Expression of miR-211-5p in peripheral blood of patients with myelosuppression after neoadjuvant chemotherapy for breast cancer and its regulatory mechanism in Notch signaling pathway / 中华内分泌外科杂志

ABSTRACT

Objective:To investigate the expression of miR-211-5p in peripheral blood of patients with myelosuppression after neoadjuvant chemotherapy for breast cancer and its effect on Notch signaling pathway by targeting cyclooxygenase 2 (COX2) gene Regulation mechanism.Methods:From Jan. 2018 to Jan. 2021, 185 breast cancer patients who received neoadjuvant chemotherapy in Linyi People’s Hospital for the first time were included as the research objects. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure the mRNA expression levels of miR-211-5p, COX2 gene and Notch signaling pathway related genes (Notch1, Jagged1 and Hes1) . The miR-211-5p mimic, inhibitor, mimic NC, and inhibitor NC were transfected into SD rat bone marrow mesenchymal stem cells, and the mRNA expression of miR-10a-3p and COX2 genes was detected by qRT-PCR for 48 hours. Western blot method was used to detect the protein expression levels of Notch signaling pathway related genes.Results:The relative expression of miR-211-5p in patients with severe myelosuppression was 2.41±0.32, which was significantly higher than that in patients with mild myelosuppression (1.53±0.18) ( t=6.385, P<0.001) ; The relative expression of COX2 gene mRNA in patients with severe myelosuppression was 3.64±0.74, which was significantly lower than that in patients with mild myelosuppression (5.37±1.02) ( t=7.469, P<0.001) . In patients with severe myelosuppression, there was a significant negative correlation between miR-211-5p and COX2 gene mRNA levels ( r=-0.694, P=0.006) . The results of the dual luciferase report experiment confirmed that COX2 was the target gene of miR-211-5p. The relative expression of Notch1, Jagged1, and Hes1 mRNA in peripheral blood of patients with severe myelosuppression were 2.35±0.41, 2.76±0.46 and 3.04±0.52, respectively, which were significantly lower than those in patients with mild myelosuppression (4.12±0.63, 4.53±0.58 and 5.12±0.67) ( t=5.367, 6.114 and 6.135, respectively, P<0.001) . After transfecting SD rat bone marrow mesenchymal stem cells with miR-211-5p mimics and inhibitors, the relative expression of miR-211-5p in the mimic group was 3.46±0.49, significantly higher than that in the mimic NC group (2.24±0.32) The relative expression of miR-211-5p in the inhibitor group was (1.28±0.19) and (2.33±0.37) inhibitor NC group ( P<0.001) , while the relative expression of miR-211-5p in the inhibitor group was significantly lower than that in the other three groups ( P<0.001) . The mRNA expression of COX2 gene in mimic group was 2.73±0.36, which was significantly lower than that in mimic NC group (4.05±0.59) , inhibitor group (6.15±0.86) and inhibitor NC group (4.18±0.65) ( P<0.001) , while mRNA expression of COX2 gene in the inhibitor group was significantly higher than that in the other three groups ( P<0.001) . The expression of Notch1, Jagged1, and Hes1 in the inhibitor group was significantly increased, while the expression of Notch1, Jagged1, and Hes1 in the mimic group was significantly decreased. Conclusion:The expression level of miR-211-5p in peripheral blood of severe myelosuppressed patients with breast cancer after neoadjuvant chemotherapy is significantly increased, and the Notch signaling pathway can be inhibited by targeted down-regulation of COX2 gene expression.