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Open Access Highly Accessed Research article

Pluripotency-associated genes in human nasopharyngeal carcinoma CNE-2 cells are reactivated by a unique epigenetic sub-microenvironment

Jun-Xia Cao12*, Yu-Xin Cui3, Zi-Jie Long4, Zhong-Min Dai5, Ji-Yan Lin6, Yi Liang1, Fei-Meng Zheng1, Yi-Xin Zeng1 and Quentin Liu14*

Author Affiliations

1 State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-sen University, 650 Dongfeng Road, Guangzhou 510060, PR China

2 The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine 04609, USA

3 Department of Pathology, University of Cambridge, Hills Road, Cambridge BS2 0QQ, UK

4 Department of Hematology, Third Affiliated Hospital, Sun Yat-sen University, 600 Tianhe Road, Guangzhou 510630, PR China

5 College of Life Sciences, Zhejiang University, 388 Yuhangtang Road, Hangzhou 310058, PR China

6 Department of Emergency, First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan 2nd Road, Guangzhou 510060, PR China

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BMC Cancer 2010, 10:68  doi:10.1186/1471-2407-10-68

Published: 25 February 2010

Abstract

Background

There is increasing evidence that cancers contain their own stem-like cells, and particular attention has been paid to one subset of cancer-stem cells termed side population (SP). Stem cells under normal physical conditions are tightly controlled by their microenvironment, however, the regulatory role of the microenvironment surrounding cancer stem cells is not well characterized yet. In this study we found that the phenotype of SP can be "generated" by macrophage-like cells under conditioned culture. Furthermore the gene regulation pathway involved in cellular reprogramming process was investigated.

Methods

The selection and identification of SP in 50 CNE-2 single cell clones were performed by flow cytometry. The transwell assay and immunofluorescence staining were used to measure migration and cancer stem cell characters of non-SP single clone cells cultured with conditioned medium respectively. The subtraction suppression hybridization (SSH) technique and northern blotting analysis was applied to explore the pluripotency-associated genes under a unique epigenetic sub-microenvironment.

Results

Among 50 clones, only one did not possess SP subpopulation while others did. The non-SP cells induced by macrophage-like cells showed more aggressive characters, which increased cell migration compared with the control cells and showed some fraction of SP phenotype. These cells expressed distinguished level of pluripotency-associated genes such as ADP-ribosylation factor-like 6 interacting protein (ARMER), poly (rC) binding protein 1 (PCBP1) and pyruvate dehydrogenase E1-β subunit (PDHB) when subjected to the environment.

Conclusion

To our knowledge, this is the first study to demonstrate that non-SP single-clone cells can be induced to generate a SP phenotype when they are cultured with conditioned medium of macrophage-like cells, which is associated with the reactivation of pluripotency-associated genes.