Indicator of cellular stress
Production of high levels of heat shock proteins can be triggered by exposure to different kinds of environmental stress conditions, such as inflammation, malnutrition or toxins. Hsp 70 is in particular respsonive to heat stress and cell toxines, especially heavy metals. During its presence, it protects the cell’s functionality by stabilizing new proteins to ensure correct folding or by helping to refold proteins that were damaged by the cell stress.
The Role in Cancer Patients
Heatshock proteins are overexpressed in a wide range of human cancers and are implicated in tumor cell proliferation, differentiation, invasion, metastasis, death, and recognition by the immune system. Furthermore, in contrast to normal cells, tumors frequently overexpress Hsp 70 in the cytosol, present Hsp70 on their plasma membrane, and actively release Hsp70. Elevated cytosolic levels of Hsp70 have been found to mediate protection against apoptosis, promote malignant transformation, senescence and metastatic spread, whereas extracellular, tumor-derived HSPs are considered to act as danger signals that can elicit anti-tumor immune responses.