Regulation of vascular endothelial growth factor expression in human colon carcinoma cells by activity of src kinase
Regulation of vascular endothelial growth factor expression in human colon carcinoma cells by activity of src kinase
复制标题
DOI：
10.1016/s0039-6060(97)90044-1
复制
发表时间：
1997-08-01
期刊：
影响因子：
3.8
通讯作者：
Gallick, GE
中科院分区：
文献类型：
--
作者：
Fleming, RYD;Ellis, LM;Gallick, GE
背景c-src原癌基因编码蛋白酪氨酸激酶pp 60（c-src），其是许多信号转导途径中的介体。其中涉及pp 60（c-src）蛋白酪氨酸激酶活性的一种途径涉及血管内皮生长因子（VEGF）的调节，VEGF是对生长中肿瘤的新血管形成重要的血管生成因子。最近，我们证明结肠肿瘤细胞中pp 60（c-src）活性的降低有助于VEGF表达的降低。本研究检测了结肠肿瘤细胞系中pp 60（C-src）活化细胞密度和VEGF产生之间的关系。将亲代HT-29结肠腺癌细胞和通过用c-SRC反义和有义（对照）表达载体转染产生的稳定亚克隆在稀疏（2 x 10（4）个细胞/cm（2））和融合（20 x 10（4）个细胞/cm（2））条件下接种并生长36小时。提取细胞蛋白质和RNA，测定pp 60（c-src）水平、c-Src酪氨酸激酶活性和VEGF mRNA表达。与稀疏条件下生长的细胞相比，在融合条件下生长的HT-29细胞和对照正义转染克隆的pp 60（c-src）激酶活性增加了3倍至5倍。相反，在反义转染子中，汇合培养条件增加pp 60（c-src）活性的能力减弱。通过回归分析，发现VEGF表达与pp 60-（c）（src）水平直接相关（r（2）= 0. 886）.结论。HT-29细胞密度对c-src激酶活性和VEGF表达的调节有重要作用。当反义转染子中pp 60（c-src）的稳态水平降低时，不仅VEGF的稳态水平降低，而且汇合刺激pp 60（c-src）活性和VEGF产生的能力也降低。这些数据表明，c-src可能是一个中介的组成和I诱导途径的VEGF在结肠肿瘤细胞的生产。
Background. The c-src protooncogene encodes a protein tyrosine Kinase, pp60(c-src), that is a mediator in many signal transduction pathways. One pathway in which pp60(c-src) protein tyrosine kinase activity is implicated involves regulation of vascular endothelial growth factor (VEGF) an angiogenic factor important to neovascularization of growing tumors. Recently we demonstrated that decreased activity of pp60(c-src) in colon tumor cells contributes to decreased expression of VEGF. This study examined the relationship between pp60(C-src) activation cell density, and VEGF production in a colon tumor cell line.Methods. Parental HT-29 colon adenocarcinoma cells and stable subclones created by transfection with c-src antisense and sense (control) expression vectors were plated under sparse (2 x 10(4) cells/cm(2)) and confluent (20 x 10(4) cells/cm(2)) conditions and grown for 36 hours. Protein and RNA were extracted from cells to determine pp60(c-src) levels c-Src tyrosine kinase activity, and VEGF mRNA expression.Results. The pp60(c-src) kinase activity of HT-29 cells and control sense-transfected clones grown under confluent conditions was increased threefold to fivefold compared with cells grown under sparse conditions. In contrast, the ability of confluent culture conditions to increase pp60(c-src) activity was blunted in antisense transfectants. By regression analysis, VEGF expression was found to vary directly with pp60-(c) (src) levels (r(2) = 0. 886).Conclusions. Cell density contributes to the regulation of c-src kinase activity and VEGF expression in HT-29 cells. When the steady-state level of pp60(c-src) is reduced in antisense transfectants, not only is the steady-state level of VEGF reduced, but the ability of confluence to stimulate pp60(c-src) activity and VEGF production is too. These data suggest that c-src may be an intermediary of both constitutive and I inducible pathways for VEGF production in colon tumor cells.