Dual targeting of Raf and VEGF receptor 2 reduces growth and metastasis of pancreatic cancer through direct effects on tumor cells, endothelial cells, and pericytes
Dual targeting of Raf and VEGF receptor 2 reduces growth and metastasis of pancreatic cancer through direct effects on tumor cells, endothelial cells, and pericytes
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DOI：
10.1158/1535-7163.mct-08-0373
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发表时间：
2008-11-01
影响因子：
5.7
通讯作者：
Stoeltzing, Oliver
中科院分区：
文献类型：
--
作者：
Lang, Sven A.;Schachtschneider, Philipp;Stoeltzing, Oliver
Ras/Raf/MEK通路是包括胰腺癌在内的胃肠道恶性肿瘤的重要致癌信号通路。虽然激活B-Raf突变在胰腺癌中并不常见，但我们假设靶向Raf可能对这种癌症实体的治疗有价值。此外，由于血管内皮生长因子受体2 （VEGFR2）参与肿瘤血管生成，我们试图研究Raf和VEGFR2的双重抑制对胰腺肿瘤生长、血管化和转移的影响。采用Western blotting、3-(4,5-二甲基噻唑-2-yi)-2,5-二苯基溴化四唑分析和迁移实验分别检测Raf/VEGFR2抑制剂（NVP-AAL881）对胰腺癌细胞、内皮细胞和血管平滑肌细胞的影响。采用ELISA和/或real-time PCR检测VEGF-A或survivin的表达变化。在原位肿瘤模型中进一步评估了Raf/VEGFR2抑制的生长抑制作用。结果表明，多种Raf亚型在胰腺癌细胞中被激活，nlp - aal881降低了MEK、Akt、Erk和STAT3的激活。此外，Raf/VEGFR2的双重抑制显著降低了VEGF的表达，阻碍了癌细胞的迁移。重要的是，除了阻断vegf诱导内皮细胞中Erk和SAPK的磷酸化外，Raf抑制剂还能减少STAT3的磷酸化，不依赖于VEGFR2的阻断，并降低survivin的表达。内皮细胞和血管平滑肌细胞的增殖和迁移均明显减少。在体内，阻断Raf/VEGFR2可显著抑制原位肿瘤生长和血管化，减少肿瘤转移。综上所述，阻断Raf对胰腺肿瘤细胞、内皮细胞和周细胞具有生长抑制作用，并引发抗血管生成特性。双重靶向Raf和VEGFR2似乎是治疗胰腺癌的有效策略。[j]；7(11):3509 - 18]
The Ras/Raf/MEK pathway represents an important oncogenic signaling pathway in gastrointestinal malignancies, including pancreatic cancer. Although activating B-Raf mutations are infrequent in pancreatic cancer, we hypothesized that targeting Raf could be valuable for therapy of this cancer entity. Moreover, as vascular endothelial growth factor receptor 2 (VEGFR2) is involved in tumor angiogenesis, we sought to investigate the effects of dual inhibition of Raf and VEGFR2 on pancreatic tumor growth, vascularization, and metastasis. Effects of a Raf/VEGFR2 inhibitor (NVP-AAL881) on pancreatic cancer cells, endothelial cells, and vascular smooth muscle cells were determined by Western blotting, 3-(4,5-dimethylthiazol-2-yi)-2,5-diphenyltetrazolium bromide analysis, and migration assays, respectively. Changes in the expression of VEGF-A or survivin were investigated by ELISA and/or real-time PCR. The growth-inhibitory effects of Raf/VEGFR2 inhibition were additionally evaluated in orthotopic tumor models. Results showed that various Raf isoforms were activated in pancreatic cancer cells and NVP-AAL881 diminished the activation of MEK, Akt, Erk, and also STAT3. Moreover, dual inhibition of Raf/VEGFR2 significantly reduced VEGF expression and impaired cancer cell migration. Importantly, besides block-VEGF-induced Erk and SAPK phosphorylation in endothelial cells, the Raf inhibitor diminished STAT3 phosphorylation, independent of a VEGFR2 blockade, and reduced the expression of survivin. In addition, cell proliferation and migration of both endothelial cells and vascular smooth muscle cells were significantly reduced. In vivo, blocking Raf/VEGFR2 significantly inhibited orthotopic tumor growth and vascularization and reduced cancer metastasis. In conclusion, blocking Raf exerts growth-inhibitory effects on pancreatic tumor cells, endothelial cells, and pericytes and elicits antiangiogenic properties. Dual targeting of Raf and VEGFR2 appears to be a valid strategy for therapy of pancreatic cancer. [Mol Cancer Ther 2008;7(11):3509 - 18]