Effects of exosomal circular RNA-100338 derived from hepatocellular carcinoma on angiogenesis of human umbilical vein endothelial cells

Objective To observe the effects of exosomal circular RNA (circRNA)-100338 derived from hepatocellular carcinoma (HCC) on angiogenesis of human umbilical vein endothelial cells (HUVEC). Methods The exosomes from the supernatant of MHCC97H cells were extracted, purified and identified, and co-incubated with HUVECs (37 ℃, 5% CO2). The exosome tracer experiments traced whether the exosomes could be transformed into HUVECs. MHCC97H cells were transfected with Lipofectamine™ 2000 transfection reagent to extract exosomes from the supernatant of HCC cells after interfering with circRNA-100338 (1 g/L). Proliferation assay was used to detect the changes of proliferation ability of HUVECs [The absorbance (A) values were measured at a wavelength of 450 nm], and angiogenesis assay was applied to evaluate the tubular formation of HUVECs (×100). Results The results of transmission electron microscopy showed that most exosomes from MHCC97H cells were round or oval, and the peak size distribution was 120 nm, which accorded with the characteristics of exosome size. Western blotting was used to detect exosome marker proteins. MHCC97H cells-derived exosomes were internalized by HUVECs. The A values of HUVECs co-cultured with circRNA-100338 interfering group and control group were 0.358±0.005 and 0.436±0.011 (t=-16.227, P<0.01), 0.661±0.052 and 0.888±0.031 (t =-9.146, P<0.01), 1.191±0.084 and 1.542±0.038 (t=-9.296, P<0.01) at 48, 72 and 96 h, respectively. The proliferation ability of HUVECs in interfering group was significantly lower than that in control group after 48-h treatment. In the interferening group, the ability of HUVECs to form tubules was decreased, and the tubular nodules were thin and small. Conclusion HCC-derived exosomal circRNA-100338 enhanced the proliferation ability of HUVECs and promoted endothelial angiogenesis. Key words: Carcinoma, hepatocellular; Exosome; Circular RNA-100338; Proliferation; Angiogenesis