Zhang, Qing

Abstract Background: Most ovarian cancer (OC) patients present with advanced disease and ultimately develop chemo-resistant relapses. Stroma plays a significant role in OC behavior including invasiveness, fibrosis and chemoresistance. TGF-β is important for crosstalk between stroma and cancer cells, and stromal activation in cancer has similarities to matrix remodeling in fibrosis. We have shown that TGF-β and fibrosis-inhibitors can suppress OC cell proliferation, migration and invasion. Such inhibitors are available for clinical use, and we have begun to test their efficacy in OC in vivo. Methods: Animal experiments were approved by Mayo Clinic IACUC. Intraperitoneal xenograft models were derived from OVCAR8 (5×106) cells (OV8-CDX) or 0.1 gm OC patient tumor tissue (PDX) in NSG mice. OV8-CDX and PDX PH003 (an aggressive, chemoresistant and ascites-prone model) (n=5-10 mice/arm) were treated with 2 agents and compared to untreated controls (C): 1) C vs. the fibrosis inhibitor Pirfenidone (P, 200 mg/kg, BID, provided by Genentech); 2) C vs. TGF-β receptor I inhibitor Galunisertib (G, 75 mg/kg, BID, provided by Eli Lily). Mice were pretreated for 2 days before xenografting and treated for 4 weeks with ultrasound (US) to measure tumor growth. At day (d) 28, we i) collected tumor (OV8-CDX); or ii) observed until progression (PH003, PH053). OV8-CDX tumors were used for target gene analysis. Results: P treatment delayed tumor growth in OV8-CDX relative to control (C): tumors established in 0/5 (P) vs. 1/5 (C), and 1/5 (P) vs. 4/5 (C) of mice at d14 and d28, respectively. The reduced tumor weight (g) at d28 was also confirmed (0.20±0.10 vs. 0.54±0.23, p=0.02). Similarly, P treatment in PH003 inhibited the tumor growth (tumor area (cm2) at d28: 0.74±0.43 vs. 1.04±0.51, p=0.28), ascites development (volume (ml): 1.14±0.54 vs. 3.37±0.62, p=0.05) and prolonged survival time (p=0.04). G treatment was also associated with delayed tumor establishment in OV8-CDX relative to C: tumors presented in 0/5 (G) vs. 1/5 (C), and 1/5 (G) vs. 4/5 (C) of mice at d14 and d28, respectively. Associated d28 tumor weight was significantly reduced (0.20±0.10 vs. 0.54±0.23, p=0.02) as well. For PH003, G treatment was associated with delayed tumor growth (tumor area at d28: 0.57±0.27 vs. 1.04±0.51, p=0.05), a marked reduction in ascites (volume: 1.25±0.56 vs. 3.37±0.62, p=0.05) and a prolonged survival time (p=0.04) We identified down-regulation of TGF-β signaling-related genes (e.g. TGFB1, TGFBR2) and fibrosis-related biomarkers (e.g. FAP, COL11A1) following drug treatment confirming inhibition of relevant pathways. Conclusion: We report that 2 currently available inhibitors targeting either fibrosis or TGF-β appear to have efficacy in vivo and delay tumor growth in OC PDX models. These results suggest promise for a strategy of targeting the stromal component of OC. Citation Format: Qing Zhang, Xiaonan Hou, Bradley J. Evans, John J. Weroha, William A. Cliby. Inhibitors of fibrosis and TGF-beta delay tumor xenograft growth and reduce ascites in ovarian cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 961. doi:10.1158/1538-7445.AM2017-961

Abstract Recent molecular and pathologic evidence indicate that high-grade serous carcinomas of the ovary, which are the most common type of epithelial carcinomas, may arise from the distal part of fallopian tubes or tubal carcinoma implants. Oviductal glycoprotein 1 (Ovgp1), a glycosylated protein found in the epithelial cells in the oviduct, is the only specific tubal marker so far. Ovgp1 promoter-driven SV40 large T-antigen transgenic mice develop tumors in the female reproductive organs. To characterize these tumors, we performed immunohistochemical analysis in paraffin-embedded sections. Mice were sacrificed at 8 or 13 weeks old. Macroscopically we observed large tumors in the uterus and cervix and markedly enlarged region in the oviduct. Due to the large tumor in the uterus and cervix, we could not keep the mice longer than 13 weeks. Histologically, there were no major differences in these affected regions between 8 weeks old and 13 weeks old mice. We observed, (i) relatively small ovaries and ovarian follicular hyperplasia, (ii) intact ovarian surface epithelium showing no atypical histology, (iii) atypical epithelial hyperplasia within the oviduct (with endometrioid architectural and cytologic features), (iv) leiomyosarcomatous proliferation in the myometrium, and (v) squamous carcinoma in situ in the cervix or early invasive cervical cancer with extensive papillary architecture. We did not detect metastasis from the tumor to other organs. The atypical abnormalities of the oviduct were more significant in the proximal site to the uterus than the distal site. The proximal oviduct demonstrated weak and spotty p53 expression, beneath the epithelium, similar to p53 signature in the human oviduct. We hypothesized that stem cell components may contribute to the tumor development and that putative cancer stem cells could be identified by stem cell markers. In the oviduct epithelium, Bmi1 expression was not detectable. Cytoplasmic expression of Sox2 was observed in all epithelial cells of the oviduct. There was little correlation between Sox2/Bmi1 staining and p53 staining in the oviduct. Interestingly, Sox2 and Bmi1 staining in the wild-type control mice showed immunoreactive cells interspersed between glandular structures, a pattern similar to previously described label-retaining cells in the endometrium. The expression pattern in Ovgp1-SV40 mice, Bmi1 and Sox2 expression were more obvious in the endometrial stromal area but not in the leiomyosarcoma region, which implies that stem cell components in the endometrial region may support the leiomyosarcoma progression in this mouse model. In conclusion, Ovgp1-SV40 transgenic mouse is a useful model for studies involving fallopian and lower genital tract carcinogenesis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3272. doi:1538-7445.AM2012-3272