Fenbendazole is a broad-spectrum benzimidazole class anthelmintic. It has efficacy against several nematodes and cestodes. It also shows promise against trematodes.
Although fenbendazole does interfere with microtubules, it does not act as a radiosensitizer. This is supported by rigorous comparisons of tumor growth between untreated and fenbendazole-treated groups. Additionally, fenbendazole did not affect the radiation dose-response curves of aerobic and hypoxic EMT6 cells (Figure 1).
Fenbendazole is a broad-spectrum benzimidazole anthelminthic
Fenbendazole is an antiparasitic medication that can treat a wide range of parasites in animals. It is used to treat roundworms, hookworms, lungworms, whipworms, and certain types of tapeworms. It is also being used in humans as part of a cancer treatment method known as the Joe Tippens Protocol. This medication is typically well-tolerated and has not been reported to have any major side effects.
It is made from 5-chloro-2-nitroaniline and benzenethiol by reacting them with an excess of hydrofluoric acid. The product is then reduced with ferrous sulfate-iron powder and cyclized with S-methylcarbamic acid methyl ester to yield fenbendazole.
While fenbendazole is most commonly used to treat parasitic infections in animals, research has shown that it can also slow the growth of human cancer cells. This is believed to be due to its ability to disrupt microtubule polymerization and impede glucose uptake. It is also believed to have a broad-spectrum antiparasitic activity, including against helminths and other worms.
Another potential use for fenbendazole is its ability to inhibit the formation of nitric oxide in cells. Nitric oxide is a signaling molecule that inhibits cell growth and promotes cell death. Researchers believe that fenbendazole’s nitric oxide-inhibiting properties could lead to a new class of drugs that treat a variety of diseases, including cancer. These compounds would have the potential to bypass the problems associated with single-target cancer drugs, which are susceptible to drug resistance.
It is an antitumor agent
Fenbendazole is a commonly used antiparasitic agent that inhibits polymerization of tubulin, which makes up microtubules. These microtubules are a part of the cytoskeleton and provide structure and shape to cells. Fenbendazole also exhibits anticancer effects, including apoptosis, by modulating multiple cell pathways. Its mechanisms of action overlap with those of hypoxia-selective nitroheterocyclic cytotoxins/radiosensitizers and taxanes.
To test the anticancer effects of fenbendazole, we studied its effect on EMT6 solid tumors in mice. These studies were performed in combination with the chemotherapeutic agents docetaxel and radiation. The effects of the combinations were evaluated by measuring tumor growth and comparing survivals. The results indicate that fenbendazole does not significantly alter the growth of unirradiated or irradiated tumors. In addition, the addition of fenbendazole does not increase the effectiveness of docetaxel or radiation.
In contrast, fenbendazole reduced the numbers of irradiated and unirradiated EMT6 tumor cells, as well as the yield-corrected surviving fractions. The surviving fractions of the EMT6 monolayer cultures treated with 2-h or 24-h treatments with fenbendazole were lower than those of control cultures.
A number of people have made claims that fenbendazole can cure cancer, but there is no evidence to support these claims. The nonprofit organization Cancer Research UK told Full Fact that fenbendazole hasn’t gone through clinical trials to determine whether it is effective in humans. This is despite the fact that other anecdotal reports have claimed that cancer patients have experienced remission after taking fenbendazole.
It is a microtubule destabilizing agent
While textbook depictions of cells often show them floating in amorphous bags of liquid, in actuality, cells establish their shape and structure through the cytoskeleton, which is made up of microtubules. These microtubules are primarily made of a protein called tubulin. Benzimidazole carbamates like fenbendazole (FBZ) target this protein to destabilize and inhibit its polymerization, thereby disrupting cell structures. FBZ is an established broad-spectrum benzimidazole anthelmintic drug that is used to treat parasite infections in laboratory animals and pets.
Cancer Research UK reports that there is insufficient evidence that fenbendazole can suppress cancer. However, the ingredient of dog wormers does have some anti-cancer effects in animal studies. These include killing cancer cells that are dividing and blocking tumor growth.
This effect is thought to be a result of fenbendazole’s interaction with the microtubules of the cell. This interaction is mediated by its binding affinity for the -tubulin component of the microtubules. Moreover, it also interferes with the ATP-binding site of the -tubulin subunit.
To test fenbendazole’s ability to inhibit cell growth, a colony formation assay was conducted. Cultures were treated with varying doses of fenbendazole for 2 h, and the number of colonies was recorded. The surviving fractions were then calculated as geometric means +/- SD. Severe hypoxia significantly increased the toxicity of 2-h treatments with fenbendazole, but the survival curves still showed similar patterns.
It is a cytotoxic agent
The benzimidazole carbamate drug fenbendazole interferes with microtubules by binding to the tubulin subunits and inhibiting their polymerization. It has broad antiparasitic activity in humans and animals. It acts on parasites by disrupting the mitotic spindle that separates the chromosomes during cell division. The drug also reduces glycogen stores and ATP production in the parasite. It is a highly effective agent for destroying parasites that cause human diseases.
It has also been shown to slow down cancer cell growth in cell cultures and in mice. In addition, it can suppress RAS-related signaling pathways in cancer cells with a KRAS mutation. However, despite these promising results, there is no evidence from randomized clinical trials that fenbendazole can cure cancer in people. Nevertheless, some anecdotal reports suggest that fenbendazole can improve the outcome of cancer treatment.
To investigate the effects of fenbendazole on tumor growth, we treated EMT6 mice with three daily i.p. injections of fenbendazole or a placebo. Tumors were measured and stratified by volume and compared with controls. Treatment with fenbendazole significantly reduced clonogenicity and colony formation in unirradiated tumors. It did not affect the survival of irradiated tumors, however. In addition, 2-h incubations with fenbendazole did not adversely affect aerobic cell viability. Therefore, the cytotoxic effects of fenbendazole may be dependent on the duration and dose of exposure to the fenben lab fenbendazol