Modified Shenlingbaizhu decoction reduces intestinal adenoma formation in adenomatous polyposis coli multiple intestinal neoplasia mice by suppression of hypoxia-inducible factor 1α-induced CD4+CD25+forkhead box P3 regulatory T cells

Objective: To test the hypothesis that modified Shenlingbaizhu decoction (MSD) attenuates the formation of intestinal adenomas by regulating activation of CD4+CD25+ forkhead box P3 (FoxP3) regulatory T cells (Tregs) by downregulation of hypoxia-inducible factor 1α (HIF-1α).

Methods: Chemical fingerprints of ginsenoside Rb1, ginsenoside Rc, paeoniflorin, and dioscin in standard extractions were used as material bases of MSD. Adenomatous polyposis coli multiple intestinal neoplasia (ApcMin/+) mice, which harbor a mutation in adenomatous polyposis coli, were used to host intestinal adenomas. Peripheral blood and spleen Tregs were analyzed by flow cytometry. Protein expression was analyzed by immunohistochemistry and Western blotting.

Results: The number and size of intestinal adenomas were significantly reduced by MSD treatment. Mucosal thickening and the spleen size were also substantially decreased by MSD. The carcinogenesis process in ApcMin/+ mice resembled that of human colorectal cancer. Molecular markers of neoplasms, such as β-catenin, cyclooxygenase-2, proliferating cell nuclear antigen, and p53, were substantially ameliorated by MSD treatment. Moreover, MSD downregulated peripheral and spleen CD4+CD25+FoxP3+ Tregs and reduced in situ expression of CD4, CD25, and FoxP3 in intestinal adenomas. MSD also suppressed HIF-1α expression in the intestinal adenomas, and HIF-1α inhibition decreased expression of FoxP3 in Jurkat T cells under hypoxic conditions.

Conclusion: MSD is a valid prescription to control the formation of intestinal adenomas in ApcMin/+ mice. It exerts anti-cancer effects partially through suppression of HIF-1α that induced activation of CD4+CD25+FoxP3+ Tregs in vivo and in vitro.