Abstract 1304: HSF1 facilitates cell transformation by enhancing the expression of extracellular proteins

• Published in: Cancer research (Chicago, Ill.) Vol. 73; no. 8_Supplement; p. 1304
• Main Authors: Kuo, Hsiao-Hui, Yih, Ling-Huei
• Format: Journal Article
• Language: English
• Published: 15.04.2013
• ISSN: 0008-5472; 1538-7445
• DOI: 10.1158/1538-7445.AM2013-1304

Abstract The expression level or the activity of heat shock factor-1 (HSF1), a master transcriptional regulator of the heat shock response, is elevated in cancer cell lines and tumor tissues. Loss of HSF1 function has been demonstrated to prevent oncogenesis. We thus examined whether and how HSF1 induces cell transformation using anchorage-independent growth as a surrogate for transformation phenotype. CGL2 cells overexpressing HSF1 (CGL2-wtHSF1) were more proficient to form colonies in soft agar than the parental control cells (CGL2-Neo). Cells stably depleted of HSF1 (CGL2-shHSF1), on the other hand, were unable to form colonies in soft agar. The diminished ability of CGL2-shHSF1 cells to grow in soft agar was rescued by ectopic expression of wild-type HSF1 but not an S326A substitution mutant or a C-terminal (transactivation domain) deletion mutant, indicating that phosphorylation at S326 and/or the transactivation activity of HSF1 was required for its ability to enhance anchorage-independent growth. In addition, conditioned medium collected from HSF1-overexpressing cells could induce anchorage-independent growth of HSF1-depleted cells. These results indicated that HSF1 might enhance cell transformation by transactivating the expression of particular extracellular proteins. Citation Format: Hsiao-Hui Kuo, Ling-Huei Yih. HSF1 facilitates cell transformation by enhancing the expression of extracellular proteins. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1304. doi:10.1158/1538-7445.AM2013-1304