RESUMO
BACKGROUND: Vasculogenic mimicry (VM) is a potential cause of resistance to antiangiogenic therapy and is closely related to the malignant progression of tumors. It has been shown that noncoding RNAs play an important role in the formation of VM in malignant tumors. However, the role of circRNAs in VM of bladder cancer and the regulatory mechanisms are unclear. METHODS: Firstly, hsa_circ_0000520 was identified to have circular character by Sanger sequencing and Rnase R assays. Secondly, the potential clinical value of hsa_circ_0000520 was explored by quantitative real-time polymerase chain reaction (qRT-PCR) and fluorescence in situ hybridization (FISH) of clinical specimens. Thirdly, the role of hsa_circ_0000520 in bladder cancer invasion, migration, and VM formation was examined by in vivo and in vitro experiments. Finally, the regulatory mechanisms of hsa_circ_0000520 in the malignant progression of bladder cancer were elucidated by RNA binding protein immunoprecipitation (RIP), RNA pulldown, co-immunoprecipitation (co-IP), qRT-PCR, Western blot (WB), and fluorescence co-localization. RESULTS: Hsa_circ_0000520 was characterized as a circular RNA and was lowly expressed in bladder cancer compared with the paracancer. Bladder cancer patients with high expression of hsa_circ_0000520 had better survival prognosis. Functionally, hsa_circ_0000520 inhibited bladder cancer invasion, migration, and VM formation. Mechanistically, hsa_circ_0000520 acted as a scaffold to promote binding of UBE2V1/UBC13 to Lin28a, further promoting the ubiquitous degradation of Lin28a, improving PTEN mRNA stability, and inhibiting the phosphorylation of the PI3K/AKT pathway. The formation of hsa_circ_0000520 in bladder cancer was regulated by RNA binding protein QKI. CONCLUSIONS: Hsa_circ_0000520 inhibits metastasis and VM formation in bladder cancer and is a potential target for bladder cancer diagnosis and treatment.
Assuntos
Movimento Celular , PTEN Fosfo-Hidrolase , Fosfatidilinositol 3-Quinases , RNA Circular , Proteínas de Ligação a RNA , Transdução de Sinais , Neoplasias da Bexiga Urinária , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/metabolismo , Humanos , RNA Circular/genética , RNA Circular/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Transdução de Sinais/genética , PTEN Fosfo-Hidrolase/metabolismo , PTEN Fosfo-Hidrolase/genética , Linhagem Celular Tumoral , Fosfatidilinositol 3-Quinases/metabolismo , Fosfatidilinositol 3-Quinases/genética , Movimento Celular/genética , Masculino , Animais , Regulação Neoplásica da Expressão Gênica , Metástase Neoplásica , Feminino , Neovascularização Patológica/genética , Camundongos Nus , Camundongos , Pessoa de Meia-Idade , Camundongos Endogâmicos BALB CRESUMO
Ribonuclease (RNase) reportedly exerts organ-protective effects in several pathological conditions, including ischemia reperfusion (I/R), but whether it can exhibit protective effect on intestinal I/R injury and potential mechanisms remain unknown. The present study was aimed to evaluate the effects of RNase on intestinal I/R injury and explore the underlying mechanisms. Thirty-two wild-type C57BL/6J adult male mice were evenly divided into a sham group, a sham + RNase group, an I/R group and an I/R + RNase group. Intestinal I/R was produced by clamping the superior mesenteric artery for 1 h followed by reperfusion for 2 h. All mice were treated with 3 doses of RNase or the same dosage of normal saline at different points. It was found that intestinal I/R caused significant intestinal injury and an increase in levels of extracellular RNAs (exRNAs). Treatment with RNase significantly reduced the inflammatory cytokine production, inhibited intestinal apoptosis and down-regulated the expression of toll like receptor 3 in intestinal tissues. In conclusion, increased exRNAs may contribute to intestinal I/R injury in adult mice, and RNase treatment during perioperative window is effective for attenuating intestinal I/R injury.