Preliminary Exploration Of The Role And Mechanism Of Monacylglycerol Lipase In Triple-negative Breast Cancer

Objective:To investigate the expression of monoacylglycerol lipase（MAGL）in triple negative breast cancer（TNBC）tissues and paracancerous tissues,to analyse the correlation between the expression level of MAGL in TNBC tissues and the clinicopathological characteristics and prognosis of TNBC patients,and to apply the MAGL inhibitor JZL184 to intervene in MDA-MB-231 cells of TNBC to observe the effect on its growth.We also applied the MAGL inhibitor JZL184 to MDA-MB-231 cells of TNBC to observe the effect on their growth and further explore the mechanism of MAGL in TNBC.Methods:1.Clinical study:sixty-four pathological specimens of TNBC patients were collected and the expression levels of MAGL in TNBC tissues and paraneoplastic tissues were detected by immunohistochemistry.The relationship between MAGL expression in TNBC tissues and paraneoplastic tissues and the clinicopathological characteristics of patients was analyzed.The Kaplan-Meier method was applied to draw survival curves to analyze the correlation between MAGL expression and prognosis.2.Cellular experiments:The MAGL inhibitor JZL184 was used to intervene in triple negative breast cancer MDA-MB-231 cells,and the cell proliferation activity was detected by CCK-8 method,and the cell cycle changes were detected by flow cytometry to evaluate MAGL expression in triple negative breast cancer MDA-MB-231 cells.MDA-MB-231 cells in triple-negative breast cancer.Western blotting was used to detect the expression of ERK and Cyclin D1pathway-related cyclins in triple-negative breast cancer MDA-MB-231cells after the intervention of MAGL inhibitor JZL184.The results of the above experiments were statistically analyzed using SPSS 23.0 and Graphpad prism 9.4.0.P<0.05 was regarded as a statistically significant difference and P<0.01 was regarded as a statistically significant difference.Results:1 In TNBC tissues and paraneoplastic tissues,the positive expression rate of MAGL was 56.2%and 25.0%,respectively,and the difference in MAGL expression between the two groups was analyzed to be statistically significant（X²=18.286,P<0.05）.2 When analysing the correlation between MAGL expression levels and clinicopathological features in TNBC patients,we found that MAGL expression correlated with patient BMI and TNM stage and was statistically different（X²=10.306,P=0.023;X²=9.333,P=0.019）.3 Kaplan-Meier survival curve Log-rank univariate analysis yielded that MAGL expression,and BMI were strongly correlated with patient prognosis（Log rank=4.615,P=0.032;Log rank=4.378,P=0.036）.4 The results of CCK-8 experiment showed that MAGL inhibitor JZL184 inhibited MAGL expression and significantly inhibited the growth and proliferation of MDA-MB-231 cells,and the proliferation activity of MDA-MB-231 cells decreased with the increase of JZL184 concentration,showing a certain dose-dependent effect.The IC50 value of MAGL inhibitor JZL184 was 10.83±0.33μmol·L^-1after 48h.5 The results showed that the percentage of MDA-MB-231 cells in S-phase of the cell cycle was significantly higher than that of the control cells after MAGL inhibitor JZL184 inhibited the expression of MAGL,and the difference was statistically significant compared with the control group（P<0.05）.6 Western blotting showed that the expression levels of MDA-MB-231cell cycle-related proteins ERK and Cyclin D1 decreased gradually with time after the application of MAGL inhibitor JZL184 to inhibit MAGL expression,and the difference was statistically significant（P<0.05）.Conclusion:1 MAGL was highly expressed in TNBC tissues and low or not expressed in adjacent tissues.Positive MAGL expression in TNBC showed a positive correlation with BMI and TNM stage.2 The expression level of MAGL is negatively correlated with the patient prognosis.3 The inhibition of MAGL expression significantly inhibited the growth and proliferation of MDA-MB-231 cells,and the regulation of ERK protein through ERK/Cyclin D1 pathway blocked the cell cycle in S phase,thus affecting cell division and proliferation.