American Association for Cancer Research
15357163mct140792-sup-137831_2_supp_2932289_nmjllj.pdf (8.2 MB)

Supplementary Figures S1-S8 from Three-Dimensional Cell Culture-Based Screening Identifies the Anthelmintic Drug Nitazoxanide as a Candidate for Treatment of Colorectal Cancer

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journal contribution
posted on 2023-04-03, 14:10 authored by Wojciech Senkowski, Xiaonan Zhang, Maria Hägg Olofsson, Ruben Isacson, Urban Höglund, Mats Gustafsson, Peter Nygren, Stig Linder, Rolf Larsson, Mårten Fryknäs

Supplementary Figures S1-S8. S1. Glucose concentration and pH in spheroid culture medium; S2. Dose-response and time-course experiment; S3. GFP-based and TOX8 assay comparison; S4. HT-29 spheroid-based clonogenic assay; S5. Final hit compounds' effects in spheroids formed with or without medium change S6. Nitazoxanide and tizoxanide effects comparison; S7. Nitazoxanide and irinotecan combination in clonogenic assay; S8. CD44 IHC staining.



Because dormant cancer cells in hypoxic and nutrient-deprived regions of solid tumors provide a major obstacle to treatment, compounds targeting those cells might have clinical benefits. Here, we describe a high-throughput drug screening approach, using glucose-deprived multicellular tumor spheroids (MCTS) with inner hypoxia, to identify compounds that specifically target this cell population. We used a concept of drug repositioning—using known molecules for new indications. This is a promising strategy to identify molecules for rapid clinical advancement. By screening 1,600 compounds with documented clinical history, we aimed to identify candidates with unforeseen potential for repositioning as anticancer drugs. Our screen identified five molecules with pronounced MCTS-selective activity: nitazoxanide, niclosamide, closantel, pyrvinium pamoate, and salinomycin. Herein, we show that all five compounds inhibit mitochondrial respiration. This suggests that cancer cells in low glucose concentrations depend on oxidative phosphorylation rather than solely glycolysis. Importantly, continuous exposure to the compounds was required to achieve effective treatment. Nitazoxanide, an FDA-approved antiprotozoal drug with excellent pharmacokinetic and safety profile, is the only molecule among the screening hits that reaches high plasma concentrations persisting for up to a few hours after single oral dose. Nitazoxanide activated the AMPK pathway and downregulated c-Myc, mTOR, and Wnt signaling at clinically achievable concentrations. Nitazoxanide combined with the cytotoxic drug irinotecan showed anticancer activity in vivo. We here report that the FDA-approved anthelmintic drug nitazoxanide could be a potential candidate for advancement into cancer clinical trials. Mol Cancer Ther; 14(6); 1504–16. ©2015 AACR.