Research Paper Volume 14, Issue 7 pp 3105—3128

Figure 4. MiR-885-3p suppressed the proliferation of breast cancer and targeted NTRK2 to affect the PIK3CA/AKT signaling pathway. (A) The transfection efficiency of miR-885-3p mimics in MDA-MB-231 and MCF-7 cells. (B, C) MTT assays of both cell lines showed that the proliferation was inhibited by overexpression of miR-885-3p. (D) Colony formation assays showed that overexpression of miR-885-3p suppressed both cellular colony-forming capacities. (E) The migration and invasion of MDA-MB-231 cells were suppressed after overexpressing miR-885-3p. (F) Histogram of the percentage of cell cycle distribution of G0/G1, S, and G2/M phases with overexpression of miR-885-3p in both breast cancer cells; miR-885-3p could arrest both cells in G0/G1 phase. (G) Protein levels of CDK2, CCNE1, CDK4, CDK6, CCND1, and PCNA in MDA-MB-231 and MCF-7 cells decreased after increasing the expression of miR-885-3p. (H, I) Columns were used to quantify the cell cycle protein expression levels in (I) relative to β-actin. (J) The predicted wild-type binding sites and designed mutant-type binding sites of miR-885-3p and NTRK2. (K, L) Dual-luciferase reporter assays conducted in HEK293T and MDA-MB-231 cells with miR-885-3p and NTRK2 suggested that miR-885-3p decreased the relative activity of luciferase reporters of the wild-type group. (M) Relative expression of NTRK2 decreased in the MDA-MB-231 and MCF-7 cells overexpressing miR-885-3p. (N) The protein levels of NTRK2, PIK3CA, and p-AKT decreased in the two cell lines treated with miR-885-3p mimics, while those of AKT remained unchanged. (O, P) Columns were used to quantify the protein expression levels relative to β-actin. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001.