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: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 Sequence library of miRNAs from a single sample of human foetal mesenchymal stem cells. Results tested and confirmed by northern blotting. Please note that only raw data files are available for the embryonic and neual samples and thus, directly submitted to SRA (SRX547311, SRX548700, respectively under SRP042115/PRJNA247767)
Project description:The mechanisms involved in promoting metastasis of pancreatic ductal adenocarcinoma have yet to be elucidated. Here, we show that AnnexinA2 regulates the secretion of Semaphorin3D from pancreatic tumor cells allowing it to bind to its receptor PlexinD1 on the surface of the tumor cell, which induces invasion and metastasis. Knockdown of AnnexinA2 or Semaphorin3D decreases the metastatic potential of pancreatic tumor cells, while over expression of AnnexinA2 or Semaphorin3D is sufficient to rescue the invasion capacity of these cells. Clinically, we found that Semaphorin3D expression correlates with poor survival and increased metastatic potential in human PDA patients. This study identified a novel axon guidance pathway downstream of AnnexinA2 that can be targeted in the treatment of metastatic pancreatic cancer. Two primary pancreatic tumor cell lines were analyzed. The first primary line was derived from a KrasG12D/p53172H/Pdx-1Cre mouse, which served as the reference sample. The second primary line was derived from a KrasG12D/p53R172H/Pdx-1Cre/AnxA2-/- mouse.
Project description:When pancreatic cancer cells metastasize to the liver, resident hepatic stellate cells release retinoic acid. Attached is an analysis of retinoic acid-induced genes in the highly metastatic murine pancreatic cancer cell line Ink4a