肿瘤细胞系血管内皮生长因子及其受体共表达的研究

背景与目的：血管内皮生长因子（vascular endothelial growth factor,VEGF)旁分泌在肿瘤血管新生中的作用已得到证实,但其自分泌作用尚不清楚。本研究的目的是分析VEGF及其受体（Flt-1和KDR）基因在恶性肿瘤细胞系中的共表达。方法：以看家基因为内标,采用半定量逆转录－聚合酶链反应分析VEGF及其受体基因在30种肿瘤细胞系和4种内皮细胞中的表达水平。结果：在29种肿瘤细胞系和3种内皮细胞系检测到中度以上的VEGF基因表达,而人脐静脉内皮细胞仅有低表达;Flt-1基因表达分别见于50％（6／12）的血液肿瘤,28％（5／18）的实体瘤细胞和2种内皮细胞;仅在16．7％（2／12）的血液肿瘤,33．3％（6／18）实体瘤细胞和2种内皮细胞检测到KDR基因表达;而ECV304细胞并无Flt-1或KDR基因的表达。结论：VEGF基因高表达是肿瘤细胞的重要特征,而VEGF及其受体共表达表明肿瘤细胞系中存在自分泌途径。

Coexpression of vascular endothelial growth factor and its receptors in human tumor cell lines

Background & Objective: Vascular endothelial growth factor (VEGF) play an important role in tumor angiogenesis through a paracrine mechanism, but the importance of its autocrine has not been fully elucidated. This study was designed to explore the gene coexpression pattern of VEGF and its receptors (Flt 1 and KDR) in variety of human malignant cell lines. Methods: After isolation of RNA from thirty tumor cell lines and four endothelial cells, gene expressions of VEGF and its receptors were measured by semi quantitative reverse transcriptase polymerase chain reaction using the transcriptional level of the house keeping gene for internal calibration. Results: VEGF transcript was detected in the majority of tumor cell lines (29/30) and in all endothelial cell lines at moderate or high level, while the expression of VEGF was low in human umbilical vein endothelial cell (HUVEC). Moreover, Flt 1 gene expression was found in 50% of hematopoietic malignancies (6/12), 28% of solid tumors (5/18), and endothelial cells (EA.hy926 and HUVEC). In contrast, the expression of KDR gene was found in 2 (16.7%) hematopoietic cell lines and 6 (33.3%) solid tumor lines. In endothelial cells, KDR gene expression was detectable in HMEC 1 and HUVEC only. However,ECV304 cells express neither Flt 1 nor KDR gene. Conclusion: Overexpression of VEGF gene in all tumor cell lines provides a potential biological marker for malignancies and the coexpression of VEGF with its receptors suggesting an autocrine pathway exists in tumor cells.