Heat shock proteins and exosomes in cancer theranostics

Heat shock proteins (HSPs) are a superfamily of molecular chaperones that were discovered through their ability to be induced by different stresses including heat shock. Other than their function as chaperones in proteins homeostasis, HSPs have been shown to inhibit different forms of cell death and to participate in cell proliferation and differentiation processes. Because cancer cells have to rewire their metabolism, they require a high amount of these stress-inducible chaperones for their survival. Therefore, HSPs are unusually abundant in cancer cells where they have oncogene-like functions. In cancer, HSPs have been involved in the regulation of apoptosis, immune responses, angiogenesis, metastasis and treatment resistance. Recently, HSPs have been shown to be secreted through exosomes by cancer cells. These tumor-derived exosomes can be used as circulating markers: HSP-exosomes have been reported as biomarkers of cancer dissemination, response to therapy and/or patient outcome. A new range of functions, mostly in modulation of anticancer immune responses, have been described for these extracellular HSPs. In this review, we will describe those recently reported functions of HSP-exosomes that makes them both targets for anticancer therapeutics and biomarkers for the monitoring of the disease. We will also discuss their emerging interest in cancer vaccines.

Automated summary

Heat shock proteins (HSPs) are a superfamily of molecular chaperones that play important roles in protein homeostasis, cell proliferation, differentiation, and inhibiting cell death. In cancer cells, HSPs are highly abundant and have been found to be involved in processes such as apoptosis regulation, immune responses, angiogenesis, metastasis, and treatment resistance. Additionally, cancer cells can secrete HSPs through exosomes, which can serve as biomarkers for cancer dissemination, therapy response, and patient outcome. These extracellular HSPs also have emerging functions in modulating anticancer immune responses. This review focuses on describing the recently reported functions of HSP-exosomes as therapeutic targets and disease biomarkers in cancer, as well as their potential in cancer vaccines.