EZH2 Silencing with RNA Interference Induces G₂/M Arrest in Human Lung Cancer CellsIn Vitro

Abstract

Nonsmall-cell lung cancer has a high mortality rate and poor prognosis. In the present study, we silenced EZH2 and explored the consequent cell cycle changes. The expression of cell-cycle-related proteins, including p53, p21, Cdc2, and cyclin B1, was detected with western blotting, and the cell cycle distribution was determined with flow cytometry. Inhibition of EZH2 expression changed the cell cycle distribution, in particular inducing G2/M arrest. Expression of Cdc2 and cyclin B1 was significantly decreased in A549 and HTB-56 cells after EZH2-siRNA treatment. In addition, p53 expression was increased by 21% and 18%, and p21 expression was increased by 31% and 23%, in A549 and HTB-56 cells, respectively, in the presence of EZH2-siRNA. This study clearly demonstrates that modulation of EZH2 expression with siRNA affects the cell cycle and the expression levels of p53 and p21, thereby changing cyclin B1 and Cdc2 expression and inducing G2/M arrest. These results may explain the observed antitumor activity of EZH2 silencing. Such explorations of the molecular mechanism of EZH2 will help us develop novel approaches to the diagnosis, treatment, and prevention of nonsmall-cell lung cancer.

EZH2 promotes tumor progression via regulating VEGF-A/AKT signaling in non-small cell lung cancer

“…The results have shown that overexpressing EZH2 increased VEGF-A expression, promoted cell proliferation and cell cycle progression, migration and invasion of lung cancer cells, while silencing EZH2 had the opposite effects. Prior studies have shown that EZH2 promotes cell cycle progression by upregulating cell division cycle 2 (Cdc2) and cyclin B1 through the p53 pathway in lung cancer [6]. Repression of EZH2 induced cell cycle arrest and inhibited tumor growth of glioblastoma [25].…”

“…Recent studies have shown that EZH2 overexpression predicts poor patient prognosis and is a frequent event in various cancers, such as breast cancer [1], malignant prostate cancer [2], and hepatocellular carcinoma [3]. There are reports depicting the expression and oncogenic role of EZH2 in lung tumorigenesis [4,5] and EZH2 has been suggested to modulate several pathophysiological processes by promoting cell proliferation and cell cycle progression [6], accelerating cell infiltration and metastasis [7], and inhibiting apoptosis [8]. EZH2 also activates tumor angiogenesis by silencing vasohibin 1 in ovarian cancer [9].…”

miR‐101 Acts as a Tumor Suppressor by Targeting Kruppel‐like Factor 6 in Glioblastoma Stem Cells

“…The smallest tumors produced by the combination of overexpressed miR‐101 and inhibited KLF‐6 suggested that other factors or signal pathways might be involved in this inhibitory effect, exhibiting a synergistic inhibitory effect of miR‐101 overexpression and KLF6 inhibition. Previous studies showed that overexpression of miR‐101 downregulated enhancer of zeste homolog 2 which could upregulate p53 expression in human lung cancer , and KLF6 silencing upregulated p53 expression in hepatocellular carcinoma cell lines . Moreover, overexpressed miR‐101 could inhibit the activation of Wnt pathway and the expression of c‐myc which were upregulated by KLF6 inhibition .…”

Down-Regulation of TSLP After EZH2 Silencing in ESCC Cell Line

“…The more important point is that EZH 2 is concerned more with stem cell characteristics especial cancerous stem cell characteristics and the function of cell at the beginning of becoming cancerous (6). EZH 2 is expressed broadly in embryo's development and its expression decreases through differentiation and maturity (4).…”