Vinca Alkaloids as Potent Antineoplastic Agents: Mechanism of Action, Clinical Utility and Toxicity

Abstract

The vinca alkaloids are significant natural anticancer drugs primarily extracted from the Madagascar periwinkle (Catharanthus roseus) of the family Apocynaceae. The alkaloids are highly important in modern cancer therapy due to their very potent cytotoxic and antimitotic activity. Vinblastine, vincristine, vindesine, vinorelbine, and vinflunine are the major clinically significant Vinca alkaloids. Vinblastine and vincristine are first-generation Vinca alkaloids; the semi-synthetic vinca alkaloids are vindesine and vinorelbine, and the later-generation vinca alkaloid is vinflunine. The compounds are applied in the treatment of several types of malignancies like leukemia, lymphoma, breast cancer, lung cancer, and other solid tumors. The most important mechanism of action of Vinca alkaloids is the interaction with tubulin, the structural protein of microtubules. They bind to β-tubulin and inhibit tubulin polymerization, which in turn prevents the formation of functional microtubules and the mitotic spindle. Therefore, the alignment and separation of the chromosomes are disturbed, arresting the cell cycle at the metaphase stage and causing apoptosis or cell death. This interference with rapidly dividing cells can be harnessed to make Vinca alkaloids valuable chemotherapeutic agents. Although Vinca alkaloids have therapeutic uses, they can have severe side effects. One characteristic toxicity of this class of drugs is peripheral neurotoxicity, especially seen with vincristine. Neutropenia and other haematological side effects may limit the doses of the drugs vinblastine, vindesine, and vinorelbine. Other toxic effects include gastrointestinal disturbances, autonomic dysfunction, anemia, and more. So, it is essential to carefully consider the dose and monitor during treatment. Overall, Vinca alkaloids are still important anticancer agents, and their unique property of inhibiting microtubule formation is still being utilized in the development of newer anticancer drugs and in cancer chemotherapy. Further research in this field could lead to further improvements in efficacy, toxicity, and therapeutic use in oncology.