Jennifer Permuth-Wey

Epidemiology of ovarian cancer.

Ovarian cancer represents the sixth most commonly diagnosed cancer among women in the world, and causes more deaths per year than any other cancer of the female reproductive system. Despite the high incidence and mortality rates, the etiology of this disease is poorly understood. Established risk factors for ovarian cancer include age and having a family history of the disease, while protective factors include increasing parity, oral contraceptive use, and oophorectomy. Lactation, incomplete pregnancies, and surgeries such as hysterectomy and tubal ligation may confer a weak protective effect against ovarian cancer. Infertility may contribute to ovarian cancer risk among nulliparous women. Other possible risk factors for ovarian cancer include postmenopausal hormone-replacement therapy and lifestyle factors such as cigarette smoking and alcohol consumption. Many of the causes of ovarian cancer are yet to be identified. Additional research is needed to better understand the etiology of this deadly disease.

Upregulation of miRNA-155 promotes tumour angiogenesis by targeting VHL and is associated with poor prognosis and triple-negative breast cancer

MicroRNA-155 (miR-155) is frequently upregulated in various types of human cancer; however, its role in cancer angiogenesis remains unknown. Here, we demonstrate the role of miR-155 in angiogenesis through targeting von Hippel-Lindau (VHL) tumour suppressor in breast cancer. Ectopic expression of miR-155 induced whereas knockdown of miR-155 inhibited human umbilical vein endothelial cell network formation, proliferation, invasion and migration. Furthermore, mammary fat pad xenotransplantation of ectopically expressed miR-155 resulted in extensive angiogenesis, proliferation, tumour necrosis and recruitment of pro-inflammatory cells such as tumour-associated macrophages. Expression of VHL abrogated these miR-155 effects. Moreover, miR-155 expression inversely correlates with VHL expression level and is associated with late-stage, lymph node metastasis and poor prognosis, as well as triple-negative tumour in breast cancer. These findings indicate that miR-155 has a pivotal role in tumour angiogenesis by downregulation of VHL, and provide a basis for miR-155-expressing tumours to embody an aggressive malignant phenotype, and therefore miR-155 is an important therapeutic target in breast cancer.

MicroRNA MiR-214 regulates ovarian cancer cell stemness by targeting p53/Nanog.

Background: Ovarian cancer stem cells (OCSC) play a critical role in chemoresistance and relapse. Results: Expression of miR-214 induces, whereas knockdown of miR-214 decreases, OCSC and Nanog. MiR-214 targets p53, a repressor of Nanog. Conclusion: miR-214 targets p53 to induce OCSC and Nanog. Significance: MiR-214 is a target for OCSC. Previous studies have shown aberrant expression of miR-214 in human malignancy. Elevated miR-214 is associated with chemoresistance and metastasis. In this study, we identified miR-214 regulation of ovarian cancer stem cell (OCSC) properties by targeting p53/Nanog axis. Enforcing expression of miR-214 increases, whereas knockdown of miR-214 decreases, OCSC population and self-renewal as well as the Nanog level preferentially in wild-type p53 cell lines. Furthermore, we found that p53 is directly repressed by miR-214 and that miR-214 regulates Nanog through p53. Expression of p53 abrogated miR-214-induced OCSC properties. These data suggest the critical role of miR-214 in OCSC via regulation of the p53-Nanog axis and miR-214 as a therapeutic target for ovarian cancer.

LIN28B Polymorphisms Influence Susceptibility to Epithelial Ovarian Cancer

Defective microRNA (miRNA) biogenesis contributes to the development and progression of epithelial ovarian cancer (EOC). In this study, we examined the hypothesis that single nucleotide polymorphisms (SNP) in miRNA biogenesis genes may influence EOC risk. In an initial investigation, 318 SNPs in 18 genes were evaluated among 1,815 EOC cases and 1,900 controls, followed up by a replicative joint meta-analysis of data from an additional 2,172 cases and 3,052 controls. Of 23 SNPs from 9 genes associated with risk (empirical P < 0.05) in the initial investigation, the meta-analysis replicated 6 SNPs from the DROSHA, FMR1, LIN28, and LIN28B genes, including rs12194974 (G>A), an SNP in a putative transcription factor binding site in the LIN28B promoter region (summary OR = 0.90, 95% CI: 0.82-0.98; P = 0.015) which has been recently implicated in age of menarche and other phenotypes. Consistent with reports that LIN28B overexpression in EOC contributes to tumorigenesis by repressing tumor suppressor let-7 expression, we provide data from luciferase reporter assays and quantitative RT-PCR to suggest that the inverse association among rs12194974 A allele carriers may be because of reduced LIN28B expression. Our findings suggest that variants in LIN28B and possibly other miRNA biogenesis genes may influence EOC susceptibility.

Long Non-coding RNAs (LncRNA) Regulated by Transforming Growth Factor (TGF) β: LncRNA-HIT-MEDIATED TGFβ-INDUCED EPITHELIAL TO MESENCHYMAL TRANSITION IN MAMMARY EPITHELIA*

Background: Long noncoding RNAs (LncRNA) are emerging as key regulators in various biological processes. However, their role in epithelial-to-mesenchymal transition (EMT) remains elusive. Results: A subset of lncRNAs are dysregulated upon transforming growth factor (TGF) β-induced EMT, and lncRNA-HIT mediates this process. Conclusion: LncRNAs such as lncRNA-HIT ((HOXA transcript induced by TGFβ) play a pivotal role in EMT and breast cancer progression. Significance: Here we profiled lncRNAs in TGFβ-induced EMT and identified a novel conserved lncRNA-HIT. Long noncoding RNAs (lncRNAs) are emerging as key regulators in various biological processes. Epithelial-to-mesenchymal transition (EMT) is a developmental process hijacked by tumor cells to depart from the primary tumor site, invade surrounding tissue, and establish distant metastases. Transforming growth factor β (TGFβ) signaling has been shown to be a major inducer of EMT and to facilitate breast cancer metastasis. However, the role of lncRNAs in this process remains largely unknown. Here we report a genome-wide lncRNA profile in mouse mammary epithelial NMuMG cells upon TGFβ induction of EMT. Among 10,802 lncRNAs profiled, over 600 were up-regulated and down-regulated during the EMT, respectively. Furthermore, we identify that lncRNA-HIT (HOXA transcript induced by TGFβ) mediates TGFβ function, i.e. depletion of lncRNA-HIT inhibits TGFβ-induced migration, invasion, and EMT in NMuMG. LncRNA-HIT is also significantly elevated in the highly metastatic 4T1 cells. Knockdown of lncRNA-HIT in 4T1 results in decrease of cell migration, invasion, tumor growth, and metastasis. E-cadherin was identified as a major target of lncRNA-HIT. Moreover, lncRNA-HIT is conserved in humans and elevated expression associates with more invasive human primary breast carcinoma. Collectively, these data suggest that a subset of lncRNAs such as lncRNA-HIT play a significant role in regulation of EMT and breast cancer invasion and metastasis, and could be potential therapeutic targets in breast cancers.

A functional variant in HOXA11-AS, a novel long non-coding RNA, inhibits the oncogenic phenotype of epithelial ovarian cancer

The homeobox A (HOXA) region of protein-coding genes impacts female reproductive system embryogenesis and ovarian carcinogenesis. The 5-prime end of HOXA includes three long non-coding RNAs (lncRNAs) (HOXA10-AS, HOXA11-AS, and HOTTIP) that are underexplored in epithelial ovarian cancer (EOC). We evaluated whether common genetic variants in these lncRNAs are associated with EOC risk and/or have functional roles in EOC development. Using genome-wide association study data from 1,201 serous EOC cases and 2,009 controls, an exonic variant within HOXA11-AS, rs17427875 (A>T), was marginally associated with reduced serous EOC risk (OR = 0.88 (95% CI: 0.78-1.01, p = 0.06). Functional studies of ectopic expression of HOXA11-AS minor allele T in EOC cells showed decreased survival, proliferation, migration, and invasion compared to common allele A expression. Additionally, stable expression of HOXA11-AS minor allele T reduced primary tumor growth in mouse xenograft models to a greater extent than common allele A. Furthermore, HOXA11-AS expression levels were significantly lower in human EOC tumors than normal ovarian tissues (p < 0.05), suggesting that HOXA11-AS has a tumor suppressor function in EOC which may be enhanced by the T allele. These findings demonstrate for the first time a role for HOXA11-AS in EOC with effects that could be modified by germline variants.

Inherited Variants in Mitochondrial Biogenesis Genes May Influence Epithelial Ovarian Cancer Risk

Background: Mitochondria contribute to oxidative stress, a phenomenon implicated in ovarian carcinogenesis. We hypothesized that inherited variants in mitochondrial-related genes influence epithelial ovarian cancer (EOC) susceptibility. Methods: Through a multicenter study of 1,815 Caucasian EOC cases and 1,900 controls, we investigated associations between EOC risk and 128 single nucleotide polymorphisms (SNPs) from 22 genes/regions within the mitochondrial genome (mtDNA) and 2,839 nuclear-encoded SNPs localized to 138 genes involved in mitochondrial biogenesis (BIO, n = 35), steroid hormone metabolism (HOR, n = 13), and oxidative phosphorylation (OXP, n = 90) pathways. Unconditional logistic regression was used to estimate OR and 95% CI between genotype and case status. Overall significance of each gene and pathway was evaluated by using Fishers method to combine SNP-level evidence. At the SNP level, we investigated whether lifetime ovulation, hormone replacement therapy (HRT), and cigarette smoking were confounders or modifiers of associations. Results: Interindividual variation involving BIO was most strongly associated with EOC risk (empirical P = 0.050), especially for NRF1, MTERF, PPARGC1A, ESRRA, and CAMK2D. Several SNP-level associations strengthened after adjustment for nongenetic factors, particularly for MTERF. Statistical interactions with cigarette smoking and HRT use were observed with MTERF and CAMK2D SNPs, respectively. Overall variation within mtDNA, HOR, and OXP was not statistically significant (empirical P > 0.10). Conclusion: We provide novel evidence to suggest that variants in mitochondrial biogenesis genes may influence EOC susceptibility. Impact: A deeper understanding of the complex mechanisms implicated in mitochondrial biogenesis and oxidative stress may aid in developing strategies to reduce morbidity and mortality from EOC. Cancer Epidemiol Biomarkers Prev; 20(6); 1131–45. ©2011 AACR.

Genetic predictors of fatigue in prostate cancer patients treated with androgen deprivation therapy: Preliminary findings

BACKGROUND Fatigue is a common and distressing side effect of androgen deprivation therapy (ADT) for prostate cancer. The goal of the current study was to examine the relationship between changes in fatigue following initiation of ADT and single nucleotide polymorphisms (SNPs) in three pro-inflammatory cytokine genes: interleukin-1 beta (IL1B), interleukin-6 (IL6), and tumor necrosis factor alpha (TNFA). METHODS As part of a larger study, men with prostate cancer (n = 53) were recruited prior to initiation of ADT. Fatigue was assessed at recruitment and 6 months after initiation of ADT. DNA was extracted from blood drawn at baseline. RESULTS Patients with the IL6-174 (rs1800795) G/C or C/C genotype displayed greater increases in fatigue intrusiveness, frequency, and duration than the G/G genotype (p values ≤ 0.05), although inclusion of age, race, and baseline depressive symptomatology in the model attenuated these relationships (p values ≤ 0.09). Patients with the TNFA-308 (rs1800629) G/A genotype showed greater increases in fatigue severity than the G/G genotype (p = 0.02). IL1B-511 (rs16944) genotype did not significantly predict changes in fatigue (p values >0.46). Patients with higher numbers of variants displayed greater increases in fatigue duration and interference (p values ≤ 0.02) than patients with lower numbers of variants. CONCLUSIONS Prostate cancer patients treated with ADT who carry variant alleles of the IL6 and TNFA genes are susceptible to heightened fatigue. These preliminary data lend support for the role of genetic variation in the development of cancer-related fatigue secondary to ADT. Findings are relevant to attempts to develop personalized approaches to cancer treatment.

A Genome-Wide Investigation of MicroRNA Expression Identifies Biologically-Meaningful MicroRNAs That Distinguish between High-Risk and Low-Risk Intraductal Papillary Mucinous Neoplasms of the Pancreas

Background Intraductal papillary mucinous neoplasms (IPMNs) are pancreatic ductal adenocarcinoma (PDAC) precursors. Differentiating between high-risk IPMNs that warrant surgical resection and low-risk IPMNs that can be monitored is a significant clinical problem, and we sought to discover a panel of mi(cro)RNAs that accurately classify IPMN risk status. Methodology/Principal Findings In a discovery phase, genome-wide miRNA expression profiling was performed on 28 surgically-resected, pathologically-confirmed IPMNs (19 high-risk, 9 low-risk) using Taqman MicroRNA Arrays. A validation phase was performed in 21 independent IPMNs (13 high-risk, 8 low-risk). We also explored associations between miRNA expression level and various clinical and pathological factors and examined genes and pathways regulated by the identified miRNAs by integrating data from bioinformatic analyses and microarray analysis of miRNA gene targets. Six miRNAs (miR-100, miR-99b, miR-99a, miR-342-3p, miR-126, miR-130a) were down-regulated in high-risk versus low-risk IPMNs and distinguished between groups (P<10−3, area underneath the curve (AUC) = 87%). The same trend was observed in the validation phase (AUC = 74%). Low miR-99b expression was associated with main pancreatic duct involvement (P = 0.021), and serum albumin levels were positively correlated with miR-99a (r = 0.52, P = 0.004) and miR-100 expression (r = 0.49, P = 0.008). Literature, validated miRNA:target gene interactions, and pathway enrichment analysis supported the candidate miRNAs as tumor suppressors and regulators of PDAC development. Microarray analysis revealed that oncogenic targets of miR-130a (ATG2B, MEOX2), miR-342-3p (DNMT1), and miR-126 (IRS-1) were up-regulated in high- versus low-risk IPMNs (P<0.10). Conclusions This pilot study highlights miRNAs that may aid in preoperative risk stratification of IPMNs and provides novel insights into miRNA-mediated progression to pancreatic malignancy. The miRNAs identified here and in other recent investigations warrant evaluation in biofluids in a well-powered prospective cohort of individuals newly-diagnosed with IPMNs and other pancreatic cysts and those at increased genetic risk for these lesions.

Financial Remuneration for Clinical and Behavioral Research Participation: Ethical and Practical Considerations

PURPOSE Although the practice of providing payment to clinical research participants has been ongoing for more than a century, it remains an ethically controversial topic among members of the research community. The aims of this commentary are to summarize ethical and practical considerations regarding financial remuneration of research participants and to make recommendations for researchers contemplating this practice. METHODS A PubMed search was conducted to explore the ethical implications surrounding financial remuneration and review the body of empiric data on this topic. RESULTS Financial remuneration is perceived to be ethically acceptable by many researchers and research participants and can be helpful in the recruitment process. It is recommended that when investigators are contemplating whether to offer payment to research participants, they should consider the nature of the study and the potential benefits and risks to the participants, institutional or organizational guidelines, and cultural and societal norms specific to the population being studied. CONCLUSIONS Financial remuneration has the ability to serve as a sign of appreciation for the contributions of research participants and a way to facilitate clinical and behavioral research.