Project description:RNA profiling was performed in the liver of TRIM24-C52/55A knockin mice fed the high fat diet to identify key downstream targets of TRIM24.
Project description:The transcriptional coregulator Trim24 (formerly known as TIF1a) functions in mice as a liver-specific tumor suppressor. Mice carrying a null mutation in the Trim24 gene all develop hepatocellular carcinoma (HCC). We used microarrays to identify the alterations in gene expression patterns associated with loss of Trim24 and consequent HCC development. Experiment Overall Design: Five independent liver tumor (HCC) samples taken from five Trim24 knockout (KO) mice and five normal liver tissue samples taken from wild-type (WT) littermate controls were used for RNA extraction and hybridization on Affymetrix microarrays.
Project description:The transcriptional coregulator Trim24 (formerly known as TIF1a) functions in mice as a liver-specific tumor suppressor. Mice carrying a null mutation in the Trim24 gene all develop hepatocellular carcinoma (HCC). We used microarrays to identify the alterations in gene expression patterns associated with loss of Trim24 and consequent HCC development. Keywords: normal-tumor comparison
Project description:Purpose: berrantly high expression of TRIM24 occurs in human cancers, including hepatocellular carcinoma. In contrast, TRIM24 in the mouse is reportedly a liver-specific tumor suppressor. To address this dichotomy and uncover direct regulatory functions of TRIM24 in vivo, we developed a new mouse model that lacks expression of all Trim24 isoforms, as the previous model expresses normal levels of Trim24 lacking only exon 4. Methods: To produce germline-deleted Trim24dlE1 mice, deletion of the promoter and exon 1 of Trim24 was induced in Trim24LoxP mice by crossing with a zona pellucida 3-Cre line for global deletion. Liver-specific deletion (Trim24hep) was achieved by crossing with an Albumin-Cre line. Phenotypic analyses were complemented by protein, gene-specific and global RNA expression analyses and quantitative chromatin immunoprecipitation. Results:Global loss of Trim24 disrupted hepatic homeostasis in 100% of mice with highly significant, decreased expression of oxidation/reduction, steroid, fatty acid and lipid metabolism genes, as well as increased expression of genes in unfolded protein, endoplasmic reticulum stress and cell cycle pathways. Trim24dlE1/dlE1 mice have markedly depleted visceral fat and, like Trim24hep/hep mice, spontaneously develop hepatic lipid-filled lesions, steatosis, hepatic injury, fibrosis and hepatocellular carcinoma. Conclusions: TRIM24, an epigenetic co-regulator of transcription, directly and indirectly represses hepatic lipid accumulation, inflammation, fibrosis and damage in the murine liver. Complete loss of Trim24 offers a model of human nonalcoholic fatty liver disease, steatosis, fibrosis and development of hepatocellular carcinoma in the absence of high-fat diet or obesity.
Project description:Conditional overexpression of histone reader Tripartite motif containing protein 24 (TRIM24) in mouse mammary epithelia (Trim24COE) drives spontaneous development of carcinosarcoma tumors, lacking ER, PR and HER2. Human carcinosarcomas or metaplastic breast cancers (MpBC) are a rare, chemorefractory subclass of triple-negative breast cancers (TNBC). Comparison of Trim24COE carcinosarcoma morphology, TRIM24 protein levels and a derived Trim24COE gene signature revealed strong correlation with human MpBC tumors and MpBC xenograft (PDX) models. Global and single-cell tumor profiling revealed Met as a direct oncogenic target of TRIM24, leading to aberrant PI3K/mTOR activation. Pharmacological inhibition of these pathways in primary Trim24COE tumor cells and TRIM24-PROTAC treatment of MpBC PDX tumorspheres revealed the therapeutic potential of targeting TRIM24. Altogether, global expression, single-cell immunophenotyping and mechanistic studies of tumors and MpBC PDX nominated TRIM24-activated c-MET/PI3K/mTOR pathways and TRIM24, which were validated as potential MpBC therapeutic targets.
Project description:Recent genetic studies in mice have established a key role for the nuclear receptor coregulator Trim24 in liver tumor suppression and provided evidence that Trim24 suppresses hepatocarcinogenesis by inhibiting retinoic acid receptor alpha (Rara)-dependent transcription and cell proliferation. However, it is unknown which downstream targets of Rara regulated by Trim24 are critical for tumorigenesis. We report here that loss of Trim24 results in the overexpression of interferon (IFN)/STAT pathway genes in the liver, a process that occurs early in tumorigenesis and is more pronounced in tumors, despite the enhanced expression, late in the disease, of negative regulators such as Usp18, Socs1 and Socs2. Remarkably, Rara haplodeficiency, which was previously shown to suppress tumor development in Trim24-/- mice, also suppresses overexpression of the IFN/STAT pathway, thus providing evidence for a cross-pathway control that may be relevant to the transformation process. Biochemical studies revealed that Trim24 binds to the retinoic acid (RA)-responsive element in the Stat1 promoter in a RA-dependent manner and represses RA-induced transcription from this promoter. Together, these results identify Trim24 as a novel regulator of the IFN/STAT pathway and indicate that Trim24-mediated repression of the IFN/STAT signaling through Rara inhibition may play a critical role in preventing liver cancer. Generation of Trim24-/- mice has been described previously (Khetchoumian et al., 2007) by gene disruption. To generate compound mutant mice with a single allele of Rara deleted in the Trim24 -/- mutant background, we crossed Trim24 -/- mice with Rara+/- mice. The resulting Trim24+/- Rara+/- mice were generated in the hybrid (C57BL/6 (60%), 129/Sv (40%)) genetic background. These double heterozygous Trim24+/- Rara+/- mice were intercrossed to generate Trim24 -/-, Trim24 -/- Rara+/- and wild-type mice. Transcriptional profiling of mice at 5-weeks and 14-weeks of age.
Project description:TRIM24 and TRIM33 interact to form a corepressor complex that suppresses murine hepatocellular carcinoma (HCC). TRIM24 and TRIM33 cooperatively repress retinoic acid receptor dependent activity of VL30 retro-transposons in hepatocytes in vivo. In TRIM24 knockout hepatocytes, VL30 long terminal repeats (LTRs) generate enhancer (e)RNAs and act as surrogate promoter and enhancer elements deregulating expression of neighbouring genes. We show that a VL30 LTR-derived eRNA is essential to activate the lipocalin 13 gene in hepatocytes in vivo. A further consequence of VL30 de-repression is the accumulation of retro-transcribed VL30 DNA in the cytoplasm of TRIM24-mutant hepatocytes and activation of the viral defence/interferon response. VL30 activation therefore modulates gene expression via the enhancer activity of the LTRs and by activation of the interferon response. Both of these processes are genetically linked to HCC development suggesting that VL30 repression by TRIM24 plays an important role in tumour suppression. RNA profiles in liver of wild type (WT) and Trim24-/- mice by deep sequencing using Illumina GAIIx.
Project description:TRIM24 and TRIM33 interact to form a corepressor complex that suppresses murine hepatocellular carcinoma (HCC). TRIM24 and TRIM33 cooperatively repress retinoic acid receptor dependent activity of VL30 retro-transposons in hepatocytes in vivo. In TRIM24 knockout hepatocytes, VL30 long terminal repeats (LTRs) generate enhancer (e)RNAs and act as surrogate promoter and enhancer elements deregulating expression of neighbouring genes. We show that a VL30 LTR-derived eRNA is essential to activate the lipocalin 13 gene in hepatocytes in vivo. A further consequence of VL30 de-repression is the accumulation of retro-transcribed VL30 DNA in the cytoplasm of TRIM24-mutant hepatocytes and activation of the viral defence/interferon response. VL30 activation therefore modulates gene expression via the enhancer activity of the LTRs and by activation of the interferon response. Both of these processes are genetically linked to HCC development suggesting that VL30 repression by TRIM24 plays an important role in tumour suppression. Examination of H3k4me3 and RNA pol II in liver by deep sequencing.