title: Inhibition of canonical WNT/β-catenin signaling is involved in leflunomide (LEF)-mediated cytotoxic effects on renal carcinoma cells.
abstract: 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).
authors.affiliation: Department of Urology, Sir Run-Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China.
authors.forename: Yicheng
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Biology, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China.
authors.forename: Qiaoli
authors.initials: Q
authors.lastname: Huang
authors.affiliation: Department of Biology, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Department of Urology, Wuyi First People's Hospital, Wuyi, Zhejiang 321200, China.
authors.forename: Yueping
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Plastic Surgery, Sir Run-Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China.
authors.forename: Xian
authors.initials: X
authors.lastname: Hu
authors.affiliation: Department of Biology, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Li
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry; D017209:Apoptosis / Q000187:drug effects; D001343:Autophagy; D002292:Carcinoma, Renal Cell / Q000188:drug therapy*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007555:Isoxazoles / Q000494:pharmacology*; D000077339:Leflunomide; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D009368:Neoplasm Transplantation; D015398:Signal Transduction; D060509:Wnt3A Protein / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051176:beta Catenin / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; C495270:CTNNB1 protein, human; D004791:Enzyme Inhibitors; D007555:Isoxazoles; C555510:WNT3A protein, human; D060509:Wnt3A Protein; D051176:beta Catenin; D000077339:Leflunomide
keywords: WNT/β-catenin signaling; cytotoxicity; leflunomide; renal cell carcinoma