Osthole promotes anti-tumor immune responses in tumor-bearing mice with hepatocellular carcinoma

Osthole, a natural coumarin derivative, has been shown to have anti-tumor and anti-inflammatory activity. However, the effect of osthole on anti-tumor immune responses in tumor-bearing mice has not yet been reported. In the present study, osthole treatment did not affect the weight and the coefficient of thymus and spleen in tumor-bearing mice with hepatocellular carcinoma (HCC). However, osthole administration significantly elevated the proportion and number of the splenic CD8+ T cells, the proportion of CD4+ T and CD8+ T cells in tumor tissues, and the levels of IL-2 and TNF-α in the serum of HCC tumor-bearing mice. Our results suggested that osthole could promote the activation of the tumor-infiltrating CD4+ T and CD8+ T cells, and elevate the proportion of CD4+ and CD8+ effector T cells. Osthole treatment also significantly decreased the proportion of CD4+CD25+Foxp3+ regulatory T cells in the spleen. Taken together, osthole could enhance the T cell mediated anti-tumor immune responses in the tumor-bearing mice with HCC.