Abstract 2851: EGFR-TERT cooperation in the development of EGFR-TKI treatment induced pulmonary fibrosis

Abstract

Abstract Background: Previous studies have shown that epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) treatment in lung cancer can lead to the development of pulmonary fibrosis (PF). In other studies, it has been shown that reduced telomerase reverse transcriptase (TERT) function increases susceptibility to PF. In this work, we hypothesize that TERT is associated with the pathogenesis of EGFR-TKI induced PF via important signaling pathways. Methods: HCC827 cells (EGFR L858R) was treated with gefitinib and TERT expression level was detected following the treatment. To investigate the molecular changes following gefitinib treatment, we also performed a 84-TF qPCR- microarray and a qPCR microarray for 84-key secreted proteins of cytokines and chemokines. The level of interleukin-6(IL-6) was further measured with ELISA in cell medium following the gefitinib treatment. Fibrogenic markers were detected after co-culturing HCC827 with lung fibroblast IMR-90 cells. Results: TERT gene expression was significantly decreased over 90% after gefitinib treatment. Early growth response protein 1(EGR-1) and E2F transcription factor 1(E2F1) were significantly down-regulated as major TFs that are responsive to gefitinib treatment. Both EGR-1 and E2F1 have been shown to regulate TERT expression in previous studies. In addition, TFs including JUN and most REL members involved in the NF-κB pathway, were significantly up-regulated after gefitinib treatment, which are known to lead to the activation of the senescence-associated secretory phenotype (SASP) pathway. IL-6 mRNA as well as protein secretion were both significantly up-regulated after gefitinib treatment. After co-culturing HCC827 and IMR-90 for 7 days and treating with gefitinib, the growth of IMR-90 cells were increased compare to the control group. Fibrogenic markers, e.g. COL1A1 (Collagen, Type I, Alpha 1), α-SMA (alpha smooth muscle actin), FSP-1(Fibroblast-specific protein 1), etc. were all up-regulated. Conclusion: Our data suggest that EGFR inhibition leads to lung epithelial cell senescence via inhibiting TERT function and activating of the SASP pathway, which further activates fibroblasts and induces fribrogenesis. Continued studies are warranted to further understand the molecular signaling in this mechanism. Citation Format: Rongrong Wei, Wanqing Liu. EGFR-TERT cooperation in the development of EGFR-TKI treatment induced pulmonary fibrosis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2851.