Anti-Tumor Effects of the Polysaccharide Isolated from Tarphochlamys Affinis in H22 Tumor-Bearing Mice.

Background: The previous studies have demonstrated that the polysaccharide isolated from Tarphochlamys affinis (PTA) exhibits anti-tumor effect on S₁₈₀ tumor-bearing mice and protective effects against hepatic injury. Methods: In this study, we investigated the antitumor activity and possible underlying mechanism of PTA on liver cancer using a murine H22 hepatocarcinoma model. Results: PTA was capable of repressing transplanted H22 solid hepatic tumor cell growth in vivo. The relative weight of immune organs (spleen and thymus) and lymphocyte proliferation induced by ConA or LPS were improved after PTA treatment. Furthermore, treatment with PTA promoted immune-stimulating serum cytokine secretion in H22 tumor-bearing mice. Additionally, the percentage of CD4⁺ T lymphocytes, CD8+ T lymphocytes and NK cells was increased in tumor-bearing mice following PTA administration. In tumor tissue, PTA significantly up-regulated the expression of Bax and p53 proteins and down-regulated the expression of Bcl-2 protein. In addition, at the therapeutic dose, PTA displayed very few toxic effects to major organs, such as the liver and kidney, in tumor-bearing mice. Conclusion: In H22 tumor-bearing mice, PTA exhibited prominent anti-tumor activity in vivo. The possible mechanism of action might be related to enhanced host immune system function and induction of H22 tumor cell apoptosis. [ABSTRACT FROM AUTHOR]