Actinidia eriantha Polysaccharide and PD1-Antibody Combination Therapy Enhances Antitumor Efficacy in Colorectal Cancer-Xenograft Mice.

Objective To observe the efficacy of Actinidia eriantha polysaccharide (AEPS) combined with PD1 antibody therapy in colorectal cancer-xenograft mice. Methods CT26 cells were inoculated into 80 C57BL/6 mice to establish the colorectal cancer xenograft-mouse model. Mice were divided evenly into a model group, AEPS group, anti-PD1 group, and combined group. AEPS 5mL/kg•day was given orally and 10 mg/kg anti-PD1 injected intravenously for 28 days. Tumor growth and mouse survival were observed. Tumor-cell proliferation and metastasis markers Ki67, N-cadherin, KLF4, and Oct4 were detected with immunochemistry and Western blotting, T-cell infiltration in spleens and tumors was detected with MTT and flow cytometry. IFNγ and TNFα were detected with ELISA. Results Tumor growth was significantly retarded and survival prolonged in the AEPS, anti-PD1, and combined groups. Ki67 expression decreased in the anti-PD1 and combined groups, and N-cadherin, KLF4, and Oct4 expression decreased in the AEPS and combined groups. IFNγ and TNFα levels, T-cell infiltration in spleen, and tumor all increased distinctively in the AEPS and combined groups. The combined group showed better antitumor effects and life-extension effect than the other two groups. Conclusion AEPS and PD1 antibody-combination therapy can suppresses tumor growth and prolong survival of colorectal cancer-xenograft mice by regulating immunofunction, and the combined therapy showed better therapeutic efficacy than the single treatment.