Project description:Lack of specific markers for invasive uveal melanoma cells prevents early diagnosis of metastasis, while no systemic treatment options are available for patients with disseminated uveal melanomas. Intra-tumor heterogeneity has been recognized in numerous cancers as the main cause of metastasis development and therapy resistance. However, in uveal melanomas the specific subpopulations and their biological function which influence tumor behavior remained unknown. Here, using scRNA-seq analysis of six different primary uveal melanomas, we uncovered previously unrecognized intratumor heterogeneity. We localized diverse tumor-associated populations and transcriptional states in primary uveal melanomas. We also unraveled a gene regulatory network underlying a poor prognosis melanoma state. Heterogeneity was demonstrated in uveal melanoma tissue using the RNAscope assay. Thus, single-cell analysis offers an unprecedented view of intratumor heterogeneity in primary uveal melanoma, identified bona fide biomarkers for metastatic cells in the primary tumor, and unravel targetable modules driving metastase formation and growth, with critical implications for prognosis and therapeutic opportunity.
Project description:MicroRNAs (miRNAs) are a class of endogenous non-coding RNAs of about 22 nt in length. Uveal melanoma is the most common intraocular malignant tumor in adults. Our previous result of microarray analysis showed that miR-142-3p was distinctly downregulated in uveal melanoma cells on which miR-142-3p was speculated to have important regulatory effect. In order to better understand the function of miR-142-3p in uveal melanoma and identify its gene targets, we performed transcriptomic microarray analysis. This was done by comparing gene expression profile changes in uveal melanoma cells transfected with miR-142-3p with that transfected with a negative control.
Project description:Karyotyping by SNP array of primary uveal melanoma samples, uveal melanoma cell lines and normal controls The Human660WQuad v1.0 DNA Analysis Bead Chip and kit were used for high resolution molecular karyotyping of DNA isolated from snap-frozen primary uveal melanoma tissue isolated from enucleated eyes.
Project description:Uveal melanoma is a highly aggressive cancer with a strong propensity for metastasis, yet little is known about the biological mechanisms underlying this metastatic potential. We recently showed that most metastasizing uveal melanomas, which exhibit a class 2 gene expression profile, contain inactivating mutations in the tumor suppressor BAP1. The aim of this study was to investigate the role of BAP1 in uveal melanoma progression. To that end, uveal melanoma cells were studied following stable shRNA-mediated depletion of BAP1. RNA was isolated from three independent uveal melanoma cell lines each stably depleted using shRNA for either BAP1 or the control gene GFP. Two biological replicates were performed for each cell line.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes
Project description:Gene expression in primary uveal melanoma cells and normal cell controls The HumanHT-12 v3 gene expression microarray (Illumina) was used to analyze RNA isolated from snap-frozen primary uveal melanoma tissue isolated from enucleated eyes and from normal cell controls.
