He et al. Journal of Experimental & Clinical Cancer Research 2011, 30:109 http://www.jeccr.com/content/30/1/109 Page 9 of 9 future studies are needed to evaluate the potential power of specific CDK8 inhibitors candidate on the downregulation of b-catenin expression, and subse- quently on the inhibition of proto-oncogenes. Our observations demonstrated that the activity of CDK8 is essential to be able to regulate b-catenin-dependent transcription and transformation in colon cancer cells. Accordingly, it is indicated that the intervene stategy targeting CDK8 in colon cancer may be of clinical value. Conclusions In this study, we demonstrated that CDK8 specific siRNA transfection down-regulated the expression of CDK8, which is expressed in a high fraction in colon cancer. We also found out that CDK8 specific siRNA inhibited the proliferation of colon cancer cells, pro- moted their apoptosis and arrested these cells in the G0/G1 phase. In addition, CDK8 inhibition may be associated with the down-regulation of b-catenin. Our results showed that CDK8 and b-catenin could be pro- mising target in the regulation of colon cancer by the control of b-catenin through CDK8. Acknowledgements This work was supported by natural science research grants in University of Jiangsu Province, China (No.09KJD320005), grants from Medical Science and Technology Development Foundation, Jiangsu Province Department of Health, China (No.H201013), Program for Postgraduate Research Innovation in University of Jiangsu Province, China (No.CX10B_054Z), and Project of Youth Foundation in Science and Education of Department of Public Health of Suzhou, China (No.SWKQ1004). Author details 1Department of General Surgery, the First Affiliated Hospital of Soochow University, 215006 Suzhou, Jiangsu Province, China. 2Department of immunology, Soochow University, 215006 Suzhou, Jiangsu Province, China. Authors’ contributions SH, YY, and LW carried out literature research, experimental studies and data acquisition, participated in the study design, and drafted the manuscript. MY and YZ participated in the design of the study and performed the statistical analyses. XZ proposed the study, and participated in its design and coordination and helped to draft, and assisted writing the manuscript. All authors read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Received: 30 August 2011 Accepted: 22 November 2011 Published: 22 November 2011 References 1. Walther A, Johnstone E, Swanton C, Midgley R, Tomlinson I, Kerr D: Genetic prognostic and predictive markers in colorectal cancer. Nat Rev Cancer 2009, 9(7):489-99. 2. Bienz M, Clevers H: Linking colorectal cancer to Wnt signaling. Cell 2000, 103:311-320. 3. Firestein R, Hahn WC: Revving the Throttle on an oncogene: CDK8 takes the driver seat. Cancer Res 2009, 69:7899-7901. 4. 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Journal of Experimental & Clinical Cancer Research 2011 30:109.