Epigenetic upregulation of MNAT1 by SMYD2 is linked to PI3K/AKT activation and tumorigenesis of pancreatic adenocarcinoma

Abstract

Dysregulation of histone methyltransferase SET and MYND domain-containing protein 2 (SMYD2) has been correlated with human developmental disorders and cancers. This research aims to investigate the roles of SMYD2 and its interacted molecules in pancreatic adenocarcinoma (PAAD). Two PAAD-related gene expression datasets were downloaded to screen key molecules involved in tumor progression. SMYD2 was expressed at high levels in PAAD tissues and cells. SMYD2 silencing suppressed while its overexpression promoted proliferation, invasiveness, migration, apoptosis resistance, and cell cycle progression of PAAD cells. Target molecules of SMYD2 were predicted by online tools and validated by chromatin immunoprecipitation and luciferase assays. SMYD2 catalyzed H3K36me2 modification at the promoter region of MNAT1 component of CDK activating kinase (MNAT1) to promote its transcription. MNAT1 was correlated with an unfavorable clinical outcome of PAAD patients. Alteration of MNAT1 alone also affected the malignant behavior of PAAD cells. Moreover, MNAT1 overexpression in cells rescued the malignant phenotype of cells suppressed by SMYD2 silencing. MNAT1 activated the phosphatidyl inositol 3-kinase/protein kinase B (PI3K/AKT) signaling. In vivo, SMYD2 silencing decreased the growth rate and weight of xenograft tumors in nude mice. Overall, this paper demonstrates that SMYD2-mediated MNAT1 upregulation is linked to PAAD tumorigenesis via PI3K/ AKT pathway activation.