Isotretinoin as a Multifunctional Anticancer Agent: Molecular Mechanisms, Pharmacological Insights and Therapeutic Potential

ABSTRACT Despite notable advancements in conventional cancer therapies, challenges such as drug resistance, adverse effects, and high treatment costs remain significant obstacles. This situation calls for exploring new therapeutic options. One promising approach is drug repurposing, which uses existing medications with known effects to identify new anticancer agents. Isotretinoin (13‐ cis ‐retinoic acid), a vitamin A derivative typically used to treat severe acne, shows considerable potential as an anticancer agent. Recent studies suggest that isotretinoin has the potential to enhance the efficacy of cancer treatment and contribute to cancer inhibition by targeting specific molecular pathways. This review explores isotretinoin's chemistry, pharmacokinetics, and toxicity, emphasizing its role in cancer treatment through clinical and preclinical studies while elucidating its anticancer mechanisms. Both preclinical and clinical studies have revealed that isotretinoin can effectively inhibit the growth of tumor cells, induce apoptosis, and help regulate cellular differentiation in a range of cancers, including neuroblastoma, glioblastoma, breast, skin, lung, ovarian, cervical, and head and neck cancers. Isotretinoin works against cancer through several mechanisms. It activates retinoic acid receptors (RARs), suppresses oncogenic signaling pathways, and influences gene transcription related to cell cycle control and apoptosis. Moreover, combining isotretinoin with other treatments, like interferon‐alpha, chemotherapy drugs, or other targeted inhibitors, can create synergistic effects that improve treatment effectiveness and potentially lessen side effects. Although isotretinoin holds great promise, we still need more research to address its limitations, such as its toxicity, risks during pregnancy, and differing responses in various cancer types. Current research focuses on optimizing isotretinoin‐based therapies by refining dosage regimens to maximize efficacy and enhancing formulation strategies for improved absorption and reduced side effects. Ultimately, the use of isotretinoin in cancer treatment demonstrates the potential of repurposing established drugs and paves the way for more accessible and cost‐effective cancer therapies.