Fenbendazole is a broad-spectrum anthelmintic that also acts as a microtubule inhibitor. It is used to treat gastrointestinal parasites such as pinworms, giardia, roundworms, hookworms, and Taenia solium. It is also known to be a powerful antitumor agent.
Diet treatment was initiated 2 wk before subcutaneous flank implantation of 3 x 107 lymphoma cells. Neither diet supplemented with vitamins alone nor fenbendazole alone caused altered tumor growth, but the group supplemented with both vitamin and fenbendazole showed significant inhibition of tumor growth. The mechanism for this synergy is unknown.
Fenbendazole is a benzimidazole anthelmintic
Fenbendazole is a broad-spectrum anthelmintic drug that effectively treats many parasitic helminths in pet poultry. It is absorbed in the intestinal tract and metabolized in the liver before being eliminated from the body, mostly through feces. It is effective against most ascarids (including Capillaria dissimilis), roundworms, flukes and certain tapeworms in chickens. It is also highly effective against Giardia. In comparison to other anthelmintics used in poultry, fenbendazole has a low residue level in eggs and does not cause resistance in target helminths.
Several benzimidazole compounds are currently being considered for repurposing in cancer therapy because of their antiparasitic properties. We evaluated the cytotoxic effects of a panel of four benzimidazoles, including fenbendazole, parbendazole, oxibendazole and mebendazole, on PC cells and found that they were all potent inhibitors of cell proliferation, with IC50 values in the micromolar to nanomolar range. Lipophilicity was comparable among the compounds, with CLogP values of 4.182 for fenbendazole, 4.072 for parbendazole and 3.795 for oxibendazole and mebendazole.
It is a broad-spectrum anthelmintic
Fenbendazole is a broad-spectrum benzimidazole anthelmintic that can be administered to pigs and other domestic animals. It is effective against the gastrointestinal parasites giardia, roundworms, hookworms, whipworms, the tapeworm genus Taenia (but not Dipylidium caninum), pinworms, and ascarids. It also has been used to treat lungworm infestations in cats and dogs. It can be added to the diet as a dry powder or mixed with water and fed to the animal via drinking water. However, it is important to note that anthelmintics may have a negative impact on diet palatability and may require a withdrawal period before reintroducing the medicated feed.
Social media sites such as Twitter and Facebook have been constructive in disseminating medical information to cancer patients. However, nonmedical individuals have the ability to spread unproven and potentially dangerous information through these sites. This has led to the self-administration of fenbendazole, a popular anthelmintic, by a patient with advanced NSCLC who experienced severe liver injury.
It is a microtubule inhibitor
The benzimidazole carbamates of fenbendazole inhibit tubulin polymerization in parasitic cells. However, they have little effect on the mammalian microtubule network. This is due to the lack of a direct interaction between the drug and mammalian microtubules. To explore the effect of fenbendazole on mammalian microtubules, researchers treated human non-small cell lung carcinoma (NSCLC) cells with 1 uM FZ for 24 h. Afterwards, they examined the cells by immunofluorescence and discovered that the microtubule network was partially altered.
Cancer cells rely on glycolysis for ATP production, and inhibition of glucose metabolism by fenbendazole may enhance oxidative phosphorylation and induce cell death. Therefore, it is important to test the safety of fenbendazole as an antitumor agent in mice.
Two groups of SCID mice were fed a control diet or a diet supplemented with vitamins, fenbendazole, or 2-deoxyglucose (2DG). Both groups developed tumors in the flank, but the tumors of the vitamin plus fenbendazole group were smaller than those of the vitamin-only group.
It is a potent antitumor agent
Bendimidazole anthelmintics, such as fenbendazole, are antiparasitic drugs that also destabilize microtubules. This effect may explain their potent anticancer activity. Several anecdotal stories have been reported on websites of patients with various genitourinary cancers who received fenbendazole in combination with other chemotherapy agents. These anecdotal reports have not been validated, but they indicate that fenbendazole can be a powerful adjunct to conventional cancer therapy.
In experiments in which cultures were made hypoxic by sealing glass culture bottles with rubber gaskets and insertion needles for the influx and efflux of oxygen, fenbendazole caused a dose-dependent decrease in growth rate and cell viability. However, it did not alter the radiation dose-response curves for aerobic or hypoxic cells and did not increase the sensitivity of tumors to docetaxel. In a subsequent experiment, a maximally intensive regimen of three i.p. injections of fenbendazole was administered to mice with EMT6 tumors, and the effects on tumor growth and radiation response were measured.fenben lab fenbendazol