Metformin synergistically enhances the antitumor activity of the third‐generation EGFR‐TKI CO‐1686 in lung cancer cells through suppressing NF‐κB signaling

• Published in: The clinical respiratory journal 2018-12, Vol.12 (12), p.2642-2652
• Main Authors: Pan, Yong‐Hong, Lin, Cai‐Yu, Lu, Cong‐Hua, Li, Li, Wang, Yu‐Bo, Chen, Heng‐Yi, He, Yong
• Format: Article
• Language: English
• Subjects: acquired resistance; Antidiabetics; CO‐1686; Kinases; Lung cancer; metformin; NF‐κB; Proteins
• ISSN: 1752-6981; 1752-699X
• DOI: 10.1111/crj.12970

Purpose Third‐generation irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR‐TKI), rociletinib (CO‐1686), is great efficacy against EGFR‐mutated patients bearing the T790M resistance mutation. However, acquired resistance may emerge. There is a need to characterize acquired resistance mechanism(s) and to devise ways to overcome CO‐1686 resistance. Experimental Design MTT assay, ki67 incorporation assay, transwell assay and TUNEL assay were employed to analyze the effects of metformin to reverse CO‐1686 resistance in vitro. The NF‐κB activity was measured by the antibody of p50, p65, p‐IKBɑ, and p‐IKKɑ/β. Western blotting was used to analyze the proteins in cells. Results We have established CO‐1686‐resistant cell lines of PC‐9GRCOR and H1975COR from two parental cell lines of PC‐9GR and H1975 by long‐term exposure to increasing doses of CO‐1686. Compared with the parental cells, PC‐9GRCOR cells and H1975COR cells showed 90‐folds and 20‐folds higher resistance to CO‐1686, respectively. Critically, we showed that the nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB) signaling molecular proteins subunits of p50, p65 and its inhibitor proteins of IKBɑ, IKKɑ/β in phosphorylation levels in resistant cells were higher than parental cells. Accordingly, inhibition of NF‐κB activity used TPCA‐1 effective in decreasing viability and inducing apoptosis of resistant cells. Moreover, metformin overcame the acquired resistance to CO‐1686 by reducing cell proliferation and invasion. Metformin combined with CO‐1686 synergistically inhibited the p‐IKBɑ, p‐IKKɑ/β, p50, and p65. Conclusions NF‐κB signaling activation induced acquired resistance to CO‐1686. Metformin sensitized resistant cells to CO‐1686 via inhibiting NF‐κB signaling.