Vascular modulation through exercise improves chemotherapy efficacy in Ewing sarcoma.

Recent studies in mouse models of cancer have shown that exercise improves tumor vascular function, thereby improving chemotherapy delivery and efficacy. However, the mechanisms underlying this improvement remain unclear and the effect of exercise on Ewing sarcoma (ES), a pediatric bone and soft tissue cancer, is unknown. The effect of exercise on tumor vascular hyperpermeability, which inversely correlates with drug delivery to the tumor, has also not been evaluated. We hypothesized that exercise improves chemotherapy efficacy by enhancing its delivery through improving tumor vascular permeability. We treated ES-bearing mice with doxorubicin with or without moderate treadmill exercise. Exercise did not significantly alter ES tumor vessel morphology. However, compared to control mice, tumors of exercised mice had significantly reduced hyperpermeability, significantly decreased hypoxia, and higher doxorubicin penetration. Compared to doxorubicin alone, doxorubicin plus exercise inhibited tumor growth more efficiently. We evaluated endothelial cell sphingosine-1-phosphate receptors 1 and 2 (S1PR1 and S1PR2) as potential mediators of the improved vascular permeability and increased function afforded by exercise. Relative to tumors from control mice, vessels in tumors from exercised mice had increased S1PR1 and decreased S1PR2 expression. Our results support a model in which exercise remodels ES vasculature to reduce vessel hyperpermeability, potentially via modulation of S1PR1 and S1PR2, thereby improving doxorubicin delivery and inhibiting tumor growth more than doxorubicin alone does. Our data suggest moderate aerobic exercise should be tested in clinical trials as a potentially useful adjuvant to standard chemotherapy for patients with ES.

MiR-126 on mice with coronary artery disease by targeting S1PR2.

OBJECTIVE: To screen the differentially expressed micro ribonucleic acids (miRNAs) in the serum of coronary atherosclerosis patients, and to investigate their possible mechanisms of action. PATIENTS AND METHODS: The differentially expressed serum miRNAs were screened from 3 coronary artery disease (CAD) patients and 3 healthy controls using miRNA expression profiles, which were verified using low-throughput quantitative Reverse Transcription-Polymerase Chain Reaction (RT-qPCR) assay. 60 apolipoprotein E (ApoE)-/- mice were divided into model group, agomir-126 group, agomir-control (con) group, and antagomir-126 group using a random number table. They were fed with high-fat diets (21% fat and 0.15% cholesterol) ad libitum for 15 weeks to establish the mouse model of CAD. Then, hematoxylin and eosin (HE) staining was applied to detect the impact of miR-126 expression level on the tissue morphology in the thoracic aortic region. The influences of miR-126 expression level on the secretion levels of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1ß), and IL-10 were determined via enzyme-linked immunosorbent assay (ELISA). Western blotting assay was performed to examine the effects of miR-126 expression level on the expression levels of nuclear factor-kappa B (NF-κB) and vascular cell adhesion molecule-1 (VACM-1) in the tissues of the thoracic aortic region of the mice. The correlation between miR-126 expression level and sphingosine-1-phosphate receptor 2 (S1PR2) in the serum of CAD patients and animal models was analyzed by the Pearson correlation coefficient method. The targets of miR-126 were predicted using the bioinformatics method, and the direct targets were verified through investigations. Western blotting assay and ELISA were adopted to detect the impacts of miR-126 expression level on the expression and secretion levels of TNF-α, IL-1ß, and IL-10 in S1P + oxidized low-density lipoprotein (ox-LDL)-induced human umbilical vein endothelial cells (HUVECs). Lentivirus-small hairpin RNA (shRNA) was utilized to knock down the expression level of S1RP2 to determine whether miR-126 affected the increase in the inflammation level in S1P + ox-LDL-induced HUVECs by targeting S1RP2. RESULTS: Compared with those in control group, 4 miRNAs (miR-126, miR-206, miR-4297, and miR-3646) in the serum of CAD patients exhibited the most significant expression differences, which increased by 6.72, 7.11, 13.57, and 21.22 times, respectively. The verification results of low-throughput RT-qPCR assay indicated that there were remarkable changes in the expression levels of the 4 selected miRNAs with differential expressions in comparison with those in control group, displaying statistically significant differences (p<0.01). The results of HE staining manifested that the coronary atherosclerotic plaques were reduced markedly in agomir-126 group, while notably more coronary atherosclerotic plaques were formed in the thoracic aortic region in antagomir-126 group. Meanwhile, the elevated expression level of miR-126 evidently lowered the expressions of serum TNF-α and IL-1ß, but significantly increased the expression of IL-10 in the mouse model of CAD. According to the analysis results of the Pearson correlation coefficient method, the miR-126 expression level was negatively correlated with S1PR2 expression level in the serum of both CAD patients and animal models (r=-0.6123, r=-5.37). It was shown in bioinformatics prediction and luciferase reporter gene assay that miR-126 negatively regulated the S1PR2 expression by targeting the 3' untranslated region (UTR) of S1PR2 messenger RNA (mRNA). In the in vitro inflammation model, the increased expression level of miR-126 could relieve the inflammation in cells induced by S1P + ox-LDL. Based on the results of both Western blotting assay and ELISA, the differences in the expression and secretion levels of TNF-α, IL-1ß, and IL-10, as well as the expression levels of signaling molecules of the NF-κB signaling pathway, in the cells were not statistically significant among miR-126 mimic treatment group, sh-S1PR2 group, and miR-126 mimic + sh-S1PR2 group, indicating that miR-126 affects the inflammation level in HUVECs by targeting S1PR2. CONCLUSIONS: MiR-126 represses the progression of coronary atherosclerosis in the mice by binding to S1PR2. The results of this research may propose a new mechanism of miR-126 in exerting its therapeutic effects and possess potential value for the treatment of CAD in the future.

Sphingosine 1 phosphate receptor-1 (S1P1) promotes tumor-associated regulatory T cell expansion: leading to poor survival in bladder cancer.

Regulatory T cells (Tregs) represent an important contributor to cancer immune escape, but the molecular mechanism responsible for Treg expansion in tumors is heterogeneous and unclear. Here, we investigated the role of S1P1, a receptor of the bioactive lipid sphingosine 1-phosphate (S1P), in regulating the crosstalk between tumor cells and tumor-associated Tregs in bladder cancer (BC). We found that the frequency of CD4+Foxp3+ Tregs was increased in circulating and tumor-infiltrating lymphocytes from BC patients. S1P1 expression was upregulated in BC tissues compared with tumor-adjacent tissues and was positively correlated with the density of tumor-infiltrated Foxp3+ Tregs. Both S1P1 and Treg predicted poor overall survival in BC patients. The in vitro data paralleled the in vivo data and suggested that the activation or overexpression of S1P1 in BC cells promoted the generation of BC-induced (i)Tregs from CD4+CD25-cells, and the generation of these cells was reversed by treatment with anti-IL-10 or anti-TGF-ß. Moreover, S1P1 promoted Treg migration mediated by BC cells. Mechanistically, S1P1 activated the TGF-ß signaling pathway, leading to the secretion of TGF-ß and IL-10 from BC cells. In total, our findings suggest that S1P1 induces tumor-derived Treg expansion in a cell-specific manner and serves as a potent prognostic biomarker and therapeutic target in BC.