K-Ras promotes angiogenesis mediated by immortalized human pancreatic epithelial cells through mitogen-activated protein kinase signaling pathways.
K-Ras promotes angiogenesis mediated by immortalized human pancreatic epithelial cells through mitogen-activated protein kinase signaling pathways.
复制标题
DOI：
10.1158/1541-7786.mcr-08-0577
复制
发表时间：
2009-06
期刊：
影响因子：
--
通讯作者：
Guha S
中科院分区：
文献类型：
--
作者：
Matsuo Y;Campbell PM;Brekken RA;Sung B;Ouellette MM;Fleming JB;Aggarwal BB;Der CJ;Guha S
K-Ras癌基因的激活点突变是胰腺癌中最常见的遗传改变之一，发生在疾病进展的早期。然而，突变型K-Ras活性在肿瘤血管生成中的功能仍然知之甚少。使用人胰管上皮细胞（HPDE）和K-Ras 4BG12 V转化的HPDE细胞（HPDE-KRas），我们发现激活的K-Ras显着增强血管生成因子，包括CXC趋化因子和血管内皮生长因子（VEGF）的生产。Western blot分析显示K-Ras激活促进Raf/丝裂原活化蛋白激酶激酶1/2（MEK1/2）的磷酸化和c-Jun的表达，MEK1/2抑制剂U0126和PD98059显著抑制CXC趋化因子和VEGF的分泌，而c-Jun氨基端激酶抑制剂SP600125仅抑制CXC趋化因子的产生。为了进一步阐明致癌K-Ras在促进血管生成中的生物学功能，我们使用人脐静脉内皮细胞（HUVEC）进行体外侵袭和管形成试验。HUVEC与HPDE-KRas共培养显示出显著增强的侵袭性和管形成，与对照（无共培养）或与HPDE共培养相比。此外，SB225002（CXCR2抑制剂）和2C3（抗VEGF单克隆抗体）单独或以合作的方式显着降低Ras依赖性HUVEC侵袭和管形成的程度。使用另一对永生化的人胰腺导管衍生的细胞，E6/E7/st和其致癌K-Ras变体，E6/E7/Ras/st，获得了类似的结果。两者合计，我们的研究结果表明，血管生成是由旁分泌上皮分泌的CXC趋化因子和VEGF下游的激活致癌K-Ras，并且这种血管成熟部分依赖于MEK 1/2和c-Jun信号。
Activating point mutations in the K-Ras oncogene are among the most common genetic alterations in pancreatic cancer, occurring early in the progression of the disease. However, the function of mutant K-Ras activity in tumor angiogenesis remains poorly understood. Using human pancreatic duct epithelial (HPDE) and K-Ras4BG12V–transformed HPDE (HPDE-KRas) cells, we show that activated K-Ras significantly enhanced the production of angiogenic factors including CXC chemokines and vascular endothelial growth factor (VEGF). Western blot analysis revealed that K-Ras activation promoted the phosphorylation of Raf/mitogen-activated protein kinase kinase-1/2 (MEK1/2) and expression of c-Jun. MEK1/2 inhibitors, U0126 and PD98059, significantly inhibited the secretion of both CXC chemokines and VEGF, whereas the c-Jun NH2-terminal kinase inhibitor SP600125 abrogated only CXC chemokine production. To further elucidate the biological functions of oncogenic K-Ras in promoting angiogenesis, we did in vitro invasion and tube formation assays using human umbilical vein endothelial cells (HUVEC). HUVEC cocultured with HPDE-KRas showed significantly enhanced invasiveness and tube formation as compared with either control (without coculture) or coculture with HPDE. Moreover, SB225002 (a CXCR2 inhibitor) and 2C3 (an anti-VEGF monoclonal antibody) either alone or in a cooperative manner significantly reduced the degree of both Ras-dependent HUVEC invasiveness and tube formation. Similar results were obtained using another pair of immortalized human pancreatic duct–derived cells, E6/E7/st and its oncogenic K-Ras variant, E6/E7/Ras/st. Taken together, our results suggest that angiogenesis is initiated by paracrine epithelial secretion of CXC chemokines and VEGF downstream of activated oncogenic K-Ras, and that this vascular maturation is in part dependent on MEK1/2 and c-Jun signaling.