Valés-Gómez, M. (Mar)

Filtering

2022 - 20232

Settings

Author search.filters.isAuthorOfPublication.e28ad91f-0cf5-49af-97b8-c1e52b09a26e

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    MAPK inhibitors dynamically affect melanoma release of immune NKG2D-ligands, as soluble protein and extracellular vesicle-associated
    (2023) Beneitez, A. (Alexandra); Paschen, A. (Annette); Alegre-Martinez, E. (Estibaliz); Valés-Gómez, M. (Mar); Tellez-Pérez, L. (Lucía); Gonzalez-Hernandez, A. (Alvaro); Sandúa-Condado, A. (Amaia); Pardo, M. (María); Lopez-Borrego, S. (Silvia); Camino, T. (Tamara); Jara-Acevedo, R. (Ricardo); Campos-Silva, C. (Carmen)
    Metastatic melanoma presents, in many cases, oncogenic mutations in BRAF, a MAPK involved in proliferation of tumour cells. BRAF inhibitors, used as therapy in patients with these mutations, often lead to tumour resistance and, thus, the use of MEK inhibitors was introduced in clinics. BRAFi/MEKi, a combination that has modestly increased overall survival in patients, has been proven to differentially affect immune ligands, such as NKG2D-ligands, in drug-sensitive vs. drug-resistant cells. However, the fact that NKG2D-ligands can be released as soluble molecules or in extracellular vesicles represents an additional level of complexity that has not been explored. Here we demonstrate that inhibition of MAPK using MEKi, and the combination of BRAFi with MEKi in vitro, modulates NKG2D-ligands in BRAF-mutant and WT melanoma cells, together with other NK activating ligands. These observations reinforce a role of the immune system in the generation of resistance to directed therapies and support the potential benefit of MAPK inhibition in combination with immunotherapies. Both soluble and EV-associated NKG2D-ligands, generally decreased in BRAF-mutant melanoma cell supernatants after MAPKi in vitro, replicating cell surface expression. Because potential NKG2D-ligand fluctuation during MAPKi treatment could have different consequences for the immune response, a pilot study to measure NKG2D-ligand variation in plasma or serum from metastatic melanoma patients, at different time points during MAPKi treatment, was performed. Not all NKG2D-ligands were equally detected. Further, EV detection did not parallel soluble protein. Altogether, our data confirm the heterogeneity between melanoma lesions, and suggest testing several NKG2D-ligands and other melanoma antigens in serum, both as soluble or vesicle-released proteins, to help classifying immune competence of patients.
  • Thumbnail Image
    A simple immunoassay for extracellular vesicle liquid biopsy in microliters of non‑processed plasma
    (2022) Beneitez, A. (Alexandra); Sánchez-Herrero, E. (Estela); Valés-Gómez, M. (Mar); Gonzalez-Hernandez, A. (Alvaro); Romero, A. (A.); Provencio, M. (Mariano); Jara-Acevedo, R. (Ricardo); Yáñez-Mó, M. (María); Campos-Silva, C. (Carmen)
    Background: Extracellular vesicles (EVs), released by most cell types, provide an excellent source of biomarkers in biological fluids. However, in order to perform validation studies and screenings of patient samples, it is still necessary to develop general techniques permitting rapid handling of small amounts of biological samples from large numbers of donors. Results: Here we describe a method that, using just a few microliters of patient’s plasma, identifies tumour markers exposed on EVs. Studying physico-chemical properties of EVs in solution, we demonstrate that they behave as stable colloidal suspensions and therefore, in immunocapture assays, many of them are unable to interact with a stationary functionalised surface. Using flocculation methods, like those used to destabilize colloids, we demonstrate that cationic polymers increase EV ζ-potential, diameter, and sedimentation coefficient and thus, allow a more efficient capture on antibody-coated surfaces by both ELISA and bead-assisted flow cytometry. These findings led to optimization of a protocol in microtiter plates allowing effective immunocapture of EVs, directly in plasma without previous ultracentrifugation or other EV enrichment. The method, easily adaptable to any laboratory, has been validated using plasma from lung cancer patients in which the epithelial cell marker EpCAM has been detected on EVs. Conclusions: This optimized high throughput, easy to automate, technology allows screening of large numbers of patients to phenotype tumour markers in circulating EVs, breaking barriers for the validation of proposed EV biomarkers and the discovery of new ones.