RESUMEN
Primary ciliary dyskinesia (PCD) is a genetic condition that results in dysmotile cilia. The repercussions of cilia dysmotility and gene variants on the multiciliated cell remain poorly understood. We used single-cell RNA sequencing, proteomics, and advanced microscopy to compare primary culture epithelial cells from patients with PCD, their heterozygous mothers, healthy individuals, and induced pluripotent stem (iPS) cells generated from a PCD patient. Transcriptomic analysis revealed unique signatures in PCD airway cells compared to their mothers and healthy individuals. Gene expression in heterozygous mothers' cells diverged from both control and PCD cells, marked by increased inflammatory and cellular stress signatures. Primary and iPS-derived PCD multiciliated cells had increased expression of glutathione-S-transferases, GSTA2 and GSTA1, as well as NRF2 target genes, accompanied by elevated levels of reactive oxygen species (ROS). Immunogold labeling in human cilia and proteomic analysis of the ciliated organism, Chlamydomonas reinhardtii, demonstrated that GSTA2 localizes to motile cilia. Loss of human GSTA2 and C. reinhardtii GSTA resulted in slowed cilia motility pointing to local cilia regulatory roles. Our findings identify cellular responses unique to PCD variants and independent of environmental stress and uncover a dedicated ciliary GSTA2 pathway essential for normal motility that may be a therapeutic target.
RESUMEN
Squamous cell carcinomas (SCCs), including lung, head & neck, bladder, and skin SCCs often display constitutive activation of the KEAP1-NRF2 pathway. Constitutive activation is achieved through multiple mechanisms, including activating mutations in NFE2L2 (NRF2). To determine the functional consequences of Nrf2 activation on skin SCC development, we assessed the effects of mutant Nrf2E79Q expression, one of the most common activating mutations in human SCCs, on tumor promotion and progression in the mouse skin multistage carcinogenesis model using a DMBA-initiation/TPA-promotion protocol where the Hras A->T mutation (Q61L) is the canonical driver mutation. Nrf2E79Q expression was temporally and conditionally activated in the epidermis at two stages of tumor development: 1) after DMBA initiation in the epidermis but before cutaneous tumor development and 2) in pre-existing DMBA-initiated/TPA-promoted squamous papillomas. Expression of Nrf2E79Q in the epidermis after DMBA initiation but before tumor occurrence inhibited the development/promotion of 70% of squamous papillomas. However, the remaining papillomas often displayed non-canonical Hras and Kras mutations and enhanced progression to SCCs compared to control mice expressing wildtype Nrf2. Nrf2E79Q expression in pre-existing tumors caused rapid regression of 60% of papillomas. The remaining papillomas displayed the expected canonical Hras A->T mutation (Q61L) and enhanced progression to SCCs. These results demonstrate that mutant Nrf2E79Q enhances the promotion and progression of a subset of skin tumors and alters the frequency and diversity of oncogenic Ras mutations when expressed early after initiation.
Asunto(s)
Queratinocitos , Mutación , Factor 2 Relacionado con NF-E2 , Neoplasias Cutáneas , Factor 2 Relacionado con NF-E2/genética , Factor 2 Relacionado con NF-E2/metabolismo , Animales , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología , Neoplasias Cutáneas/metabolismo , Neoplasias Cutáneas/inducido químicamente , Ratones , Queratinocitos/metabolismo , Progresión de la Enfermedad , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , 9,10-Dimetil-1,2-benzantraceno/toxicidad , Humanos , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/metabolismo , Modelos Animales de Enfermedad , Regulación Neoplásica de la Expresión Génica , Acetato de Tetradecanoilforbol/toxicidadRESUMEN
The protection of the replication fork structure under stress conditions is essential for genome maintenance and cancer prevention. A key signaling pathway for fork protection involves TRPV2-mediated Ca2+ release from the ER, which is triggered after the generation of cytosolic DNA and the activation of cGAS/STING. This results in CaMKK2/AMPK activation and subsequent Exo1 phosphorylation, which prevent aberrant fork processing, thereby ensuring genome stability. However, it remains poorly understood how the TRPV2 channel is activated by the presence of cytosolic DNA. Here, through a genome-wide CRISPR-based screen, we identify TRPM8 channel-associated factor 1 (TCAF1) as a key factor promoting TRPV2-mediated Ca2+ release under replication stress or other conditions that activate cGAS/STING. Mechanistically, TCAF1 assists Ca2+ release by facilitating the dissociation of STING from TRPV2, thereby relieving TRPV2 repression. Consistent with this function, TCAF1 is required for fork protection, chromosomal stability, and cell survival after replication stress.
Asunto(s)
Calcio , Citosol , Replicación del ADN , Proteínas de la Membrana , Canales Catiónicos TRPV , Humanos , Canales Catiónicos TRPV/metabolismo , Canales Catiónicos TRPV/genética , Calcio/metabolismo , Citosol/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Células HEK293 , ADN/metabolismo , Células HeLa , Quinasa de la Proteína Quinasa Dependiente de Calcio-Calmodulina/metabolismo , Quinasa de la Proteína Quinasa Dependiente de Calcio-Calmodulina/genética , Fosforilación , Inestabilidad Genómica , Daño del ADN , AnimalesRESUMEN
Aberrant activation of the NRF2/NFE2L2 transcription factor commonly occurs in head and neck squamous cell carcinomas (HNSCC). Mouse model studies have shown that NRF2 activation alone does not result in cancer. When combined with classic oncogenes and at the right dose, NRF2 activation promotes tumor initiation and progression. Here we deleted the tumor suppressor genes p16INK4A and p53 (referred to as CP mice), which are commonly lost in human HNSCC, in the presence of a constitutively active NRF2E79Q mutant (CPN mice). NRF2E79Q expression in CPN mice resulted in squamous cell hyperplasia or dysplasia with hyperkeratosis in the esophagus, oropharynx, and forestomach. In addition, CPN mice displayed oral cavity squamous cell carcinoma (OSCC); CP mice bearing wild-type NRF2 expression did not develop oral cavity hyperplasia, dysplasia or OSCC. In both CP and CPN mice, we also observed predominantly abdominal sarcomas and carcinomas. Our data show that in the context of p53 and p16 tumor suppressor loss, NRF2 activation serves oncogenic functions to drive OSCC. CPN mice represent a new model for OSCC that closely reflects the genetics of human HNSCC. SIGNIFICANCE: Human squamous cancers frequently show constitutive NRF2 activation, associated with poorer outcomes and resistance to multiple therapies. Here, we report the first activated NRF2-driven and human-relevant mouse model of squamous cell carcinoma that develops in the background of p16 and p53 loss. The availability of this model will lead to a clearer understanding of how NRF2 contributes to the initiation, progression, and therapeutic response of OSCC.
Asunto(s)
Carcinoma de Células Escamosas , Neoplasias de Cabeza y Cuello , Neoplasias de la Boca , Animales , Humanos , Ratones , Carcinoma de Células Escamosas/genética , Modelos Animales de Enfermedad , Neoplasias de Cabeza y Cuello/genética , Hiperplasia/genética , Neoplasias de la Boca/genética , Factor 2 Relacionado con NF-E2/genética , Carcinoma de Células Escamosas de Cabeza y Cuello/genética , Proteína p53 Supresora de Tumor/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismoRESUMEN
Prior to the next generation sequencing and characterization of the tumor genome landscape, mutations in the SWI/SNF chromatin remodeling complex and the KEAP1-NRF2 signaling pathway were underappreciated. While these two classes of mutations appeared to independently contribute to tumor development, recent reports have demonstrated a mechanistic link between these two regulatory mechanisms in specific cancer types and cell models. In this work, we expand upon these data by exploring the relationship between mutations in BAF and PBAF subunits of the SWI/SNF complex and activation of NRF2 signal transduction across many cancer types. ARID1A/B mutations were strongly associated with NRF2 transcriptional activity in head and neck squamous carcinomas (HNSC). Many additional tumor types showed significant association between NRF2 signaling and mutation of specific components of the SWI/SNF complex. Different effects of BAF and PBAF mutations on the polarity of NRF2 signaling were observed. Overall, our results support a context-dependent functional link between SWI/SNF and NRF2 mutations across human cancers and implicate ARID1A inactivation in HPV-negative HNSC in promoting tumor progression and survival through activation of the KEAP1-NRF2 signaling pathway. The tumor-specific effects of these mutations open a new area of study for how mutations in the KEAP1-NRF2 pathway and the SWI/SNF complex contribute to cancer.
Asunto(s)
Proteínas de Unión al ADN , Neoplasias de Cabeza y Cuello , Factor 2 Relacionado con NF-E2 , Factores de Transcripción , Humanos , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Neoplasias de Cabeza y Cuello/genética , Proteína 1 Asociada A ECH Tipo Kelch/genética , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Mutación , Factor 2 Relacionado con NF-E2/genética , Factor 2 Relacionado con NF-E2/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Transducción de Señal/genética , Carcinoma de Células Escamosas de Cabeza y Cuello/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
The human kinome, with more than 500 proteins, is crucial for cell signaling and disease. Yet, about one-third of kinases lack in-depth study. The Data and Resource Generating Center for Understudied Kinases has developed multiple resources to address this challenge including creation of a heavy amino acid peptide library for parallel reaction monitoring and quantitation of protein kinase expression, use of understudied kinases tagged with a miniTurbo-biotin ligase to determine interaction networks by proximity-dependent protein biotinylation, NanoBRET probe development for screening chemical tool target specificity in live cells, characterization of small molecule chemical tools inhibiting understudied kinases, and computational tools for defining kinome architecture. These resources are available through the Dark Kinase Knowledgebase, supporting further research into these understudied protein kinases.
Asunto(s)
Proteínas Quinasas , Proteínas , Humanos , Proteínas Quinasas/metabolismo , ProteómicaRESUMEN
Host factors that define the cellular tropism of SARS-CoV-2 beyond the cognate ACE2 receptor are poorly defined. From a screen of human airway derived cell lines that express varying levels of ACE2/TMPRSS2, we found a subset that express comparably high endogenous levels of ACE2 but surprisingly did not support SARS-CoV-2 replication. Here we report that this resistance is mediated by a basally active cGAS-STING pathway culminating in interferon (IFN)-mediated restriction of SARS-CoV-2 replication at a post-entry step. Pharmacological inhibition of JAK1/2, depletion of the IFN-α receptor and cGAS-STING pathway effectors substantially increased SARS-CoV-2 replication in these cell models. While depletion of cGAS or STING was sufficient to reduce the preexisting levels of IFN-stimulated genes (ISGs), SARS-CoV-2 infection in STING knockout cells independently induced ISG expression. Remarkably, SARS-CoV-2-induced ISG expression in STING knockout cell as well as in primary human airway cultures was limited to uninfected bystander cells, demonstrating efficient antagonism of the type I/III IFN-pathway, but not viral sensing or IFN production, in productively infected cells. Of note, SARS-CoV-2-infected primary human airway cells also displayed markedly lower levels of STING expression, raising the possibility that SARS-CoV-2 can target STING expression or preferentially infect cells that express low levels of STING. Finally, ectopic ACE2 overexpression overcame the IFN-mediated blocks, suggesting the ability of SARS-CoV-2 to overcome these possibly saturable blocks to infection. Our study highlights that in addition to viral receptors, basal activation of the cGAS-STING pathway and innate immune defenses may contribute to defining SARS-CoV-2 cellular tropism.
RESUMEN
The NFE2L2 (NRF2) oncogene and transcription factor drives a gene expression program that promotes cancer progression, metabolic reprogramming, immune evasion, and chemoradiation resistance. Patient stratification by NRF2 activity may guide treatment decisions to improve outcome. Here, we developed a mass spectrometry-based targeted proteomics assay based on internal standard-triggered parallel reaction monitoring to quantify 69 NRF2 pathway components and targets, as well as 21 proteins of broad clinical significance in head and neck squamous cell carcinoma (HNSCC). We improved an existing internal standard-triggered parallel reaction monitoring acquisition algorithm, called SureQuant, to increase throughput, sensitivity, and precision. Testing the optimized platform on 27 lung and upper aerodigestive cancer cell models revealed 35 NRF2 responsive proteins. In formalin-fixed paraffin-embedded HNSCCs, NRF2 signaling intensity positively correlated with NRF2-activating mutations and with SOX2 protein expression. Protein markers of T-cell infiltration correlated positively with one another and with human papilloma virus infection status. CDKN2A (p16) protein expression positively correlated with the human papilloma virus oncogenic E7 protein and confirmed the presence of translationally active virus. This work establishes a clinically actionable HNSCC protein biomarker assay capable of quantifying over 600 peptides from frozen or formalin-fixed paraffin-embedded archived tissues in under 90 min.
Asunto(s)
Carcinoma de Células Escamosas , Neoplasias de Cabeza y Cuello , Infecciones por Papillomavirus , Humanos , Carcinoma de Células Escamosas de Cabeza y Cuello , Carcinoma de Células Escamosas/metabolismo , Factor 2 Relacionado con NF-E2 , Proteómica , Infecciones por Papillomavirus/genética , Infecciones por Papillomavirus/metabolismo , Biomarcadores de Tumor/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , Inhibidor p16 de la Quinasa Dependiente de Ciclina/uso terapéutico , FormaldehídoRESUMEN
Radiotherapy (RT) is one of the primary treatments of head and neck squamous cell carcinoma (HNSCC), which has a high-risk of locoregional failure (LRF). Presently, there is no reliable predictive biomarker of radioresistance in HNSCC. Here, we found that mutations in NFE2L2, which encodes Nrf2, are associated with a significantly higher rate of LRF in patients with oral cavity cancer treated with surgery and adjuvant (chemo)radiotherapy but not in those treated with surgery alone. Somatic mutation of NFE2L2 led to Nrf2 activation and radioresistance in HNSCC cells. Tumors harboring mutant Nrf2E79Q were substantially more radioresistant than tumors with wild-type Nrf2 in immunocompetent mice, whereas the difference was diminished in immunocompromised mice. Nrf2E79Q enhanced radioresistance through increased recruitment of intratumoral polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) and reduction of M1-polarized macrophages. Treatment with the glutaminase inhibitor CB-839 overcame the radioresistance induced by Nrf2E79Q or Nrf2E79K. RT increased expression of PMN-MDSC-attracting chemokines, including CXCL1, CXLC3, and CSF3, in Nrf2E79Q-expressing tumors via the TLR4, which could be reversed by CB-839. This study provides insights into the impact of NFE2L2 mutations on radioresistance and suggests that CB-839 can increase radiosensitivity by switching intratumoral myeloid cells to an antitumor phenotype, supporting clinical testing of CB-839 with RT in HNSCC with NFE2L2 mutations. SIGNIFICANCE: NFE2L2 mutations are predictive biomarkers of radioresistance in head and neck cancer and confer sensitivity to glutaminase inhibitors to overcome radioresistance.
Asunto(s)
Carcinoma de Células Escamosas , Neoplasias de Cabeza y Cuello , Células Supresoras de Origen Mieloide , Animales , Ratones , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/radioterapia , Carcinoma de Células Escamosas/patología , Glutaminasa/metabolismo , Neoplasias de Cabeza y Cuello/genética , Neoplasias de Cabeza y Cuello/radioterapia , Neoplasias de Cabeza y Cuello/metabolismo , Mutación , Células Supresoras de Origen Mieloide/metabolismo , Factor 2 Relacionado con NF-E2/genética , Factor 2 Relacionado con NF-E2/metabolismo , Tolerancia a Radiación/genética , Carcinoma de Células Escamosas de Cabeza y Cuello/genética , Carcinoma de Células Escamosas de Cabeza y Cuello/radioterapia , Carcinoma de Células Escamosas de Cabeza y Cuello/metabolismo , HumanosRESUMEN
STING is an innate immune sensor for immune surveillance of viral/bacterial infection and maintenance of an immune-friendly microenvironment to prevent tumorigenesis. However, if and how STING exerts innate immunity-independent function remains elusive. Here, the authors report that STING expression is increased in renal cell carcinoma (RCC) patients and governs tumor growth through non-canonical innate immune signaling involving mitochondrial ROS maintenance and calcium homeostasis. Mitochondrial voltage-dependent anion channel VDAC2 is identified as a new STING binding partner. STING depletion potentiates VDAC2/GRP75-mediated MERC (mitochondria-ER contact) formation to increase mitochondrial ROS/calcium levels, impairs mitochondria function, and suppresses mTORC1/S6K signaling leading to RCC growth retardation. STING interaction with VDAC2 occurs through STING-C88/C91 palmitoylation and inhibiting STING palmitoyl-transferases ZDHHCs by 2-BP significantly impedes RCC cell growth alone or in combination with sorafenib. Together, these studies reveal an innate immunity-independent function of STING in regulating mitochondrial function and growth in RCC, providing a rationale to target the STING/VDAC2 interaction in treating RCC.
Asunto(s)
Carcinoma de Células Renales , Neoplasias Renales , Humanos , Carcinoma de Células Renales/metabolismo , Calcio/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Mitocondrias/metabolismo , Inmunidad Innata , Microambiente Tumoral , Canal Aniónico 2 Dependiente del Voltaje/metabolismoRESUMEN
Aberrant activation or suppression of WNT/ß-catenin signaling contributes to cancer initiation and progression, neurodegeneration, and bone disease. However, despite great need and more than 40 years of research, targeted therapies for the WNT pathway have yet to be fully realized. Kinases are considered exceptionally druggable and occupy key nodes within the WNT signaling network, but several pathway-relevant kinases remain understudied and "dark." Here, we studied the function of the casein kinase 1γ (CSNK1γ) subfamily of human kinases and their roles in WNT signaling. miniTurbo-based proximity biotinylation and mass spectrometry analysis of CSNK1γ1, CSNK1γ2, and CSNK1γ3 revealed numerous components of the ß-catenin-dependent and ß-catenin-independent WNT pathways. In gain-of-function experiments, we found that CSNK1γ3 but not CSNK1γ1 or CSNK1γ2 activated ß-catenin-dependent WNT signaling, with minimal effect on other signaling pathways. We also show that within the family, CSNK1γ3 expression uniquely induced low-density lipoprotein receptor-related protein 6 phosphorylation, which mediates downstream WNT signaling transduction. Conversely, siRNA-mediated silencing of CSNK1γ3 alone had no impact on WNT signaling, though cosilencing of all three family members decreased WNT pathway activity. Finally, we characterized two moderately selective and potent small-molecule inhibitors of the CSNK1γ family. We show that these inhibitors and a CSNK1γ3 kinase-dead mutant suppressed but did not eliminate WNT-driven low-density lipoprotein receptor-related protein 6 phosphorylation and ß-catenin stabilization. Our data suggest that while CSNK1γ3 expression uniquely drives pathway activity, potential functional redundancy within the family necessitates loss of all three family members to suppress the WNT signaling pathway.
Asunto(s)
Quinasa de la Caseína I , Vía de Señalización Wnt , beta Catenina , Quinasa de la Caseína I/genética , Quinasa de la Caseína I/metabolismo , Humanos , Proteína-6 Relacionada a Receptor de Lipoproteína de Baja Densidad/genética , Proteína-6 Relacionada a Receptor de Lipoproteína de Baja Densidad/metabolismo , Fosforilación , Proteínas Wnt/metabolismo , beta Catenina/genética , beta Catenina/metabolismoRESUMEN
A wide range of protein acyl modifications has been identified on enzymes across various metabolic processes; however, the impact of these modifications remains poorly understood. Protein glutarylation is a recently identified modification that can be nonenzymatically driven by glutaryl-CoA. In mammalian systems, this unique metabolite is only produced in the lysine and tryptophan oxidative pathways. To better understand the biology of protein glutarylation, we studied the relationship between enzymes within the lysine/tryptophan catabolic pathways, protein glutarylation, and regulation by the deglutarylating enzyme sirtuin 5 (SIRT5). Here, we identify glutarylation on the lysine oxidation pathway enzyme glutaryl-CoA dehydrogenase (GCDH) and show increased GCDH glutarylation when glutaryl-CoA production is stimulated by lysine catabolism. Our data reveal that glutarylation of GCDH impacts its function, ultimately decreasing lysine oxidation. We also demonstrate the ability of SIRT5 to deglutarylate GCDH, restoring its enzymatic activity. Finally, metabolomic and bioinformatic analyses indicate an expanded role for SIRT5 in regulating amino acid metabolism. Together, these data support a feedback loop model within the lysine/tryptophan oxidation pathway in which glutaryl-CoA is produced, in turn inhibiting GCDH function via glutaryl modification of GCDH lysine residues and can be relieved by SIRT5 deacylation activity.
Asunto(s)
Glutaril-CoA Deshidrogenasa , Lisina , Sirtuinas , Animales , Glutaril-CoA Deshidrogenasa/metabolismo , Lisina/metabolismo , Ratones , Oxidación-Reducción , Procesamiento Proteico-Postraduccional , Sirtuinas/metabolismo , Triptófano/metabolismoRESUMEN
Emerging research supports that triclosan (TCS), an antimicrobial agent found in thousands of consumer products, exacerbates colitis and colitis-associated colorectal tumorigenesis in animal models. While the intestinal toxicities of TCS require the presence of gut microbiota, the molecular mechanisms involved have not been defined. Here we show that intestinal commensal microbes mediate metabolic activation of TCS in the colon and drive its gut toxicology. Using a range of in vitro, ex vivo, and in vivo approaches, we identify specific microbial ß-glucuronidase (GUS) enzymes involved and pinpoint molecular motifs required to metabolically activate TCS in the gut. Finally, we show that targeted inhibition of bacterial GUS enzymes abolishes the colitis-promoting effects of TCS, supporting an essential role of specific microbial proteins in TCS toxicity. Together, our results define a mechanism by which intestinal microbes contribute to the metabolic activation and gut toxicity of TCS, and highlight the importance of considering the contributions of the gut microbiota in evaluating the toxic potential of environmental chemicals.
Asunto(s)
Proteínas Bacterianas/antagonistas & inhibidores , Carcinógenos/antagonistas & inhibidores , Colitis/prevención & control , Neoplasias Colorrectales/prevención & control , Glucuronidasa/antagonistas & inhibidores , Inhibidores de Glicósido Hidrolasas/farmacología , Triclosán/antagonistas & inhibidores , Animales , Antiinfecciosos Locales/química , Antiinfecciosos Locales/metabolismo , Antiinfecciosos Locales/toxicidad , Anticarcinógenos/química , Anticarcinógenos/farmacología , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Sitios de Unión , Biotransformación , Carcinogénesis/efectos de los fármacos , Carcinogénesis/metabolismo , Carcinógenos/química , Carcinógenos/metabolismo , Carcinógenos/toxicidad , Colitis/inducido químicamente , Colitis/enzimología , Colitis/microbiología , Colon/efectos de los fármacos , Colon/microbiología , Colon/patología , Neoplasias Colorrectales/inducido químicamente , Neoplasias Colorrectales/enzimología , Neoplasias Colorrectales/microbiología , Microbioma Gastrointestinal/efectos de los fármacos , Expresión Génica , Glucuronidasa/química , Glucuronidasa/genética , Glucuronidasa/metabolismo , Inhibidores de Glicósido Hidrolasas/química , Humanos , Ratones , Ratones Endogámicos C57BL , Modelos Moleculares , Unión Proteica , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios y Motivos de Interacción de Proteínas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Triclosán/química , Triclosán/metabolismo , Triclosán/toxicidadRESUMEN
Homodimers are the most abundant type of enzyme in cells, and as such, they represent the most elemental system for studying the phenomenon of allostery. In these systems, in which the allosteric features are manifest by the effect of the first binding event on a similar event at the second site, the most informative state is the asymmetric singly bound (lig1) form, yet it tends to be thermodynamically elusive. Here we obtain milligram quantities of lig1 of the allosteric homodimer, chorismate mutase, in the form of a mixed isotopically labeled dimer stabilized by Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) between the subunits. Below, we outline several critical steps required to generate high yields of both types of unnatural amino acid-containing proteins and overcome multiple pitfalls intrinsic to CuAAC to obtain high yields of a highly purified, fully intact, active mixed labeled dimer, which provides the first glimpse of the lig1 intermediate. These data not only will make possible NMR-based investigations of allostery envisioned by us but also should facilitate other structural applications in which specific linkage of proteins is helpful.
Asunto(s)
Cobre/química , Compuestos Organometálicos/química , Alquinos/química , Sitio Alostérico , Azidas/química , Catálisis , Reacción de Cicloadición , Dimerización , Espectroscopía de Resonancia Magnética , Unión Proteica , TermodinámicaRESUMEN
Lung squamous carcinoma (LUSC) is a highly metastatic disease with a poor prognosis. Using an integrated screening approach, we found that miR-671-5p reduces LUSC metastasis by inhibiting a circular RNA (circRNA), CDR1as. Although the putative function of circRNA is through miRNA sponging, we found that miR-671-5p more potently silenced an axis of CDR1as and its antisense transcript, cerebellar degeneration related protein 1 (CDR1). Silencing of CDR1as or CDR1 significantly inhibited LUSC metastases and CDR1 was sufficient to promote migration and metastases. CDR1, which directly interacted with adaptor protein 1 (AP1) complex subunits and coatomer protein I (COPI) proteins, no longer promoted migration upon blockade of Golgi trafficking. Therapeutic inhibition of the CDR1as/CDR1 axis with miR-671-5p mimics reduced metastasis in vivo. This report demonstrates a novel role for CDR1 in promoting metastasis and Golgi trafficking. These findings reveal an miRNA/circRNA axis that regulates LUSC metastases through a previously unstudied protein, CDR1. SIGNIFICANCE: This study shows that circRNA, CDR1as, promotes lung squamous migration, metastasis, and Golgi trafficking through its complimentary transcript, CDR1.
Asunto(s)
Autoantígenos/metabolismo , Carcinoma de Células Escamosas/secundario , Aparato de Golgi/metabolismo , Neoplasias Pulmonares/patología , Proteínas del Tejido Nervioso/metabolismo , ARN Circular/antagonistas & inhibidores , ARN Largo no Codificante/metabolismo , Complejo 1 de Proteína Adaptadora/metabolismo , Animales , Autoantígenos/genética , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/mortalidad , Línea Celular Tumoral , Movimiento Celular/fisiología , Proteína Coat de Complejo I/metabolismo , Retículo Endoplásmico/metabolismo , Femenino , Humanos , Ácido Hialurónico/uso terapéutico , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/mortalidad , Ratones , Ratones Desnudos , MicroARNs/metabolismo , Nanopartículas/uso terapéutico , Metástasis de la Neoplasia , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Proteínas del Tejido Nervioso/genéticaRESUMEN
The NF-E2-related factor 2 (referred to as NRF2) transcription factor binds antioxidant responsive elements within the promoters of cytoprotective genes to induce their expression. Next-generation sequencing studies in lung cancer have shown a significant number of activating mutations within the NRF2 signaling pathway. Mutations in components of the SWI/SNF chromatin-remodeling complex, a general regulator of transcription using either BRG1 or BRM as the catalytic subunit, also frequently occur in lung cancers. Importantly, low BRG1 expression levels in primary human NSCLC correlated with increased NRF2-target gene expression. Here, we show that loss of SWI/SNF complex function activated a subset of NRF2-mediated transcriptional targets. Using a series of isogenic NSCLC lines with reduced or depleted BRG1 and/or BRM expression, we observed significantly increased expression of the NRF2-target genes HMOX1 and GSTM4. In contrast, expression of the NRF2 target genes NQO1 and GCLM modestly increased following BRM reduction. Chromatin immunoprecipitation showed that BRG1 knockdown led to increased NRF2 binding at its respective ARE sites in the HMOX1 promoter but not in NQO1 and GCLM. Our data demonstrate that loss of BRG1 or BRM in lung cancer results in activation of the NRF2/KEAP1 pathway and HMOX1 expression. Therefore, we provide an additional molecular explanation for why patients harboring BRG1 or BRM mutations show poor prognoses. A better understanding of this mechanism may yield novel insights into the design of targeted treatment modalities. IMPLICATIONS: Our study identifies a novel mechanism for how mutations in the SMARCA4 gene may drive progression of human lung adenocarcinomas.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/genética , ADN Helicasas/genética , Neoplasias Pulmonares/genética , Proteínas Nucleares/genética , Análisis de Secuencia de ADN/métodos , Transducción de Señal , Factores de Transcripción/genética , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Línea Celular Tumoral , Ensamble y Desensamble de Cromatina , Regulación Neoplásica de la Expresión Génica , Glutamato-Cisteína Ligasa/genética , Glutatión Transferasa/genética , Hemo-Oxigenasa 1/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Proteína 1 Asociada A ECH Tipo Kelch/genética , Mutación , NAD(P)H Deshidrogenasa (Quinona)/genética , Factor 2 Relacionado con NF-E2/genética , Factor 2 Relacionado con NF-E2/metabolismoRESUMEN
Activation of the nuclear factor (erythroid-derived 2)-like 2 (NFE2L2 or NRF2) transcription factor is a critical and evolutionarily conserved cellular response to oxidative stress, metabolic stress, and xenobiotic insult. Deficiency of NRF2 results in hypersensitivity to a variety of stressors, whereas its aberrant activation contributes to several cancer types, most commonly squamous cell carcinomas of the esophagus, oral cavity, bladder, and lung. Between 10% and 35% of patients with squamous cell carcinomas display hyperactive NRF2 signaling, harboring activating mutations and copy number amplifications of the NFE2L2 oncogene or inactivating mutations or deletions of KEAP1 or CUL3, the proteins of which co-complex to ubiquitylate and degrade NRF2 protein. To better understand the role of NRF2 in tumorigenesis and more broadly in development, we engineered the endogenous Nfe2l2 genomic locus to create a conditional mutant LSL-Nrf2E79Q mouse model. The E79Q mutation, one of the most commonly observed NRF2-activating mutations in human squamous cancers, codes for a mutant protein that does not undergo KEAP1/CUL3-dependent degradation, resulting in its constitutive activity. Expression of NRF2 E79Q protein in keratin 14 (KRT14)-positive murine tissues resulted in hyperplasia of squamous cell tissues of the tongue, forestomach, and esophagus, a stunted body axis, decreased weight, and decreased visceral adipose depots. RNA-seq profiling and follow-up validation studies of cultured NRF2E79Q murine esophageal epithelial cells revealed known and novel NRF2-regulated transcriptional programs, including genes associated with squamous cell carcinoma (e.g. Myc), lipid and cellular metabolism (Hk2, Ppard), and growth factors (Areg, Bmp6, Vegfa). These data suggest that in addition to decreasing adipogenesis, KRT14-restricted NRF2 activation drives hyperplasia of the esophagus, forestomach, and tongue, but not formation of squamous cell carcinoma. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Asunto(s)
Tejido Adiposo Blanco/patología , Carcinogénesis/genética , Modelos Animales de Enfermedad , Factor 2 Relacionado con NF-E2/genética , Lesiones Precancerosas/genética , Tracto Gastrointestinal Superior/patología , Animales , Carcinoma de Células Escamosas/genética , Esófago/patología , Humanos , Hiperplasia/genética , Ratones , Mutación , Lengua/patologíaRESUMEN
Nuclear proteins bind chromatin to execute and regulate genome-templated processes. While studies of individual nucleosome interactions have suggested that an acidic patch on the nucleosome disk may be a common site for recruitment to chromatin, the pervasiveness of acidic patch binding and whether other nucleosome binding hot-spots exist remain unclear. Here, we use nucleosome affinity proteomics with a library of nucleosomes that disrupts all exposed histone surfaces to comprehensively assess how proteins recognize nucleosomes. We find that the acidic patch and two adjacent surfaces are the primary hot-spots for nucleosome disk interactions, whereas nearly half of the nucleosome disk participates only minimally in protein binding. Our screen defines nucleosome surface requirements of nearly 300 nucleosome interacting proteins implicated in diverse nuclear processes including transcription, DNA damage repair, cell cycle regulation and nuclear architecture. Building from our screen, we demonstrate that the Anaphase-Promoting Complex/Cyclosome directly engages the acidic patch, and we elucidate a redundant mechanism of acidic patch binding by nuclear pore protein ELYS. Overall, our interactome screen illuminates a highly competitive nucleosome binding hub and establishes universal principles of nucleosome recognition.
Asunto(s)
Nucleosomas/metabolismo , Proteínas/metabolismo , Ciclosoma-Complejo Promotor de la Anafase/metabolismo , Sitios de Unión , Cromatina/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Histonas/genética , Histonas/metabolismo , Humanos , Metafase , Mutación , Proteómica/métodos , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
It is increasingly clear that interindividual variability in human gut microbial composition contributes to differential drug responses. For example, gastrointestinal (GI) toxicity is not observed in all patients treated with the anticancer drug irinotecan, and it has been suggested that this variability is a result of differences in the types and levels of gut bacterial ß-glucuronidases (GUSs). GUS enzymes promote drug toxicity by hydrolyzing the inactive drug-glucuronide conjugate back to the active drug, which damages the GI epithelium. Proteomics-based identification of the exact GUS enzymes responsible for drug reactivation from the complexity of the human microbiota has not been accomplished, however. Here, we discover the specific bacterial GUS enzymes that generate SN-38, the active and toxic metabolite of irinotecan, from human fecal samples using a unique activity-based protein profiling (ABPP) platform. We identify and quantify gut bacterial GUS enzymes from human feces with an ABPP-enabled proteomics pipeline and then integrate this information with ex vivo kinetics to pinpoint the specific GUS enzymes responsible for SN-38 reactivation. Furthermore, the same approach also reveals the molecular basis for differential gut bacterial GUS inhibition observed between human fecal samples. Taken together, this work provides an unprecedented technical and bioinformatics pipeline to discover the microbial enzymes responsible for specific reactions from the complexity of human feces. Identifying such microbial enzymes may lead to precision biomarkers and novel drug targets to advance the promise of personalized medicine.