Heat-shock protein 70-2 (HSP70-2) expression in bladder urothelial carcinoma is associated with tumour progression and promotes migration and invasion
Received 24 July 2009; accepted 15 October 2009. published online 16 November 2009.
Abstract
Purpose
Testis specific heat-shock protein 70-2 (HSP70-2), a member of HSP70 chaperone family, is essential for the growth of spermatocytes and cancer cells. We investigated the association of HSP70-2 expression with clinical behaviour and progression of urothelial carcinoma of bladder.
Experimental design
We assessed the HSP70-2 expression by RT-PCR and HSP70-2 protein expression by immunofluorescence, flow cytometry, immunohistochemistry and Western blotting in urothelial carcinoma patient specimens and HTB-1, UMUC-3, HTB-9, HTB-2 and normal human urothelial cell lines. Further, to investigate the role of HSP70-2 in bladder tumour development, HSP70-2 was silenced in the high-grade invasive HTB-1 and UMUC-3 cells. The malignant properties of urothelial carcinoma cells were examined using colony formation, migration assay, invasion assay in vitro and tumour growth in vivo.
Results
Our RT-PCR analysis and immunohistochemistry analysis revealed that HSP70-2 was expressed in both moderate to well-differentiated and high-grade invasive urothelial carcinoma cell lines studied and not in normal human urothelial cells. In consistence with these results, HSP70-2 expression was also observed in superficially invasive (70%) and muscle-invasive (90%) patient’s tumours. Furthermore, HSP70-2 knockdown significantly suppressed cellular motility and invasion ability. An in vivo xenograft study showed that inhibition of HSP70-2 significantly suppressed tumour growth.
Conclusions
In conclusion, our data suggest that the HSP70-2 expression is associated with early spread and progression of urothelial carcinoma of bladder cancer and that HSP70-2 can be the potential therapeutic target for bladder urothelial carcinoma.
aNational Institute of Immunology, New Delhi, India
bDepartment of Urology, All India Institute of Medical Sciences, New Delhi, India
cInstitute of Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi, India
dDepartment of Pathology, Moolchand Hospital, New Delhi, India
Corresponding author: Address: Cancer Research Program, Cancer Microarray, Genes and Proteins Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India. Tel.: +91 11 26703 700; fax: +91 11 26 1621 25.
ABSTRACT