Anti-tumor activity and relative mechanism of ethanolic extract of Marsdenia tenacissima (Asclepiadaceae) against human hematologic neoplasm in vitro and in vivo

Marsdenia tenacissima, a traditional Chinese medicinal herb, endemic to Yunnan Province is widely used to treat cough, asthma, expectorant, esophageal cancer, gastric cancer, lung cancer, and hepatocellular carcinoma. The aim of this study was to evaluate in vitro and in vivo anti-hematologic neoplasm potential of the ethanolic extract of this herb (crude ethanolic extract of Marsdenia tenacissima, CME) and by using different assays to elucidate its possible mechanism of action.The cytotoxicity of CME on tumor cells and peripheral blood mononuclear cells (PBMCs) was evaluated using MTT and apoptosis assays. We also tested the effect of CME on colony formation inhibition and cell cycle distribution of tumor cells. The protein expressions of Cyclin D1, Bax, Bcl-2, caspase-3 and caspase-9 were detected through Western blotting. In vivo anti-tumor effect was evaluated by measuring tumor volume changes, measuring tumor weight, evaluation of tumor microvessel density (MVD) and TUNEL staining by using immunohistochemistry staining in tumor models of nude mice.Marsdenia tenacissima ethanolic extract exhibited effects of proliferation inhibition and induction of apoptosis on human hematologic neoplasm tumor cells in vitro, as well as hematologic neoplasm growth in vivo.This study clearly indicated that the ethanolic extract of Marsdenia tenacissima displayed strong anti-tumor effects against hematologic neoplasm cells and could induce tumor cells apoptosis in vitro and in vivo, and also had a significant anti-angiogenic effect in vivo against tumor cell apoptosis. Its multi-mechanism of action might be associated with the cell cycle (G0/G1) arrest, induction of apoptosis through up-regulation protein expressions of Bax, caspase-9 and caspase-3 genes and down-regulation of the expressions of Cyclin D1 and Bcl-2 genes, a decrease in tumor microvessel density and an increase of TUNEL-positive cells in vivo. These findings provided the molecular theoretical basis of clinical application.