Heat shock protein 70-2 (HSP70-2) overexpression in breast cancer

Background: breast cancer is one of the leading cause of cancer-related deaths in women worldwide and increasing rapidly in developing countries. in the present study,we investigated the potential role and association of hsp70-2 with breast cancer. methods: hsp70-2 expression was examined in 154 tumor and 103 adjacent non-cancerous tissue (anct) specimens and breast cancer cell lines (mcf7,bt-474,sk-br-3 and mda-mb-231) by rt-pcr,quantitative-pcr,immunohistochemistry,western blotting,flow cytometry and indirect immunofluorescence. plasmid driven short hairpin rna approach was employed to validate the role of hsp70-2 in cellular proliferation,senescence,migration,invasion and tumor growth. further,we studied the effect of hsp70-2 protein ablation on signaling cascades involved in apoptosis,cell cycle and epithelial-mesenchymal-transition both in culture as well as in-vivo human breast xenograft mouse model. results: hsp70-2 expression was detected in majority of breast cancer patients (83 %) irrespective of various histotypes,stages and grades. hsp70-2 expression was also observed in all breast cancer cells (bt-474,mcf7,mda-mb-231 and sk-br-3) used in this study. depletion of hsp70-2 in mda-mb-231 and mcf7 cells resulted in a significant reduction in cellular growth,motility,onset of apoptosis,senescence,cell cycle arrest as well as reduction of tumor growth in the xenograft model. at molecular level,down-regulation of hsp70-2 resulted in reduced expression of cyclins,cyclin dependent kinases,anti-apoptotic molecules and mesenchymal markers and enhanced expression of cdk inhibitors,caspases,pro-apoptotic molecules and epithelial markers. conclusions: hsp70-2 is over expressed in breast cancer patients and was involved in malignant properties of breast cancer. this suggests hsp70-2 may be potential candidate molecule for development of better breast cancer treatment. © 2016 the author(s).