t temporal patterning predicts stimulus-dependent synchrony in nearby cells sharing input with similar spectrotemporal structure, which in turn can sharpen the downstream readout of sound direction. This work shows how stimulus-dependent spike timing can affect the downstream coding of sound location by firing rate, a mechanism that can be generalized to sensory neurons sensitive to the temporal structure of the stimulus. Copyright © 2020 Beckert et al.Altered synaptic function is thought to play a role in many neurodegenerative diseases, but little is known about the underlying mechanisms for synaptic dysfunction. The squid giant synapse (SGS) is a classical model for studying synaptic electrophysiology and ultrastructure, as well as molecular mechanisms of neurotransmission. Here, we conduct a multidisciplinary study of synaptic actions of misfolded human G85R-SOD1 causing familial Amyotrophic Lateral Sclerosis (fALS). G85R-SOD1, but not WT-SOD1, inhibited synaptic transmission, altered presynaptic ultrastructure, and reduced both the size of the Readily Releasable Pool (RRP) of synaptic vesicles and mobility from the Reserved Pool (RP) to the RRP. Unexpectedly, intermittent high frequency stimulation (iHFS) blocked inhibitory effects of G85R-SOD1 on synaptic transmission, suggesting aberrant Ca2+ signaling may underlie G85R-SOD1 toxicity. Ratiometric Ca2+ imaging showed significantly increased presynaptic Ca2+ induced by G85R-SOD1 that preceded synaptic to an effective therapeutic intervention as well as identify biomarkers for early diagnosis. https://www.selleckchem.com/products/17-AAG(Geldanamycin).html Furthermore, the altered synaptic vesicle behavior and Ca2+ dynamics revealed through the perturbation of neurotransmission by ALS extends our understanding of fundamental synaptic physiology at both molecular and cellular levels. Copyright © 2020 Song.Mutations in protein-coding genes are well established as the basis for human cancer, yet it remains elusive how alterations within non-coding genome, a substantial fraction of which contain cis-regulatory elements (CREs), contribute to cancer pathophysiology. Here, we developed an integrative approach to systematically identify and characterize non-coding regulatory variants with functional consequences in human hematopoietic malignancies. Combining targeted resequencing of hematopoietic lineage-associated CREs and mutation discovery, we uncovered 1,836 recurrently mutated CREs containing leukemia-associated non-coding variants. By enhanced CRISPR/dCas9-based CRE perturbation screening and functional analyses, we identified 218 variant-associated oncogenic or tumor suppressive CREs in human leukemia. Non-coding variants at KRAS and PER2 enhancers reside in proximity to nuclear receptor (NR) binding regions and modulate transcriptional activities in response to NR signaling in leukemia cells. NR binding sites frequently co-localize with non-coding variants across cancer types. Hence, recurrent non-coding variants connect enhancer dysregulation with nuclear receptor signaling in hematopoietic malignancies. Copyright ©2020, American Association for Cancer Research.Epithelial plasticity - reversible modulation of a cell's epithelial and mesenchymal features - is associated with tumor metastasis and chemoresistance, leading causes of cancer mortality. While different master transcription factors and epigenetic modifiers have been implicated in this process in various contexts, the extent to which a unifying, generalized mechanism of transcriptional regulation underlies epithelial plasticity remains largely unknown. Here, through targeted CRISPR-Cas9 screening, we discovered two histone-modifying enzymes involved in the writing and erasing of H3K36me2 that act reciprocally to regulate epithelial-mesenchymal identity, tumor differentiation, and metastasis. Using a K-to-M histone mutant to directly inhibit H3K36me2, we found that global modulation of the mark is a conserved mechanism underlying the mesenchymal state in various contexts. Mechanistically, regulation of H3K36me2 reprograms enhancers associated with master regulators of epithelial-mesenchymal state. Our results thus outline a unifying epigenome-scale mechanism by which a specific histone modification regulates cellular plasticity and metastasis in cancer. Copyright ©2020, American Association for Cancer Research.Although mutations in the RNA splicing factor SF3B1 are frequent in multiple cancers, their functional effects and therapeutic dependencies are poorly understood. Here we characterize 98 tumors and 12 isogenic cell lines harboring SF3B1 hotspot mutations, identifying hundreds of cryptic 3' splice sites common and specific to different cancer types. Regulatory network analysis revealed that the most common SF3B1 mutation activates ****via effects conserved across human and mouse cells. SF3B1 mutations promote decay of transcripts encoding the PP2A phosphatase subunit PPP2R5A, increasing c-****S62 and BCL2 S70 phosphorylation which, in turn, promote ****protein stability and impair apoptosis, respectively. Genetic PPP2R5A restoration or pharmacologic PP2A activation impaired SF3B1-mutant tumorigenesis elucidating a therapeutic approach to aberrant splicing by mutant SF3B1. Copyright ©2020, American Association for Cancer Research.BACKGROUND Patients with advanced rare cancers have poor prognosis and few treatment options. As immunotherapy is effective across multiple cancer types, we aimed to assess pembrolizumab (programmed cell death 1 (PD-1) inhibitor) in patients with advanced rare cancers. METHODS In this open-label, phase 2 trial, patients with advanced rare cancers whose tumors had progressed on standard therapies, if available, within the previous 6 months were enrolled in nine tumor-specific cohorts and a 10th cohort for other rare histologies. Pembrolizumab 200 mg was administered intravenously every 21 days. The primary endpoint was non-progression rate (NPR) at 27 weeks; secondary endpoints were safety and tolerability, objective response rate (ORR), and clinical benefit rate (CBR). RESULTS A total of 127 patients treated between August 15, 2016 and July 27, 2018 were included in this analysis. At the time of data cut-off, the NPR at 27 weeks was 28% (95% CI, 19% to 37%). A confirmed objective response (OR) was seen in 15 of 110 (14%) evaluable patients (complete response in one and partial response in 14).
t temporal patterning predicts stimulus-dependent synchrony in nearby cells sharing input with similar spectrotemporal structure, which in turn can sharpen the downstream readout of sound direction. This work shows how stimulus-dependent spike timing can affect the downstream coding of sound location by firing rate, a mechanism that can be generalized to sensory neurons sensitive to the temporal structure of the stimulus. Copyright © 2020 Beckert et al.Altered synaptic function is thought to play a role in many neurodegenerative diseases, but little is known about the underlying mechanisms for synaptic dysfunction. The squid giant synapse (SGS) is a classical model for studying synaptic electrophysiology and ultrastructure, as well as molecular mechanisms of neurotransmission. Here, we conduct a multidisciplinary study of synaptic actions of misfolded human G85R-SOD1 causing familial Amyotrophic Lateral Sclerosis (fALS). G85R-SOD1, but not WT-SOD1, inhibited synaptic transmission, altered presynaptic ultrastructure, and reduced both the size of the Readily Releasable Pool (RRP) of synaptic vesicles and mobility from the Reserved Pool (RP) to the RRP. Unexpectedly, intermittent high frequency stimulation (iHFS) blocked inhibitory effects of G85R-SOD1 on synaptic transmission, suggesting aberrant Ca2+ signaling may underlie G85R-SOD1 toxicity. Ratiometric Ca2+ imaging showed significantly increased presynaptic Ca2+ induced by G85R-SOD1 that preceded synaptic to an effective therapeutic intervention as well as identify biomarkers for early diagnosis. https://www.selleckchem.com/products/17-AAG(Geldanamycin).html Furthermore, the altered synaptic vesicle behavior and Ca2+ dynamics revealed through the perturbation of neurotransmission by ALS extends our understanding of fundamental synaptic physiology at both molecular and cellular levels. Copyright © 2020 Song.Mutations in protein-coding genes are well established as the basis for human cancer, yet it remains elusive how alterations within non-coding genome, a substantial fraction of which contain cis-regulatory elements (CREs), contribute to cancer pathophysiology. Here, we developed an integrative approach to systematically identify and characterize non-coding regulatory variants with functional consequences in human hematopoietic malignancies. Combining targeted resequencing of hematopoietic lineage-associated CREs and mutation discovery, we uncovered 1,836 recurrently mutated CREs containing leukemia-associated non-coding variants. By enhanced CRISPR/dCas9-based CRE perturbation screening and functional analyses, we identified 218 variant-associated oncogenic or tumor suppressive CREs in human leukemia. Non-coding variants at KRAS and PER2 enhancers reside in proximity to nuclear receptor (NR) binding regions and modulate transcriptional activities in response to NR signaling in leukemia cells. NR binding sites frequently co-localize with non-coding variants across cancer types. Hence, recurrent non-coding variants connect enhancer dysregulation with nuclear receptor signaling in hematopoietic malignancies. Copyright ©2020, American Association for Cancer Research.Epithelial plasticity - reversible modulation of a cell's epithelial and mesenchymal features - is associated with tumor metastasis and chemoresistance, leading causes of cancer mortality. While different master transcription factors and epigenetic modifiers have been implicated in this process in various contexts, the extent to which a unifying, generalized mechanism of transcriptional regulation underlies epithelial plasticity remains largely unknown. Here, through targeted CRISPR-Cas9 screening, we discovered two histone-modifying enzymes involved in the writing and erasing of H3K36me2 that act reciprocally to regulate epithelial-mesenchymal identity, tumor differentiation, and metastasis. Using a K-to-M histone mutant to directly inhibit H3K36me2, we found that global modulation of the mark is a conserved mechanism underlying the mesenchymal state in various contexts. Mechanistically, regulation of H3K36me2 reprograms enhancers associated with master regulators of epithelial-mesenchymal state. Our results thus outline a unifying epigenome-scale mechanism by which a specific histone modification regulates cellular plasticity and metastasis in cancer. Copyright ©2020, American Association for Cancer Research.Although mutations in the RNA splicing factor SF3B1 are frequent in multiple cancers, their functional effects and therapeutic dependencies are poorly understood. Here we characterize 98 tumors and 12 isogenic cell lines harboring SF3B1 hotspot mutations, identifying hundreds of cryptic 3' splice sites common and specific to different cancer types. Regulatory network analysis revealed that the most common SF3B1 mutation activates MYC via effects conserved across human and mouse cells. SF3B1 mutations promote decay of transcripts encoding the PP2A phosphatase subunit PPP2R5A, increasing c-MYC S62 and BCL2 S70 phosphorylation which, in turn, promote MYC protein stability and impair apoptosis, respectively. Genetic PPP2R5A restoration or pharmacologic PP2A activation impaired SF3B1-mutant tumorigenesis elucidating a therapeutic approach to aberrant splicing by mutant SF3B1. Copyright ©2020, American Association for Cancer Research.BACKGROUND Patients with advanced rare cancers have poor prognosis and few treatment options. As immunotherapy is effective across multiple cancer types, we aimed to assess pembrolizumab (programmed cell death 1 (PD-1) inhibitor) in patients with advanced rare cancers. METHODS In this open-label, phase 2 trial, patients with advanced rare cancers whose tumors had progressed on standard therapies, if available, within the previous 6 months were enrolled in nine tumor-specific cohorts and a 10th cohort for other rare histologies. Pembrolizumab 200 mg was administered intravenously every 21 days. The primary endpoint was non-progression rate (NPR) at 27 weeks; secondary endpoints were safety and tolerability, objective response rate (ORR), and clinical benefit rate (CBR). RESULTS A total of 127 patients treated between August 15, 2016 and July 27, 2018 were included in this analysis. At the time of data cut-off, the NPR at 27 weeks was 28% (95% CI, 19% to 37%). A confirmed objective response (OR) was seen in 15 of 110 (14%) evaluable patients (complete response in one and partial response in 14).
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