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Results for “SF3B1”

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PubMed2025

Precursor RNA structural patterns at SF3B1 mutation sensitive cryptic 3' splice sites.

SF3B1 is a core component of the spliceosome involved in branch point recognition and 3' splice site selection. The SF3B1 K700E mutation (lysine to glutamic acid) is common in myelodysplastic syndrome and other blood disorders. SF3B1 K700E mutants utilize novel cryptic 3' splice sites; however, the properties distinguishing SF3B1-sensitive splice junctions from other alternatively spliced junctions are unknown. We identify a subset of 192 cryptic 3' splice junctions with significantly altered use in SF3B1 K700E cells, termed SF3B1-sensitive cryptic 3' splice sites, and 2800 cryptic 3' splice sites used in SF3B1 wild-type, termed SF3B1-resistant. We find that SF3B1-sensitive cryptic 3' splice sites are embedded in extended polypyrimidine tracts. Furthermore, canonical splice sites paired to SF3B1-sensitive cryptic 3' splice sites are significantly weaker than canonical 3' splice sites paired to SF3B1-resistant cryptic 3' splice sites. We test whether SF3B1-sensitive splice sites are structurally different from SF3B1-resistant 3' splice sites using chemical probing. We develop experimental RNA structure data for 83 SF3B1-sensitive junctions and 39 SF3B1-resistant junctions. We find that the pattern of structural accessibility at the NAG splicing motif in cryptic and canonical 3' splice sites is similar. However, the magnitude of accessibility differences is less in paired SF3B1-sensitive splice sites than in paired SF3B1-mutant splice sites. Additionally, SF3B1-sensitive splice junctions are more flexible than SF3B1-resistant junctions. Our results suggest that SF3B1-sensitive splice junctions have unique structure and sequence properties, containing poorly differentiated, weak splice sites that lead to altered 3' splice site recognition in the presence of SF3B1 mutation.

RNA Splicing Factors↗

PubMed2026

Oncogenic SF3B1 mutations alter the splicing of mRNA noncoding regions to induce a novel therapeutic vulnerability.

Oncogenic mutations of SF3B1 are common in myeloid cancers, chronic lymphocytic leukemia (CLL), and select solid tumors. Their mechanistic basis for promoting oncogenesis has been investigated in detail, with the stereotyped missplicing of messenger RNA (mRNA) protein coding sequences most intensively studied. These changes, in genes such as MAP3K7, BRD9, and ABCB7, typically lead to loss of function, thus contributing to cancer pathogenesis. Here, we systematically analyzed the impact of mutant SF3B1 on noncoding regions of mRNA transcripts across disease types, in both cell lines and primary patient specimens. This identified numerous novel and highly reproducible splicing alterations in such regions. Studies of a target gene, DCAF16, revealed multiple complex mutation-induced alterations in its 5' and 3' untranslated regions (UTRs). Remarkably, these were mechanistically associated with increased DCAF16 protein levels in SF3B1-mutant cells, representing, to our knowledge, the first time that oncogenic SF3B1 has been found to increase levels of a target protein in a gain-of-function manner. DCAF16 is a substrate recognition adapter for the DDB1/CUL4 E3 ubiquitin ligase complex. Novel protein degrader small molecules that coopt DCAF16 to degrade BRD4 as a neosubstrate demonstrated preferential selectivity for SF3B1-mutant cancers and CLL primary patient specimens due to increased DCAF16 protein levels. In turn, this reveals the therapeutic relevance of mutant SF3B1 dysregulation of transcript UTRs and uncovers a novel strategy for the treatment of these important neoplasms.

Humans↗

PubMed2026

Systems genetics approaches model the heritable architecture of polyendocrine metabolic ovarian syndrome.

Polyendocrine metabolic ovarian syndrome (PMOS), formerly known as polycystic ovary syndrome (PCOS), is the most common endocrine disorder in women and is closely associated with complex diseases such as cardiovascular disease and type 2 diabetes. However, the mechanistic links between PMOS and its comorbidities remain poorly understood. Here, we present an integrative systems genetics platform that leverages genetic diversity in both mice and humans to dissect the drivers of PMOS and its associated complications. This framework uncovered conserved genetic and environmental factors underlying PMOS, identified susceptible cell types and organs, and elucidated mechanisms linking PMOS to subsequent pathologies. For instance, we showed that increased ovarian area contributes to both PMOS susceptibility and ovarian cancer progression, while specific ovary-heart signaling circuits modulate cardiac function with aging. We further identified ovarian SF3B1-mediated alternative splicing as a key mechanistic link between PMOS and metabolic traits. Pharmacologic inhibition of SF3B1 in mice reduced circulating testosterone, insulin, and glucose levels as well as fat mass expansion. Transcriptomics analysis of ovaries from mice and experiments using human cell lines localized these effects to exon skipping events in granulosa cells. Together, this study offers a mechanistic framework for modeling the diversity of PMOS pathologies and uncovers SF3B1-mediated splicing as a link between ovary function and systemic metabolism.

Female↗

PubMed2026

Mutational Landscape and Clonal Dynamics in AML Undergoing PTCy Hematopoietic Cell Transplantation.

To improve risk stratification, we performed targeted NGS at diagnosis in 191 patients with AML undergoing myeloablative allogeneic HCT with PTCy-based prophylaxis. We also investigated clonal evolution using paired diagnostic and relapse samples from 39 individuals. A total of 610 mutations were detected in 184 patients (96%), most commonly in FLT3 (26%), DNMT3A (25%), RUNX1 (24%), and NPM1 (19%). Sixteen unique fusion genes were identified in 35 patients, with KMT2A (43%) and core binding factor rearrangements (23%) being the most frequent. TP53 and WT1 mutations were strongly associated with adverse outcomes, whereas NPM1 retained favorable significance. RUNX1 co-mutations with SF3B1 or NRAS were associated with inferior survival. In an exploratory allelic analysis, multi-hit TP53 alterations, but not single-hit mutations, were associated with distinctly poorer OS, EFS, and relapse risk. Relapse involved mutational shifts in ∼70% of cases, with significant enrichment of WT1 and more modest increases in TP53, KRAS, ASXL1, NF1, and MECOM, while DNMT3A, TET2, and ASXL1 persisted stably. Neither acute nor chronic graft-versus-host disease was associated with molecular remodeling at relapse. Incorporating TP53 and WT1 into risk models, recognizing context-dependent effects of DNMT3A and RUNX1, and applying longitudinal genomic monitoring may help guide personalized strategies to prevent relapse. Extended abstract BACKGROUND Relapse remains the leading cause of treatment failure after allogeneic hematopoietic cell transplantation (HCT) for acute myeloid leukemia (AML), yet the genetic mechanisms underlying post-transplant relapse remain poorly understood, particularly in the era of post-transplant cyclophosphamide (PTCy). Characterizing the mutational landscape at diagnosis and the clonal evolution leading to relapse may improve post-transplant risk stratification and identify opportunities for personalized surveillance and intervention. OBJECTIVES To characterize the diagnostic mutational landscape, evaluate its prognostic significance, and investigate clonal evolution from diagnosis to relapse in AML patients undergoing myeloablative HCT with PTCy-based graft-versus-host disease prophylaxis. STUDY DESIGN We performed targeted next-generation sequencing (NGS) at diagnosis in 191 consecutive AML patients undergoing myeloablative allogeneic HCT with PTCy-based prophylaxis. Paired diagnostic and relapse samples were available for 39 patients to evaluate clonal evolution. RESULTS A total of 610 mutations were detected in 184 patients (96%), most commonly in FLT3 (26%), DNMT3A (25%), RUNX1 (24%), and NPM1 (19%). Sixteen unique fusion genes were identified in 35 patients, with KMT2A (43%) and core binding factor rearrangements (23%) being the most frequent. TP53 and WT1 mutations were strongly associated with adverse outcomes, whereas NPM1 retained favorable significance. RUNX1 co-mutations with SF3B1 or NRAS were associated with inferior survival. In an exploratory allelic analysis, multi-hit TP53 alterations, but not single-hit mutations, were associated with distinctly poorer OS, EFS, and relapse risk. Relapse involved mutational shifts in ∼70% of cases, with significant enrichment of WT1 and more modest increases in TP53, KRAS, ASXL1, NF1, and MECOM, while DNMT3A, TET2, and ASXL1 persisted stably. Neither acute nor chronic graft-versus-host disease was associated with molecular remodeling at relapse. CONCLUSIONS This study provides a comprehensive characterization of the mutational landscape and clonal evolution of AML undergoing contemporary PTCy-based allogeneic HCT. TP53 and WT1 identify patients at particularly high risk of post-transplant relapse, whereas NPM1 retains favorable prognostic significance. The frequent acquisition of new genetic lesions at relapse underscores the dynamic nature of post-transplant clonal evolution and supports longitudinal molecular monitoring together with genomically informed post-transplant surveillance and relapse-prevention strategies.

Clonal Dynamics↗

PubMed2026

Somatic genetic alterations in pituitary neuroendocrine tumors.

The molecular characterization of pituitary neuroendocrine tumors (PitNETs) has progressed pronouncedly in recent years, unraveling the molecular pathways driving initiation and progression of different PitNET types and allowing a better understanding of their biology. The most frequent recurring somatic driver alterations were recognized in corticotroph PitNETs (USP8, USP48, BRAF) and somatotroph PitNETs (GNAS) and, much less frequently, in lactotroph PitNETs (SF3B1). Additional well-characterized somatic driver alterations, including TP53, ATRX, and DAXX, are enriched in aggressive corticotroph tumors. Identification of new molecular markers and delineation of their clinical phenotypes are enabling further subclassification of PitNETs based on tumor molecular profiles, with earlier recognition of more aggressive variants. These molecular markers also provide an opportunity for new targeted therapies. Beyond single-gene alterations, epigenetic modifications, such as DNA methylation, histone modifications, and noncoding RNA dysregulation, are emerging as important contributors to PitNET pathogenesis and potential therapeutic targets. Multi-omics approaches encompassing genomics, transcriptomics, epigenomics, and proteomics are transforming PitNET classification. In this review, we provide a comprehensive, data-driven update on somatic driver alterations, epigenetic alterations, converging signaling pathways, and the related emerging therapeutic targets in PitNETs, integrating pooled analyses from published cohorts.

Humans↗

PubMed2026

Prognostic impact of age and MDS-associated mutations in NPM1-mutated AML.

Nucleophosmin-1 (NPM1) mutations define a major molecular subtype of acute myeloid leukemia (AML) and is generally associated with favorable prognosis. However, the impact of myelodysplastic syndrome-associated mutations (MDSm+) on patient outcomes within this subgroup remains uncertain. We retrospectively analyzed 271 patients with NPM1-mutated AML from 3 independent cohorts (SWOG, Fred Hutch, and Beat AML) to assess the prognostic significance of MDSm+ and its interaction with age. MDSm+ occurred in 17% of patients, most commonly involving SRSF2 and SF3B1. Although MDSm+ was associated with inferior overall survival (OS) compared with MDSm- in European LeukemiaNet (ELN) 2022 favorable-risk patients (hazard ratio [HR], 2.0; P = .008), this effect was largely driven by worse outcomes in older patients (≥65 years) as older ELN2022 favorable-risk patients had poor OS regardless of the presence of MDSm+ compared with younger patients. After stratification of patients by age, there was not a significant difference between MDSm+ and MDSm- in either younger patients (HR, 0.99; P = .98) or older patients (HR, 1.42; P = .33). These findings indicate that MDSm+ in NPM1 + AML is not independently associated with adverse risk after adjusting for age, and highlight the need for age-adjusted AML risk models.

Journal Article↗

PubMed2026

Genome-wide CRISPR screens map synthetic lethal interactions across recurrent cancer driver alterations.

Synthetic lethality (SL) provides a treatment paradigm for targeting cancer with alterations in driver genes that are not conventionally druggable, including tumor suppressor genes. We execute a series of genome-wide CRISPR screens using functionally validated isogenic cell lines and conduct a large-scale SL analysis using data from the cancer dependency map (DepMap). We chart SL interactions across 15 driver alterations: FBXW7, CCNE1, CDK12, ARID1A, KMT2D, DNMT3A, TET2, KEAP1, STK11, IDH1, SF3B1, SRSF2, U2AF1, chromosome 18q loss, and chromosome 13q loss. We show validation of several SL interactions, including ARID1A and the hexosamine biosynthetic pathway aminotransferase GFPT1, STK11 with CAMK protein kinase MARK2, FBXW7 and the CDK1 regulatory kinase PKMYT1, and CCNE1 amplification and the anaphase-promoting complex or cyclosome (APC/C). In summary, this study offers a rich resource of genetic interactions across cancer drivers enabling the discovery of biological insights and drug targets for future therapeutic development.

CP: cancer↗

PubMed2026

Genome-Wide Impact of Human DBR1 Depletion on RNA Processing Networks Reveal a Connection Between Pre-mRNA Splicing, mRNA Surveillance and Stress Granule Dynamics.

The RNA lariat debranching enzyme DBR1 is essential for intron turnover and RNA metabolism, yet its broader impact on transcriptome regulation remains incompletely defined. To elucidate the consequences of DBR1 depletion, we performed transcriptome-wide RNA sequencing of DBR1-knockdown and wild-type HEK293 cells. Differential expression analysis revealed widespread perturbations in pathways linked to RNA splicing, mRNA surveillance, translational control, and stress-granule biology. Many of the most significantly altered transcripts encode splicing factors and RNA quality-control components, underscoring DBR1's influence on post-transcriptional regulation. Alternative splicing analysis showed changes across multiple event types, with exon skipping accounting for >50% of events, followed by mutually exclusive exons, alternative 5' and 3' splice sites, and retained introns, indicating that DBR1 depletion induces pervasive splicing defects. Direct spliceosome inhibition using isoginkgetin (blocks tri-snRNP recruitment) and pladienolide B (targets SF3B1) reproduced the DBR1-KD mis-splicing patterns of cell signaling genes and factors involved in RNA metabolism, supporting a functional link between DBR1 activity and alternative splicing. Notably, DBR1 knockdown revealed a subset of transcripts that are both NMD-sensitive and enriched within stress granules. Consistent with this observation, G3BP1 immunopurification and confocal microscopy further support a role for DBR1 and UPF1 in stress-granule dynamics, suggesting that these factors may participate at distinct stages to influence mRNA fate under stress conditions. Together, these findings indicate that DBR1 functions beyond lariat RNA turnover as a common regulator of RNA processing, transcriptome stability, and stress granule homeostasis, revealing intricate crosstalk between RNA splicing and RNA quality control pathways in human cells.

Humans↗