The inhibitor of apoptosis proteins (IAPs) are best known for their ability to regulate cell survival and death processes. However, in addition to cell death, IAPs also act as innate immune sensors and modulate multiple pathways, such as autophagy and cell division. Many of these IAP functions are non-redundant even though they are based on the same molecular mechanism of action. These distinct functions of IAPs derive from their capacity to target specific substrates for ubiquitination and/or proteolytic cleavage. The unique functions of IAPs also derives from their unique cellular localizations, cell type and tissue-specific expression patterns. The diverse roles of IAPs are reflected by the fact that in humans the IAP family comprises eight distinct members. Genetic evidence from human pathologies also attests to the non-redundant functions of the IAPs since very diverse diseases arise upon aberrant IAP expression. In this review, we give an overview of the known mechanisms of action of the various IAPs, and focus on their specific roles in mediating innate immunity. We also look at the distinct phenotypes related to the dysregulation of the IAPs, and the human pathologies associated with each human IAP.
- MeSH
- autoimunitní nemoci imunologie patologie MeSH
- buněčná smrt MeSH
- infekce imunologie patologie MeSH
- inflamasomy imunologie MeSH
- inhibitory apoptózy genetika imunologie MeSH
- lidé MeSH
- signální transdukce MeSH
- viabilita buněk * MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Survivin, an important antiapoptotic protein, is expressed in tumors, whereas in normal tissues the expression of this protein is extremely low, defining a role for survivin as a cancer gene. Survivin exhibits multifunctional activity in tumor cells. However, why survivin expression is sharply and invariably restricted to tumor tissue remains unclear. Here, we identified 11 putative consensus binding sites for GLI transcription factors in the survivin promoter and characterized the promoter activity. Inhibitors of the Hedgehog/GLI pathway, cyclopamine and GANT61, decreased the promoter activity in reporter assays. ΔNGLI2 (which lacks the repressor domain) was the most potent vector in activating the survivin promoter-reporter. Moreover, GANT61, a GLI1/2 inhibitor, repressed endogenous survivin protein and mRNA expression in most cells across a large panel of tumor cell lines. Chromatin immunoprecipitation showed GLI2 binding to the survivin promoter. The ectopic GLI2-evoked expression of endogenous survivin was observed in normal human fibroblasts. GANT61 decreased survivin level in nude mice tumors, mimicking the activity of GANT61 in cultured cells. The immunohistochemistry and double immunofluorescence of human tumors revealed a correlation between the tissue regions showing high GLI2 and survivin positivity. Thus, these results demonstrated that survivin is a classical transcriptional target of GLI2, a Hedgehog pathway signaling effector. This potentially reflects the high expression of survivin in human tumor cells. As the Hedgehog pathway is upregulated in virtually all types of cancer cells, these findings substantially contribute to the explanation of uniform survivin expression in tumors as a potential target for the development of a more effective treatment of cancers through the inhibition of GLI2 to restrain survivin activity.
- MeSH
- inhibitory apoptózy genetika metabolismus MeSH
- lidé MeSH
- myši nahé MeSH
- myši MeSH
- proteiny hedgehog metabolismus MeSH
- represorové proteiny genetika metabolismus MeSH
- signální transdukce MeSH
- transfekce MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Inhibition of apoptosis by the ligands of the aryl hydrocarbon receptor (AhR) has been proposed to play a role in their tumor promoting effects on liver parenchymal cells. However, little is presently known about the impact of toxic AhR ligands, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on apoptosis in other liver cell types, such as in liver epithelial/progenitor cells. In the present study, we focused on the effects of TCDD on apoptosis regulation in a model of liver progenitor cells, rat WB-F344 cell line, during the TCDD-elicited release from contact inhibition. The stimulation of cell proliferation in this cell line was associated with deregulated expression of a number of genes known to be under transcriptional control of the Hippo signaling pathway, a principal regulatory pathway involved in contact inhibition of cell proliferation. Interestingly, we found that mRNA and protein levels of survivin, a known Hippo target, which plays a role both in cell division and inhibition of apoptosis, were significantly up-regulated in rat liver epithelial cell model, as well as in undifferentiated human liver HepaRG cells. Using the short interfering RNA-mediated knockdown, we confirmed that survivin plays a central role in cell division of WB-F344 cells. When evaluating the effects of TCDD on apoptosis induction by camptothecin, a genotoxic topoisomerase I inhibitor, we observed that the pre-treatment of WB-F344 cells with TCDD increased number of cells with apoptotic nuclear morphology, and it potentiated cleavage of both caspase-3 and poly(ADP-ribose) polymerase I. This indicated that despite the observed up-regulation of survivin, apoptosis induced by the genotoxin was potentiated in the model of rat liver progenitor cells. The present results indicate that, unlike in hepatocytes, AhR agonists may not prevent induction of apoptosis elicited by DNA-damaging agents in a model of rat liver progenitor cells.
- MeSH
- apoptóza účinky léků MeSH
- buněčné linie MeSH
- časové faktory MeSH
- epitelové buňky účinky léků metabolismus patologie MeSH
- genetická transkripce účinky léků MeSH
- inhibitory apoptózy genetika metabolismus MeSH
- inhibitory topoisomerasy I toxicita MeSH
- játra účinky léků metabolismus patologie MeSH
- kamptothecin toxicita MeSH
- kaspasa 3 metabolismus MeSH
- kontaktní inhibice účinky léků MeSH
- lidé MeSH
- poly(ADP-ribosa)polymerasy metabolismus MeSH
- polychlorované dibenzodioxiny toxicita MeSH
- potkani inbrední F344 MeSH
- proteiny asociované s mikrotubuly genetika metabolismus MeSH
- receptory aromatických uhlovodíků agonisté metabolismus MeSH
- RNA interference MeSH
- signální transdukce účinky léků MeSH
- transfekce MeSH
- transkripční faktory bHLH agonisté metabolismus MeSH
- upregulace MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Deletion of the cellular inhibitor of apoptosis protein 2 (cIAP2) is capable of rendering lipopolysaccharide (LPS)-activated macrophages highly susceptible to apoptotic triggers, thereby quickly eliminating the resident macrophage population soon after the initiation of a systemic inflammatory response. The aim of our study was to evaluate the impact of cIAP2 deletion on leukocyte recruitment and capillary perfusion in experimental endotoxemia and polybacterial sepsis using intravital microscopy of the intestinal microcirculation, which is crucial in the pathogenesis of septic multiple organ failure. We studied six groups of animals: wild-type (WT) control mice, cIAP2 knockout mice, endotoxemic WT mice (5 mg/kg LPS), endotoxemic cIAP2 knockouts (5 or 50 mg/kg LPS, respectively), and WT as well as knockout mice with polybacterial sepsis (colon ascendens stent peritonitis [CASP]). Intravital microscopy of the intestinal microcirculation was performed after 1 h of endotoxemia or 12 h of CASP-induced sepsis, respectively. Intestinal microvascular blood flow was measured using laser Doppler flowmetry. After 1 h of endotoxemia (5 mg/kg LPS), we observed a significant increase of leukocyte adhesion in intestinal submucosal venules of WT mice in comparison with control animals. The cIAP2 knockout mice showed a significant reduction in leukocyte recruitment within the intestinal submucosal microvasculature after 5 or 50 mg/kg LPS challenge, respectively. Lipopolysaccharide-induced decrease in intestinal microvascular blood flow was not affected by cIAP2 inhibition. In CASP-induced sepsis, cIAP2 deletion had no effect on intestinal leukocyte recruitment. Deletion of cIAP2 resulted in reduced microvascular leukocyte recruitment within the intestinal microcirculation in endotoxemia but not in polybacterial sepsis.
- MeSH
- endotoxemie genetika metabolismus patofyziologie MeSH
- inhibitory apoptózy genetika metabolismus MeSH
- mikrocirkulace genetika fyziologie MeSH
- modely nemocí na zvířatech MeSH
- myši inbrední C57BL MeSH
- myši knockoutované MeSH
- myši MeSH
- sepse genetika metabolismus patofyziologie MeSH
- střeva krevní zásobení MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Recent studies have revealed recurrent mutations of the NOTCH1, SF3B1 and BIRC3 genes in chronic lymphocytic leukemia (CLL), especially among aggressive, chemorefractory cases. Nevertheless, it is currently unknown whether their presence may differ in subsets of patients carrying stereotyped B-cell receptors and also exhibiting distinct prognoses. Here, we analyzed the mutation status of NOTCH1, SF3B1 and BIRC3 in three subsets with particularly poor prognosis, that is, subset #1, #2 and #8, aiming to explore links between genetic aberrations and immune signaling. A remarkably higher frequency of SF3B1 mutations was revealed in subset #2 (44%) versus subset #1 and #8 (4.6% and 0%, respectively; P<0.001). In contrast, the frequency of NOTCH1 mutations in subset #2 was only 8%, lower than the frequency observed in either subset #1 or #8 (19% and 14%, respectively; P=0.04 for subset #1 versus #2). No associations were found for BIRC3 mutations that overall were rare. The apparent non-random association of certain mutations with stereotyped CLL subsets alludes to subset-biased acquisition of genomic aberrations, perhaps consistent with particular antigen/antibody interactions. These novel findings assist in unraveling specific mechanisms underlying clinical aggressiveness in poor-prognostic stereotyped subsets, with far-reaching implications for understanding their clonal evolution and implementing biologically oriented therapy.
- MeSH
- buněčný inhibitor apoptózy 2 MeSH
- chronická lymfatická leukemie * genetika klasifikace mortalita MeSH
- DNA nádorová genetika MeSH
- fosfoproteiny * genetika MeSH
- inhibitory apoptózy * genetika MeSH
- kohortové studie MeSH
- lidé MeSH
- malý jaderný ribonukleoprotein U2 * genetika MeSH
- míra přežití MeSH
- mutace * genetika MeSH
- nádorové biomarkery * genetika MeSH
- následné studie MeSH
- polymerázová řetězová reakce MeSH
- prognóza MeSH
- receptor Notch1 * genetika MeSH
- sestřihové faktory MeSH
- ubikvitinligasy MeSH
- Check Tag
- lidé 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
Cíl Neuroendokrinní nádory pankreatu (pancreatic neuroendocrine tumor, PNET), ač vzácné, často metastazují a chirurgická resekce, jediná potenciálně kurativní léčba, tak u nich není možná. Pro nemocné s pokročilými PNET není doposud k dispozici účinná systémová terapie. Z tohoto důvodu jsou potřebné nové léčebné strategie. S tímto cílem realizovali autoři výzkum s využitím preklinických myších modelů PNET, zaměřený na posouzení potenciálního prospěchu terapeutické duální inhibice kinázy receptoru pro epidermální růstový faktor (epidermal growth factor receptor, EGFR) a mTOR (mammalian target of rapamycin – savčí rapamycinový cílený receptor). Materiál a metody Transgenním myším RIP-Tag2 s pokročilými multifokálními PNET byl aplikován inhibitor mTOR rapamycin a inhibitor EGRF erlotinib. Monitorován byl nádorový růst a přežití a dále bylo prováděno vyšetření tumorózních tkání s cílem nalézt potenciální biomarkery odpovědi na podávanou terapii. Výsledky Monoterapie rapamycinem byla výrazně účinná, došlo k prodloužení přežití současně se stabilizací nádorového růstu (stabilní onemocnění). Nakonec však došlo k rozvoji rezistence nádorového onemocnění, což dokazovala progrese růstu tumoru. Monoterapie erlotinibem navodila zpomalení růstu a přinesla hraniční zlepšení přežití. Při použití kombinace obou látek bylo u tohoto agresivního multifokálního nádoru v porovnání s každou z monoterapií zaznamenáno nebývalé zlepšení přežití, přičemž nebyl patrný rozvoj adaptační rezistence. Kromě toho bylo zjištěno, že antiapoptotický protein survivin může sloužit jako biomarker senzitivity a příznivé odpovědi na cílenou duální inhibiční terapii. Závěr Preklinické studie na myších modelech endogenních PNET naznačují, že kombinovaná cílená blokáda signálních drah mTOR a EGFR by mohla přinášet v terapii PNET potenciální klinický prospěch. Uvedené výsledky povzbudily přípravu a realizaci klinické studie fáze II zaměřené na zhodnocení účinnosti tohoto terapeutického režimu u lidských neuroendokrinních nádorů.
- MeSH
- analýza přežití MeSH
- chinazoliny aplikace a dávkování farmakologie MeSH
- erbB receptory antagonisté a inhibitory metabolismus MeSH
- financování organizované MeSH
- imunohistochemie MeSH
- imunosupresiva aplikace a dávkování farmakologie MeSH
- inhibitory apoptózy genetika metabolismus MeSH
- inhibitory proteinkinas aplikace a dávkování farmakologie MeSH
- intracelulární signální peptidy a proteiny antagonisté a inhibitory metabolismus MeSH
- klinické zkoušky, fáze II jako téma MeSH
- lidé MeSH
- modely nemocí na zvířatech MeSH
- myši transgenní MeSH
- myši MeSH
- nádorové buněčné linie MeSH
- neuroendokrinní nádory farmakoterapie metabolismus patologie MeSH
- protein-serin-threoninkinasy antagonisté a inhibitory metabolismus MeSH
- proteiny regulující apoptózu metabolismus MeSH
- protokoly protinádorové kombinované chemoterapie terapeutické užití MeSH
- represorové proteiny antagonisté a inhibitory metabolismus MeSH
- RNA interference MeSH
- signální transdukce účinky léků MeSH
- sirolimus aplikace a dávkování farmakologie MeSH
- TOR serin-threoninkinasy MeSH
- viabilita buněk MeSH
- výsledek terapie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- MeSH
- apoptóza genetika imunologie účinky léků MeSH
- cyklin-dependentní kinasy genetika škodlivé účinky MeSH
- genetická transkripce genetika MeSH
- hematologické nádory etiologie krev patofyziologie MeSH
- inhibiční proteiny cyklin-dependentních kinas genetika škodlivé účinky MeSH
- inhibitory apoptózy analýza genetika MeSH
- lidé MeSH
- protein TRAIL genetika škodlivé účinky MeSH
- proteiny teplotního šoku genetika škodlivé účinky MeSH
- protinádorové látky terapeutické užití MeSH
- Check Tag
- lidé MeSH
- MeSH
- Caenorhabditis elegans cytologie genetika MeSH
- finanční podpora výzkumu jako téma MeSH
- genetická transkripce imunologie MeSH
- inhibitory apoptózy analýza genetika MeSH
- lidé MeSH
- mikročipová analýza metody využití MeSH
- polymerázová řetězová reakce s reverzní transkripcí metody využití MeSH
- RNA interference fyziologie MeSH
- savci genetika MeSH
- vývojová regulace genové exprese genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- srovnávací studie MeSH