Retinoblastoma Protein-Interacting Zinc Finger 1 (RIZ1) Regulates the Proliferation of Monocytic Leukemia Cells via Activation of p53

The role of retinoblastoma protein-interacting zinc finger 1 (RIZ1) on the cell growth of mouse and human monocytic leukemia cells was examined. RIZ1 expression was induced in response to tumor necrosis factor (TNF)-alpha. The expression was dependent on the nuclear factor-kappa B and AKT signaling. Further, RIZ1 expression led to the augmentation of p53 expression and the silencing of RIZ1 prevented it. On the other hand, a p53 inhibitor enhanced the TNF-alpha-induced RIZ1 expression. Silencing of RIZ1 augmented the proliferative activity of TNF-alpha-treated cells. Therefore, it is suggested that RIZ1 negatively regulated the cell proliferation of monocytic leukemia cells via activation of p53.