Karen Smith-McCune

The RAB25 small GTPase determines aggressiveness of ovarian and breast cancers

High-density array comparative genomic hybridization (CGH) showed amplification of chromosome 1q22 centered on the RAB25 small GTPase, which is implicated in apical vesicle trafficking, in approximately half of ovarian and breast cancers. RAB25 mRNA levels were selectively increased in stage III and IV serous epithelial ovarian cancers compared to other genes within the amplified region, implicating RAB25 as a driving event in the development of the amplicon. Increased DNA copy number or RNA level of RAB25 was associated with markedly decreased disease-free survival or overall survival in ovarian and breast cancers, respectively. Forced expression of RAB25 markedly increased anchorage-dependent and anchorage-independent cell proliferation, prevented apoptosis and anoikis, including that induced by chemotherapy, and increased aggressiveness of cancer cells in vivo. The inhibition of apoptosis was associated with a decrease in expression of the proapoptotic molecules, BAK and BAX, and activation of the antiapoptotic phosphatidylinositol 3 kinase (PI3K) and AKT pathway, providing potential mechanisms for the effects of RAB25 on tumor aggressiveness. Overall, these studies implicate RAB25, and thus the RAB family of small G proteins, in aggressiveness of epithelial cancers.

Patterns of genomic loss of heterozygosity predict homologous recombination repair defects in epithelial ovarian cancer

Background:Defects in BRCA1, BRCA2, and other members of the homologous recombination pathway have potential therapeutic relevance when used to support agents that introduce or exploit double-stranded DNA breaks. This study examines the association between homologous recombination defects and genomic patterns of loss of heterozygosity (LOH).Methods:Ovarian tumours from two independent data sets were characterised for defects in BRCA1, BRCA2, and RAD51C, and LOH profiles were generated. Publically available data were downloaded for a third independent data set. The same analyses were performed on 57 cancer cell lines.Results:Loss of heterozygosity regions of intermediate size were observed more frequently in tumours with defective BRCA1 or BRCA2 (P=10−11). The homologous recombination deficiency (HRD) score was defined as the number of these regions observed in a tumour sample. The association between HRD score and BRCA deficiency was validated in two independent ovarian cancer data sets (P=10−5 and 10−29), and identified breast and pancreatic cell lines with BRCA defects.Conclusion:The HRD score appears capable of detecting homologous recombination defects regardless of aetiology or mechanism. This score could facilitate the use of PARP inhibitors and platinum in breast, ovarian, and other cancers.

The Cationic Properties of SEVI Underlie Its Ability To Enhance Human Immunodeficiency Virus Infection

ABSTRACT Human semen contains peptides capable of forming amyloid fibrils termed semen-derived enhancer of viral infection (SEVI) that can greatly increase human immunodeficiency virus (HIV) infection. While SEVI appears to enhance virion attachment to target cells, its underlying mechanism of action is unknown. We now demonstrate that the intrinsic positive charges of SEVI (pI = 10.21) facilitate virion attachment to and fusion with target cells. A mutant form of SEVI in which lysines and arginines are replaced with alanines retains the ability to form amyloid fibrils but is defective in binding virions and enhancing infection. In addition, the interaction of wild-type SEVI with virions and the ability of these fibrils to increase infection are abrogated in the presence of various polyanionic compounds. These anionic polymers also decrease the enhancement of HIV infection mediated by semen. These findings suggest that SEVI enhances viral infection by serving as a polycationic bridge that neutralizes the negative charge repulsion that exists between HIV virions and target cells. Combinations of agents that neutrale SEVI action and produce HIV virucidal effects are an attractive future direction for microbicide development.

Enhancing tumor-specific uptake of the anticancer drug cisplatin with a copper chelator

Uptake of the anticancer drug cisplatin is mediated by the copper transporter CTR1 in cultured cells. Here we show in human ovarian tumors that low levels of Ctr1 mRNA are associated with poor clinical response to platinum-based therapy. Using a mouse model of human cervical cancer, we demonstrate that combined treatment with a copper chelator and cisplatin increases cisplatin-DNA adduct levels in cancerous but not in normal tissues, impairs angiogenesis, and improves therapeutic efficacy. The copper chelator also enhances the killing of cultured human cervical and ovarian cancer cells with cisplatin. Our results identify the copper transporter as a therapeutic target, which can be manipulated with copper chelating drugs to selectively enhance the benefits of platinum-containing chemotherapeutic agents.

Human papillomavirus infection and increased risk of HIV acquisition. A systematic review and meta-analysis

Objectives:Human papillomavirus (HPV), one of the commonest sexually transmitted infections, may be a cofactor in HIV acquisition. We systematically reviewed the evidence for an association of HPV infection with HIV acquisition in women, heterosexual men and men who have sex with men (MSM). Design:Systematic review and meta-analysis. Methods:Studies meeting inclusion criteria in Pubmed, Embase and conference abstracts up to 29 July 2011 were identified. Random effects meta-analyses were performed to calculate summary hazard ratios (HR). Publication bias and statistical heterogeneity were evaluated and population attributable fractions (PAFs) calculated. Results:Eight articles were included, with previously unpublished data from five authors. Seven studies found an association between prevalent HPV and HIV acquisition. Risk of HIV acquisition in women doubled with prevalent HPV infection with any genotype [HR = 2.06 (95% CI = 1.44–2.94), I2 = 0%], although adjustment for confounders was often inadequate. The effect was similar for high-risk [HR = 1.99 (95% CI = 1.54–2.56), I2 = 8.4%] and low-risk [HR = 2.01 (95% CI = 1.27–3.20), I2 = 0%] HPV genotypes with weak evidence of publication bias (P = 0.06). Two studies in men were identified: both showed an association between HPV infection and HIV acquisition. Unpublished data from one of two studies in women indicated an association between genotypes targeted by HPV vaccines and HIV acquisition. PAFs for HIV attributable to infection with any HPV genotype ranged between 21 and 37%. Conclusion:If further studies validate the association between HPV infection and HIV acquisition, HPV vaccines may reduce HIV incidence in high HPV prevalence populations, in addition to preventing cervical cancer. HIV surveillance studies during implementation of HPV vaccine programmes are warranted.

Evolving immunosuppressive microenvironment during human cervical carcinogenesis

Chronic infection with human papillomavirus (HPV) can result in cervical cancer. To understand how HPV escapes immune eradication, we examined biophenotypes of immune cells in human normal cervix, cervical intraepithelial neoplasia (CIN), and cancer. Expression and cellular localization of Forkhead box protein-3 (FOXP3), indolamine 2,3-dioxygenase (IDO), interleukin (IL)-10, and interferon (IFN)-γ were examined by immunofluorescence and immunohistochemistry. Mean cell densities of stromal FOXP3+ cells, IDO+ cells, IL-10+ cells, CD1a+ cells, and macrophages significantly increased from normal cervix to cancer, whereas densities of IFN-γ+ and MMP-9+ cells increased from normal cervix to CIN but decreased in cancer. Flow cytometry confirmed significant elevation of cervical T cells expressing IFN-γ and transforming growth factor-β in CIN compared with normal cervix. Upon activation, a significantly increased proportion of cervical T cells expressed IFN-γ in CIN than normal. A unique subset of morphologically immature stromal dendritic cells expressing IL-10 and IDO was more numerous in cancer than in normal cervix and CIN. The potentially suppressive immune milieu in the cervix may be permissive of HPV-associated cervical carcinogenesis.

Functional Attributes of Mucosal Immunity in Cervical Intraepithelial Neoplasia and Effects of HIV Infection

The role of mucosal immunity in human papillomavirus (HPV)-related cervical diseases is poorly understood. To characterize the local immune microenvironment in cervical intraepithelial neoplasia (CIN) 2/3 and determine the effects of HIV infection, we compared samples from three groups: normal cervix, CIN 2/3 from immunocompetent women (HIV− CIN 2/3), and CIN 2/3 from HIV seropositive women (HIV+ CIN 2/3). CIN 2/3 lesions contained increased numbers of immune cells from both the acquired and innate arms of the immune response in stroma [CD4+ and CD8+ T cells, macrophages, mast cells, B cells, neutrophils, and natural killer (NK) cells] and dysplastic epithelium (CD4+ T cells, macrophages, and NK cells). Immune cells in CIN 2/3 expressed activation markers, as measured by interleukin-2 receptor (IL-2R) and transcription factor T bet. Interferon-γ production was significantly up-regulated in CIN lesions and was expressed by CD4+ and CD8+ T cells and NK cells, indicating the activation of immune cells. Abundant presence of transforming growth factor-β+ CD25+ cells in the infiltrates associated with CIN lesions, and of immature CD1a+ dendritic cells expressing IL-10 and transforming growth factor-β, indicate that CIN is associated with an influx of immune cells that produce a mixture of proinflammatory and regulatory cytokines. In HIV+ CIN, immune cell densities (CD4+ T cells, macrophages, neutrophils, and NK cells) and expression of interferon-γ were significantly decreased compared with HIV− CIN. Regulatory cytokines were also down-regulated in this group. Therefore, both pro- and anti-inflammatory responses present in CIN 2/3 lesions are suppressed in HIV-seropositive women.

The accuracy of colposcopic grading for detection of high-grade cervical intraepithelial neoplasia

Objective. To relate aspects of online colposcopic image assessment to the diagnosis of grades 2 and 3 cervical intraepithelial neoplasia (CIN 2+). Methods: To simulate colposcopic assessment, we obtained digitized cervical images at enrollment after acetic acid application from 919 women referred for equivocal or minor cytologic abnormalities into the ASCUS-LSIL Triage Study. For each, 2 randomly assigned evaluators from a pool of 20 colposcopists assessed images using a standardized tool online. We calculated the accuracy of these assessments for predicting histologic CIN 2+ over the 2 years of study. For validation, a subset of online results was compared with same-day enrollment colposcopic assessments. Results. Identifying any acetowhite lesion in images yielded high sensitivity: 93% of women with CIN 2+ had at least 1 acetowhite lesion. However, 74% of women without CIN 2+ also had acetowhitening, regardless of human papillomavirus status. The sensitivity for CIN 2+ of an online colpophotographic assessment of high-grade disease was 39%. The sensitivity for CIN 2+ of a high-grade diagnosis by Reid Index scoring was 30%, and individual Reid Index component scores had similar levels of sensitivity and specificity. The performance of online assessment was not meaningfully different from that of same-day enrollment colposcopy, suggesting that these approaches have similar utility. Conclusions. Finding acetowhite lesions identifies women with CIN 2+, but using subtler colposcopic characteristics to grade lesions is insensitive. All acetowhite lesions should be assessed with biopsy to maximize sensitivity of colposcopic diagnosis with good specificity.

Amplification of MDS1/EVI1 and EVI1, Located in the 3q26.2 Amplicon, Is Associated with Favorable Patient Prognosis in Ovarian Cancer

Increased copy number involving chromosome 3q26 is a frequent and early event in cancers of the ovary, lung, head and neck, cervix, and BRCA1 positive and basal breast cancers. The p110alpha catalytic subunit of phosphoinositide-3-kinase (PI3KCA) and protein kinase Ciota (PKCiota) have previously been shown as functionally deregulated by 3q copy number increase. High-resolution array comparative genomic hybridization of 235 high-grade serous epithelial ovarian cancers using contiguous bacterial artificial chromosomes across 3q26 delineated an approximately 2 Mb-wide region at 3q26.2 encompassing PDCD10 to MYNN (chr3:168722613-170908630). Ecotropic viral integration site-1 (EVI1) and myelodysplastic syndrome 1 (MDS1) are located at the center of this region, and their DNA copy number increases are associated with at least 5-fold increased RNA transcript levels in 83% and 98% of advanced ovarian cancers, respectively. Moreover, MDS1/EVI1 and EVI1 protein levels are increased in ovarian cancers and cancer cell lines. EVI1 and MDS1/EVI1 gene products increased cell proliferation, migration, and decreased transforming growth factor-beta-mediated plasminogen activator inhibitor-1 promoter activity in ovarian epithelial cells. Intriguingly, the increases in EVI1 DNA copy number and MDS1/EVI1 transcripts are associated with improved patient outcomes, whereas EVI1 transcript levels are associated with a poor patient survival. Thus, the favorable patient prognosis associated with increased DNA copy number seems to be as a result of high-level expression of the fusion transcript MDS1/EVI1. Collectively, these studies suggest that MDS1/EVI1 and EVI1, previously implicated in acute myelogenous leukemia, contribute to the pathophysiology of epithelial ovarian cancer.

Type-Specific Cervico-Vaginal Human Papillomavirus Infection Increases Risk of HIV Acquisition Independent of Other Sexually Transmitted Infections

Background Sexually transmitted infections (STIs) such as herpes simplex virus (HSV)-2 are associated with an increased risk of HIV infection. Human papillomavirus (HPV) is a common STI, but little is know about its role in HIV transmission. The objective of this study was to determine whether cervico-vaginal HPV infection increases the risk of HIV acquisition in women independent of other common STIs. Methods and Findings This prospective cohort study followed 2040 HIV-negative Zimbabwean women (average age 27 years, range 18–49 years) for a median of 21 months. Participants were tested quarterly for 29 HPV types (with L1 PCR primers) and HIV (antibody testing on blood samples with DNA or RNA PCR confirmation). HIV incidence was 2.7 per 100 woman-years. Baseline HPV prevalence was 24.5%, and the most prevalent HPV types were 58 (5.0%), 16 (4.7%), 70 (2.4%), and 18 (2.3%). In separate regression models adjusting for baseline variables (including age, high risk partner, positive test for STIs, positive HSV-2 serology and condom use), HIV acquisition was associated with having baseline prevalent infection with HPV 58 (aHR 2.13; 95% CI 1.09–4.15) or HPV 70 (aHR 2.68; 95% CI 1.08–6.66). In separate regression models adjusting for both baseline variables and time-dependent variables (including HSV-2 status, incident STIs, new sexual partner and condom use), HIV acquisition was associated with concurrent infection with any non-oncogenic HPV type (aHR 1.70; 95% CI 1.02–2.85), any oncogenic HPV type (aHR 1.96; 95% CI 1.16–3.30), HPV 31 (aHR 4.25; 95% CI 1.81–9.97) or HPV 70 (aHR 3.30; 95% CI 1.50–7.20). Detection of any oncogenic HPV type within the previous 6 months was an independent predictor of HIV acquisition, regardless of whether HPV status at the HIV acquisition visit was included (aHR 1.95; 95% CI 1.19–3.21) or excluded (aHR 1.96; 95% CI 1.02–2.85) from the analysis. Conclusions/Significance Cervico-vaginal HPV infection was associated with an increased risk of HIV acquisition in women, and specific HPV types were implicated in this association. The observational nature of our study precludes establishment of causation between HPV infection and HIV acquisition. However, given the high prevalence of HPV infection in women, further investigation of the role of HPV in HIV transmission is warranted.