Chromene-based compounds as drug candidates for renal and bladder cancer therapy - A systematic review

Renal (RC) and bladder cancers (BC) are common urological malignancies prevalent in the male population. Incidence and mortality rates are expected to increase in the near future. Drug toxicity and development of drug resistance in both diseases are major obstacles to achieve successful treatments. Chromenes are heterocyclic compounds constituted by a benzene ring fused to a pyran nucleus. Natural and synthetic chromene-based compounds have proven to be promising anticancer agents. Additionally, re-sensitization of cancer cells to classical treatments has also been demonstrated. Thus, the aim of this systematic review is to assess the potential of chromene-based compounds in the treatment of RC and BC. Study collection was performed in six different databases, to compile existing information on preclinical (in vitro and in vivo) and clinical studies developed to date. Overall, multiple chromene-based compounds showed potent anticancer effects, affecting several biological features such as reduction in cell viability, proliferation, migration and invasion in vitro, and induction of cell cycle arrest and cell death. Tumor volume and weight were generally decreased in vivo upon chromene-based treatment. Modest results have been obtained in two clinical trials, with reports of a partial response and two objective responses in RC patients. Thus, the chromene family can be considered an attractive chemical scaffold, harboring promising drug candidates for RC and BC therapeutics.