Abstract 2033: Transcription factors that regulate MUC16 expression in ovarian cancer

Abstract

Abstract CA125 antigen is found to be elevated in 85% of patients diagnosed with advanced epithelial ovarian cancer. CA125 has a minimal role as a screening modality. The gene which encodes for the CA125 glycoprotein, MUC16, has been previously identified and sequenced. MUC16 has a molecular size of 22,000 bps and consists of cytoplasmic domain, transmembrane region and 9 external domain tandem repeats. The large molecular weight of this gene has made it difficult to study and track. N terminal signal peptide and transcription factor or factors that triggers MUC16 in ovarian cancer is not well demonstrated. The proximal 114 amino acids of MUC16 can transform NIH/3T3 cells and increase soft agar formation and matrigel invasion. We have designed several constructs from the region about 1000 nucleotides upstream and 300 nucleotides downstream of the MUC16 start Methionine with secretory pMetridia Luciferase Reporter vector (Clonetech, CA). Four constructs of varying lengths had the MUC16 UTR TSS site whereas two did not. Putative binding sites for transcription factors like ER, STAT1, STAT3, CRE-BP1 (ATF2) and NFKB are also present. These constructs were then transfected individually into CA125 negative ovarian cell line, SK-Ov-3, and also into CA125 positive ovarian cell lines, SK-Ov-8 and CAOV3. All cell lines were stably selected with G418 and were used within 10 passages. Western blots confirm the presence of ERalpha, STAT1 and STAT3. Stably transfected cell lines were cultured in low serum conditions with or without 17β-Estradiol or IL-1β, were used to see the effect of transcription. Clinical CA125 levels were also documented for each construct. Secretory pMetridia Luciferase signals were detected in the supernant of the culture cells. There is no difference between untreated or 17β-Estradiol or IL-1β treated cells. However, gel retardation studies with OVCAR3 and SKOV8 wild type cell lines suggested CREB/ATF (CREBZF) transcription factor involvement and confirmatory reporter gene studies are planned. Currently, we are assessing the putative transcription factor binding sites within the 1300 nucleotides region from which we derived the constructs. We conclude that these studies will lead us to better understand the biology of MUC16 gene expression and give us an insight about the role of transcription factors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2033. doi:10.1158/1538-7445.AM2011-2033