Úvod: Technika susceptibilitně vážených MR obrazů (SWI) se stala vhodným nástrojem k detekci mikro krvácení (MK) a také sledování změn signálu V bazálních gangliích. Tyto změny signálu jsou přisuzovány zvýšené koncentraci železa, ale mohou být také způsobeny kalcifikacemi nebo starším krvácením. V této studii bylo SWI použito k detekci MK a signálových změn v nucleus caudatus (NC), putamen (PUT) a globus palidus (GP) u pacientů s Alzheimerovou chorobou (AD) a mild cognitive impairement (MCI). Material a metody: Celkem bylo zhodnoceno 47 subjektů, z toho bylo 19 pacientů s AD, 16 pacientů s MCI a 12 zdravých subjektů. Vyšetření byla realizována na MR systému Siemens Trio Tim 3T a měření SWI bylo provedeno s následujícími parametry sekvence: TR = 33 ms, TE = 20 ms, sklápěcí úhel = 15°, velikost voxelu 0,6 x 0,6 x 0,8 mm, čas měření 5:20 min. Byl hodnocen relativní signál v NC, PUT a GP a v celém zobrazeném objemu mozku zaznamenán počet jednotlivých MK. Změny signálu v BG a počet MK byly korelovány s údajem MMSE. Výsledky: Z vyšetřených subjektů se alespoň 1 leze MK nalezla u 29 subjektů (62 %), více než 4 leze u 8 subjektů (17 %). U pacientů s AD se MK vyskytovaly ve vyšší míře (v průměru 1,89 leze na pacienta) než u MCI (1,38 leze na pacienta) a kontrol (0,41 leze na pacienta). Tyto rozdíly však nebyly signifikantní. Nejvyšší pokles signálu ve strukturách BG s efektem susceptibility byl zaznamenán u některých subjektů v GP, menší pak v PUT, naopak změny V NC prakticky nebyly. I v tomto případě je častější výskyt poklesu signálu u pacientů, lze ho však najít i u řady zdravých kontrol. Závěr: Oba studované jevy pomocí SWI představují jiný aspekt možného příspěvku k progresu demence typu AD (vaskulární příspěvek a de¬ gradace tkáně v BG). Změny na SWI mohou přispět do celkového morfologického skóre pacienta a vysvětlit příčinu v některých případech.

Introduction: Recently, the new technique of susceptibility weighted imaging (SWI) has become suitable tool to detect micro-bleeding (MB) an d also to follow MR signal changes in basal ganglia (BG). These signal changes are supposed to be closely connected to iron depos ition increase but they also could be caused by calcification or older hemorrhage. In this study, SWI was used to detect MB and to measure sig nal in nucleus caudatus (NC), putamen (PUT) and globus palidus in patients with Alzheimer disease (AD) and mild cognitive impairment (MCI). Material and methods: We examined 47 subjects: 19 AD patients, 16 MCI patients and 12 healthy age matched volunteers. All examinations were done on Siemens Trio 3T MR system using SWI sequence with following parameters: TR = 33 ms, TE = 20 ms, flip angle = 15°, voxel size of 0,6 × 0,6 × 0,8 mm, measurement time 5:20 min. Relative signal in NC, PUT and GP was evaluated and number of MB in entire brain vol ume was calculated. Signal changes in BG were correlated with MMSE. Results: At least one MB lesion was found in 29 subjects (62 %) and more then 4 lesions in 8 subjects (17 %). In AD patients group, MB lesions were found more frequently (1.89 lesions per subject in average) then in MCI group (1.38 lesions per subject) and control group (0.41 lesions per subject). However, these differences were not significant. The most significant signal decrease was found in GP in some subjects but almost no change of signal intensity in NC was detect ed. Also in this case, more often the low signal in GP was found in AD group but we could see this effect also in more healthy subjects. Conclusions: Both effects studied using SWI represent different aspects of possible contribution to the progression of the dementia of the AD type (vascular contribution and tissue degradation in BG). Evaluated changes in SWI can provide valuable information into the e ntire charac- terization of the clinical state of AD patients and also explain some cases.

• Klíčová slova
• Alzheimerova choroba, MR zobrazování, susceptibilitně vážené zobrazování,
• MeSH
• Alzheimerova nemoc diagnóza   MeSH
• financování organizované MeSH
• kognitivní poruchy diagnóza   MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   přístrojové vybavení   MeSH
• nucleus caudatus patologie   MeSH
• putamen patologie   MeSH
• senioři MeSH
• Check Tag
• lidé MeSH
• senioři MeSH

Chromatin structure and its changes or maintenance throughout developmental checkpoints play indispensable role in organismal homeostasis. Chromatin remodeling factors of the SWI/SNF2 superfamily use ATP hydrolysis to change DNA-protein contacts, and their loss-of-function or inappropriate increase leads to distinct human pathologic states. In this review, we focus on the translational view of human pathologic physiology involving SWI/SNF2 superfamily, combining latest finding from basic and clinical research. We discuss in mechanistic terms the consequences resulting from dose alteration of the SWI/SNF2 superfamily ATPases and emphasize the necessity of future human subject-based studies.

• MeSH
• chromatin metabolismus   MeSH
• chromozomální proteiny, nehistonové metabolismus   MeSH
• DNA nádorová metabolismus   MeSH
• DNA-helikasy genetika   metabolismus   MeSH
• DNA metabolismus   MeSH
• financování organizované MeSH
• genetické nemoci vrozené genetika   metabolismus   MeSH
• histony metabolismus   MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• leukemie genetika   metabolismus   MeSH
• lidé MeSH
• nádory genetika   metabolismus   MeSH
• transkripční faktory genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• přehledy MeSH

Loss of the SWI/SNF chromatin remodeling complex has been recently implicated in the pathogenesis of dedifferentiated carcinomas from different organs, but its possible role in undifferentiated urothelial carcinoma (UC) has not been studied to date. In this study, we analyzed by immunohistochemistry 14 undifferentiated UCs (11 from bladder and 3 from renal pelvis) with a nondescript anaplastic or rhabdoid morphology, using commercially available antibodies against the SWI/SNF components SMARCB1 (INI1), SMARCA2, SMARCA4, SMARCC1, SMARCC2, and ARID1A. Patients were eight females and six males aged 40 to 84 years (median, 65). All tumors were muscle-invasive (9 were T3-4). A conventional UC component was seen in eight cases and varied from in situ to papillary. The undifferentiated component comprised 60-100 % of the tumors. Histologically, most tumors showed diffuse dyscohesive or pseudoalveolar growth of variably sized cells with frequent rhabdoid features. Transition from conventional to undifferentiated UC was abrupt, except in one case. The undifferentiated component almost always expressed pan-cytokeratin AE1/AE3 (13/14) and variably vimentin (8/14) and GATA3 (9/14). Complete loss of at least one SWI/SNF subunit limited to the undifferentiated component was detected in 10/14 cases (71 %). SMARCA2 was most frequently lost (six) followed by ARID1A (four), SMARCB1/INI1 (two), SMARCA4 (one), and SMARCC1 (one). This is the first study exploring SWI/SNF expression in undifferentiated UC of the urinary tract. Our results are in line with recent studies reporting involvement of the SWI/SNF complex in the dedifferentiation process of a variety of epithelial neoplasms in different organs, including the urinary tract, and association with aggressive clinical course.

• MeSH
• DNA-helikasy metabolismus   MeSH
• dospělí MeSH
• gen SMARCB1 metabolismus   MeSH
• imunohistochemie metody   MeSH
• jaderné proteiny metabolismus   MeSH
• karcinom z přechodných buněk metabolismus   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• močové ústrojí metabolismus   patologie   MeSH
• rhabdoidní nádor diagnóza   metabolismus   patologie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• transkripční faktory metabolismus   MeSH
• urologické nádory diagnóza   metabolismus   patologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Chromatin remodelers are complexes able to both alter histone-DNA interactions and to mobilize nucleosomes. The mechanism of their action and the conformation of remodeled nucleosomes remain a matter of debates. In this work we compared the type and structure of the products of nucleosome remodeling by SWI/SNF and ACF complexes using high-resolution microscopy combined with novel biochemical approaches. We find that SWI/SNF generates a multitude of nucleosome-like metastable particles termed "remosomes". Restriction enzyme accessibility assay, DNase I footprinting and AFM experiments reveal perturbed histone-DNA interactions within these particles. Electron cryo-microscopy shows that remosomes adopt a variety of different structures with variable irregular DNA path, similar to those described upon RSC remodeling. Remosome DNA accessibility to restriction enzymes is also markedly increased. We suggest that the generation of remosomes is a common feature of the SWI/SNF family remodelers. In contrast, the ACF remodeler, belonging to ISWI family, only produces repositioned nucleosomes and no evidence for particles associated with extra DNA, or perturbed DNA paths was found. The remosome generation by the SWI/SNF type of remodelers may represent a novel mechanism involved in processes where nucleosomal DNA accessibility is required, such as DNA repair or transcription regulation.

• MeSH
• adenosintrifosfát metabolismus   farmakologie   MeSH
• bezbuněčný systém MeSH
• chromozomální proteiny, nehistonové fyziologie   MeSH
• DNA bakterií metabolismus   MeSH
• DNA footprinting MeSH
• fungální proteiny fyziologie   MeSH
• histony genetika   metabolismus   MeSH
• mikroskopie atomárních sil MeSH
• multiproteinové komplexy fyziologie   MeSH
• nukleozomy fyziologie   ultrastruktura   MeSH
• plazmidy chemie   MeSH
• proteiny vázající RNA fyziologie   MeSH
• rekombinantní proteiny metabolismus   MeSH
• restrikční endonukleasy typu II MeSH
• restrukturace chromatinu genetika   fyziologie   MeSH
• Saccharomyces cerevisiae metabolismus   ultrastruktura   MeSH
• Xenopus laevis genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Chordoma is a rare malignant tumor with notochordal differentiation, usually affecting the axial skeleton of young patients. We report a case of a high-grade epithelioid tumor involving the synovium and soft tissues of the knee in a 74-year-old male patient. The preliminary biopsy was inconclusive, but a diagnosis of metastatic clear-cell carcinoma of unknown origin was suggested. However, imaging studies did not reveal any primary lesions. The resection specimen consisted of nests and sheets of oval to polygonal cells with discernible cell borders, clear or lightly amphophilic cytoplasm, and round to oval nuclei with occasional well-visible eosinophilic nucleoli. Rare atypical mitoses, necrotic areas, and bizarre nuclei were noted. The biopsy and resection specimens underwent a wide molecular genetic analysis which included methylation profiling. The DKFZ sarcoma classifier assigned the methylation class chordoma (dedifferentiated) with a calibrated score of 0.96, and additionally, a loss of SMARCB1 locus was noted in the copy number variation plot. To verify these findings, T-brachyury and SMARCB1 immunostaining was performed afterward, showing diffuse nuclear positivity and complete loss in the tumor cells, respectively. To assess the prevalence of T-brachyury immunopositivity among SWI/SNF-deficient tumors and to evaluate its specificity for poorly differentiated chordoma, we analyzed a series of 23 SMARCB1- or SMARCA4-deficient tumors, all of which were negative. After incorporating all the available data, including the absence of any morphological features of conventional chordoma, the case was diagnosed as poorly differentiated chordoma. As illustrated herein, the utilization of methylation profiling in the diagnostic process of some carefully selected unclassifiable soft tissue neoplasms may lead to an increased detection rate of such extremely rare soft tissue tumors and enable their better characterization.

• MeSH
• buněčná diferenciace MeSH
• chordom * patologie   genetika   diagnóza   metabolismus   MeSH
• fetální proteiny * genetika   metabolismus   MeSH
• gen SMARCB1 * genetika   MeSH
• lidé MeSH
• metylace DNA * MeSH
• nádorové biomarkery * analýza   genetika   MeSH
• nádory měkkých tkání patologie   diagnóza   genetika   metabolismus   MeSH
• proteiny T-boxu * genetika   metabolismus   MeSH
• senioři MeSH
• transkripční faktory genetika   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

Metastasized malignant melanoma has a poor prognosis because of its intrinsic resistance to chemotherapy and radiotherapy. The central role in the melanoma transcriptional network has the transcription factor MITF (microphthalmia-associated transcription factor). It has been shown recently that the expression of MITF and some of its target genes require the SWI/SNF chromatin remodeling complex. Here we demonstrate that survival of melanoma cells requires functional SWI/SNF complex not only by supporting expression of MITF and its targets and but also by activating expression of prosurvival proteins not directly regulated by MITF. Microarray analysis revealed that besides the MITF-driven genes, expression of proteins like osteopontin, IGF1, TGFß2 and survivin, the factors known to be generally associated with progression of tumors and the antiapoptotic properties, were reduced in acute BRG1-depleted 501mel cells. Western blots and RT-PCR confirmed the microarray findings. These proteins have been verified to be expressed independently of MITF, because MITF depletion did not impair their expression. Because these genes are not regulated by MITF, the data suggests that loss of BRG1-based SWI/SNF complexes negatively affects survival pathways beyond the MITF cascade. Immunohistochemistry showed high expression of both BRM and BRG1 in primary melanomas. Exogenous CDK2, osteopontin, or IGF1 each alone partly relieved the block of proliferation imposed by BRG1 depletion, implicating that more factors, besides the MITF target genes, are involved in melanoma cell survival. Together these results demonstrate an essential role of SWI/SNF for the expression of MITF-dependent and MITF-independent prosurvival factors in melanoma cells and suggest that SWI/SNF may be a potential and effective target in melanoma therapy.

• MeSH
• apoptóza genetika   MeSH
• chromozomální proteiny, nehistonové genetika   metabolismus   MeSH
• cyklin-dependentní kinasa 2 genetika   metabolismus   MeSH
• DNA-helikasy genetika   metabolismus   MeSH
• imunohistochemie MeSH
• inhibitory apoptózy genetika   metabolismus   MeSH
• insulinu podobný růstový faktor I genetika   metabolismus   MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• lidé MeSH
• melanom genetika   metabolismus   patologie   MeSH
• nádorové buněčné linie MeSH
• névus genetika   metabolismus   patologie   MeSH
• osteopontin genetika   metabolismus   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• proliferace buněk MeSH
• RNA interference MeSH
• sekvenční analýza hybridizací s uspořádaným souborem oligonukleotidů MeSH
• stanovení celkové genové exprese MeSH
• transformující růstový faktor beta2 genetika   metabolismus   MeSH
• transkripční faktor spojený s mikroftalmií genetika   metabolismus   MeSH
• transkripční faktory genetika   metabolismus   MeSH
• viabilita buněk genetika   MeSH
• western blotting MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Multiproteinový chromatin-remodelující komplex SWI/SNF je považován za nádorový supresor a jeho funkce je u několika typů nádorových buněk porušena tím, že některé jeho složky (Brm, Brg1 a INI1) jsou deletovány nebo mutovány. Bude zkoumána exprese komponent komplexu v buňkách malobuněčného (SCLC) i nemalobuněčného (NSCLC) karcinomu plic a maligního melanomu a vztah exprese k nádorové progresi. Dále bude zkoumána úloha tohoto komplexu při transkripci genů a markerů spojených s diferenciací melanomových buněk. Výsledky ukáží na možnou úlohu porušeného komplexu při patogenezi těchto nádorů zejména ve vztahu k invazivitě a metastasování a pomohou při prognose nádorového onemocnění.; The SWI/SNF chromatin-remodeling complex functions as a tumor suppressor and several of its subunits (Brm, Brg1 a INI1) were found to be mutated in human tumors. We propose to study the expression of the SWI/SNF components in non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC) and melanoma, and to investigate the role of an abrogated function of SWI/SNF in the progression of these three specific tumor types. We will further study how SWI/SNF participates in the differentiation program of melanoma cells. The results will indicate how the altered function or loss of subunits contribute to malignant behavior of the selected types of tumors with respect to invasion and formation of metastases.

• MeSH
• exprese genu MeSH
• genetická transkripce MeSH
• malobuněčný karcinom plic MeSH
• melanom MeSH
• metastázy nádorů MeSH
• nádorové procesy MeSH
• nemalobuněčný karcinom plic MeSH
• prognóza MeSH
• restrukturace chromatinu MeSH
• transformované buněčné linie MeSH

• Konspekt
• Biochemie. Molekulární biologie. Biofyzika
• NLK Obory
• onkologie
• biologie
• NLK Publikační typ
• závěrečné zprávy o řešení grantu IGA MZ ČR

UNLABELLED: In acute myeloid leukemia (AML), SWI/SNF chromatin remodeling complexes sustain leukemic identity by driving high levels of MYC. Previous studies have implicated the hematopoietic transcription factor PU.1 (SPI1) as an important target of SWI/SNF inhibition, but PU.1 is widely regarded to have pioneer-like activity. As a result, many questions have remained regarding the interplay between PU.1 and SWI/SNF in AML as well as normal hematopoiesis. Here we found that PU.1 binds to most of its targets in a SWI/SNF-independent manner and recruits SWI/SNF to promote accessibility for other AML core regulatory factors, including RUNX1, LMO2, and MEIS1. SWI/SNF inhibition in AML cells reduced DNA accessibility and binding of these factors at PU.1 sites and redistributed PU.1 to promoters. Analysis of nontumor hematopoietic cells revealed that similar effects also impair PU.1-dependent B-cell and monocyte populations. Nevertheless, SWI/SNF inhibition induced profound therapeutic response in an immunocompetent AML mouse model as well as in primary human AML samples. In vivo, SWI/SNF inhibition promoted leukemic differentiation and reduced the leukemic stem cell burden in bone marrow but also induced leukopenia. These results reveal a variable therapeutic window for SWI/SNF blockade in AML and highlight important off-tumor effects of such therapies in immunocompetent settings. SIGNIFICANCE: Disruption of PU.1-directed enhancer programs upon SWI/SNF inhibition causes differentiation of AML cells and induces leukopenia of PU.1-dependent B cells and monocytes, revealing the on- and off-tumor effects of SWI/SNF blockade.

• MeSH
• akutní myeloidní leukemie * farmakoterapie   genetika   metabolismus   MeSH
• buněčná diferenciace MeSH
• kostní dřeň patologie   MeSH
• leukopenie * genetika   MeSH
• lidé MeSH
• myši MeSH
• promotorové oblasti (genetika) MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

The microphthalmia-associated transcription factor (MITF) is required for melanocyte development, maintenance of the melanocyte-specific transcription, and survival of melanoma cells. MITF positively regulates expression of more than 25 genes in pigment cells. Recently, it has been demonstrated that expression of several MITF downstream targets requires the SWI/SNF chromatin remodeling complex, which contains one of the two catalytic subunits, Brm or Brg1. Here we show that the expression of MITF itself critically requires active SWI/SNF. In several Brm/Brg1-expressing melanoma cell lines, knockdown of Brg1 severely compromised MITF expression with a concomitant downregulation of MITF targets and decreased cell proliferation. Although Brm was able to substitute for Brg1 in maintaining MITF expression and melanoma cell proliferation, sequential knockdown of both Brm and Brg1 in 501mel cells abolished proliferation. In Brg1-null SK-MEL-5 melanoma cells, depletion of Brm alone was sufficient to abrogate MITF expression and cell proliferation. Chromatin immunoprecipitation confirmed the binding of Brg1 or Brm to the promoter of MITF. Together these results demonstrate the essential role of SWI/SNF for expression of MITF and suggest that SWI/SNF may be a promissing target in melanoma therapy.

• MeSH
• aktivace transkripce MeSH
• chromozomální proteiny, nehistonové metabolismus   MeSH
• DNA-helikasy metabolismus   MeSH
• imunoprecipitace MeSH
• jaderné proteiny metabolismus   MeSH
• lidé MeSH
• melanom genetika   MeSH
• nádorové buněčné linie MeSH
• promotorové oblasti (genetika) MeSH
• regulace genové exprese u nádorů MeSH
• restrukturace chromatinu MeSH
• transkripční faktor spojený s mikroftalmií genetika   MeSH
• transkripční faktory genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

Fumarate hydratase-deficient renal cell carcinoma (FH-RCC) is a rare, aggressive RCC type, originally described in the setting of hereditary leiomyomatosis and RCC syndrome, which is defined by germline FH gene inactivation. Inactivation of components of the switch/sucrose nonfermentable (SWI/SNF) chromatin remodeling complex is involved in renal medullary carcinoma (SMARCB1/INI1 loss), clear cell RCC (PBRM1 loss), and subsets of dedifferentiated RCC of clear cell, chromophobe, and papillary types (loss of different SWI/SNF components). FH-RCC and SWI/SNF-deficient RCC share anaplastic nuclear features and highly aggressive course. We analyzed 32 FH-RCCs from 28 patients using 7 commercially available SWI/SNF antibodies (SMARCB1/INI1, SMARCA2, SMARCA4, SMARCC1, SMARCC2, PBRM1, and ARID1A). Variable loss of SMARCB1, ARID1A, and SMARCC1 was observed in 1 of 31, 2 of 31, and 1 of 29 evaluable cases, respectively; 3 of these 4 SWI/SNF-deficient tumors had confirmed FH mutations. No correlation of SWI/SNF loss with solid or sarcomatoid features was observed. Two tumors with SMARCB1 and ARID1A deficiency had available SWI/SNF molecular data; both lacked SMARCB1 and ARID1A mutations. The remaining 5 SWI/SNF components were intact in all cases. Especially PBRM1 seems not to be involved in the pathogenesis or progression of FH-RCC. Our data showed that a subset of FH-RCC (12%) have a variable loss of SWI/SNF complex subunits, likely as secondary genetic events. This should not be confused with SWI/SNF-deficient RCC of other types. Evaluation of FH and SWI/SNF together with comprehensive molecular genetic profiling is needed to explore possible prognostic implications of FH/SWI-SNF double deficiency and to better understand the somatic mutation landscape in high-grade RCC.

• MeSH
• chromozomální proteiny, nehistonové metabolismus   MeSH
• DNA-helikasy genetika   metabolismus   MeSH
• dospělí MeSH
• fumarasa nedostatek   MeSH
• imunohistochemie metody   MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• karcinom z renálních buněk genetika   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mutace genetika   MeSH
• nádory ledvin genetika   patologie   MeSH
• senioři MeSH
• transkripční faktory genetika   metabolismus   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH