Oportunidades de Dissertação

Instituição: NOVA Medical School, Universidade NOVA de Lisboa

Nome do Responsável: Duarte Barral

Contacto: duarte.barral@nms.unl.pt

Área de atuação: Lysosomal Exocytosis in Cancer Progression

Tema da Dissertação: Elucidating the Function of Lysosomal Exocytosis in Cancer Progression

Descrição da Dissertação: The elevated mortality rates associated with cancer are mainly due to the acquisition of  invasive capacity by cancer cells, enabling them to spread to distant organs and form metastases. As such, the development of novel therapies targeting cancer cell invasion and metastasis is crucial for mitigating cancer-related morbidity and mortality. In order to achieve this objective, it is essential to understand the molecular mechanisms governing cancer cell invasion and metastasis formation. Recent studies have revealed that various cancer cell types exhibit enhanced lysosome biogenesis, aberrant lysosome morphology and/or activity, and a redistribution of lysosomes from the perinuclear region to the cell periphery, resulting in increased lysosome exocytosis. This allows the release of lysosomal proteases to the extracellular milieu, enhancing extracellular matrix degradation and thus cancer progression, as well as drug resistance. While the association between lysosomal exocytosis and cancer progression is evident, the precise mechanisms controlling these processes remain to be fully elucidated. Further research in this area could potentially unveil novel therapeutic strategies to impair metastasis formation and enhance patient survival. Indeed, targeting lysosomal exocytosis or its regulatory pathways may offer promising avenues for cancer treatment, particularly in addressing invasiveness and chemoresistance in aggressive tumors. Therefore, we aim to: 1) Modulate lysosome exocytosis as a novel therapeutic strategy to impair cancer cell migration and invasion; 2) Establish new cancer diagnostic and prognostic biomarkers, based on the expression levels of lysosome exocytosis regulators. For this, lysosome exocytosis will be impaired in invasive cancers cell lines using genetic and pharmacological approaches. For the genetic approach (Task 1), we will silence known regulators of lysosome exocytosis, such as Rab small GTPases and other genes encoding proteins required for lysosome tethering, docking and fusion with the plasma membrane. In the pharmacological approach (Task 2), cancer cells will be incubated with compounds described to impair lysosome exocytosis. Lysosome exocytosis levels will be monitored by the presence of the lysosomal-associated membrane protein (LAMP)-1 at the cell surface, using flow cytometry, and by measuring the release of the lysosomal enzyme β-hexosaminidase to the culture medium, using an enzymatic assay. Then, we will evaluate cancer cell migration and invasion in 2D, using wound-healing and transwell assays, as well as in 3D, using spheroids (Task 3). Finally, we will use cancer patient samples to evaluate the expression levels of regulators of lysosome exocytosis by western blot and immunohistochemistry (Task 4). Thus, this project will allow us to test a new strategy to impair cancer cell invasiveness, which is an essential process in metastasis formation, and evaluate the use of lysosome exocytosis regulators as cancer biomarkers.

Período: Ano letivo 2025-2026.