In vitro functional studies indicated that miR-143 and miR-145 appear to function in opposing manners to either inhibit or augment cell proliferation in a metastatic CRC model.
The downregulation of miR-143 was further evaluated in colon cancer cell lines and in paired CRC and adjacent non-cancerous colonic tissues by qRT-PCR.
There was a higher expression of miR-21 and lower expression of miR-143 in CRC tissue in comparison with adjacent normal colon tissue (P < 0.0001; P < 0.0001, respectively).
MiR-20a and miR-31 were found to be significantly upregulated in more than one study, and miR-143 and miR-145 were found to be significantly downregulated in CRC tissue in six or more studies.
microRNAs (miRNAs) are small non-coding RNAs with important post-transcriptional regulatory functions. miRNA-21 (miR-21) is upregulated and miR-143 and miR-145 are downregulated in colorectal carcinoma.
We found that 67 miRNA precursors are upregulated in rectal cancer (p<0.05) and 21 of those have never been reported in colorectal cancer (CRC); 39 miRNA precursors are downregulated (p<0.05) and 24 novel dysregulated miRNAs were identified in rectal cancer. miR-31, miR-126 and miR-143 are differentially expressed between colon cancer and rectal cancer.
MicroRNA-143 expression was measured in CRC tissue and corresponding non-neoplastic colon tissue by RT-PCR and its expression level was correlated with clinico-pathological characteristics.
Taken together, these results revealed that miR-143 levels in human blood and tumor tissues are associated with CRC cancer occurrence, metastasis and drug resistance, and miR-143 levels may be used as a new diagnostic marker and therapeutic target for CRC in the future.
We found a global dysregulation of miRNAs, including an oncogenic miR-17-92 cluster and oncosuppressive miR-143-145 cluster, and snoRNAs in synchronous CRC.
In addition, the qRT-PCR validation demonstrated that 9 miRNAs were consistent dysregulated with the integrative analysis in CRC tissues, 4 miRNAs (miR-21-5p, miR-183-5p, miR-17-5p and miR-20a-5p) were up-regulated expression, and 5 miRNAs (miR-145-5p, miR-195-5p, miR-139-5p, miR-378a-5p and miR-143-3p) were down-regulated expression (all p < 0.05).
In order to evaluate if miR-143 and/or let-7b replenishment would re-sensitize CRC cells to paclitaxel treatment, we investigated in effect of miR-143 and let-7b replenishments on sensitivity to paclitaxel treatment in KRAS mutant LoVo and wild-type SW48 CRC cell lines.
According to our results, miR-21, a miRNA that is up-regulated in CRC, and miR-143, a miRNA that is down-regulated in CRC, are the two miRNAs that dominated the miRNA population in CR tissues, and probably are also the most important miRNAs in CRCs.
miR-143 was down-regulated in human CRC tissues, its expression negatively correlated with CRC metastasis. miR-143 negatively regulated ERBB3 expression by directly targeting its 3'UTR in human colorectal cancer cells.
Following overexpression of miR-143 in CRC cells, target gene matrix metalloproteinase 7 (MMP7) expression was detected by quantitative real-time PCR (qRT-PCR) and western blot.
Bioinformatics analysis, dual-luciferase reporter assays, and RNA immunoprecipitation assays showed that miR-143 can interact with UCC, and we found that UCC expression inversely correlates with miR-143 expression in CRC specimens.