摘要目的:探讨溶血磷脂酰胆碱酰基转移酶1(LPCAT1)对人脑胶质母细胞瘤(GBM)增殖、侵袭和细胞凋亡的作用及其作用机制。方法:基于中国胶质瘤基因组图谱(CGGA)数据库分析LPCAT1在不同级别[世界卫生组织(WHO)Ⅱ、Ⅲ级和Ⅳ级]胶质瘤中的表达情况。通过蛋白质免疫印迹法(WB)检测LPCAT1在来源于首都医科大学附属北京天坛医院神经外科学中心行手术治疗的低级别胶质瘤(LGG)(WHO Ⅱ级，4例)和GBM(4例)患者组织样本中的表达情况。采用LPCAT1 siRNA转染GBM细胞株LN18，将转染的细胞分为阴性对照组、LPCAT1 si1组和LPCAT1 si2组。采用实时荧光定量PCR(qPCR)和WB检测LPCAT1 siRNA的敲减效率。分别通过CCK-8实验、Transwell实验和流式细胞术明确LPCAT1敲减对各组细胞增殖、侵袭能力和细胞凋亡的影响。采用qPCR和WB检测LPCAT1敲减对表皮生长因子受体(EGFR)的表达及其磷酸化Tyr1068的影响。结果:CGGA数据库分析结果表明，GBM中LPCAT1 mRNA的表达水平显著高于WHO Ⅱ、Ⅲ级胶质瘤(均 P<0.05)。对临床样本的WB结果显示，GBM组织中LPCAT1蛋白的表达显著高于LGG(分别为1.167±0.123和0.561±0.081， t＝4.13， P<0.001)。qPCR和WB结果显示，LPCAT1 si1和LPCAT1 si2组LPCAT1基因和蛋白表达水平均明显低于阴性对照组(均 P<0.01)。CCK-8实验结果显示，LPCAT1 si1和LPCAT1 si2组的吸光度值分别为1.043±0.025、0.875±0.040，均显著低于阴性对照组(1.202±0.028)(均 P<0.01)。Transwell实验结果显示，LPCAT1 si1和LPCAT1 si2组细胞的迁移能力均低于阴性对照组(均 P<0.001)。LPCAT1 si1和LPCAT1 si2组的凋亡细胞比率分别为(49.5±0.3)%和(38.7±0.3)%，均高于阴性对照组[(17.1±0.1)%](均 P<0.001)。qPCR结果显示，LPCAT1 si1和LPCAT1 si2组的EGFR mRNA表达水平均低于阴性对照组(均 P<0.001)。WB结果显示，LPCAT1 si1和LPCAT1 si2组的EGFR Tyr1068磷酸化水平均显著低于阴性对照组(均 P<0.05)。 结论:初步结果表明，通过抑制LPCAT1的表达可降低GBM细胞的增殖和侵袭能力，促进GBM细胞的凋亡。这一作用可能通过减少EGFR磷酸化来介导。

abstractsObjective:To investigate the effect of lysophosphatidylcholine acyltransferase 1 (LPCAT1) on the tumor proliferation, invasion and apoptosis of human glioblastomas (GBMs) and to explore its mechanisms.Methods:Based on the Chinese Glioma Genome Atlas (CGGA) database, the expression of LPCAT1 was analyzed among lower grade gliomas [LGG, World Health Organization(WHO) grade Ⅱ and Ⅲ] and GBMs. The expression of LPCAT1 was validated through Western blot (WB) in 4 LGG and 4 GBM tissue samples from patients undergoing surgical resection at the Neurosurgery Center, Beijing Tiantan Hospital, Capital Medical University. LPCAT1 was knocked down by siRNAs, and the transfected LN18 cells were divided into three experimental groups including negative control group, LPCAT1 si1 group and LPCAT1 si2 group. The knockdown efficiency of LPCAT1 siRNA was detected by real-time quantitative PCR (qPCR) and WB. The effects of LPCAT1 knockdown on tumor cell proliferation, invasion and apoptosis in three experimental groups were detected by cell counting Kit-8(CCK8) test, transwell assay and flow cytometry respectively. The effect of LPCAT1 knockdown on the expression of epidermal growth factor receptor (EGFR) and phosphorylation Tyr1068 of EGFR in the three experimental groups was also detected by qPCR and WB.Results:Based on the CGGA database analysis, LPCAT1 mRNA expression in GBMs was significantly higher than that in WHO grade Ⅱ and Ⅲ gliomas(both P<0.05). WB results based on clinical samples showed that the expression of LPCAT1 in GBM was significantly higher than that in LGG (1.167±0.123 vs. 0.561±0.081, t=4.13, P<0.001). The qPCR results showed that the gene expression level of LPCAT1 in LPCAT1 si1 and LPCAT1 si2 groups were significantly lower than that in negative control group (both P<0.001). WB results revealed the same results (both P<0.01). The results of CCK8 showed that the cell proliferation in LPCAT1 si1 and LPCAT1 si2 groups (absorbance value: 1.043±0.025 and 0.875±0.040 respectively) were significantly lower than that in negative control group (1.202±0.028) (both P<0.01). Transwell experiment showed that the number of migrated cells in LPCAT1 si1 and LPCAT1 si2 groups were significantly lower than that in negative control group (both P<0.001). Flow cytometry showed that the percentage of apoptotic cells in LPCAT1 si1 and LPCAT1 si2 groups (49.5%±0.3% and 38.7%±0.3% respectively) was significantly higher than that in negative control group (17.1%±0.1%) (both P<0.001). The qPCR results showed that the gene expression level of EGFR in LPCAT1 si1 and LPCAT1 si2 groups was significantly lower than that in negative control group (both P<0.001). WB results showed that the EGFR Tyr1068 phosphorylation level in LPCAT1 si1 and LPCAT1 si2 groups was significantly lower than that in negative control group (both P<0.05). Conclusion:Preliminary study has shown that inhibition of LPCAT1 expression can reduce proliferation and invasion of GBM cells, and promote apoptosis of GBM cells, which might be mediated by decreasing the phosphorylation of EGFR.