Study On The Expression Of Related Molecules In The Process Of Drug Resistance And Reversal Of Trastuzumab In HER2 Positive Breast Cancer Cells

Objective:Using western blotting to verify the changes of HER2 receptor,ki-67,Caspase-3,integrin αvβ3,VEGF-A and PI3K/AKT pathway related proteins in HER2 positive human breast cancer cell line BT474-TS,which is sensitive to trastuzumab,and human breast cancer cell line BT474-TR,which is resistant to trastuzumab.To explore the feasibility of PI3K/AKT inhibitor LY294002 in reversing trastuzumab resistance in BT474-TR breast cancer cells,and to detect the changes of above-mentioned protein expression levels,and to understand the changes of cell proliferation and related receptor protein expression in breast cancer cell line BT474 before and after drug resistance,so as to provide a theoretical basis for nuclear medicine multimodal molecular imaging to monitor the occurrence of trastuzumab resistance.Materials and methods:Human breast cancer cell line BT474-TR,resistant to trastuzumab,was established by continuous drug induction(continuous treatment for 6 months).The inhibitory effect of trastuzumab on the proliferation of BT474-TS and BT474-TR cells in vitro was detected by cck8 assays.The expressions of HER2 receptor,ki-67,Caspase-3,integrin α v β 3,VEGF-A and PI3K/AKT pathway related proteins in BT474-TS and BT474-TR cells were detected by,Western blot assays.After the cells were treated with PI3K/AKT inhibitor LY294002,the expression of the above proteins was detected by western blot assays.Statistical software Graphpad Prism8.0was used for statistical analysis.Paired t-test was used for comparison between the two groups,and one-way ANOVA was used for comparison between the two groups.P < 0.05,it was considered that the difference was statistically significant.Results:The HER2 receptor of BT474-TS cell line was positive and located on the cell membrane by immunocytochemistry,and the RI of BT474-TS and BT474-TR cell lines was 7.62 by CCK-8 cytotoxicity test,which was moderate drug resistance.Western blotting showed that the expression of HER2 protein,Ki-67,P-AKT and VEGF-A in BT474-TS cell line was higher than that in BT474-TR cell line,and the difference was statistically significant(p= 0.0012,0.0156,0.0004,0.0015,respectively),while the expression of Caspase-3 protein was lower than that in BT474-TR cell line(p = 0.0201);Integrin α v β 3,there was no significant difference between the two cell lines.PI3K/AKT inhibitor LY294002 was used to reverse the resistance of BT474-TR to trastuzumab.The expression of Ki-67 in trastuzumab monotherapy group,LY294002 monotherapy group and double drug treatment group(trastuzumab + LY294002)was significantly lower than that in the control group(p =0.0029,0.0021,0.005,respectively).The expression of Caspase-3 in the two-drug treatment group(trastuzumab + LY294002)was higher than that in the control group and trastuzumab group(p = 0.0269 and 0.0284,respectively).Conclusion:There was a significant difference in the expression of HER2 protein,Ki-67,P-AKT,VEGF-A and Caspase-3 between HER2-positive human breast cancer cell lines sensitive to trastuzumab and drug-resistant cell lines,which provided a theoretical basis for the follow-up multimodal molecular imaging study of trastuzumab-resistant human breast cancer model.