RESUMO
The interleukin 6 (IL6)/glycoprotein 130 (GP130)/signal transducer and activator of transcription 3 (STAT3) signalling pathway, with GP130 as an intermediate membrane receptor, is involved in the survival, metastasis, and resistance of ovarian cancer. Bazedoxifene, an FDAapproved drug, is an inhibitor of GP130 and a selective estrogen modulator (SERM). We studied the mechanism of the combination therapy of bazedoxifene and paclitaxel in inhibiting the IL6mediated GP130/STAT3 signaling pathway in ovarian cancer. Surface plasmon resonance (SPR) was used to assess the binding of bazedoxifene to GP130. Migration, invasion, and apoptosis of ovarian cancer cells were assessed using bazedoxifene and paclitaxel. In addition, we determined the effects of bazedoxifene and paclitaxel alone or in combination on the GP130/STAT3 pathway and epithelialmesenchymal transition (EMT). The results revealed that the combination of bazedoxifene and paclitaxel suppressed cell viability, migration, and invasion in the ovarian cancer cells. In addition, the combination treatment increased apoptosis. Furthermore, bazedoxifene combined with paclitaxel inhibited the growth of ovarian cancer cells in a xenograft tumour model. This combination reduced STAT3 phosphorylation and suppressed gene expression and EMT. In conclusion, inhibition of GP130/STAT3 signalling and EMT via a combination of bazedoxifene and paclitaxel could be used as a therapeutic strategy by which to overcome ovarian cancer.
Assuntos
Receptor gp130 de Citocina/efeitos dos fármacos , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Indóis/farmacologia , Neoplasias Ovarianas/tratamento farmacológico , Paclitaxel/farmacologia , Fator de Transcrição STAT3/efeitos dos fármacos , Animais , Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Quimioterapia Combinada , Feminino , Glicoproteínas/efeitos dos fármacos , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Moduladores Seletivos de Receptor Estrogênico/farmacologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
OBJECTIVE: Human adult articular cartilage (AC) has little capacity for repair, and joint surface injuries often result in osteoarthritis (OA), characterised by loss of matrix, hypertrophy and chondrocyte apoptosis. Inflammation mediated by interleukin (IL)-6 family cytokines has been identified as a critical driver of proarthritic changes in mouse and human joints, resulting in a feed-forward process driving expression of matrix degrading enzymes and IL-6 itself. Here we show that signalling through glycoprotein 130 (gp130), the common receptor for IL-6 family cytokines, can have both context-specific and cytokine-specific effects on articular chondrocytes and that a small molecule gp130 modulator can bias signalling towards anti-inflammatory and antidegenerative outputs. METHODS: High throughput screening of 170 000 compounds identified a small molecule gp130 modulator termed regulator of cartilage growth and differentiation (RCGD 423) that promotes atypical homodimeric signalling in the absence of cytokine ligands, driving transient increases in MYC and pSTAT3 while suppressing oncostatin M- and IL-6-mediated activation of ERK and NF-κB via direct competition for gp130 occupancy. RESULTS: This small molecule increased proliferation while reducing apoptosis and hypertrophic responses in adult chondrocytes in vitro. In a rat partial meniscectomy model, RCGD 423 greatly reduced chondrocyte hypertrophy, loss and degeneration while increasing chondrocyte proliferation beyond that observed in response to injury. Moreover, RCGD 423 improved cartilage healing in a rat full-thickness osteochondral defect model, increasing proliferation of mesenchymal cells in the defect and also inhibiting breakdown of cartilage matrix in de novo generated cartilage. CONCLUSION: These results identify a novel strategy for AC remediation via small molecule-mediated modulation of gp130 signalling.
Assuntos
Doenças das Cartilagens/tratamento farmacológico , Cartilagem Articular/metabolismo , Receptor gp130 de Citocina/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Animais , Proliferação de Células/efeitos dos fármacos , Condrócitos/metabolismo , Modelos Animais de Doenças , Genes myc/efeitos dos fármacos , Ratos , Fator de Transcrição STAT3/metabolismoRESUMO
INTRODUCTION: Ubiquitously expressed in the human body, glycoprotein 130 (gp130) is a shared subunit of receptor complexes for at least nine cytokines (IL-6, OSM, LIF, IL-11, CNTF, CLC, IL-27, CT-1, and NP) that mediate highly diverse biological processes. Dysregulation of gp130 expression, activation, or associated signaling pathways are implicated in a variety of human diseases, including cancer. Accumulating evidence indicates that the gp130-mediated signaling networks play important roles in the progression of multiple types of cancer. AREAS COVERED: This review discusses the structural basis of gp130 in signal transduction activity and its role in physiological and pathological conditions, particularly cancer. We analyzed the currently available databases to illustrate the expression of gp130, its coexpression with other molecules involved in the gp130 signaling pathways, and the role of gp130 in cancer progression. Finally, we highlight strategies for blocking gp130 signaling and the currently available antagonists. EXPERT OPINION: As gp130 signaling mediates cancer progression, inhibition of gp130 activity offers a potential and promising approach to cancer therapy. Compared to antibodies blocking individual cytokines, gp130-targeted small-molecule inhibitors present multiple advantages. To achieve successful clinical outcomes for gp130-targeted cancer therapy, dosage determination, duration of therapy, and patient selection are some of the critical factors to be considered.
Assuntos
Receptor gp130 de Citocina/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Receptor gp130 de Citocina/química , Receptor gp130 de Citocina/metabolismo , Humanos , Neoplasias/metabolismo , Conformação Proteica , Transdução de SinaisRESUMO
Glioblastomas are the most common and most lethal primary brain tumor. Recent studies implicate an important role for a restricted population of neoplastic cells (glioma stem cells (GSCs)) in glioma maintenance and recurrence. We now demonstrate that GSCs preferentially express two interleukin 6 (IL6) receptors: IL6 receptor alpha (IL6R alpha) and glycoprotein 130 (gp130). Targeting IL6R alpha or IL6 ligand expression in GSCs with the use of short hairpin RNAs (shRNAs) significantly reduces growth and neurosphere formation capacity while increasing apoptosis. Perturbation of IL6 signaling in GSCs attenuates signal transducers and activators of transcription three (STAT3) activation, and small molecule inhibitors of STAT3 potently induce GSC apoptosis. These data indicate that STAT3 is a downstream mediator of prosurvival IL6 signals in GSCs. Targeting of IL6R alpha or IL6 expression in GSCs increases the survival of mice bearing intracranial human glioma xenografts. IL6 is clinically significant because elevated IL6 ligand and receptor expression are associated with poor glioma patient survival. The potential utility of anti-IL6 therapies is demonstrated by decreased growth of subcutaneous human GSC-derived xenografts treated with IL6 antibody. Together, our data indicate that IL6 signaling contributes to glioma malignancy through the promotion of GSC growth and survival, and that targeting IL6 may offer benefit for glioma patients.
Assuntos
Neoplasias Encefálicas/tratamento farmacológico , Glioma/tratamento farmacológico , Interleucina-6/antagonistas & inibidores , Células-Tronco Neoplásicas/efeitos dos fármacos , Animais , Apoptose/genética , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/imunologia , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Sobrevivência Celular/imunologia , Receptor gp130 de Citocina/efeitos dos fármacos , Receptor gp130 de Citocina/genética , Receptor gp130 de Citocina/metabolismo , Glioma/genética , Glioma/imunologia , Sobrevivência de Enxerto/efeitos dos fármacos , Sobrevivência de Enxerto/fisiologia , Inibidores do Crescimento/farmacologia , Humanos , Interleucina-6/metabolismo , Camundongos , Camundongos Nus , Células-Tronco Neoplásicas/imunologia , Células-Tronco Neoplásicas/metabolismo , Interferência de RNA/fisiologia , RNA Interferente Pequeno/farmacologia , Receptores de Interleucina-6/efeitos dos fármacos , Receptores de Interleucina-6/genética , Receptores de Interleucina-6/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Transplante Heterólogo , Células Tumorais CultivadasRESUMO
Members of the interleukin-6 cytokine family, including leukemia inhibitory factor (LIF), signal through gp130. The neuroprotective role of gp130 activation has been widely demonstrated in both CNS and PNS, but the mechanism by which this is accomplished is not well established. We investigated temporal and cell-specific activation of signaling pathways induced by LIF in the mature mouse retina. Intravitreal injection of LIF preserved photoreceptor function and prevented photoreceptor cell death from light-induced oxidative damage in a dose-dependent manner (2 days post-injection). A therapeutic dose of LIF induced rapid and sustained activation of signal transducer and activator of transcription (STAT) 3. Activated STAT3 was localized to all the retinal neurons and glial cells, including photoreceptors. Activation of extracellular signal-regulated kinase 1 and 2 was robust but transient in Müller glial cells, and undetectable at the time of light exposure. Akt was not activated by LIF. We also show that at the time of neuroprotection, STAT3 but not extracellular signal-regulated kinase 1 and 2 or the Akt pathways was active in LIF-treated retinas, and activated STAT3 was clearly localized in transcriptionally active areas of photoreceptor nuclei. Our data suggest that photoreceptor protection in response to LIF can be directly mediated by activation of STAT3 in photoreceptors.
Assuntos
Citoproteção/fisiologia , Fator Inibidor de Leucemia/metabolismo , Luz/efeitos adversos , Células Fotorreceptoras/metabolismo , Células Fotorreceptoras/efeitos da radiação , Fator de Transcrição STAT3/metabolismo , Animais , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Receptor gp130 de Citocina/efeitos dos fármacos , Receptor gp130 de Citocina/metabolismo , Citoproteção/efeitos dos fármacos , Relação Dose-Resposta a Droga , MAP Quinases Reguladas por Sinal Extracelular/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Fator Inibidor de Leucemia/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Neuroglia/efeitos dos fármacos , Neuroglia/metabolismo , Fármacos Neuroprotetores/metabolismo , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Células Fotorreceptoras/efeitos dos fármacos , Fator de Transcrição STAT3/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Fatores de Tempo , Ativação Transcricional/efeitos dos fármacos , Ativação Transcricional/fisiologiaRESUMO
Interleukin-6 (IL-6) is a major regulator of the acute phase reaction in the liver and is thought to mediate protective effects in response to hepatotoxins. In this study, the influence of bile acids on IL-6 signal transduction was analyzed. It was shown that hydrophobic bile acids such as glycochenodeoxycholate (GCDC) inhibited IL-6-induced tyrosine phosphorylation of signal transducer and activator of transcription (STAT) 3 in hepatocytes and in perfused rat liver. This inhibition was accompanied by GCDC-mediated downregulation of glycoprotein (gp) 130 expression, whereas gp130 and suppressor of cytokine signaling 3 messenger RNA and gp80 protein levels remained unaffected. The GCDC-induced downregulation of gp130 protein expression was insensitive to inhibition of proteasomal or lysosomal protein degradation but turned out to be sensitive to inhibition of caspase-3 or caspase-8 activity. Accordingly, treatment of cell extracts with active recombinant caspase-3 led to a decay of immunoreactive gp130. Moreover, activation of caspases by CD95 ligand or hyperosmotic stress also resulted in a downregulation of gp130 levels. This indicates that caspase activation antagonizes IL-6 signaling by decay of gp130 levels. However, caspase inhibition did not prevent GCDC-dependent inhibition of IL-6-induced STAT3 activation, which turned out to be at least partially sensitive to suppression of p38(MAPK) activation. In conclusion, hydrophobic bile acids compromise IL-6 signaling through both a caspase-mediated downregulation of gp130 and a p38(MAPK)-dependent inhibition of STAT3 phosphorylation. This may contribute to bile acid-induced hepatotoxicity in cholestasis through counteracting the known hepatoprotective effects of IL-6.
Assuntos
Ácidos e Sais Biliares/metabolismo , Receptor gp130 de Citocina/metabolismo , Hepatócitos/metabolismo , Interleucina-6/antagonistas & inibidores , Fígado/metabolismo , Transdução de Sinais/fisiologia , Animais , Inibidores de Caspase , Caspases/metabolismo , Linhagem Celular , Células Cultivadas , Receptor gp130 de Citocina/efeitos dos fármacos , Regulação para Baixo , Ácido Glicoquenodesoxicólico/farmacologia , Interleucina-6/fisiologia , Masculino , Transportadores de Ânions Orgânicos Dependentes de Sódio/antagonistas & inibidores , Fosforilação , Ratos , Ratos Wistar , Fator de Transcrição STAT3 , Transdução de Sinais/efeitos dos fármacos , Simportadores/antagonistas & inibidoresRESUMO
In recent years, the elucidation of the structures of many signalling molecules has allowed new insights into the molecular mechanisms that govern signal transduction events. In the field of cytokine signalling, the solved structures of cytokine/receptor complexes and of key components involved in signal transduction such as STAT factors or the tyrosine phosphatase SHP2 have broadened our understanding of the molecular basis of the signalling events and provided key information for the rational design of therapeutic approaches to modulate or block cytokine signal transduction. Unfortunately, no structural data on the intracellular parts of cytokine receptors are available. The exact molecular mechanism underlying one of the first steps in signal transduction, namely the recruitment of signalling components to the cytoplasmic parts of cytokine receptors, remains elusive. Here we investigated possible mechanisms underlying the different potency of the STAT3-activating motifs of gp130 after IL-6 stimulation. Our data indicate that the extent of STAT3 activation by the different receptor motifs is not influenced by structural features such as contacts between the two gp130 chains. In addition, the proximity of the negatively regulating motif around tyrosine Y759 to the different STAT3-recruiting motifs does not seem to be responsible for their differential capacity to activate STAT3. However, the potency of a specific motif to activate STAT3 directly reflects the affinity for the binding of STAT3 to this motif.