinine) did not vary across rs686 genotypes. Moreover, in an analysis of a never smoking cohort from Mayo Clinic, rs686 was also associated with a reduced risk of lung cancer (OR 0.77, 95% C.I. 0.62-0.97; P=0.027; n=629) (pooled analysis OR 0.61, 95% C.I. 0.47-0.78; P&lt;0.0001; n=2,067). Intriguingly, the association between rs686 and lung cancer risk was only observed in subjects exposed to tobacco smoke during childhood (EA smokers: [OR 0.63, 95% C.I. 0.45-0.88; P=0.007] EA never smokers [OR 0.64, 95% C.I. 0.49-0.85; P=0.002] AA smokers OR 0.31, 95% C.I. 0.11-0.89; P=0.029) (model adjusted as above and for education, adult-second-hand smoke exposure). To further explore a relationship between tobacco and DRD1, we exposed lung cancer cell lines to increasing doses of nicotine and observed a significant increase in DRD1 expression (P=0.009). As DRD1 lies within a CpG island, we are currently testing if this regulation occurs via epigenetic modulation of the DRD1 promoter. While a direct role for DRD1 in lung cancer has not previously been reported, a recent report linked DRD to the cancer stem cell hypothesis. Indeed, our work demonstrates that DRD1 is significantly upregulated in lung cells with cancer stem-like properties. Furthermore, miR-296, predicted to bind to variant rs686 allele, is increased in paired lung cancer tissues (P=0.0003), thus linking a decrease in DRD1 with reduced lung cancer risk. Collectively, our work suggests a novel lung cancer pathway whereby rs686 in DRD1 counteracts the increase in DRD1 imposed by exposure to tobacco smoke in both current and never smokers. Furthermore, it hints at a novel role for the dopamine receptor/signaling pathway in lung carcinogenesis. Citation Format: Brid M. Ryan, Ana I. Robles, Andrew C. McClary, Elise Bowman, Kirsi Vahakangas, Susan Olivo-Marston, Ping Yang, Jin Jen, Curtis C. Harris. Interaction between DRD1 and childhood exposure to environmental tobacco smoke modulates lung cancer risk in smokers and never smokers. [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 4581. doi:10.1158/1538-7445.AM2013-4581