Targeting the testis-specific heat-shock protein 70-2 (HSP70-2) reduces cellular growth, migration, and invasion in renal cell carcinoma cells

Abstract

Renal cell carcinoma (RCC) represents one of the most resistant tumors to radiotherapy and chemotherapy. Current therapies for the RCC patients are limited owing to lack of diagnosis and therapeutic treatments. Testis-specific heat-shock protein 70-2 (HSP70-2), a member of HSP70 chaperone family, has been shown to be associated with various cancers. In the present study, we investigated the putative role of HSP70-2 in various malignant properties of the RCC cells. HSP70-2 messenger RNA (mRNA) and protein expression was investigated in A704, ACHN, and Caki-1 cells derived from the RCC patients. We assessed the expression of HSP70-2 gene and protein by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively. The expression of HSP70-2 protein was further validated by performing indirect immunofluorescence (IIF) and flow cytometry. The malignant properties of high-grade invasive A704 and Caki-1 cells, such as cellular proliferation, colony formation, migration, invasion, and wound healing, were evaluated by silencing the expression of HSP70-2 gene in these cells. Statistical significance was defined using Student's t test. Our RT-PCR and Western blotting data showed the expression of HSP70-2 in all RCC cells. Our results showed that HSP70-2 was predominantly expressed in cytoplasm and found to be colocalized with endoplasmic reticulum, mitochondria, Golgi body, and plasma membrane but not the nuclear envelope. Knockdown of HSP70-2 expression with specific short hairpin RNA (shRNA) demonstrated significant reduction in cell growth and colony formation. Further, a marked reduction in cell migration and invasion was also observed, indicating the potential role of HSP70-2 in metastasis. Collectively, our data suggest that HSP70-2 plays a key role in cancerous growth and invasive potential of RCC cells. Thus, HSP70-2 could serve as a novel potential therapeutic target for the RCC.

Let-7c miRNA Inhibits the Proliferation and Migration of Heat-Denatured Dermal Fibroblasts Through Down-Regulating HSP70

“…However, upon heat shock, we identified an approximately 5-fold and 2-fold increase in HSP70 at the mRNA and protein levels, respectively in the let-7c inhibitor-transfected fibroblasts compared with the untransfected controls, suggesting an important role of let-7c in regulating HSP70 upon heat shock. Furthermore, the knockdown of HSP70 expression significantly attenuated and reversed the enhanced proliferation and migration induced by the let-7c inhibitor, in agreement with earlier research showing that HSP70 promotes cell proliferation and viability in cancer cells ( Singh and Suri, 2014 ).…”

Upregulation of heat shock protein 70 and the differential protein expression induced by tumor necrosis factor-alpha enhances migration and inhibits apoptosis of hepatocellular carcinoma cell HepG2

“…Similarly, we observe that TNFα upregulates HSP70 expression level, contributing to promoted cell migratory ability and suppressed apoptosis of HepG2 cell. Thus, we propose that silencing HSP70 may increase sensitivity to the antitumor drug for HCC cells as previously described for other malignancies 38, 39. Overexpression of HSP90 has been observed in several types of tumors such as acute myeloid leukemia and is linked with poor prognosis 33, 34, 40.…”

The Cytotoxicity of Kahweol in HT-29 Human Colorectal Cancer Cells Is Mediated by Apoptosis and Suppression of Heat Shock Protein 70 Expression

“…It has been reported that HSPs are often overexpressed in tumors and promote their growth ( Grivicich et al ., 2007 ; Kim et al ., 2013 ; Singh and Suri, 2014 ). Especially, HSP70 is often constitutively overexpressed in human colorectal cancer cells ( Grivicich et al ., 2007 ; Kim et al ., 2013 ), and high expression of HSP70 is associated with resistance to chemotherapy ( Sarto et al ., 2000 ; Garrido et al ., 2001 ; Takayama et al ., 2003 ).…”

“…Especially, HSP70 is often constitutively overexpressed in human colorectal cancer cells ( Grivicich et al ., 2007 ; Kim et al ., 2013 ), and high expression of HSP70 is associated with resistance to chemotherapy ( Sarto et al ., 2000 ; Garrido et al ., 2001 ; Takayama et al ., 2003 ). Furthermore, knockdown of HSP70 exhibited significant reduction in cell growth ( Singh and Suri, 2014 ). Both in vivo and in vitro animal studies showed that inhibition of HSP70 has antitumor effect against colon cancer ( Gurbuxani et al ., 2001 ; Schmitt et al ., 2006 ).…”