Project description:To identify miRNAs involved in drug resistance of human breast cancer, a miRNA microarray was performed on 5 cases of drug resistant tissues and 5 cases of drug sensitive tissues.The expression levels of totally 2019 miRNAs in 5 pairs of matched, drug resistant and drug sensitive tissues were examined by microarray. There were 27 differentially expressed miRNAs between drug resistant and drug sensitive tissues were identified of which there were 11 significantly up-regulated while the other 16 were down-regulated in drug resistant tissues compared to drug sensitive tissues. It was found that miR-489 was one of the most downregulated miRNAs in drug resistant tissues.
Project description:To identify miRNAs involved in drug resistance of human breast cancer, a miRNA microarray was performed on 10 cases of drug resistant tissues and 10 cases of drug sensitive tissues. There were 29 differentially expressed miRNAs between drug resistant and drug sensitive tissues, including 22 significantly up-regulated and 7 down-regulated RNAs in drug resistant tissues compared to drug sensitive tissues. A signature of five miRNAs, including miR-23a-3p, miR-200c-3p, miR-214-3p, miR-638, and miR-451a was established. A risk score from the miRNA signature was calculated and patients were classified into high-risk and low-risk groups. Compared with the patients with low-risk scores, the patients with high risk scores showed resistant response to chemotherapy in the training, internal testing and independent sets.
Project description:Microparticles (MPs) comprise the major source of systemic RNA including microRNA (miRNA), the aberrant expression of which appears to be associated with stage, progression and spread of many cancers. We have shown MPs to transfer multidrug resistance proteins accross both haematological and and non-haematological cancers. using microarray miRNA profiling analysis we now analyze changes in miRNA profiles of both cancer types following microparticle transfer. We identified certain upregulated miRNAs in both cancer types. Total RNA was extracted and pooled from duplicate experiments for hybridization on Affymetrix microarrays from (i) the parental drug sensitive leukaemia (CEM) or breast cancer (MCF-7) cells, (ii) their Multidrug Resistant strains leukaemia (VLB100) or breast cancer ( DX cells), (iii) the microparticles isolated from the resistant cells: VLBMP or DXMP, and (iv) the cocultured samples: sensitive cell co-incubated with MPs from their resistant cells ( leukaemia: CEM+VLBMP) or(breast cancer: MCF-7+DXMP). We sought to examine the miRNA profiles of the drug sensitve cells after MP transfer from drug resistant cells across leukaemia nd breact cancer cell lines.
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:Background: Non-coding RNAs have been proved to play an essential role in the development and progression of various cancers. However, the functions and mechanisms of non-coding RNA and mRNA in multi-drug resistance of colorectal cancer have not been fully elucidated.Methods: We performed RNA-sequencing to screen differentially expressed non-coding RNA and mRNA in CRC chemo-resistant and chemo-sensitive cell lines. Results: The results showed that 1779 mRNAs, 64 miRNAs, 11 circRNAs and 295 lncRNAs were common differentially expressed in two chemo-resistant cell lines.Conclusions:The results of the study may provide new theories and therapeutic targets for multi-drug resistance in colorectal cancer.
Project description:Tamoxifen is the most widely administered adjuvant first-line hormone therapy for Estrogen receptor α (ERα) positive breast cancer patients. However, one from three patients will develop resistance, while the underlying molecular mechanisms are currently unclear. Recent studies reported that abnormal expression of miRNAs played a role in cancer progress. To study the potential function of miRNAs in tamoxifen resistance, Affymetrix GeneChip® miRNA 3.0 microarray was employed to identify differentially expressed miRNAs between tamoxifen sensitive MCF7 parent (MCF7-Pa) cells and induced resistant (MCF7-Re) cells.