Figure 5.

The Role of miR-34c on Erlotinib Resistance

(A) ER3 cells were transfected with miR-34c-3p or miR-NC. After 72 hr, transfected ER3 cells were seeded in 96-wells and treated or not with erlotinib. Cell proliferation was measured by the MTT assay 1, 2, 3, and 6 days after transfection. (B) ER3 cells were transfected with miR-34c-3p or miR-NC. After 72 hr, transfected ER3 cells were treated or not with erlotinib. Overexpression of miR-34c-3p restores sensitivity to the drug by reducing cell proliferation and colony formation. (C) Cell migration assay of ER3 cells upon miR-34c-3p and erlotinib treatment. Cells transfected with scrambled miRNA or miR-34c-3p were harvested after 72 hr and cultured on a membrane (8.0 μm pore size) inserted in the wells of a 24-well plate. Percentage of migrated cells was evaluated by eluting crystal violet solution with 1% SDS and reading the absorbance at 570 nm. Data were obtained from three independent experiments and bar graphs indicate mean value ± SD and the p value is calculated by using Student’s t test, *p < 0.05; **p < 0.01; ***p < 0.001 (over control). (D) Wound-healing assays. ER3 cells were transfected with miR-34c-3p for 72 hr and then seeded into 6-well plates at 80%–90% confluence and treated for 72 hr with GL21.T/miR-34c molecule. Bar graphs indicate mean value ± SD and the p value is calculated by using two-way ANOVA. *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001 (over control).