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Swi-independent 3a and 3b (Sin3a and Sin3b) are paralogous transcriptional coregulators that direct cellular differentiation, survival, and function. Here, we report that mouse Sin3a and Sin3b are coproduced in most pancreatic cells during embryogenesis but become much more enriched in endocrine cells in adults, implying continued essential roles in mature endocrine cell function. Mice with loss of in endocrine progenitors were normal during early postnatal stages but gradually developed diabetes before weaning. These physiological defects were preceded by the compromised survival, insulin-vesicle packaging, insulin secretion, and nutrient-induced Ca influx of -deficient β-cells. RNA sequencing coupled with candidate chromatin immunoprecipitation assays revealed several genes that could be directly regulated by Sin3a in β-cells, which modulate Ca/ion transport, cell survival, vesicle/membrane trafficking, glucose metabolism, and stress responses. Finally, mice with loss of both and in multipotent embryonic pancreatic progenitors had significantly reduced islet cell mass at birth, caused by decreased endocrine progenitor production and increased β-cell death. These findings highlight the stage-specific requirements for the presumed "general" coregulators Sin3a and Sin3b in islet β-cells, with Sin3a being dispensable for differentiation but required for postnatal function and survival.
© 2020 by the American Diabetes Association.
BACKGROUND - Human papillomavirus 16 (HPV-16) E6 seropositivity is a promising early marker of human papillomavirus-driven oropharyngeal cancer (HPV-OPC), yet more sensitive imaging modalities are needed before screening is considered. The objective of this study was to determine the sensitivity of transcervical sonography (TCS) for detecting clinically apparent HPV-OPC in comparison with computed tomography (CT) and positron emission tomography (PET)/CT.
METHODS - Fifty-one patients with known or suspected HPV-OPC without prior treatment underwent oropharyngeal TCS and blood collection (for HPV multiplex serology testing). Eight standard sonographic images were collected; primary-site tumors were measured in 3 dimensions if identified. Each patient underwent a full diagnostic workup as part of standard clinical care. The pathologic details, HPV status, final staging, and imaging findings were abstracted from the medical record. The sensitivity of each imaging modality was compared with the final clinical diagnosis (the gold standard).
RESULTS - Twenty-four base of tongue cancers (47%), 22 tonsillar cancers (43%), and 2 unknown primary cancers (4%) were diagnosed; 3 patients (6%) had no tumors. All p16-tested patients were positive (n = 47). Primary-site tumors were correctly identified in 90.2% (95% confidence interval [CI], 78.6%-96.7%) with TCS, in 69.4% (95% CI, 54.6%-81.7%) with CT, and in 83.3% (95% CI, 68.6%-93.0%) with PET/CT. TCS identified tumors in 10 of 14 cases missed by CT and recognized the absence of tumors in 3 cases for which CT or PET/CT was falsely positive. The smallest sonographically identified primary-site tumor was 0.5 cm in its greatest dimension; the average size was 2.3 cm. Among p16-positive patients, 76.1% (95% CI, 61.2%-87.4%) were seropositive for HPV-16 E6.
CONCLUSIONS - TCS and HPV-16 E6 antibodies are sensitive for the diagnosis of HPV-OPC.
© 2020 American Cancer Society.
Histone deacetylase 3 (Hdac3) is a target of the FDA approved HDAC inhibitors, which are used for the treatment of lymphoid malignancies. Here, we used Cd19-Cre to conditionally delete Hdac3 to define its role in germinal center B cells, which represent the cell of origin for many B cell malignancies. Cd19-Cre-Hdac3-/- mice showed impaired germinal center formation along with a defect in plasmablast production. Analysis of Hdac3-/- germinal centers revealed a reduction in dark zone centroblasts and accumulation of light zone centrocytes. RNA-seq revealed a significant correlation between genes up-regulated upon Hdac3 loss and those up-regulated in Foxo1-deleted germinal center B cells, even though Foxo1 typically activates transcription. Therefore, to determine whether gene expression changes observed in Hdac3-/- germinal centers were a result of direct effects of Hdac3 deacetylase activity, we used an HDAC3 selective inhibitor and examined nascent transcription in germinal center-derived cell lines. Transcriptional changes upon HDAC3 inhibition were enriched for light zone gene signatures as observed in germinal centers. Further comparison of PRO-seq data with ChIP-seq/exo data for BCL6, SMRT, FOXO1 and H3K27ac identified direct targets of HDAC3 function including CD86, CD83 and CXCR5 that are likely responsible for driving the light zone phenotype observed in vivo.
© The Author(s) 2019. Published by Oxford University Press on behalf of Nucleic Acids Research.
The myeloid translocation gene family member MTG16 is a transcriptional corepressor that relies on the DNA-binding ability of other proteins to determine specificity. One such protein is the ZBTB family member Kaiso, and the MTG16:Kaiso interaction is necessary for repression of Kaiso target genes, such as matrix metalloproteinase-7. Using the azoxymethane and dextran sodium sulfate (AOM/DSS) murine model of colitis-associated carcinoma, we previously determined that MTG16 loss accelerates tumorigenesis and inflammation. However, it was unknown whether this effect was modified by Kaiso-dependent transcriptional repression. To test for a genetic interaction between MTG16 and Kaiso in inflammatory carcinogenesis, we subjected single and double knockout (DKO) mice to the AOM/DSS protocol. Mtg16 mice demonstrated increased colitis and tumor burden; in contrast, disease severity in Kaiso mice was equivalent to wild-type controls. Surprisingly, Kaiso deficiency in the context of MTG16 loss reversed injury and pro-tumorigenic responses in the intestinal epithelium following AOM/DSS treatment, and tumor numbers were returned to near to wild-type levels. Transcriptomic analysis of non-tumor colon tissue demonstrated that changes induced by MTG16 loss were widely mitigated by concurrent Kaiso loss, and DKO mice demonstrated downregulation of metabolism and cytokine-associated gene sets with concurrent activation of DNA damage checkpoint pathways as compared with Mtg16. Further, Kaiso knockdown in intestinal enteroids reduced stem- and WNT-associated phenotypes, thus abrogating the induction of these pathways observed in Mtg16 samples. Together, these data suggest that Kaiso modifies MTG16-driven inflammation and tumorigenesis and suggests that Kaiso deregulation contributes to MTG16-dependent colitis and CAC phenotypes.
is a Gram-negative opportunistic pathogen that causes diverse infections, including pneumonia, bacteremia, and wound infections. Due to multiple intrinsic and acquired antimicrobial-resistance mechanisms, isolates are commonly multidrug resistant, and infections are notoriously difficult to treat. The World Health Organization recently highlighted carbapenem-resistant as a "critical priority" for the development of new antimicrobials because of the risk to human health posed by this organism. Therefore, it is important to discover the mechanisms used by to survive stresses encountered during infection in order to identify new drug targets. In this study, by use of imaging, we identified hydrogen peroxide (HO) as a stressor produced in the lung during infection and defined OxyR as a transcriptional regulator of the HO stress response. Upon exposure to HO, differentially transcribes several hundred genes. However, the transcriptional upregulation of genes predicted to detoxify hydrogen peroxide is abolished in an strain in which the transcriptional regulator is genetically inactivated. Moreover, inactivation of in both antimicrobial-susceptible and multidrug-resistant strains impairs growth in the presence of HO OxyR is a direct regulator of and , which encode the major HO-degrading enzymes in , as confirmed through measurement of promoter binding by recombinant OxyR in electromobility shift assays. Finally, an mutant is less fit than wild-type during infection of the murine lung. This work reveals a mechanism used by this important human pathogen to survive HO stress encountered during infection.
Copyright © 2018 American Society for Microbiology.
Although the MYC oncogene has been implicated in cancer, a systematic assessment of alterations of MYC, related transcription factors, and co-regulatory proteins, forming the proximal MYC network (PMN), across human cancers is lacking. Using computational approaches, we define genomic and proteomic features associated with MYC and the PMN across the 33 cancers of The Cancer Genome Atlas. Pan-cancer, 28% of all samples had at least one of the MYC paralogs amplified. In contrast, the MYC antagonists MGA and MNT were the most frequently mutated or deleted members, proposing a role as tumor suppressors. MYC alterations were mutually exclusive with PIK3CA, PTEN, APC, or BRAF alterations, suggesting that MYC is a distinct oncogenic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such as immune response and growth factor signaling; chromatin, translation, and DNA replication/repair were conserved pan-cancer. This analysis reveals insights into MYC biology and is a reference for biomarkers and therapeutics for cancers with alterations of MYC or the PMN.
Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.
Heme is a cofactor that is essential for cellular respiration and for the function of many enzymes. If heme levels become too low within the cell, S. aureus switches from producing energy via respiration to producing energy by fermentation. S. aureus encodes two heme oxygenases, IsdI and IsdG, which cleave the porphyrin heme ring releasing iron for use as a nutrient source. Both isdI and isdG are only expressed under low iron conditions and are regulated by the canonical Ferric Uptake Regulator (Fur). Here we demonstrate that unregulated expression of isdI and isdG within S. aureus leads to reduced growth under low iron conditions. Additionally, the constitutive expression of these enzymes leads to decreased heme abundance in S. aureus, an increase in the fermentation product lactate, and increased resistance to gentamicin. This work demonstrates that S. aureus has developed tuning mechanisms, such as Fur regulation, to ensure that the cell has sufficient quantities of heme for efficient ATP production through aerobic respiration.
Copyright © 2018 Elsevier GmbH. All rights reserved.
BACKGROUND - Human papillomavirus 16 (HPV16) E6 antibodies may be an early marker of the diagnosis and recurrence of human papillomavirus-driven oropharyngeal cancer (HPV-OPC).
METHODS - This study identified 161 incident oropharyngeal cancer (OPC) cases diagnosed at the University of Pittsburgh (2003-2013) with pretreatment serum. One hundred twelve had preexisting clinical HPV testing with p16 immunohistochemistry and HPV in situ hybridization (87 were dual-positive [HPV-OPC], and 25 were dual-negative [HPV-negative]); 62 had at least 1 posttreatment serum sample. Eighty-six of the 161 tumors were available for additional HPV16 DNA/RNA testing (45 were dual-positive [HPV16-OPC], and 19 were dual-negative [HPV16-negative). HPV16 E6 antibody testing was conducted with multiplex serology. The following were evaluated: 1) the sensitivity and specificity of HPV16 E6 serology for distinguishing HPV-OPC and HPV16-OPC from HPV-negative OPC, 2) HPV16 E6 antibody decay after treatment with linear models accommodating correlations in variance estimates, and 3) pre- and posttreatment HPV16 E6 levels and the risk of recurrence with Cox proportional hazards models.
RESULTS - Seventy-eight of 87 HPV-OPCs were HPV16 E6-seropositive (sensitivity, 89.7%; 95% confidence interval [CI], 81.3%-95.2%), and 24 of 25 HPV-negative OPCs were HPV16 E6-seronegative (specificity, 96.0%; 95% CI, 79.6%-99.9%). Forty-two of 45 HPV16-OPCs were HPV16 E6-seropositive (sensitivity, 93.3%; 95% CI, 81.7%-98.6%), and 18 of 19 HPV16-negative OPCs were HPV16 E6-seronegative (specificity, 94.7%; 95% CI, 74.0%-99.9%). Posttreatment HPV16 E6 antibody levels did not decrease significantly from the baseline (P = .575; median follow-up, 307 days) and were not associated with the risk of recurrence. However, pretreatment HPV16 E6 seropositivity was associated with an 86% reduced risk of local/regional recurrence (hazard ratio, 0.14; 95% CI, 0.03-0.68; P = .015).
CONCLUSIONS - HPV16 E6 antibodies may have potential clinical utility for the diagnosis and/or prognosis of HPV-OPC. Cancer 2017;123:4382-90. © 2017 American Cancer Society.
© 2017 American Cancer Society.
Imbalances in secretory proteostasis induced by genetic, environmental, or aging-related insults are pathologically associated with etiologically diverse protein misfolding diseases. To protect the secretory proteome from these insults, organisms evolved stress-responsive signaling pathways that regulate the composition and activity of biologic pathways involved in secretory proteostasis maintenance. The most prominent of these is the endoplasmic reticulum (ER) unfolded protein response (UPR), which functions to regulate ER proteostasis in response to ER stress. While the signaling mechanisms involved in UPR activation are well defined, the impact of UPR activation on secretory proteostasis is only now becoming clear. Here, we highlight recent reports defining how activation of select UPR signaling pathways influences proteostasis within the ER and downstream secretory environments. Furthermore, we describe recent evidence that highlights the therapeutic potential for targeting UPR signaling pathways to correct pathologic disruption in secretory proteostasis associated with diverse types of protein misfolding diseases.
Copyright © 2017 Elsevier Ltd. All rights reserved.
Background - In a European cohort, it was previously reported that 35% of oropharyngeal cancer (OPC) patients were human papillomavirus type-16 (HPV16) seropositive up to 10 years before diagnosis vs 0.6% of cancer-free controls. Here, we describe the kinetics of HPV16-E6 antibodies prior to OPC diagnosis.
Methods - We used annual serial prediagnostic blood samples from the PLCO Cancer Screening Trial. Antibodies to HPV were initially assessed in prediagnostic blood drawn at study enrollment from 198 incident head and neck cancer patients (median years to cancer diagnosis = 6.6) and 924 matched control subjects using multiplex serology, and subsequently in serial samples (median = 5/individual). Available tumor samples were identified and tested for HPV16 RNA to define HPV-driven OPC.
Results - HPV16-E6 antibodies were present at baseline in 42.3% of 52 OPC patients and 0.5% of 924 control subjects. HPV16-E6 antibody levels were highly elevated and stable across serial blood samples for 21 OPC patients who were seropositive at baseline, as well as for one OPC patient who seroconverted closer to diagnosis. All five subjects with HPV16-driven OPC tumors were HPV16-E6-seropositive, and the four subjects with HPV16-negative OPC tumors were seronegative. The estimated 10-year cumulative risk of OPC was 6.2% (95% confidence interval [CI] = 1.8% to 21.5%) for HPV16-E6-seropositive men, 1.3% (95% CI = 0.1% to 15.3%) for HPV16-E6-seropositive women, and 0.04% (95% CI = 0.03% to 0.06%) among HPV16-E6-seronegative individuals.
Conclusions - Forty-two percent of subjects diagnosed with OPC between 1994 and 2009 in a US cohort were HPV16-E6 seropositive, with stable antibody levels during annual follow-up for up to 13 years prior to diagnosis. Tumor analysis indicated that the sensitivity and specificity of HPV16-E6 antibodies were exceptionally high in predicting HPV-driven OPC.
Published by Oxford University Press 2017. This work is written by US Government employees and is in the public domain in the US.