An epigenetic role for PRL-3 as a regulator of H3K9 methylation in colorectal cancer
- Yongxia Liu1,2,
- Ping Zheng1,2,
- Yuhong Liu3,
- Tianhai Ji4,
- Xunhua Liu1,2,
- Su Yao1,2,
- Xing Cheng1,2,
- Ying Li1,2,
- Lin Chen1,2,
- Zhengquan Xiao1,2,
- Jun Zhou2,
- Jianming Li1,2
- 1Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, People's Republic of China
- 2Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, People's Republic of China
- 3Department of Pathology, Baoan Hospital, Southern Medical University, ShenZhen, People's Republic of China
- 4Department of Pathology, the 174th Hospital of PLA, Xiamen, People's Republic of China
- Correspondence to Professor Jianming Li Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, People's Republic of China;
Contributors The first five authors contributed equally to this paper. YXL, PZ, YHL and THJ: study design, acquisition of data, analysis and interpretation of data, drafting of the manuscript; XHL, SY, CX, YL, LC and ZQX: acquisition of data, technical support; JZ: material support; JML: study concept and design, drafting and critical revision of the manuscript for important intellectual content and obtaining funding.
- Received 12 August 2011
- Accepted 20 January 2012
- Published Online First 16 February 2012
Objective This study investigated the epigenetic role of PRL-3, a key metastasis gene in colorectal cancer (CRC), as a regulator of histone demethylation and the functions of Jumonji domain-containing protein 1B (JMJD1B) and JMJD2B in the progression of CRC.
Methods PRL-3-associated proteins were analysed using functional distribution and category enrichment analysis. Western blotting and immunofluorescence were used to detect nuclear PRL-3. The relationship between PRL-3 and JMJD1B or JMJD2B and the roles of JMJD1B, JMJD2B and PRL-3 in histone demethylation were determined after these proteins were knocked down using RNA interference. Case–control studies on JMJD1B and JMJD2B in patients with CRC were performed using immunohistochemical analysis. The in vitro functional effects of JMJD2B and JMJD1B were examined further.
Results JMJD1B and JMJD2B, two histone demethylases, were enriched among PRL-3-associated proteins. Nuclear PRL-3 was observed in CRC cells and clinical samples of CRC. The expression of nuclear PRL-3 was increased in patients with CRC at more advanced Dukes' stages. PRL-3 was involved in the regulation of histone methylation by affecting the activities of JMJD1B and JMJD2B. A low expression of the JMJD1B protein was positively correlated with the lymph node status (p=0.032), Dukes' classification (p=0.008) and TNM staging (p=0.022) of patients with CRC. A high expression of JMJD2B was positively correlated with the lymph node status (p=0.03), Dukes' classification (p=0.036) and tumour invasion (p=0.003) of patients with CRC. A loss-of-function analysis confirmed that JMJD2B promoted the proliferation, colony formation and migration of human CRC cells.
Conclusion Our data reveal a new role for PRL-3 as a key regulator of histone demethylation. JMJD1B seems to be a candidate tumour suppressor and JMJD2B seems to be a potential oncoprotein in the development and progression of CRC.
- histone demethylation
- colorectal cancer
- cell migration
- pathobiology of biliary epithelia
- stem cells
- molecular biology
- molecular carcinogenesis
Funding This work was supported by the National Natural Science Foundation of China (Grants 81090422, 81001110 and 30971361) and the Program for New Century Excellent Talents in University of China (NCET-10-0092).
Correction notice This paper has been modified since it was first published online. The author affiliations have been corrected.
Competing interests None.
Patient consent Obtained.
Ethics approval This study was conducted with the approval of the ethics committee of Southern Medical University. Tissue sample of colorectal cancer removed from the patients.
Provenance and peer review Not commissioned; externally peer reviewed.