Study On The Effect And Mechanism Of Protopanaxadiol In Reversing Paclitaxel Resistance In MDA-MB-231

Objective: The purpose of this study was to investigate the effect of propanaxadiol(PPD)on the activity and apoptosis of MDA-MB-231 paclitaxel-resistant(PTX)cells(MB231-PR)in vitro,and to explore its possible molecular mechanism,so as to provide a new direction for the treatment of clinical Triple Negative Breast Cancer(TNBC).Methods: 1.The activity of PPD on MB231-PR cells and the effect of PPD combined with PTX on the viability of MB231-PR cells were detected by Cell Titer-Glo method,and the effect of PPD combined with PTX on cell proliferation was observed by cell clone formation assay.2.Flow cytometry was used to detect the effect of PPD combined with PTX on MB231-PR cell cycle.3.The effects of different drugs on the m RNA expression of ZEB1,ZEB2,SNAIL,SLUG,VIM,CDH1,TWIST1,TWIST2,ALDH1 and CD44 in MB231-PR cells were detected by RT-q PCR method.4.Tumor ball formation test was used to observe the effect of PPD combined with PTX on tumor ball formation ability of MB231-PR cells.5.Western Blot was used to detect the expression of apoptotic proteins Bax,Bcl-2,cPARP and NF-κ B,P38-MARK signal pathway proteins P38,p-P38,p65 and p-P65 by PPD combined with PTX.Results: 1.Cell Titer-Glo results showed that PPD inhibited the viability of MB231-PR cells in a dose-dependent manner,and the IC 50 value of PPD on MB231-PR cells was 23.26μM.Compared with the PTX group,PPD combined with PTX group could significantly inhibit the viability of MB231-PR cells in a time-and concentrationdependent manner.The colony formation assay showed that PPD combined with PTX group could significantly inhibit the colony formation of MB231-PR cells compared with the PTX group.2.The results of flow cytometry showed that compared with PTX group,PPD combined with PTX group significantly increased the accumulation of sub G1 phase cells,and Western Blot results showed that compared with PTX group,PPD combined with PTX group significantly increased the expression of c-PARP and Bax/Bcl-2 protein in a concentration-dependent manner(P < 0.05).3.RT-q PCR results showed that compared with PTX group,PPD combined with PTX group could significantly inhibit the expression of ALDH1,CD44,ZEB1,ZEB2,SLUG and VIM at 48 h(P < 0.05).There was no significant change in the expression of SNAIL(P < 0.05)4.The results of tumor formation assay showed that compared with PTX group,PPD combined with PTX group could inhibit the growth of MB231-PR tumor spheres and kill cancer cells at the same time.5.Western Blot results showed that compared with PTX group,PPD combined with PTX group could increase the phosphorylation of P65 and P38 protein(P < 0.05).Conclusion: 1.PPD has a toxic effect on MB231-PR cells in a dose and time-dependent manner,and PPD combined with PTX has a synergistic inhibitory effect on cell proliferation.2.The enhancement of the inhibitory effect of PPD combined with PTX on proliferation may be achieved through the accumulation of sub G1 phase cells and induction of apoptosis.3.PPD combined with PTX can reduce the expression of EMT and breast cancer stem cell markers,and inhibit the ball-forming ability of cells,thus inhibit the occurrence of EMT and reverse drug resistance.4.PPD combined with PTX can activate P65 and P38-MAPK signal pathway.