BACKGROUND: Nucleoside and nucleobase antimetabolites are an important class of chemotherapeutic agents for the treatment of cancer as well as other diseases. INTRODUCTION: In order to avoid undesirable side effects, several prodrug strategies have been developed for that purpose. In the present review, we describe a relatively unknown strategy that consists in the use of oligonucleotides modified with nucleoside antimetabolites as prodrugs. METHOD: The active nucleotides are generated by enzymatic degradation once incorporated into cells. This strategy has attracted large interest and is very active at present due to the continuous developments made on therapeutic oligonucleotides and the recent advances in the field of nanomaterials and nanomedicine. RESULTS: A large research effort was done mainly in the improvement of the antiproliferative properties of nucleoside homopolymers, but recently, chemically modified aptamers, antisense oligonucleotides and/or siRNA carrying antiproliferative nucleotides have demonstrated a great potential due to the synergetic effect of both therapeutic entities. In addition, DNA nanostructures with interesting properties have been built to combine antimetabolites and enhancers of cellular uptake in the same scaffold. Finally, protein nanoparticles functionalized with receptor-binders and antiproliferative oligomers represent a new avenue for a more effective treatment in cancer therapy. CONCLUSION: It is expected that oligonucleotides carrying nucleoside antimetabolites will be considered as potential drugs in the near future for biomedical applications.

Protein kinases modulate the structure and function of proteins by adding phosphate groups to threonine, tyrosine, and serine residues. The phosphorylation process mediated by the kinases regulates several physiological processes, while their overexpression results in the development of chronic diseases, including cancer. Targeting of receptor tyrosine kinase pathways results in the inhibition of angiogenesis and cell proliferation that validates kinases as a key target in the management of aggressive cancers. As such, the identification of protein kinase inhibitors revolutionized the contemporary anticancer therapy by inducing a paradigm shift in the management of disease pathogenesis. Contemporary drug design programs focus on a broad range of kinase targets for the development of novel pharmacophores to manage the overexpression of kinases and their pathophysiology in cancer pathogenesis. In this review, we present the emerging trends in the development of rationally designed molecular inhibitors of kinases over the last five years (2016-2021) and their incipient role in the development of impending anticancer pharmaceuticals.