Combination of Genomic Landsscape and 3D Culture Functional Assays Bridges Sarcoma Phenotype to Target and Immunotherapy.

Genomic-based precision medicine has not only improved tumour therapy but has also shown its weaknesses. Genomic profiling and mutation analysis have identified alterations that play a major role in sarcoma pathogenesis and evolution. However, they have not been sufficient in predicting tumour vulnerability and advancing treatment. The relative rarity of sarcomas and the genetic heterogeneity between subtypes also stand in the way of gaining statistically significant results from clinical trials. Personalized three-dimensional tumour models that reflect the specific histologic subtype are emerging as functional assays to test anticancer drugs, complementing genomic screening. Here, we provide an overview of current target therapy for sarcomas and discuss functional assays based on 3D models that, by recapitulating the molecular pathways and tumour microenvironment, may predict patient response to treatments. This approach opens new avenues to improve precision medicine when genomic and pathway alterations are not sufficient to guide the choice of the most promising treatment. Furthermore, we discuss the aspects of the 3D culture assays that need to be improved, such as the standardisation of growth conditions and the definition of in vitro responses that can be used as a cut-off for clinical implementation.

Therapeutic targeting of P2X4 receptor and mitochondrial metabolism in clear cell renal carcinoma models.

BACKGROUND: Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cancer. Large-scale metabolomic data have associated metabolic alterations with the pathogenesis and progression of renal carcinoma and have correlated mitochondrial activity with poor survival in a subset of patients. The aim of this study was to determine whether targeting mitochondria-lysosome interaction could be a novel therapeutic approach using patient-derived organoids as avatar for drug response. METHODS: RNAseq data analysis and immunohistochemistry were used to show overexpression of Purinergic receptor 4 (P2XR4) in clear cell carcinomas. Seahorse experiments, immunofluorescence and fluorescence cell sorting were used to demonstrate that P2XR4 regulates mitochondrial activity and the balance of radical oxygen species. Pharmacological inhibitors and genetic silencing promoted lysosomal damage, calcium overload in mitochondria and cell death via both necrosis and apoptosis. Finally, we established patient-derived organoids and murine xenograft models to investigate the antitumor effect of P2XR4 inhibition using imaging drug screening, viability assay and immunohistochemistry. RESULTS: Our data suggest that oxo-phosphorylation is the main source of tumor-derived ATP in a subset of ccRCC cells expressing P2XR4, which exerts a critical impact on tumor energy metabolism and mitochondrial activity. Prolonged mitochondrial failure induced by pharmacological inhibition or P2XR4 silencing was associated with increased oxygen radical species, changes in mitochondrial permeability (i.e., opening of the transition pore complex, dissipation of membrane potential, and calcium overload). Interestingly, higher mitochondrial activity in patient derived organoids was associated with greater sensitivity to P2XR4 inhibition and tumor reduction in a xenograft model. CONCLUSION: Overall, our results suggest that the perturbed balance between lysosomal integrity and mitochondrial activity induced by P2XR4 inhibition may represent a new therapeutic strategy for a subset of patients with renal carcinoma and that individualized organoids may be help to predict drug efficacy.

Glycoxydation promotes vascular damage via MAPK-ERK/JNK pathways.

Oxidation and glycation enhance foam cell formation via MAPK/JNK in euglycemic and diabetic subjects. Here, we investigated the effects of glycated and oxidized LDL (glc-oxLDL) on MAPK-ERK and JNK signaling pathways using human coronary smooth muscle cells. Glc-oxLDL induced a broad cascade of MAPK/JNK-dependent signaling transduction pathways and the AP-1 complex. In glc-oxLDL treated coronary arterioles, tumor necrosis factor (TNF) α increased JNK phosphorylation, whereas protein kinase inhibitor dimethylaminopurine (DMAP) prevented the TNF-induced increase in JNK phosphorylation. The role of MKK4 and JNK were then investigated in vivo, using apolipoprotein E knockout (ApoE(-/-)) mice. Peritoneal macrophages, isolated from spontaneously hyperlipidemic but euglycemic mice showed increases in both proteins and phosphorylated proteins. Compared to streptozotocin-treated diabetic C57BL6 and nondiabetic C57BL6 Wt mice, in streptozotocin-diabetic ApoE(-/-) mice, the increment of foam cell formation corresponded to an increment of phosphorylation of JNK1, JNK2, and MMK4. Thus, we provide a first line of evidence that MAPK-ERK/JNK pathways are involved in vascular damage induced by glycoxidation.

Maternal hypercholesterolaemia during pregnancy affects severity of myocardial infarction in young adults.

AIMS: Elevated maternal cholesterol during pregnancy (MCP) enhances atherogenesis in childhood, but its possible impact on acute myocardial infarction (AMI) in adults is unknown. METHODS AND RESULTS: We retrospectively evaluated 310 patients who were admitted to hospital and whose MCP data were retrievable. Eighty-nine AMI patients with typical chest pain, transmural infarction Q-waves, elevated creatinine kinase, and 221 controls hospitalized for other reasons were identified. The AMI cohort was classified by MI severity (severe = involving three arteries, left ventricle ejection fraction ≤35, CK-peak >1200 mg/dL, or CK-MB >200 mg/dL). The association of MCP with AMI severity was tested by linear and multiple regression analysis that included conventional cardiovascular risk factors, gender, age, and treatment. Associations of MCP with body mass index (BMI) in patients were assessed by linear correlation. In the AMI cohort, MCP correlated with four measures of AMI severity: number of vessels (ß = 0.382, P = 0.001), ejection fraction (ß = -0.315, P = 0.003), CK (ß = 0.260, P = 0.014), and CK-MB (ß = 0.334, P = 0.001), as well as survival time (ß = -0.252, P = 0.031). In multivariate analysis of patients stratified by AMI severity, MCP predicted AMI severity independently of age, gender, BMI, and CHD risk factors (odds ratio = 1.382, 95% confidence interval 1.046-1.825; P = 0.023). Survival was affected mainly by AMI severity. CONCLUSIONS: Maternal cholesterol during pregnancy is associated with adult BMI, atherosclerosis-related risk, and severity of AMI.

Effect of gestational hypercholesterolemia and maternal immunization on offspring plasma eicosanoids.

OBJECTIVE: Maternal immunization with oxidized low-density lipoprotein prior to pregnancy prevents pathogenic in utero programming by gestational hypercholesterolemia, but it is unknown whether gestational hypercholesterolemia and maternal immunization affect similar pathways. STUDY DESIGN: A lipidomic approach was used for unbiased plasma eicosanoid profiling in adult offspring of immunized and nonimmunized normocholesterolemic or hypercholesterolemic rabbit mothers. RESULTS: Gestational hypercholesterolemia was associated with increased levels of some eicosanoids formed by the cyclooxygenase and 12-lipoxygenase pathways only (including thromboxane B2, prostaglandin [PG] F2α, PGE2, and PGD2). Immunization of hypercholesterolemic or normocholesterolemic mothers reduced 9 of 14 eicosanoids of the cyclooxygenase pathway, 21 of 23 eicosanoids of the 5- and 12-lipoxygenase pathways (eg, 5-hydroxyeicosatetraenoic acid, hepoxilin B3, 12-hydroxyeicosatetraenoic acid), 8 of 19 eicosanoids of the cytochrome P-450 pathway, and all metabolites of the nonenzymatic pathway. CONCLUSION: Maternal immunization not only counteracts in utero programming by gestational hypercholesterolemia but reduces a broad range of eicosanoid modulators of immunity and inflammation in offspring.

Pneumococcal vaccination decreases atherosclerotic lesion formation: molecular mimicry between Streptococcus pneumoniae and oxidized LDL.

During the progression of atherosclerosis, autoantibodies are induced to epitopes of oxidized low-density lipoprotein (oxLDL) and active immunization of hypercholesterolemic mice with oxLDL ameliorates atherogenesis. We unexpectedly found that many autoantibodies to oxLDL derived from 'naive' atherosclerotic mice share complete genetic and structural identity with antibodies from the classic anti-phosphorylcholine B-cell clone, T15, which protect against common infectious pathogens, including pneumococci. To investigate whether in vivo exposure to pneumococci can affect atherogenesis, we immunized Ldlr(-/-) mice with Streptococcus pneumoniae. This induced high circulating levels of oxLDL-specific IgM and a persistent expansion of oxLDL-specific T15 IgM-secreting B cells primarily in the spleen, which were cross-reactive with pneumococcal determinants. Pneumococcal immunization decreased the extent of atherosclerosis, and plasma from these mice had an enhanced capacity to block the binding of oxLDL to macrophages. These studies show molecular mimicry between epitopes of oxLDL and S. pneumoniae and indicate that these immune responses can have beneficial effects.

Lysosome purinergic receptor P2X4 regulates neoangiogenesis induced by microvesicles from sarcoma patients.

The tumor microenvironment modulates cancer growth. Extracellular vesicles (EVs) have been identified as key mediators of intercellular communication, but their role in tumor growth is largely unexplored. Here, we demonstrate that EVs from sarcoma patients promote neoangiogenesis via a purinergic X receptor 4 (P2XR4) -dependent mechanism in vitro and in vivo. Using a proteomic approach, we analyzed the protein content of plasma EVs and identified critical activated pathways in human umbilical vein endothelial cells (HUVECs) and human progenitor hematopoietic cells (CD34+). We then showed that vessel formation was due to rapid mitochondrial activation, intracellular Ca2+ mobilization, increased extracellular ATP, and trafficking of the lysosomal P2XR4 to the cell membrane, which is required for cell motility and formation of stable branching vascular networks. Cell membrane translocation of P2XR4 was induced by proteins and chemokines contained in EVs (e.g. Del-1 and SDF-1). Del-1 was found expressed in many EVs from sarcoma tumors and several tumor types. P2XR4 blockade reduced EVs-induced vessels in angioreactors, as well as intratumor vascularization in mouse xenografts. Together, these findings identify P2XR4 as a key mediator of EVs-induced tumor angiogenesis via a signaling mediated by mitochondria-lysosome-sensing response in endothelial cells, and indicate a novel target for therapeutic interventions.

Maternal C-reactive protein and developmental programming of atherosclerosis.

OBJECTIVE: Maternal hypercholesterolemia during pregnancy enhances the susceptibility to atherosclerosis in their offspring by oxidation-dependent mechanisms. The present study investigated whether maternal C-reactive protein (CRP) level, which is an indicator of inflammation and cardiovascular risk, or smoking, which enhances oxidative stress, predict the in utero programming of atherosclerosis. STUDY DESIGN: Subsets of patients from the Fate of Early Lesions in Childhood study (156 normocholesterolemic children) were examined at autopsy, classified by maternal cholesterol levels during pregnancy. Maternal CRP level was correlated with maternal cholesterol and aortic atherosclerosis of children. RESULTS: CRP level was elevated in hypercholesterolemic mothers and showed significant correlation with atherogenesis in children in univariate and multivariate analysis. However, many hypercholesterolemic mothers did not have elevated CRP levels. Smoking only correlated in univariate analysis. CONCLUSION: CRP level during pregnancy is a predictor of increased atherogenesis in children of hypercholesterolemic mothers, albeit a weaker one than maternal cholesterol. In the presence of hypercholesterolemia, maternal smoking does not further enhance atherogenic programming.

Maternal immunization programs postnatal immune responses and reduces atherosclerosis in offspring.

Maternal hypercholesterolemia during pregnancy increases offspring susceptibility to atherosclerosis by an oxidation-dependent mechanism. The present studies investigated whether maternal immunization with oxidized LDL (OxLDL) before pregnancy protects the fetus from atherogenic in utero programming by maternal hypercholesterolemia. Maternal immunization of NZW rabbits and LDL receptor-deficient mice indeed reduced atherosclerosis in adult offspring by up to 56%, but the protective effect could not be attributed to a reduction of fetal exposure to hypercholesterolemia alone, and even nonspecific immune stimulation with adjuvant only provided some protection. Unexpectedly, offspring of immunized mothers developed increased IgM antibodies to selective OxLDL epitopes and increased IgM-LDL immune complexes, compared with offspring of nonimmunized controls. Even naïve offspring of OxLDL-immunized mothers never exposed to postnatal hypercholesterolemia responded to a one-time OxLDL and KLH challenge with greater OxLDL-specific IgM responses, increased OxLDL-specific IgM-secreting B cells, and more IgM-LDL immune complexes. In contrast, maternal immunization with KLH, a T cell-dependent nonmammalian antigen, did not influence postnatal immune responses. Effects of maternal OxLDL-immunization on offspring B cells and selective antibodies were independent of transplacental passage of maternal immunoglobulins. Results show that maternal immunization with antigens prevalent in atherosclerotic lesions reduces atherogenesis in their offspring by mechanisms that include, but are not limited to, reduced fetal exposure to maternal hypercholesterolemia and lipid peroxidation. More importantly, they demonstrate in principle that maternal adaptive immunity to selective antigens influences postnatal B cell and antibody responses in offspring, and that modulation of in utero immune programming may influence immune-modulated diseases later in life.

A diet-induced hypercholesterolemic murine model to study atherogenesis without obesity and metabolic syndrome.

OBJECTIVE: Western-type high-fat/high-cholesterol diets used to induce atherogenesis in low-density lipoprotein (LDL) receptor-deficient mice also lead to obesity with concomitant metabolic complications, eg, hypertriglyceridemia, hyperinsulinemia, and insulin resistance. Our aim was to design a diet inducing atherosclerosis through moderate hypercholesterolemia without associated parameters of the metabolic syndrome. METHODS AND RESULTS: Male LDL receptor-deficient mice were fed regular chow (RC; 0.01% cholesterol/4.4% fat), cholesterol-enriched regular chow (HC; 1% cholesterol/4.4% fat), or Western diet (WD 0.06% cholesterol/21% milk fat) for 28 weeks. HC-feeding led to elevated plasma (approximately 20.7 mmol/L [800 mg/dL]) and LDL cholesterol and accelerated atherosclerosis. Plasma triglycerides were unaffected. Compared with RC-fed controls, HC-fed mice had normal body weight gain and normal fasting levels of glucose, free fatty acids, and insulin. In contrast, WD-fed mice were extremely hypercholesterolemic (>41.4 mmol/L), obese, hypertriglyceridemic, hyperinsulinemic, insulin resistant, and showed adverse health such as skin/fur abnormalities and hepatic steatosis. Although atherosclerotic surface areas in the entire aorta were similar in HC-fed and WD-fed mice, lesions in aortic origin cross sections were significantly larger in WD-fed mice. However, morphology was similar in lesions of equal size. CONCLUSIONS: The HC diet induced moderate hypercholesterolemia and extensive atherosclerosis and should be useful to study specific aspects of atherogenesis in the absence of confounding effects of the metabolic syndrome.

IL-5 links adaptive and natural immunity specific for epitopes of oxidized LDL and protects from atherosclerosis.

During atherogenesis, LDL is oxidized, generating various oxidation-specific neoepitopes, such as malondialdehyde-modified (MDA-modified) LDL (MDA-LDL) or the phosphorylcholine (PC) headgroup of oxidized phospholipids (OxPLs). These epitopes are recognized by both adaptive T cell-dependent (TD) and innate T cell-independent type 2 (TI-2) immune responses. We previously showed that immunization of mice with MDA-LDL induces a TD response and atheroprotection. In addition, a PC-based immunization strategy that leads to a TI-2 expansion of innate B-1 cells and secretion of T15/EO6 clonotype natural IgM antibodies, which bind the PC of OxPLs within oxidized LDL (OxLDL), also reduces atherogenesis. T15/EO6 antibodies inhibit OxLDL uptake by macrophages. We now report that immunization with MDA-LDL, which does not contain OxPL, unexpectedly led to the expansion of T15/EO6 antibodies. MDA-LDL immunization caused a preferential expansion of MDA-LDL-specific Th2 cells that prominently secreted IL-5. In turn, IL-5 provided noncognate stimulation to innate B-1 cells, leading to increased secretion of T15/EO6 IgM. Using a bone marrow transplant model, we also demonstrated that IL-5 deficiency led to decreased titers of T15/EO6 and accelerated atherosclerosis. Thus, IL-5 links adaptive and natural immunity specific to epitopes of OxLDL and protects from atherosclerosis, in part by stimulating the expansion of atheroprotective natural IgM specific for OxLDL.

Differential inhibition of macrophage foam-cell formation and atherosclerosis in mice by PPARalpha, beta/delta, and gamma.

PPARalpha, beta/delta, and gamma regulate genes involved in the control of lipid metabolism and inflammation and are expressed in all major cell types of atherosclerotic lesions. In vitro studies have suggested that PPARs exert antiatherogenic effects by inhibiting the expression of proinflammatory genes and enhancing cholesterol efflux via activation of the liver X receptor-ABCA1 (LXR-ABCA1) pathway. To investigate the potential importance of these activities in vivo, we performed a systematic analysis of the effects of PPARalpha, beta, and gamma agonists on foam-cell formation and atherosclerosis in male LDL receptor-deficient (LDLR(-/-)) mice. Like the PPARgamma agonist, a PPARalpha-specific agonist strongly inhibited atherosclerosis, whereas a PPARbeta-specific agonist failed to inhibit lesion formation. In concert with their effects on atherosclerosis, PPARalpha and PPARgamma agonists, but not the PPARbeta agonist, inhibited the formation of macrophage foam cells in the peritoneal cavity. Unexpectedly, PPARalpha and PPARgamma agonists inhibited foam-cell formation in vivo through distinct ABCA1-independent pathways. While inhibition of foam-cell formation by PPARalpha required LXRs, activation of PPARgamma reduced cholesterol esterification, induced expression of ABCG1, and stimulated HDL-dependent cholesterol efflux in an LXR-independent manner. In concert, these findings reveal receptor-specific mechanisms by which PPARs influence macrophage cholesterol homeostasis. In the future, these mechanisms may be exploited pharmacologically to inhibit the development of atherosclerosis.

Developmental programming: maternal hypercholesterolemia and immunity influence susceptibility to atherosclerosis.

It is increasingly recognized that the in utero environment is an important determinant of adult disease, and extensive epidemiological evidence links dysmetabolic conditions during pregnancy with increased hypertension, cardiovascular disease, and diabetes later in life. The original Barker Hypothesis focused on low birth weight as the primary indicator of postnatal risk, but low birth weight may arise from other, non-metabolic conditions. This has impeded the identification of developmental programming mechanisms. More recently, the focus has shifted to the impact of specific maternal risk factors, such as obesity, metabolic syndrome, and diabetes, on cardiovascular risk in offspring. Inflammation plays a central role in these maternal conditions as well as in offspring atherogenesis, and two key factors that influence inflammation, maternal hypercholesterolemia and maternal immune mechanisms, have been shown to affect the developmental programming of atherosclerosis. Maternal hypercholesterolemia in pregnancy, even if only temporary, is associated with increased fatty streak formation in human fetal arteries and accelerated progression of atherosclerosis in normocholesterolemic children. Conversely, immunization of experimental animals with oxidized low-density lipoprotein cholesterol, an antigen prevalent in atherosclerotic lesions, inhibits the progression of atherosclerosis in the offspring of hypercholesterolemic mothers. These findings indicate it is possible, in principle, to program postnatal immune responses and to reduce atherosclerosis, and potentially other immunomodulated diseases, by targeted maternal immunomodulation.

Minimally oxidized LDL offsets the apoptotic effects of extensively oxidized LDL and free cholesterol in macrophages.

OBJECTIVE: Lipid-loaded macrophage-derived foam cells populate atherosclerotic lesions and produce many pro-inflammatory and plaque-destabilizing factors. An excessive accumulation of extensively oxidized low-density lipoprotein (OxLDL) or free cholesterol (FC), both of which are believed to be major lipid components of macrophages in advanced lesions, rapidly induces apoptosis in macrophages. Indeed, there is evidence of macrophage death in lesions, but how the surviving macrophages avoid death induced by OxLDL, FC, and other factors is not known. METHODS AND RESULTS: Minimally oxidized LDL (mmLDL), which is an early product of progressive LDL oxidation in atherosclerotic lesions, countered OxLDL-induced or FC-induced apoptosis and stimulated macrophage survival both in cell culture and in vivo. DNA fragmentation and caspase-3 activity in OxLDL-treated peritoneal macrophages were significantly reduced by coincubation with mmLDL. In a separate set of experiments, mmLDL significantly reduced annexin V binding to macrophages in which apoptosis was induced by FC loading. In both cellular models, mmLDL activated a pro-survival PI3K/Akt signaling pathway, and PI3K inhibitors, wortmannin and LY294002, eliminated the pro-survival effect of mmLDL. Immunohistochemical examination demonstrated phospho-Akt in murine atherosclerotic lesions. CONCLUSIONS: Minimally oxidized LDL, an early form of oxidized LDL in atherosclerotic lesions, may contribute to prolonged survival of macrophage foam cells in lesions via a PI3K/Akt-dependent mechanism.