Yuan et al. BMC Cancer 2011, 11:57 http://www.biomedcentral.com/1471-2407/11/57 mediated cell proliferation in some normal and tumor cells [14,18]. However, whether miR-203 regulates the expression of ΔNp63 in ESCC has not been identified before. Here, we showed that miR-203 could signifi- cantly inhibit ΔNp63 protein expression without chan- ging the expression level of ΔNp63 mRNA, suggesting that miR203 negatively regulated the expression of ΔNp63 at the posttranscriptional level in ESCC. More- over, we demonstrated that re-expressing ΔNp63 in miR-203 transfected ESCC cells could significantly attenuate miR-203 induced inhibition of cell prolifera- tion. Taken together, our results suggest that miR-203 may function as a tumor suppressor by regulating ΔNp63-mediated signal pathways in human ESCC. However, we noticed that the proliferative capacity of the ESCC cells cotransfected with miR-203 and pcDNA- ΔNp63 plasmid, though much higher than that of the cells cotransfected with miR-203 and empty pcDNA plasmid, is still significantly lower than that of the cells cotransfected with control microRNA and empty pcDNA plasmid (Additional file 1, Figure S3). This result, combined with the fact that the expression level of ΔNp63 protein in the cells cotransfected with miR- 203 and pcDNA-ΔNp63 was significantly higher than that in cells cotransfected with control microRNA and empty pcDNA plasmid (Additional file 1, Figure S4), suggest that miR-203 might regulate the proliferation of ESCC cells through multiple target genes. In this respect, the underlying mechanisms of miR-203 in regu- lating the proliferation of ESCC cell warrant further investigation. Conclusions In summary, we have demonstrated that miR-203 and ΔNp63 play an important role in ESCC cell proliferation regulation. MiR-203 can significantly inhibit the prolif- eration of ESCC cell through the ΔNp63-mediated sig- nal pathway. Based on these findings, we propose that miR-203 might be used as a therapeutic agent for ESCC. Additional material Additional file 1: Results of the expression of miR-203, p63 isoforms (ΔNp63 and TAp63) in Eca109 and TE-1 cell lines; the proliferative capacity of cells cotransfected with miR-203 and pcDNA-ΔNp63 plasmid (or with control microRNA and empty pcDNA plasmid); the expression level of ΔNp63 protein in cells cotransfected with miR- 203 and pcDNA-ΔNp63 plasmid (or with control microRNA and empty pcDNA plasmid); cell cycle analysis of Eca109 and TE-1 cell transfected with miR-203 and ΔNp63 siRNA. Acknowledgements This work was supported by the National Natural Science Foundation of China (grant 30872552) and the Shanghai Municipal Natural Science Foundation (grant 8140902201 and 10140902300). Page 9 of 10 Author details 1Institute of Cardiothoracic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, PR China. 2Department of Cardiothoracic Surgery, Fuzhou General Hospital of Nanjing Command, PLA. Fujian, PR China. 3Department of Cardiothoracic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, PR China. Authors’ contributions SDH conceived the design of the study and was in charge of its coordination. YY participated in data analysis, performed data interpretation and drafted the manuscript. ZYZ carried out the cell proliferation analysis and helped to draft the manuscript. XHL performed molecular biology experiment and helped to draft the manuscript. DJG participated in cell culture and Luciferase reporter assay. JT participated in flow cytometry analysis. HZC co-conceived the design of the study. All authors read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Received: 1 November 2010 Accepted: 7 February 2011 Published: 7 February 2011 References 1. Enzinger PC, Mayer RJ: Esophageal cancer. N Engl J Med 2003, 349:2241-2252. 2. Li JY: Epidemiology of esophageal cancer in China. Natl Cancer Inst Monogr 1982, 62:113-120. 3. Gamliel Z, Krasna MJ: Multimodality treatment of esophageal cancer. Surg Clin North Am 2005, 85:621-630. 4. Pfaffl MW: A new mathematical model for relative quantification in real- time RT-PCR. Nucleic Acids Res 2001, 29:e45. 5. Gratas C, Tohma Y, Barnas C, Taniere P, Hainaut P, Ohgaki H: Up-regulation of Fas (APO-1/CD95) ligand and down-regulation of Fas expression in human esophageal cancer. Cancer Res 1998, 58:2057-2062. 6. Mizushima T, Nakagawa H, Kamberov YG, Wilder EL, Klein PS, Rustgi AK: Wnt-1 but not epidermal growth factor induces beta-catenin/T-cell factor-dependent transcription in esophageal cancer cells. Cancer Res 2002, 62:277-282. 7. Yang L, Leung AC, Ko JM, Lo PH, Tang JC, Srivastava G, Oshimura M, Stanbridge EJ, Daigo Y, Nakamura Y, Tang CM, Lau KW, Law S, Lung ML: Tumor suppressive role of a 2.4 Mb 9q33-q34 critical region and DEC1 in esophageal squamous cell carcinoma. Oncogene 2005, 24:697-705. 8. Ambros V: microRNAs: tiny regulators with great potential. Cell 2001, 107:823-826. 9. Esquela-Kerscher A, Slack FJ: Oncomirs - microRNAs with a role in cancer. Nat Rev Cancer 2006, 6:259-269. 10. Hobert O: Gene regulation by transcription factors and microRNAs. Science 2008, 319:1785-1786. 11. Chen CZ, Li L, Lodish HF, Bartel DP: MicroRNAs modulate hematopoietic lineage differentiation. Science 2004, 303:83-86. 12. Croce CM, Calin GA: miRNAs, cancer, and stem cell division. Cell 2005, 122:6-7. 13. Bueno MJ, Perez de Castro I, Gomez de Cedron M, Santos J, Calin GA, Cigudosa JC, Croce CM, Fernandez-Piqueras J, Malumbres M: Genetic and epigenetic silencing of microRNA-203 enhances ABL1 and BCR-ABL1 oncogene expression. Cancer Cell 2008, 13:496-506. 14. Lena AM, Shalom-Feuerstein R, Rivetti di Val Cervo P, Aberdam D, Knight RA, Melino G, Candi E: miR-203 represses ‘stemness’ by repressing DeltaNp63. Cell Death Differ 2008, 15:1187-1195. 15. Schetter AJ, Leung SY, Sohn JJ, Zanetti KA, Bowman ED, Yanaihara N, Yuen ST, Chan TL, Kwong DL, Au GK, Liu CG, Calin GA, Croce CM, Harris CC: MicroRNA expression profiles mediated with prognosis and therapeutic outcome in colon adenocarcinoma. JAMA 2008, 299:425-436. 16. Furuta M, Kozaki KI, Tanaka S, Arii S, Imoto I, Inazawa J: miR-124 and miR- 203 are epigenetically silenced tumor-suppressive microRNAs in hepatocellular carcinoma. Carcinogenesis 2010, 31:766-776. 17. Moll UM, Slade N: p63 and p73: roles in development and tumor formation. Mol Cancer Res 2004, 2:371-386. 18. Yi R, Poy MN, Stoffel M, Fuchs E: A skin microRNA promotes differentiation by repressing ‘stemness’. Nature 2008, 452:225-229.