• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• onkologie
• nefrologie
• urologie

• Publikační typ
• souhrny MeSH

• Publikační typ
• abstrakt z konference MeSH

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a cytokine that can trigger apoptosis in many types of human cancer cells via engagement of its two pro-apoptotic receptors TRAIL-R1 (DR4) and TRAIL-R2 (DR5). TRAIL can also activate several other signaling pathways such as activation of stress kinases, canonical NF-κB signaling and necroptosis. Though both receptors are ubiquitously expressed, their relative participation in TRAIL-induced signaling is still largely unknown. To analyze TRAIL receptor-specific signaling, we prepared Strep-tagged, trimerized variants of recombinant human TRAIL with high affinity for either DR4 or DR5 receptor. Using these receptor-specific ligands, we examined the contribution of individual pro-apoptotic receptors to TRAIL-induced signaling pathways. We found that in TRAIL-resistant colorectal HT-29 cells but not in pancreatic PANC-1 cancer cells, DISC formation and initial caspase-8 processing proceeds comparably via both DR4- and DR5-activated signaling. TRAIL-induced apoptosis, enhanced by the inhibitor of the Bcl-2 family ABT-737, or by the translation inhibitor homoharringtonine, proceeded in both cell lines predominantly via the DR5 receptor. ShRNA-mediated downregulation of DR4 or DR5 receptors in HT-29 cells also pointed to a stronger contribution of DR5 in TRAIL-induced apoptosis. In contrast to apoptosis, necroptotic signaling was activated similarly by both DR4- or DR5-specific ligands. Activation of auxiliary signaling pathways involving NF-κB or stress kinases proceeded under apoptotic conditions mainly in a DR5-dependent manner, while these signaling pathways were during necroptosis similarly activated by either of these ligands. Our study provides the first systematic insight into DR4-/DR5-specific signaling in colorectal and pancreatic cancer cells.

• MeSH
• apoptóza genetika   MeSH
• buňky HT-29 MeSH
• kaspasa 8 genetika   MeSH
• kolorektální nádory genetika   patologie   MeSH
• lidé MeSH
• malá interferující RNA MeSH
• nádory slinivky břišní genetika   patologie   MeSH
• nekróza genetika   patologie   MeSH
• NF-kappa B genetika   MeSH
• pankreas metabolismus   patologie   MeSH
• proliferace buněk genetika   MeSH
• protein TRAIL genetika   MeSH
• regulace genové exprese u nádorů MeSH
• signální transdukce genetika   MeSH
• TRAIL receptory genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Tumour necrosis factor (TNF) related apoptosis inducing ligand (TRAIL), a membrane-bound ligand from the TNF family, has attracted significant attention due to its rather specific and effective ability to induce apoptotic death in various types of cancer cells via binding to and activating its pro-apoptotic death receptors. However, a significant number of primary cancer cells often develop resistance to TRAIL treatment, and the signalling platform behind this phenomenon is not fully understood. Upon blocking endosomal acidification by the vacuolar ATPase (V-ATPase) inhibitors bafilomycin A1 (BafA1) or concanamycin A, we observed a significantly reduced initial sensitivity of several, mainly colorectal, tumour cell lines to TRAIL-induced apoptosis. In cells pretreated with these inhibitors, the TRAIL-induced processing of caspase-8 and the aggregation and trafficking of the TRAIL receptor complexes were temporarily attenuated. Nuclear factor κB or mitogen activated protein/stress kinase signalling from the activated TRAIL receptors remained unchanged, and neither possible lysosomal permeabilization nor acid sphingomyelinase was involved in this process. The cell surface expression of TRAIL receptors and their TRAIL-induced internalization were not affected by V-ATPase inhibitors. The inhibitory effect of BafA1, however, was blunted by knockdown of the caspase-8 inhibitor cFLIP. Altogether, the data obtained provide the first evidence that endosomal acidification could represent an important regulatory node in the proximal part of TRAIL-induced pro-apoptotic signalling.

• MeSH
• aktivace enzymů MeSH
• apoptóza MeSH
• down regulace MeSH
• endozomy metabolismus   MeSH
• FLIP (buněčný) metabolismus   MeSH
• kaspasa 8 metabolismus   MeSH
• koncentrace vodíkových iontů MeSH
• lidé MeSH
• makrolidy farmakologie   MeSH
• nádorové buněčné linie MeSH
• protein TRAIL farmakologie   MeSH
• protinádorové látky farmakologie   MeSH
• sfingolipidy fyziologie   MeSH
• sfingomyelinfosfodiesterasa metabolismus   MeSH
• signální adaptorové proteiny receptorové domény smrti metabolismus   MeSH
• signální transdukce účinky léků   MeSH
• TRAIL receptory metabolismus   MeSH
• transport proteinů MeSH
• vakuolární protonové ATPasy antagonisté a inhibitory   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

One of perspective approaches in treatment of hematological malignancies is activation of death receptors for TRAIL. However, leukemia cells studied to date have shown variable susceptibility to TRAIL. Our study demonstrates that cells of acute T-lymphoblastic leukemia MOLT-4 are resistant to TRAIL and that ionizing radiation in the therapeutically achievable dose of 1 Gy sensitizes TRAIL-resistant cells MOLT-4 to the TRAIL-induced apoptosis by increase in death receptors for TRAIL DR5. When TRAIL is applied after the irradiation in the time of increased DR5 positivity more efficient cell killing is achieved.

• MeSH
• apoptóza účinky záření   účinky záření   MeSH
• leukemie metabolismus   patologie   MeSH
• lidé MeSH
• nádorové buňky kultivované účinky léků   účinky záření   MeSH
• protein TRAIL farmakologie   MeSH
• tolerance záření účinky léků   MeSH
• TRAIL receptory metabolismus   MeSH
• záření gama MeSH
• Check Tag
• lidé MeSH

Death ligands and their tumor necrosis factor receptor (TNFR) family receptors are the best-characterized and most efficient inducers of apoptotic signaling in somatic cells. In this study, we analyzed whether these prototypic activators of apoptosis are also expressed and able to be activated in human pluripotent stem cells. We examined human embryonic stem cells (hESC) and human-induced pluripotent stem cells (hiPSC) and found that both cell types express primarily TNF-related apoptosis-inducing ligand (TRAIL) receptors and TNFR1, but very low levels of Fas/CD95. We also found that although hESC and hiPSC contain all the proteins required for efficient induction and progression of extrinsic apoptotic signaling, they are resistant to TRAIL-induced apoptosis. However, both hESC and hiPSC can be sensitized to TRAIL-induced apoptosis by co-treatment with protein synthesis inhibitors such as the anti-leukemia drug homoharringtonine (HHT). HHT treatment led to suppression of cellular FLICE inhibitory protein (cFLIP) and Mcl-1 expression and, in combination with TRAIL, enhanced processing of caspase-8 and full activation of caspase-3. cFLIP likely represents an important regulatory node, as its shRNA-mediated down-regulation significantly sensitized hESC to TRAIL-induced apoptosis. Thus, we provide the first evidence that, irrespective of their origin, human pluripotent stem cells express canonical components of the extrinsic apoptotic system and on stress can activate death receptor-mediated apoptosis.

• MeSH
• antigeny CD95 genetika   metabolismus   MeSH
• apoptóza účinky léků   MeSH
• buněčná diferenciace MeSH
• embryonální kmenové buňky cytologie   účinky léků   metabolismus   MeSH
• FLIP (buněčný) antagonisté a inhibitory   genetika   metabolismus   MeSH
• harringtoniny farmakologie   MeSH
• inhibitory syntézy proteinů farmakologie   MeSH
• kaspasa 3 genetika   metabolismus   MeSH
• kaspasa 8 genetika   metabolismus   MeSH
• lidé MeSH
• malá interferující RNA genetika   metabolismus   MeSH
• pluripotentní kmenové buňky cytologie   účinky léků   metabolismus   MeSH
• proliferace buněk MeSH
• protein MCL-1 genetika   metabolismus   MeSH
• protein TRAIL genetika   metabolismus   farmakologie   MeSH
• receptory TNF - typ I genetika   metabolismus   MeSH
• regulace genové exprese MeSH
• signální transdukce MeSH
• synergismus léků MeSH
• TRAIL receptory genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

TNF-related apoptosis-inducing ligand (TRAIL) is a proapoptotic cytokine implicated in cancer cell surveillance. A potential of TRAIL as a cancer-specific therapeutic agent has been proposed, either as a single agent or in combination with chemotherapy. Prolonged exposure of TRAIL-sensitive leukemia cell line, wild-type (WT) HL60 cells to recombinant soluble TRAIL or to cytostatic agents, cytarabine and idarubicin, resulted in the establishment of resistant subclones with distinct phenotypic features. The TRAIL resistant HL60 subclones were characterized by decreased expression of TRAIL and TNFalpha death receptors. These resistant subclones had impaired activation of caspases 8 and 10 in response to TRAIL and TNFalpha, decreased TRAIL-induced nuclear translocation of NFkappaB RelA/p65, and dysregulation of the expression of several apoptosis regulators. Among the TRAIL resistant HL60 subclones we identified two separate phenotypes that differed in the expression of CD14, osteoprotegerin, and several apoptosis regulators. Both these TRAIL resistant HL60 subclones were resistant to TNFalpha, suggesting disruption of the extrinsic apoptotic pathway, but not to cytostatic agents, cytarabine and idarubicin. The concurrently derived HL60 subclones were cytarabine and idarubicin-resistant but remained sensitive to TRAIL-induced apoptosis. We identified distinct pathways for the development of HL60 leukemia cell resistance to apoptosis induction. These findings are relevant for the design of more effective strategies for leukemia therapy.

• MeSH
• akutní promyelocytární leukemie metabolismus   patologie   MeSH
• apoptóza MeSH
• chemorezistence MeSH
• cytarabin farmakologie   MeSH
• financování organizované MeSH
• HL-60 buňky MeSH
• idarubicin farmakologie   MeSH
• kaspasy metabolismus   účinky léků   MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• protein TRAIL farmakologie   MeSH
• protein-serin-threoninkinasy metabolismus   účinky léků   MeSH
• proteiny regulující apoptózu metabolismus   účinky léků   MeSH
• receptory TNF metabolismus   účinky léků   MeSH
• rekombinantní proteiny farmakologie   MeSH
• TNF-alfa farmakologie   MeSH
• TRAIL receptory metabolismus   účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH

Mantle cell lymphoma (MCL) is a rare aggressive type of B-cell non-Hodgkin's lymphoma. Response to chemotherapy tends to be short and virtually all patients sooner or later relapse. The prognosis of relapsed patients is extremely poor. The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is considered one of the novel experimental molecules with strong antitumor effects. TRAIL triggers extrinsic apoptotis in tumor cells by binding to TRAIL 'death receptors' on the cell surface. Recombinant TRAIL has shown promising pro-apoptotic effects in a variety of malignancies including lymphoma. However, as with other drugs, lymphoma cells can develop resistance to TRAIL. Therefore, the aim of this study was to identify the molecular mechanisms responsible for, and associated with TRAIL resistance in MCL cells. If identified, these features may be used as molecular targets for the effective elimination of TRAIL-resistant lymphoma cells. From an established TRAIL-sensitive mantle cell lymphoma cell line (HBL-2) we derived a TRAIL-resistant HBL-2/R subclone. By TRAIL receptor analysis and differential proteomic analysis of HBL-2 and HBL-2/R cells we revealed a marked downregulation of all TRAIL receptors and, among others, the decreased expression of 3 key enzymes of purine nucleotide metabolism, namely purine nucleoside phosphorylase, adenine phosphoribosyltransferase and inosine-5'-monophosphate dehydrogenase 2, in the resistant HBL-2/R cells. The downregulation of the 3 key enzymes of purine metabolism can have profound effects on nucleotide homeostasis in TRAIL-resistant lymphoma cells and can render such cells vulnerable to any further disruption of purine nucleotide metabolism. This pathway represents a 'weakness' of the TRAIL-resistant MCL cells and has potential as a therapeutic target for the selective elimination of such cells.

• MeSH
• 2D gelová elektroforéza MeSH
• buněčná membrána metabolismus   MeSH
• buněčná smrt účinky léků   MeSH
• chemorezistence účinky léků   MeSH
• lidé MeSH
• lymfom z plášťových buněk enzymologie   patologie   MeSH
• nádorové buněčné linie MeSH
• nádorové proteiny metabolismus   MeSH
• protein TRAIL farmakologie   MeSH
• proteomika MeSH
• průtoková cytometrie MeSH
• puriny metabolismus   MeSH
• reprodukovatelnost výsledků MeSH
• TRAIL receptory metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Disruption of apoptotic pathways belongs to commonly reported molecular mechanisms that underlie cancer drug resistance. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL, Apo2L) is a cytokine of the TNF family with selective anti-tumor activity and minimal toxicity toward healthy tissues. Primary leukemia cells are, however, largely intrinsically resistant to TRAIL-induced apoptosis. In this study we analyzed molecular differences between TRAIL-resistant K562 cell line and TRAIL-sensitive K562 clones. We demonstrate that TRAIL-sensitive K562 cells differ from the TRAIL-resistant cell line by cell surface downregulation of TRAIL decoy receptor 1, upregulation of both TRAIL death receptors, enhanced assembly and improved functioning of the death-inducing signaling complex, and increased cytoplasmic protein expression of CASP8 and key proapoptotic BCL2 members BID, BIM, BAD and BAK. The molecular basis of the intrinsic leukemia cell TRAIL resistance thus appears a consequence of the multi-level disruption of the extrinsic apoptotic pathway. The results of this study also suggest that the leukemia TRAIL-resistance is functional, leaving a possibility of overcoming the resistance by preexposure of the leukemia cells to potent TRAIL sensitizers, e.g. BH3-mimetics.

• MeSH
• apoptóza * MeSH
• buňky K562 MeSH
• chemorezistence MeSH
• lidé MeSH
• protein TRAIL farmakologie   MeSH
• signální transdukce MeSH
• TNF-alfa farmakologie   MeSH
• TRAIL receptory analýza   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH