Downregulation of PHF19 inhibits cell growth and migration in gastric cancer

Objectives: The PHD Finger Protein 19 (PHF19), as a sub-component of polycomb repressive complex 2 (PRC2), has been identified to be associated with various biological processes. Aberrant expression of PHF19 has implicated in several cancer types. This study aims to investigate its function and clinical significance in gastric cancer for the first time.Methods: The expression of PHF19 was evaluated by quantitative real-time PCR (qRT-PCR) and immunohistochemistry. PHF19 was silenced by small interference RNAs and lentiviral particles in gastric cancer cells. Then cell growth was measured by CCK-8 assays, colony formation and in a mouse model. Transwell and wound healing assays were performed to detect cell migration. Western blot analysis was used to explore the downstream signaling factors in PHF19-silenced cells, xenograft tumors and gastric cancer samples.Results: PHF19 was frequently upregulated in gastric cancer tissues compared with adjacent normal stomach tissues and this upregulation was correlated with tumor cell differentiation and poor outcome of gastric cancer patients. Functionally, the silencing of PHF19 in gastric cancer cells led to decreased cell growth and migration. Stable knockdown of PHF19 inhibited the tumorigenicity of gastric cancer cells in nude mice model. Western blot results demonstrated that phosphorylated AKT and ERK were reduced upon PHF19 downregulation, implying the two signaling pathways possibly mediate the oncogenic roles of PHF19.Conclusions: We identified PHF19 as an oncogene candidate and provided a new potential drug target for gastric cancer.