Citations

Abstract It was well accepted for many years that ovarian surface epithelium is the origin of epithelial ovarian carcinomas. However, recent molecular and pathologic evidence indicate that high-grade serous carcinomas of the ovary, which are the most common type of epithelial carcinomas, may also arise from the distal part of fallopian tubes or tubal carcinoma implants. Gene expression profiles of tubal epithelium from BRCA mutation carriers resemble those of high-grade serous carcinomas of the ovary, and ovarian carcinomas and tubal intraepithelial carcinomas have identical p53 mutations. Oviductal glycoprotein 1 (Ogp1) is a glycosylated protein found in the epithelial cells in the oviduct. So far, Ogp1 is the only specific tubal marker for the oviduct. Ogp1 promoter-driven SV40 large T-antigen transgenic mice develop tumors in the female reproductive organs. To characterize these tumors, we did immunohistochemical analysis in frozen and paraffin-embedded sections. Mice were sacrificed at 8 weeks old. Macroscopically the cervico-vaginal region and the fallopian tubes were markedly enlarged. Histologically, three distinct abnormal proliferations were observed; (i) epithelial hyperplasia with cytologic atypia in the oviduct (with endometrioid architectural and cytologic features), (ii) leiomyosarcomatous proliferation in the myometrium, and (iii) squamous carcinoma in situ in the cervix with extensive papillary architecture. SV40 was expressed in these tumor sites. The oviduct demonstrated weak and spotty p53 expression. The expression of Ogp1 and Pax8 (a marker of the salpingeal secretory cells) in the oviduct epithelium showed patchy pattern. Ogp1 expression was not associated with cellular atypia, while Pax8 was expressed in normal cells. Expression of DNA replication licensing factor, Mini-chromosome maintenance protein 7(MCM7), was also mixed. MCM7 expression was higher in neoplastic cells, but atypical cells had less MCM7 expression. A serous marker, WT1, and a Müllerian-specific epithelial marker, Pax2, showed lower expressions in Ogp1-SV40 transgenic mouse compared to wild type control mouse. WT1 and Pax2 expression were uniform. In ovarian surface epithelium, there was no malignant transformation and no different expression of these markers in control and Ogp1-SV40 mice. In conclusion, this study demonstrated that Ogp1-SV40 transgenic mouse develops abnormal oviductal, myometrial, and cervical proliferations with no involvement of ovaries. Weak and spotty p53 expression in the oviduct indicates that p53 pre-dysfunction status in non-malignant precursor lesions. These results indicate that Ogp1-SV40 transgenic mouse is a useful model for studies involving fallopian and low genital tract carcinogenesis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3276.

Abstract Mini-Chromosome Maintenance protein 7 (MCM7) is involved in replicative licensing and synthesis of DNA. It is previously identified as over-expressed gene in high-grade serous carcinomas compared to serous borderline tumors of the ovary in cDNA microarray studies. In this study, we sought to validate MCM7 expression in ovarian tumors by applying immunohistochemical analysis on tissue microarrays consisting of 445 ovarian tumors. MCM7 expression was quantified as MCM7 labeling index by determining the tumor nuclei positive for MCM7 staining as a percentage of total tumor nuclei. The labeling index scores were independently generated by two methods: PATH score provided by a manual review of each samples by a pathologist and ACIS score provided by Automated Cell Imaging System. Analyses of both scores indicated high degree of concordance in score distribution between PATH and ACIS. MCM7 expression is significantly higher in high-grade serous carcinomas compared to serous borderline tumors, confirming our previous cDNA microarray studies. In both PATH and ACIS analysis, MCM7 expression is also significantly higher in high-grade serous carcinomas compared to other histology subtypes of ovarian cancer. Finally, to identify the clinical significance of MCM7 expression, we determined the association between MCM7 expression and disease-free survival. MCM7 labeling index was dichotomized into two groups (high and low) using median labeling index as cut-off. For both PATH or ACIS-derived scores, univariate analyses indicate significant association of high MCM7 labeling index with better disease-free survival in high-grade serous carcinomas. These results suggest the clinical significance of MCM7 expression in high-grade serous carcinomas of the ovary and the need for further evaluation of MCM7 as a potential theranostic biomarker. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4637.

AbstractPurpose: The purpose of this study was to determine if loss of serine protease HtrA1 in endometrial cancer will promote the invasive potential of EC cell lines.Experimental design: Western blot analysis and immunohistochemistry methods were used to determine HtrA1 expression in EC cell lines and primary tumors, respectively. Migration, invasion assays and in vivo xenograft experiment were performed to compare the extent of metastasis between HtrA1 expressing and HtrA1 knocked down clones.Results: Western blot analysis of HtrA1 in 13 EC cell lines revealed complete loss of HtrA1 expression in all seven papillary serous EC cell lines. Downregulation of HtrA1 in Hec1A and Hec1B cell lines resulted in a three- to fourfold increase in the invasive potential. Exogenous expression of HtrA1 in Ark1 and Ark2 cells resulted in three- to fourfold decrease in both invasive and migration potential of these cells. There was an increased rate of metastasis to the lungs associated with HtrA1 downregulation in Hec1B cells compared to control cells with endogenous HtrA1 expression. Enhanced expression of HtrA1 in Ark2 cells resulted in significantly less tumor nodules metastasizing to the lungs compared to parental or protease deficient (SA mutant) Ark2 cells. Immunohistochemical analysis showed 57% (105/184) of primary EC tumors had low HtrA1 expression. The association of low HtrA1 expression with high-grade endometrioid tumors was statistically significant (P = 0.016).Conclusions: Collectively, these data indicate loss of HtrA1 may contribute to the aggressiveness and metastatic ability of endometrial tumors. Clin Cancer Res; 17(3); 427–36. ©2010 AACR.

Abstract We previously identified serine protease HtrA1 as a downregulated gene in epithelial ovarian cancer (EOC), but the functional consequence of loss of HtrA1 in EOC remains largely unclear. Here, we report that loss of HtrA1 attenuates anoikis—a critical physiologic barrier for tumor metastasis. In response to loss of anchorage, HtrA1 expression was upregulated in SKOV3 cells, resulting in autocatalytic activation of HtrA1. Stable knockdown of HtrA1 in SKOV3 and TOV21G cells resulted in resistance to anoikis due to enhanced activation of epidermal growth factor receptor (EGFR)/AKT pathway. In suspended SKOV3 cells, enhanced expression of HtrA1 inhibited EGFR/AKT pathway, leading to increased cell death, whereas protease-inactive mutant HtrA1 failed to result in either the inhibition of EGFR/AKT pathway or increased cell death, suggesting the requirement of HtrA1 protease activity in regulating anoikis. Immunoprecipitation and immunofluorescence assays revealed that HtrA1 interacted with EGFR not only on the cell membrane but also in the nucleus. Most importantly, downregulation of HtrA1 significantly enhanced the peritoneal dissemination of SKOV3ip1 cells in nonobese diabetic/severe combined immunodeficient mice, with increased phospho-EGFR level in corresponding tumor nodules compared with that in xenografts originated from the control cells. Taken together, these data reveal for the first time a novel function of HtrA1 in promoting anoikis by attenuating activation of EGFR/AKT pathway that may contribute to its metastasis suppression capacity, thus providing a possible explanation for the aggressive nature of human ovarian tumors with downregulated HtrA1. Cancer Res; 70(8); 3109–18. ©2010 AACR.