High level of calpain1 promotes cancer cell invasion and migration in oral squamous cell carcinoma.

Calpain1, termed conventional calpain and a member of the Ca(2+)-dependent neutral cysteine proteases, is considered to be involved in cancer formation and development. However, the effect of calpain1 on oral squamous cell carcinoma (OSCC) remains poorly understood. The aim of the present study was to evaluate the possibility of calpain1 as a potential molecular target for OSCC diagnosis and therapy. The present study demonstrates that calpain1 was overexpressed in OSCC cell lines and 4/7 of the tumor tissues in paired samples of tumor and noncancerous matched tissues (NCMT). In a cohort of 125 patients with primary OSCC, the high expression of calpain1 was an independent predictor for overall survival in a multivariate analysis (P=0.022). Furthermore, RNA interference-mediated suppression of calpain1 expression reduced the proliferation, migration and invasion potential of the HSC3 and CAL27 OSCC cell lines, but did not increase their apoptosis. These findings indicate that calpain1 may be a useful biomarker for novel prognostic and therapeutic strategies in oral squamous cell carcinoma.