As a result of the toxicity of currently available anticancer drugs and the inefficiency of chemotherapeutic treatments, the design and discovery of effective and selective
antitumor agents continues to be a hot topic in organic medicinal chemistry. Targeted
therapy is a newer type of
cancer treatment that uses drugs designed to interfere with specific molecules necessary for
tumor growth and progression. This review explains the mechanism of regulation of
p53 (tumor suppressor protein) by MDM2 and illustrates the role of targeting p53-MDM2
protein-
protein interaction using small molecules as a new
cancer therapeutic strategy. Spirocyclic
oxindoles or
spiro-oxindoles, with a rigid heterocyclic ring fused at the 3-position of the
oxindole core with varied substitution around it, are the most efficacious class of small molecules which inhibit cell proliferation and induce apoptosis in
cancer cells, leading to complete
tumor growth regression without affecting activities of normal cells. In this review, we present a comprehensive account of the systematic development of and recent progress in diverse spiro-
oxindole derivatives active as potent selective inhibitors of p53-MDM2 interaction with special emphasis on spiro-pyrrolidinyl
oxindoles (the MI series), their mechanism of action, and structure-activity relationship. This review will help in understanding the molecular mechanism of p53 reactivation by
spiro-oxindoles in
tumor tissues and also facilitates the design and exploration of more potent analogues with high efficacy and low side effects for the treatment of
cancer. Recent progress in spiro-
oxindole derivatives as potent small molecule inhibitors of p53-MDM2 interaction, useful as
anticancer agents, is described with reference to their mechanism of action and structure-activity relationship.