Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Transplantation. 2013 Mar 27;95(6):791-800. doi: 10.1097/TP.0b013e31827fac48.
Sorafenib, a multikinase inhibitor approved for the treatment of advanced renal cell carcinoma and hepatocellular carcinoma, has been reported inhibitory on the function of dendritic cells. This study was aimed to determine the effects of sorafenib on inducing autophagy and immunomodulatory activity and its implication on graft rejection.
Cell viability and surface antigens were examined by 7-amino-actinomycin D and flow cytometric analysis. Autophagy was characterized using light microscopy and transmission electron microscopy for morphology, Western blotting for LC3B-I lipidation and mammalian target of rapamycin signaling molecules, and immunofluorescence staining for endogenous LC3B, GFP-LC3 transfection, and acidic component vacuoles. Skin allograft in mice was used as an experimental transplantation rejection model. Soluble factors contained in culture medium and serum were measured by enzyme-linked immunosorbent assay.
We found that sorafenib inhibited the viability of dendritic cells accompanied by morphologic changes characteristic of autophagy and immature differentiation. This autophagic effect induced by sorafenib was validated by LC3B-I lipidation and autophagosome accumulation. Sorafenib treatment was associated with the down-regulation of phosphorylated mammalian target of rapamycin and its downstream substrate p70S6K. We next performed skin graft model to testify the role of sorafenib-induced immature and autophagic dendritic cells. Intriguingly, sorafenib prolonged the survival of skin allograft without major toxicity. Blockade of autophagic flux by chloroquine partially diminished the protective effect of sorafenib, indicating an autophagy-related mechanism in vivo.
This study suggests that sorafenib, in addition to being an anticancer agent, may have potential to be developed as a new category of immunosuppressant drugs acting via autophagy induction of dendritic cells.
索拉非尼是一种多激酶抑制剂，已被批准用于治疗晚期肾细胞癌和肝细胞癌，据报道其具有抑制树突状细胞功能的作用。本研究旨在确定索拉非尼对诱导自噬和免疫调节活性的影响及其对移植物排斥的影响。
通过 7-氨基放线菌素 D 和流式细胞术分析检测细胞活力和表面抗原。通过光镜和透射电镜观察形态学、LC3B-I 脂质化和哺乳动物雷帕霉素靶蛋白信号分子的 Western 印迹以及内源性 LC3B、GFP-LC3 转染、酸性成分空泡的免疫荧光染色来鉴定自噬。使用小鼠皮肤同种异体移植作为实验性移植排斥模型。通过酶联免疫吸附试验测量培养物和血清中含有的可溶性因子。
我们发现索拉非尼抑制树突状细胞的活力，同时伴有自噬的形态变化和不成熟的分化。这种由索拉非尼诱导的自噬作用通过 LC3B-I 脂质化和自噬体积累得到验证。索拉非尼处理与磷酸化哺乳动物雷帕霉素及其下游底物 p70S6K 的下调有关。我们随后进行了皮肤移植模型实验以验证索拉非尼诱导的不成熟和自噬树突状细胞的作用。有趣的是，索拉非尼延长了皮肤移植物的存活时间而无明显毒性。氯喹阻断自噬流部分减弱了索拉非尼的保护作用，表明体内存在自噬相关机制。
本研究表明，索拉非尼除了作为抗癌药物外，还可能具有通过诱导树突状细胞自噬来开发为新型免疫抑制药物的潜力。
