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Biology subjects

Dias, D.

Publications and source records attributed to Dias, D..

9 recordsLinked to original sources

Selective scoring of drug effects in multicellular co-culture systems

Multicellular co-culture screening reveals compound effects that depend on cell-cell interactions. Standard dose-response metrics fail to resolve effects that arise either from target-effector cell interactions or from non-specific toxic effects. Here, we developed Co-culture Efficacy Score (CES), a robust computational framework that enables systematic identification of compounds that selectively modulate cellular interactions in multicellular assays. CES framework supports both therapeutic scoring that penalizes direct effector cell toxicity, as well as a mechanistic discovery that estimates immunomodulatory effects by adjusting for effector cell responses. When screening 527 compounds across 10 hematological cancer models co-cultured with natural killer (NK) cells, CES distinguished co-culture-specific immunomodulatory effects from NK cell toxicity and cancer cell inhibitory responses, recovering systematic enhancer and inhibitory patterns. We further assessed CES robustness using higher-resolution validation screens and demonstrated its applicability to identify selective compounds in anti-CD19 CAR T-cell and antiviral host-pathogen screens. To facilitate its broad use, we implemented CES as an interactive web-application for quantitative analysis of compound responses in co-culture assays, providing a widely applicable scoring framework for cancer immunotherapy, antiviral screening and drug discovery.

bioinformatics↗

Multimodal immunopharmacologic screens identify drugs rewiring the cancer-immune interface

Natural killer (NK) cell-based therapies are a promising approach in cancer, but their efficacy is limited by impaired effector function and tumor-intrinsic resistance. To systematically identify therapeutic strategies that target both sides of the cancer-immune interface, we designed a multimodal immunopharmacologic screening platform comprising high-throughput co-culture drug screens, cytokine secretome profiling, single-cell perturbation screens, and genome-scale CRISPR screening, followed by validation in biobanked patient-derived models. Applying the platform across five blood cancer types, we identified protein kinase C (PKC) activation to simultaneously increase effector cytotoxicity and cytokine secretion through transcriptomic rewiring, and tumor susceptibility to NK cell killing through tumor-intrinsic PKC-{delta}. In patient samples, PKC activation sensitized NK-resistant leukemic progenitors to NK cell killing. In addition, NEDD8 inhibition enhanced NK function and shifted tumor TNF signaling towards pro-apoptotic pathways. Our platform provides a systematic approach to identify drugs rewiring both sides of the cancer-immune interface to circumvent tumor immune resistance.

cancer biology↗

A statistical framework for defining synergistic anticancer drug interactions

Synergistic drug combinations have the potential to delay drug resistance and improve clinical outcomes in patients with advanced cancers. However, current cell-based screens lack robust statistical assessment to identify significant synergistic interactions for downstream experimental or clinical validation. Leveraging a large-scale dataset that systematically evaluated more than 2,000 drug combinations across 125 pan-cancer cell lines, we established reference null distributions separately for various synergy metrics and cancer types. These data-driven reference distributions enable estimation of empirical p-values to assess the significance of observed drug combination effects, thereby standardizing synergy detection in future studies. The statistical evaluation confirmed key synergistic combinations and uncovered novel combination effects that met stringent statistical criteria, yet were overlooked in the original analyses. We revealed cell context-specific drug combination effects across tissue types and inherent differences in statistical behavior of the synergy metrics. To demonstrate the general applicability of our approach to smaller-scale studies, we applied it to evaluate the significance of combination effects in increasing smaller subsamples of an independent dataset. We provide a fast and statistically rigorous approach to detecting synergistic drug interactions in new combinatorial screens, thereby supporting more standardized drug combination discovery.

bioinformatics↗

Freshwater fish community assessment using eDNA metabarcoding vs. capture-based methods: differences in efficiency and resolution coupled to habitat and ecology

Environmental DNA (eDNA) metabarcoding has revolutionized ecological and environmental research by describing communities without relying on direct observations, making it a powerful, non-invasive, and cost-effective tool in biodiversity monitoring. However, implementation of eDNA as a standard protocol in long-term monitoring programs, that have traditionally relied on capture-based methods, poses challenges in terms of data comparability. Here, we compared freshwater fish communities assessed through eDNA metabarcoding and electrofishing, across 35 sampling sites in the lower Tagus River basin, Portugal. For most species or species-groups analyzed individually (13 out of 17), there was a significant correspondence between electrofishing and eDNA metabarcoding detections. The correspondence was weaker when comparing the number of specimens captured by electrofishing with the number of eDNA metabarcoding reads, with seven out of 13 taxa showing significant relationships. Species richness estimates based on the two methods were very similar at the basin level. The methods yielded significantly different species compositions, although these differences were driven by samples collected in the Tagus main channel, which is wider and has higher flow rates than tributaries. Benthic and shoreline fish communities showed similar species composition in the two methods, but this was not the case for pelagic communities, probably due to the higher water turnover of the pelagic zone and electrofishing inefficiency. Our results highlight the high potential of eDNA metabarcoding as a complementary method to electrofishing for freshwater fish monitoring, though further validation is needed to assess biases related to site-specific hydrological conditions and the ecology of the target species.

ecology↗

Scaling up drug combination surface prediction

Drug combinations are required to treat advanced cancers and other complex diseases. Compared to monotherapy, combination treatments can enhance efficacy and reduce toxicity by lowering the doses of single drugs - and there especially synergistic combinations are of interest. Since drug combination screening experiments are costly and time consuming, reliable machine learning models are needed for prioritizing potential combinations for further studies. Most of the current machine learning models are based on scalar-valued approaches, which predict individual response values or synergy scores for drug combinations. We take a functional output prediction approach, in which full, continuous dose-response combination surfaces are predicted for each drug combination on the cell lines. We investigate the predictive power of the recently proposed comboKR method, which is based on a powerful input-output kernel regression technique and functional modelling of the response surface. In this work, we develop a scaled-up formulation of the comboKR, that also implements improved modeling choices: 1) we incorporate new modeling choices for the output drug combination response surfaces to the comboKR framework, and 2) propose a projected gradient descent method to solve the challenging pre-image problem that traditionally is solved with simple candidate set approaches. We provide thorough experimental analysis of comboKR 2.0 with three real-word datasets within various challenging experimental settings, including cases where drugs or cell lines have not been encountered in the training data. Our comparison with synergy score prediction methods further highlights the relevance of dose-response prediction approaches, instead of relying on simple scoring methods.

bioinformatics↗

Functional specialization of MITF, TFEB and TFE3 drives radically distinct adaptive gene expression programs in melanoma.

Cells can contain multiple related transcription factors targeting the same sequences, leading to potential regulatory cooperativity, redundancy, competition or temporally regulated factor exchange. Yet the differential biological functions of co-targeting transcription factors are poorly understood. In melanoma, three highly related transcription factors are co-expressed: The mTORC1-regulated TFEB and TFE3, key effectors of a wide range of metabolic and microenvironmental cues assumed to perform similar functions; and MITF, that controls melanoma phenotypic identity. Here we reveal the functional specialization of MITF, TFE3 and TFEB and their impact on melanoma progression. Notably, although all bind the same sequences, each regulates different and frequently opposing gene expression programs to coordinate differentiation, metabolism, and protein synthesis, and qualitatively and quantitatively impact tumor immune infiltration. The results uncover a hierarchical cascade whereby microenvironmental stresses, including glucose limitation, lead MITF, TFEB and TFE3 to drive distinct biologically important transcription programs that underpin phenotypic transitions in cancer.

cancer biology↗

Reproductive traits of the European catfish (Silurus glanis) during the early stages of invasion in the Lower Tagus River

Freshwater ecosystems face severe challenges from biological invasions, leading to biodiversity loss, disruption of ecosystem services, and economic impacts. Human-mediated activities, such as aquarium trade and sport angling, contribute to species introductions, with potential negative consequences for native ecosystems. The European catfish (Silurus glanis) is one of the worlds largest freshwater fish and has been intentionally introduced into diverse regions, impacting native ecosystems. However, limited research exists on its reproductive traits outside its native range. This study addresses this gap by examining the reproductive characteristics of non-native European catfish populations in the Lower Tagus River in Portugal, focusing on size at maturity, spawning period, and fecundity. The observed balanced sex ratio aligns with studies of native populations. Variations in size at first maturity (TL50) among populations highlight the influence of habitat conditions, temperature, food availability, growth rate, and geographical location on this trait. The extended spawning season (March to June) in the Tagus River is consistent with native populations, but variations may occur based on environmental conditions and water temperature. Absolute fecundity ranged from 8,961 to 335,500 oocytes, showing positive relationships with body size and emphasizing the reproductive potential of European catfish in Portugal. Egg size variations, along with asynchronous egg development, contribute to the species reproductive strategy, favoring its invasive success. Management efforts should include monitoring, regulations on introductions, removal programs, and public awareness to mitigate their impact. Future research should focus on understanding how non-native European catfish populations adapt in various regions and continue to impact ecosystems.

ecology↗

DNA damage-induced interaction between a lineage addiction oncogenic transcription factor and the MRN complex shapes a tissue-specific DNA Damage Response and cancer predisposition

Since genome instability can drive cancer initiation and progression, cells have evolved highly effective and ubiquitous DNA Damage Response (DDR) programs. However, some cells, in skin for example, are normally exposed to high levels of DNA damaging agents. Whether such high-risk cells possess lineage-specific mechanisms that tailor DNA repair to the tissue remains largely unknown. Here we show, using melanoma as a model, that the microphthalmia-associated transcription factor MITF, a lineage addition oncogene that coordinates many aspects of melanocyte and melanoma biology, plays a non-transcriptional role in shaping the DDR. On exposure to DNA damaging agents, MITF is phosphorylated by ATM/DNA-PKcs, and unexpectedly its interactome is dramatically remodelled; most transcription (co)factors dissociate, and instead MITF interacts with the MRE11-RAD50-NBS1 (MRN) complex. Consequently, cells with high MITF levels accumulate stalled replication forks, and display defects in homologous recombination-mediated repair associated with impaired MRN recruitment to DNA damage. In agreement, high MITF levels are associated with increased SNV burden in melanoma. Significantly, the SUMOylation-defective MITF-E318K melanoma predisposition mutation recapitulates the effects of ATM/DNA-PKcs-phosphorylated MITF. Our data suggest that a non-transcriptional function of a lineage-restricted transcription factor contributes to a tissue-specialised modulation of the DDR that can impact cancer initiation.

molecular biology↗

Westwards expansion of the European catfish Silurus glanis in the Douro River (Portugal)

The current study reports the first occurrence and the spread of the European catfish Silurus glanis (Family: Siluridae) in the Portuguese section of the Douro River, suggesting a potential expansion of its distribution in Portugal either via westward dispersal across international rivers and/or human-assisted introductions into new reservoirs and drainages. European catfish has unique features (e.g., opportunistic predator, hunting, and aggregation behaviour) that make it highly suitable for establishing self-sustaining populations in new areas and likely contribute to its invasion success. The species may severely affect native prey communities and modify food web structure and ecosystem functioning. Efficient and sustainable management actions are needed to prevent further introductions in the future.

ecology↗