Abstract:
Objective To explore the mechanism by which breast cancer-derived LncRNA OIP5-AS1 regulates the migration, invasion, and epithelial-mesenchymal transition of breast cancer cells through the M2 polarization of tumor-associated macrophages (TAM).
Methods MDA-MB-231 cells were divided into the control group (blank control), the NC group (transfected with NC siRNA), and the si-OIP5 group (transfected with LncRNA OIP5-AS1 siRNA). The mRNA expression levels of LncRNAs OIP5-AS1, IL-4, and IL-13 were detected by RT-qPCR. The protein expression levels of IL-4 and IL-13 in the culture supernatant were detected by ELISA. The culture supernatant from the control group was added to RPMI 1640 medium at different volume ratios to induce the polarization of M0 macrophages into TAMs. The mRNA expression of CD206 in TAMs was detected by RT-qPCR. M0-type macrophages were induced with the medium supernatant of the NC group/si-OIP5 group, and the expression of CD206 was detected by Western blot. Subsequently, a co-culture model of macrophage and MDA-MB-231 was constructed to evaluate the migration and invasion abilities of MDA-MB-231 cells and detect the expression changes in Vimentin, N-cadherin and E-cadherin.
Results Compared with the control and NC groups, the si-OIP5 group showed significantly downregulated expression of LncRNA OIP5-AS1 (P<0.001) and significantly decreased IL-13 mRNA and protein levels (P<0.05). Meanwhile, no significant difference was observed in the expression of IL-4 among the groups. Conditioned medium induced CD206 expression in M0 macrophages in a volume-dependent manner, with the strongest effect at a 40% volume ratio (P<0.001). The CD206 protein level in the si-OIP5 group significantly decreased (P<0.01). In the co-culture system, the migration and invasion abilities of MDA-MB-231 cells in the si-OIP5 group significantly weakened (P<0.001), the expression of E-cadherin was upregulated, and the expression levels of N-cadherin and Vimentin were downregulated (both P<0.01).
Conclusion Breast cancer-derived LncRNA OIP5-AS1 can induce TAM M2 polarization mediated by IL-13, thereby promoting the migration, invasion, and EMT of breast cancer cells.