The deworming medicine fenbendazole has received attention in recent weeks from viral videos on Facebook and TikTok that claim to show the drug curing cancer. While animal anthelmintics are widely used to treat parasites in animals, there has been no peer-reviewed study that confirms these medicines could cure human disease. Health Canada lists fenbendazole only for veterinary use. The video clip was made by a Canadian veterinarian, Andrew Jones, who has since been reprimanded for his anti-science approach to pet care and has lost his practice licence.
We examined the effects of fenbendazole on the proliferation and radiation response of EMT6 cancer cells in vitro. Cells were treated with a series of 2-h doses of fenbendazole at various concentrations and then assessed for survival using a colony formation assay. The dose-response curves showed that fenbendazole has a broad cytotoxic and cytostatic effect on tumor cells, with the highest toxicity occurring at concentrations near the limit of solubility. Severe hypoxia during treatment significantly increased the toxicity of fenbendazole, but at concentrations still below its solubility limit, cell viability was not significantly reduced (Figure 1).
Our immunoblotting experiments indicated that fenbendazole stimulates autophagy via Beclin-1 in SNU-C5 and SNU-C5/5-FUR CRC cells. Moreover, we found that fenbendazole activates both p53-mediated apoptosis and necroptosis by phosphorylating RIP and RIP3 and inducing the phosphorylation of MLKL, which is known to activate caspase-8 [35-36]. Interestingly, wild-type p53 but not mutant p53 expression was required for fenbendazole-induced G2/M arrest and apoptosis in SNU-C5 cells. fenbendazole stage 4 cancer