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Journal of Biomedicine and Biotechnology
Volume 2010 (2010), Article ID 737535, 10 pages
Research Article

Depletion of DNMT3A Suppressed Cell Proliferation and Restored PTEN in Hepatocellular Carcinoma Cell

1Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, Southeast University, Nanjing 210009, China
2Institute of Life Science, Southeast University, Nanjing 210009, China
3Prenatal Diagnosis Center, Nanjing Maternity and Child Health Care Hospital, Nanjing 210009, China

Received 24 November 2009; Revised 25 February 2010; Accepted 26 February 2010

Academic Editor: Mouldy Sioud

Copyright © 2010 Zhujiang Zhao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Promoter hypermethylation mediated by DNA methyltransferases (DNMTs) is the main reason for epigenetic inactivation of tumor suppressor genes (TSGs). Previous studies showed that DNMT1 and DNMT3B play an important role in CpG island methylation in tumorigenesis. Little is known about the role of DNMT3A in this process, especially in hepatocellular carcinoma (HCC). In the present study, increased DNMT3A expression in 3 out of 6 HCC cell lines and 16/25 (64%) HCC tissues implied that DNMT3A is involved in hepatocellular carcinogenesis. Depletion of DNMT3A in HCC cell line SMMC-7721 inhibited cell proliferation and decreased the colony formation (about 65%). Microarray data revealed that 153 genes were upregulated in DNMT3A knockdown cells and that almost 71% (109/153) of them contain CpG islands in their region. 13 of them including PTEN, a crucial tumor suppressor gene in HCC, are genes involved in cell cycle and cell proliferation. Demethylation of PTEN promoter was observed in DNMT3A-depleted cells implying that DNMT3A silenced PTEN via DNA methylation. These results provide insights into the mechanisms of DNMT3A to regulate TSGs by an epigenetic approach in HCC.