Natural and Synthetic Retinoids: Structural Bases and Biological Effects of Potential Clinical Relevance for the Prevention and Treatment of Infection-Driven Tumors

Retinoids play a critical role in the regulation of cell division, growth, differentiation, and proliferation, and represent an exciting new avenue for targeted therapy of different diseases, including cancer. Natural and synthetic retinoids are also endowed with antiviral properties that make these compounds particularly attractive for the prevention and treatment of infection-driven tumors. In this review, we will summarize the structural bases and the cellular and antiviral effects of retinoids which provide a molecular basis for the management of virus-associated tumors, including Kaposi's sarcoma (HHV-8) and post-transplant lymphoproliferative disorders (EBV). Particular relevance will be given to the selectivity of these retinoids for their cognate receptors (RAR and RXR) in order to establish a link between receptor modulation and antiviral/antitumor effects.