Kochia scoparia induces apoptosis of oral cancer cells in vitro and in heterotopic tumors

Abstract

Ethnopharmacological relevanceKochia scoparia grows commonly in China, Japan, and Korea and its mature fruit has been used throughout the area in traditional medicine to treat diseases including skin problems and inflammatory and allergic disease. More importantly, Kochia scoparia has been prescribed to treat the malignant tumor of head and neck region and breast mass. Although it has been proposed as an anti-cancer agent for several cancers, its exact in vivo anti-cancer properties and the molecular mechanisms underlying its effects are poorly understood. Aim of the studyTo evaluate the anti-cancer activity of the methanol extract of K. scoparia, mature fruit (MEKS) on oral squamous cell carcinoma (OSCC) and to explore its mode of action. Materials and methodsTo assess proliferation inhibition and apoptosis induction by MEKS, MTT assays, cell analysis, ANNEXIN V and PI double staining, and Hoechst 33342 staining were performed. The activation of caspases and the MAP kinase p38 was evaluated using Western blot analysis. The anti-cancer properties of MEKS in vivo were elucidated in a heterotopic OSCC animal model. ResultsAfter OSCC cells were treated with MEKS, the numbers of sub-G1 accumulated cells and apoptotic bodies increased, indicating that MEKS inhibited OSCC cell proliferation selectively through induction of apoptosis. Apoptosis of MEKS-treated OSCC cells was induced in a dose-dependent manner by caspase-3 and -9 activation. In addition, pretreatment with p38 inhibitor SB203580 in combination with MEKS significantly prevented MEKS-induced apoptosis in OSCC cells and also decreased cleaved capase 3, 9, and cleaved PARP activity in western blotting. MEKS treatment significantly increased the apoptosis of OSCC and inhibited tumour growth in our animal model. ConclusionTaken together, these results indicated that MEKS induced apoptosis of OSCC cells through caspase activation involving the p38 MAPK pathway. MEKS could be a promising anti-cancer candidate for OSCC treatment.