Metformin reverses a precancerous niche featuring cytoplasmic p21WAF1/CIP1-expressing hepatocytes and prevents hepatocellular carcinoma development
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE110524 | GEO | 2020/03/28
REPOSITORIES: GEO
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Project description:Metformin reverses a precancerous niche featuring cytoplasmic p21WAF1/CIP1-expressing hepatocytes and prevents hepatocellular carcinoma development
| PRJNA433926 | ENA
Project description:The cyclin-dependent kinase inhibitor p21WAF1/Cip1 is the prototype downstream effector of the tumor suppressor protein p53. Yet, evidence from human cancer and mice models, imply that p21WAF1/Cip1, under certain conditions, can exercise oncogenic activity. The mechanism behind this behavior is still obscure. Within this context we unexpectedly noticed, predominantly in p53 mutant human cancers, that a subset of highly atypical cancerous cells expressing strongly p21WAF1/Cip1 demonstrated also signs of proliferation. This finding suggests either tolerance to high p21WAF1/Cip1 levels or that p21WAF1/Cip1 per se guided a selective process that led to more aggressive off-springs. To address the latter scenario we employed p21WAF1/Cip1-inducible p53-null cellular models and monitored them over a prolonged time period, using high-throughput screening means. After an initial phase characterized by stalled growth, mainly due to senescence, a subpopulation of p21WAF1/Cip1 cells emerged, demonstrating increased genomic instability, aggressiveness and chemo-resistance. At the mechanistic level unremitted p21WAF1/Cip1 production â??saturatesâ?? the CRL4CDT2 and SCFSkp2 ubiquitin ligase complexes reducing the turn-over of the replication licensing machinery. Deregulation of replication licensing triggered replication stress fuelling genomic instability. Conceptually, the above notion should be considered when anti-tumor strategies are designed, since p21WAF1/Cip1 responds also to p53-independent signals, including various chemotherapeutic compounds. We used microarrays to compare the non-induced and â??escapedâ?? Saos2-p21WAF1/Cip1 Tet-ON cells gene expression profile Multiple arrays for non-induced and â??escapedâ?? Saos2-p21WAF1/Cip1 Tet-ON cells
2016-05-15 | E-GEOD-62166 | biostudies-arrayexpress
Project description:The cyclin-dependent kinase inhibitor p21WAF1/Cip1 is the prototype downstream effector of the tumor suppressor protein p53. Yet, evidence from human cancer and mice models, imply that p21WAF1/Cip1, under certain conditions, can exercise oncogenic activity. The mechanism behind this behavior is still obscure. Within this context we unexpectedly noticed, predominantly in p53 mutant human cancers, that a subset of highly atypical cancerous cells expressing strongly p21WAF1/Cip1 demonstrated also signs of proliferation. This finding suggests either tolerance to high p21WAF1/Cip1 levels or that p21WAF1/Cip1 per se guided a selective process that led to more aggressive off-springs. To address the latter scenario we employed p21WAF1/Cip1-inducible p53-null cellular models and monitored them over a prolonged time period, using high-throughput screening means. After an initial phase characterized by stalled growth, mainly due to senescence, a subpopulation of p21WAF1/Cip1 cells emerged, demonstrating increased genomic instability, aggressiveness and chemo-resistance. At the mechanistic level unremitted p21WAF1/Cip1 production “saturates” the CRL4CDT2 and SCFSkp2 ubiquitin ligase complexes reducing the turn-over of the replication licensing machinery. Deregulation of replication licensing triggered replication stress fuelling genomic instability. Conceptually, the above notion should be considered when anti-tumor strategies are designed, since p21WAF1/Cip1 responds also to p53-independent signals, including various chemotherapeutic compounds.
2016-05-15 | GSE62166 | GEO
Project description:Due to the global obesity epidemic the incidences of nonalcoholic steatohepatitis (NASH) and NASH-related hepatocellular carcinoma (HCC) are on the rise. Non-invasive treatment options for HCC are scarce and innovative therapy regimes are urgently needed. The mechanistic target of rapamycin (mTOR) is of fundamental importance for the regulation of cellular metabolism and mTOR pathway activation is frequently observed in HCCs. However, mTOR inhibition failed to benefit the clinical course of HCC patients, demonstrating the need for a better understanding of the molecular and functional consequences of blocking mTOR signaling in primary liver cancer. To address this, we established a tumor cell-specific inactivation of mTOR in a murine model of non-alcoholic steatohepatitis (NASH)-driven HCC. After 30 weeks of diet, tumor, and liver volumes as well as whole body fat percentage were evaluated by non-invasive in vivo micro-computed tomography (µCT), and livers were collected for subsequent analyses. Unexpectedly, the tumor load exploded in mTORLEC livers and knock-out mice showed improved glucose tolerance among other signs of major metabolic alterations. Detailed proteome analysis indicated extensive changes in arachidonic and bile acid metabolism in the liver. The simulation of metformin intervention via kinetic modeling predicted the existence of a therapeutic window, in which the drug selectively targets mTORLEC HCC tissue.
2023-11-15 | PXD039944 | Pride
Project description:Metformin is effective for prevention or treatment of various tumors. There are a lot of studies on the underlying mechanisms of metformin as respect to its anti-tumor action. We used microarrays to detail the global programme of gene expression underlying the anti-tumor effects of metformin on LoVo cells. Human derived LoVo cells were treated with metformin (10mM) for 8 and 24h, and the control and treated cells were harvested for RNA extraction and hybridization on Affymetrix microarrays.The samples were grouped as Met8h, Met24h, Con8h, and Con24h, respectively.
2015-03-31 | E-GEOD-67342 | biostudies-arrayexpress
Project description:Metformin is effective for prevention or treatment of various tumors. There are a lot of studies on the underlying mechanisms of metformin as respect to its anti-tumor action. We used microarrays to detail the global programme of gene expression underlying the anti-tumor effects of metformin on LoVo cells.
2015-03-31 | GSE67342 | GEO
Project description:Hepatocellular carcinoma (HCC), which accounts for 90% of all primary livers tumors, is the fourth most common cancer in the world. The development of HCC is a long-term and complex process, and uncovering the molecular mechanisms associated with HCC development is critical for the disease diagnosis, prevention, and treatment. Exploring these mechanisms using human HCC samples is desirable, but frequently impractical, with a number of limitations and shortcomings. The STAMTM (Stelic Institute & Co, Tokyo, Japan) mouse model of NASH-associated liver carcinogenesis is considered a useful and relevant model for investigating the molecular pathogenesis of NASH-derived HCC. This model resembles the human HCC development associated with progression from simple steatosis to NASH, fibrosis, and HCC. In the present study, by using high-throughput whole genome microarrays (SurePrint G3 Mouse Gene Expression v2, 8x60K; Agilent Technologies, Santa Clara, CA), we examined the transcriptomic profiles in the livers of STAMTM mice at different stages of liver carcinogenesis, including steatosis (6 week time interval), NASH (8 weeks), fibrotic stage (12 weeks), and in full-fledged HCC (20 weeks). The results of microarray analyses showed significant progressive changes in hepatic gene expression during the development of HCC. A total of 970, 1462, 2742, and 2857 of differentially expressed genes were identified in the livers at 6, 8, 12, and 20 weeks, respectively. Detailed analysis of these differentially expressed genes will benefit the understanding of the underlying mechanisms of non-alcoholic fatty liver disease-derived HCC. Transcriptomic profile in the liver of STAM mice at 6 weeks (steatosis; n=3), 8 weeks (steatohepatitis; n=3) 12 weeks (fibrosis; n=4) and 20 weeks (HCC-stage tumor tissue, n=4) weeks. Age-matched control samples were also analyzed.
2016-06-22 | E-GEOD-83596 | biostudies-arrayexpress
Project description:Reduced cancer incidence has been reported among type II diabetics treated with metformin. Metformin exhibits anti-proliferative and anti-neoplastic effects associated with inhibition of mTORC1, but the mechanisms are poorly understood. We provide the first genome-wide analysis of translational targets of canonical mTOR inhibitors (rapamycin and PP242) and metformin, revealing that metformin controls gene expression at the level of mRNA translation to an extent comparable to that of canonical mTOR inhibitors. Importantly, metformin's anti-proliferative activity can be explained by selective translational suppression of mRNAs encoding cell cycle regulators via the mTORC1/4E-BP pathway. Thus, metformin selectively inhibits mRNA translation of encoded proteins that promote neoplastic proliferation, motivating further studies of this compound and related biguanides in cancer prevention and treatment. MCF7 cells were treated with rapamycin, metformin or PP242 at concentrations that inhibited proliferation to 50% of control. Both cytoplasmic and polysome-associated mRNA was extracted from treatments and a vehicle treated control and probed with microarrays.
2012-05-20 | E-GEOD-36847 | biostudies-arrayexpress
Project description:<p>Despite the growing incidence of hepatocellular carcinoma (HCC) due to increased hepatitis C virus infection and non-alcoholic steatohepatitis in Western populations, the genetic determinants of this cancer have yet to be established. A minority (15-20%) of HCC occurs in livers without cirrhosis or other chronic disease. Because the liver is functionally preserved in these patients and surgical resection of the tumor may be performed safely, and because of the scarcity of livers available for transplantation, non-cirrhotic patients undergo surgical resection for HCC treatment. These resected tumors present investigatory opportunities in two ways: First, they provide tumor specimen which have not been treated with chemotherapy and embolization. Second, the absence of cirrhosis may provide an unconfounded background from which to investigate the genetic tumorigenesis of HCC. In livers with cirrhosis, genetic instability is prevalent as assessed by assays for microsatellite instability, loss of heterozygosity and aberrant DNA methylation. In contrast, in livers without cirrhosis, the non-tumor tissue surrounding HCC have been found to have fewer genetic aberrations. It has been postulated that the pathologic process of cirrhosis may result in the accumulation of many "passenger"; as well as "driver" mutations, and that the examination of the HCC cancer genome may be facilitated in non-cirrhotic livers because of the absence of an accumulated background noise of mutations.</p>
| phs001106 | dbGaP
Project description:Chronic liver inflammation precedes the majority of hepatocellular carcinomas (HCC). Here, we explore the connection between chronic inflammation and DNA methylation in the liver at the late precancerous stages of HCC development in Mdr2/Abcb4-knockout (Mdr2-KO) mice, a model of inflammation-mediated HCC. Using methylated DNA immunoprecipitation (MeDIP) followed by hybridization with Agilent CpG Islands (CGIs) microarrays we found specific CGIs in 76 genes which were hypermethylated in the Mdr2-KO liver compared to age-matched controls. Methylation of thirty among these genes was highly specific to the studied HCC model. We revealed that in most tested cases, the observed hypermethylation resulted from an age-dependent decrease of methylation of the specific CGIs in control livers with no decrease in mutant mice. Chronic inflammation did not change global levels of DNA methylation in Mdr2-KO liver, but caused a 2-fold decrease of the global 5-hydroxymethylcytosine level in mutants compared to controls. This decrease could result from a less efficient age-dependent demethylation of specific CpG sites in the liver of Mdr2-KO mutants, as described above. Expression of some tested hypermethylated genes was increased in Mdr2-KO livers compared to controls (28%), others were either similarly expressed (44%), or not expressed in the liver (28%). Liver cell fractionation revealed, that the relative hypermethylation of specific CGIs in Mdr2-KO compared to control livers affected either hepatocyte, or non-hepatocyte, or both fractions. There was only episodic correlation between changes of gene methylation and expression in cell fractions. Conclusion: Chronic liver inflammation causes hypermethylation of specific CGIs, which may affect both hepatocytes and non-hepatocyte liver cells. These changes may serve as markers of an increased regenerative activity and of a precancerous microenvironment in the chronically inflamed liver. Two-condition experiment, Mdr2-KO vs Mdr2-/+ liver tissue from 12m-old male FVB strain mice. Biological replicates: 3 control replicates, 3 knockout replicates.
2015-03-01 | E-GEOD-64097 | biostudies-arrayexpress