BACKGROUND: Drug resistance in colorectal cancers is assumed to be mediated by changes in the expression of microRNAs, but the specific identities and roles of microRNAs are largely unclear. We examined the effect of 5-fluorouracil (5-FU) resistance on microRNA expression. METHODS: Two types of 5-FU-resistant colon cancer cells were derived from the DLD-1 and KM12C cell lines. The expressions of microRNAs were profiled with a microarray containing 723 microRNAs and validated by quantitative real-time polymerase chain reaction (qRT-PCR). To survey the downstream mediators of microRNA, we used a microRNA:mRNA immunoprecipitation (RIP)-Chip and pathway analysis tool to identify potential direct targets of microRNA. RESULTS: In response to 5-FU, miR-19b and miR-21 were over-expressed in 5-FU-resistant cells. Of note, miR-19b was up-regulated 3.47-fold in the DLD-1 resistant cells, which exhibited no alteration in cell cycle profiles despite exposure to 5-FU. After transfection of miR-19b, specific mRNAs were recruited to microRNA:mRNA complexes isolated with Ago2 antibody and subjected to whole-genome transcriptional analysis. In this analysis, 66 target mRNAs were enriched by at least 5.0-fold in the microRNA:mRNA complexes from DLD-1 resistant cells. Ingenuity pathway analysis of mRNA targets significantly (P < 0.05) indicated the category "Cell Cycle" as a probable area of the molecular and cellular function related with 5-FU resistance. Among candidate mRNA targets, SFPQ and MYBL2 have been linked to cell cycle functions. CONCLUSIONS: We revealed up-regulation of miR-19b in response to 5-FU and potential targets of miR-19b mediating the cell cycle under treatment with 5-FU. Our study provides an important insight into the mechanism of 5-FU resistance in colorectal cancers.
BACKGROUND: Drug resistance in colorectal cancers is assumed to be mediated by changes in the expression of microRNAs, but the specific identities and roles of microRNAs are largely unclear. We examined the effect of 5-fluorouracil (5-FU) resistance on microRNA expression. METHODS: Two types of 5-FU-resistant colon cancer cells were derived from the DLD-1 and KM12C cell lines. The expressions of microRNAs were profiled with a microarray containing 723 microRNAs and validated by quantitative real-time polymerase chain reaction (qRT-PCR). To survey the downstream mediators of microRNA, we used a microRNA:mRNA immunoprecipitation (RIP)-Chip and pathway analysis tool to identify potential direct targets of microRNA. RESULTS: In response to 5-FU, miR-19b and miR-21 were over-expressed in 5-FU-resistant cells. Of note, miR-19b was up-regulated 3.47-fold in the DLD-1 resistant cells, which exhibited no alteration in cell cycle profiles despite exposure to 5-FU. After transfection of miR-19b, specific mRNAs were recruited to microRNA:mRNA complexes isolated with Ago2 antibody and subjected to whole-genome transcriptional analysis. In this analysis, 66 target mRNAs were enriched by at least 5.0-fold in the microRNA:mRNA complexes from DLD-1 resistant cells. Ingenuity pathway analysis of mRNA targets significantly (P < 0.05) indicated the category "Cell Cycle" as a probable area of the molecular and cellular function related with 5-FU resistance. Among candidate mRNA targets, SFPQ and MYBL2 have been linked to cell cycle functions. CONCLUSIONS: We revealed up-regulation of miR-19b in response to 5-FU and potential targets of miR-19b mediating the cell cycle under treatment with 5-FU. Our study provides an important insight into the mechanism of 5-FU resistance in colorectal cancers.
Authors: Elisa Giovannetti; Niccola Funel; Godefridus J Peters; Marco Del Chiaro; Leyla A Erozenci; Enrico Vasile; Leticia G Leon; Luca E Pollina; Annemieke Groen; Alfredo Falcone; Romano Danesi; Daniela Campani; Henk M Verheul; Ugo Boggi Journal: Cancer Res Date: 2010-05-11 Impact factor: 12.701
Authors: Aaron J Schetter; Suet Yi Leung; Jane J Sohn; Krista A Zanetti; Elise D Bowman; Nozomu Yanaihara; Siu Tsan Yuen; Tsun Leung Chan; Dora L W Kwong; Gordon K H Au; Chang-Gong Liu; George A Calin; Carlo M Croce; Curtis C Harris Journal: JAMA Date: 2008-01-30 Impact factor: 56.272
Authors: Paul E Blower; Ji-Hyun Chung; Joseph S Verducci; Shili Lin; Jong-Kook Park; Zunyan Dai; Chang-Gong Liu; Thomas D Schmittgen; William C Reinhold; Carlo M Croce; John N Weinstein; Wolfgang Sadee Journal: Mol Cancer Ther Date: 2008-01-09 Impact factor: 6.261
Authors: Liang Huang; Jin Lin Cai; Pin Zhu Huang; Liang Kang; Mei Jin Huang; Lei Wang; Jian Ping Wang Journal: Am J Cancer Res Date: 2017-10-01 Impact factor: 6.166