Ivermectin has powerful antitumor effects, including the inhibition of proliferation, metastasis, and angiogenic activity, in a variety of cancer cells. This may be related to the regulation of multiple signaling pathways by ivermectin through PAK1 kinase. On the other hand, ivermectin promotes programmed cancer cell death, including apoptosis, autophagy and pyroptosis. Ivermectin induces apoptosis and autophagy is mutually regulated. Interestingly, ivermectin can also inhibit tumor stem cells and reverse multidrug resistance and exerts the optimal effect when used in combination with other chemotherapy drugs.
Summary and outlooks
Malignant tumors are one of the most serious diseases that threaten human health and social development today, and chemotherapy is one of the most important methods for the treatment of malignant tumors. In recent years, many new chemotherapeutic drugs have entered the clinic, but tumor cells are prone to drug resistance and obvious adverse reactions to these drugs. Therefore, the development of new drugs that can overcome resistance, improve anticancer activity, and reduce side effects is an urgent problem to be solved in chemotherapy. Drug repositioning is a shortcut to accelerate the development of anticancer drugs.
As mentioned above, the broad-spectrum antiparasitic drug IVM, which is widely used in the field of parasitic control, has many advantages that suggest that it is worth developing as a potential new anticancer drug. IVM selectively inhibits the proliferation of tumors at a dose that is not toxic to normal cells and can reverse the MDR of tumors. Importantly, IVM is an established drug used for the treatment of parasitic diseases such as river blindness and elephantiasis. It has been widely used in humans for many years, and its various pharmacological properties, including long- and short-term toxicological effects and drug metabolism characteristics are very clear. In healthy volunteers, the dose was increased to 2 mg/Kg, and no serious adverse reactions were found, while tests in animals such as mice, rats, and rabbits found that the median lethal dose (LD50) of IVM was 10-50 mg/Kg  In addition, IVM has also been proven to show good permeability in tumor tissues . Unfortunately, there have been no reports of clinical trials of IVM as an anticancer drug. There are still some problems that need to be studied and resolved before IVM is used in the clinic.
(1) Although a large number of research results indicate that IVM affects multiple signaling pathways in tumor cells and inhibits proliferation, IVM may cause antitumor activity in tumor cells through specific targets. However, to date, no exact target for IVM action has been found. (2) IVM regulates the tumor microenvironment, inhibits the activity of tumor stem cells and reduces tumor angiogenesis and tumor metastasis. However, there is no systematic and clear conclusion regarding the related molecular mechanism. Therefore, in future research, it is necessary to continue to explore the specific mechanism of IVM involved in regulating the tumor microenvironment, angiogenesis and EMT. (3) It has become increasingly clear that IVM can induce a mixed cell death mode involving apoptosis, autophagy and pyroptosis depending on the cell conditions and cancer type. Identifying the predominant or most important contributor to cell death in each cancer type and environment will be crucial in determining the effectiveness of IVM-based treatments. (4) IVM can enhance the sensitivity of chemotherapeutic drugs and reduce the production of resistance. Therefore, IVM should be used in combination with other drugs to achieve the best effect, while the specific medication plan used to combine IVM with other drugs remains to be explored.