RESUMO
Besides having high potency and efficacy at the µ- (MOR) and other opioid receptor types, fentanyl has some affinity for some adrenergic receptor types, which may underlie its unique pathophysiological differences from typical opioids. To better understand the unique actions of fentanyl, we assessed the extent to which fentanyl alters striatal medium spiny neuronal (MSNs) activity via opioid or α1 adrenoceptors in dopamine type 1 or type 2 receptor- (D1 or D2) -expressing MSNs. In neuronal and mixed-glial co-cultures from the striatum, acute fentanyl (100 nM) exposure decreased the frequency of spontaneous action potentials. Overnight exposure of co-cultures to 100 nM fentanyl severely reduced the proportion of MSNs with spontaneous action potentials, which was unaffected by co-exposure to the opioid receptor antagonist naloxone (10 µM), but fully negated by co-administering the pan-α1 adrenoceptor inverse agonist prazosin (100 nM) and partially reversed by the selective α1A/C adrenoceptor antagonist RS 100329 (300 nM). Acute fentanyl (100 nM) exposure modestly reduced the frequency of action potentials and caused firing rate adaptations in D2, but not D1, MSNs. Prolonged (2-5 h) fentanyl (100 nM) application dramatically attenuated firing rates in both D1 and D2 MSNs. To identify possible cellular sites of α1 adrenoceptor action, α1 adrenoceptors were localized in subpopulations of striatal astroglia and neurons by immunocytochemistry, and Adra1a mRNA by in situ hybridization in astrocytes. Thus, sustained fentanyl exposure can inhibit striatal MSN activity via a non-opioid receptor-dependent pathway, that may be modulated via complex actions in α1 adrenoceptor-expressing striatal neurons and/or glia.
RESUMO
Many persons infected with HIV-1 (PWH) and opioid-dependent individuals experience deficits in sociability that interfere with daily living. Sociability is regulated by the prefrontal cortico-hippocampal-amygdalar circuit. Within this circuit HIV-1 trans-activator of transcription (HIV-1 Tat) and opioids can increase dendritic pathology and alter neuronal firing. Changes in sociability are also associated with dysregulation of hypothalamic neuropeptides such as oxytocin or corticotropin releasing factor (CRF) in the prefrontal cortico-hippocampal-amygdalar circuit. Accordingly, we hypothesized that the interaction of HIV-1 Tat and morphine would impair inter-male social interactions and disrupt oxytocin and CRF within the PFC and associated circuitry. Male mice were exposed to HIV-1 Tat for 8 weeks and administered saline or escalating doses of morphine twice daily (s.c.) during the last 2 weeks of HIV-1 Tat exposure. Tat attenuated aggressive interactions with an unknown intruder, whereas morphine decreased both non-aggressive and aggressive social interactions in the resident-intruder test. However, there was no effect of Tat or morphine on non-reciprocal interactions in the social interaction and novelty tests. Tat, but not morphine, decreased oxytocin levels in the PFC and amygdala, whereas both Tat and morphine decreased the percentage of oxytocin-immunoreactive neurons in the hypothalamic paraventricular nucleus (PVN). In Tat(+) or morphine-exposed mice, regional levels of CRF and oxytocin correlated with alterations in behavior in the social interaction and novelty tests. Overall, decreased expression of oxytocin in the prefrontal cortico-hippocampal-amygdalar circuit is associated with morphine- and HIV-Tat-induced deficits in social behavior.
Assuntos
HIV-1 , Morfina , Tonsila do Cerebelo/metabolismo , Animais , Masculino , Camundongos , Morfina/farmacologia , Ocitocina , Núcleo Hipotalâmico Paraventricular/metabolismo , Córtex Pré-Frontal/metabolismo , Interação Social , Transativadores , Produtos do Gene tat do Vírus da Imunodeficiência HumanaRESUMO
Stromal components not only help form the structure of neoplasms such as melanomas, but they also functionally contribute to their malignant phenotype. Thus, uncovering signaling pathways that integrate the behavior of both tumor and stromal cells may provide unique opportunities for the development of more effective strategies to control tumor progression. In this regard, extracellular matrix-mediated signaling plays a role in coordinating the behavior of both tumor and stromal cells. Here, evidence is provided that targeting a cryptic region of the extracellular matrix protein collagen (HU177 epitope) inhibits melanoma tumor growth and metastasis and reduces angiogenesis and the accumulation of α-SMA-expressing stromal cell in these tumors. The current study suggests that the ability of the HU177 epitope to control melanoma cell migration and metastasis depends on the transcriptional coactivator Yes-associated protein (YAP). Melanoma cell interactions with the HU177 epitope promoted nuclear accumulation of YAP by a cyclin-dependent kinase-5-associated mechanism. These findings provide new insights into the mechanism by which the anti-HU177 antibody inhibits metastasis, and uncovers an unknown signaling pathway by which the HU177 epitope selectively reprograms melanoma cells by regulating nuclear localization of YAP. This study helps to define a potential new therapeutic strategy to control melanoma tumor growth and metastasis that might be used alone or in combination with other therapeutics.
Assuntos
Movimento Celular/efeitos dos fármacos , Colágeno/fisiologia , Epitopos/fisiologia , Melanoma/fisiopatologia , Neoplasias Cutâneas/fisiopatologia , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Inibidores da Angiogênese/farmacologia , Anticorpos Anti-Idiotípicos/farmacologia , Anticorpos Anti-Idiotípicos/fisiologia , Proliferação de Células/fisiologia , Colágeno/imunologia , Quinase 5 Dependente de Ciclina/antagonistas & inibidores , Quinase 5 Dependente de Ciclina/metabolismo , Humanos , Melanoma/patologia , Metástase Neoplásica , Neovascularização Patológica/imunologia , Fosfoproteínas/metabolismo , Fosforilação/fisiologia , Neoplasias Cutâneas/patologia , Células Estromais/fisiologia , Talina/metabolismo , Fatores de Transcrição , Células Tumorais Cultivadas , Proteínas de Sinalização YAPRESUMO
Extracellular matrix (ECM) remodeling regulates angiogenesis. However, the precise mechanisms by which structural changes in ECM proteins contribute to angiogenesis are not fully understood. Integrins are molecules with the ability to detect compositional and structural changes within the ECM and integrate this information into a network of signaling circuits that coordinate context-dependent cell behavior. The role of integrin αvß3 in angiogenesis is complex, as evidence exists for both positive and negative functions. The precise downstream signaling events initiated by αvß3 may depend on the molecular characteristics of its ligands. Here, we identified an RGD-containing cryptic collagen epitope that is generated in vivo. Surprisingly, rather than inhibiting αvß3 signaling, this collagen epitope promoted αvß3 activation and stimulated angiogenesis and inflammation. An antibody directed to this RGDKGE epitope but not other RGD collagen epitopes inhibited angiogenesis and inflammation in vivo. The selective ability of this RGD epitope to promote angiogenesis and inflammation depends in part on its flanking KGE motif. Interestingly, a subset of macrophages may represent a physiologically relevant source of this collagen epitope. Here, we define an endothelial cell mechano-signaling pathway in which a cryptic collagen epitope activates αvß3 leading to an Src and p38 MAPK-dependent cascade that leads to nuclear accumulation of Yes-associated protein (YAP) and stimulation of endothelial cell growth. Collectively, our findings not only provide evidence for a novel mechano-signaling pathway, but also define a possible therapeutic strategy to control αvß3 signaling by targeting a pro-angiogenic and inflammatory ligand of αvß3 rather than the receptor itself.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Colágeno/farmacologia , Células Endoteliais/metabolismo , Epitopos/farmacologia , Mecanotransdução Celular/efeitos dos fármacos , Neovascularização Fisiológica/efeitos dos fármacos , Fosfoproteínas/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Proteínas de Ciclo Celular , Linhagem Celular Tumoral , Colágeno/química , Células Endoteliais/citologia , Epitopos/química , Humanos , Integrina alfaVbeta3/genética , Integrina alfaVbeta3/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/genética , Mecanotransdução Celular/genética , Camundongos , Fosfoproteínas/genética , Fatores de Transcrição , Proteínas de Sinalização YAP , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Quinases da Família srcRESUMO
Evidence suggests that stromal cells play critical roles in tumor growth. Uncovering new mechanisms that control stromal cell behavior and their accumulation within tumors may lead to development of more effective treatments. We provide evidence that the HU177 cryptic collagen epitope is selectively generated within human ovarian carcinomas and this collagen epitope plays a role in SKOV-3 ovarian tumor growth in vivo. The ability of the HU177 epitope to regulate SKOV-3 tumor growth depends in part on its ability to modulate stromal cell behavior because targeting this epitope inhibited angiogenesis and, surprisingly, the accumulation of α-smooth muscle actin-expressing stromal cells. Integrin α10ß1 can serve as a receptor for the HU177 epitope in α-smooth muscle actin-expressing stromal cells and subsequently regulates Erk-dependent migration. These findings are consistent with a mechanism by which the generation of the HU177 collagen epitope provides a previously unrecognized α10ß1 ligand that selectively governs angiogenesis and the accumulation of stromal cells, which in turn secrete protumorigenic factors that contribute to ovarian tumor growth. Our findings provide a new mechanistic understanding into the roles by which the HU177 epitope regulates ovarian tumor growth and provide new insight into the clinical results from a phase 1 human clinical study of the monoclonal antibody D93/TRC093 in patients with advanced malignant tumors.
Assuntos
Proliferação de Células , Colágeno/metabolismo , Epitopos , Neoplasias Ovarianas/patologia , Microambiente Tumoral/fisiologia , Animais , Western Blotting , Adesão Celular/fisiologia , Proliferação de Células/fisiologia , Colágeno/química , Feminino , Xenoenxertos , Humanos , Camundongos , Neovascularização Patológica/metabolismo , Neoplasias Ovarianas/metabolismoRESUMO
A more complete understanding of the mechanisms that regulate the angiogenic switch, which contributes to the conversion of small dormant tumors to actively growing malignancies, is important for the development of more effective anti-angiogenic strategies for cancer therapy. While significant progress has been made in understanding the complex mechanisms by which integrin αvß3 expressed in endothelial cells governs angiogenesis, less is known concerning the ability of αvß3 expressed within the tumor cell compartment to modulate the angiogenic output of a tumor. Here we provide evidence that αvß3 expressed in melanoma cells may contribute to the suppression of IGFBP-4, an important negative regulator of IGF-1 signaling. Given the multiple context-dependent roles for αvß3 in angiogenesis and tumor progression, our novel findings provide additional molecular insight into how αvß3 may govern the angiogenic switch by a mechanism associated with a p38 MAPK and matrix metalloproteinases-dependent regulation of the endogenous angiogenesis inhibitor IGFBP-4.
Assuntos
Proteína 4 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Integrina alfaVbeta3/antagonistas & inibidores , Melanoma/fisiopatologia , Western Blotting , Linhagem Celular Tumoral , Proliferação de Células , Primers do DNA/genética , Imunofluorescência , Humanos , Imuno-Histoquímica , Melanoma/complicações , Neovascularização Patológica/etiologia , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Microtomografia por Raio-XRESUMO
An in-depth understanding of the molecular and cellular complexity of angiogenesis continues to advance as new stimulators and inhibitors of blood vessel formation are uncovered. Gaining a more complete understanding of the response of blood vessels to both stimulatory and inhibitory molecules will likely contribute to more effective strategies to control pathological angiogenesis. Here, we provide evidence that endothelial cell interactions with structurally altered collagen type IV may suppress the expression of insulin-like growth factor binding protein-4 (IGFBP-4), a well documented inhibitor of the IGF-1/IGF-1R signaling axis. We report for the first time that IGFBP-4 differentially inhibits angiogenesis induced by distinct growth factor signaling pathways as IGFBP-4 inhibited FGF-2- and IGF-1-stimulated angiogenesis but failed to inhibit VEGF-induced angiogenesis. The resistance of VEGF-stimulated angiogenesis to IGFBP-4 inhibition appears to depend on sustained activation of p38 MAPK as blocking its activity restored the anti-angiogenic effects of IGFBP-4 on VEGF-induced blood vessel growth in vivo. These novel findings provide new insight into how blood vessels respond to endogenous inhibitors during angiogenesis stimulated by distinct growth factor signaling pathways.
Assuntos
Inibidores da Angiogênese/metabolismo , Células Endoteliais/metabolismo , Proteína 4 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Neovascularização Fisiológica , Fator A de Crescimento do Endotélio Vascular/metabolismo , Inibidores da Angiogênese/genética , Animais , Embrião de Galinha , Células Endoteliais/citologia , Humanos , Proteína 4 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like I/metabolismo , Receptor IGF Tipo 1/genética , Receptor IGF Tipo 1/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
It is well accepted that complex biological processes such as angiogenesis are not controlled by a single family of molecules or individually isolated signaling pathways. In this regard, new insight into the interconnected mechanisms that regulate angiogenesis might be gained by examining this process from a more global network perspective. The coordination of signaling cues from both outside and inside many different cell types is required for the successful completion of angiogenesis. Evidence is accumulating that the multifunctional integrin family of cell adhesion receptors represent an important group of molecules that play active roles in sensing, integrating, and distributing a diverse set of signals that regulate many cellular events required for angiogenesis. Given the ability of integrins to bind numerous extracellular ligands and transmit signals in a bi-directional fashion, we will discuss the multiple ways by which integrins may serve as a functional hub during pathological angiogenesis. In addition, we will highlight potential imaging and therapeutic strategies based on the expanding new insight into integrin function.
Assuntos
Integrinas/fisiologia , Neoplasias/irrigação sanguínea , Neovascularização Patológica/metabolismo , Inibidores da Angiogênese/uso terapêutico , Humanos , Neovascularização Patológica/prevenção & controleRESUMO
Endoglin is an accessory receptor for TGF-ß that has been implicated in prostate cancer cell detachment, migration, and invasiveness. However, the pathophysiologic significance of endoglin with respect to prostate tumorigenesis has yet to be fully established. In this study, we addressed this question by investigation of endoglin-dependent prostate cancer progression in a TRAMP (transgenic adenocarcinoma mouse prostate) mouse model where endoglin was genetically deleted. In this model, endoglin was haploinsufficient such that its allelic deletion slightly increased the frequency of tumorigenesis, yet produced smaller, less vascularized, and less metastatic tumors than TRAMP control tumors. Most strikingly, TRAMP:eng(+/-)-derived tumors lacked the pronounced infiltration of carcinoma-associated fibroblasts (CAF) that characterize TRAMP prostate tumors. Studies in human primary prostate-derived stromal cells (PrSC) confirmed that suppressing endoglin expression decreased cell proliferation, the ability to recruit endothelial cells, and the ability to migrate in response to tumor cell-conditioned medium. We found increased levels of secreted insulin-like growth factor-binding proteins (IGFBP) in the conditioned medium from endoglin-deficient PrSCs and that endoglin-dependent regulation of IGFBP-4 secretion was crucial for stromal cell-conditioned media to stimulate prostate tumor cell growth. Together, our results firmly establish the pathophysiologic involvement of endoglin in prostate cancer progression; furthermore, they show how endoglin acts to support the viability of tumor-infiltrating CAFs in the tumor microenvironment to promote neovascularization and growth.