赖氨酰氧化酶样蛋白2在胆管癌中的表达以及与血管内皮生长因子A及血管生成的关系

目的:探讨赖氨酰氧化酶样蛋白2(LOXL2)在胆管癌中的表达以及与胆管癌血管生成的关系。方法:下载GEO数据库中相关数据,比较胆管癌组织和癌旁组织LOXL2的mRNA表达差异;通过基因集富集分析法分析LOXL2在胆管癌中的功能;分析各数据集中LOXL2与血管内皮生长因子A(VEGFA)表达的关系。通过Western blot、qRT-PCR和ELISA检测下调或上调胆管癌细胞株中LOXL2的表达后,VEGFA的表达和分泌水平变化。用干扰或过表达LOXL2的胆管癌细胞的条件培养基培养人脐静脉内皮细胞(HUVECs)后,观察其管腔形成情况。结果:GEO数据库分析结果显示,LOXL2在癌组织中的表达明显比癌旁高(P<0.05);LOXL2可能参与了胆管癌血管生成;各GEO数据集中LOXL2与VEGFA的表达均呈正相关(r=0.320、0.243、0.234、0.665,均P<0.05)。在胆管癌细胞中,干扰LOXL2后VEGFA的表达及分泌水平均明显下降,过表达LOXL2后VEGFA的表达和分泌水平均明显升高(均P<0.05)。干扰LOXL2的胆管癌细胞的条件培养基培养后HUVECs管腔形成明显减少,而过表达LOXL2的条件培养基培养后HUVECs管腔形成明显增加(均P<0.05)。结论:LOXL2在胆管癌中的表达升高,并可能通过上调VEGFA的表达促进胆管癌的血管生成。

Expression of lysyl oxidase-like 2 in cholangiocarcinoma and its relations with vascular endothelial growth factor A and angiogenesis

Objective: To investigate the expression of lysyl oxidase-like 2 (LOXL2) in cholangiocarcinoma (CCA) and its association with angiogenesis in CCA.Methods: The relevant data were downloaded from the GEO database, and then, the difference in LOXL2 mRNA expression between CCA tissue and tumor adjacent tissue was compared; the potential function of the LOXL2 in CCA was determined by gene set enrichment analysis; the relationship between the expressions of LOXL2 and vascular endothelial growth factor A (VEGFA) was analyzed in each dataset. The changes in expression and secretion level of VEGFA in CCA cells after down- or up-regulating LOXL2 expression were detected by Western blot, qRT-PCR and ELISA, respectively. The human umbilical vein endothelial cells (HUVECs) were cultured with the conditioned medium from CCA cells with LOXL2 interference or overexpression, and then, the tube formation abilities of the HUVECs were observed. Results: The results of GEO database analyses showed that the LOXL2 expression in CCA tissue was significantly higher than that in tumor adjacent tissue (P<0.05); LOXL2 was possibly associated with angiogenesis in CCA; there was a significant positive correlation between LOXL2 expression and VEGFA expression in each GEO dataset (r=0.320, 0.243, 0.234 and 0.665, all P<0.05). In CCA cells, the VEGFA expression and secretion level of LOXL2 were significantly decreased after LOXL2 interference, and were significantly increased after LOXL2 overexpression (all P<0.05). The number of tube formation was significantly decreased in HUVECs after culture with the conditioned medium from CCA with LOXL2 knockdown, and was significantly increased in HUVECs after culture with the conditioned medium from CCA with LOXL2 overexpression (both P<0.05).Conclusion: LOXL2 expression is increased in CCA and it may promote angiogenesis in CCA through upregulating VEGFA expression.