Project description:Despite the efforts in defining the molecular mechanisms for the drug resistance in colorectal cancers, little is known about the roles of microRNAs. With microarray containing 723 microRNAs, we examined effect of 5-fluorouracil (5-FU) on the microRNA expression. Respond to 5-FU, we identify two microRNAs, miR-19b and miR-21, that were differentially expressed in 5-FU resistant colon cancer cells derived from KM12C and DLD-1.
Project description:The synergism between c-MYC and miR-17-19b, a truncated version of the miR-17-92 cluster, is well documented during tumor initiation. However, little is known about miR-17-19b function in established cancers. Here we investigate the role of miR-17-19b in c-MYC-driven lymphomas by integrating SILAC-based quantitative proteomics, transcriptomics and 3’ UTR analysis upon miR-17-19b overexpression. We identify over one hundred novel miR-17-19b targets, of which 40% are co-regulated by c-MYC. Down-regulation of a new miR-17/20 target Chek2 increases the recruitment of HuR to c-MYC transcripts, resulting in the inhibition of c-MYC translation and thus interfering with in vivo tumor growth. Hence, in established lymphomas, miR-17-19b fine-tunes c-MYC activity through a tight control of its function and expression, ultimately ensuring cancer cell homeostasis. Our data highlight the plasticity of miRNA function, reflecting changes in the mRNA landscape and 3’ UTR shortening at different stages of tumorigenesis.
Project description:Despite the efforts in defining the molecular mechanisms for the drug resistance in colorectal cancers, little is known about the roles of microRNAs. With microarray containing 723 microRNAs, we examined effect of 5-fluorouracil (5-FU) on the microRNA expression. Respond to 5-FU, we identify two microRNAs, miR-19b and miR-21, that were differentially expressed in 5-FU resistant colon cancer cells derived from KM12C and DLD-1. DLD-1, DLD-1/R, KM12C, and KM12C/R cells were plated at 1 × 105 cells/well. After pre-culture, cells were treated with 60 uM of 5-FU for 72 h. This was the same condition as the analysis of cell cycle. RNAs were collected before (0 h) and after the treatment of 5-FU (72 h).
Project description:We analyzed the differentially regulated genes in 5-fluorouracil-resnstant human colon cancer cells to discover novel biomarkers involved in 5-FU resistance in colorectal cancer.
Project description:Several members from microRNA 17-92 cluster, i.e. miR-19a, miR-19b and miR-20a, were found up-regulated in human epidermal keratinocytes at wound-edges compared to the intact skin; however their biological role in keratinocytes during wound repair has not been studied. To study the genes regulated by miR-19a, miR-19b and miR-20a, we transfected miRNA specific mimics, i.e. pre-miR-19a, pre-miR-19b or pre-miR-20a into human primary epidermal keratinocytes to overexpress them. We performed a global transcriptome analysis of keratinocytes upon overexpression of miR-19a or miR-19b or miR-20a using Affymetrix arrays.
Project description:miR-19b was up-regulated with hepatocellular carcinoma. We compared the transcriptional profile of Hep 3B transfected with miR-19b inhibitor with Hep3B transfected with control to identify genes affected by miR-19b knockdown.
Project description:An increasing number of studies have shown that long noncoding RNA (lncRNA) dysregulation plays an important role in development of various cancers, including colon cancer. Nonetheless, the potential mechanisms of lncRNA in regorafenib-resistance remain unclear. Our research revealed the lncRNA AC069513.3 (MIR570MG) increased in regorafenib-resistant colon cancer cells compared to the regorafenib-sensitive cells. Furthermore, lncRNA AC069513.3 (MIR570MG) sponged miR-145, which declined in regorafenib-resistant colon cancer cell lines. More importantly, overexpression of miR-145 hampered cell proliferation and retrieved colon cancer regorafenib-sensitivity, contrary to the function of lncRNA AC069513.3 (MIR570MG). Dual luciferase reporter assay confirmed that miR-145 bound to 3’-UTR of SMAD3, a transcriptional modulator activated by TGFβ, resulting in blockage of TGFβ /SMAD3-mediated cell growth and cycle progression. Furthermore, ectopic expression of miR-145 inhibitor in the parental cells endowed resistance to regorafenib. Conversely, knockdown of AC069513.3 (MIR570MG) impoverished resistance against regorafenib. In summary, our findings suggested that lncRNA AC069513.3 (MIR570MG) promoted regorafenib resistance via releasing SMAD3 from miR-145, leading to activation of SMAD3-mediated signaling pathways. Long noncoding RNA profiling by RT-PCR
Project description:A summary of the work associated to these microarrays is the following: MicroRNAs (miRNAs) are small non-coding RNAs involved in RNA silencing that play a role in many biological processes. They are involved in the development of many diseases, including cancer. Extensive experimental data show that they play a role in the pathogenesis of cancer as well as the development of drug resistance during treatment. MiRNA microarrays of sensitive and MTX-resistant HT29 colon cancer cells were performed. The results were analyzed using the GeneSpring GX11.5 software. Differentially expressed microRNAs in resistant cells were identified and miR-224, which was greatly underexpressed and displayed robust raw signal values, was selected for further studies. Putative targets were predicted using TargetScan 5.1 software and intersected with the data from expression microarrays previously performed. This approach allowed us to identify miR-224 targets that were differentially expressed more than 2-fold in resistant cells. Among them, ARL3, CDS2, DCP2, HSPC159, MYST3 and SLC4A4 were validated at the mRNA level by qRT-PCR. Functional assays using an anti-miR against miR-224 desensitized the cells toward MTX, mimicking the resistant phenotype. On the other hand, siRNA treatment against SLC4A4 or incubation of Poly Purine Reverse Hoogsteen (PPRH) hairpins against CDS2 or HSPC159 increased sensitivity to MTX. These results revealed a role for miR-224 and its targets in MTX resistance in HT29 colon cancer cells. KEYWORDS Methotrexate, miRNAs, drug resistance, DHFR Two cell lines are compared in the study, which are HT29 colon cancer cells sensitive to methotrexate and HT29 cells resistant to 10e-5M MTX. Six samples are provided which correspond to 3 samples for the control condition and 3 samples for the resistant condition. Data files from miRNA and mRNA (previously submitted to GEO as GSE11440) microarrays were analyzed with GeneSpring GX11.5 software (Agilent Technologies) to find differentially expressed miRNAs and their cellular target genes in the resistant cell lines compared to their sensitive counterparts.
Project description:miR-19b was up-regulated with hepatocellular carcinoma. We compared the transcriptional profile of Hep 3B transfected with miR-19b inhibitor with Hep3B transfected with control to identify genes affected by miR-19b knockdown. Hep 3B_miR-19b transfected vs Hep 3B_control transfected