Gustavo C. Rodriguez

Effect of progestin on the ovarian epithelium of macaques : Cancer prevention through apoptosis?

Objective: The apoptosis pathway is a vital mechanism in vivo that functions to eradicate genetically damaged cells prone to malignancy. The purpose of this study was to determine whether oral contraceptives, which confer significant protection against subsequent epithelial ovarian cancer, induce apoptosis in the ovarian epithelium. Methods: Female cynomologus macaques (N = 75) were randomized to receive a diet for 35 months containing either no hormones, the oral contraceptive Triphasil (Wyeth-Ayerst Laboratories, Philadelphia, PA), the estrogenic component of Triphasil (ethinyl estradiol) alone, or the progestin component of Triphasil (levonorgestrel) alone, each administered in a cyclic fashion. At study termination, the animals underwent ovariectomy and the ovarian epithelium was examined morphologically and immunihistochemically for apoptosis. The percentage of ovarian epithelial cells undergoing apoptosis was measured in each animal and compared between the treatment groups. Results: The median percentage of ovarian epithelial cells undergoing apoptosis by treatment was control (3.8%), ethinyl estradiol (1.8%), Triphasil (14.5%), and levonorgesrel (24.9%). Compared with control and ethinyl estradiol-treated monkeys, a statistically significant increase in the proportion of apoptotic cells was noted in the ovarian epithelium of monkeys treated with the oral contraceptive Triphasil (P ≤ .01) or levonorgestrel (P < .001), with a maximal effect (six-fold) seen in the group treated with levonorgestrel alone. Conclusion: Oral contraceptive progestin induces apoptosis in the ovarian epithelium. Given the importance of the apoptosis pathway for cancer prevention, an effective chemopreventive strategy may be possible using progestins or other agents that selectively induced apoptosis in the ovarian epithelium to prevent the development of ovarian cancer.

Ovarian cancer: etiology, risk factors, and epidemiology.

Little is known regarding the early aspects of ovarian carcinogenesis. As a consequence, the identification of women at risk for the disease is based primarily on clinical grounds, with family history being the most important risk factor. In this review, we will discuss the various hypotheses regarding ovarian etiology and pathogenesis. In addition, we will discuss the epidemiology of ovarian cancer, including hereditary, reproductive, hormonal, inflammatory, dietary, surgical, and geographic factors that influence ovarian cancer risk.

A Prospective Study of Risk-Reducing Salpingo-oophorectomy and Longitudinal CA-125 Screening among Women at Increased Genetic Risk of Ovarian Cancer: Design and Baseline Characteristics: A Gynecologic Oncology Group Study

Background: Women who are genetically predisposed to ovarian cancer are at very high risk of developing this disease. Although risk-reducing salpingo-oophorectomy (RRSO) and various screening regimens are currently recommended to reduce ovarian cancer risk, the optimal management strategy has not been established nor have multiple additional issues been adequately addressed. We developed a collaboration among the Clinical Genetics Branch (National Cancer Institutes Intramural Research Program), the Gynecologic Oncology Group (GOG), and the Cancer Genetics Network to address these issues. Methods: This is a prospective, international, two-cohort, nonrandomized study of women at genetic risk of ovarian cancer, who chose either to undergo RRSO or screening, at study enrollment. Primary study objectives include quantifying and comparing ovarian and breast cancer incidence in the two study groups, assessing feasibility and selected performance characteristics of a novel ovarian cancer screening strategy (the Risk of Ovarian Cancer Algorithm), evaluating various aspects of quality of life and nononcologic morbidity related to various interventions in at-risk women, and creating a biospecimen repository for subsequent translational research. Results: Study accrual is complete as of November 2006; 2,605 participants enrolled: 1,030 (40%) into the surgical cohort and 1,575 (60%) into the screening cohort. Five years of prospective follow-up ends in November 2011. Verification of BRCA mutation carrier status is under way, either through patient-provided reports from clinical genetic testing done before enrollment or through research-based genetic testing being conducted as part of the protocol. Patient eligibility is currently under evaluation and baseline, surgical, pathology, and outcome data are still being collected. The study design and selected baseline characteristics of cohort members are summarized. Conclusion: This National Cancer Institute intramural/extramural collaboration will provide invaluable prospectively collected observational data on women at high familial ovarian cancer risk, including substantial numbers of women carrying BRCA1/2 mutations. These data will aid in elucidating the effect of RRSO on breast/ovarian cancer risk and the effects of two management strategies, on quality of life and other issues that may influence patient care, as well as providing preliminary estimates of test specificity and positive predictive value of a novel ovarian cancer screening strategy. (Cancer Epidemiol Biomarkers Prev 2008;17(3):594–604)

A comparison of the Pipelle device and the Vabra aspirator as measured by endometrial denudation in hysterectomy specimens: The Pipelle device samples significantly less of the endometrial surface than the Vabra aspirator

OBJECTIVEnThe distribution and relative area of endometrial sampling of two endometrial biopsy techniques, Pipelle and Vabra aspiration biopsy, were compared.nnnSTUDY DESIGNnTwenty-five patients scheduled for hysterectomy were randomly assigned to undergo preoperative endometrial biopsy by Pipelle device (12 patients) or Vabra aspiration (13 patients). The endometrial cavities of the surgical specimens were photographed, and percent denudation was determined by a point-counting method.nnnRESULTSnThe percentage of endometrial surface area sampled by the Pipelle device was 4.2% +/- 0.92% (mean +/- SEM), and by Vabra aspirator 41.6% +/- 5.7% (p < 0.0001). The mean number of endometrial surfaces (one anterior and one posterior) sampled by the Pipelle device was 1.08 +/- 0.15, and by the Vabra aspirator 2 +/- 0 (p = 0.001). The mean number of endometrial quadrants (four anterior plus four posterior) sampled by the Pipelle device was 2.4 +/- 0.41, and by the Vabra aspirator 7.4 +/- 0.42 (p < 0.0001).nnnCONCLUSIONnWe conclude that the Vabra aspirator is statistically superior to the Pipelle device for sampling the endometrial cavity when the total surface area sampled and the distribution of surfaces sampled are considered.

Large prospective study of ovarian cancer screening in high-risk women: CA125 cut-point defined by menopausal status

Previous screening trials for early detection of ovarian cancer in postmenopausal women have used the standard CA125 cut-point of 35 U/mL, the 98th percentile in this population yielding a 2% false positive rate, whereas the same cut-point in trials of premenopausal women results in substantially higher false positive rates. We investigated demographic and clinical factors predicting CA125 distributions, including 98th percentiles, in a large population of high-risk women participating in two ovarian cancer screening studies with common eligibility criteria and screening protocols. Baseline CA125 values and clinical and demographic data from 3,692 women participating in screening studies conducted by the National Cancer Institute–sponsored Cancer Genetics Network and Gynecologic Oncology Group were combined for this preplanned analysis. Because of the large effect of menopausal status on CA125 levels, statistical analyses were conducted separately in pre- and postmenopausal subjects to determine the impact of other baseline factors on predicted CA125 cut-points on the basis of 98th percentile. The primary clinical factor affecting CA125 cut-points was menopausal status, with premenopausal women having a significantly higher cut-point of 50 U/mL, while in postmenopausal subjects the standard cut-point of 35 U/mL was recapitulated. In premenopausal women, current oral contraceptive (OC) users had a cut-point of 40 U/mL. To achieve a 2% false positive rate in ovarian cancer screening trials and in high-risk women choosing to be screened, the cut-point for initial CA125 testing should be personalized primarily for menopausal status (50 for premenopausal women, 40 for premenopausal on OC, and 35 for postmenopausal women). Cancer Prev Res; 4(9); 1401–8. ©2011 AACR.

Progesterone and 1,25-Dihydroxyvitamin D3 Inhibit Endometrial Cancer Cell Growth by Upregulating Semaphorin 3B and Semaphorin 3F

Class 3 semaphorins (SEMA), SEMA3B and SEMA3F, are secreted proteins that regulate angiogenesis, tumor growth, and metastasis by binding to their transmembrane receptor complex consisting of plexins and neuropilins (NP). Expression of SEMAs and their receptors was assessed in tissue microarrays by immunohistochemistry. SEMA3B, SEMA3F, and plexin A3 were expressed strongly in normal endometrial tissues, whereas grade-dependent decreases were found in endometrial carcinomas. No change was observed in the expression of plexin A1, NP1, and NP2 in normal versus endometrial cancer tissues. Endometrial cancer cells showed decreased expression of SEMA3B, SEMA3F, and plexin A3 compared with their normal counterparts. Treatment of cancer cells with progesterone (P4) and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] for a period of 72 hours induced a significant upregulation of SEMA3B and SEMA3F as well as inhibited growth of cancer cells by increasing caspase-3 activity. Cotreatment of cell lines with P4 or 1,25(OH)2D3 and their respective antagonists confirmed the specificity of their actions. Transfection of siRNA-targeting SEMA3B and SEMA3F in endometrial cancer cells attenuated P4 or 1,25(OH)2D3-induced growth inhibition. Restoration of SEMA3B or SEMA3F expression in cancer cells caused growth inhibition, reduced soft agar colony formation, and cell invasiveness by inhibiting expression of matrix metalloproteinase-2 (MMP-2), MMP-9, integrin αvβ3, and proangiogenic genes and by upregulating antiangiogenic genes. Thus, we have identified two new P4 and 1,25(OH)2D3-regulated antitumor genes for endometrial cancer. These results suggest that the loss of SEMAs contribute to the malignant phenotype of endometrial cancer cells and that reexpression of SEMAs by ectopic expression or with anticancer agents P4 or 1,25(OH)2D3 can be a promising therapeutic treatment against endometrial cancer. Mol Cancer Res; 9(11); 1479–92. ©2011 AACR.

The role of neoadjuvant chemotherapy in treating advanced epithelial ovarian cancer.

The current management of advanced ovarian cancer consists of aggressive primary cytoreductive surgery (PCS) followed by combination platinum based chemotherapy. Recent studies have suggested that platinum‐based chemotherapy may be of benefit in patients with advanced ovarian cancer prior to cytoreductive surgery (neoadjuvant chemotherapy, NACT). The concept of NACT has not been completely validated in the treatment of ovarian cancer. This review will discuss the role of NACT in patients with advanced epithelial ovarian cancer. J. Surg. Oncol. 2010; 101:334–343.

Progesterone enhances calcitriol antitumor activity by upregulating vitamin D receptor expression and promoting apoptosis in endometrial cancer cells.

Human studies suggest that progesterone and calcitriol may prove beneficial in preventing or inhibiting oncogenesis, but the underlying mechanism is not fully understood. The current study investigates the effects of progesterone, calcitriol, and their combination on immortalized human endometrial epithelial cells and endometrial cancer cells and identifies their targets of action. Combination treatment with both agents enhanced vitamin D receptor expression and inhibited cell proliferation through caspase-3 activation and induction of G0–G1 cell-cycle arrest with associated downregulation of cyclins D1 and D3 and p27 induction. We used mass spectrometry–based proteomics to measure protein abundance differences between calcitriol-, progesterone-, or combination-exposed endometrial cells. A total of 117 proteins showed differential expression among these three treatments. Four proteins were then selected for validation studies: histone H1.4 (HIST1H1E), histidine triad nucleotide-binding protein 2 (HINT2), IFN-induced, double-stranded RNA-activated protein kinase (EIF2AK2), and Bcl-2–associated X protein (BAX). Abundance levels of selected candidates were low in endometrial cancer cell lines versus the immortalized endometrial epithelial cell line. All four proteins displayed elevated expression in cancer cells upon exposure to calcitriol, progesterone, or the combination. Further BAX analysis through gain- or loss-of-function experiments revealed that upregulation of BAX decreased cell proliferation by changing the BAX:BCL-2 ratio. Knockdown of BAX attenuated progesterone- and calcitriol-induced cell growth inhibition. Our results showed that progesterone and calcitriol upregulate the expression of BAX along with other apoptosis-related proteins, which induce inhibition of endometrial cancer cell growth by apoptosis and cell-cycle arrest. Cancer Prev Res; 6(7); 731–43. ©2013 AACR.

Progestin Treatment Induces Apoptosis and Modulates Transforming Growth Factor-β in the Uterine Endometrium

Background: Epidemiologic, animal, and human data suggest that progestins are potent endometrial cancer preventive agents. In the ovarian surface epithelium, progestins have been hypothesized to confer a cancer preventive effect via apoptosis and modulation of transforming growth factor-β (TGF-β). Given that the ovarian epithelium and endometrium share a common embryologic origin and similar reproductive and hormonal risk factors for malignancy, we tested the hypothesis that progestins confer biological effects in the endometrium similar to those in the ovary. Methods: Postmenopausal female macaques (n = 78) were randomized into four groups to receive a diet for 36 months containing no hormone versus conjugated equine estrogen (CEE), medroxyprogesterone acetate (MPA), or CEE + MPA. The endometrium was then examined immunohistochemically for treatment-specific changes using antibodies to activated caspase-3 (for apoptosis), Ki-67 (proliferation), and the TGF-β1, TGF-β2, and TGF-β3 isoforms. Results: Percentages of caspase-positive endometrial glandular cells were 3- to 5-fold higher in CEE + MPA–treated animals compared with all others (P < 0.05). Caspase-expressing cells were six times more numerous in the endometrial stroma of animals treated with MPA alone relative to other groups (P < 0.0001). Induction of endometrial glandular cell apoptosis in the CEE + MPA–treated group was associated with a dramatic increase in expression of TGF-β2 and TGF-β3 in the stromal compartment of the endometrium (P < 0.0001). Conclusion: Progestin treatment activates chemopreventive biological effects in the endometrium that are similar to those in the ovarian surface epithelium. These data may facilitate identification of a chemopreventive approach that dramatically lessens the risk of both uterine and ovarian cancer. (Cancer Epidemiol Biomarkers Prev 2008;17(3):578–84)

Comparison of gene expression patterns between avian and human ovarian cancers

OBJECTIVESnA putative model of spontaneous cancer has been described in the laying hen that bears significant similarities to human ovarian cancer. Our objective was to characterize and compare the patterns of gene expression in chicken and human forms of this disease.nnnMETHODSnRNA from 20 localized and metastatic ovarian and oviductal chicken tumor samples was isolated, amplified using in vitro transcription, and hybridized against normal ovarian epithelium to a customized cDNA microarray constructed for these studies. Differentially expressed genes were identified for localized ovarian, metastatic ovarian, and oviductal (or tubal) cancer by class comparison using BRB-ArrayTools. Results were validated with semi-quantitative PCR. A gene list (prediction model) constructed with the class prediction tool was used in a human ovarian cancer microarray obtained from the GEO datasets (GSE6008) in order to compare these results across species.nnnRESULTSnClass comparison analysis between localized ovarian, metastatic ovarian and oviductal cancer yielded 41 different informative probes that coded for 27 unique genes. Localized ovarian samples clustered between metastatic ovarian and oviductal cancer samples. Using our chicken data as a training set and leaving oviductal samples out of the analysis, we created a prediction model that classified early stage and advanced stage human ovarian cancer gene expression arrays with 78% overall accuracy.nnnCONCLUSIONSnGene expression of spontaneous ovarian cancer in the chicken is comparable to gene expression patterns of human ovarian cancer.