Reversal effect of Lycium barbarum polysaccharide in combination with oxaliplatin on drug resistance of colon cancer stem cells / 中国组织工程研究

ABSTRACT

BACKGROUND:Clinical treatment for colon cancer mainly includes fluorouracil,irinotecan and oxaliplatin-based therapy.Studies have shown that membrane transport proteins such as ATP-binding cassette transport protein of G2(ABCG2)mediate the transport of these drugs.However,when patients develop resistance to these chemotherapeutic drugs,the high expression of ABCG2 leads to a significant decrease in the therapeutic effect and raises the problem of drug resistance in colon cancer.New drugs and treatments are urgently needed to improve the efficacy.Lycium barbarum polysaccharide has a wide range of biological activities.It can be used as anti-tumor drug to overcome the damage to normal cells in the process of chemotherapy and radiotherapy in tumor patients. OBJECTIVE:To explore the reversal effect of Lycium barbarum polysaccharide in combination with oxaliplatin on colon cancer drug-resistant cells through in vitro experiments to investigate the possible molecular mechanism of Lycium barbarum polysaccharide reversal on colon cancer drug-resistant cells. METHODS:Colon cancer cell line HCT116 and oxaliplatin-resistant cell line HCT116-OXR were selected for in vitro experiments.The optimal intervention concentration and intervention time of Lycium barbarum polysaccharide and oxaliplatin were determined by CCK8 assay of cell proliferation.Samples were further divided into the HCT116 control group,HCT116-OXR blank treatment group,Lycium barbarum polysaccharide group(2.5 mg/mL Lycium barbarum polysaccharide),and oxaliplatin group(10 μmol/L oxaliplatin),and Lycium barbarum polysaccharide + oxaliplatin group(2.5 mg/mL Lycium barbarum polysaccharide +10 μmol/L oxaliplatin).Cell apoptosis was detected by flow cytometry.The protein expression levels of phosphomannose isomerase(PMI)and ABCG2 were detected by immunofluorescence and western blot assay.Phosphatidylinositol3-kinase(PI3K),protein kinase B(AKT),B-cell lymphoma 2(Bcl-2)and BCL2-Associated X(Bax)were detected by western blot assay. RESULTS AND CONCLUSION:(1)HCT116-OXR was more sensitive to Lycium barbarum polysaccharide compared to HCT116(P<0.05).(2)Compared with the HCT116-OXR blank group,Lycium barbarum polysaccharide + oxaliplatin could promote apoptosis of HCT116-OXR cells(P<0.05).The protein expression of Bcl-2 was significantly down-regulated(P<0.05);the protein expression of Bax was significantly up-regulated(P<0.05);the protein expression of ABCG2,PMI,PI3K and AKT was significantly down-regulated(P<0.05).(3)These results indicate that Lycium barbarum polysaccharide reverses drug resistance in colon cancer by inhibiting PMI/PI3K/AKT signaling pathway,which lays the foundation for studying the molecular mechanism of Lycium barbarum polysaccharide's sensitizing chemotherapeutic effects.