Effect of miR-513a-5p on etoposide-stimulating B7-H1 expression in retinoblastoma cells

Abstract

This study investigated the effect of etoposide, an anticancer chemotherapy drug, on B7-H1 expression in retinoblastoma (Rb) cells and the role of miR-513a-5p in the process. Rb cells were divided into control and etoposide groups. In the etoposide group, cells were treated with etoposide at different concentrations (2.5, 5, 10, 20 and 40 μg/mL) for 24 h. Those given no treatment of etopside served as controls. Reverse transcription polymerase chain reaction (RT-PCR), fluorescence quantitative PCR and flow cytometry were performed to measure the mRNA and protein expression of B7-H1 in Rb cells. The mRNA expression of miR-513a-5p in Rb cells before and after etoposide treatment was also detected by fluorescence quantitative PCR. The miR-513a-5p mimics and the miR-513a-5p inhibitor were transfected into Rb cells separately, and fluorescence quantitative PCR and flow cytometry were used to detect the effect of the miR-513a-5p mimics or inhibitor on B7-H1 expression. TargetScan5.2 was employed to predict the miR-513a-5p binding sites in the 3'-untranslated region of B7-H1 mRNA. Luciferase reporter plasmids carrying this site were prepared and transfected into Rb cells and luciferase activity analyzed. The results showed that etoposide stimulated the mRNA and protein expression of B7-H1 in Rb cells, which reached a maximal level after treatment with 5 μg/mL etoposide (P<0.05). However, miR-513a-5p expression was decreased in Rb cells after etoposide treatment. When the miR-513a-5p inhibitor was added, B7-H1 expression was increased with the concentration of the miR-513a-5p inhibitor (P<0.05). Moreover, B7-H1 expression was decreased gradually with the concentration of the miR-513a-5p mimics increased (P<0.01). Additionally, the miR-513a-5p mimics were found to inhibit the luciferase activity. It was concluded that etoposide can promote B7-H1 expression in Rb cells, which may be associated with chemoresistance. The promoting effect of etoposide on B7-H1 expression can be reversed by miR-513a-5p mimics. MiR-513a-5p inhibits the mRNA and protein expression of B7-H1 via binding to the 3'-UTR of B7-H1 mRNA.

miR-513a-5p regulates radiosensitivity of osteosarcoma by targeting human apurinic/apyrimidinic endonuclease

“…We screened and further confirmed that seven miRNAs were increased in APE1 knockdown HOS cells, and among them, miR-513a-5p exhibited an approximately 3-fold increase. Although the biological functions and intracellular targets of miR-513a-5p remain to be determined, previous studies suggest that miR-513a-5p is associated with cellular sensitivity to etoposide- and cisplatin-containing chemotherapy in retinoblastoma and non-small cell lung cancer (NSCLC) [ 18 , 19 ]. Additionally, the level of miR-513a-5p in osteosarcoma is reduced based on the data from cell lines and clinical samples.…”

Noncoding RNAs and immune checkpoints—clinical implications as cancer therapeutics

“…During treatment with etoposide, PD-L1 expression levels increase, whereas miR-513-5p expression levels decrease in retinoblastoma cells. Supporting the correlation of expression of PD-L1 and miR-513-5p, PD-L1 expression levels gradually decline with the addition of miR-513-5p mimics to retinoblastoma cells [85].…”

Immunomodulatory MicroRNAs in cancer: targeting immune checkpoints and the tumor microenvironment

“…Additionally, miR-138-5p was found to altered among benzo-a-pyrene-induced miRNA profile changes in lung epithelial cells [23]. Furthermore, the low expression of miR-513 was coupled with PD-L1 overexpression in retinoblastoma [26]. miR-513 is commonly downregulated in patients with chronic biliary inflammation [24].…”

“…Therefore, miR-513 can block the malignant transformation in these cells [25]. Furthermore, the low expression of miR-513 was coupled with PD-L1 overexpression in retinoblastoma [26]. Recent studies showed that miR-513 hinders cell invasion and metastasis in endometrial cancer and that it is implicated in gemcitabine resistance in bladder cancer [27,28].…”