RESUMO
Melanoma is the deadliest skin cancer, with a poor prognosis in advanced stages. While available treatments have improved survival, long-term benefits are still unsatisfactory. The mitogen-activated protein kinase extracellular signal-regulated kinase 5 (ERK5) promotes melanoma growth, and ERK5 inhibition determines cellular senescence and the senescence-associated secretory phenotype. Here, latent-transforming growth factor ß-binding protein 1 (LTBP1) mRNA was found to be up-regulated in A375 and SK-Mel-5 BRAF V600E melanoma cells after ERK5 inhibition. In keeping with a key role of LTBP1 in regulating transforming growth factor ß (TGF-ß), TGF-ß1 protein levels were increased in lysates and conditioned media of ERK5-knockdown (KD) cells, and were reduced upon LTBP1 KD. Both LTBP1 and TGF-ß1 proteins were increased in melanoma xenografts in mice treated with the ERK5 inhibitor XMD8-92. Moreover, treatment with conditioned media from ERK5-KD melanoma cells reduced cell proliferation and invasiveness, and TGF-ß1-neutralizing antibodies impaired these effects. In silico data sets revealed that higher expression levels of both LTBP1 and TGF-ß1 mRNA were associated with better overall survival of melanoma patients. Increased LTBP1 or TGF-ß1 expression played a beneficial role in patients treated with anti-PD1 immunotherapy, making a possible immunosuppressive role of LTBP1/TGF-ß1 unlikely upon ERK5 inhibition. This study, therefore, identifies additional desirable effects of ERK5 targeting, providing evidence of an ERK5-dependent tumor-suppressive role of TGF-ß in melanoma.
Assuntos
Proliferação de Células , Proteínas de Ligação a TGF-beta Latente , Melanoma , Proteína Quinase 7 Ativada por Mitógeno , Fator de Crescimento Transformador beta1 , Melanoma/metabolismo , Melanoma/patologia , Melanoma/genética , Melanoma/tratamento farmacológico , Humanos , Proteínas de Ligação a TGF-beta Latente/metabolismo , Proteínas de Ligação a TGF-beta Latente/genética , Animais , Proteína Quinase 7 Ativada por Mitógeno/metabolismo , Proteína Quinase 7 Ativada por Mitógeno/genética , Camundongos , Fator de Crescimento Transformador beta1/metabolismo , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/genética , Linhagem Celular Tumoral , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Endometriosis is a chronic gynecological disease affecting ~10% women in the reproductive age characterized by the growth of endometrial glands and stroma outside the uterine cavity. The inflammatory process has a key role in the initiation and progression of the disorder. Currently, there are no available early diagnostic tests and therapy relies exclusively on symptomatic drugs, so that elucidation of the complex molecular mechanisms involved in the pathogenesis of endometriosis is an unmet need. The signaling of the bioactive sphingolipid sphingosine 1-phosphate (S1P) is deeply dysregulated in endometriosis. S1P modulates a variety of fundamental cellular processes, including inflammation, neo-angiogenesis, and immune responses acting mainly as ligand of a family of G-protein-coupled receptors named S1P receptors (S1PR), S1P1-5 . Here, we demonstrated that the mitogen-activated protein kinase ERK5, that is expressed in endometriotic lesions as determined by quantitative PCR, is activated by S1P in human endometrial stromal cells. S1P-induced ERK5 activation was shown to be triggered by S1P1/3 receptors via a SFK/MEK5-dependent axis. S1P-induced ERK5 activation was, in turn, responsible for the increase of reactive oxygen species and proinflammatory cytokine expression in human endometrial stromal cells. The present findings indicate that the S1P signaling, via ERK5 activation, supports a proinflammatory response in the endometrium and establish the rationale for the exploitation of innovative therapeutic targets for endometriosis.
Assuntos
Endometriose , Humanos , Feminino , Masculino , Espécies Reativas de Oxigênio , Esfingosina , EsfingolipídeosRESUMO
BACKGROUND AND AIMS: Cholangiocarcinoma (CCA) is characterized by high resistance to chemotherapy and poor prognosis. Several oncogenic pathways converge on activation of extracellular signal-regulated kinase 5 (ERK5), whose role in CCA has not been explored. The aim of this study was to investigate the role of ERK5 in the biology of CCA. APPROACH AND RESULTS: ERK5 expression was detected in two established (HuCCT-1 and CCLP-1) and two primary human intrahepatic CCA cell lines (iCCA58 and iCCA60). ERK5 phosphorylation was increased in CCA cells exposed to soluble mediators. In both HuCCT-1 and CCLP-1 cells, ERK5 was localized in the nucleus, and exposure to fetal bovine serum (FBS) further increased the amount of nuclear ERK5. In human CCA specimens, ERK5 mRNA expression was increased in tumor cells and positively correlated with portal invasion. ERK5 protein levels were significantly associated with tumor grade. Growth, migration, and invasion of CCA cells were decreased when ERK5 was silenced using specific short hairpin RNA (shRNA). The inhibitory effects on CCA cell proliferation, migration and invasion were recapitulated by treatment with small molecule inhibitors targeting ERK5. In addition, expression of the angiogenic factors VEGF and angiopoietin 1 was reduced after ERK5 silencing. Conditioned medium from ERK5-silenced cells had a lower ability to induce tube formation by human umbilical vein endothelial cells and to induce migration of myofibroblasts and monocytes/macrophages. In mice, subcutaneous injection of CCLP-1 cells silenced for ERK5 resulted in less frequent tumor development and smaller size of xenografts compared with cells transfected with nontargeting shRNA. CONCLUSIONS: ERK5 is a key mediator of growth and migration of CCA cells and supports a protumorigenic crosstalk between the tumor and the microenvironment.
Assuntos
Neoplasias dos Ductos Biliares/genética , Ductos Biliares Intra-Hepáticos , Colangiocarcinoma/genética , Proteína Quinase 7 Ativada por Mitógeno/genética , Animais , Neoplasias dos Ductos Biliares/metabolismo , Neoplasias dos Ductos Biliares/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Colangiocarcinoma/metabolismo , Colangiocarcinoma/patologia , Meios de Cultivo Condicionados , Técnicas de Silenciamento de Genes , Células Endoteliais da Veia Umbilical Humana , Humanos , Macrófagos , Camundongos , Monócitos , Miofibroblastos , Gradação de Tumores , Invasividade Neoplásica , Transplante de Neoplasias , Neovascularização Patológica/genética , Fenótipo , RNA Mensageiro/metabolismoRESUMO
Mitogen-activated protein kinase (MAPK) pathways are prominently involved in the onset and progression of cancer [...].
Assuntos
Proteínas Quinases Ativadas por Mitógeno , Neoplasias , Humanos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/genéticaRESUMO
Malignant melanoma is the deadliest skin cancer, with a poor prognosis in advanced stages. We recently showed that the extracellular signal-regulated kinase 5 (ERK5), encoded by the MAPK7 gene, plays a pivotal role in melanoma by regulating cell functions necessary for tumour development, such as proliferation. Hedgehog-GLI signalling is constitutively active in melanoma and is required for proliferation. However, no data are available in literature about a possible interplay between Hedgehog-GLI and ERK5 pathways. Here, we show that hyperactivation of the Hedgehog-GLI pathway by genetic inhibition of the negative regulator Patched 1 increases the amount of ERK5 mRNA and protein. Chromatin immunoprecipitation showed that GLI1, the major downstream effector of Hedgehog-GLI signalling, binds to a functional non-canonical GLI consensus sequence at the MAPK7 promoter. Furthermore, we found that ERK5 is required for Hedgehog-GLI-dependent melanoma cell proliferation, and that the combination of GLI and ERK5 inhibitors is more effective than single treatments in reducing cell viability and colony formation ability in melanoma cells. Together, these findings led to the identification of a novel Hedgehog-GLI-ERK5 axis that regulates melanoma cell growth, and shed light on new functions of ERK5, paving the way for new therapeutic options in melanoma and other neoplasms with active Hedgehog-GLI and ERK5 pathways.
Assuntos
MAP Quinase Quinase 5/genética , Melanoma/genética , Proteína Quinase 7 Ativada por Mitógeno/genética , Neoplasias Cutâneas/genética , Proteína GLI1 em Dedos de Zinco/metabolismo , Animais , Linhagem Celular , Proliferação de Células , Sobrevivência Celular , Imunoprecipitação da Cromatina , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Proteínas Hedgehog/metabolismo , Humanos , MAP Quinase Quinase 5/metabolismo , Melanoma/metabolismo , Camundongos , Proteína Quinase 7 Ativada por Mitógeno/metabolismo , Células NIH 3T3 , Receptor Patched-1/metabolismo , Transdução de Sinais , Neoplasias Cutâneas/metabolismo , Melanoma Maligno CutâneoRESUMO
Fibroblast growth factor receptor 2 (FGFR2) might have an important role in the pathogenesis and biology of cholangiocarcinoma (CCA). We examined FGFR expression in CCA tumor specimens obtained from patients and CCA cell lines, and then determined the effects of the novel FGFR inhibitor, derazantinib (DZB; formally, ARQ 087), which is currently in clinical phase 2 trials for intrahepatic CCA. DZB inhibited the growth of CCA cell lines in a dose-dependent manner, and extracellular signal-regulated kinase 1/2 and AKT. It also activated apoptotic and cell growth arrest signaling. DZB reduced the in vitro invasiveness and the expression of key epithelial-mesenchymal transition genes. The in vitro data correlated with the expression of FGFRs in human CCA specimens by immunohistochemistry (FGFR1, 30% positive; and FGFR2, 65% positive) and the CCA cell lines assayed by Western blot analysis. These correlated in vitro studies suggest that FGFR may play an important role in the pathogenesis and biology of CCA. Our findings support the notion that FGFR inhibitors, like DZB, should be further evaluated at the clinical stage as targeted therapy for CCA treatment.
Assuntos
Compostos de Anilina/farmacologia , Neoplasias dos Ductos Biliares/patologia , Colangiocarcinoma/patologia , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Quinazolinas/farmacologia , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/antagonistas & inibidores , Neoplasias dos Ductos Biliares/tratamento farmacológico , Neoplasias dos Ductos Biliares/metabolismo , Proliferação de Células , Colangiocarcinoma/tratamento farmacológico , Colangiocarcinoma/metabolismo , Humanos , Fosforilação , Transdução de Sinais , Células Tumorais CultivadasRESUMO
The importance of mitogen-activated protein kinases (MAPK) in human pathology is underlined by the relevance of abnormalities of MAPK-related signaling pathways to a number of different diseases, including inflammatory disorders and cancer. One of the key events in MAPK signaling, especially with respect to pro-proliferative effects that are crucial for the onset and progression of cancer, is MAPK nuclear translocation and its role in the regulation of gene expression. The extracellular signal-regulated kinase 5 (ERK5) is the most recently discovered classical MAPK and it is emerging as a possible target for cancer treatment. The bigger size of ERK5 when compared to other MAPK enables multiple levels of regulation of its expression and activity. In particular, the phosphorylation of kinase domain and C-terminus, as well as post-translational modifications and chaperone binding, are involved in ERK5 regulation. Likewise, different mechanisms control ERK5 nucleo-cytoplasmic shuttling, underscoring the key role of ERK5 in the nuclear compartment. In this review, we will focus on the mechanisms involved in ERK5 trafficking between cytoplasm and nucleus, and discuss how these processes might be exploited to design new strategies for cancer treatment.
Assuntos
Núcleo Celular/metabolismo , Citoplasma/metabolismo , Proteína Quinase 7 Ativada por Mitógeno/metabolismo , Neoplasias/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Terapia de Alvo Molecular , Neoplasias/tratamento farmacológico , Transporte ProteicoRESUMO
Chronic myeloid leukemia (CML) is a hematopoietic stem cell (HSC)-driven neoplasia characterized by expression of the constitutively active tyrosine kinase BCR/Abl. CML therapy based on tyrosine kinase inhibitors (TKIs) is highly effective in inducing remission but not in targeting leukemia stem cells (LSCs), which sustain minimal residual disease and are responsible for CML relapse following discontinuation of treatment. The identification of molecules capable of targeting LSCs appears therefore of primary importance to aim at CML eradication. LSCs home in bone marrow areas at low oxygen tension, where HSCs are physiologically hosted. This study addresses the effects of pharmacological inhibition of hypoxia-inducible factor-1 (HIF-1), a critical regulator of LSC survival, on the maintenance of CML stem cell potential. We found that the HIF-1 inhibitor acriflavine (ACF) decreased survival and growth of CML cells. These effects were paralleled by decreased expression of c-Myc and stemness-related genes. Using different in vitro stem cell assays, we showed that ACF, but not TKIs, targets the stem cell potential of CML cells, including primary cells explanted from 12 CML patients. Moreover, in a murine CML model, ACF decreased leukemia development and reduced LSC maintenance. Importantly, ACF exhibited significantly less-severe effects on non-CML hematopoietic cells in vitro and in vivo. Thus, we propose ACF, a US Food and Drug Administration (FDA)-approved drug for nononcological use in humans, as a novel therapeutic approach to prevent CML relapse and, in combination with TKIs, enhance induction of remission.
Assuntos
Acriflavina/farmacologia , Sistemas de Liberação de Medicamentos/métodos , Fator 1 Induzível por Hipóxia/antagonistas & inibidores , Leucemia Mielogênica Crônica BCR-ABL Positiva , Proteínas de Neoplasias/antagonistas & inibidores , Neoplasias Experimentais , Células-Tronco Neoplásicas/metabolismo , Animais , Sobrevivência Celular , Humanos , Fator 1 Induzível por Hipóxia/metabolismo , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Camundongos , Células NIH 3T3 , Proteínas de Neoplasias/metabolismo , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/patologia , Células-Tronco Neoplásicas/patologiaRESUMO
Extracellular signal-regulated kinase 5 (ERK5) belongs to the mitogen-activated protein kinase (MAPK) family that consists of highly conserved enzymes expressed in all eukaryotic cells and elicits several biological responses, including cell survival, proliferation, migration, and differentiation. In recent years, accumulating lines of evidence point to a relevant role of ERK5 in the onset and progression of several types of cancer. In particular, it has been reported that ERK5 is a key signaling molecule involved in almost all the biological features of cancer cells so that its targeting is emerging as a promising strategy to suppress tumor growth and spreading. Based on that, in this review, we pinpoint the hallmark-specific role of ERK5 in cancer in order to identify biological features that will potentially benefit from ERK5 targeting.
Assuntos
Proteína Quinase 7 Ativada por Mitógeno/metabolismo , Neoplasias/etiologia , Neoplasias/metabolismo , Animais , Biomarcadores , Proliferação de Células , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Suscetibilidade a Doenças , Metabolismo Energético , Instabilidade Genômica , Humanos , Imunidade , Sistema de Sinalização das MAP Quinases , Proteína Quinase 7 Ativada por Mitógeno/genética , Invasividade Neoplásica , Metástase Neoplásica , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Transdução de SinaisRESUMO
The Hedgehog-GLI (HH-GLI) signaling is of critical importance during embryonic development, where it regulates a number of cellular processes, including patterning, proliferation and differentiation. Its aberrant activation has been linked to several types of cancer. HH-GLI signaling is triggered by binding of ligands to the transmembrane receptor patched and is subsequently mediated by transcriptional effectors belonging to the GLI family, whose function is fine tuned by a series of molecular interactions and modifications. Several HH-GLI inhibitors have been developed and are in clinical trials. Similarly, the mitogen-activated protein kinases (MAPK) are involved in a number of biological processes and play an important role in many diseases including cancer. Inhibiting molecules targeting MAPK signaling, especially those elicited by the MEK1/2-ERK1/2 pathway, have been developed and are moving into clinical trials. ERK1/2 may be activated as a consequence of aberrant activation of upstream signaling molecules or during development of drug resistance following treatment with kinase inhibitors such as those for PI3K or BRAF. Evidence of a crosstalk between HH-GLI and other oncogenic signaling pathways has been reported in many tumor types, as shown by recent reviews. Here we will focus on the interaction between HH-GLI and the final MAPK effectors ERK1/2, p38 and JNK in cancer in view of its possible implications for cancer therapy. Several reports highlight the existence of a consistent crosstalk between HH signaling and MAPK, especially with the MEK1/2-ERK1/2 pathway, and this fact should be taken into consideration for designing optimal treatment and prevent tumor relapse.
Assuntos
Proteínas Hedgehog/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Neoplasias/metabolismo , Proteínas Oncogênicas/metabolismo , Transdução de Sinais , Transativadores/metabolismo , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Proteínas Hedgehog/antagonistas & inibidores , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Sistema de Sinalização das MAP Quinases , Proteína Quinase 7 Ativada por Mitógeno/metabolismo , Neoplasias/diagnóstico , Neoplasias/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Transdução de Sinais/efeitos dos fármacos , Proteína GLI1 em Dedos de Zinco , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Prostaglandin E2 (PGE2), a key mediator of immunity, inflammation, and cancer, acts through 4 G-protein-coupled E-prostanoid receptors (EPs 1-4). Crosstalk between EPs and receptor tyrosine kinases also occurs. Colony-stimulating factor-1 receptor (CSF-1R) is an RTK that sustains the survival, proliferation, and motility of monocytes/macrophages, which are an essential component of innate immunity and cancer development. The aim of this study was to investigate on a possible crosstalk between EP and CSF-1R. In BAC1.2F5 and RAW264.7 murine macrophages, CSF-1 (EC50 = 18.1 and 10.2 ng/ml, respectively) and PGE2 (EC50 = 1.5 and 5.5 nM, respectively) promoted migration. PGE2 induced rapid CSF-1R phosphorylation that was dependent on Src family kinases (SFKs). CSF-1R inhibition reduced PGE2-elicited ERK1/2 phosphorylation and macrophage migration, indicating that CSF-1R plays a role in PGE2-mediated immunoregulation. EP4 appeared responsible for functional PGE2/CSF-1R crosstalk. Furthermore, PGE2 synergized with CSF-1 in inducing ERK1/2 phosphorylation and macrophage migration. ERK1/2 inhibition completely blocked migration induced by the combination CSF-1/PGE2. CSF-1/PGE2 functional interaction with respect to migration also occurred in bone marrow-derived murine macrophages (EC50 CSF-1, 6.7 ng/ml; EC50 PGE2, 16.7 nM). These results indicated that PGE2 transactivates CSF-1R and synergizes with its signaling at ERK1/2 level in promoting macrophage migration.
Assuntos
Movimento Celular/efeitos dos fármacos , Dinoprostona/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Fator Estimulador de Colônias de Macrófagos/farmacologia , Macrófagos/efeitos dos fármacos , Receptor de Fator Estimulador de Colônias de Macrófagos/metabolismo , Animais , Linhagem Celular , Células Cultivadas , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Immunoblotting , Macrófagos/citologia , Macrófagos/metabolismo , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Células NIH 3T3 , Fosforilação/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacosRESUMO
Research on the nanoscale membrane structures known as lipid rafts is relevant to the fields of cancer biology, inflammation and ischaemia. Lipid rafts recruit molecules critical to signalling and regulation of the invasion process in malignant cells, the leukocytes that provide immunity in inflammation and the endothelial cells that build blood and lymphatic vessels, as well as the patterning of neural networks. As angiogenesis is a common denominator, regulation of receptors and signalling molecules critical to angiogenesis is central to the design of new approaches aimed at reducing, promoting or normalizing the angiogenic process. The goal of this review is to highlight some of the key issues that indicate the involvement of endothelial cell lipid rafts at each step of so-called 'sprouting angiogenesis', from stimulation of the vascular endothelial growth factor to the choice of tip cells, activation of migratory and invasion pathways, recruitment of molecules that guide axons in vascular patterning and maturation of blood vessels. Finally, the review addresses opportunities for future studies to define how these lipid domains (and their constituents) may be manipulated to stimulate the so-called 'normalization' of vascular networks within tumors, and be identified as the main target, enabling the development of more efficient chemotherapeutics and cancer immunotherapies.
Assuntos
Vasos Sanguíneos/metabolismo , Microdomínios da Membrana/metabolismo , Axônios/metabolismo , Caveolinas/metabolismo , Células Endoteliais/metabolismo , Humanos , Neoplasias/metabolismo , Neoplasias/patologia , Neovascularização Patológica , Transdução de Sinais , Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
OBJECTIVE: The extracellular signal-regulated kinase 5 (ERK5 or BMK1) is involved in tumour development. The ERK5 gene may be amplified in hepatocellular carcinoma (HCC), but its biological role has not been clarified. In this study, we explored the role of ERK5 expression and activity in HCC in vitro and in vivo. DESIGN: ERK5 expression was evaluated in human liver tissue. Cultured HepG2 and Huh-7 were studied after ERK5 knockdown by siRNA or in the presence of the specific pharmacological inhibitor, XMD8-92. The role of ERK5 in vivo was assessed using mouse Huh-7 xenografts. RESULTS: In tissue specimens from patients with HCC, a higher percentage of cells with nuclear ERK5 expression was found both in HCC and in the surrounding cirrhotic tissue compared with normal liver tissue. Inhibition of ERK5 decreased HCC cell proliferation and increased the proportion of cells in G0/G1 phase. These effects were associated with increased expression of p27 and p15 and decreased CCND1. Treatment with XMD8-92 or ERK5 silencing prevented cell migration induced by epidermal growth factor or hypoxia and caused cytoskeletal remodelling. In mouse xenografts, the rate of tumour appearance and the size of tumours were significantly lower when Huh-7 was silenced for ERK5. Moreover, systemic treatment with XMD8-92 of mice with established HCC xenografts markedly reduced tumour growth and decreased the expression of the proto-oncogene c-Rel. CONCLUSIONS: ERK5 regulates the biology of HCC cells and modulates tumour development and growth in vivo. This pathway should be investigated as a possible therapeutic target in HCC.
Assuntos
Carcinoma Hepatocelular/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/genética , Proteína Quinase 7 Ativada por Mitógeno/genética , Animais , Biópsia por Agulha , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/fisiopatologia , Proliferação de Células/genética , Modelos Animais de Doenças , Progressão da Doença , Xenoenxertos , Humanos , Imuno-Histoquímica , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/fisiopatologia , Camundongos , Transplante de Neoplasias , Proto-Oncogene Mas , RNA Interferente Pequeno/análise , Sensibilidade e Especificidade , Células Tumorais CultivadasRESUMO
Receptor tyrosine kinases (RTK) have long being studied with respect to the "canonical" signaling. This includes ligand-induced activation of a receptor tyrosine kinase at the cell surface that leads to receptor dimerization, followed by its phosphorylation in the intracellular domain and activation. The activated receptor then recruits cytoplasmic signaling molecules including other kinases. Activation of the downstream signaling cascade frequently leads to changes in gene expression following nuclear translocation of downstream targets. However, RTK themselves may localize within the nucleus, as either full-length molecules or cleaved fragments, with or without their ligands. Significant differences in this mechanism have been reported depending on the individual RTK, cellular context or disease. Accumulating evidences indicate that the colony-stimulating factor-1 receptor (CSF-1R) may localize within the nucleus. To date, however, little is known about the mechanism of CSF-1R nuclear shuttling, as well as the functional role of nuclear CSF-1R.
Assuntos
Núcleo Celular/metabolismo , Receptor de Fator Estimulador de Colônias de Macrófagos/metabolismo , Transporte Ativo do Núcleo Celular , Animais , Humanos , Ligantes , Fator Estimulador de Colônias de Macrófagos/genética , Fator Estimulador de Colônias de Macrófagos/metabolismo , Camundongos , Regiões Promotoras Genéticas , Ligação Proteica , Estrutura Terciária de Proteína , Receptor de Fator Estimulador de Colônias de Macrófagos/química , Transdução de SinaisRESUMO
The mitogen-activated protein kinase (MAPK) extracellular signal-regulated kinase 5 (ERK5) is emerging as a promising target in cancer. Indeed, alterations of the MEK5/ERK5 pathway are present in many types of cancer, including melanoma. One of the key events in MAPK signalling is MAPK nuclear translocation and its subsequent regulation of gene expression. Likewise, the effects of ERK5 in supporting cancer cell proliferation have been linked to its nuclear localization. Despite many processes regulating ERK5 nuclear translocation having been determined, the nuclear transporters involved have not yet been identified. Here, we investigated the role of importin subunit alpha (α importin) and importin subunit beta-1 (importin ß1) in ERK5 nuclear shuttling to identify additional targets for cancer treatment. Either importin ß1 knockdown or the α/ß1 importin inhibitor ivermectin reduced the nuclear amount of overexpressed and endogenous ERK5 in HEK293T and A375 melanoma cells, respectively. These results were confirmed in single-molecule microscopy in HeLa cells. Moreover, immunofluorescence analysis showed that ivermectin impairs epidermal growth factor (EGF)-induced ERK5 nuclear shuttling in HeLa cells. Both co-immunoprecipitation experiments and proximity ligation assay provided evidence that ERK5 and importin ß1 interact and that this interaction is further induced by EGF administration and prevented by ivermectin treatment. The combination of ivermectin and the ERK5 inhibitor AX15836 synergistically reduced cell viability and colony formation ability in A375 and HeLa cells and was more effective than single treatments in preventing the growth of A375 and HeLa spheroids. The increased reduction of cell viability upon the same combination was also observed in patient-derived metastatic melanoma cells. The combination of ivermectin and ERK5 inhibitors other than AX15836 provided similar effects on cell viability. The identification of importin ß1 as the nuclear transporter of ERK5 may be exploited for additional ERK5-inhibiting strategies for cancer therapy.
RESUMO
Lung cancer is the leading cause of cancer-related deaths worldwide, with non-small cell lung cancer (NSCLC) constituting approximately 84 % of all lung cancer cases. The role of inflammation in the initiation and progression of NSCLC tumors has been the focus of extensive research. Among the various inflammatory mediators, prostaglandin E2 (PGE2) plays a pivotal role in promoting the aggressiveness of epithelial tumors through multiple mechanisms, including the stimulation of growth, evasion of apoptosis, invasion, and induction of angiogenesis. The Extracellular signal-Regulated Kinase 5 (ERK5), the last discovered member among conventional mitogen-activated protein kinases (MAPK), is implicated in cancer-associated inflammation. In this study, we explored whether ERK5 is involved in the process of tumorigenesis induced by PGE2. Using A549 and PC9 NSCLC cell lines, we found that PGE2 triggers the activation of ERK5 via the EP1 receptor. Moreover, both genetic and pharmacological inhibition of ERK5 reduced PGE2-induced proliferation, migration, invasion and stemness of A549 and PC9 cells, indicating that ERK5 plays a critical role in PGE2-induced tumorigenesis. In summary, our study underscores the pivotal role of the PGE2/EP1/ERK5 axis in driving the malignancy of NSCLC cells in vitro. Targeting this axis holds promise as a potential avenue for developing novel therapeutic strategies aimed at controlling the advancement of NSCLC.
RESUMO
Oxidative stress regulates many physiological and pathological processes. Indeed, a low increase in the basal level of reactive oxygen species (ROS) is essential for various cellular functions, including signal transduction, gene expression, cell survival or death, as well as antioxidant capacity. However, if the amount of generated ROS overcomes the antioxidant capacity, excessive ROS results in cellular dysfunctions as a consequence of damage to cellular components, including DNA, lipids and proteins, and may eventually lead to cell death or carcinogenesis. Both in vitro and in vivo investigations have shown that activation of the mitogen-activated protein kinase kinase 5/extracellular signal-regulated kinase 5 (MEK5/ERK5) pathway is frequently involved in oxidative stress-elicited effects. In particular, accumulating evidence identified a prominent role of this pathway in the anti-oxidative response. In this respect, activation of krüppel-like factor 2/4 and nuclear factor erythroid 2-related factor 2 emerged among the most frequent events in ERK5-mediated response to oxidative stress. This review summarizes what is known about the role of the MEK5/ERK5 pathway in the response to oxidative stress in pathophysiological contexts within the cardiovascular, respiratory, lymphohematopoietic, urinary and central nervous systems. The possible beneficial or detrimental effects exerted by the MEK5/ERK5 pathway in the above systems are also discussed.
Assuntos
Antioxidantes , Proteína Quinase 7 Ativada por Mitógeno , Antioxidantes/metabolismo , MAP Quinase Quinase 5/genética , MAP Quinase Quinase 5/metabolismo , Proteína Quinase 7 Ativada por Mitógeno/genética , Proteína Quinase 7 Ativada por Mitógeno/metabolismo , Estresse Oxidativo , Espécies Reativas de Oxigênio , Humanos , AnimaisRESUMO
Mitochondria are the major source of reactive oxygen species (ROS), whose aberrant production by dysfunctional mitochondria leads to oxidative stress, thus contributing to aging as well as neurodegenerative disorders and cancer. Cells efficiently eliminate damaged mitochondria through a selective type of autophagy, named mitophagy. Here, we demonstrate the involvement of the atypical MAP kinase family member MAPK15 in cellular senescence, by preserving mitochondrial quality, thanks to its ability to control mitophagy and, therefore, prevent oxidative stress. We indeed demonstrate that reduced MAPK15 expression strongly decreases mitochondrial respiration and ATP production, while increasing mitochondrial ROS levels. We show that MAPK15 controls the mitophagic process by stimulating ULK1-dependent PRKN Ser108 phosphorylation and inducing the recruitment of damaged mitochondria to autophagosomal and lysosomal compartments, thus leading to a reduction of their mass, but also by participating in the reorganization of the mitochondrial network that usually anticipates their disposal. Consequently, MAPK15-dependent mitophagy protects cells from accumulating nuclear DNA damage due to mitochondrial ROS and, consequently, from senescence deriving from this chronic DNA insult. Indeed, we ultimately demonstrate that MAPK15 protects primary human airway epithelial cells from senescence, establishing a new specific role for MAPK15 in controlling mitochondrial fitness by efficient disposal of old and damaged organelles and suggesting this kinase as a new potential therapeutic target in diverse age-associated human diseases.
Assuntos
Senescência Celular , MAP Quinases Reguladas por Sinal Extracelular , Mitofagia , Autofagia/genética , Senescência Celular/genética , Senescência Celular/fisiologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Mitofagia/genética , Mitofagia/fisiologia , Estresse Oxidativo/genética , Estresse Oxidativo/fisiologia , Espécies Reativas de Oxigênio/metabolismoRESUMO
This study was directed to deepen the effects of nutrient shortage on BCR/Ablprotein expression and signaling in chronic myeloid leukemia (CML) cells. The backbone of the study was cell culture in medium lacking glucose, the consumption of which we had previously shown to drive BCR/Ablprotein suppression, and glutamine, the other main nutrient besides glucose. In this context, we focused on the role of lactate, the main by-product of glucose metabolism under conditions of rapid cell growth, in particular as a modulator of the maintenance of CML stem/progenitor cell potential, a crucial determinant of disease course and relapse of disease. The results obtained indicated that lactate is a powerful surrogate of glucose to prevent the suppression of BCR/Abl signaling and is therefore capable to maintain BCR/Abl-dependent CML stem/progenitor cell potential. A number of metabolism-related functional and phenotypical features of CML cells were also determined. Among these, we focused on the effect of lactate on oxygen consumption rate, the dependence of this effect on the cell surface lactate carrier MCT-1, and the relationship of the lactate effect to pyruvate and to the activity of mitochondrial pyruvate carrier.