RESUMO
Malignant melanoma, an aggressive skin cancer with a poor prognosis, frequently features BRAFV600E mutation resulting in activation of the MAPK pathway and melanocyte proliferation and survival. BRAFV600E inhibitors like vemurafenib and dabrafenib have enhanced patient survival, yet drug resistance remains a significant challenge. We investigated the role of the ERK5 pathway in BRAFV600E melanoma cells and cells with acquired resistance to PLX4720 (vemurafenib) and dabrafenib. In BRAFV600E melanoma, ERK5 inhibition minimally affected viability compared to ERK1/2 inhibition. In vemurafenib-resistant cells, ERK5 inhibition alone didn't impact viability or restore drug sensitivity to vemurafenib. However, in dabrafenib-resistant cells, ERK5 inhibition reduced viability and enhanced the anti-proliferative effect of MEK1/2 inhibition. Targeting the ERK5 pathway may represent a therapeutic opportunity in dabrafenib-resistant melanoma.
Assuntos
Resistencia a Medicamentos Antineoplásicos , Imidazóis , Melanoma , Proteína Quinase 7 Ativada por Mitógeno , Oximas , Proteínas Proto-Oncogênicas B-raf , Vemurafenib , Oximas/farmacologia , Humanos , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas B-raf/metabolismo , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Melanoma/tratamento farmacológico , Melanoma/genética , Melanoma/patologia , Melanoma/metabolismo , Imidazóis/farmacologia , Vemurafenib/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Linhagem Celular Tumoral , Proteína Quinase 7 Ativada por Mitógeno/metabolismo , Proteína Quinase 7 Ativada por Mitógeno/genética , Indóis/farmacologia , Sulfonamidas/farmacologia , Proliferação de Células/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/metabolismo , Inibidores de Proteínas Quinases/farmacologia , MutaçãoRESUMO
Extracellular-signal-regulated kinase 5 (ERK5) is critical for normal cardiovascular development. Previous studies have defined a canonical pathway for ERK5 activation, showing that ligand stimulation leads to MEK5 activation resulting in dual phosphorylation of ERK5 on Thr218/Tyr220 residues within the activation loop. ERK5 then undergoes a conformational change, facilitating phosphorylation on residues in the C-terminal domain and translocation to the nucleus where it regulates MEF2 transcriptional activity. Our previous research into the importance of ERK5 in endothelial cells highlighted its role in VEGF-mediated tubular morphogenesis and cell survival, suggesting that ERK5 played a unique role in endothelial cells. Our current data show that in contrast to EGF-stimulated HeLa cells, VEGF-mediated ERK5 activation in human dermal microvascular endothelial cells (HDMECs) does not result in C-terminal phosphorylation of ERK5 and translocation to the nucleus, but instead to a more plasma membrane/cytoplasmic localisation. Furthermore, the use of small-molecule inhibitors to MEK5 and ERK5 shows that instead of regulating MEF2 activity, VEGF-mediated ERK5 is important for regulating AKT activity. Our data define a novel pathway for ERK5 activation in endothelial cells leading to cell survival.
Assuntos
Proteína Quinase 7 Ativada por Mitógeno , Proteínas Proto-Oncogênicas c-akt , Fator A de Crescimento do Endotélio Vascular , Humanos , Células Endoteliais/metabolismo , Células HeLa , Proteína Quinase 7 Ativada por Mitógeno/metabolismo , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Regenerative medicine therapies hold enormous potential for a variety of currently incurable conditions with high unmet clinical need. Most progress in this field to date has been achieved with cell-based regenerative medicine therapies, with over a thousand clinical trials performed up to 2015. However, lack of adequate safety and efficacy data is currently limiting wider uptake of these therapies. To facilitate clinical translation, non-invasive in vivo imaging technologies that enable careful evaluation and characterisation of the administered cells and their effects on host tissues are critically required to evaluate their safety and efficacy in relevant preclinical models. This article reviews the most common imaging technologies available and how they can be applied to regenerative medicine research. We cover details of how each technology works, which cell labels are most appropriate for different applications, and the value of multi-modal imaging approaches to gain a comprehensive understanding of the responses to cell therapy in vivo.