The HSP70 family of heat shock proteins consists of molecular chaperones of approximately 70 kDa in size that serve critical roles in protein homeostasis. These ATPases unfold misfolded or denatured proteins, and can keep these proteins in an unfolded, folding-competent state. They also protect nascently-translating proteins, promote the cellular or organellar transport of proteins, reduce proteotoxic protein aggregates, and serve general housekeeping roles in maintaining protein homeostasis. The HSP70 family is the most conserved in evolution, and all eukaryotes contain multiple members. Some members of this family serve specific organellar- or tissue-specific functions; however, in many cases these members can function redundantly. Overall, the HSP70 family of proteins can be thought of as a potent buffering system for cellular stress, either from extrinsic (physiological, viral, environmental) or intrinsic (replicative or oncogenic) stimuli. As such, this family serves a critical survival function in the cell. Not surprisingly cancer cells rely heavily on this buffering system for survival. The overwhelming majority of human tumors overexpress HSP70 family members, and expression of these proteins is typically a marker for poor prognosis. With the proof of principle that inhibitors of the HSP90 chaperone have emerged as important anti-cancer agents, intense focus has now been placed on the potential for HSP70 inhibitors to assume a role as a significant chemotherapeutic avenue. In this review, the history, regulation, mechanism of action, and role in cancer of the HSP70 family is reviewed. Additionally, the promise of pharmacologically-targeting this protein for cancer therapy is addressed.
"Although the role of APA in modulating Hsp70.3 expression has not been as well explored, HuR has been previously suggested to regulate Hsp70 levels in renal I/R injury . Interestingly , the development of many human tumors is also associated with HuR activation and overexpression of Hsp70   . "
"A phenomenon potentially governed by differences in the mechanisms of tumor cell death induced by fractionated versus single dose radiation therapy. Notably in p53 mutated and wildtype glioblastoma cell lines fractionated radiotherapy was reported to promote the release of HSP70 , which has been shown to signal DC activation . Interestingly, gene expression profiling of in vitro irradiated breast, prostate and glioma tumor cells also revealed that genes regulating immune (e.g. "
"Hsps can promote tumorigenesis and the prevention of tumor cell apoptosis -. The amount of Hsp expression in these malignant tumors seemed to correlate with the aggressiveness of the tumors  . However, there was no report of Hsp expression in giant cell tumor of bone from our literature reviews. "
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