Curcumin treatment alters ERK-1/2 signaling in vitro and inhibits nasopharyngeal carcinoma proliferation in mouse xenografts.

Curcumin, a plant phenol, has been used for centuries in traditional medicines for its anti-inflammatory and anti-neoplastic properties. The compound is believed to act on a range of proteins involved in cell cycle regulation. In this study, the effect of curcumin on ERK-1/2 pathway protein expression and on proliferation of nasopharyngeal carcinoma cells was investigated. CNE-2Z nasopharyngeal carcinoma cells were cultured with 10, 20, 40, or 80 μM curcumin for 24 h before proliferation was assessed by MTT colorimetry. Cell proliferation was increasingly inhibited as the concentration of curcumin increased (P<0.005). Additionally, Western blotting revealed that expression of p-ERK-1/2, MMP-9, and TIMP-1 was altered following curcumin treatment, also in a dose-dependent manner. Expression of p-ERK-1/2 and MMP-9 decreased, while expression of TIMP-1 increased (P<0.05). Finally, CNE-2Z cells were xenografted under the skin of 18 nude mice. Mice were treated with vehicle only (control), 24 mg/kg curcumin (low-dose group), or 50 mg/kg curcumin (high-dose group) every other day for 40 days beginning 24 h after xenografting. Compared to tumors from the control group, the volume and weight of xenograft tumors was significantly lower in both curcumin groups, with a higher magnitude of difference in the high-dose curcumin group (P<0.05). These results indicate that curcumin treatment can inhibit proliferation of nasopharyngeal carcinoma cells and alter expression of proteins in the ERK-1/2 signaling pathway. Therefore, curcumin warrants further investigation as a potential treatment for nasopharyngeal cancer.