Identification of CD24 as a cancer stem cell marker in human nasopharyngeal carcinoma
Authors: Yu-Sun Chang
Tsung-Teng Huang
Chih-Jung Chang
K P Shravan Kumar
Chun-Hung Yang
David M Ojcius
Chia-Chen Lu
Hung-Chi Lin
Jan Martel
Hui-Ling Wang
John D Young
Hsin-Chih Lai
Yi-Sheng Lin
Journal: PLoS ONE (2014)
Discipline: Multidisciplinary
Keywords: Cancer stem cells; CSC biomarkers; nasopharyngeal carcinoma; CD24+ cells; stem cell genes
Affiliations: Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan, Republic of China; Division of Applied Toxicology, Taiwan Agricultural Chemicals and Toxic Substances Research Institute, Council of Agriculture, Executive Yuan, Taichung, Taiwan, Republic of China., Department of Medical Biotechnology and Laboratory Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan, Republic of China; Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan, Republic of China., Department of Medical Biotechnology and Laboratory Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan, Republic of China; Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan, Republic of China; Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan, Republic of China., Department of Respiratory Therapy, Fu Jen Catholic University, Taipei, Taiwan, Republic of China., Department of Medical Biotechnology and Laboratory Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan, Republic of China; Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan, Republic of China; Center for Molecular and Clinical Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan, Republic of China; Research Center of Bacterial Pathogenesis, College of Medicine, Chang Gung University, Taoyuan, Taiwan, Republic of China., Center for Molecular and Clinical Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan, Republic of China., Center for Molecular and Clinical Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan, Republic of China; Department of Molecular Cell Biology and Health Sciences Research Institute, University of California Merced, Merced, California, United States of America., Molecular Medicine Research Center, College of Medicine, Chang Gung University, Taoyuan, Taiwan, Republic of China., Center for Molecular and Clinical Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan, Republic of China; Laboratory of Cellular Physiology and Immunology, Rockefeller University, New York, New York, United States of America; Biochemical Engineering Research Center, Ming Chi University of Technology, Taipei, Taiwan, Republic of China.

Abstract:  Cancer stem cells (CSCs) represent a unique sub-population of tumor cells with the ability to initiate tumor growth and sustain self-renewal. Although CSC biomarkers have been described for various tumors, only a few markers have been identified for nasopharyngeal carcinoma (NPC). In this study, we show that CD24+ cells isolated from human NPC cell lines express stem cell genes (Sox2, Oct4, Nanog, Bmi-1, and Rex-1), and show activation of the Wnt/β-catenin signaling pathway. CD24+ cells possess typical CSC characteristics that include enhanced cell proliferation, increased colony and sphere formation, maintenance of cell differentiation potential in prolonged culture, and enhanced resistance to chemotherapeutic drugs. Notably, CD24+ cells produce tumors following inoculation of as few as 500 cells in immunodeficient NOD/SCID mice. CD24+ cells further show increased invasion ability in vitro, which correlates with enhanced expression of matrix metalloproteinase 2 and 9. In summary, our results suggest that CD24 represents a novel CSC biomarker in NPC. 

Retracted: No

PubPeer comments:
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 January 2019 Expression of Concern found here: https: journals.plos.org plosone article?id=10.1371 journal.pone.0210304 Other than the duplications noticed above for Figures 7B and 7C, the EoC mentions an additional duplication between Figure 2B and 8B. Here is an illustration of that duplication, marked with orange boxes: ![file] From the EoC:  *We regret that the journal did not correct Figs 2B and 7B sooner. While the authors stand by the validity of the experimental data and the conclusions reached in the study, they were unable to provide all of the original images for the mouse experiments, as described above. In light of the image duplications and the unavailability of primary data, the PLOS ONE Editors have concerns about the strength of evidence supporting the in vivo claims made in the article and, therefore, issue this Expression of Concern.* , 
 We are grateful for this comment. The unintended error mentioned was actually identified by ourself. We repeated the experiment, and the amount of Lamin B1 in the nuclear fraction that acted as the basal level control was shown in the EoC. Results obtained showed a similar amount of Lamin B1 was added as a loading control. ,