Function of Hsf1 in SV40 T‑antigen‑transformed HEK293T cells.

Heat shock factor 1 (HSF1), a main regulator of the heat shock response in eukaryotes, increases cell survival in numerous pathophysiological conditions. The aim of the present study was to o bserve the function of defective HSF1 expression in HEK293T cells. shRNA of human HSF1 was constructed into the retroviral vector pLTHR generating pLTHR‑shRNA‑HSF1. The shRNA was transiently transfected into HEK293T cells to silence the expression of the HSF1 gene. Cell colony formation, MTT and cell cycle assays were used to analyze the SV40 T‑antigen (Ag)‑transformed cell proliferation rate. Immunoblotting was used to study the protein expression of HSF1, SV40 T‑Ag, p53, p21, heat shock protein 90 (Hsp90), Hsp70 and Hsp25. The results revealed that a deficiency in HSF1 expression inhibited cellular growth. Defective HSF1 upregulated the protein expression of p53, retinoblastoma protein (Rb) and SV40 T‑Ag, and reduced the association between SV40 T‑Ag and p53/Rb, which resulted in growth inhibition of SV40 T‑Ag‑transformed cells. In conclusion, HSF1 is involved in the regulation of SV40 T‑Ag‑induced cell growth and modulates the expression of p53 and Rb proteins.