AST modulates the protein expression of GRP (A) and calpains (B) in tumor tissues, and inhibits tumor growth in HCT116-xenografted nude mice (C). HCT116 tumor cells (2 × 106) were injected subcutaneously to Balb/c-nu/nu mice near the right flank on day 0. Drug treatment (AST: 100 mg/kg) commenced from day 10 when tumors became palpable, and the tumor growth in xenografted animals were monitored every other day. Animals in each treatment group (n = 6-8) were sacrificed on day 24 of the experiment, when the tumor tissues were excised to assess the protein expression of GRP78, GRP94, calpain I and calpain II by using Western immunoblotting. Percentage change in tumor volume in each treatment group from day 10 to day 24 was measured and compared with respect to the volume on day 10 (100%). Representative immunoblots were obtained from independent experiments with similar findings, normalized by β-actin. Blots were scanned and optical densities were determined using the Quantity One software. The histogram represents mean ± SEM of four independent experiments. *p <0.05 and **p <0.01 compared with untreated control mice.