Analysis of the combined action of miR-143 and miR-145 on oncogenic pathways in colorectal cancer cells reveals a coordinate program of gene repression

Abstract

MicroRNAs (miRNAs) from the gene cluster miR-143-145 are diminished in cells of colorectal tumor origin when compared with normal colon epithelia. Until now, no report has addressed the coordinate action of these miRNAs in colorectal cancer (CRC). In this study, we performed a comprehensive molecular and functional analysis of the miRNA cluster regulatory network. First, we evaluated proliferation, migration, anchorage-independent growth and chemoresistance in the colon tumor cell lines after miR-143 and miR-145 restoration. Then, we assessed the contribution of single genes targeted by miR-143 and miR-145 by reinforcing their expression and checking functional recovery. Restoring miR-143 and miR-145 in colon cancer cells decreases proliferation, migration and chemoresistance. We identified cluster of differentiation 44 (CD44), Kruppel-like factor 5 (KLF5), Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) and v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) as proteins targeted by miR-143 and miR-145. Their re-expression can partially revert a decrease in transformation properties caused by the overexpression of miR-143 and miR-145. In addition, we determined a set of mRNAs that are diminished after reinforcing miR-143 and miR-145 expression. The whole transcriptome analysis ascertained that downregulated transcripts are enriched in predicted target genes in a statistically significant manner. A number of additional genes, whose expression decreases as a direct or indirect consequence of miR-143 and miR-145, reveals a complex regulatory network that affects cell signaling pathways involved in transformation. In conclusion, we identified a coordinated program of gene repression by miR-143 and miR-145, in CRC, where either of the two miRNAs share a target transcript, or where the target transcripts share a common signaling pathway. Major mediators of the oncosuppression by miR-143 and miR-145 are genes belonging to the growth factor receptor-mitogen-activated protein kinase network and to the p53 signaling pathway.

Colorectal cancer carcinogenesis: a review of mechanisms

“…Their downregulation is an early event and occurs even before the APC gene aberrations 144 . The two miRNAs function as oncosuppressors in a coordinated fashion, that is, they either target the same genes or different genes regulating the same pathway 145 .…”

TAZ is required for metastatic activity and chemoresistance of breast cancer stem cells

“…35 Briefly, 100 ng of total RNA was labeled and hybridized to the Affymetrix GeneChip1.0ST array (Affymetrix, Santa Clara, CA, USA) following the manufacturer's instructions. Data analyses were performed by comparing tool classes of BRB-ArrayTools.…”

MicroRNA-202-3p Inhibits Cell Proliferation by Targeting ADP-Ribosylation Factor-like 5A in Human Colorectal Carcinoma

“…Over the past decade, the contribution of miRNAs (11), such as let-7 (12, 13), miR-17 (14,15), miR-21 (16)(17)(18)(19), miR-31 (20,21), miR-95 (22), miR-101 (23,24), miR-135 (25,26), miR-137 (27), miR-139 (28,29), miR-143 (30)(31)(32), miR-145 (31,33), miR-155 (34), miR-183 (35), and miR-195 (36), to colorectal carcinogenesis has been examined. In a previous study, we determined that miR-95 is frequently overexpressed in colorectal cancer and acts as an important inducer of proliferation via the negative regulation of SNX1 expression (22).…”