Heat shock Proteins (HSPs) play essential role in cellular homeostasis and
therefore, maintain key proteins at their native state against cellular stress to promote
cell survival. ATP independent HSP27 makes a defense against stress factors to
facilitate ATP dependent Hsp machinery to perform its function under stress conditions.
The machinery involves HSP70, HSP40, HSP60, HSP90, and HSP100 proteins. The
expression of inducible HSP27 is at basal levels in normal cells; however, HSP27 is
abnormally expressed in breast cancer, ovarian cancer, osteo-sarcoma, endometrial
cancer, and leukemia cells. Elevated HSP27 in oncogenic cells resists anti-cancer
therapy since it protects the cell against spontaneous apoptosis. Furthermore, HSP27
inhibits apoptotic signals at regulatory points which may explain the role of HSP27 in
tumor progression and resistance to therapy. Phosphorylation and oligomerization of
HSP27 regulate its biochemical function. Recent literature reports on HSP27 structure,
function, and its role in oncogenesis and apoptosis are discussed in this review.
Keywords: Apoptosis, Cancer, Heat Shock protein 27, Protein folding.
