Identification and Functional Analysis of a Novel CTNNB1 Mutation in Pediatric Medulloblastoma.
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ABSTRACT:
SUBMITTER: Alana L
PROVIDER: S-EPMC8773623 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundTo explore the molecular genetic cause of a four-generation autosomal dominant congenital cataract family in China.MethodsTargeted region sequencing was performed to screen for the potential mutation, and Sanger sequencing was used to confirm the mutation. The homology model was constructed to identify the protein structural change, PolyPhen-2 and Provean were used to predict the mutation impact. Functional and cellular analysis of the wild and mutant GJA8 were performed in DF-1 cells by western blotting, dye uptake assay, immunofluorescence, Annexin V-FITC staining.ResultsA novel heterozygous mutation (c.205G > A; p.Ala69Thr) was identified within GJA8, which cosegregated with congenital cataract phenotype in this family. Bioinformatics analysis showed the mutation was located in a highly conserved region, and the mutation was predicted to be pathogenic. Function analysis indicated that the mutation inhibited GJA8 hemichannel activity, reduced cell tolerance to oxidative stress, changed the protein distribution pattern and inhibited the cell growth.ConclusionsWe have identified a novel missense mutation in GJA8 (c.205G > A, p.Ala69Thr) in a four-generation Chinese family and our results will further broaden the gene mutation spectrum of GJA8.
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Project description:BackgroundCraniopharyngioma (CP) is rare histologically benign but clinically challenging tumor because of its intimate relationship with the critical structure in the central brain. CP can be divided into two major histologic subtypes: adamantinomatous-type CP (ACP) and papillary-type CP (PCP). Although some genetic aberrations for both categories have been revealed in previous studies, the complete spectrum of genetic changes of this tumor remains unknown.MethodsIn this study, we conducted whole genome sequencing (WGS) on twenty-six CPs including 16 ACPs and 10 PCPs together with their matched blood samples. Somatic variants (SNVs, InDels, SVs and CNVs) were identified and mutational signatures were characterized for each patient. We investigated the impact of a novel CTNNB1 mutant on its protein stability, ubiquitination and Wnt pathway activity. Cell proliferation ability of the CTNNB1 mutant in ACP primary cells was additionally analyzed by CCK8 and colony formation assays.ResultsWe found that CPs had showed less complexity with fewer somatic mutations compared with malignant tumors. Moreover, mutations in CTNNB1 (68.75% of ACP) and BRAF V600E (70.00% of PCP) are mutually exclusive in ACP and PCP, consolidating that the driving roles of these two genes in ACP and PCP, respectively. A novel mutation in the exon 3 of CTNNB1 which compromised both a transversion and in-frame deletion was identified in ACP. This mutation was experimentally validated to confer β-catenin increased stability by inhibiting its ubiquitination, thus activating Wnt-signaling pathway and promoting cell proliferation.ConclusionsWhole genome landscape for CP was revealed by WGS analysis, and a novel mutation in the exon 3 of CTNNB1 was identified. This novel mutation activates Wnt-signaling pathway through increasing the stability of β-catenin. Our findings provided us with more comprehensive insight into the spectrum of genetic alterations in CP.
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Project description:The Wnt/β-Catenin signaling pathway is one of the most frequently altered pathways in adrenocortical carcinomas (ACCs). The aim of this study was to investigate the status of Wnt/β-Catenin signaling pathway by analyzing the expression level of β-Catenin and the mutational status of APC, AXIN2, CTNNB1, and ZNRF3 in ACCs. Mutations in APC, CTNNB1, ZNRF3 and homozygous deletions in ZNRF3 were observed in 3.8% (2/52), 11.5% (6/52), 1.9% (1/52) and 17.3% (9/52) of the cohort respectively. Novel interstitial deletions in CTNNB1 spanning intron 1 to exon 3/intron 3 were also found in 7.7% (4/52) of the tumours. All the observed alterations were mutually exclusive. Nuclear accumulation of β-Catenin, increased expression of Cyclin D1 and significantly higher expression of AXIN2 (p = 0.0039), ZNRF3 (p = 0.0032) and LEF1(p = 0.0090) observed in the tumours harbouring the deletion in comparison to tumours without CTNNB1 mutation demonstrates that the truncated β-Catenin is functionally active and erroneously activates the downstream targets. Significantly lower overall survival rate in patients with tumours harbouring alterations in APC/CTNNB1/ZNRF3 in comparison to those without mutation was observed. In conclusion, the discovery of novel large deletions in addition to the point mutations in CTNNB1 infers that activation of Wnt/β-Catenin pathway via alterations in CTNNB1 occurs frequently in ACCs. We also confirm that alterations in Wnt/β-Catenin signaling pathway members have a negative effect on overall survival of patients.
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Project description:Mouse models of medulloblastoma have proven to be instrumental in understanding disease mechanisms, particularly the role of epigenetic and molecular drivers, and establishing appropriate preclinical pipelines. To date, our research community has developed murine models for all four groups of medulloblastoma, each of which will be critical for the identification and development of new therapeutic approaches. Approaches to modeling medulloblastoma range from genetic engineering with CRISPR/Cas9 or in utero electroporation, to orthotopic and patient-derived orthotopic xenograft systems. Each approach or model presents unique advantages that have ultimately contributed to an appreciation of medulloblastoma heterogeneity and the clinical obstacles that exist for this patient population.
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Project description:The impact of protein-coding genes on cancer onset and progression is a well-established paradigm in molecular oncology. Nevertheless, unveiling the contribution of the noncoding genes-including long noncoding RNAs (lncRNAs)-to tumorigenesis represents a great challenge for personalized medicine, since they (i) constitute the majority of the human genome, (ii) are essential and flexible regulators of gene expression and (iii) present all types of genomic alterations described for protein-coding genes. LncRNAs have been increasingly associated with cancer, their highly tissue- and cancer type-specific expression making them attractive candidates as both biomarkers and therapeutic targets. Medulloblastoma is one of the most common malignant pediatric brain tumors. Group 3 is the most aggressive subgroup, showing the highest rate of metastasis at diagnosis. Transcriptomics and reverse genetics approaches were combined to identify lncRNAs implicated in Group 3 Medulloblastoma biology. Here we present the first collection of lncRNAs dependent on the activity of the MYC oncogene, the major driver gene of Group 3 Medulloblastoma. We assessed the expression profile of selected lncRNAs in Group 3 primary tumors and functionally characterized these species. Overall, our data demonstrate the direct involvement of three lncRNAs in Medulloblastoma cancer cell phenotypes.
| S-EPMC8345409 | biostudies-literature
Project description:BackgroundMedulloblastoma is an aggressive brain tumor mostly found in children, few studies on pathogenic germline mutations predisposing this disease was reported.Case presentationWe present an 11-year-old male with medulloblastoma, who harbors a de novo PHOX2B germline mutation as detected by whole exome sequencing (WES). Family history was negative. Sanger sequencing confirmed this mutation in peripheral blood, hair bulbs, urine and saliva. Identification of novel germline mutations is beneficial for childhood cancer screening.ConclusionsThis case revealed a de novo PHOX2B germline mutation as a potential cause of medulloblastoma in a child and suggests familial germline variant screening is useful when an affected family is considering having a second child.
| S-EPMC7816394 | biostudies-literature
Project description:The CTNNB1 gene encode the β-catenin protein which is a core unit of the cadherin/catenin multiprotein complex. The loss-of-function mutation of the CTNNB1 gene recently has been confirmed as a cause of intellectual disability. Previous studies have found that patients with CTNNB1 gene mutation may have other clinical manifestation such as microcephaly, abnormal facial features, motor and language delays, and mild visual defects. Here, we reported a 27-year-old Chinese pregnant woman with a severe intellectual disability and serious visual defects who was detected with a novel splice mutation (c.734+1G>A) in CTNNB1 gene by whole-exome sequencing and confirmed by Sanger sequencing. Further investigation showed that the variant was inherited from her mother with similar phenotypes. This report not only helps to expand the mutant spectrum of the CTNNB1 gene but also prompts a new insight into genetic diagnosis in patients with both serious intellectual disability and visual defects.
| S-EPMC6647480 | biostudies-literature
Project description:Medulloblastoma is the most common malignant brain tumor of the central nervous system among children. Medulloblastoma is an embryonal tumor, of which little is known about the pathogenesis. Several efforts have been made to understand the molecular aspects of its tumorigenic pathways; however, these are poorly understood. microRNA (miRNA), a type of non?coding short RNA, has been proven to be associated with a number of physiological processes and pathological processes of serious diseases, including brain tumors. Differentially expressed miRNAs serve an important role in numerous types of malignancy. The present study aims to define a differentially expressed set of miRNAs in medulloblastoma tumor tissue, compared with normal samples, to improve the understanding of the tumorigenesis. It was identified that 22 miRNAs were upregulated and 26 miRNAs were downregulated in the tumor tissue compared with the normal group. However, when the medulloblastoma tissue was compared with normal cerebellum tissue, 9 miRNAs were identified to be up or downregulated in the tumor samples. The differentially expressed miRNAs in the tumor tissue were identified in order to clarify the networks and pathways of tumorigenesis using Ingenuity Pathway Analysis. Subsequently, key regulatory genes associated with the development of medulloblastoma were identified, including tumor protein p53, insulin like growth factor 1 receptor, argonaute 2, mitogen?activated protein kinases 1 and 3, sirtuin 1 and Y box binding protein 1.
| S-EPMC5436210 | biostudies-literature
Project description:IntroductionLung adenocarcinoma with CTNNB1 mutation is relatively uncommon, and its clinicopathologic characteristics, disease course, and prognosis have not been well-studied.MethodsA total of 564 lung adenocarcinoma patients were enrolled in this study. The relationship between CTTNB1 mutational status and clinicopathologic parameters, the rates of relapse-free survival (RFS) and overall survival (OS), and the mutational status of other genes commonly mutated in lung adenocarcinoma were analyzed.ResultsOf 564 lung adenocarcinoma patients, 30 (5.3%) harbored CTNNB1 mutations. Univariate analyses revealed that gender, smoking history, pleural invasion, and histological subtype were all significant predictors of RFS and OS. Pleural invasion and histological subtype remained significant predictors of RFS and OS in a multivariate analysis. There were no significant differences in RFS (p = 0.504) or OS (p = 0.054) between lung adenocarcinoma patients with CTNNB1 mutation and those without CTNNB1 mutation. However, patients with CTNNB1 mutation tended to have a worse OS.ConclusionsFemale patients and nonsmokers are likely to harbor CTNNB1 mutation and primary lung adenocarcinoma with mutated CTNNB1 has a poor prognosis.
| S-EPMC7026668 | biostudies-literature
Project description:Medulloblastoma is the most common malignant brain tumor affecting children. These tumors are high grade with propensity to metastasize within the central nervous system and, less frequently, outside the neuraxis. Recent advancements in molecular subgrouping of medulloblastoma refine diagnosis and improve counseling in regards to overall prognosis. Both are predicated on the molecular drivers of each subgroup-WNT-activated, SHH-activated, group 3, and group 4. The traditional therapeutic mainstay for medulloblastoma includes a multimodal approach with surgery, radiation, and multiagent chemotherapy. As we discover more about the molecular basis of medulloblastoma, efforts to adjust treatment approaches based on molecular risk stratification are under active investigation. Certainly, the known neurological, developmental, endocrine, and psychosocial injury related to medulloblastoma and its associated therapies motivate ongoing research towards improving treatment for this life-threatening tumor while at the same time minimizing long-term side effects.
| S-EPMC5909805 | biostudies-literature