RESUMO
PURPOSE: The present study aimed to identify differentially expressed circRNAs in thyroid cancer and verify their potential functions. METHODS: Next-generation sequencing was used to identify differentially expressed circRNAs between papillary thyroid carcinoma (PTC) tissues and paired pericarcinomatous tissues. Polymerase chain reaction and Sanger sequencing methods successfully identified hsa_circ_0007694. A hsa_circ_0007694 over-expression vector was prepared to determine the effect of this circRNA on proliferation, migration, invasion, apoptosis, and the cell cycle in PTC cells. An in vivo animal assay was conducted by injecting PTC cells into the chests of mice. Further, RNA-seq was performed, followed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, to verify the regulatory mechanism of hsa_circ_0007694. Western blotting was used to verify the genes thought to be involved in the hsa_circ_0007694 regulatory pathways based on KEGG analysis. RESULTS: We identified a circRNA, hsa_circ_0007694 that was down-regulated in PTC tissues compared to pericarcinomatous tissues. Over-expression of hsa_circ_0007694 promoted apoptosis and inhibited proliferation, migration, and invasion in PTC cells in vitro, and decreased tumor growth in vivo. Transcriptome sequence analysis suggested 129 differentially expressed genes between PTC tissue and paired pericarcinomatous tissue. KEGG analysis and western blotting indicated that the PI3K/AKT/mTOR and Wnt signaling networks are most likely to be related to hsa_circ_0007694 in thyroid cancer. CONCLUSION: The circRNA hsa_circ_0007694 is down-regulated in PTC and is therefore a potential therapeutic target.
RESUMO
BACKGROUND: Recruitment and entrapment of bone marrow-derived endothelial progenitor cells (EPCs) is important in vascular endothelial growth factor (VEGF)-induced angiogenesis. EPC mobilization and differentiation are modulated by stromal-derived factor-1alpha (SDF-1alpha/CXCL12), another important chemokine. In this study, we investigated the hypothesis that SDF-1alpha and VEGF might act synergistically on EPC-mediated vasculogenesis. METHODS: EPCs were isolated and cultured from human peripheral blood, then transduced with retroviral vectors pBabe containing human VEGF(165) complimentary DNA (Td/V-EPCs) and pBabe wild-type (Td/p-EPCs). EPC migration activity was investigated with a modified Boyden chamber assay. EPC apoptosis induced by serum starvation was studied by annexin V assays. The combined effect of local administration of SDF-1alpha and Td/V-EPC transplantation on neovascularization was investigated in a murine model of hind limb ischemia. RESULTS: Over-expression of hVEGF(165) increased SDF-1alpha-mediated EPC migration. SDF-1alpha-mediated migration was significantly increased when EPCs were modified with VEGF (Td/V-EPCs) vs when VEGF was not present (Td/p-EPCs) or when VEGF alone was present (Td/V-EPCs; 196.8 +/- 15.2, 81.2 +/- 9.8, and 67.4 +/- 7.4/mm(2), respectively P < .001). SDF-1alpha combined with VEGF reduced serum starvation-induced apoptosis of EPCs more than SDF-1alpha or VEGF alone (P < .001). To determine the effect of this combination in vivo, SDF-1alpha was locally injected alone into the ischemic hind limb muscle of nude mice or combined with systemically injected Td/V-EPCs. The SDF-1alpha plus VEGF group showed significantly increased local accumulation of EPCs, blood-flow recovery, and capillary density compared with the other groups. The ratio of ischemic/normal blood flow in Td/V-EPCs plus SDF-1alpha group was significantly higher (P < .01), as was capillary density (capillaries/mm(2)), an index of neovascularization (Td/V-EPCs plus SDF-1alpha group, 863 +/- 31; no treatment, 395 +/-13; SDF-1alpha, 520 +/- 29; Td/p-EPCs, 448 +/- 28; Td/p-EPCs plus SDF-1alpha, 620 +/- 29; Td/V-EPCs, 570 +/- 30; P < .01). To investigate a possible mechanistic basis, we showed that VEGF up-regulated the receptor for SDF-1alpha, CXCR4, on EPCs in vitro. CONCLUSION: The combination of SDF-1alpha and VEGF greatly increases EPC-mediated angiogenesis. The use VEGF and SDF-1alpha together, rather than alone, will be a novel and efficient angiogenesis strategy to provide therapeutic neovascularization.
