Maria Helena Vasconcelos

Although glioblastoma stem cells (GSCs) constitute a small subpopulation of this highly heterogeneous brain cancer, they are widely recognised as key drivers of tumour recurrence after surgical resection and resistance to radiotherapy and chemotherapy. Differentiation of GSCs has, therefore, emerged as a strategy to increase glioblastoma susceptibility to therapeutic and surgical interventions. Cellular and molecular heterogeneity of glioblastoma limits the effectiveness of any treatment that relies on single molecules identified as disease-specific biomarkers. In this context, lipidomic and proteomic profiles constitute a source of information that can be translated into the identification of clinically relevant diagnostic and prognostic biomarkers, and novel therapeutic targets towards eradication of this lethal disease. Our initial studies demonstrated that BMP4 induced differentiation of the human glioblastoma stem cells G144 with approximately a 30-fold increase in expression of the astrocytic marker GFAP, which was coupled with a reduction in cell proliferation (33% decrease in EDU incorporation), invasion (61% decrease) and tumoursphere growth (53% decrease in area), and enhanced senescence-associated β-galactosidase activity (5.9-fold increase). Lipidomic and proteomic analysis (using data from 3 and 4 independent experiments, respectively) was then performed, allowing the identification of specific lipids and proteins exclusively detected or predominant in stem or differentiated G 144 cells. Importantly, our findings, which revealed a 6-fold increase in GFAP expression upon downregulation of a specific protein detected only in stem cells (SPRY4), pave the way for the employment of the RNAi-mediated knockdown strategy as a mechanistically distinct alternative to the use of BMP4, and highlight this protein as a candidate regulator associated with the G144 stem-like phenotype.

Bacterioruberin (BR), a C₅₀ carotenoid produced by halophilic archaea, is emerging as a bioactive molecule with potential anticancer relevance, but its activity in solid tumour and multidrug-resistant (MDR) models remains poorly defined. This in vitro study evaluated the cytotoxic, antiproliferative and growth-inhibitory effects of a chemically characterized bacterioruberin-rich carotenoid extract (BRCE) from Haloferax (H.) mediterranei in A549 lung adenocarcinoma, BT-549 triple-negative breast cancer and WM115 melanoma cells, as well as in paired sensitive/multidrug resistant (MDR) lung cancer models. Metabolic activity and proliferation were assessed by thiazolyl blue tetrazolium bromide (MTT) and carboxyfluorescein diacetate succinimidyl ester (CFDA-SE) assays, intracellular reactive oxygen species (ROS) by 2′,7′-dichlorodihydrofluorescein diacetate (H₂DCFDA) staining, and apoptosis-associated morphology by acridine orange/ethidium bromide (AO/EB) staining. Growth inhibition in A549/A549-CDR2 and NCI-H460/NCI-H460/R cells was analysed by sulforhodamine B (SRB) assay, while P-glycoprotein (P-gp) function and expression were examined using Rhodamine 123 (Rh123) accumulation and Western blotting. BRCE reduced metabolic activity and proliferation in a concentration- and time-dependent manner, increased intracellular ROS levels, and induced apoptosis-associated morphological changes in A549 cells. In MDR models, BRCE retained comparable growth-inhibitory activity in sensitive and resistant cells and partially attenuated P-gp-related drug efflux. These findings support further mechanistic investigation of BR in solid tumour and MDR cancer models.

Measurable residual disease (MRD) in acute myeloid leukemia (AML) is monitored through detection of leukemia-associated phenotypic protein markers (LAPMs) in bone marrow aspirates, hindering disease real-time monitoring. We explored peripheral blood (PB), extracellular vesicle (EV)-based methods for MRD monitoring. To confirm that LAPMs are present in AML-derived EVs, EVs were isolated from OCI-AML3 cells by differential centrifugation and characterized according to their size (nanoparticle tracking analysis), morphology (transmission electron microscopy) and protein cargo (proteomic analysis and Western blot). CD14 and CD33 were detected in OCI-AML3 cells and their released EVs. To select a method to isolate EVs from the PB of AML patients, three techniques were tested: size exclusion chromatography followed by ultrafiltration (SEC-UF), Total Exosome Isolation Kit (Invitrogen) and Exo-spin™ Exosome Purification Kit (Cell Guidance Systems). SEC-UF allowed EV isolation with higher purity and less aggregates than the other techniques. LAPMs were detected in those EVs, but their presence depended on the isolation method. Finally, EVs from seven AML patients’ plasma were isolated by SEC-UF. LAPMs were identified in paired samples at diagnosis and remission, with differential expression throughout disease evolution. This proof-of-concept study highlights the possibility of real-time MRD monitoring through LAPMs’ analysis in AML patient’s circulating EVs.

Aim: Non-small cell lung cancer (NSCLC) represents most lung cancer cases and remains associated with poor outcomes, mainly due to multidrug resistance (MDR). Extracellular vesicles (EVs) are crucial for intercellular communication and significantly influence chemotherapy resistance. This study aimed to characterize the EVs proteome of drug-sensitive and MDR NSCLC cell lines to identify therapeutic targets to counteract MDR. Methods: EVs derived from NSCLC cells were isolated by ultracentrifugation and analyzed for size by nanoparticle tracking analysis, for morphology by transmission electron microscopy, and for EVs markers by Western blotting (WB). Proteomic profiling was performed using liquid chromatography-mass spectrometry (LC-MS), followed by WB validation of relevant proteins. Cell growth and viability were assessed using sulforhodamine B or CellTiter-Glo assays. P-glycoprotein [P-gp, also known as ABCB1: adenosine triphosphate (ATP)-binding cassette subfamily B member 1] activity was determined by rhodamine-123 accumulation assay. SRC-related signaling was investigated by WB. Results: EVs from the multidrug resistant (MDR) derivative of NCI-H460, a human NSCLC cell line, displayed nine up- and eight down-regulated proteins compared with the drug-sensitive parental cells, including reduced SRC. WB results showed higher phosphorylated form of SRC (p-SRC) expression in MDR cells than in sensitive cells. In contrast, EVs from both cell lines had similar expression levels, suggesting selective intracellular retention in MDR cells. The SRC inhibitor bosutinib potentiated the activity of chemotherapeutics that are P-gp substrates in 2D and in 3D spheroids, without affecting the viability of the human lung fibroblast cell line MRC-5. Moreover, bosutinib reduced P-gp activity, likely by downregulating of phosphorylated caveolin-1. Conclusion: These findings show reduced selective packaging of p-SRC into EVs shed by MDR cells (MDR-EVs), suggesting an important role for this protein in the MDR phenotype and its potential as a molecular target. Bosutinib, an SRC inhibitor, might be useful as a chemosensitizer of MDR cells.

Background: Multiple myeloma (MM) is a complex hematological malignancy with heterogeneous clinical and pathophysiological backgrounds that influence treatment responses and outcomes. Identifying biomarkers to predict drug response and guide treatment decisions, particularly regarding drug combinations, is essential to improve therapeutic efficacy and patient outcomes. This study explores the role of microRNAs (miRNAs/miRs) derived from bone marrow (BM) and peripheral blood (PB) in responses to treatment and survival outcomes in newly diagnosed MM (ndMM) patients.Methods: This study included twenty patients with ndMM undergoing first-line treatment with bortezomib, thalidomide, and dexamethasone. The miRNAs were isolated from BM and PB, and their profiles were analyzed using Next-Generation Sequencing (NGS), followed by validation of differentially expressed miRNAs by quantitative real-time PCR (qPCR). Clinical and response data were collected to assess correlations between miRNA levels, clinical characteristics, and patient outcomes. In silico analysis for target-prediction and gene ontology (GO) enrichment was performed to explore the potential biological and functional role of the identified miRNAs.Results: NGS profiling revealed several miRNAs differently expressed between treatment-refractory and sensitive patients, as well as between PB and BM. Among these, miR-665, miR-483-5p, miR-143-3p and miR-145-5p were selected for further validation by qPCR. It was observed that miR-665 was significantly elevated in treatment-refractory patients compared to treatment-sensitive patients. Additionally, miR-665 levels were higher in PB than in BM. Elevated miR-665 levels were associated with more aggressive disease characteristics and poorer clinical outcomes, including reduced overall survival.Discussion: Our preliminary findings suggest that miR-665 could potentially serve as a non-invasive tool for predicting drug resistance and guiding treatment decisions in MM. These findings also highlight the potential utility of miRNAs in liquid biopsies as a predictive tool of drug response in MM and could pave the way for personalized treatment strategies, improving patient outcomes. Future research is needed to validate these results in larger cohorts and explore the underlying mechanisms of miR-665 in MM pathogenesis and drug resistance.

Non‐small cell lung cancer (NSCLC) shows limited therapeutic response to vinorelbine and carboplatin. Combining these drugs with an antifibrotic drug may enhance their antitumor effect. Pirfenidone is an antifibrotic drug whose antitumor activity has been described in different types of cancer. This work aimed to perform preclinical studies on the combination of pirfenidone with vinorelbine, or with vinorelbine plus carboplatin, in NSCLC. Our data revealed that pirfenidone sensitized three NSCLC cell lines to vinorelbine by reducing cell growth, viability and proliferation, inducing alterations in the cell cycle profile, and increasing cell death (%). Importantly, pirfenidone increased the sensitivity of the three NSCLC cell lines to the combined treatment of vinorelbine plus carboplatin. This combined drug treatment (triplet) did not induce cytotoxicity against non‐tumorigenic cells. Notably, the triplet drug combination significantly reduced the growth and proliferation of A‐549 xenografts in nude mice, as also reduced vimentin and collagen expression. Most interestingly, the triplet treatment exhibited a safer toxicological profile than the doublet (vinorelbine plus carboplatin) currently applied in the clinical practice. Altogether, these preclinical data support the possibility of repurposing pirfenidone in combination with vinorelbine or with vinorelbine plus carboplatin for NSCLC perioperative treatment, improving therapeutic efficacy while reducing toxicity.