Emerging roles of HSF1 in cancer: Cellular and molecular episodes

Heat shock factor 1 (HSF1) systematically guards proteome stability and proteostasis by regulating the expression of heat shock protein (HSP), thus rendering cancer cells addicted to HSF1. The non-canonical transcriptional programme driven by HSF1, which is distinct from the heat shock response (HSR), plays an indispensable role in the initiation, promotion and progression of cancer. Therefore, HSF1 is widely exploited as a potential therapeutic target in a broad spectrum of cancers. Various molecules and signals in the cell jointly regulate the activation and attenuation of HSF1. The high-level expression of HSF1 in tumours and its relationship with patient prognosis imply that HSF1 can be used as a biomarker for patient prognosis and a target for cancer treatment. In this review, we discuss the newly identified mechanisms of HSF1 activation and regulation, the diverse functions of HSF1 in tumourigenesis, and the feasibility of using HSF1 as a prognostic marker. Disrupting cancer cell proteostasis by targeting HSF1 represents a novel anti-cancer therapeutic strategy.