Drug-Induced Reorganisation of Lipid Metabolism Limits the Therapeutic Efficacy of Ponatinib in Glioma Stem Cells.

The standard of care for glioblastoma (GBM) involves surgery followed by adjuvant radio- and chemotherapy, but often within months, patients relapse, and this has been linked to glioma stem cells (GSCs), self-renewing cells with increased therapy resistance. The identification of the epidermal growth factor receptor (EGFR) and platelet-derived growth factor receptor (PDGFR) as key players in gliomagenesis inspired the development of inhibitors targeting these tyrosine kinases (TKIs). However, results from clinical trials testing TKIs have been disappointing, and while the role of GSCs in conventional therapy resistance has been extensively studied, less is known about resistance of GSCs to TKIs. In this study, we have used compartmentalised proteomics to analyse the adaptive response of GSCs to ponatinib, a TKI with activity against PDGFR. The analysis of differentially expressed proteins revealed that GSCs respond to ponatinib by broadly rewiring lipid metabolism, involving fatty acid beta-oxidation, cholesterol synthesis, and sphingolipid degradation. Inhibiting each of these metabolic pathways overcame ponatinib adaptation of GSCs, but interrogation of patient data revealed sphingolipid degradation as the most relevant pathway in GBM. Our data highlight that targeting lipid metabolism, and particularly sphingolipid degradation in combinatorial therapies, could improve the outcome of TKI therapies using ponatinib in GBM.

Identification of structurally diverse FSP1 inhibitors that sensitize cancer cells to ferroptosis.

Ferroptosis is a regulated form of cell death associated with the iron-dependent accumulation of phospholipid hydroperoxides. Inducing ferroptosis is a promising approach to treat therapy-resistant cancer. Ferroptosis suppressor protein 1 (FSP1) promotes ferroptosis resistance in cancer by generating the antioxidant form of coenzyme Q10 (CoQ). Despite the important role of FSP1, few molecular tools exist that target the CoQ-FSP1 pathway. Through a series of chemical screens, we identify several structurally diverse FSP1 inhibitors. The most potent of these compounds, ferroptosis sensitizer 1 (FSEN1), is an uncompetitive inhibitor that acts selectively through on-target inhibition of FSP1 to sensitize cancer cells to ferroptosis. Furthermore, a synthetic lethality screen reveals that FSEN1 synergizes with endoperoxide-containing ferroptosis inducers, including dihydroartemisinin, to trigger ferroptosis. These results provide new tools that catalyze the exploration of FSP1 as a therapeutic target and highlight the value of combinatorial therapeutic regimes targeting FSP1 and additional ferroptosis defense pathways.

The Regulators of Peroxisomal Acyl-Carnitine Shuttle CROT and CRAT Promote Metastasis in Melanoma.

Circulating tumor cells are the key link between a primary tumor and distant metastases, but once in the bloodstream, loss of adhesion induces cell death. To identify the mechanisms relevant for melanoma circulating tumor cell survival, we performed RNA sequencing and discovered that detached melanoma cells and isolated melanoma circulating tumor cells rewire lipid metabolism by upregulating fatty acid (FA) transport and FA beta-oxidation‒related genes. In patients with melanoma, high expression of FA transporters and FA beta-oxidation enzymes significantly correlates with reduced progression-free and overall survival. Among the highest expressed regulators in melanoma circulating tumor cells were the carnitine transferases carnitine O-octanoyltransferase and carnitine acetyltransferase, which control the shuttle of peroxisome-derived medium-chain FAs toward mitochondria to fuel mitochondrial FA beta-oxidation. Knockdown of carnitine O-octanoyltransferase or carnitine acetyltransferase and short-term treatment with peroxisomal or mitochondrial FA beta-oxidation inhibitors thioridazine or ranolazine suppressed melanoma metastasis in mice. Carnitine O-octanoyltransferase and carnitine acetyltransferase depletion could be rescued by medium-chain FA supplementation, indicating that the peroxisomal supply of FAs is crucial for the survival of nonadherent melanoma cells. Our study identifies targeting the FA-based cross-talk between peroxisomes and mitochondria as a potential therapeutic opportunity to challenge melanoma progression. Moreover, the discovery of the antimetastatic activity of the Food and Drug Administration‒approved drug ranolazine carries translational potential.

Metabolic rewiring induced by ranolazine improves melanoma responses to targeted therapy and immunotherapy.

Resistance of melanoma to targeted therapy and immunotherapy is linked to metabolic rewiring. Here, we show that increased fatty acid oxidation (FAO) during prolonged BRAF inhibitor (BRAFi) treatment contributes to acquired therapy resistance in mice. Targeting FAO using the US Food and Drug Administration-approved and European Medicines Agency-approved anti-anginal drug ranolazine (RANO) delays tumour recurrence with acquired BRAFi resistance. Single-cell RNA-sequencing analysis reveals that RANO diminishes the abundance of the therapy-resistant NGFRhi neural crest stem cell subpopulation. Moreover, by rewiring the methionine salvage pathway, RANO enhances melanoma immunogenicity through increased antigen presentation and interferon signalling. Combination of RANO with anti-PD-L1 antibodies strongly improves survival by increasing antitumour immune responses. Altogether, we show that RANO increases the efficacy of targeted melanoma therapy through its effects on FAO and the methionine salvage pathway. Importantly, our study suggests that RANO could sensitize BRAFi-resistant tumours to immunotherapy. Since RANO has very mild side-effects, it might constitute a therapeutic option to improve the two main strategies currently used to treat metastatic melanoma.

Efficacy and safety of anti-PD-1/PD-L1 combinations versus standard of care in cancer: a systematic review and meta-analysis.

Immune checkpoint inhibitors (ICIs) as monotherapy in different solid tumors showed an early detrimental effect in a subset of patients reflected by the early crossover of the progression-free survival (PFS) curves. Currently, combination therapies with ICIs added to chemotherapy or targeted therapy are expanding the landscape of metastatic solid tumors. We have examined the benefits and risks of adding ICIs to the standard of care (SOC) versus SOC alone. A search of randomized clinical trials (RCTs) comparing ICIs combinations versus the corresponding SOC in different metastatic tumors according to the PRISMA guidelines was performed. Selected endpoints included PFS, time-to-response (TTR), overall survival (OS), overall response rate (ORR), and ≥ grade 3 adverse events (AEs). Subgroup analyses based on backbone treatment and tumor type were included. A total of 10536 patients (19 studies) were included (ICIs-arm: 5596 patients; SOC-arm: 4940 patients). Globally, PFS, OS, and ORR results favored ICIs-arm. No differences in terms of TTR were found between arms. ICI-arm was associated with a slight increase of ≥ G3 AEs (relative risk: 1.07). The results in multiple myeloma patients are controversial in favor of ICIs combinations. Adding ICIs to SOC benefits a greater number of patients, prolonging survival with no early detrimental effect. The toxicity profile is safe, with a mild increase of high-grade manageable AEs.

[COVID-19 incidence in districts of Madrid and its relationship with socio-economic and demographic indicators.] / Incidencia de COVID-19 en distritos de Madrid y su relación con indicadores socioeconómicos y demográficos.

OBJECTIVE: The preventive measures to be taken in the face of a new epidemic require knowledge of the number of infected and which groups are most vulnerable. To know the cumulative incidence of COVID-19 in the city of Madrid and its 21 districts in the first 4 months of the epidemic and its relationship with some socioeconomic and demographic variables. METHODS: Cross-sectional ecological study (39,270 cases). The 39,270 cases diagnosed from the beginning of the pandemic until June 26, 2020, published by the Comunidad de Madrid in were studied. In the districts, the distribution of gross and fair incidence is related to the ones of the independent variables (Municipal Statistics and Estudio de Salud 2018, Madrid Salud). The Incidence and the r and r2 coefficients, obtained with the factors and the Multiple Linear Regression (MLR) model, are studied. RESULTS: The city of Madrid presents a cumulative incidence of COVID-19, which is double the national one (100), with a Standardized Cumulative Incidence Ratio (RIAE) of 204.59 per 100. The districts with the most RIAE were those in the southeast, all>240 per 100. In the districts, the per capita household rate, the per capita income, and the mortality rate from infectious diseases in men reached high and inverse correlations with RIAE (all r>-0.3). The RLM model with these 3 indicators predicts 30% of the RIAES. CONCLUSIONS: The relationship between material wealth and the risk of COVID-19 infection is inverse. The knowledge in the districts of per capita income, household rate and mortality rate due to infectious diseases in men reduces the uncertainty about the accumulated incidence by 30%.

OBJETIVO: Las medidas preventivas a tomar ante una nueva epidemia requieren conocimiento del número de infectados y de qué grupos son más vulnerables. El objetivo de este trabajo fue conocer la Incidencia Acumulada de COVID-19 en la ciudad de Madrid y sus 21 distritos en los 4 primeros meses de la epidemia y su relación con algunas variables socioeconómicas y demográficas. METODOS: Estudio ecológico transversal. Se estudiaron los 39.270 casos diagnosticados desde el inicio de la pandemia hasta el 26 de junio de 2020, publicados por la Comunidad de Madrid agregadamente. Se relacionó la distribución de la incidencia acumulada en los 21 distritos con la de algunas variables demográficas, socioeconómicas y de salud. Se estudiaron los coeficientes r y r2 que se calcularon con los factores y el modelo obtenido según Regresión Lineal Múltiple (RLM). RESULTADOS: La ciudad de Madrid presentó el doble de la incidencia acumulada (IA) de COVID-19 que la nacional (100), con una Razón de Incidencia Acumulada Estandarizada (RIAE) de 204,59 por 100, destacando los distritos del sureste, todos con IA mayores a 240 por 100. La Tasa de hogares por habitante, la Renta per cápita y la Tasa de Mortalidad por Enfermedades infecciosas en hombres alcanzaron en los distritos correlaciones altas e inversas con RIAE (todos r>-0,3). El modelo RLM con esos 3 indicadores predijo un 30% de las RIAES. CONCLUSIONES: La relación entre riqueza material agregada y riesgo de infección por COVID-19 es inversa. El conocimiento de renta, tasa de hogares y tasa mortalidad por enfermedades infecciosas en hombres disminuyó un 30% la incertidumbre sobre la incidencia acumulada en los distritos.

Identification of a Dexamethasone Mediated Radioprotection Mechanism Reveals New Therapeutic Vulnerabilities in Glioblastoma.

(1) Background: Despite the indisputable effectiveness of dexamethasone (DEXA) to reduce inflammation in glioblastoma (GBM) patients, its influence on tumour progression and radiotherapy response remains controversial. (2) Methods: We analysed patient data and used expression and cell biological analyses to assess effects of DEXA on GBM cells. We tested the efficacy of tyrosine kinase inhibitors in vitro and in vivo. (3) Results: We confirm in our patient cohort that administration of DEXA correlates with worse overall survival and shorter time to relapse. In GBM cells and glioma stem-like cells (GSCs) DEXA down-regulates genes controlling G2/M and mitotic-spindle checkpoints, and it enables cells to override the spindle assembly checkpoint (SAC). Concurrently, DEXA up-regulates Platelet Derived Growth Factor Receptor (PDGFR) signalling, which stimulates expression of anti-apoptotic regulators BCL2L1 and MCL1, required for survival during extended mitosis. Importantly, the protective potential of DEXA is dependent on intact tyrosine kinase signalling and ponatinib, sunitinib and dasatinib, all effectively overcome the radio-protective and pro-proliferative activity of DEXA. Moreover, we discovered that DEXA-induced signalling creates a therapeutic vulnerability for sunitinib in GSCs and GBM cells in vitro and in vivo. (4) Conclusions: Our results reveal a novel DEXA-induced mechanism in GBM cells and provide a rationale for revisiting the use of tyrosine kinase inhibitors for the treatment of GBM.

Cooperative behaviour and phenotype plasticity evolve during melanoma progression.

A major challenge for managing melanoma is its tumour heterogeneity based on individual co-existing melanoma cell phenotypes. These phenotypes display variable responses to standard therapies, and they drive individual steps of melanoma progression; hence, understanding their behaviour is imperative. Melanoma phenotypes are defined by distinct transcriptional states, which relate to different melanocyte lineage development phases, ranging from a mesenchymal, neural crest-like to a proliferative, melanocytic phenotype. It is thought that adaptive phenotype plasticity based on transcriptional reprogramming drives melanoma progression, but at which stage individual phenotypes dominate and moreover, how they interact is poorly understood. We monitored melanocytic and mesenchymal phenotypes throughout melanoma progression and detected transcriptional reprogramming at different stages, with a gain in mesenchymal traits in circulating melanoma cells (CTCs) and proliferative features in metastatic tumours. Intriguingly, we found that distinct phenotype populations interact in a cooperative manner, which generates tumours of greater "fitness," supports CTCs and expands organotropic cues in metastases. Fibronectin, expressed in mesenchymal cells, acts as key player in cooperativity and promotes survival of melanocytic cells. Our data reveal an important role for inter-phenotype communications at various stages of disease progression, suggesting these communications could act as therapeutic target.

Comparative safety analysis of immunotherapy combined with chemotherapy versus monotherapy in solid tumors: a meta-analysis of randomized clinical trials.

Background: Combination treatment (chemotherapy plus immune checkpoint blockade [ICB]) has shown promising activity in terms of efficacy, but it has been suggested that its toxicity profile is less favorable compared to monotherapy. Methods: We conducted a meta-analysis of published randomized clinical trials comparing combination treatment to monotherapy (chemotherapy or ICB) in patients with metastatic solid tumors. Differences in rates of safety issues (all-grade adverse events, grade 3/4 adverse events, treatment-related deaths, treatment discontinuations) between groups were estimated. Subgroup analyses for the control group (chemotherapy or ICB as monotherapy) and immune checkpoint inhibitor (anti-CTLA-4 or anti-PD-1/PD-L1 antibodies) were performed. Results: A total of 4379 patients (ten studies) were included (monotherapy: 2026 patients; combination treatment: 2353 patients). Combination treatment presented more grade 3/4 adverse events (RR 1.32, 95% CI 1.12-1.55) and discontinuations (RR 2.31, 95% CI 1.28-4.16). There were no differences in the mortality rate between groups. Subgroup analyses showed a potentially more toxic profile with anti-CTLA-4 agents. Conclusions: Combination treatment is associated with an increase in grade 3/4 adverse events and treatment discontinuations compared to monotherapy, but not increased mortality. The toxicity profile of combination therapy should be considered with regard to the overlapping safety profiles.

CDK4/6 Inhibitor as a Novel Therapeutic Approach for Advanced Bladder Cancer Independently of RB1 Status.

PURPOSE: Bladder cancer is a clinical and social problem due to its high incidence and recurrence rates. It frequently appears in elderly patients showing other medical comorbidities that hamper the use of standard chemotherapy. We evaluated the activity of CDK4/6 inhibitor as a new therapy for patients unfit for cisplatin (CDDP). EXPERIMENTAL DESIGN: Bladder cancer cell lines were tested for in vitro sensitivity to CDK4/6 inhibition. A novel metastatic bladder cancer mouse model was developed and used to test its in vivo activity. RESULTS: Cell lines tested were sensitive to CDK4/6 inhibition, independent on RB1 gene status. Transcriptome analyses and knockdown experiments revealed a major role for FOXM1 in this response. CDK4/6 inhibition resulted in reduced FOXM1 phosphorylation in vitro and in vivo and showed synergy with CDDP, allowing a significant tumor regression. FOXM1 exerted important oncogenic roles in bladder cancer. CONCLUSIONS: CDK4/6 inhibitors, alone or in combination, are a novel therapeutic strategy for patients with advanced bladder cancer previously classified as unfit for current treatment options.

Exosomes: Definition, Role in Tumor Development and Clinical Implications.

Exosomes are microvesicles released by cells in both physiological and pathological situations. They are surrounded by a lipid bilayer with proteins derived from the origin cell, and contain a variety of molecules, such as nucleic acids. They represent an emerging mechanism of intercellular communication, and they play an important role in the pathogenesis of cancer, stimulating proliferation and aggressiveness of cancer cells, inducing a microenvironment favorable to tumor development and controlling immune responses. Because of the growing understanding of the potential implications of extracellular vesicles in the development of malignancies, research on exosomes, and its role as a diagnostic and therapeutic tool, constitutes nowadays a very exciting and promising field.

Urothelial cancer proteomics provides both prognostic and functional information.

Traditionally, bladder cancer has been classified based on histology features. Recently, some works have proposed a molecular classification of invasive bladder tumors. To determine whether proteomics can define molecular subtypes of  muscle invasive urothelial cancer (MIUC) and allow evaluating the status of biological processes and its clinical value. 58 MIUC patients who underwent curative surgical resection at our institution between 2006 and 2012 were included. Proteome was evaluated by high-throughput proteomics in routinely archive FFPE tumor tissue. New molecular subgroups were defined. Functional structure and individual proteins prognostic value were evaluated and correlated with clinicopathologic parameters. 1,453 proteins were quantified, leading to two MIUC molecular subgroups. A protein-based functional structure was defined, including several nodes with specific biological activity. The functional structure showed differences between subtypes in metabolism, focal adhesion, RNA and splicing nodes. Focal adhesion node has prognostic value in the whole population. A 6-protein prognostic signature, associated with higher risk of relapse (5 year DFS 70% versus 20%) was defined. Additionally, we identified two MIUC subtypes groups. Prognostic information provided by pathologic characteristics is not enough to understand MIUC behavior. Proteomics analysis may enhance our understanding of prognostic and classification. These findings can lead to improving diagnosis and treatment selection in these patients.