Objective: To explore the expression and clinical significance of circular RNA circHIPK3 in oral squamous cell carcinoma (OSCC), analyze the effect of circHIPK3 on the proliferation of OSCC cells. Methods: The expression of circHIPK3 in OSCC tissues, adjacent non-cancerous tissues and OSCC cell lines were detected by quantitative real-time polymerase chain reaction (qPCR). The correlations between the expression of circHIPK3 in OSCC tissues and the clinicopathological features were analyzed as well. circHIPK3-specific siRNA si-circHIPK3 and negative control siRNA si-NC were designed and synthesised and used to transfect CAL27 and SCC15 cells respectively. The proliferation capacity of CAL27 and SCC15 cells after transfection with si-circHIPK3 was detected by CCK-8 assay. The expression of miR-124 in OSCC was detected by qPCR, and the correlation between expression of circHIPK3 and the expression of miR-124 was analyzed. Using qPCR to detect the expression of miR-124 in CAL27 and SCC15 cells after transfection with si-circHIPK3 and si-NC respectively. Furthermore, using CCK-8 assay to detect the proliferation capacity of CAL27 and SCC15 cells after transfection with si-NC, si-circHIPK3, miR-124 mimic, si-circHIPK3+miR-124 inhibitor. Results: The expression of circHIPK3 in OSCC tissues [2.23 (1.86, 3.00)] was significantly higher than that of the adjacent non-cancerous tissues [1.05 (0.85, 1.26)] (U=1 094, P=0.000). The expression of circHIPK3 in CAL27 (3.02±0.51) and SCC15 cells (3.16±0.75) was higher than those of human normal oral keratinocytes (hNOK) (1.26±0.30) (P=0.000). The expression of circHIPK3 was found to be closely associated with TNM stage (P<0.05) and tumor grades (P<0.05). Knockdown of circHIPK3 can inhibit proliferation of CAL27 and SCC15 cells (P<0.05). The expression of miR-124 in OSCC tissues (0.61±0.35) was significantly lower than that in adjacent non-cancerous tissues (1.13+0.39) (t=-5.36, P<0.05). Correlation analysis showed that the expression of circHIPK3 in OSCC was negatively correlated with the expression of miR-124 (r=-0.767, P<0.001). Moreover, down-regulation of miR-124 rescued the phenotype induced by knockdown of circHIPK3. Conclusions: The expression of circHIPK3 in OSCC was increased, and silencing of circHIPK3 expression can inhibit the proliferation of OSCC cells. Our results suggest that circHIPK3 may play a key role in the occurrence and development process of OSCC through the regulation of miR-124 expression.
目的： 探讨口腔鳞状细胞癌（oral squamous cell carcinoma，OSCC）中环状RNA circHIPK3的表达及临床意义，并探索circHIPK3调控微RNA124表达对OSCC细胞增殖的影响。 方法： 采用实时荧光定量PCR检测90例2016年1月至2017年5月于南昌大学第二附属医院的OSCC患者癌组织、配对的癌旁组织及OSCC细胞株CAL27、SCC15和人正常口腔角质细胞株hNOK中circHIPK3的表达水平并分析其与患者临床病理特征关系。设计合成circHIPK3的靶向小干扰RNA si-circHIPK3和阴性对照序列si-NC，分别转染CAL27和SCC15细胞，细胞计数（cell counting kit-8, CCK-8）检测circHIPK3对CAL27和SCC15细胞增殖能力的影响。实时荧光定量PCR检测微RNA124在OSCC中的表达，分析circHIPK3的表达与微RNA124表达的相关性。CAL27和SCC15细胞分别转染si-circHIPK3和si-NC，实时荧光定量PCR检测细胞中微RNA124表达变化。CAL27和SCC15细胞分别转染si-NC、si-circHIPK3、微RNA124模拟物、si-circHIPK3+微RNA124抑制物，CCK-8法检测OSCC细胞增殖的变化。 结果： OSCC组织中circHIPK3表达水平[2.23（1.86，3.00）]显著高于癌旁正常组织[1.05（0.85，1.26），U=1 094，P=0.000]。CAL27（3.02±0.51，P=0.000）和SCC15细胞（3.16±0.75，P=0.000）中circHIPK3表达水平均显著高于hNOK细胞（1.26±0.30）。circHIPK3在不同临床分期及不同细胞分化程度患者癌组织中表达差异均有统计学意义（P<0.05）。抑制circHIPK3表达后，CAL27和SCC15细胞增殖能力受到明显抑制，差异均有统计学意义（P<0.05）。OSCC组织中微RNA124表达水平（0.61±0.35）较癌旁正常组织显著下调（1.13±0.39，t=-5.36，P<0.05）。相关性分析显示OSCC组织中circHIPK3的表达与微RNA124呈显著负相关（r=-0.767，P<0.001）。与沉默circHIPK3相比，在沉默circHIPK3的CAL27和SCC15细胞中加入微RNA124抑制物共转染之后，沉默circHIPK3抑制细胞增殖的能力部分逆转。 结论： OSCC中circHIPK3的表达水平上调，下调circHIPK3的表达水平可抑制OSCC细胞的增殖，circHIPK3可能通过调控微RNA124表达参与OSCC的发生和发展过程。.
Keywords: Circular RNA; MicroRNAs; Oral sprays.