Molecular mechanism of chemoresistance by miR-215 in osteosarcoma and colon cancer cells

Molecular Cancer

Research

Andrea Formentini¹  Marko Kornmann¹  Galina Botchkina²  Matthew A. Titmus³  Bo Song³  Jingfang Ju³  Yuan Wang⁴ 

[1] Department of General, Visceral and Transplantation Surgery, University of Ulm, 89075, Ulm, Germany;Department of Surgery, School of Medicine, Stony Brook University, Stony Brook, 11794, New York, USA;Translational Research Laboratory, Department of Pathology, School of Medicine, Stony Brook University, Stony Brook, 11794, New York, USA;Translational Research Laboratory, Department of Pathology, School of Medicine, Stony Brook University, Stony Brook, 11794, New York, USA;Basic Medical Sciences, Wuhan University, 430072, Wuhan, China;

关键词: Lock Nucleic Acid;    Western Immunoblot Analysis;    Tomudex;    Colon Cancer Stem Cell;    Stem Cell Quiescence;   

DOI  :  10.1186/1476-4598-9-96

 received in 2009-10-12, accepted in 2010-04-30,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundTranslational control mediated by non-coding microRNAs (miRNAs) plays a key role in the mechanism of cellular resistance to anti-cancer drug treatment. Dihydrofolate reductase (DHFR) and thymidylate synthase (TYMS, TS) are two of the most important targets for antifolate- and fluoropyrimidine-based chemotherapies in the past 50 years. In this study, we investigated the roles of miR-215 in the chemoresistance to DHFR inhibitor methotrexate (MTX) and TS inhibitor Tomudex (TDX).ResultsThe protein levels of both DHFR and TS were suppressed by miR-215 without the alteration of the target mRNA transcript levels. Interestingly, despite the down-regulation of DHFR and TS proteins, ectopic expression of miR-215 resulted in a decreased sensitivity to MTX and TDX. Paradoxically, gene-specific small-interfering RNAs (siRNAs) against DHFR or TS had the opposite effect, increasing sensitivity to MTX and TDX. Further studies revealed that over-expression of miR-215 inhibited cell proliferation and triggered cell cycle arrest at G2 phase, and that this effect was accompanied by a p53-dependent up-regulation of p21. The inhibitory effect on cell proliferation was more pronounced in cell lines containing wild-type p53, but was not seen in cells transfected with siRNAs against DHFR or TS. Moreover, denticleless protein homolog (DTL), a cell cycle-regulated nuclear and centrosome protein, was confirmed to be one of the critical targets of miR-215, and knock-down of DTL by siRNA resulted in enhanced G2-arrest, p53 and p21 induction, and reduced cell proliferation. Additionally, cells subjected to siRNA against DTL exhibited increased chemoresistance to MTX and TDX. Endogenous miR-215 was elevated about 3-fold in CD133+HI/CD44+HI colon cancer stem cells that exhibit slow proliferating rate and chemoresistance compared to control bulk CD133+/CD44+ colon cancer cells.ConclusionsTaken together, our results indicate that miR-215, through the suppression of DTL expression, induces a decreased cell proliferation by causing G2-arrest, thereby leading to an increase in chemoresistance to MTX and TDX. The findings of this study suggest that miR-215 may play a significant role in the mechanism of tumor chemoresistance and it may have a unique potential as a novel biomarker candidate.

【 授权许可】

Unknown   
© Song et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.