Role of miR-19b and its target mRNAs on 5-fluorouracil resistance in colon cancer cells
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: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: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. Overall design: Expression profiling of primary human epidermal keratinocytes transfected with 20nM miR-19a mimics (pre-miR-19a) or 20nM miR-19b mimics (pre-miR-19b) or 20nM miR-20a mimics (pre-miR-20a) or 20nM control oligos (pre-miR-Ctrl) for 24 hours (biological triplicates in each group) was performed using Affymetrix GeneTitan system.
Project description:5-Fluorouracil (5-FU) is a widely used chemotherapeutic drug in colorectal cancer. Previous studies showed that 5-FU modulates RNA metabolism and mRNA expression. In addition, it has been reported that 5-FU incorporates into the RNAs constituting the translational machinery and that 5-FU affects the amount of some mRNAs associated with ribosomes. However, the impact of 5-FU on translational regulation remains unclear. Using translatome profiling, we report that a clinically relevant dose of 5-FU induces a translational reprogramming in colorectal cancer cell lines. Comparison of mRNA distribution between polysomal and non-polysomal fractions in response to 5-FU treatment using microarray quantification identified 313 genes whose translation was selectively regulated. These regulations were mostly stimulatory (91%). Among these genes, we showed that 5-FU increases the mRNA translation of HIVEP2, which encodes a transcription factor whose translation in normal condition is known to be inhibited by mir-155. In response to 5-FU, the expression of mir-155 decreases thus stimulating the translation of HIVEP2 mRNA. Interestingly, the 5-FU-induced increase in specific mRNA translation was associated with reduction of global protein synthesis. Altogether, these findings indicate that 5-FU promotes a translational reprogramming leading to the increased translation of a subset of mRNAs that involves at least for some of them, miRNA-dependent mechanisms. This study supports a still poorly evaluated role of translational control in drug response. Overall design: 8 total samples were analyzed. We generated the following pairwise comparisons: -5FU polysome vs -5FU non-polysome +5FU polysome vs +5FU non-polysome +5FU polysome vs -5FU polysome. Genes and exons with an fold change >= 1.5 and a p-value <= 0.05 were selected.
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:Over 40 % of microRNAs are located in introns of coding genes, and many intronic microRNAs are co-regulated with their host genes. In such cases of co-regulation, the products of host genes and their intronic microRNAs can cooperate to coordinately regulate biologically important pathways. Therefore, we screened intronic microRNAs dysregulated in liver of obese mouse models to identify previously uncharacterized coding host genes that may contribute to the pathogenesis of obesity-associated insulin resistance and type 2 diabetes mellitus. Our approach identified that expression of both Ectodysplasin A (Eda), the causal gene of X-linked hypohidrotic ectodermal dysplasia (XLHED; MIM 305100) and its intronic microRNA, miR-676, was strongly increased in liver of obese mouse models. Moreover, hepatic EDA expression is increased in obese human subjects, reduced upon weight loss, and its hepatic expression correlates with systemic insulin resistance. Eda expression in murine liver is controlled via PPARg activation, increases in circulation and promotes JNK activation and inhibitory serine phosphorylation of IRS1 in skeletal muscle. Consistently, bi-directional modulation of hepatic Eda expression in mouse models affects systemic glucose metabolism with alterations of muscle insulin signaling, revealing a novel role of EDA as an obesity-associated hepatokine, which impairs insulin sensitivity in skeletal muscle.
Project description:Bone marrow microenvironment in MM contains a unique miR signature, which is partially present and detectable in the peripheral blood. A subset of miRs (let-7i, miR-106b, miR-15a, and miR16) shows aberrant expression in the precursor lesion of MGUS, while aberrant expression of other miRs (let-7a, miR-15a/b, miR-19b, miR-20a, miR-21, miR-223, and miR-361) is associated with cell proliferation and disease progression. miRNA profiling was performed using Agilent miRNA array platforms with RNAs isolated from the bone marrow supernatant of multiple myeloma.
Project description:5-Fluorouracil (5-FU) is a commonly used drug for the treatment of malignant cancers. However, approximately 80% of patients undergoing 5-FU treatment suffer from gastrointestinal mucositis. The aim of this report was to identify the critical molecule involved in 5-FU-induced intestinal mucositis. Our data showed that 5-FU induced inflammation in the small intestine, characterized by the increased intestinal wall thickness and crypt length and the decreased villus height. Network analysis of 5-FU-affected genes by transcriptomic tool showed that the expression of genes was regulated by nuclear factor-κB (NF-κB), and NF-κB was the central molecule in the 5-FU-regulated biological network. NF-κB activity was activated by 5-FU in the intestine, which was judged by bioluminescence imaging and immunohistochemical staining. However, 5-aminosalicylic acid (5-ASA) inhibited 5-FU-induced NF-κB activation and proinflammatory cytokine production. Moreover, 5-FU-induced histological changes were improved by 5-ASA. In conclusion, our findings suggested that NF-κB was the critical molecule associated with the pathogenesis of 5-FU-induced mucositis, and inhibition of NF-κB activity ameliorated the mucosal damage caused by 5-FU. Overall design: Male mice were injected intraperitoneally with 5-FU (100 mg/kg). Two days later, intestines were collected for RNA extraction. 3 5-FU-treated replicates and 3 mock replicates.
Project description:Purpose: MicroRNAs play a prominent role in a variety of physiological and pathological biological processes, including cancer. For rectal cancers, only limited data are available on microRNA expression profiles, while the underlying genomic and transcriptomic aberrations have been firmly established. We therefore aimed to comprehensively map the microRNA expression patterns of this disease. Experimental design: Tumor biopsies and corresponding matched mucosa samples were prospectively collected from 72 patients (68 tumors and 70 normal mucosa) with locally advanced rectal cancers. Total RNA was extracted, and tumor and mucosa microRNA expression profiles were subsequently established for all patients. The expression of selected microRNAs was validated using semi-quantitative real-time PCR. Results: Forty-nine microRNAs were significantly differentially expressed (log2-fold difference >0.5 and P<0.001) between rectal cancer and normal rectal mucosa. The predicted targets for the identified microRNAs were enriched for the following KEGG pathways: Wnt, TGF-beta, mTOR, insulin, MAPK, and ErbB signaling. Between rectal tumor and normal tissue, miR-492, miR-542-5p, miR-584, miR-483-5p, miR-144, miR-2110, miR-652*, miR-375, miR-147b, miR-148a, miR-190, miR-26a/b, and miR-338-3p were found to be differentially expressed. Of clinical impact, miR-135b expression correlated significantly with overall survival that could be validated in a larger multicenter patient set (n=94). Conclusion: The comprehensive analysis of the rectal cancer microRNAome uncovered novel microRNAs and pathways associated with rectal cancer. This information contributes to a detailed view of rectal cancer. The identification and validation of miR-135b will help to identify novel molecular targets and pathways for therapeutic exploitation. Paired samples from rectal tumor and matched normal samples. Included are also 2 technical replicates.
Project description:MicroRNAs (miRNAs) have emerged as important gene regulators and are recognized as key players in tumorigenesis. miR-143 is reported to be down-regulated in several cancers, but knowledge of its targets in colon cancer remains limited. To investigate the role of miR-143 in colon cancer, we have employed a microarray based approach to identify miR-143 targets. Based on seed site enrichment analyses and unbiased word analyses, we found a significant enrichment of miRNA binding sites in the 3’-untranslated regions (UTRs) of transcripts down-regulated upon miRNA overexpression. Here we identify Hexokinase 2 (HK2) as a direct target of miR-143 and show that re-introduction of miR-143 in the colon cancer cell line DLD-1 results in a decreased lactate secretion, indicating that miR-143 down-regulation of HK2 affects glucose metabolism in colon cancer cells. DLD-1 cells were transfected with 50 nM miR-143 duplex or mock transfected. Total RNA was harvested 24 hours post-transfection and analyzed on Affymetrix HG-U133 Plus 2.0 human arrays.