Project description:For androgen-independent prostate cancer (AIPC), the current treatment is limited and the prognosis is poor. We previously found miR-200b could inhibit androgen independent proliferation ability of prostate cancer cells, but the mechanism is unclear. MiRNAs plays their role by blocking translation through base-pairing with complementary mRNA and by promoting degradation of target mRNA. Unraveling the miRNA translational silencing network remains a challenge in part because a single miRNA can inhibit multiple mRNA targets and because a single mRNA can be regulated by several distinct miRNAs that act cooperatively. However, proteomics methods provide us useful tools to unravel the target genes network. This study identified the target genes of miR-200b in AIPC. It helps us to understand the mechanism of AIPC and applies several new candidate targets of AIPC treatment.
Project description:We used miRNA expression arrays and integrated analysis to study mucoepidermoid carcinomas (MEC) to identify potential drivers involved with its pathogenesis. Normal salivary glands were used as controls.
Project description:Microarray‐based techniques are being used to obtain miRNA and gene expression signatures associated with different samples. In order to deepen our understanding of BRCA1-associated tumorigenesis, we integrated data from microarray experiments to obtain significant miRNA-mRNA relationships associated with the presence of the BRCA1 gene. We obtained significant miRNA-gene-pathway relationships underlying the array signatures. Furthermore, we have demonstrated that miR-146a, miR-99b and miR-205, induced in HCC1937 BRCA1-expressing cells, commonly regulate the TRAF2 gene, a key regulator of NF-κB and MAPK pathways. In addition, re-expression of miR-146a, miR-99b or miR-205 in HCC1937 BRCA1-null cells was sufficient to modulate NF-κB activity. Thus, integration between miRNA-mRNA expression data allowed us to define genes and pathways controlled by miRNAs induced in the context of BRCA1 expression.
Project description:Micro RNAs (miRNAs) miR-130a, miR-203 and miR-205 are jointly downregulated in prostate cancer and act as repressors of AR-signaling. MiRNAs are small non-coding RNAs that regulate the expression of specific mRNA targets mainly by translational repression, mRNA deadenylation or cleavage. Reconstitution of these lost miRNAs in the LNCaP PCa cell line cause morphology changes, growth arrest, and apoptosis, increasing when the miRNAs were co-expressed. This series identifies direct targets of miR-130a, miR-203, and miR-205 by AGO2-RNA co-immunoprecipitation as described by (Beitzinger et al. 2007) upon miRNA reconstitution in LNCaP cells and analyzing AGO2-bound mRNAs using Affymetrix Genechips. Relative levels of AGO2 bound versus total RNA expression were compared between miRNA reconstituted and miR-scr transfected samples.
Project description:Melanoma is the most aggressive form of skin cancer with estimated 48,000 deaths worldwide. The polyphenol curcumin derived from the plant Curcuma longa is well known for its anti-inflammatory and anti-cancerogenic properties. Accordingly, dietary intake of this compound may be suitable for melanoma prevention. However, how this compound affects basic cellular mechanisms in developing melanoma still remains elusive. Therefore, the aim of this study was to investigate for the first time the impact of oral curcumin administration on the miRNA signature of engrafting melanoma. For this purpose, the effects of a 4% curcumin diet on murine B78H1 melanoma were tested in a flank model. Curcumin diet or standard chow (control) was administered two weeks prior to tumor initiation until termination of the experiment. Highly significant chip-based miRNA array analysis was deployed to detect alterations in the miRNA signature of the tumors. Curcumin treatment significantly reduced the growth of the flank tumors. Furthermore the miRNA expression signature in tumors was substantially altered by curcumin intake with mmu-miR-205-5p over 100 times higher expressed when compared to controls. Putative targets of curcumin-induced up-regulated miRNAs were enriched in o-glycan biosynthesis, endoplasmatic reticulum protein processing and different cancer-related pathways. These findings demonstrate a profound alteration of the miRNA expression signature in engrafting curcumin-treated melanoma with mmu-miR-205-5p being up-regulated most significantly.
Project description:Clear cell renal cell carcinomas (ccRCC) are characterized by arm-wide chromosomal alterations. Loss at 14q is associated with disease aggressiveness in ccRCC, which responds poorly to chemotherapeutics. The 14q locus contains one of the largest miRNA clusters in the human genome; however, little is known about the contribution of these miRNAs to ccRCC pathogenesis. In this regard, we investigated the expression pattern of selected miRNAs at the 14q32 locus in TCGA kidney tumors and in ccRCC cell lines. We validated that the miRNA cluster is downregulated in ccRCC (and cell lines) as well as in papillary kidney tumors relative to normal kidney tissues and primary renal proximal tubule epithelial (RPTEC) cells. We demonstrated that agents modulating expression of DNMT1 (e.g., 5-Aza-deoxycytidine) could modulate miRNA expression in ccRCC cell lines. Lysophosphatidic acid (LPA, a Lysophospholipid mediator elevated in ccRCC) not only increased labile iron content but also modulated expression of 14q32 miRNAs. Through an overexpression approach targeting a subset of 14q32 miRNAs (specifically at subcluster A: miR-431, miR-432, miR-127, and miR-433) in 769-P cells, we uncovered changes in cellular viability and claudin-1, a tight junction marker. A global proteomic approach was implemented using these miRNA overexpressing cell lines which uncovered ATXN2 as a highly downregulated target, which has a role in chronic kidney disease pathogenesis. Collectively, these findings support a contribution of miRNAs at 14q32 in ccRCC pathogenesis.
