Small molecule-based targeting of chromatin regulatory factors has emerged as a promising therapeutic strategy in recent years. The development and ongoing clinical evaluation of novel agents ...targeting a range of chromatin regulatory processes, including DNA or histone modifiers, histone readers, and chromatin regulatory protein complexes, has inspired the field to identify and act upon the full compendium of therapeutic opportunities. Emerging studies highlight the frequent involvement of altered mammalian Switch/Sucrose-Nonfermentable (mSWI/SNF) chromatin-remodeling complexes (also called BAF complexes) in both human cancer and neurological disorders, suggesting new mechanisms and accompanying routes toward therapeutic intervention. Here, we review current approaches for direct targeting of mSWI/SNF complex structure and function and discuss settings in which aberrant mSWI/SNF biology is implicated in oncology and other diseases.
Over 20% of human cancers carry a mutation in mSWI/SNF complex subunit genes.Mistargeting of mSWI/SNF activity by disease-relevant transcription factors contributes to oncogenic gene expression programs.Targetable synthetic lethal opportunities exist for cancers harboring perturbations in mSWI/SNF subunits.The presence of alternate mSWI/SNF complex subtypes and variants enables complex-specific pharmacological targeting.Discovery and development of novel, subunit-specific small-molecule inhibitors and degraders are ongoing.
Alterations in transcriptional regulators can orchestrate oncogenic gene expression programs in cancer. Here, we show that the BRG1/BRM-associated factor (BAF) chromatin remodeling complex, which is ...mutated in over 20% of human tumors, interacts with EWSR1, a member of a family of proteins with prion-like domains (PrLD) that are frequent partners in oncogenic fusions with transcription factors. In Ewing sarcoma, we find that the BAF complex is recruited by the EWS-FLI1 fusion protein to tumor-specific enhancers and contributes to target gene activation. This process is a neomorphic property of EWS-FLI1 compared to wild-type FLI1 and depends on tyrosine residues that are necessary for phase transitions of the EWSR1 prion-like domain. Furthermore, fusion of short fragments of EWSR1 to FLI1 is sufficient to recapitulate BAF complex retargeting and EWS-FLI1 activities. Our studies thus demonstrate that the physical properties of prion-like domains can retarget critical chromatin regulatory complexes to establish and maintain oncogenic gene expression programs.
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•EWS-FLI1 binds and recruits BAF complexes to GGAA microsatellites in Ewing sarcoma•De novo enhancer activation at GGAA repeats is a neomorphic property of EWS-FLI1•The EWS-FLI1 PrLD is necessary for phase transitions and de novo enhancer activation•Small PrLD fragments fused to FLI1 are sufficient to recapitulate EWS-FLI1 activity
Phase transition properties of a prion-like domain in an oncogenic fusion protein are critical for retargeting BAF chromatin remodeling complexes and activating enhancers, thereby driving the transcriptional program that promotes Ewing sarcoma.
IMPORTANCE: The effect of high-flow oxygen therapy vs conventional oxygen therapy has not been established in the setting of severe COVID-19. OBJECTIVE: To determine the effect of high-flow oxygen ...therapy through a nasal cannula compared with conventional oxygen therapy on need for endotracheal intubation and clinical recovery in severe COVID-19. DESIGN, SETTING, AND PARTICIPANTS: Randomized, open-label clinical trial conducted in emergency and intensive care units in 3 hospitals in Colombia. A total of 220 adults with respiratory distress and a ratio of partial pressure of arterial oxygen to fraction of inspired oxygen of less than 200 due to COVID-19 were randomized from August 2020 to January 2021, with last follow-up on February 10, 2021. INTERVENTIONS: Patients were randomly assigned to receive high-flow oxygen through a nasal cannula (n = 109) or conventional oxygen therapy (n = 111). MAIN OUTCOMES AND MEASURES: The co–primary outcomes were need for intubation and time to clinical recovery until day 28 as assessed by a 7-category ordinal scale (range, 1-7, with higher scores indicating a worse condition). Effects of treatments were calculated with a Cox proportional hazards model adjusted for hypoxemia severity, age, and comorbidities. RESULTS: Among 220 randomized patients, 199 were included in the analysis (median age, 60 years; n = 65 women 32.7%). Intubation occurred in 34 (34.3%) randomized to high-flow oxygen therapy and in 51 (51.0%) randomized to conventional oxygen therapy (hazard ratio, 0.62; 95% CI, 0.39-0.96; P = .03). The median time to clinical recovery within 28 days was 11 (IQR, 9-14) days in patients randomized to high-flow oxygen therapy vs 14 (IQR, 11-19) days in those randomized to conventional oxygen therapy (hazard ratio, 1.39; 95% CI, 1.00-1.92; P = .047). Suspected bacterial pneumonia occurred in 13 patients (13.1%) randomized to high-flow oxygen and in 17 (17.0%) of those randomized to conventional oxygen therapy, while bacteremia was detected in 7 (7.1%) vs 11 (11.0%), respectively. CONCLUSIONS AND RELEVANCE: Among patients with severe COVID-19, use of high-flow oxygen through a nasal cannula significantly decreased need for mechanical ventilation support and time to clinical recovery compared with conventional low-flow oxygen therapy. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04609462
Two recent studies demonstrate the power of integrating tumor genotype information with epigenetic and proteomic studies to discover potential therapeutic targets in breast cancer.
DNA double-strand breaks (DSBs) activate a canonical DNA damage response, including highly conserved cell cycle checkpoint pathways that prevent cells with DSBs from progressing through the cell ...cycle. In developing B cells, pre-B cell receptor (pre-BCR) signals initiate immunoglobulin light (Igl) chain gene assembly, leading to RAG-mediated DNA DSBs. The pre-BCR also promotes cell cycle entry, which could cause aberrant DSB repair and genome instability in pre-B cells. Here, we show that RAG DSBs inhibit pre-BCR signals through the ATM- and NF-κB2-dependent induction of SPIC, a hematopoietic-specific transcriptional repressor. SPIC inhibits expression of the SYK tyrosine kinase and BLNK adaptor, resulting in suppression of pre-BCR signaling. This regulatory circuit prevents the pre-BCR from inducing additional Igl chain gene rearrangements and driving pre-B cells with RAG DSBs into cycle. We propose that pre-B cells toggle between pre-BCR signals and a RAG DSB-dependent checkpoint to maintain genome stability while iteratively assembling Igl chain genes.
Chromosomal rearrangements resulting in the fusion of TMPRSS2, an androgen-regulated gene, and the ETS family transcription factor ERG occur in over half of prostate cancers. However, the mechanism ...by which ERG promotes oncogenic gene expression and proliferation remains incompletely understood. Here, we identify a binding interaction between ERG and the mammalian SWI/SNF (BAF) ATP-dependent chromatin remodeling complex, which is conserved among other oncogenic ETS factors, including ETV1, ETV4, and ETV5. We find that ERG drives genome-wide retargeting of BAF complexes in a manner dependent on binding of ERG to the ETS DNA motif. Moreover, ERG requires intact BAF complexes for chromatin occupancy and BAF complex ATPase activity for target gene regulation. In a prostate organoid model, BAF complexes are required for ERG-mediated basal-to-luminal transition, a hallmark of ERG activity in prostate cancer. These observations suggest a fundamental interdependence between ETS transcription factors and BAF chromatin remodeling complexes in cancer.
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•ERG binds to BAF complexes in solution and in a DNA-independent manner•ERG targets BAF complexes to ETS motif sites genome-wide•BAF complex ATPase activity is required for ERG target gene regulation•BAF complexes are required for ERG-mediated basal-to-luminal transition
Sandoval et al. demonstrate that binding of the ERG transcription factor to BAF chromatin remodeling complexes drives genome-wide BAF complex retargeting and gene regulation. BAF complex ATPase activity is required for ERG-mediated target gene regulation in cell line and organoid models, demonstrating an interdependency between ERG and BAF complexes in prostate cancer.
Objective
To determine the acceptance rate of treatment alternatives for women with either preinvasive conditions or gynecologic cancers during the COVID‐19 pandemic among Latin American ...gynecological cancer specialists.
Methods
Twelve experts in gynecological cancer designed an electronic survey, according to recommendations from international societies, using an online platform. The survey included 22 questions on five topics: consultation care, preinvasive cervical pathology, and cervical, ovarian, and endometrial cancer. The questionnaire was distributed to 1052 specialists in 14 Latin American countries. A descriptive analysis was carried out using statistical software.
Results
A total of 610 responses were received, for an overall response rate of 58.0%. Respondents favored offering teleconsultation as triage for post‐cancer treatment follow‐up (94.6%), neoadjuvant chemotherapy in advanced stage epithelial ovarian cancer (95.6%), and total hysterectomy with bilateral salpingo‐oophorectomy and defining adjuvant treatment with histopathological features in early stage endometrial cancer (85.4%). Other questions showed agreement rates of over 64%, except for review of pathology results in person and use of upfront concurrent chemoradiation for early stage cervical cancer (disagreement 56.4% and 58.9%, respectively).
Conclusion
Latin American specialists accepted some alternative management strategies for gynecological cancer care during the COVID‐19 pandemic, which may reflect the region’s particularities.
The COVID‐19 pandemic led Latin American specialists to accept alternative management strategies for gynecological cancer care, especially regarding surgical decisions.
The COVID‐19 pandemic led Latin American specialists to accept alternative management strategies for gynecological cancer care, especially regarding surgical decisions.
Androgen-receptor (AR) inhibitors, including enzalutamide, are used for treatment of all metastatic castration-resistant prostate cancers (mCRPCs). However, some patients develop resistance or never ...respond. We find that the transcription factor CREB5 confers enzalutamide resistance in an open reading frame (ORF) expression screen and in tumor xenografts. CREB5 overexpression is essential for an enzalutamide-resistant patient-derived organoid. In AR-expressing prostate cancer cells, CREB5 interactions enhance AR activity at a subset of promoters and enhancers upon enzalutamide treatment, including MYC and genes involved in the cell cycle. In mCRPC, we found recurrent amplification and overexpression of CREB5. Our observations identify CREB5 as one mechanism that drives resistance to AR antagonists in prostate cancers.
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•CREB5 promotes resistance to AR inhibitors and androgen therapies in prostate cancer•CREB5 selectively enhances interaction of AR with target genes critical for survival•CREB5 is amplified or overexpressed in therapy-resistant metastatic prostate cancers•Targeting CREB5 is effective in patient-derived models that are therapy resistant
Advanced prostate cancers develop resistance to androgen receptor (AR)-targeting therapies. Hwang et al. show that resistant prostate cancers overexpress or amplify CREB5, mediating resistance to AR inhibition. CREB5 suppression reduces the viability of therapy-resistant patient-derived models, suggesting that CREB5 is a target in prostate cancer patients with limited treatment options.
Antineutrophil cytoplasmic antibody-associated vasculitides (AAVs) are uncommon systemic autoimmune diseases, of which few reports exist in Latin America. Our aim was to examine AAV evaluated in a ...high-complexity hospital in southwestern Colombia, with emphasis in severe forms.
A medical records review study of 67 patients was performed, and data were collected from electronic registries. Moderate and severe AAVs were defined as the presence of life-threatening complications, unfavorable Birmingham Vasculitis Activity Score outcomes, and hospitalization requirements at the time of diagnosis and by the last follow-up, between 2011 and 2019. Clinical manifestations, treatment, and outcomes were evaluated. The AAV subtypes were compared.
A total of 67 cases were included. The majority were female (n = 44, 65.67%), and the median age was 52 (40-64) years. Granulomatosis with polyangiitis (GPA) was the most frequent with 42 patients (62.68%), followed by microscopic polyangiitis (MPA) and eosinophilic GPA, with 15 patients (22.38%) and 10 patients (14.92%), respectively. Forty-four patients (65.67%) presented pulmonary symptoms. The highest Birmingham Vasculitis Activity Score corresponded to MPA, with 21 (12-25) points. Fifteen patients (22.4%) were admitted to the intensive care unit throughout the course of the disease, of whom 10 had GPA. The longest stay and duration of mechanical ventilation were seen in MPA. The principal treatments were corticosteroids and cyclophosphamide, and the main outcome was end-stage renal disease.
In this cohort of AAV, most of cases corresponded to GPA, and pulmonary manifestations were the most common. Microscopic polyangiitis was the more severe subtype as it showed worse impairment in clinical characteristics and intensive care unit requirements.
Mammalian ortholog of Drosophila cell polarity protein, Dlg1, plays a critical role in neural synapse formation, epithelial cell homeostasis, and urogenital development. More recently, it has been ...proposed that Dlg1 may also be involved in the regulation of T‐cell proliferation, migration, and Ag‐receptor signaling. However, a requirement for Dlg1 in development and function of T lineage cells remains to be established. In this study, we investigated a role for Dlg1 during T‐cell development and function using a combination of conditional Dlg1 KO and two different Cre expression systems where Dlg1 deficiency is restricted to the T‐cell lineage only, or all hematopoietic cells. Here, using three different TCR models, we show that Dlg1 is not required during development and selection of thymocytes bearing functionally rearranged TCR transgenes. Moreover, Dlg1 is dispensable in the activation and proliferative expansion of Ag‐specific TCR‐transgenic CD4+ and CD8+ T cells in vitro and in vivo. Surprisingly, however, we show that Dlg1 is required for normal generation of memory T cells during endogenous response to cognate Ag. Thus, Dlg1 is not required for the thymocyte selection or the activation of primary T cells, however it is involved in the generation of memory T cells.
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