Fenben for Cancer
Fenben, a broad-spectrum antiparasitic drug used in veterinary medicine to treat parasitic worms in animals, has been shown to reduce cancer cell proliferation in vitro and suppress tumor growth in vivo. It is a member of the class of drugs called benzimidazoles, which are known to be effective against parasitic worms and a variety of cancers in animals and humans. However, it is currently not a part of any standard of care for cancer patients in the US. Claims that fenben cures cancer have spread widely, mostly due to anecdotal stories of people who say they were cured by taking the medication. This is despite the fact that no scientific evidence exists to support these claims.
An investigation of the effects of fenbendazole on cancer cells in petri dishes and mice found that it disrupts microtubule dynamics, prevents p53-mediated apoptosis, and interferes with glucose metabolism. The research, published in the journal Scientific Reports, identifies these effects as the collective underlying mechanisms of fenbendazole-induced preferential elimination of cancer cells both in vitro and in vivo.
In vitro, the survival of exponentially growing EMT6 cells was monitored in the presence or absence of varying concentrations of fenbendazole for 2 h. The results are plotted as survival fractions and yield-corrected surviving fractions (YCSF). The graphs clearly show that the compound is highly cytotoxic when cell numbers are low, with viability dropping rapidly at high doses, then stabilizing as the concentration approaches the limit of solubility. Severe hypoxia increased the toxicity of fenbendazole, but the effect was still much less dramatic than that seen in cultures treated in air.
The researchers also conducted an in vivo study using mice with ovarian tumors. Fenbendazole was administered IV, and tumor growth was measured in the lungs, kidneys, liver, and heart. Mice receiving Fenbendazole and RAPA showed significant growth inhibition compared to controls, which received only placebo. Biodistribution of the drug was also assessed by measuring its levels in organs at 8 h after administration. RAPA was mainly concentrated in the liver and heart, but Fenbendazole was distributed evenly throughout all tissues.
The anthelmintic activity of benzimidazoles is largely associated with inhibition of glucose uptake, which affects the availability of energy for cell growth and proliferation. To determine whether this was an important mechanism of action for fenbendazole in human cancer cells, the enzymatic activity of the glycolytic enzyme hexokinase II (HK II) was examined. Inhibition of HK II by fenbendazole reduced the uptake of the fluorescent glucose analogue 2-NBDG, which reflected alterations in glucose uptake and metabolism. Moreover, the expression of glucose transporters and hexokinase II was reduced by Fenbendazole exposure, which further indicated that fenbendazole affected glucose metabolism in cancer cells.fenben for cancer