Molecular Chimera in Cancer Drug Discovery: Beyond Antibody Therapy, Designing Grafted Stable Peptides Targeting Cancer.

Background: Several cancer therapies are being developed, and given the variability of different cancer types, the goal of these therapies is to remove the invasive tumor from the body, kill the cancer cells, or else retard the growth. These include chemotherapeutic agents and targeted therapy using small molecules and antibodies. However, antibodies can generate an immune response upon repeated administration, and producing antibodies could be expensive. Purpose: The purpose of this review is to describe different therapeutic approaches utilized for cancer therapy, the current therapeutic approaches, and their limitations. As a novel strategy to combat cancer, designing new stable peptide scaffolds such as cyclotides and sunflower trypsin inhibitors (SFTI) is described. Results: Stable peptides that can target proteins can be used as therapeutic agents. Here, we review the utilization and amalgamation of plant-based peptides with biological epitopes in designing molecules called "Molecular Chimeras" using a grafted peptide strategy. These cyclic peptides can bind to target receptors or modulate protein-protein interactions as they bind with high affinity and selectivity. Grafted peptides also possess better serum stability owing to the head-to-tail cyclization and other structural modifications. Conclusion: Stable cyclic peptides outweigh the other biologicals in terms of stability and manufacturing process. Peptides and peptidomimetics can be used as therapeutic agents, and these molecules provide alternatives for biologicals and small molecule inhibitors as drugs.