Abstract 4723: Innovative cancer treatment of human lung cancer cells PC-9 with a synthetic retinoid Am80 and EGCG via inhibition of HDAC4 and HDAC5

Abstract

Abstract A synthetic new retinoid Am80 (tamibarotene) is used for treatment of acute promyelocytic leukemia (APL) patients with resistance of all-trans-retinoic acid (ATRA). To potentiate efficacy of Am80, we challenged combination treatment of Am80 and EGCG on human lung cancer cell line PC-9. It is now well accepted that EGCG acts as synergist with numerous anticancer compounds, and that the average reduction of tumor volume for in vivo genograft mouse models implanted using various human cancer cell lines was 70.3% with combinations of 13 anticancer compounds and EGCG. We previously reported that combinations of NSAIDs (sulindac and celecoxib) or other retinoids (ATRA, 13-cis-RA and 9-cis-RA) and EGCG synergistically induced apoptosis of the cells along with strong expression of growth arrest and DNA-damage inducible gene 153 (GADD153) and death receptor (DR5) gene. Our objective was to investigate the mechanism of the synergistic induction for GADD153-DR5 apoptosis pathway. The proteomic analysis of lysine-acetylated proteins was conducted with a shotgun analysis using nanoLC-ESI-MS/MS in PC-9 cells. We found that the numbers of acetylated proteins were different: 551 acetylated proteins were found in non-treated cells, 331 proteins in cells treated with combination, and 59 proteins were common in both cases. Acetylation was mainly found in non-histone proteins, chaperons, transcription factors, and enzymes. The combination increased acetylated p53 (Lys382) about 3-fold compared with non-treated cells. In addition, combination significantly decreased the protein amounts of histone deacetylase (HDAC) 4 and HDAC 5 to 50% and 20%, respectively, but not HDAC6 among Class II HDACs. Class I HDACs (HDAC1, 2, and 3) were not decreased. All the results suggest that combination of Am80 and EGCG induces GADD153-DR5 apoptotic pathway, and reduces the amounts of HDAC4 and HDAC5 resulting in changing protein acetylation. Citation Format: Masami Suganuma, Yukiko Oya, Sonthaya Umsumarng, Keisuke Iida, Anchalee Rawangkhan, Ryo Sakai, Hiroyuki Kagechika, Koichi Shudo, Hirota Fujiki. Innovative cancer treatment of human lung cancer cells PC-9 with a synthetic retinoid Am80 and EGCG via inhibition of HDAC4 and HDAC5. [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 4723.