Metformin attenuates gefitinib-induced exacerbation of pulmonary fibrosis by inhibition of TGF-β signaling pathway

Abstract

Interstitial lung disease (ILD) is a serious side-effect of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) treatment. Therefore, it is necessary to study underlying mechanisms for the development of pulmonary fibrosis induced by EGFR-TKI and potential approaches to attenuate it. Metformin is a well-established and widely prescribed oral hypoglycemic drug, and has gained attention for its potential anticancer effects. Recent reports have also demonstrated its role in inhibiting epithelial-mesenchymal transition and fibrosis. However, it is unknown whether metformin attenuates EGFR-TKI-induced pulmonary fibrosis. The effect of metformin on EGFR-TKI-induced exacerbation of pulmonary fibrosis was examined in vitro and in vivo using MTT, Ki67 incorporation assay, flow cytometry, immunostaining, Western blot analysis, and a bleomycin-induced pulmonary fibrosis rat model. We found that in lung HFL-1 fibroblast cells, TGF-β or conditioned medium from TKI-treated lung cancer PC-9 cells or conditioned medium from TKI-resistant PC-9GR cells, induced significant fibrosis, as shown by increased expression of Collegen1a1 and α-actin, while metformin inhibited expression of fibrosis markers. Moreover, metformin decreased activation of TGF-β signaling as shown by decreased expression of pSMAD2 and pSMAD3. In vivo, oral administration of gefitinib exacerbated bleomycin-induced pulmonary fibrosis in rats, as demonstrated by HE staining and Masson staining. Significantly, oral co-administration of metformin suppressed exacerbation of bleomycin-induced pulmonary fibrosis by gefitinib. We have shown that metformin attenuates gefitinib-induced exacerbation of TGF-β or bleomycin-induced pulmonary fibrosis. These observations indicate metformin may be combined with EGFR-TKI to treat NSCLC patients.

Involvement of Lamin B1 Reduction in Accelerated Cellular Senescence during Chronic Obstructive Pulmonary Disease Pathogenesis

“…6). Previous papers demonstrating AMPK activation also used similar higher concentrations of metformin (35,36), which can be attributed to low expression levels of organic cation transporter 1, a receptor for metformin uptake (37). Accordingly, to clarify the antisenescence property, in vivo experimental models using physiological concentrations of metformin should be performed.…”

Metformin therapy associated with survival benefit in lung cancer patients with diabetes

“…The nude mice study also provided further evidence indicating that the combined treatment of metformin with the mostly common agent cisplatin for lung cancer was capable of enhancing the anti-tumor efficacy [12]. Proposed potential molecular mechanisms have been suggested for the anti-neoplastic action of metformin by some experimental data [29–32]. There was a extensively accepted mechanism of metformin action that metformin could activate the LKB1/AMPK signal axis in lung cancer cell, subsequently resulting in reduced cancer cell growth and proliferation via the suppression of mTOR activity [15].…”

Metformin Does Not Affect Clinically Relevant Outcomes in Patients with Idiopathic Pulmonary Fibrosis

“…Preclinical studies have suggested that metformin has antifibrotic and anti-inflammatory effects [23][24][25]. Metformin has been found to attenuate lung fibrosis by inhibiting transforming growth factor-beta (TGF-β) via adenosine monophosphate-activated protein kinase (AMPK) activation [26,27].…”