Abstract
Cassia tora L. (Jue-ming-zi) is a traditional Chinese medicine widely used in East Asia. The in vitro anticancer effects of Jue-ming-zi were evaluated in TCA8113 human tongue carcinoma cells using a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay. At a concentration of 1.0 mg/ml, Cassia tora L. inhibited the growth of TCA8113 cells by 72%; this inhibiton was greater than that by 0.5 and 0.25 mg/ml Cassia tora L. (43 and 16%, respectively). To elucidate the inhibitory mechanisms underlying the anticancer effect of Cassia tora L. in cancer cells, the expression of genes associated with apoptosis, inflammation and metastasis were measured using RT-PCR and western blot analysis. Cassia tora L. significantly induced apoptosis in cancer cells (P<0.05) by upregulating Bax, caspase-3 and caspase-9, and by downregulating Bcl-2. The expression of genes associated with inflammation, including NF-κB, iNOS and COX-2, was significantly downregulated (P<0.05) by Cassia tora L., demonstrating its anti-inflammatory properties. Cassia tora L. also exerted a significant anti-metastatic effect on cancer cells as demonstrated by decreased mRNA expression of matrix metalloprotease (MMP) genes and increased expression of tissue inhibitors of metalloproteinases (TIMPs), and as confirmed by the inhibition of induced tumor metastasis induced in 26-M3.1 colon cells in BALB/c mice. Our results demonstrated that Cassia tora L. exhibited the most potent in vitro anticancer effects, induced apoptosis, had anti-inflammatory activities and exerted in vivo anti-metastatic effects. Additionally, the anticancer, anti-inflammatory and anti-metastatic effects of the higher Cassia tora L. concentrations were stronger compared with those of the lower Cassia tora L. concentrations tested.