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Impact of PAR-1 upregulation upon EXT-1kd on balancing resistance and platelet activation
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Várias doenças humanas são afetadas por proteínas da família das Exostosinas (EXT). Um
membro desta família, a Exostosina-1 (EXT-1), é conhecida por ser essencial na produção de
cadeias de sulfato de heparano, que se ligam a fatores de crescimento, influenciando a eficácia
de sinalização e atividade destas proteínas. Estudos ainda não publicados do nosso grupo
demonstraram que o silenciamento da EXT-1 em células MV3 de melanoma (EXT-1kd),
levavam a um aumento da expressão do mRNA do receptor ativado por protease-1 (PAR-1), e
afetava a resistência ao fármaco Mitoxantrone. A desregulação do PAR-1, membro de uma
família de receptores membranares de sinalização conhecidos como receptores acoplados a
proteínas G (GPCRs), tem sido ligada ao desenvolvimento de vários tumores. Embora
numerosos estudos sugiram que os GPCR regulam uma vasta gama de processos relacionados
com o cancro, tais como o desenvolvimento dos tumores, migração e metástases, não existe
informação sobre como o PAR-1 causa quimiorreistência, embora se saiba que afeta várias
fases da metastização.
Neste trabalho exploramos se o aumento de expressão do PAR-1, após inibição da EXT-1, está
envolvido na resistência à quimioterapia nas células do melanoma MV3, e investigamos ainda
os mecanismos moleculares envolvidos neste processo.
Começámos por demonstrar que a EXT-1kd reduziu a quimiossensibilidade ao Mitoxantrone,
e que estas células estimulam uma agregação plaquetária mais rápida. Posteriormente,
confirmámos o aumento da forma ativa da proteína PAR-1 nesta linha celular. Além disso,
determinámos um valor de pEC50 mais elevado quanto as células EXT-1kd foram co-tratadas
com Mitoxantrone e BAY-386, um antagonista PAR-1, quando comparado com o valor obtido
com tratamento apenas com Mitoxantrone. Estes dados sugerem que a quimiorresistência das
células EXT-1kd é parcialmente dependente da atividade de PAR-1.
Embora os antagonistas PAR-1 estejam bem estabelecidos como medicamentos
antiplaquetários eficazes, a forma como funcionam no tratamento do cancro é ainda
desconhecida. O nosso trabalho mostra que os medicamentos que têm como alvo o receptor
PAR-1 poderão contribuir para reduzir a resistência à quimioterapia, abrindo assim novas vias
terapêuticas no tratamento do cancro.
Several human diseases are impacted by proteins of the Exostosin (EXT) family. Exostosin-1 (EXT-1), a member of the EXT protein family, is known to be essential to produce heparan sulphate chains, which bind to and influence the signalling effectiveness of a variety of growth factor activities. Unpublished research from our group demonstrated that EXT-1 knockdown in MV3 melanoma cells (EXT-1kd), leads to an increase in protease-activated receptor 1 (PAR 1) mRNA expression, and affects drug resistance to Mitoxantrone. Dysregulation of PAR-1, a member of a family of cell surface signalling receptors known as G-protein-coupled receptors (GPCRs), has been linked to several tumours. Although numerous studies suggest that GPCRs regulate a wide range of cancer-related processes, such as tumour development, migration, and metastasis, there is no information on how PAR-1 causes chemoresistance, even though it is known to affect several phases of metastasis. Herein, we explore if PAR-1 increased expression following EXT-1 knockdown underlies chemotherapy resistance in MV3 melanoma cells, and investigate the molecular mechanisms involved in this process. We began by demonstrating that EXT-1kd have reduced chemosensitivity to Mitoxantrone, and that these cells stimulate faster platelet aggregation. Afterwards we confirmed the increase in active form of PAR-1 protein in this cell line. Moreover, we determined that EXT-1kd cells present a higher pEC50 value when co-treated with Mitoxantrone plus BAY-386, a PAR-1 antagonist, when compared to a single treatment with Mitoxantrone. This data suggested that EXT-1kd chemoresistance is partially dependent on PAR-1 activity. Although PAR-1 antagonists are well established to be effective antiplatelet medications, how they work in treating cancer is still unknown. Our work shows that drugs that target PAR-1 contribute to reducing chemotherapy resistance in tumours, opening new therapeutic avenues in cancer treatment.
Several human diseases are impacted by proteins of the Exostosin (EXT) family. Exostosin-1 (EXT-1), a member of the EXT protein family, is known to be essential to produce heparan sulphate chains, which bind to and influence the signalling effectiveness of a variety of growth factor activities. Unpublished research from our group demonstrated that EXT-1 knockdown in MV3 melanoma cells (EXT-1kd), leads to an increase in protease-activated receptor 1 (PAR 1) mRNA expression, and affects drug resistance to Mitoxantrone. Dysregulation of PAR-1, a member of a family of cell surface signalling receptors known as G-protein-coupled receptors (GPCRs), has been linked to several tumours. Although numerous studies suggest that GPCRs regulate a wide range of cancer-related processes, such as tumour development, migration, and metastasis, there is no information on how PAR-1 causes chemoresistance, even though it is known to affect several phases of metastasis. Herein, we explore if PAR-1 increased expression following EXT-1 knockdown underlies chemotherapy resistance in MV3 melanoma cells, and investigate the molecular mechanisms involved in this process. We began by demonstrating that EXT-1kd have reduced chemosensitivity to Mitoxantrone, and that these cells stimulate faster platelet aggregation. Afterwards we confirmed the increase in active form of PAR-1 protein in this cell line. Moreover, we determined that EXT-1kd cells present a higher pEC50 value when co-treated with Mitoxantrone plus BAY-386, a PAR-1 antagonist, when compared to a single treatment with Mitoxantrone. This data suggested that EXT-1kd chemoresistance is partially dependent on PAR-1 activity. Although PAR-1 antagonists are well established to be effective antiplatelet medications, how they work in treating cancer is still unknown. Our work shows that drugs that target PAR-1 contribute to reducing chemotherapy resistance in tumours, opening new therapeutic avenues in cancer treatment.
Descrição
Trabalho Final de Mestrado Integrado, Ciências Farmacêuticas, 2022, Universidade de Lisboa, Faculdade de Farmácia.
Palavras-chave
Cancer Chemotherapy resistance Exostosin 1 Platelet aggregation Protease activated receptor (PAR-1) Mestrado integrado - 2022