Search Results (78)

Background/Objectives: SCCOHT is an aggressive and often fatal cancer that belongs to the ~20% of cancers defined by mutations to subunits of the SWI/SNF chromatin remodeling complex. In SCCOHT, mutations to the SMARCA4 gene, which encodes the SWI/SNF ATPase BRG1, are sufficient to impair SWI/SNF function. This single genetic lesion leads to a cascade of events that promote tumorigenesis, some of which may involve the intersection of SWI/SNF with oncogenic pathways such as those regulated by the MYC oncogene. In SCCOHT tumors and other cancers marked by SWI/SNF subunit mutation, MYC target genes are recurrently activated, pointing to a relationship between SWI/SNF and MYC that has yet to be fully explored. Methods: In this study, we investigate the contribution of MYC to SCCOHT biology by performing a combination of chromatin binding and transcriptome assays in genetically engineered SCCOHT cell lines, with subsequent validation using patient tumor expression data. Results: We find that MYC binds to thousands of active promoters in the BIN-67 SCCOHT cell line and that the depletion of MYC results in a broad range of gene expression changes with a notable effect on the expression of genes related to DNA repair. We uncover an MYC-regulated DNA repair gene expression program in BIN-67 cells that is antagonized by BRG1 reintroduction. Finally, we identify a DNA repair gene signature that is upregulated in SCCOHT tumors and in tumors defined by loss of the SWI/SNF subunit SNF5. Conclusions: Collectively, these data implicate MYC as a robust regulator of DNA repair gene expression in SCCOHT and lay a foundation for future studies focused on interrogating the relationship between BRG1 and MYC. Full article

Skeletal muscle is the largest heterogeneous organ in the body, and multiple factors in intrinsic genetic and epigenetic regulation influence its growth. The N⁶-methyladenosine ed(m⁶A) modification is a conserved and most prevalent RNA modification, whose function is dependent on m⁶A writers, erasers, and m⁶A readers, such as the YTH protein family. YTHDC1 is the only member of the YTH protein family member that exists in the cell nucleus, which plays an important role in mRNA alternative polyadenylation and alternative splicing processes. However, the function of YTHDC1 in regulating myoblast proliferation, differentiation, and in vivo skeletal muscle development remains unclear. Therefore, in this study, we studied the function of YTHDC1 in C2C12 cell line and mouse. Our results showed that YTHDC1 significantly promoted myogenic differentiation while inhibiting myoblast proliferation in C2C12 cells, and the results of our in vivo experiment showed that interfering with YTHDC1 led to a significant enhancement of muscle growth in mice. Furthermore, the transcriptome sequencing analysis revealed that YTHDC1 might modulate skeletal muscle development by regulating alternative splicing of genes, including Akap13, Smarca2, Tnnt3, and Neb. Our study shed light on understanding the function and molecular mechanisms of YTHDC1 in regulating skeletal muscle development, highlighting the critical contribution of m⁶A-mediated RNA splicing in muscle growth. These results indicated that YTHDC1 could be a potential breeding target gene to enhance meat quality in livestock. Full article

Atypical teratoid rhabdoid tumor (ATRT) is a rare, aggressive pediatric central nervous system (CNS) tumor that predominantly affects children under the age of 3. It is defined by the inactivation of the SMARCB1 gene, leading to the loss of INI1, a protein essential for cell lineage determination and cell differentiation. Current standard of care treatment requires aggressive multimodal therapy with maximal safe resection, high-dose chemotherapy with autologous stem cell rescue, and radiation, yet overall survival remains < 50%. These intensive regimens have improved overall survival but are associated with significant morbidity and long-term effects. Molecular profiling has significantly advanced the understanding of ATRTs, revealing four molecular subgroups, ATRT-TYR, ATRT-MYC, ATRT-SHH, and ATRT-SMARCA4, each with distinct clinical presentations, oncogenic pathways, and prognoses. Molecular characterization enables better prognostic stratification, guiding treatment decisions and allowing for more personalized therapeutic approaches. Targeted therapies based on these molecular insights remain experimental, and continued exploration of molecular mechanisms and how they differ amongst subgroups is pivotal for the development of less toxic, more effective targeted treatments. Full article

CAV1 is a protein-coding gene linked to several disorders, including cancer, lipodystrophy, and cardiovascular diseases. While its ability to respond to various mechanical and metabolic stimuli has been documented, a comprehensive understanding of its physiological regulation in humans is lacking. We leveraged the comprehensiveness of human post-mortem tissue data from the Genotype-Tissue Expression (GTEx) consortium, systematically exploring the sources of variability in CAV1 transcriptional levels using extensive bulk and single-nuclei RNA-seq datasets. This human-centric approach, avoiding inter-species comparisons, constitutes a unique resource to explore CAV1 regulation within the complexity of human tissues. Notably, cell type proportion was identified as a major determinant of CAV1 transcription levels across tissues. Donor physiological conditions, including disease states and end-of-life circumstances, also exhibited a tissue-specific influence. Among primary upstream regulators associated with CAV1, chromatin modifiers stood out, especially SMARCA2, which showed a positive correlation across tissues, and PRC2 complexes, which exhibited tissue-specific correlation. Upstream regulatory networks determining CAV1 levels are also enriched for annotations such as mechanobiology (e.g., TEAD4), immunity (e.g., RELA and STAT3), and metabolism (e.g., MYC and NRF1). A remarkable observation was a strong correlation between CAV1 and the relative infiltration of immune cells across tissues, supporting a potential role for CAV1 as a marker and driver of tissue immune infiltration. Full article

Background: Understanding PIK3CA mutations and co-mutations in non-small cell lung carcinoma (NSCLC) is critical to developing personalized treatment strategies. Therefore, this study aims to investigate PIK3CA mutations and the accompanying somatic variations in NSCLC. Methods: This retrospective study included 98 patients over 18 years of age who were diagnosed with NSCLC, operated on, and referred to the Molecular Pathology Laboratory between January 2019 and June 2024 for next-generation sequencing panel tests and ALK-ROS1 FISH analysis. Results: All patients were found to carry PIK3CA mutations. Among the 98 NSCLC patients analyzed, 16 (16.33%) were female and 82 (83.67%) were male. The average age of the patients was 64.53 ± 9.63 years, with an age range of 38–84 years, and the majority were 50 years or older. Of the cases, 51 presented the adenocarcinoma subtype, while the remaining 47 showed the squamous cell carcinoma subtype. A smoking history was present in 77 (78.57%) patients, while 21 (21.43%) had no smoking history. The most frequently detected pathogenic or likely pathogenic PIK3CA variations were c.1633G>A p.E545K (32.65%), c.1624G>A p.E542K (11.22%), c.3140A>G p.H1047R (11.22%), c.3140A>T p.H1047L (5.10%), c.1357G>C p.E453Q (4.08%), and c.3143A>G p.H1048R (2.04%). The top 10 mutations that most commonly accompanied PIK3CA variations were KRAS, NF1, TP53, EGFR, PTEN, BRAF, KIT, CDKN2A, SMARCA4, and ATM mutations, respectively. Conclusions: PIK3CA variations, along with other gene variations, may influence cancer progression and thus may play a crucial role in the determination of targeted treatment strategies. Full article

Sinonasal carcinomas are aggressive neoplasms that present a high morbidity and mortality rate with an unfavorable prognosis. This group of tumors exhibits morphological and genetic diversity. Genetic and epigenetic alterations in these neoplasms are the current targets for diagnosis and treatment. The most common type of cancer originating in the sinonasal tract is sinonasal squamous cell carcinomas (SNSCCs), which present different histological patterns and variable histological aggressiveness. A significant number of alterations have been reported in sinonasal tumors, including deficiencies in the Switch/Sucrose non-fermentable (SWI/SNF) chromatin remodeling complex. In the sinonasal tract, deficiencies of the subunits SMARCB1/INI1, SMARCA4/BRG1, and SMARCA2 have been noted in carcinomas, adenocarcinomas, and soft tissue tumors with a distinctive high-grade morphology and a fatal prognosis. Objective: The objective of this study is to identify the status of the SWI/SNF complex using immunohistochemistry in sinonasal squamous cell carcinomas and their association with morphology and survival. Methods: A total of 103 sinonasal carcinomas with different grades of squamous differentiation were analyzed; the selection was based on those cases with high-grade morphology. The carcinomas were then evaluated immunohistochemically for SMARCB1 and SMARCA4 proteins. Their expression was compared with the biological behavior and survival of the patients. Results: Among the SNSCCs, 47% corresponded to the non-keratinizing squamous cell carcinoma (NKSCC) type with high-grade characteristics, 40% were keratinizing squamous cell carcinomas (KSCCs), 9% were SMARCB1-deficient carcinomas, and 4% were SMARCA4-deficient carcinomas. Mosaic expression for SMARCB1 (NKSCC—33%; KSCC—21.9%) and SMARCA4 (NKSCC—14.6%; KSCC—12.2%) was identified, showing an impact on tumor size and progression. Conclusions: We identified that that the partial loss (mosaic expression) of SMARCB1 in SNSCCs is associated with high-grade malignant characteristics and a negative effect on patient survival; meanwhile, SMARCA4-mosaic expression in SNSCCs is associated with high-grade malignant characteristics and an increase in tumor size concerning the intact SMARCA4. Full article

SWI/SNF (SWItch/Sucrose Non-Fermentable) is the most frequently mutated chromatin-remodelling complex in human malignancy, with over 20% of tumours having a mutation in a SWI/SNF complex member. Mutations in specific SWI/SNF complex members are characteristic of rare chemoresistant ovarian cancer histopathological subtypes. Somatic mutations in ARID1A, encoding one of the mutually exclusive DNA-binding subunits of SWI/SNF, occur in 42–67% of ovarian clear cell carcinomas (OCCC). The concomitant somatic or germline mutation and epigenetic silencing of the mutually exclusive ATPase subunits SMARCA4 and SMARCA2, respectively, occurs in Small cell carcinoma of the ovary, hypercalcaemic type (SCCOHT), with SMARCA4 mutation reported in 69–100% of SCCOHT cases and SMARCA2 silencing seen 86–100% of the time. Somatic ARID1A mutations also occur in endometrioid ovarian cancer (EnOC), as well as in the chronic benign condition endometriosis, possibly as precursors to the development of the endometriosis-associated cancers OCCC and EnOC. Mutation of the ARID1A paralogue ARID1B can also occur in both OCCC and SCCOHT. Mutations in other SWI/SNF complex members, including SMARCA2, SMARCB1 and SMARCC1, occur rarely in either OCCC or SCCOHT. Abrogated SWI/SNF raises opportunities for pharmacological inhibition, including the use of DNA damage repair inhibitors, kinase and epigenetic inhibitors, as well as immune checkpoint blockade. Full article

(1) Background: SMARCA4-deficient undifferentiated uterine sarcoma (SDUS) is a rare and aggressive cancer that urgently requires novel therapeutic strategies. Despite the proven efficacy of immunotherapy in various cancer types, its application in SDUS remains largely unexplored. This study aims to investigate the immune microenvironment of SDUS to evaluate the feasibility of utilizing immunotherapy. (2) Methods: Multiplex immunofluorescence (mIF) was employed to examine the immune microenvironment in two cases of SDUS in comparison to other subtypes of endometrial stromal sarcomas (ESSs). This research involved a comprehensive evaluation of immune cell infiltration, cellular interactions, and spatial organization within the tumor immune microenvironment (TiME). Statistical analysis was performed to assess differences in immune cell densities and interactions between SDUS and other ESSs. (3) Results: SDUS exhibited a significantly higher density of cytotoxic T lymphocytes (CTLs), T helper (Th) cells, B cells, and macrophages compared to other ESSs. Notable cellular interactions included Th–CTL and Th–B cell interactions, which were more prominent in SDUS. The spatial analysis revealed distinct immune niches characterized by lymphocyte aggregation and a vascular-rich environment, suggesting an active and engaged immune microenvironment in SDUS. (4) Conclusions: The results suggest that SDUS exhibits a highly immunogenic TiME, characterized by substantial lymphocyte infiltration and dynamic cellular interactions. These findings highlight the potential of immunotherapy as an effective treatment approach for SDUS. However, given the small number of samples evaluated, these conclusions should be drawn with caution. This study underscores the importance of additional investigation into immune-targeted therapies for this challenging cancer subtype, with a larger sample size to validate and expand upon these preliminary findings. Full article

The innate immune system serves as the first line of defense against β-coronaviruses (β-CoVs), a family of viruses that includes SARS-CoV-2. Viral sensing via pattern recognition receptors triggers inflammation and cell death, which are essential components of the innate immune response that facilitate viral clearance. However, excessive activation of the innate immune system and inflammatory cell death can result in uncontrolled release of proinflammatory cytokines, resulting in cytokine storm and pathology. PANoptosis, innate immune, inflammatory cell death initiated by innate immune sensors and driven by caspases and RIPKs through PANoptosome complexes, has been implicated in the pathology of viral infections. Therefore, understanding the molecular mechanisms regulating PANoptosis in response to β-CoV infection is critical for identifying new therapeutic targets that can mitigate disease severity. In the current study, we analyzed findings from a cell death-based CRISPR screen with archetypal β-CoV mouse hepatitis virus (MHV) as the trigger to characterize host molecules required for inflammatory cell death. As a result, we identified SMARCA4, a chromatin regulator, as a putative host factor required for PANoptosis in response to MHV. Furthermore, we observed that gRNA-mediated deletion of Smarca4 inhibited MHV-induced PANoptotic cell death in macrophages. These findings have potential translational and clinical implications for the advancement of treatment strategies for β-CoVs and other infections. Full article

This critical review investigates the impact of SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, member 4 (SMARCA4) mutations on survival outcomes in non-small cell lung cancer (NSCLC) through an analysis of 21 peer-reviewed articles. Survival analyses across this review demonstrated consistently worse outcomes for SMARCA4-mutated vs. SMARCA4 wild-type NSCLC patients, specifically emphasizing class 1 truncating mutations as an independent factor for poor overall survival. In addition, this review explores the clinicopathologic characteristics of SMARCA4 mutations and their impact on various treatment modalities, including immune checkpoint inhibitors (ICIs) both with and without Kirsten rat sarcoma viral oncogene homolog (KRAS) co-mutations. The potential ineffectiveness of ICI treatment in NSCLC is explored through the impact of SMARCA4/KRAS co-mutations on the tumor microenvironment. Moreover, this NSCLC review consistently reported statistically worse overall survival outcomes for SMARCA4/KRAS co-mutations than SMARCA4 wild-type/KRAS-mutated cohorts, extending across ICIs, chemo-immunotherapy (CIT), and KRAS G12C inhibitors. Designing prospective clinical SMARCA4-mutated or SMARCA4/KRAS co-mutated NSCLC trials to evaluate targeted therapies and immunotherapy may lead to a better understanding of how to improve cancer patients’ outcomes and survival rates. Full article

Malignant rhabdoid tumors (MRTs) are among the most aggressive and treatment-resistant malignancies affecting infants, originating in the kidney, brain, liver, and soft tissues. The 5-year event-free survival rate for these cancers is a mere 20%. In nearly all cases of MRT, the SMARCB1 gene (occasionally SMARCA4)—a pivotal component of the SWI/SNF chromatin remodeling complex—is homozygously deleted, although the precise etiology of these tumors remains unknown. While young patients with localized MRT generally show improved outcomes, especially those who are older and have early-stage disease, the overall prognosis remains poor despite optimal standard treatments. This highlights the urgent need for more effective treatment strategies. We investigated the antitumor activity of a PARP1 inhibitor (talazoparib, TLZ) combined with a DNA alkylating agent (temozolomide, TMZ) in MRT xenograft models. PARP1 is a widely targeted molecule in cancer treatment and, beyond its role in DNA repair, it participates in transcriptional regulation by recruiting chromatin remodeling complexes to modulate DNA accessibility for RNA polymerases. To widen the therapeutic window of the drug combination, we employed PEGylated TLZ (PEG~TLZ), which has been reported to reduce systemic toxicity through slow drug release. Remarkably, our findings indicate that five out of six MRT xenografts exhibited an objective response to PEG~TLZ+TMZ therapy. Significantly, the loss of SMARCB1 was found to confer a protective effect, correlating with higher expression levels of DNA damage and repair proteins in SMARCB1-deficient MRT cells. Additionally, we identified MGMT as a potential biomarker indicative of in vivo MRT response to PEG~TLZ+TMZ therapy. Moreover, our analysis revealed alterations in signaling pathways associated with the observed antitumor efficacy. This study presents a novel and efficacious therapeutic approach for MRT, along with a promising candidate biomarker for predicting tumor response. Full article

Atypical teratoid/rhabdoid tumors (AT/RT) are highly aggressive tumors of the central nervous system (CNS), accounting for 1–3% of all pediatric CNS tumors. In general, AT/RTs are associated with biallelic inactivation of SMARCB1, resulting in the loss of expression of the integrase interactor 1 (INI1) protein. In this report, we describe the clinical course of an infant patient who presented with fatigue, postprandial vomiting, and disability of left side movement. Histological examination revealed classical features indicative of rhabdoid tumors, yet an atypical immunohistochemical profile with preserved INI1 expression was observed. Molecular diagnostics further elucidated the presence of a heterozygous frameshift variant, SMARCA4 c.2693del, p.(Asn898Thrfs*12), underscoring the distinctive genetic foundations of the case. Surgical resection of the tumor was administered with subsequent chemotherapy to the patient, but the condition worsened dynamically, and a decision was made to give the patient palliative therapy. We report on a patient with AT/RT caused by a rare mutation of the SMARCA4 gene and an aggressive course of disease to provide more information and characteristics of these tumors. Full article

Background: The clinical impact of SMARCA4 mutations (SMARCA4ms) in gastroesophageal adenocarcinoma (GEA) remains underexplored. This study aimed to examine the association of SMARCA4ms with clinical outcomes and co-occurrence with other gene mutations identified through a next-generation sequencing (NGS) panel in GEA patients. Methods: A total of 256 patients with metastatic or recurrent GEA who underwent NGS panel profiling at the MD Anderson Cancer Center between 2016 and 2022 were included. Comparative analyses were performed to assess clinical outcomes related to SMARCA4ms. The frequency and types of SMARCA4ms and their co-occurrence with other gene mutations were also examined. Results: SMARCA4ms were identified in 19 patients (7.4%). These SMARCA4ms were significantly associated with non-signet ring cell subtype (p = 0.044) and PD-L1 positive expression (p = 0.046). No difference in survival between the SMARCA4m and SMARCA4-normal group was observed (p = 0.84). There were significant associations between SMARCA4ms and FANCA, IGF1R, KRAS, FANCL, and PTEN alterations. Notably, 15 of the 19 SMARCA4m cases involved SNV missense mutations, with frequent co-occurrences noted with TP53, KRAS, ARID1A, and ERBB2 mutations. Conclusions: These results serve as the first comprehensive examination of the relationship between SMARCA4ms and clinical outcomes in GEA. Full article

Recently, the fifth edition of the WHO classification recognized the thoracic SMARCA4-deficient undifferentiated tumor (SMARCA4-UT) as a separate entity from conventional non-small cell lung cancer with SMARCA4 deficiency because of the different clinicopathological characteristics of these two diseases. SMARCA4-UT mainly occurs in young to middle-aged adults and involves a large mass compressing the tissues surrounding the mediastinum and lung parenchyma. Unfortunately, SMARCA4-UT shows a high probability of recurrence after upfront surgery as well as radiotherapy resistance; moreover, chemotherapy has low efficacy. Moreover, given the recent classification of SMARCA4-UT, no data concerning specific clinical trials are currently available. However, several case reports show immunotherapy efficacy in patients with this disease not only in a metastatic setting but also in a neoadjuvant manner, supporting the development of clinical trials. In addition, preclinical data and initial clinical experiences suggest that inhibiting pathways such as CDK4/6, AURKA, ATR, and EZH2 may be a promising therapeutic approach to SMARCA4-UT. Full article

Background: An atypical teratoid/rhabdoid tumor (AT/RT) is an uncommon and aggressive pediatric central nervous system neoplasm. However, a universal clinical consensus or reliable prognostic evaluation system for this malignancy is lacking. Our study aimed to develop a risk model based on comprehensive clinical data to assist in clinical decision-making. Methods: We conducted a retrospective study by examining data from the Surveillance, Epidemiology, and End Results (SEER) repository, spanning 2000 to 2019. The external validation cohort was sourced from the Children’s Hospital Affiliated to Chongqing Medical University, China. To discern independent factors affecting overall survival (OS) and cancer-specific survival (CSS), we applied Least Absolute Shrinkage and Selection Operator (LASSO) and Random Forest (RF) regression analyses. Based on these factors, we structured nomogram survival predictions and initiated a dynamic online risk-evaluation system. To contrast survival outcomes among diverse treatments, we used propensity score matching (PSM) methodology. Molecular data with the most common mutations in AT/RT were extracted from the Catalogue of Somatic Mutations in Cancer (COSMIC) database. Results: The annual incidence of AT/RT showed an increasing trend (APC, 2.86%; 95% CI:0.75–5.01). Our prognostic study included 316 SEER database participants and 27 external validation patients. The entire group had a median OS of 18 months (range 11.5 to 24 months) and median CSS of 21 months (range 11.7 to 29.2). Evaluations involving C-statistics, DCA, and ROC analysis underscored the distinctive capabilities of our prediction model. An analysis via PSM highlighted that individuals undergoing triple therapy (integrating surgery, radiotherapy, and chemotherapy) had discernibly enhanced OS and CSS. The most common mutations of AT/RT identified in the COSMIC database were SMARCB1, BRAF, SMARCA4, NF2, and NRAS. Conclusions: In this study, we devised a predictive model that effectively gauges the prognosis of AT/RT and briefly analyzed its genomic features, which might offer a valuable tool to address existing clinical challenges. Full article