Inhibition of canonical WNT/β-catenin signaling is involved in leflunomide (LEF)-mediated cytotoxic effects on renal carcinoma cells.
Inhibition of canonical WNT/β-catenin signaling is involved in leflunomide (LEF)-mediated cytotoxic effects on renal carcinoma cells.
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DOI：
10.18632/oncotarget.10409
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发表时间：
2016-08-02
期刊：
影响因子：
--
通讯作者：
Li T
中科院分区：
文献类型：
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作者：
Chen Y;Huang Q;Zhou H;Wang Y;Hu X;Li T
来氟米特（LEF）是嘧啶生物合成途径中二氢乳清酸脱氢酶（DHODH）的抑制剂，是一种免疫调节剂，被批准用于治疗类风湿关节炎。在这项研究中，我们表明，LEF显着降低肾癌细胞的细胞增殖，在浓度依赖性的方式。50 μM的LEF诱导S期阻滞和自噬。高剂量LEF（>50 μM）可有效诱导细胞凋亡。调节LEF的浓度导致对与细胞周期、凋亡和自噬相关的调节蛋白的表达的明显影响。特别是，高浓度的LEF通过促进β-catenin的核质穿梭和蛋白酶体依赖性降解来抑制经典的WNT信号传导。机制研究表明，AKT激活的抑制部分解释了LEF介导的WNT抑制。基因表达谱芯片显示LEF处理显著抑制了介导WNT/β-catenin激活的受体FZD 10基因的表达。NOD/SCID小鼠体内异种移植研究进一步验证了LEF对肿瘤生长和Wnt/β-catenin信号传导的抑制作用。然而，LEF处理也引发细胞自噬并提高WNT 3a的表达，这改善了其细胞毒性作用。LEF与WNT抑制剂IWP-2或自噬抑制剂HCQ的组合可以产生增强的抗肿瘤结果。总之，这些结果确定了LEF在肾细胞癌（RCC）化疗中的潜在效用和药理学特征。
Leflunomide (LEF), an inhibitor of dihydroorotate dehydrogenase (DHODH) in pyrimidine biosynthetic pathway, is an immunomodulatory agent approved for the treatment of rheumatoid arthritis. In this study, we show that LEF significantly reduced cell proliferation of renal carcinoma cells in a concentration-dependent manner. LEF at 50 μM induced S-phase arrest and autophagy. Higher doses of LEF (>50 μM) effectively induced cell apoptosis. Modulating the concentration of LEF resulted in distinct effects on the expression of regulatory proteins associated with cell cycle, apoptosis, and autophagy. In particular, high concentrations of LEF inhibited canonical WNT signaling by promoting nucleo-cytoplasmic shuttling and proteasome-dependent degradation of β-catenin. Mechanistic studies showed that the repression of AKT activation partly accounted for LEF-mediated WNT inhibition. Gene expression microarray revealed that LEF treatment greatly inhibited the expression of FZD10 gene, a receptor mediating WNT/β-catenin activation. In vivo xenograft study in NOD/SCID mice further validated the inhibitory effects of LEF on tumor growth and Wnt/β-catenin signaling. However, LEF treatment also triggered cell autophagy and elevated the expression of WNT3a, which ameliorated its cytotoxic effects. The combination of LEF with a WNT inhibitor IWP-2 or autophagy inhibitor HCQ could yield an enhanced anti-tumor outcome. Taken together, these results identify the potential utility and pharmacological feature of LEF in the chemotherapy of renal cell carcinoma (RCC).