RESUMO
Although naloxone has been documented to exert neuroprotection in animal model of cerebral ischemia, the mechanism is not well understood. In this present study we investigated whether naloxone affected the mitochondrial apoptotic pathway in ischemic brain injury of rats. SD rats were subjected to a permanent middle cerebral artery occlusion surgery, and received naloxone (0.5, 1, 2 mg/kg, i.v.) immediately after ischemia. Neurological deficits were evaluated 24 h after ischemia using the McGraw Stroke Index, and then the rats were killed, and the brains were collected for further analyses. We show that naloxone treatment dose-dependently decreased the infarction volume and morphological injury, improved motor behavioral function, and markedly curtailed brain edema. Furthermore, naloxone administration significantly inhibited the nuclear translocation of NF-κB p65 and decreased the levels of nuclear NF-κB p65 in the ischemic penumbra. Naloxone administration also dose-dependently increased the NF-κB inhibitory protein (IκBα) levels and attenuated phosphorylated NIK and IKKα levels in the ischemic penumbra. In addition, naloxone administration dose-dependently increased Bcl-2 levels, decreased Bax levels, stabilized the mitochondrial transmembrane potential, and inhibited cytochrome c release and caspase 3 and caspase 9 activation. These results indicate that the neuroprotective effects of naloxone against ischemic brain injury involve the inhibition of NF-κB activation via the suppression of the NIK/IKKα/IκBα pathway and the obstruction of the mitochondrial apoptotic pathway in neurons.
Assuntos
Infarto da Artéria Cerebral Média/tratamento farmacológico , Naloxona/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Transdução de Sinais/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Quinase I-kappa B/metabolismo , Masculino , Mitocôndrias/efeitos dos fármacos , NF-kappa B/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Ratos Sprague-Dawley , Quinase Induzida por NF-kappaBRESUMO
We have previously reported that ginkgolides containing ginkgolides A and B (GKAB) reduce infarct size in a rat model of focal ischemia. c-Jun N-terminal kinase (JNK), also known as stress-activated kinase (SAPK), is a critical stress-responsive kinase activated by various brain insults. Previous studies have demonstrated a brief increase in p-SAPK/JNK levels after focal ischemic brain injuries. In this study, we sought to investigate whether the neuroprotective effects of GKAB in rat models of permanent focal cerebral ischemia are associated with the JNK signaling pathway. Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion by intraluminal suture blockade. GKAB was injected intravenously immediately after ischemia onset. Here we demonstrate in rats that GKAB reduces neuronal apoptosis and blocks the increase of p-SAPK/JNK levels and nuclear translocation after cerebral ischemia in a dose-dependent manner. Furthermore, we report that cerebral ischemia increases ischemia-induced induction of reactive oxygen species, and this effect was blocked by GKAB. In addition, we show that BimL is induced and attenuated by GKAB. GKAB also repressed the ischemia-induced increase in the expression of Bax and reversed the decline in expression of Bcl-2. Likewise, there was a reduction in the release or activation of several mitochondrial proapoptotic molecules, including cytochrome c, caspases 3 and 9, and PARP. Taken together, our findings strongly suggest that GKAB-mediated neuroprotective effects against focal ischemia act through the inhibition of p-SAPK/JNK activation, in which the obstruction of the mitochondrial apoptotic pathway via the JNK signaling pathway is a key downstream mechanism of GKAB.
Assuntos
Apoptose/efeitos dos fármacos , Isquemia Encefálica/metabolismo , Ginkgolídeos/farmacologia , Proteínas Quinases JNK Ativadas por Mitógeno/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Animais , Western Blotting , Isquemia Encefálica/patologia , Modelos Animais de Doenças , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Lactonas/farmacologia , Masculino , Mitocôndrias , Ratos , Ratos Sprague-Dawley , Espécies Reativas de OxigênioRESUMO
BACKGROUND: Ginkgolide B (GKB) is a major active component of the extracts of Ginkgo biloba leaves, and it has been used as an anti-cancer agent. However, it is unknown whether GKB has the therapeutic effects on lung cancer. Here, we studied the effects of GKB on lung cancer cells. METHODS: The effects of GKB on lung cancer cell proliferation and invasion were analyzed by cell counting kit (CCK-8) and cell invasion assays, respectively. Apoptosis was detected by flow cytometry. Western blot analysis was used to confirm the expression of autophagy-associated proteins in GKB-treated cells. Immunofluorescence analysis was used to analyze the level of light chain 3B (LC3B). RESULTS: Treatment with GKB time-dependently inhibited the proliferation and decreased the invasive capacity of A549 and H1975 cells. GKB induced apoptosis of these cells, but there was no significant effect on apoptosis compared to the control treatment. GKB-induced inhibition of cell proliferation and GKB-induced cell death were due to autophagy rather than apoptosis. GKB-induced autophagy of lung cancer cells was dependent on beclin-1, and autophagy-induced inhibition of the NLRP3 inflammasome contributed to the anti-tumor effect of GKB. CONCLUSIONS: GKB-mediated autophagy of lung cancer cells is beclin-1-dependent and results in inhibition of the NLRP3 inflammasome. Therefore, GKB might be a potential therapeutic candidate for the treatment of lung cancer.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Autofagia/efeitos dos fármacos , Proteína Beclina-1/metabolismo , Ginkgolídeos/farmacologia , Lactonas/farmacologia , Neoplasias Pulmonares/patologia , Células A549 , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Estrutura Molecular , Folhas de Planta/químicaRESUMO
Tumor-associated macrophages have been shown to promote tumor growth. They may have an obligatory function in angiogenesis, invasion, and metastasis through release of inflammatory mediators. Their presence in ovarian cancer has been correlated with poor prognosis in these patients. The human cationic antimicrobial protein-18 (hCAP18)/LL-37 was originally identified as an effector molecule of the innate immune system. It is released by innate immune cells, such as macrophages, to combat microorganisms. Previous studies have characterized the hCAP18/LL-37 as a growth factor that has been shown to promote ovarian tumor progression. However, the role hCAP18/LL-37 has in macrophage-promoted ovarian tumor development and how its expression is controlled in this context remains poorly understood. Here, we demonstrate in co-culture experiments of macrophages and ovarian cancer cells a significant increase in the in vitro proliferation and invasiveness of the tumor cells is observed. These enhanced growth and invasion properties correlated with hCAP18/LL-37 induction. HCAP18/LL-37 expression was diminished by addition of two neutralizing antibodies, TLR2 or TLR6, as well as Cyp27B1 or VDR inhibitors. Furthermore, either the TLR2 or TLR6 antibody reduced vitamin D3 signaling and tumor cell progression in vitro. Addition of Cyp27B1 or VDR inhibitors abrogated TLR2/6 activation-induced expression of hCAP18/LL-37 in macrophages. Knockdown of tumor-produced versican V1 by RNAi in these tumor cells led to a decreased induction of hCAP18/LL-37 in macrophages. Versican V1 knockdown also inhibited TLR2 and vitamin D3 signaling, as well as growth and invasiveness of these tumor cells in the in vitro co-culture. In summary, we have found that versican V1 enhances hCAP18/LL-37 expression in macrophages through activation of TLR2 and subsequent vitamin D-dependent mechanisms which promote ovarian tumor progression in vitro.
Assuntos
Catelicidinas/metabolismo , Colecalciferol/metabolismo , Regulação Neoplásica da Expressão Gênica , Macrófagos/metabolismo , Neoplasias Ovarianas/patologia , Receptor 2 Toll-Like/metabolismo , Versicanas/metabolismo , 25-Hidroxivitamina D3 1-alfa-Hidroxilase/genética , Peptídeos Catiônicos Antimicrobianos , Linhagem Celular Tumoral , Proliferação de Células , Progressão da Doença , Feminino , Humanos , Invasividade Neoplásica , Receptores de Calcitriol/genética , Transdução de Sinais , Esteroide Hidroxilases/genética , Receptor 6 Toll-Like/metabolismo , Microambiente Tumoral , Regulação para Cima , Vitamina D3 24-HidroxilaseRESUMO
CDA-2 (cell differentiation agent 2), a urinary preparation, has potent anti- proliferative and pro-apoptotic properties in cancer cells. However, the mechanisms of tumor inhibitory action of CDA-2 are far from clear, and especially there was no report on lung cancer. Here we demonstrate that CDA-2 and its main component phenylacetylglutamine (PG) reduce the metastatic lung tumor growth, and increases survival time after inoculation with Lewis lung carcinoma (LLC) cells in a dose-dependent manner in C57BL6 mice. Proliferative program analysis in cancer cells revealed a fundamental impact of CDA-2 and PG on proliferation and apoptosis, including Bcl-2, Bcl-XL, cIAP1, Survivin, PCNA, Ki-67 proteins and TUNEL assays. CDA-2 and PG significantly reduced NF-κB DNA-binding activity in lung cancer cells and in alveolar macrophages of tumor bearing mice and especially decreased the release of inflammatory factors including TNFα, IL-6, and KC. Furthermore, CDA-2 and PG decrease the expressions of TLR2, TLR6, and CD14, but not TLR1, TLR3, TLR4, and TLR9 in bone-marrow-derived macrophages (BMDM) of mice stimulated by LLC-conditioned medium (LLC-CM). Over-expressing TLR2 in BMDM prevented CDA-2 and PG from inhibiting NF-κB activation, as well as induction of TNFα and IL-6. TLR2:TLR6 complexes mediate the effect of NF-κB inactivation by CDA-2. In conclusion, CDA-2 potently inhibits lung tumor development by reduction of the inflammation in lung through suppression of NF-κB activation in myeloid cells, associating with modulation of TLR2 signaling.