Fig 2: Knockdown of miR-942-5p modulates the functional behaviors and gefitinib sensitivity of A549/GR and PC9/GR cells by up-regulating TGFBR2. A549/GR and PC9/GR cells were transfected with anti-miR-NC, anti-miR-942-5p, anti-miR-942-5p + si-NC, or anti-miR-942-5p + si-TGFBR2 and checked for TGFBR2 mRNA expression by qRT-PCR analysis (A), TGFBR2 protein level by western blot (B), IC50 value for gefitinib by MTT assay (C), cell proliferation by EdU assay (D), cell colony formation by colony formation assay (E), cell proliferation by MTT assay (F, G), cell apoptosis by flow cytometry (H), cell migration and invasion by transwell assay (I, J), Twist1 and E-cadherin levels by western blot (K, L). *P < 0.05

Fig 3: Overexpression of circ_MACF1 inhibits tumor growth under gefitinib in vivo. A qRT-PCR analysis of circ_MACF1 expression in A549/GR cells transduced by lentiviruses expressing circ_MACF1 (lenti-circ_MACF1) or a scrambled control (lenti-NC). A549/GR cells transduced by lenti-circ_MACF1 or lenti-NC were implanted into the right flanks of BALB/c nude mice (6 mice per group), with gefitinib administration (30 mg/kg) per os and tumor volume measurement (B) 10 days after implantation, and checked for tumor weight and images (C), circ_MACF1 expression by qRT-PCR analysis (D), miR-942-5p expression by qRT-PCR analysis (E), TGFBR2 mRNA level by qRT-PCR analysis (F), TGFBR2 protein level by western blot (G), TGFBR2 protein level and Ki67 staining by immunohistochemistry (H) at the end point (30 days after injection). *P < 0.05

Fig 4: Circ_MACF1 overexpression affects the functional behaviors and gefitinib sensitivity of A549/GR and PC9/GR cells by inducing TGFBR2 expression. A549/GR and PC9/GR cells were transfected with negative control Vector plasmid, circ_MACF1 overexpression plasmid, circ_MACF1 overexpression plasmid + si-NC, or circ_MACF1 overexpression plasmid + si-TGFBR2, followed by the assessment of TGFBR2 protein level by western blot (A), IC50 value for gefitinib by MTT assay (B), cell proliferation by EdU assay (C), cell colony formation by colony formation assay (D), cell proliferation by MTT assay (E, F), cell apoptosis by flow cytometry (G), cell migration and invasion by transwell assay (H, I), Twist1 and E-cadherin levels by western blot (J, K). *P < 0.05