Aim: The aim of this study was to investigate the effect of microRNA-1224-5p (miR-1224-5p) on tumor endothelial cells (TECs) of human hepatocellular carcinoma (HCC).
Subjects and methods: Oligonucleotides were chemically synthesized and transfected into TECs using Lipofectamine 2000. TECs were divided into three groups, namely a control (CON) group without transfection, a negative control (NC) group transfected with negative control oligonucleotides and green fluorescent protein (GFP), and a micro-up (MU) group transfected with miR-1224-5p mimic and GFP. The expression of miR-1224-5p was quantified via quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The proliferation of TECs was detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the optical density value at 490 nm was measured after every 24 h. Apoptosis was detected via flow cytometry using a 7-aminoactinomycin/APC Annexin V kit. The migration and invasion of TECs were detected using transwell assay. The tube formation ability was evaluated using the tube formation assay.
Results: Oligonucleotides were successfully transduced into TECs, and the expression of miR-1224-5p was specifically upregulated. The results of qRT-PCR analysis showed that the expression of miR-1224-5p was significantly upregulated in the MU group (2-ΔΔCt = 3.27 ± 0.15) than in the CON group (2-ΔΔCt = 1) and NC group (2-ΔΔCt = 1.08 ± 0.11) (P < 0.01). The results of MTT assay showed that the cell proliferation was significantly inhibited in the MU group at four time points than in the CON and NC groups (P < 0.01). Flow cytometry analysis revealed the significant increase in apoptosis of cells from the MU group (19.29% ± 0.95%) than those from the CON (8.73% ± 0.64%) and NC (9.51% ± 0.56%) (P < 0.01) groups. The migration ability was significantly inhibited in MU group (51.0 ± 3.6) as compared with CON (77.7 ± 2.5) and NC (79.2 ± 3.5) groups (P < 0.01). The invasion ability of TECs was significantly inhibited in MU group (9.8 ± 1.3) than in CON (15.8 ± 0.8) and NC (15.4 ± 0.9) groups (P < 0.01). The ability of tube formation of TECs was completely inhibited in MU group but remained unaffected in CON and NC groups.
Conclusions: miR-1224-5p may serve as a potential tumor suppressor in HCC. Upregulation in miR-1224-5p expression may decrease proliferation, induce apoptosis, inhibit migration and invasion, and suppress tube formation in TECs of human HCC.
Keywords: Hepatocellular carcinoma; microRNA-1224-5p; tumor endothelial cell.