HtrA3 Is Downregulated in Cancer Cell Lines and Significantly Reduced in Primary Serous and Granulosa

licenses/by-nc-nd/3.0/). Reproduction is permitted for personal, noncommercial use, provided that the article is in whole, unmodified, and properly cited. Received: 2012.12.13; Accepted: 2013.01.10; Published: 2013.02.01 Objective. The high temperature requirement factor A3 (HtrA3) is a serine protease homolo-gous to bacterial HtrA. Four human HtrAs have been identified. HtrA1 and HtrA3 share a high degree of domain organization and are downregulated in a number of cancers, suggesting a widespread loss of these proteases in cancer. This study examined how extensively the HtrA (HtrA1-3) proteins are downregulated in commonly used cancer cell lines and primary ovarian tumors. Methods. RT-PCR was applied to various cancer cell lines (n=17) derived from the ovary, en-dometrium, testes, breast, prostate, and colon, and different subtypes of primary ovarian tumors [granulosa cell tumors (n=19), mucinous cystadenocarcinomas (n=6), serous cystadenocarcino-mas (n=8)] and normal ovary (n = 9). HtrA3 protein was localized by immunohistochemistry. Results. HtrA3 was extensively downregulated in the cancer cell lines examined including the granulosa cell tumor-derived cell lines. In primary ovarian tumors, the HtrA3 was significantl