Ganoderma Lucidum Polysaccharides Suppress The Malignant Phenotype Of Breast Cancer By Regulating The Expression Of Antioxidant Factors

Objective The effect of Ganoderma lucidum polysaccharide(GLP)on the growth and apoptosis of MCF-7 and MDA-MB-231 breast cancer cells and its molecular mechanism were investigated.Methods1.Effect of GLP on the malignant progression of breast cancer In the experiment,MCF-7 and MDA-MB-231 breast cancer cells were treated with different concentrations of GLP to select the appropriate concentration for further experiments.MTS method was used to detect the effect of GLP on the growth and proliferation of breast cancer cells.TUNEL staining and AV-PI flow cytometry were used to detect the effect of GLP on the apoptosis of breast cancer cells.2.The molecular mechanism of GLP in regulating apoptosis of breast cancer cells The cellular levels of reactive oxygen species(ROS)were measured using a flow cytometry assay,while the levels of intracellular glutathione(GSH)were assessed using a GSH detection kit.The study employed RT-PCR technology to detect the m RNA expression of antioxidant-related genes,including glutamate-cysteine ligase regulatory subunit(GCLM),glutamate-cysteine ligase catalytic subunit(GCLC),human thioredoxin reductase 1(TXNRD1),malic enzyme 1(ME1),and thioredoxin(TXN).In addition,Western blotting was utilized to detect the protein expression of GCLM and TXNRD1.Results1.GLP inhibited the growth and proliferation of breast cancer cells and promoted apoptosis of breast cancer cells(1)The results obtained from the MTS assay indicate a significant decrease in the activity of breast cancer cells in the GLP-treated group as compared to the control group.(P<0.01).(2)Tunel staining showed that GLP-treated MDA-MB-231 or MCF-7 cells exhibited a dramatic increase in the proportion of apoptosis.(P<0.05,P<0.01).(3)Flow cytometry results obtained from AV-PI analysis showed that both early and late apoptosis rates were increased in the GLP-treated group compared with the control group.Specifically,the early apoptosis rate was more pronounced in MCF-7cells,while the late apoptosis rate was more evident in MDA-MB-231 cells.(P<0.05,P<0.01).2.GLP induced apoptosis in breast cancer cells by regulating the levels of antioxidant-related genes and proteins(1)The results of ROS assay showed that the intracellular ROS level was significantly increased after GLP treatment.(P<0.05,P<0.01).(2)The results of GSH assay showed that the total intracellular GSH level was significantly decreased after GLP treatment.(P<0.01).(3)RT-PCR results showed that the GLP incubation can lead to a decreased m RNA level of GCLM,GCLC,TXNRD1,ME1 and TXN in both MCF-7 and MDA-MB-231 cells except for TXN level in MDA-MB-231 cells.(P<0.05,P<0.01).(4)Western blotting displayed that the glucose treatment cells with GLP contained obviously a decreased concentration of GCLM and TXNRD1 expression levels compared to the control group.(P<0.05,P<0.01).Conclusion.1.GLP can inhibit the growth and proliferation and promote apoptosis of breast cancer cells.2.Through regulating the expression of antioxidant genes,GLP inhibited GSH production in breast cancer cells,promoted intracellular ROS accumulation and eventually induced apoptosis.