PROTEINS AND PEPTIDES AS TARGETING CARRIERS IN ANTICANCER DRUG DELIVERY: A REVIEW

The treatment of cancer is limited by a number of factors including the low therapeutic index of most chemotherapeutic agents, the emergence of drug- and radiation-resistant tumor cells, tumor heterogeneity and the presence of metastatic disease. One of the means to improve the therapeutic index of drugs is by selective or ‘targeted’ delivery to tumor sites. Tumor-directed therapy has the potential to improve efficacy, by increasing the intratumoral concentration of the targeted agent, and to minimize toxicity by reducing systemic exposure. So far some degree of site-selective delivery has been achieved only with “targeting homing drugs” that specifically recognize their pharmacological target. The specificity of delivery using nanoparticles was initially a coincidental property, active targeting has now become a central concept in cancer therapeutic research. This concept has been developed into practical application using a variety of tumor targeting ligands. This review briefly summarizes the ever increasing evidence to the use of proteins such as monoclonal antibodies (MAbs), bispecific antibodies (BsAbs), Affibody molecules, albumin, transferrin and peptides such as stable microbial toxins and cell penetrating peptides (CPPs) as innovative tumor targeting ligands in anticancer drug delivery systems.