Fig. 7. Overexpression of MEG3 promotes DDP chemoresistance and metastasis in SCLC via the miR-15a-5p/CCNE1 axis. (A) The expression of CCNE1 in NCI-H446 cells after transfection with sh-CCNE1/NC was detected by qRT-PCR. ^**p<0.01 vs. the sh-NC group. (B) The expression of CCNE1 in NCI-H446 cells after transfection with pcDNA3.1-MEG3 or pcDNA3.1-MEG3+miR-15a-5p mimics was detected by qRT-PCR. ^**p<0.01 vs. the pcDNA3.1-NC group, ^##p<0.01 vs. the pcDNA3.1-MEG3 group. (C) The viability of NCI-H446 cells transfected with pcDNA3.1-NC, pcDNA3.1-MEG3, pcDNA3.1-MEG3+miR-15a-5p mimics, or pcDNA3.1-MEG3+sh-CCNE1 under different concentrations of DDP (0, 0.625, 1.25, 2.5, 5, 10, 20, and 40 µM) was measured by MTT assay. (D) The migration of NCI-H446 cells transfected with pcDNA3.1-NC, pcDNA3.1-MEG3, pcDNA3.1-MEG3+miR-15a-5p mimics, or pcDNA3.1-MEG3+sh-CCNE1 was measured by transwell migration assay. (E) The invasion of NCI-H446 cells transfected with pcDNA3.1-NC, pcDNA3.1-MEG3, pcDNA3.1-MEG3+miR-15a-5p mimics, or pcDNA3.1-MEG3+sh-CCNE1 was measured by transwell invasion assay. ^*p<0.05, ^**p<0.01 vs. the pcDNA3.1-NC group, ^#p<0.05 vs. the pcDNA3.1-MEG3 group. SCLC, small-cell lung cancer.