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Simple Summary: Treatment of relapsed or metastatic rhabdomyosarcoma (RMS) has low survival rates due to resistance mechanisms. In this work, experiments were undertaken to identify potential druggable pathways involved in radiotherapy resistance. We found that prolonged activation of a protein network formed by Akt1, Src, and caveolin-1 (Cav1) lowers intracellular reactive oxygen species (ROS) levels through the acquisition of high catalase expression, conferring radioresistance to RMS cells. Treatment of radioresistant cells with statins, drugs used worldwide for the treatment of hypercholesterolemia, significantly attenuated the Akt1/Cav1 signaling and radioresistance mechanisms through increased cell apoptosis. This evidence suggests that administration of statins could help to improve the success of radiotherapy in RMS. Identifying the molecular mechanisms underlying radioresistance is a priority for the treatment of RMS, a myogenic tumor accounting for approximately 50% of all pediatric soft tissue sarcomas. We found that irradiation (IR) transiently increased phosphorylation of Akt1, Src, and Cav1 in human RD and RH30 lines. Synthetic inhibition of Akt1 and Src phosphorylation increased ROS levels in all RMS lines, promoting cellular radiosensitization. Accordingly, the elevated activation of the Akt1/Src/Cav1 pathway, as detected in two RD lines characterized by overexpression of a myristoylated Akt1 form (myrAkt1) or Cav1 (RDCav1), was correlated with reduced levels of ROS, higher expression of catalase, and increased radioresistance. We found that treatment with cholesterol-lowering drugs such as lovastatin and simvastatin promoted cell apoptosis in all RMS lines by reducing Akt1 and Cav1 levels and increasing intracellular ROS levels. Combining statins with IR significantly increased DNA damage and cell apoptosis as assessed by γ histone 2AX (γH2AX) staining and FACS analysis. Furthermore, in combination with the chemotherapeutic agent actinomycin D, statins were effective in reducing cell survival through increased apoptosis. Taken together, our findings suggest that the molecularly linked signature formed by Akt1, Src, Cav1, and catalase may represent a prognostic determinant for identifying subgroups of RMS patients with higher probability of recurrence after radiotherapy. Furthermore, statin-induced oxidative stress could represent a treatment option to improve the success of radiotherapy. [ABSTRACT FROM AUTHOR]

Background and Purpose: Fenretinide, a synthetic retinoid derivative first investigated for cancer prevention and treatment, has been shown to ameliorate glucose tolerance, improve plasma lipid profile and reduce body fat mass. These effects, together with its ability to inhibit ceramide synthesis, suggest that fenretinide may have an anti-atherosclerotic action.Experimental Approach: To this aim, nine-week-old apoE-knockout (EKO) female mice were fed for twelve weeks a Western diet, without (control) or with (0.1% w/w) fenretinide. As a reference, wild-type (WT) mice were treated similarly. Growth and metabolic parameters were monitored throughout the study. Atherosclerosis development was evaluated in the aorta and at the aortic sinus. Blood and lymphoid organs were further characterized with thorough cytological/histological and immunocytofluorimetric analyses.Key Results: Fenretinide treatment significantly lowered body weight, glucose levels and plasma levels of total cholesterol, triglycerides, and phospholipids. In the liver, fenretinide remarkably reduced hepatic glycogenosis and steatosis driven by the Western diet. Treated spleens were abnormally enlarged, with severe follicular atrophy and massive extramedullary haematopoiesis. Severe renal hemosiderin deposition was observed in treated EKO mice. Treatment resulted in a threefold increase of total leukocytes (WT and EKO) and raised the activated/resting monocyte ratio in EKO mice. Finally, atherosclerosis development was markedly increased at the aortic arch, thoracic and abdominal aorta of fenretinide-treated mice.Conclusions and Implications: We provide the first evidence that, despite beneficial metabolic effects, fenretinide treatment may enhance the development of atherosclerosis. [ABSTRACT FROM AUTHOR]

Depression is associated with thrombotic risk and arterial events, its proper management is strongly recommended in coronary artery disease (CAD) patients. We have previously shown that the Brain-Derived Neurotrophic Factor (BDNF)Val66Met polymorphism, related to depression, is associated with arterial thrombosis in mice, and with an increased risk of acute myocardial infarction in humans. Herein, expanding the previous findings on BDNFVal66Met polymorphism, we show that desipramine, a norepinephrine reuptake-inhibitor, rescues behavioral impairments, reduces the arterial thrombosis risk, abolishes pathological coagulation and platelet hyper-reactivity, normalizes leukocyte, platelet, and bone marrow megakaryocyte number and restores physiological norepinephrine levels in homozygous knock-in BDNF Val66Met (BDNF Met/Met ) mice. The in vitro data confirm the enhanced procoagulant activity and the alpha 2A -adrenergic receptor (α 2A -ADR) overexpression found in BDNF Met/Met mice and we provide evidence that, in presence of Met variant, norepinephrine is crucial to up-regulate procoagulant activity and to enhance platelet generation. The α 2 -ADR antagonist rauwolscine rescues the prothrombotic phenotype in BDNF Met/Met mice and reduces procoagulant activity and platelet generation in cells transfected with BDNF Met plasmid or exposed to pro-BDNF Met peptide. Finally, we show that homozygous BDNF Met/Met CAD patients have hyper-reactive platelets overexpressing abundant α 2A -ADR. The great proplatelet release from their megakaryocytes well reflects their higher circulating platelet number compared to BDNF Val/Val patients. These data reveal an unprecedented described role of Met allele in the dysregulation of norepinephrine/α 2A -ADR pathway that may explain the predisposition to arterial thrombosis. Overall, the development of α 2A -ADR inhibitors might represent a pharmacological treatment for depression-associated thrombotic conditions in this specific subgroup of CAD patients., (Copyright © 2021 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Brain-Derived Neurotrophic Factor (BDNF) Val66Met polymorphism has been associated with increased susceptibility to develop mood disorders and recently it has been also linked with cardiovascular disease (CVD). Interestingly, stressful conditions unveil the anxious/depressive-like behavioral phenotype in heterozygous BDNFVal66Met (BDNF Val/Met ) mice, suggesting an important relationship in terms of gene-environment interaction (GxE). However, the interplay between stress and BDNF Val/Met in relation to CVD is completely unknown. Here, we showed that BDNF Val/Met mice display a greater propensity to arterial thrombosis than wild type BDNF Val/Val mice after 7 days of restraint stress (RS). RS markedly increased the number of leukocytes and platelets, and induced hyper-responsive platelets as showed by increased circulating platelet/leukocyte aggregates and enhanced expression of P-selectin and GPIIbIIIa in heterozygous mutant mice. In addition, stressed BDNF Val/Met mice had a greater number of large and reticulated platelets but comparable number and maturation profile of bone marrow megakaryocytes compared to BDNF Val/Val mice. Interestingly, RS led to a significant reduction of BDNF expression accompanied by an increased activity of tissue factor in the aorta of both BDNF Val/Val and BDNF Val/Met mice. In conclusion, we provide evidence that sub-chronic stress unveils prothrombotic phenotype in heterozygous BDNF Val66Met mice affecting both the number and functionality of blood circulating cells, and the expression of key thrombotic molecules in aorta. Human studies will be crucial to understand whether this GxE interaction need to be taken into account in risk stratification of coronary artery disease (CAD) patients.