Role of miR-19b and its target mRNAs on 5-fluorouracil resistance in colon cancer cells
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ABSTRACT: 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: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: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:Systemic sclerosis (SSc) is a chronic autoimmune disease characterized with fibrosis of skin and multiple vital organs, but the immunological pathogenesis of SSc remains largely unknown. We show here that microRNA-19b (miR-19b) promotes IL-9-producing CD4+ T cells (Th9) that exacerbate SSc. Specifically, TGF-b plus IL-4 induced expression of TNF receptor associated factor 6 (TRAF6) through phosphorylated Smad3 linker region site Serine 213 (p-Smad3L-Ser213) and activated it through K63 ubiquitination by suppressing the leucine-rich-repeat-containing protein 3 (NLRC3). TRAF6 consequently formed complex with and activated TGF-b activated kinase 1 (TAK1). TAK1 promoted nuclear factor kappa B (NFκB) p65 activation, which then specifically upregulated miR-19b. miR-19b activated Il9 gene expression and promoted Th9 differentiation by directly targeting and suppressing atypical E2F family member E2f8 gene, a repressor for Il9 gene transcription. Importantly, Th9 cells played a critical role in the development and pathogenesis of experimental SSc by promoting the fibrosis in mice induced with Bleomycin. miR-19b and IL-9 were increased in CD4+ T cells in experimental SSc in mice and also in patients with SSc. Strikingly, inhibition of miR-19b resulted in fewer Th9 cells and attenuated fibrotic manifestations and ameliorated the disease in SSc mice. Our study identifies miR-19b as a key factor of Th9 cells that are involved in the pathogenesis of SSc. Our findings should have clinical implications for patients with SSc.
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
Project description:Lung fibroblasts play a pivotal role in pulmonary fibrosis, a devastating lung diseases, by producing extracellular matrix. MicroRNAs (miRNAs) suppress a lot of genes posttranscriptionally, but the dynamics and the role of miRNAs in activated lung fibroblasts in fibrotic lung has been poorly understood. We found miR-19a, 19b and 20a subcluster expression increased in activated lung fibroblasts as the fibrosis progression. To elucidate whether fibroblast-specific intervention against miR-19a, 19b and 20a subcluster modulates pathogenic activation of lung fibroblasts in vivo, we intratracheally-transferred the subcluster-overexpressed fibroblasts into bleomycin-treated lungs and performed global transcriptome analysis.
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: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:Patients with advanced colorectal cancer (CRC) are commonly treated with systemic combination therapy but suffer eventually from drug resistance. MicroRNAs (miRNAs) are suggested to play a role in treatment resistance of CRC. We studied whether restoring downregulated miR-195-5p and 497-5p sensitize CRC cells to currently used chemotherapeutics 5-fluorouracil, oxaliplatin and irinotecan. Sensitivity to 5-FU, oxaliplatin and irinotecan before and after transfection with miR-195-5p and miR-497-5p mimics was analyzed in CRC cell lines HCT116, RKO, DLD-1 and SW480. Mass spectrometry based proteomic analysis of transfected and wild-type cells was used to identify targets involved in sensitivity to chemotherapy. Proteomic analysis revealed 181 proteins with significantly altered expression after transfection with miR-195-5p mimic in HCT116 and RKO, including 118 downregulated and 63 upregulated proteins. After transfection with miR-497-5p mimic, 130 proteins were significantly downregulated and 102 were upregulated in HCT116 and RKO (P<0.05 and FC<-3 or FC>3). CHUK and LUZP1 were coinciding downregulated proteins in sensitized CRC cells after transfection with either mimic. Resistance mechanisms of these two proteins may be related to nuclear factor kappa-B signaling and G1 cell cycle arrest, respectively. Restoring miR-195-5p and miR-497-5p expression enhanced sensitivity to chemotherapy, mainly oxaliplatin, in CRC cells and could be a promising treatment strategy for patients with mCRC. Proteomics revealed potential targets of these miRNAs involved in sensitivity to chemotherapy.