Antitumor Activity of Fenbendazole in Stage 4 Cancer
The “fenbendazole scandal” in Korea, which resulted from the failure of official health communicators to filter false cancer information, is a bitter reminder that patients often receive misinformation. False cancer information may be spread through social media, which facilitates the diffusion of medically unproven treatments and leads to inappropriate patient behaviors. Patients who self-administer alternative medicines and dietary supplements are at particular risk of this threat, because these patients are less likely to seek out the advice of their physicians.
Several studies have reported the antitumor activity of fenbendazole (FZ) due to its ability to depolymerize microtubules in tumor cells and inhibit mitosis. However, the mechanisms by which fenbendazole exerts these effects remain unclear. In this study, we examined the effect of varying concentrations and durations of FZ on the viability of exponentially growing EMT6 cells in cell culture by using a rigorous colony formation assay. Our results show that incubation of these cells with high concentrations of fenbendazole for 2 and 24 h significantly reduced their clonogenicity. Furthermore, we found that fenbendazole also exhibited cytotoxic effects against these cells, and that these effects were enhanced by severe hypoxia.
We interviewed 21 lung cancer patients with stage one, three, and four for their perceptions of fenbendazole based on semi-structured questions. These participants were asked to describe their acquisition channels of general cancer information and false information, as well as the quality of obtained information. They were also asked about their perceptions of complementary and alternative medicine information, including fenbendazole.
FZ is an effective antiparasitic drug with broad spectrum efficacy and few adverse side effects. It is a member of the class of broad-spectrum benzimidazole antihelmintics, which have been approved for use in many animal species as parasite controllers. Repurposing of these drugs for human use may be an efficient approach to developing new anticancer drugs.
The growth of EMT6 tumors in BALB/cRw mice was compared after stratification of the mean tumor volume at which they were randomly assigned to different treatment groups. Tumors were either untreated, irradiated with 10 Gy of x-rays, treated with three daily i.p. injections of 50 mg/kg/day fenbendazole, or treated with a combination of irradiation and fenbendazole. The growth curves of the tumors were not altered by either treatment alone. However, fenbendazole significantly increased the level of cyclin B1 induced by CDK1 in A549 cells, indicating that it has a cytotoxic as well as a cytostatic activity against these tumors. These data suggest that fenbendazole might be used in conjunction with conventional cancer treatments such as chemotherapies, radiotherapies, and surgery to improve patient outcomes. Isobologram analyses showed that the combination of fenbendazole and docetaxel had additive toxicities, but not synergistic toxicities. This indicates that the mechanism of action of these drugs is different and that a synergistic interaction is unlikely. Moreover, the combination of fenbendazole with conventional cancer therapy is feasible and safe. These observations may help to guide clinical trials of a new antitumor agent. fenbendazole stage 4 cancer