Non-coding NOTCH1 mutations in chronic lymphocytic leukemia; their clinical impact in the UK CLL4 trial.
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ABSTRACT:
SUBMITTER: Larrayoz M
PROVIDER: S-EPMC5289571 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Chronic lymphocytic leukemia (CLL) is the most frequent leukemia type in which the genetic alterations influencing the clinico-biological course are not entirely understood. CLL has a heterogeneous course, with some patients showing an indolent course and others experiencing an aggressive course. Whole-genome sequencing and whole-exome sequencing studies identified recurrently mutated genes in CLL and profiled its clonal evolution patterns. However, more recent whole-genome sequencing studies also identified variants in non-coding sequences of the CLL genome, revealing important lesions outside the protein-coding regions. Here we describe the most representative non-coding lesion of the CLL genome, including lesions in the 3'-UTR region of NOTCH1 which result in the truncation of the NOTCH1 protein PEST domain, and non-coding mutations in an enhancer region on chromosome 9p13 which result in reduced expression of the PAX5 transcription factor. In addition, we describe the role of microRNA in CLL, in particular the miR15a/miR16-1 microRNA recurrently affected by deletions of chromosome 13q14. Together, new findings in non-coding genome genetic lesions provide a more complete portrait of the genomic landscape of CLL with clinical implications.
| S-EPMC6322188 | biostudies-other
Project description:BACKGROUND: NOTCH1 PEST domain mutations in chronic lymphocytic leukemia have recently been shown to be of prognostic relevance. Both NOTCH1 and NOTCH2 are constitutively activated in B-cell CLL but not expressed in normal B cells and may be involved in survival and resistance to apoptosis in CLL. We screened for mutations in different parts of both NOTCH1 and NOTCH2 genes and related the changes to survival and other known risk factors. METHODS: In a cohort of 209 CLL patients, we used single strand conformation analysis to determine which of the samples carrying the NOTCH mutations and direct dideoxy sequencing was used to determine the exact nucleotide changes. Kaplan-Meier curves and log rank test were used to determine overall survival for NOTCH1 mutated cases and Cox regression analysis was used to calculate hazardous ratios. RESULTS: In the present study, we found NOTCH1 PEST domain mutations in 6.7% of the cases. A shorter overall survival was found in patients with NOTCH1 mutations compared to wildtype (p = 0.049). Further, we also examined the extracellular and the heterodimerisation domains of the NOTCH1 gene and the PEST domain and heterodimerisation domain of the NOTCH2 gene, but no mutations were found in these regions. NOTCH1 mutations were most commonly observed in patients with unmutated IGHV gene (10/14), and associated with a more aggressive disease course. In addition, NOTCH1 mutations were almost mutually exclusive with TP53 mutations. In the combined group of NOTCH1 (6.7%) or TP53 (6.2%) mutations, a significant difference in overall survival compared to the wildtype NOTCH1 and TP53 was found (p = 0.002). CONCLUSIONS: Both NOTCH1 and TP53 mutations seem to be independent predictive markers for worse outcome in CLL-patients and this study emphasizes the contention that NOTCH1 mutations is a novel risk marker.
| S-EPMC3679784 | biostudies-literature
Project description:The Notch signaling pathway plays a fundamental role for the terminal differentiation of multiple cell types, including B and T lymphocytes. The Notch receptors are transmembrane proteins that, upon ligand engagement, undergo multiple processing steps that ultimately release their intracytoplasmic portion. The activated protein ultimately operates as a nuclear transcriptional co-factor, whose stability is finely regulated. The Notch pathway has gained growing attention in chronic lymphocytic leukemia (CLL) because of the high rate of somatic mutations of the NOTCH1 gene. In CLL, NOTCH1 mutations represent a validated prognostic marker and a potential predictive marker for anti-CD20-based therapies, as pathological alterations of the Notch pathway can provide significant growth and survival advantage to neoplastic clone. However, beside NOTCH1 mutation, other events have been demonstrated to perturb the Notch pathway, namely somatic mutations of upstream, or even apparently unrelated, proteins such as FBXW7, MED12, SPEN, SF3B1, as well as physiological signals from other pathways such as the B-cell receptor. Here we review these mechanisms of activation of the NOTCH1 pathway in the context of CLL; the resulting picture highlights how multiple different mechanisms, that might occur under specific genomic, phenotypic and microenvironmental contexts, ultimately result in the same search for proliferative and survival advantages (through activation of MYC), as well as immune escape and therapy evasion (from anti-CD20 biological therapies). Understanding the preferential strategies through which CLL cells hijack NOTCH1 signaling may present important clues for designing targeted treatment strategies for the management of CLL.
| S-EPMC9221163 | biostudies-literature
Project description:Chronic lymphocytic leukemia (CLL) is an incurable B-cell neoplasm characterized by highly variable clinical outcomes. In recent years, genomic and molecular studies revealed a remarkable heterogeneity in CLL, which mirrored the clinical diversity of this disease. These studies profoundly enhanced our understanding of leukemia cell biology and led to the identification of new biomarkers with potential prognostic and therapeutic significance. Accumulating evidence indicates a key role of deregulated NOTCH1 signaling and NOTCH1 mutations in CLL. This review highlights recent discoveries that improve our understanding of the pathophysiological NOTCH1 signaling in CLL and the clinical impact of NOTCH1 mutations in retrospective and prospective trials. In addition, we discuss the rationale for a therapeutic strategy aiming at inhibiting NOTCH1 signaling in CLL, along with an overview on the currently available NOTCH1-directed approaches.
| S-EPMC6030253 | biostudies-literature
Project description:The pathogenesis of chronic lymphocytic leukemia (CLL), the most common leukemia in adults, is still largely unknown. The full spectrum of genetic lesions that are present in the CLL genome, and therefore the number and identity of dysregulated cellular pathways, have not been identified. By combining next-generation sequencing and copy number analysis, we show here that the typical CLL coding genome contains <20 clonally represented gene alterations/case, including predominantly nonsilent mutations, and fewer copy number aberrations. These analyses led to the discovery of several genes not previously known to be altered in CLL. Although most of these genes were affected at low frequency in an expanded CLL screening cohort, mutational activation of NOTCH1, observed in 8.3% of CLL at diagnosis, was detected at significantly higher frequency during disease progression toward Richter transformation (31.0%), as well as in chemorefractory CLL (20.8%). Consistent with the association of NOTCH1 mutations with clinically aggressive forms of the disease, NOTCH1 activation at CLL diagnosis emerged as an independent predictor of poor survival. These results provide initial data on the complexity of the CLL coding genome and identify a dysregulated pathway of diagnostic and therapeutic relevance.
| S-EPMC3135373 | biostudies-literature
Project description:Mutations in certain genes have been suggested to be associated with the pathogenesis of chronic lymphocytic leukemia (CLL), which is the most common leukemia in adults. In a case-control study, 100 patients with CLL and 105 healthy individuals were investigated for Notch homolog 1, translocation-associated (Drosophila) (NOTCH1) c.7544-7545delCT, recombinant splicing factor 3B subunit 1 (SF3B1) c.2098A>G, mouse double minute 2 homolog (MDM2) 40-bp insertion/deletion and myeloid differentiation primary response 88 (MYD88) L265P mutations by using allele specific-polymerase chain reaction (AS-PCR), a designed AS-PCR, PCR and PCR-restriction fragment length polymorphism methods, respectively. The presence of NOTCH1 and SF3B1 mutations were confirmed by genomic DNA sequencing. The NOTCH1 mutation was detected in 10% of patients and not detected in the control group. A higher frequency of NOTCH1 mutation was detected in patients with stage III CLL (62.5%) compared with stages 0-II CLL (37.5%) (odds ratio, 4.69-fold; 95% confidence interval, 1.0-21.9; P=0.049). The SF3B1 mutation was observed in 12% of the patients compared with 1.9% of the controls (P=0.012). The presence of MDM2 polymorphism was not associated with the risk or the stage of the disease. In addition, the MYD88 L265P mutation was not detected in the patients or the controls. The current study established the frequency of NOTCH1, SF3B1, MDM2 and MYD88 mutations in patients with CLL from the Kurdish population of Western Iran. In summary, a high frequency of NOTCH1 and SF3B1 mutations were identified in patients with CLL compared with healthy individuals, and the NOTCH1 mutation was associated with a high stage of the disease.
| S-EPMC6425375 | biostudies-literature
Project description:Genomic studies have revealed the complex clonal heterogeneity of chronic lymphocytic leukemia (CLL). The acquisition and selection of genomic aberrations may be critical to understanding the progression of this disease. In this study, we have extensively characterized the mutational status of TP53, SF3B1, BIRC3, NOTCH1, and ATM in 406 untreated CLL cases by ultra-deep next-generation sequencing, which detected subclonal mutations down to 0.3% allele frequency. Clonal dynamics were examined in longitudinal samples of 48 CLL patients. We identified a high proportion of subclonal mutations, isolated or associated with clonal aberrations. TP53 mutations were present in 10.6% of patients (6.4% clonal, 4.2% subclonal), ATM mutations in 11.1% (7.8% clonal, 1.3% subclonal, 2% germ line mutations considered pathogenic), SF3B1 mutations in 12.6% (7.4% clonal, 5.2% subclonal), NOTCH1 mutations in 21.8% (14.2% clonal, 7.6% subclonal), and BIRC3 mutations in 4.2% (2% clonal, 2.2% subclonal). ATM mutations, clonal SF3B1, and both clonal and subclonal NOTCH1 mutations predicted for shorter time to first treatment irrespective of the immunoglobulin heavy-chain variable-region gene (IGHV) mutational status. Clonal and subclonal TP53 and clonal NOTCH1 mutations predicted for shorter overall survival together with the IGHV mutational status. Clonal evolution in longitudinal samples mainly occurred in cases with mutations in the initial samples and was observed not only after chemotherapy but also in untreated patients. These findings suggest that the characterization of the subclonal architecture and its dynamics in the evolution of the disease may be relevant for the management of CLL patients.
| S-EPMC4912011 | biostudies-literature
Project description:The discovery of non-coding RNAs (ncRNAs) and their role in tumor onset and progression has revolutionized the way scientists and clinicians study cancers. This discovery opened new layers of complexity in understanding the fine-tuned regulation of cellular processes leading to cancer. NcRNAs represent a heterogeneous group of transcripts, ranging from a few base pairs to several kilobases, that are able to regulate gene networks and intracellular pathways by interacting with DNA, transcripts or proteins. Deregulation of ncRNAs impinge on several cellular responses and can play a major role in each single hallmark of cancer. This review will focus on the most important short and long non-coding RNAs in chronic lymphocytic leukemia (CLL), highlighting their implications as potential biomarkers and therapeutic targets as they relate to the well-established hallmarks of cancer. The key molecular events in the onset of CLL will be contextualized, taking into account the role of the "dark matter" of the genome.
| S-EPMC7554994 | biostudies-literature
Project description:Chronic lymphocytic leukemia (CLL) is highly heterogeneous, with extremely variable clinical course. The clinical heterogeneity of CLL reflects differences in the biology of the disease, including chromosomal alterations, specific immunophenotypic patterns and serum markers. The application of next-generation sequencing techniques has demonstrated the high genetic and epigenetic heterogeneity in CLL. The novel mutations could be pharmacologically targeted for individualized approach in some of the CLL patients. Potential neurogenic locus notch homolog protein 1 (NOTCH1) signalling targeting mechanisms in CLL include secretase inhibitors and specific antibodies to block NOTCH ligand/receptor interactions. In vitro studies characterizing the effect of the splicing inhibitors resulted in increased apoptosis of CLL cells regardless of splicing factor 3B subunit 1 (SF3B1) status. Several therapeutic strategies have been also proposed to directly or indirectly inhibit the toll-like receptor/myeloid differentiation primary response gene 88 (TLR/MyD88) pathway. Another potential approach is targeting nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and inhibition of this prosurvival pathway. Newly discovered mutations and their signalling pathways play key roles in the course of the disease. This opens new opportunities in the management and treatment of CLL.
| S-EPMC8396993 | biostudies-literature
Project description:Background and aimChronic lymphocytic leukemia (CLL) is a monoclonal malignancy of B lymphocytes. Since common mutations in NOTCH1 and SF3B1, along with other possible chromosomal alterations, change disease severity and survival of patients with CLL, we aimed to evaluate the correlation of common mutations in NOTCH1 and SF3B1 as the poor prognostic markers with chromosomal abnormalities and clinical hematology.MethodThis retrospective study was performed on the peripheral blood of 51 patients diagnosed before chemotherapy with CLL. G-banding karyotype and FISH were performed. For NOTCH1, exon 34 and for SF3B1, exons 14,15,16 were assessed using Sanger sequencing.ResultsThe mutation frequency of NOTCH1 and SF3B1 with the pathogenic clinical status was 6:51 (11.76%), and variants obtained from both genes were 9:51 (17.64%). The frequency of SF3B1 mutation (K666E) was higher than in previous studies (p-value <.05). There was a significant correlation between NOTCH1 mutations and del17p13 (p-value = .068), also SF3B1 mutations with del11q22 (p-value = .095) and del13q14 (p-value = .066). Up to 90% of the specific stimuli used for the G-banding karyotype successfully identified the malignant clone. There was a significant relationship between the cluster of differentiation 38 (CD38) expression level and NOTCH1 mutations (p-value = .019) and a significant correlation between Binet classification and the SF3B1 (p-value = .096).ConclusionThe correlation of NOTCH1 and SF3B1 mutations with chromosomal abnormalities and CD38 expression may reveal the overall patient's survival rate. The mutations may be effective in the clonal expansion and progression of CLL, particularly in the diagnosis stage, as well as the control and management of the treatment.
| S-EPMC10026310 | biostudies-literature