Effective inhibition of a Strongylocentrotus nudus eggs polysaccharide against hepatocellular carcinoma is mediated via immunoregulation in vivo

Abstract

This study was aimed at evaluating the inhibitory effect of a polysaccharide that was isolated from Strongylocentrotus nudus eggs (SEP) against hepatocellular carcinoma in H22-bearing mice and elucidating its immunological mechanisms by determining its effects on the growth of transplanted tumors and immune response in H22-bearing mice. ICR mice inoculated with mouse hepatoma carcinoma cell lines H22 were treated with SEP at doses of 4, 8, 16mg/kg/d for 12days. The effects of SEP were measured via the growth of the transplanted tumors, splenocyte proliferation, T lymphocytes counts, CTL activity, the production of cytokines from splenocytes and the levels of serum Ig in tumor-bearing mice. In addition, the effects of SEP on Erk phosphorylation in mouse splenocytes and on the transcriptional activity of NFAT in Jurkat T cells were also investigated. Our results showed that SEP significantly inhibited the growth of transplanted tumors in mice. SEP could not only remarkably enhance splenocyte proliferation, CD4+ and CD8+ T cell numbers as well as CTL activity, but it also elevated IL-2 and TNF-α secretion as well as IgA, IgM and IgG levels in the serum. Furthermore, the activation of Erk phosphorylation and the NFAT promoter by SEP promoted the transcription and expression of downstream gene IL-2. In conclusion, our study demonstrates that SEP effectively inhibits hepatocellular carcinoma in vivo via enhancement of host immune system function, and it could be a potential therapeutic drug for hepatocarcinoma.