Novel aspects of the preclinical pharmacology of platinum compounds

Abstract

Platinum compounds are widely used antitumor agents known to interfere with DNA function by forming DNA crosslinks and DNA-protein crosslinks. Because of their electrophilicity, platinum compounds can interact with nucleophilic residues of all macromolecules. Consequently, this cross-linking inhibits DNA replication in cancer cells. Immunogenic and immunomodulating effects have been ascribed to platinum drugs, with differences and similarities among cisplatin, carboplatin and oxaliplatin. On the one hand, cisplatin is generally unable to induce immunogenic cell death; on the other hand, oxaliplatin appears to be a good inducer, thanks to its capability to efficiently trigger calreticulin exposure to the tumor cell plasma membrane. Conversely, cisplatin, carboplatin and oxaliplatin can relieve immunosuppressive networks e.g., by decreasing PDL-1 and PDL-2 in dendritic and tumor cells. Such drugs are also capable of modulating MHC molecules via IFN-β production and T-cell mediated lysis. The concentrations appear to be key in determining the immunomodulatory properties of these cytotoxic agents, with low in vivo doses usually playing stimulatory effects. As predicted from preclinical models, supportive results have emerged from clinical studies, particularly those based on chemotherapeutic regimens of platinum compounds combined with immunotherapeutics. Future therapeutic interventions are expected to benefit from a better definition of the molecular effects of platinum compounds on the immune system.