Project description:To understand the role of UHRF1 in prostate cancer, we have employed miRNAs microarray expression profiling as a discovery platform to identify miRNAs whose expression is regulated by UHRF1 and have a potential to regulate downstream effectors involved in prostate cancer.
Project description:UHRF1 is a major regulator of epigenetic mechanism and is overexpressed in various human malignancies. In this study, we examined the involvement of UHRF1 in aberrant DNA methylation in colorectal cancer (CRC). In CRC cells, transient UHRF1 knockdown rapidly induced DNA demethylation across entire genomic regions, including CpG islands, gene bodies and repetitive elements. Nonetheless, UHRF1 depletion only minimally reversed CpG island hypermethylation-associated gene silencing. However, the combination of UHRF1 depletion and histone deacetylase (HDAC) inhibition synergistically reactivated the silenced genes and strongly suppressed CRC cell proliferation. Our results suggest that (i) maintenance of DNA methylation in CRC cells is highly dependent on UHRF1; (ii) UHRF1 depletion rapidly induces DNA demethylation, though it is insufficient to fully reactivate the silenced genes; and (iii) dual targeting of UHRF1 and HDAC may be an effective new therapeutic strategy.
Project description:UHRF1 is a major regulator of epigenetic mechanism and is overexpressed in various human malignancies. In this study, we examined the involvement of UHRF1 in aberrant DNA methylation in colorectal cancer (CRC). In CRC cells, transient UHRF1 knockdown rapidly induced DNA demethylation across entire genomic regions, including CpG islands, gene bodies and repetitive elements. Nonetheless, UHRF1 depletion only minimally reversed CpG island hypermethylation-associated gene silencing. However, the combination of UHRF1 depletion and histone deacetylase (HDAC) inhibition synergistically reactivated the silenced genes and strongly suppressed CRC cell proliferation. Our results suggest that (i) maintenance of DNA methylation in CRC cells is highly dependent on UHRF1; (ii) UHRF1 depletion rapidly induces DNA demethylation, though it is insufficient to fully reactivate the silenced genes; and (iii) dual targeting of UHRF1 and HDAC may be an effective new therapeutic strategy.
Project description:UHRF1 is a major regulator of epigenetic mechanism and is overexpressed in various human malignancies. In this study, we examined the involvement of UHRF1 in aberrant DNA methylation in colorectal cancer (CRC). In CRC cells, transient UHRF1 knockdown rapidly induced DNA demethylation across entire genomic regions, including CpG islands, gene bodies and repetitive elements. Nonetheless, UHRF1 depletion only minimally reversed CpG island hypermethylation-associated gene silencing. However, the combination of UHRF1 depletion and histone deacetylase (HDAC) inhibition synergistically reactivated the silenced genes and strongly suppressed CRC cell proliferation. Our results suggest that (i) maintenance of DNA methylation in CRC cells is highly dependent on UHRF1; (ii) UHRF1 depletion rapidly induces DNA demethylation, though it is insufficient to fully reactivate the silenced genes; and (iii) dual targeting of UHRF1 and HDAC may be an effective new therapeutic strategy.
Project description:UHRF1 is a major regulator of epigenetic mechanism and is overexpressed in various human malignancies. In this study, we examined the involvement of UHRF1 in aberrant DNA methylation in colorectal cancer (CRC). In CRC cells, transient UHRF1 knockdown rapidly induced DNA demethylation across entire genomic regions, including CpG islands, gene bodies and repetitive elements. Nonetheless, UHRF1 depletion only minimally reversed CpG island hypermethylation-associated gene silencing. However, the combination of UHRF1 depletion and histone deacetylase (HDAC) inhibition synergistically reactivated the silenced genes and strongly suppressed CRC cell proliferation. Our results suggest that (i) maintenance of DNA methylation in CRC cells is highly dependent on UHRF1; (ii) UHRF1 depletion rapidly induces DNA demethylation, though it is insufficient to fully reactivate the silenced genes; and (iii) dual targeting of UHRF1 and HDAC may be an effective new therapeutic strategy.
Project description:UHRF1 (Ubiquitin-like, containing PHD and RING finger domains, 1) recruits DNMT1 to hemimethylated DNA during replication, is essential for maintaining DNA methylation patterns during cell division and is suggested to direct additional repressive epigenetic marks. Uhrf1 mutation in zebrafish results in multiple embryonic defects including failed hepatic outgrowth, but the epigenetic basis of these phenotypes is not known. We find that DNA methylation is the only epigenetic mark that is depleted in uhrf1 mutants and make the surprising finding that despite the reduced organ size in uhrf1 mutants, genes regulating DNA replication and S-phase progression were highly upregulated. Further, there is a striking increase in BrdU incorporation in uhrf1 mutant cells, and they retained BrdU labeling over several days, indicating they are arrested in S-phase. Moreover, some of the label retaining nuclei co-localized with TUNEL positive nuclei, suggesting that arrested cells are responsible for apoptosis. Importantly, dnmt1 mutation phenocopies the S-phase arrest and hepatic outgrowth defects in uhrf1 mutants and Dnmt1 knock-down enhances the uhrf1 hepatic phenotype. Together, these data indicate that DNA hypomethylation is sufficient to generate the uhrf1 mutant phenotype by promoting an S-phase arrest. We thus propose that cell cycle arrest is a mechanism to restrict propagation of epigenetically deranged cells during embryogenesis. Genome-wide expression profiling was performed on 2 uhrf1 mutant and 2 wildtype zebrafish larvae (120 hours post fertilization) by using Zebrafish Genome Array (Affymetrix) according to manufacturer's instruction.
Project description:Aurora-A has attracted a great deal of interest as a potential therapeutic target. However, the outcomes of inhibitors targeting Aurora-A are not as favorable as expected, and the basis of their ineffectiveness remains unknown. Here, we found that signal transducer and activator of transcription 1 (STAT1) was highly expressed in colorectal cancer (CRC) xenograft mouse models that were resistant to alisertib, an Aurora-A inhibitor, in an interferon/Janus kinase-independent manner, suggesting an unconventional mechanism regulating STAT1 expression. Unexpectedly, we found that alisertib disrupted Aurora-A binding with ubiquitin-like with plant homeodomain and ring finger domain 1 (UHRF1), leading to UHRF1-mediated ubiquitination and degradation of DNA methyltransferase 1 (DNMT1), which in turn resulted in demethylation of the CpG islands in the STAT1 promoter and STAT1 overexpression. Simultaneous silencing of Aurora-A and UHRF1 prevented STAT1 overexpression and effectively inhibited CRC growth. Hence, concomitant targeting of Aurora-A and UHRF1 can be a promising therapeutic strategy for cancer patients.
Project description:We used microarrays to explore the expression profile from cells expressing wild type and UHRF1 S674A mutant. HeLa cells expressing UHRF1 WT and S674A mutant showed similar gene expression pattern without significant affecting the transcription of DNA repari genes. UHRF1 was depleted in HeLa cells by shRNA treatment. Total RNA was purified and used to determine the global gene transcription profiles by microarray assays. The UHRF1-related genes expression profiles were compared among control cells, UHRF1-depleted cells, UHRF1 WT reconstituting cells and UHRF1 S674A mutant reconstituting cells.
Project description:Deletion of Uhrf1 resulted in stage 1-specific defects during iNKT cell development. To investigate the molecular mechanism, we sorted WT and Uhrf1-KO stage 1 iNKT cells and performed RNA-seq. By comparing gene expression profile, we found metabolic defects in Uhrf1-KO stage 1 iNKT cells. The expression of CD71 (Tfrc), two subunits of CD98 (Slc3a2 and Slc7a5) and Glut3 (Slc2a3) was reduced in stage 1 iNKT cells. Besides, the downstream pathways of AKT-mTOR axis were significantly reduced. Collectively, our results suggest that Uhrf1 is required for iNKT cell development by regulating the Akt-mTOR signaling pathway. We first sorted WT and Uhrf1-KO stage 1 iNKT cells, extracted the mRNA and performed RNA-seq. We then analyzed the differentially expressed genes and performed KEGG pathway analysis. We used RT-PCR to verify the expression of the key nutrient related genes (Tfrc, Slc3a2, Slc7a5 and Slc2a3) and used flow cytometry to test the protein level of metabolic related molecules. Besides, we also analyzed the expression of genes of mTOR downstream pathways to demonstrate that Uhrf1 mediated AKt-mTOR axis regulates iNKT cell development.