YAP inhibitor, Verteporfin (VP) suppresses the cell proliferation of EGFR‐TKI‐resistant PC9/GR. (A) CCK assay of PC9/GR cells after treatment of 5 μM gefitinib or 25 μM CQ with YAP siRNA#1 or siRNA #2. Left and right panels are the results of 6 and 24 h treatments, respectively. (B) Western blot analysis of YAP and p62 in PC9 and PC9/GR cells after treatment of VP for 24 h (0, 2, and 5 μg/ml, respectively). VP significantly decreased the expression of YAP, its target PD‐L1, and p62. (C) Western blot analysis of YAP and p62 with partial p62 oligomerization in PC9/GR cells after treatment of VP for 24 h (0, 2, and 5 µg/ml, respectively). (D) Western blot analysis of YAP, PD‐L1, p62, PARP, and C‐PARP in PC9/GR cells after combination treatment of gefitinib (10 μM) with VP (2.5 μg/ml) or chloroquine(25 μM) for 6 h. (E) Cell viability was assessed by CCK assay in PC9/GR cell after combination treatment of gefitinib (10 μM) with VP (2.5 μg/ml) or chloroquine (25 μM) for 6 h. ***p < 0.005 (Student's t‐test)