Knockdown of FoxM1 by siRNA interference decreases cell proliferation, induces cell cycle arrest and inhibits cell invasion in MHCC-97H cells in vitro

Qi-Fei Wu,Chang Liu,Yi Lü,Dong Liu,Ming-Hui Tai,Min Tian,Rui-Tao Wang,Lei Lei

doi:10.1038/aps.2010.4

Abstract

To investigate the effects of small interfering RNA (siRNA) knockdown of forkhead box M1 (FoxM1) on the proliferation and invasion capacities of human hepatocellular carcinoma MHCC-97H cells in vitro. The expression levels of FoxM1 in human hepatocellular carcinoma samples, adjacent non-hepatocellular carcinoma liver samples and MHCC-97 cell lines were detected by RT-PCR and Western blotting. FoxM1 siRNA was transfected into MHCC-97H cells with Lipofectamine 2000. Cell growth was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and cell cycle analysis was performed by flow cytometry. Protein expression levels were evaluated by Western blotting. Anchorage-independent growth and the invasive potency of MHCC-97H cells were measured by soft agar colony formation and a transwell cell invasion assay, respectively. FoxM1 was over-expressed in hepatocellular carcinoma samples compared to adjacent non-hepatocellular carcinoma liver samples. FoxM1 siRNA was successfully transfected into MHCC-97H cells, resulting in the significant inhibition of FoxM1 mRNA and protein expression. Down-regulation of FoxM1 inhibited cell proliferation, caused cell cycle arrest, and decreased invasion of MHCC-97H cells. Compared with control and mock groups, the FoxM1 siRNA transfected cells showed decreased protein expressions of cyclin B1 and cyclin D1, whereas p27 protein expression was increased. Down-regulation of FoxM1 reduced the expression of matrix metalloproteinase-2 (MMP-2) and urokinase plasminogen activator (uPA). FoxM1 is functionally involved in hepatocellular carcinoma cell proliferation and invasion and is a potential target for hepatocellular carcinoma therapy.

Highlights

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the third most common cause of cancer mortality, causing about 500 000 deaths per annum
Expression of Forkhead box M1 (FoxM1) in HCC and adjacent non-HCC liver samples Using Reverse transcription polymerase chain reaction (RT-PCR), FoxM1 mRNA was found to be significantly overexpressed in 87.5% of HCC specimens, whereas it was detected in only 12.5% of adjacent non-HCC liver samples (P
The results showed that FoxM1 protein expression could be detected in 93.75% of HCC samples but only 12.5% of adjacent non-HCC liver samples (P

Summary

Introduction

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the third most common cause of cancer mortality, causing about 500 000 deaths per annum. Most HCC cases occur in either Eastern Asia, especially in China, or sub-Saharan Africa[1]. The prognosis for HCC is still poor, as no effective therapy has been developed[2]. Gene targeting is a relatively new approach to cancer therapy, and a key requirement of gene targeting therapy is to have specific and efficient targets. Discovery of a new specific and efficient molecular target for HCC could be essential for reducing the mortality of this devastating malignancy. Forkhead box M1 (FoxM1) belongs to the forkhead box

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