Abstract 1429: MYH8 R1292X: A novel mutation in relapsed AML induces EMT features and poor prognosis

Abstract

Abstract Introduction: Recent advances in tumor genomic analysis have led to the discovery of NPM1, FLT3, CEBPA, MLL, NRAS, and RUNX1 alterations as the cause of AML. Nevertheless, there is a limit to the treatment and clarification of AML, and research for the identification of novel genetic alterations that cause AML is actively underway. Materials and methods: In this study, we performed Whole exome sequencing (WES) with 53 AML patient's samples and conducted targeted re-sequencing using 391 AML patient's samples based on locus of somatic mutation that were found by WES. For functional validation of novel oncogenic mutations, we used CRISPR-Cas9 system to generate knock-in (KI) cell line. For characterization of mutant cells, we performed proliferation assay, cell cycle assay, adhesion assay, and wound healing assay. Epithelial to mesenchymal transition (EMT) markers were checked by western blotting. Results: Using WES and targeted resequencing, we could identify MYH8 R1292X novel mutation as recurrent potentially oncogenic mutation. Additional validation using separate AML cohort revealed MYH8 R1292X variants in four AML patients, suggesting that MYH8 R1292X is potential oncogenic mutation. In functional validation using KI cell line, we could not find change in morphology of KI cells. However, there was a difference in proliferation – the rate of proliferation was faster in KI cells than in cells without mutation. In the cell cycle assay, the mutant cells showed more S phase DNA than the non-mutant cells. Wound healing assay showed that the mutant cells had higher migration ability and lowered the ability of adhesion in comparison. PCR and western blot showed that EMT markers except vimentin increased in mutant cells.Survival analysis based on TCGA data showed that both the overall survival and the disease-free survival curves were significantly different according to MYH8 alterations. Conclusion: Taken together, we conclude that the novel alteration MYH8 R1292X is associated with recurrent AML and poor prognosis by increasing migration, and inducing an increase in EMT markers. Citation Format: Hyejoo Park, Daeyoon Kim, Dongchan Kim, Yungyeong Park, Youngil Koh, Sung-Soo Yoon. MYH8 R1292X: A novel mutation in relapsed AML induces EMT features and poor prognosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1429.