lithium-chloride and pyrvinium

Wound healing after corneal injury typically involves fibrosis, with transforming growth factor β1 (TGF-β1) as one of its strongest mediators. A class of small molecules-peroxisome proliferator-activated receptor γ (PPARγ) ligands-exert potent antifibrotic effects in the cornea by blocking phosphorylation of p38 mitogen-activated protein kinase (MAPK). However, why this blocks fibrosis remains unknown. Herein, we show that PPARγ ligands (rosiglitazone, troglitazone, and 15-deoxy-Δ12,14-prostaglandin J2) decrease levels of β-catenin. We also show that β-catenin siRNA and the Wingless/integrated (Wnt) inhibitor pyrvinium block the ability of corneal fibroblasts to up-regulate synthesis of α-smooth muscle actin (α-SMA), collagen 1 (COL1), and fibronectin (FN) in response to TGF-β1. Activation of TGF-β receptors and p38 MAPK increased glycogen synthase kinase 3β (GSK3β) phosphorylation, whereas a chemical inhibitor of p38 MAPK (SB203580) reduced the phosphorylation of GSK3β, decreasing active β-catenin levels in both cytoplasmic and nuclear fractions. Finally, lithium chloride, a GSK3 inhibitor, also attenuated the TGF-β1-induced increase in α-SMA, COL1, and FN expression. All in all, our results suggest that TGF-β1 stimulation increases active β-catenin concentration in cultured corneal fibroblasts through p38 MAPK regulation of canonical Wnt/β-catenin signaling, increasing α-SMA, COL1, and FN synthesis. Thus, PPARγ ligands, by blocking TGF-β1-induced p38 MAPK phosphorylation, prevent increases in both total and active β-catenin through p38 MAPK-GSK3β signaling.

Topics: Actins; Animals; beta Catenin; Cats; Chromans; Collagen Type I; Cornea; Fibroblasts; Fibronectins; Fibrosis; Glycogen Synthase Kinase 3 beta; Lithium Chloride; p38 Mitogen-Activated Protein Kinases; Phosphorylation; PPAR gamma; Prostaglandin D2; Pyrvinium Compounds; Receptors, Transforming Growth Factor beta; Rosiglitazone; Signal Transduction; Thiazolidinediones; Transforming Growth Factor beta1; Troglitazone

BACKGROUND Aberrant activation of Wnt/β-catenin has been shown to promote ovarian cancer proliferation and chemoresistance. Pyrvinium, an FDA-approved anthelmintic drug, has been identified as a potent Wnt inhibitor. Pyrvinium may sensitize ovarian cancer cells to chemotherapy. MATERIAL AND METHODS The effect of pyrvinium alone and its combination with paclitaxel in ovarian cancer was investigated using an in vitro culture system and in vivo xenograft models. The mechanisms of its action were also analyzed, focusing on the Wnt/β-catenin pathway. RESULTS Pyrvinium inhibited growth and induced apoptosis of paclitaxel- and cisplatin-resistant epithelial ovarian cancer cell lines A2278/PTX and SK-OV-3. Its combination with paclitaxel was synergistic in targeting ovarian cancer cells in vitro. In 3 independent ovarian xenograft mouse models, pyrvinium alone inhibited tumor growth. More importantly, we observed significant inhibition of tumor growth throughout the treatment when using pyrvinium and paclitaxel combined. Mechanistically, pyrvinium increased the Wnt-negative regulator axin and decreased the b-catenin levels in ovarian cancer cells. In addition, pyrvinium suppressed Wnt/b-catenin-mediated transcription, as shown by the decreased mRNA levels of MYC, cyclin D, and BCL-9. In contrast, the inhibitory effects of pyrvinium were reversed by β-catenin stabilization or overexpression, demonstrating that pyrvinium acted on ovarian cancer cells via targeting the Wnt/β-catenin signaling pathway. CONCLUSIONS We demonstrated that the anthelmintic drug pyrvinium targets ovarian cancer cells through suppressing Wnt/β-catenin signaling. Our work highlights the therapeutic value of inhibiting Wnt/β-catenin in ovarian cancer.

Topics: Animals; Anthelmintics; Antineoplastic Agents; Apoptosis; beta Catenin; Cell Line, Tumor; Cell Proliferation; Drug Resistance, Neoplasm; Drug Synergism; Female; Humans; Lithium Chloride; Mice, SCID; Ovarian Neoplasms; Paclitaxel; Pyrvinium Compounds; Wnt Signaling Pathway