肿瘤靶向治疗新探:多靶点Raf激酶抑制剂

随着对肿瘤分子机制的加深理解，对肿瘤分子靶向治疗的研究已获重大进展。蛋白激酶抑制剂是新近研发的靶向治疗药物之一，通过阻碍细胞内分子传导通路，影响肿瘤细胞的存活、增殖以及疾病进展。在Raf／MEK／ERK信号传导通路中，Raf激酶发挥着至关重要的作用。尽管在正常组织中Raf激酶的功能尚未明朗，但现有的基础及临床研究结果均显示，Raf基因的上调及其蛋白的过度表达存在于多种实体肿瘤之中，包括肾细胞癌、肝细胞癌、黑色素瘤以及非小细胞肺癌等。索拉非尼是全球首个口服的Raf激酶抑制剂。此外，作为一个多靶点药物，索拉非尼同时具有针对包括VEGFR与PDGFR的广泛酪氨酸激酶受体抑制功能。目前美国FDA已经批准索拉非尼用于治疗转移性肾癌。另外，该药物在针对黑色素瘤、肝癌、胰腺癌以及非小细胞肺癌的临床研究中也已经显示出一定的疗效。本综述将简要说明Raf激酶在正常与肿瘤细胞中的功能以及在不同肿瘤中的作用机制，并重点介绍索拉非尼的临床应用及研究。

Advances in the targeted therapy of cancer: multi-targeted Raf kinase inhibitor

Advances in the understanding of cancer at the molecular level have led to much progress in the development of anti-cancer agents. Among the newly invented medications for targeted cancer therapy, protein kinase inhibitors target intracellular molecules crucial in signaling pathways for cancer cell survival, proliferation, and disease progression. The Raf serine/threonine kinases are pivotal molecules within the Raf/mitogen extracellular kinase (MEK)/extracellular signal-related kinase (ERK) signaling pathway. The exact function of Raf in normal human cells is not yet understood; however, preclinical and clinical researches have shown that over expression of Raf gene or overreaction of Raf kinase isoforms have critical roles in many types of solid tumors, including renal cell carcinoma, hepatocellular carcinoma, melanoma, and non-small cell lung cancer (NSCLC). Sorafenib is the first oral, multi-kinase inhibitor that targets the Raf kinases. It also has a broad spectrum activity against other receptor tyrosine kinases associated with vascular endothelial growth factor receptors and platelet-derived growth factor receptors. Sorafenib was recently approved by FDA for use in advanced renal cell cancer, and is currently undergoing active investigation in the treatment of other types of malignancies, such as melanoma, liver cancer, prostate cancer, and NSCLC. In this review, we will illustrate the role of Raf in both normal and malignant cells, the mechanism of sorafenib in the treatment of renal cell carcinoma, as well as clinical data that support its use and further investigation in advanced renal cell carcinoma, melanoma, and other tumor types.