Dataset Information

SNP55, a new functional polymorphism of MDM2-P2 promoter, contributes to allele-specific expression of MDM2 in endometrial cancers.

ABSTRACT: The functional single nucleotide polymorphism (SNP) in the MDM2 promoter region, SNP309, is known to be associated with various diseases, particularly cancer. Although many studies have been performed to demonstrate the mechanism of allele-specific expression (ASE) on SNP309, they have only utilized in vitro techniques. It is unknown whether ASE of MDM2 is ascribed solely to SNP309, in vivo.We attempted to evaluate ASE of MDM2 in vivo using post-labeling followed by automated capillary electrophoresis under single-strand conformation polymorphism conditions. For measuring a quantitative difference, we utilized the SNPs on the exons of MDM2 as markers, the status of which was heterozygous in a large population. To address the cause of ASE beyond 20%, we confirmed sequences of both MDM2-3'UTR and promoter regions. We assessed the SNP which might be the cause of ASE using biomolecular interaction analysis and luciferase assay.ASE beyond 20% was detected in endometrial cancers, but not in cancer-free endometria samples only when an SNP rs1690916 was used as a marker. We suspected that this ASE in endometrial cancer was caused by the sequence heterogeneity in the MDM2-P2 promoter, and found a new functional polymorphism, which we labelled SNP55. There was no difference between cancer-free endometria and endometrial cancer samples neither for SNP55 genotype frequencies nor allele frequencies, and so, SNP55 alone does not affect endometrial cancer risk. The SNP55 status affected the DNA binding affinity of transcription factor Sp1 and nuclear factor kappa-B (NF?B). Transcriptional activity of the P2 promoter containing SNP55C was suppressed by NF?B p50 homodimers, but that of SNP55T was not. Only ASE-positive endometrial cancer samples displayed nuclear localization of NF?B p50.Our findings suggest that both the SNP55 status and the NF?B p50 activity are important in the transcriptional regulation of MDM2 in endometrial cancers.

SUBMITTER: Okamoto K

PROVIDER: S-EPMC4593204 | biostudies-literature | 2015 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

SNP55, a new functional polymorphism of MDM2-P2 promoter, contributes to allele-specific expression of MDM2 in endometrial cancers.

Okamoto Kanako K Tsunematsu Ryosuke R Tahira Tomoko T Sonoda Kenzo K Asanoma Kazuo K Yagi Hiroshi H Yoneda Tomoko T Hayashi Kenshi K Wake Norio N Kato Kiyoko K

BMC medical genetics 20150821

<h4>Background</h4>The functional single nucleotide polymorphism (SNP) in the MDM2 promoter region, SNP309, is known to be associated with various diseases, particularly cancer. Although many studies have been performed to demonstrate the mechanism of allele-specific expression (ASE) on SNP309, they have only utilized in vitro techniques. It is unknown whether ASE of MDM2 is ascribed solely to SNP309, in vivo.<h4>Methods</h4>We attempted to evaluate ASE of MDM2 in vivo using post-labeling follow ...[more]

PMID: 26293665

Similar Datasets

Project description:Background and Purpose- The E3 ubiquitin ligase MDM2 (murine double minute 2) is the main negative regulator of the p53 protein-a key player in neuronal apoptosis after ischemia. A functional single-nucleotide polymorphism in the human MDM2 gene promoter (rs2279744) regulates MDM2 protein expression. We investigated whether the MDM2 SNP309, by controlling p53-mediated apoptosis, determines functional outcome after stroke. Methods- Primary cortical neurons were subjected to oxygen and glucose deprivation. Mice were subjected to ischemic (transient middle cerebral artery occlusion) or hemorrhagic (collagenase injection) stroke models. Protein and mRNA levels of MDM2 and p53 were measured in both neuronal and brain extracts. The interaction of MDM2 with p53 was disrupted by neuronal treatment with nutlin-3a. siRNA was used to knockdown MDM2 expression. We analyzed the link between the MDM2 SNP309 and functional outcome, measured by the modified Rankin Scale scores, in 2 independent hospital-based stroke cohorts: ischemic stroke cohort (408 patients) and intracerebral hemorrhage cohort (128 patients). Results- Experimental stroke and oxygen and glucose deprivation induced the expression of MDM2 in the brain and neurons, respectively. Moreover, oxygen and glucose deprivation promoted MDM2 binding with p53 in neurons. Disruption of the MDM2-p53 interaction with nutlin-3a, or MDM2 knockdown by siRNA, triggered p53 accumulation, which increased neuronal susceptibility to oxygen and glucose deprivation-induced apoptosis. Finally, we showed that patients harboring the G allele in the MDM2 promoter had higher MDM2 protein levels and showed better functional outcome after stroke than those harboring the T/T genotype. The T/T genotype was also associated with large infarct volume in ischemic stroke and increased lesion volume in patients with intracerebral hemorrhage. Conclusions- Our results reveal a novel role for the MDM2-p53 interaction in neuronal apoptosis after ischemia and show that the MDM2 SNP309 determines the functional outcome of patients after stroke.

Dataset Information

SNP55, a new functional polymorphism of MDM2-P2 promoter, contributes to allele-specific expression of MDM2 in endometrial cancers.

Publications

SNP55, a new functional polymorphism of MDM2-P2 promoter, contributes to allele-specific expression of MDM2 in endometrial cancers.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets