The Study On The Adjunct Anticancer Mechanism Of Astragalus Polysaccharide In Vivo And In Vitro

Objective:To investigate the adjunct anticancer role of Astragalus polysaccharides in H22tumor-bearing mice and H22/ADM cell lines.Methods:H22tumor-bearing mice were treated by APS and ADM intraperitoneally, after ten days of treatment, blood samples were collected from mouse eyes and serum was harvested by centrifugation. Mice were sacrificed, and the whole body, tumor, spleen, and thymus were weighed immediately. The rate of tumor inhibition and organ indexes were calculated. The expression levels of cytokines in sera and the expression levels of P-glycoprotein (P-GP) and multidrug resistance (MDR)1mRNA in tumor tissues were detected using enzyme-linked immunosorbent assay, Western blotting, and quantitative myeloid-derived suppressor cells reverse transcription-polymerase chain reaction, respectively. H22/ADM cell lines were treated with different concentrations of APS and/or the most common chemotherapy drugs, such as Cyclophosphamid, Adriamycin,5-Fluorouracil, Cisplatin, Etoposide, and Vincristine. Chemotherapeutic drug sensitivity, P-glycoprotein function and expression, and MDR1mRNA expression were detected using MTT assay, flow cytometry, Western blotting, and quantitative RT-PCR.Results:The tumor inhibition rates in the treatment groups: Adriamycin (ADM)+Astragalus polysaccharides (APS)(50mg/kg), ADM+APS (100mg/kg), and ADM+APS (200mg/kg) were significantly higher than in the ADM group. The spleen indexes of the above groups were also significantly higher than in the ADM group, and the thymus indexes of the ADM+APS (100mg/kg), ADM+APS (200mg/kg) groups were significantly higher than in the ADM group. APS was found to exert a synergistic anti-tumor effect with Adriamycin and to alleviate the decrease in the sizes of the spleen and thymus induced by AMD. The expression of interleukin-1alpha (IL-la), interleukin-2(IL-2), interleukin-6(IL-6), and tumor necrosis factor-a (TNF-a) were significantly higher in the ADM+APS (50mg/kg), ADM+APS (100mg/kg) and ADM+APS (200mg/kg) groups than in the ADM group; and interleukin-10(IL-10) was significantly lower in the above groups than in the ADM group. Results show that APS could increase IL-la, IL-2, IL-6, and TNF-a expression and decrease IL-10levels. Compared to the ADM group, APS treatment at a dose concentration of50-200mg/kg could down regulate MDRl mRNA expression in a concentration-dependent manner. The expression level of P-GP was significantly lower in the ADM+APS (200mg/kg) group than in the ADM group.When used alone, APS had no anti-tumor activity in H22/ADM cells in vitro. However, it can increase the cytotoxicity of certain chemotherapy drugs, such as Cyclophosphamid, Adriamycin,5-Fluorouracil, Cisplatin, Etoposide, and Vincristine, in H22/ADM cells. It acts in a dose-dependent manner. Compared to a blank control group, APS increased intracellular Rhodamine-123retention and decreased P-glycoprotein efflux function in a dose-dependent manner. These factors were assessed24h,48h, and72h after administration. APS down regulated P-glycoprotein and MDR1mRNA expression in a concentration-dependent manner within a final range of0.8-500mg/L and in a time-dependent manner from24-72h.Conclusion:The adjunct anticancer mechanism of astragalus polysaccharide in vivo and in vitro may be related to its ability to increase expression of IL-la, IL-2, IL-6, and TNF-a, decrease IL-10, and down regulate MDR1mRNA and P-GP expression levels.