Project description:Neuroendocrine neoplasms are a rare and heterogeneous group of neoplasms. Small sized (≤ 2 cm) pancreatic neuroendocrine tumors (pNETs) are of particular interest, as they are often associated with aggressive behavior, with no specific prognostic or progression markers. This article describes a clinical case characterized by a progressive growth of non-functional pNET requiring surgical treatment, in a patient with a germline FANCD2 mutation, previously not reported in pNETs.
Project description:Fanconi Anemia (FA) is a rare genetic disorder characterized by an increased susceptibility to squamous cell cancers. Fifteen FA genes are known, and the encoded proteins cooperate in a common DNA repair pathway. A critical step is the monoubiquitination of the FANCD2 protein, and cells from most FA patients are deficient in this step. How monoubiquitinated FANCD2 suppresses squamous cell cancers is unknown. Here we show that Fancd2-deficient mice are prone to Ras oncogene-driven skin carcinogenesis, while Usp1-deficient mice, expressing elevated cellular levels of Fancd2-Ub, are resistant to skin tumors. Moreover, Fancd2-Ub activates the transcription of the tumor suppressor TAp63, thereby promoting cellular senescence and blocking skin tumorigenesis. For FA patients, the reduction of FANCD2-Ub and TAp63 protein levels may account for their susceptibility to squamous cell neoplasia. Taken together, Usp1 inhibition may be a useful strategy for upregulating TAp63 and preventing or treating squamous cell cancers in the general non-FA population. Examination of FANCD2 binding after UV treatment in 293T cells
Project description:Glioneuronal tumor (GN) is one type of biphasic central nervous system (CNS) tumor that exhibits both glial and neuronal immunohistological characteristics. We report a case of glioneuronal tumor (GN) with a discovery of novel gene fusion of CLIP2-MET resulting from aberrant chromosome 7 abnormalities. The tumor exhibited typical characteristics on histological examinations. We executed an elaborate genomic study on this case including whole-exome sequencing and RNA sequencing. Genomic analysis of the tumor revealed aberrations in chromosomes 1 and 7 and a CLIP2-MET fusion. Further analysis of the upregulated genes revealed substantial connections with MAPK pathway activation. We concluded that the chromosome 7 abnormalities prompted CLIP2-MET gene fusion which successively leads to MAPK pathway activation. We deliberated that MAPK pathway activation is responsible for the oncogenesis of GN based on our case and other previously reported ones.
Project description:To characterize pancreatic neuroendocrine tumor at protein level, we performed mass spectromery-based proteome analysis using clinical FFPE tissue samples.
Project description:Fanconi Anemia (FA) is a rare genetic disorder characterized by an increased susceptibility to squamous cell cancers. Fifteen FA genes are known, and the encoded proteins cooperate in a common DNA repair pathway. A critical step is the monoubiquitination of the FANCD2 protein, and cells from most FA patients are deficient in this step. How monoubiquitinated FANCD2 suppresses squamous cell cancers is unknown. Here we show that Fancd2-deficient mice are prone to Ras oncogene-driven skin carcinogenesis, while Usp1-deficient mice, expressing elevated cellular levels of Fancd2-Ub, are resistant to skin tumors. Moreover, Fancd2-Ub activates the transcription of the tumor suppressor TAp63, thereby promoting cellular senescence and blocking skin tumorigenesis. For FA patients, the reduction of FANCD2-Ub and TAp63 protein levels may account for their susceptibility to squamous cell neoplasia. Taken together, Usp1 inhibition may be a useful strategy for upregulating TAp63 and preventing or treating squamous cell cancers in the general non-FA population.
Project description:Oncogene-induced replication stress constitutes an early obstacle for pre-cancerous cells to overcome to progress towards malignancy. Fanconi anaemia signalling represents a major genomic maintenance pathway that is activated in response to replication stress, impinging on stalled replication fork stability and recovery. We report that upon replication stress, phosphorylation of the FANCD2 N-terminus by CHK1 triggers FBXL12-dependent proteasomal degradation of FANCD2, facilitating clearance of FANCD2 at stalled replication forks and promoting replication recovery. Monoubiquitination of FANCD2 at K561 by the Fanconi anaemia core complex regulates clamping of the FANCD2-FANCI heterodimer onto DNA. To investigate if K561-monoubiquitination influences FANCD2 phosphorylation and/or polyubiquitination by FBXL12, we performed MS-based proteomics using HEK293 cells co-transfected with the monoubiquitin-deficient FANCD2 mutant (K561R) and FANCI, or a CHK1 phosphorylation-deficient FANCD2-AA (S8A/S10A) mutant as control. To induce rapid activation of CHK1, we inhibited WEE1 kinase using AZD1775, immunoprecipitated FANCD2 from chromatin extracts and performed MS analysis. The MS data revealed several phosphorylated N-terminal peptides in the K561R-FANCD2 sample, including S8, S10 and also S15 demonstrating that K561R is phosphorylated in response to replication stress induced by AZD1775.