Heat shock factor 1 in cancer-associated fibroblasts is a potential prognostic factor and drives progression of oral squamous cell carcinoma.

Heat shock factor 1 (HSF1) is highly expressed in various malignancies and is a potential modulator of tumor progression. Emerging evidence suggests that HSF1 activation in stromal cells is closely related to poor patient prognosis. However, the role of HSF1 in oral squamous cell carcinoma (OSCC) remains elusive. We aimed to investigate the function of HSF1 in cancer-associated fibroblasts (CAFs) of the tumor microenvironment (TME) and in tumor development. In the present study, we found that HSF1 was highly expressed in both CAFs and tumor cells, and was significantly correlated with poor prognosis and overall survival. Moreover, HSF1 overexpression in CAFs resulted in a fibroblast-like phenotype of Cal27 cells, induced epithelial-mesenchymal transition (EMT), and promoted proliferation, migration and invasion in Cal27 cells. HSF1 knockdown attenuated features of CAFs and reduced EMT, proliferation, migration and invasion in Cal27 cells. Furthermore, HSF1 in CAFs promoted tumor growth in nude mice. Taken together, these data suggest that HSF1 expression in CAFs drive OSCC progression, and could serve as an independent prognostic marker of patients with OSCC. Thus, HSF1 is a potent mediator of OSCC malignancy.