Pregnane X receptor (PXR) is a major transcriptional regulator of xenobiotic metabolism and transport pathways in the liver and intestines, which are critical for protecting organisms against potentially harmful xenobiotic and endobiotic compounds. Inadvertent activation of drug metabolism pathways through PXR is known to contribute to drug resistance, adverse drug-drug interactions, and drug toxicity in humans. In both humans and rodents, PXR has been implicated in non-alcoholic fatty liver disease, diabetes, obesity, inflammatory bowel disease, and cancer. Because of PXR's important functions, it has been a therapeutic target of interest for a long time. More recent mechanistic studies have shown that PXR is modulated by multiple PTMs. Herein we provide the first investigation of the role of acetylation in modulating PXR activity. Through LC-MS/MS analysis, we identified lysine 109 (K109) in the hinge as PXR's major acetylation site. Using various biochemical and cell-based assays, we show that PXR's acetylation status and transcriptional activity are modulated by E1A binding protein (p300) and sirtuin 1 (SIRT1). Based on analysis of acetylation site mutants, we found that acetylation at K109 represses PXR transcriptional activity. The mechanism involves loss of RXRα dimerization and reduced binding to cognate DNA response elements. This mechanism may represent a promising therapeutic target using modulators of PXR acetylation levels. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie.

• MeSH
• acetylace MeSH
• aktivace transkripce * MeSH
• buňky Hep G2 MeSH
• DNA chemie   metabolismus   MeSH
• Escherichia coli genetika   metabolismus   MeSH
• HEK293 buňky MeSH
• HeLa buňky MeSH
• klonování DNA MeSH
• lidé MeSH
• luciferasy genetika   metabolismus   MeSH
• lysin chemie   metabolismus   MeSH
• molekulární modely MeSH
• multimerizace proteinu MeSH
• mutageneze cílená MeSH
• posttranslační úpravy proteinů * MeSH
• rekombinantní proteiny chemie   genetika   metabolismus   MeSH
• reportérové geny MeSH
• responzivní elementy MeSH
• sekundární struktura proteinů MeSH
• sirtuin 1 genetika   metabolismus   MeSH
• steroidní receptory chemie   genetika   metabolismus   MeSH
• strukturní homologie proteinů MeSH
• transkripční faktory p300-CBP genetika   metabolismus   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

BACKGROUND: Anaplastic large cell lymphoma (ALCL) is an aggressive non-Hodgkin T cell lymphoma commonly driven by NPM-ALK. AP-1 transcription factors, cJUN and JUNb, act as downstream effectors of NPM-ALK and transcriptionally regulate PDGFRβ. Blocking PDGFRβ kinase activity with imatinib effectively reduces tumor burden and prolongs survival, although the downstream molecular mechanisms remain elusive. METHODS AND RESULTS: In a transgenic mouse model that mimics PDGFRβ-driven human ALCL in vivo, we identify PDGFRβ as a driver of aggressive tumor growth. Mechanistically, PDGFRβ induces the pro-survival factor Bcl-xL and the growth-enhancing cytokine IL-10 via STAT5 activation. CRISPR/Cas9 deletion of both STAT5 gene products, STAT5A and STAT5B, results in the significant impairment of cell viability compared to deletion of STAT5A, STAT5B or STAT3 alone. Moreover, combined blockade of STAT3/5 activity with a selective SH2 domain inhibitor, AC-4-130, effectively obstructs tumor development in vivo. CONCLUSIONS: We therefore propose PDGFRβ as a novel biomarker and introduce PDGFRβ-STAT3/5 signaling as an important axis in aggressive ALCL. Furthermore, we suggest that inhibition of PDGFRβ or STAT3/5 improve existing therapies for both previously untreated and relapsed/refractory ALK+ ALCL patients.

• MeSH
• anaplastická lymfomová kináza MeSH
• anaplastický velkobuněčný lymfom * genetika   patologie   MeSH
• fosforylace MeSH
• karcinogeneze metabolismus   MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• růstový faktor odvozený z trombocytů - receptor beta * metabolismus   farmakologie   MeSH
• signální transdukce MeSH
• transkripční faktor STAT3 * metabolismus   MeSH
• transkripční faktor STAT5 * genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Pancreatic ductal adenocarcinoma (PDAC) presents significant challenges for targeted clinical interventions due to prevalent KRAS mutations, rendering PDAC resistant to RAF and MEK inhibitors (RAFi and MEKi). In addition, responses to targeted therapies vary between patients. Here, we explored the differential sensitivities of PDAC cell lines to RAFi and MEKi and developed an isogenic pair comprising the most sensitive and resistant PDAC cells. To simulate patient- or tumor-specific variations, we constructed cell-line-specific mechanistic models based on protein expression profiling and differential properties of KRAS mutants. These models predicted synergy between two RAFi with different conformation specificity (type I1⁄2 and type II RAFi) in inhibiting phospho-ERK (ppERK) and reducing PDAC cell viability. This synergy was experimentally validated across all four studied PDAC cell lines. Our findings underscore the need for combination approaches to inhibit the ERK pathway in PDAC.

• MeSH
• duktální karcinom slinivky břišní * farmakoterapie   patologie   metabolismus   MeSH
• inhibitory proteinkinas * farmakologie   MeSH
• lidé MeSH
• MAP kinasový signální systém * účinky léků   MeSH
• nádorové buněčné linie MeSH
• nádory slinivky břišní * patologie   farmakoterapie   metabolismus   MeSH
• protoonkogenní proteiny p21(ras) metabolismus   genetika   MeSH
• raf kinasy metabolismus   antagonisté a inhibitory   MeSH
• synergismus léků MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Diffuse large B-cell lymphoma (DLBCL) is an aggressive disease that exhibits constitutive activation of phosphoinositide 3-kinase (PI3K) driven by chronic B-cell receptor signaling or PTEN deficiency. Since pan-PI3K inhibitors cause severe side effects, we investigated the anti-lymphoma efficacy of the specific PI3Kβ/δ inhibitor AZD8186. We identified a subset of DLBCL models within activated B-cell-like (ABC) and germinal center B-cell-like (GCB) DLBCL that were sensitive to AZD8186 treatment. On the molecular level, PI3Kβ/δ inhibition decreased the pro-survival NF-κB and AP-1 activity or led to downregulation of the oncogenic transcription factor MYC. In AZD8186-resistant models, we detected a feedback activation of the PI3K/AKT/mTOR pathway following PI3Kβ/δ inhibition, which limited AZD8186 efficacy. The combined treatment with AZD8186 and the mTOR inhibitor AZD2014 overcame resistance to PI3Kβ/δ inhibition and completely prevented outgrowth of lymphoma cells in vivo in cell line- and patient-derived xenograft mouse models. Collectively, our study reveals that subsets of DLBCLs are addicted to PI3Kβ/δ signaling and thus identifies a previously unappreciated role of the PI3Kβ isoform in DLBCL survival. Furthermore, our data demonstrate that combined targeting of PI3Kβ/δ and mTOR is effective in all major DLBCL subtypes supporting the evaluation of this strategy in a clinical trial setting.

• MeSH
• difúzní velkobuněčný B-lymfom * patologie   MeSH
• fosfatidylinositol-3-kinasy * metabolismus   MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• signální transdukce MeSH
• TOR serin-threoninkinasy metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• mutageneze MeSH
• oprava DNA MeSH
• poškození DNA MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• embryologie a teratologie
• genetika, lékařská genetika

Pathogenic gain-of-function variants in the genes encoding phosphoinositide 3-kinase δ (PI3Kδ) lead to accumulation of transitional B cells and senescent T cells, lymphadenopathy, and immune deficiency (activated PI3Kδ syndrome [APDS]). Knowing the genetic etiology of APDS afforded us the opportunity to explore PI3Kδ inhibition as a precision-medicine therapy. Here, we report in vitro and in vivo effects of inhibiting PI3Kδ in APDS. Treatment with leniolisib (CDZ173), a selective PI3Kδ inhibitor, caused dose-dependent suppression of PI3Kδ pathway hyperactivation (measured as phosphorylation of AKT/S6) in cell lines ectopically expressing APDS-causative p110δ variants and in T-cell blasts derived from patients. A clinical trial with 6 APDS patients was conducted as a 12-week, open-label, multisite, within-subject, dose-escalation study of oral leniolisib to assess safety, pharmacokinetics, and effects on lymphoproliferation and immune dysregulation. Oral leniolisib led to a dose-dependent reduction in PI3K/AKT pathway activity assessed ex vivo and improved immune dysregulation. We observed normalization of circulating transitional and naive B cells, reduction in PD-1+CD4+ and senescent CD57+CD4- T cells, and decreases in elevated serum immunoglobulin M and inflammatory markers including interferon γ, tumor necrosis factor, CXCL13, and CXCL10 with leniolisib therapy. After 12 weeks of treatment, all patients showed amelioration of lymphoproliferation with lymph node sizes and spleen volumes reduced by 39% (mean; range, 26%-57%) and 40% (mean; range, 13%-65%), respectively. Thus, leniolisib was well tolerated and improved laboratory and clinical parameters in APDS, supporting the specific inhibition of PI3Kδ as a promising new targeted therapy in APDS and other diseases characterized by overactivation of the PI3Kδ pathway. This trial was registered at www.clinicaltrials.gov as #NCT02435173.

• MeSH
• aktivace lymfocytů účinky léků   MeSH
• chemokiny krev   MeSH
• cílená molekulární terapie * MeSH
• demografie MeSH
• dítě MeSH
• fenotyp MeSH
• fosfatidylinositol-3-kinasy třídy I antagonisté a inhibitory   imunologie   metabolismus   MeSH
• imunoglobulin M krev   MeSH
• inhibitory proteinkinas farmakologie   MeSH
• kojenec MeSH
• krysa rodu rattus MeSH
• lidé MeSH
• lymfatické uzliny účinky léků   patologie   MeSH
• mutace genetika   MeSH
• předškolní dítě MeSH
• pyridiny farmakokinetika   farmakologie   MeSH
• pyrimidiny farmakokinetika   farmakologie   MeSH
• slezina účinky léků   patologie   MeSH
• syndromy imunologické nedostatečnosti farmakoterapie   enzymologie   imunologie   patologie   MeSH
• T-lymfocyty účinky léků   imunologie   MeSH
• TOR serin-threoninkinasy antagonisté a inhibitory   metabolismus   MeSH
• transfekce MeSH
• velikost orgánu MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• krysa rodu rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, N.I.H., Intramural MeSH

UNLABELLED: Comparing the gene expression profiles of metastatic and nonmetastatic cells has the power to reveal candidate metastasis-associated genes, whose involvement in metastasis can be experimentally tested. In this study, differentially expressed genes were explored in the v-src-transformed metastatic cell line PR9692 and its nonmetastatic subclone PR9692-E9. First, the contribution of homeodomain only protein X (HOPX) in metastasis formation and development was assessed. HOPX-specific knockdown decreased HOPX expression in the nonmetastatic subclone and displayed reduced cell motility in vitro. Critically, HOPX knockdown decreased the in vivo metastatic capacity in a syngeneic animal model system. Genomic analyses identified a cadre of genes affected by HOPX knockdown that intersected significantly with genes previously found to be differentially expressed in metastatic versus nonmetastatic cells. Furthermore, 232 genes were found in both screens with at least a two-fold change in gene expression, and a number of high-confidence targets were validated for differential expression. Importantly, significant changes were demonstrated in the protein expression level of three metastatic-associated genes (NCAM, FOXG1, and ITGA4), and knockdown of one of the identified HOPX-regulated metastatic genes, ITGA4, showed marked inhibition of cell motility and metastasis formation. These data demonstrate that HOPX is a metastasis-associated gene and that its knockdown decreases the metastatic activity of v-src-transformed cells through altered gene expression patterns. IMPLICATIONS: This study provides new mechanistic insight into a HOPX-regulated metastatic dissemination signature.

• MeSH
• buněčný cyklus MeSH
• down regulace MeSH
• experimentální sarkom genetika   patologie   sekundární   MeSH
• forkhead transkripční faktory genetika   metabolismus   MeSH
• genový knockdown MeSH
• geny src MeSH
• homeodoménové proteiny genetika   metabolismus   MeSH
• kur domácí MeSH
• metastázy nádorů genetika   MeSH
• molekuly buněčné adheze nervové genetika   metabolismus   MeSH
• nádorová transformace buněk genetika   MeSH
• nádorové buněčné linie MeSH
• pohyb buněk MeSH
• ptačí proteiny genetika   metabolismus   MeSH
• regulace genové exprese u nádorů MeSH
• sekvenční analýza hybridizací s uspořádaným souborem oligonukleotidů MeSH
• stanovení celkové genové exprese MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

MicroRNAs (miRNAs) are crucial components of homeostatic and developmental gene regulation. In turn, dysregulation of miRNA expression is a common feature of different types of cancer, which can be harnessed therapeutically. Here we identify miR-139-5p suppression across several cytogenetically defined acute myeloid leukemia (AML) subgroups. The promoter of mir-139 was transcriptionally silenced and could be reactivated by histone deacetylase inhibitors in a dose-dependent manner. Restoration of mir-139 expression in cell lines representing the major AML subgroups (t[8;21], inv[16], mixed lineage leukemia-rearranged and complex karyotype AML) caused cell cycle arrest and apoptosis in vitro and in xenograft mouse models in vivo. During normal hematopoiesis, mir-139 is exclusively expressed in terminally differentiated neutrophils and macrophages. Ectopic expression of mir-139 repressed proliferation of normal CD34(+)-hematopoietic stem and progenitor cells and perturbed myelomonocytic in vitro differentiation. Mechanistically, mir-139 exerts its effects by repressing the translation initiation factor EIF4G2, thereby reducing overall protein synthesis while specifically inducing the translation of cell cycle inhibitor p27(Kip1). Knockdown of EIF4G2 recapitulated the effects of mir-139, whereas restoring EIF4G2 expression rescued the mir-139 phenotype. Moreover, elevated miR-139-5p expression is associated with a favorable outcome in a cohort of 165 pediatric patients with AML. Thus, mir-139 acts as a global tumor suppressor-miR in AML by controlling protein translation. As AML cells are dependent on high protein synthesis rates controlling the expression of mir-139 constitutes a novel path for the treatment of AML.

• MeSH
• buněčná diferenciace genetika   MeSH
• eukaryotický iniciační faktor 4G biosyntéza   genetika   MeSH
• genový knockdown MeSH
• lidé MeSH
• mikro RNA biosyntéza   genetika   MeSH
• myeloidní leukemie genetika   patologie   MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• proliferace buněk genetika   MeSH
• proteosyntéza * MeSH
• regulace genové exprese u leukemie MeSH
• xenogenní modely - testy protinádorové aktivity MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: The Angiotensin-I converting enzyme (ACE) is one of the most important components of the renin-angiotensin-aldosterone system controlling blood pressure and renal functions. Inhibitors of ACE are first line therapeutics used in the treatment of hypertension and related cardiovascular diseases. Somatic ACE consists of two homologous catalytic domains, the C- and N-domains. Recent findings have shown that although both domains are highly homologous in structure, they may have different physiological functions. The C-domain is primarily involved in the control of blood pressure, in contrast to the N-domain that is engaged in the regulation of hematopoietic stem cell proliferation. The currently available ACE inhibitors have some adverse effects that can be attributed to the non-selective inhibition of both domains. In addition, specific Ndomain inhibitors have emerged as potential antifibrotic drugs. Therefore, ACE is still an important drug target for the development of novel domain-selective drugs not only for the cardiovascular system but also for other systems. OBJECTIVE: Detailed structural information about interactions in the protein-ligand complex is crucial for rational drug design. This review highlights the structural information available from crystallographic data which is essential for the development of domain selective inhibitors of ACE. METHODS: Over eighty crystal complexes of ACE are placed into the Protein Database. An overview of X-ray ACE complexes with various inhibitors in C- and N-domains and an analysis of their binding mode have given mechanistic explanation of the structural determinants of selective ligand binding. In addition, ACE domain selective inhibitors with dual modes of action in complexes with ACE are also discussed. CONCLUSION: Selectivity of ACE inhibitors for the N- and C-domain is controlled by subtle differences in the amino-acids forming the active site. Reported studies of crystal complexes of inhibitors in the C- and N-domains revealed that most selective inhibitors interact with non-conserved amino-acids between domains and have distinct interactions with the residues in the S2 and S2' subsites of the ACE catalytic site. Moreover, unusual binding of the second molecule of inhibitors in the binding cavity opens new possibilities of exploiting more distant regions of the catalytic center in structure-based design of novel drugs.

• MeSH
• angiotensin konvertující enzym chemie   metabolismus   MeSH
• inhibitory ACE chemie   metabolismus   MeSH
• katalytická doména MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• proteinové domény MeSH
• racionální návrh léčiv MeSH
• substrátová specifita MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

In the adult brain, the extracellular matrix (ECM) influences recovery after injury, susceptibility to mental disorders, and is in general a strong regulator of neuronal plasticity. The proteoglycan aggrecan is a core component of the condensed ECM structures termed perineuronal nets (PNNs), and the specific role of PNNs on neural plasticity remains elusive. Here, we genetically targeted the Acan gene encoding for aggrecan using a novel animal model. This allowed for conditional and targeted loss of aggrecan in vivo, which ablated the PNN structure and caused a shift in the population of parvalbumin-expressing inhibitory interneurons toward a high plasticity state. Selective deletion of the Acan gene in the visual cortex of male adult mice reinstated juvenile ocular dominance plasticity, which was mechanistically identical to critical period plasticity. Brain-wide targeting improved object recognition memory.SIGNIFICANCE STATEMENT The study provides the first direct evidence of aggrecan as the main functional constituent and orchestrator of perineuronal nets (PNNs), and that loss of PNNs by aggrecan removal induces a permanent state of critical period-like plasticity. Loss of aggrecan ablates the PNN structure, resulting in invoked juvenile plasticity in the visual cortex and enhanced object recognition memory.

• MeSH
• agrekany analýza   nedostatek   genetika   MeSH
• buněčné linie MeSH
• extracelulární matrix chemie   genetika   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši transgenní MeSH
• myši MeSH
• nervová síť chemie   metabolismus   MeSH
• neuroplasticita fyziologie   MeSH
• světelná stimulace metody   MeSH
• zrakové korové centrum chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH