Abstract 2842: 5-aza-2’-Deoxycytidine induces cellular senescence in non-small cell lung cancer

Abstract Background: Lung cancer is one of the refractory malignancies and the leading cause of cancer-related death worldwide. Although prognosis of lung cancer was improved by the anticancer drugs and molecular targeted therapies, the results are not sufficient. Cellular senescence is irreversible cell cycle arrest. The drug-dependent induction of cellular senescence in neoplastic cells is considered an important tumor suppressive mechanism. 5-aza-2’-deoxycytidine (5-aza-dC) causes cellular senescence in solid tumors. Hypermethylation of CpG islands is well known as a major inactivation mechanism of tumor suppressor genes such as E-cadherin. Loss of E-cadherin confers a poor prognosis in lung cancer patients and is associated with in vitro resistance to epidermal growth factor receptor inhibitors. This study was designed to assess the relationship of E-cadherin expression cellular senescence induced by 5-aza-dC in non-small cell lung cancer (NSCLC) cell lines. Materials and Methods: We investigated two NSCLC cell lines; H1299 and A549 reported they have hypermethylation in promoter lesion of E-cadherin. There are two clinically approved DNA methyltransferase inhibitors (DNMTi), 5-aza-dC and 5-azacytidine (5-aza-CR). We also used Sodium Butyrate (NaB). We treated them with each drug for 120 hours. Flow cytometry analysis, immunofluorescence staining for E-cadherin and senescence associated beta-galactosidase assays and immunoblotting for senescence related proteins assessed NSCLC cell outgrowth and morphology. Results: Both cell lines with 5-aza-dC or NaB treatment changed morphology and increased size but decreased cell numbers. 5-aza-CR causes apoptosis in both cell lines. In A549, E-cadherin expression increased after 5-aza-dC treatment. There is no E-cadherin expression in H1299 with or without treatment. Both cell lines with 5-aza-dC were positive for Senescence-associated beta-galactosidase staining, H3K9me3 and gamma-H2AX. Conclusion: Taking together these findings strongly suggest the ability of 5-aza-dC to induce cellular senescence in NSCLC cells. The cellular senescence induced by a 5-aza-dC approach has to be considered a therapeutic option for NSCLC and an important phenomenon to further investigate in the next future. Citation Format: Masashi Furukawa, Yuka Mimura, Hiroyuki Tao, Yusuke Mimura, Kazunori Okabe. 5-aza-2’-Deoxycytidine induces cellular senescence in non-small cell lung cancer. [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 2842.