Monoclonal Antibodies Approved for Cancer Therapy

Updates on the mechanisms of toxicities associated with monoclonal antibodies targeting growth factor signaling and immune cells in cancer

Monoclonal antibody (mAb)-based immunotherapy currently is considered to be an optimal therapeutic approach to cancer treatment, either in combination with surgery, radiation, and/or chemotherapy or alone. Various solid tumors and hematological malignancies have been characterized by distinct molecular targets, which could be utilized as innovative anticancer agents. Notably, receptor tyrosine kinases, including HER2, EGFR, VEGFR, and PDGFR, which act as receptors for growth factors, serve as crucial target proteins, expanding their role in the cancer therapeutic market. In contrast to conventional anticancer agents that directly target cancer cells, the advent of immunotherapy introduces novel approaches, such as immune checkpoint blockers (ICBs) and mAbs targeting surface antigens on immune cells in hematological malignancies and lymphomas. While these immunotherapies have mitigated the acquired resistance observed in traditional targeted therapies, they also exhibit diverse toxicities. Herein, this review focuses on describing the well-established toxicities and newly proposed mechanisms of monoclonal antibody toxicity in recent studies. Understanding these molecular mechanisms is indispensable to overcoming the limitations of mAbs-based therapies, facilitating the development of innovative anticancer agents, and uncovering novel indications for cancer treatment in the future.

Engineering a CEACAM1 Variant with the Increased Binding Affinity to TIM-3 Receptor

Background

T-cell immunoglobulin domain and mucin domain-3 (TIM-3) is an inhibitory receptor expressed in a variety of cells, including dendritic cells, T-helper 1 lymphocytes, and natural killer cells. Binding of this protein to its ligand, carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), causes T-cell exhaustion, a specific condition in which effector T cells lose their ability to proliferate and produce cytokines. Blocking this inhibitory receptor is known to be an effective strategy for treating cancer and other related diseases. Therefore, in this study, in order to block the inhibitory receptor of TIM-3, we designed and produced recombinantly a protein with a high binding affinity to this receptor.

Methods

The extracellular domain of CEACAM1 involved in binding to TIM-3 was mutated using R script to obtain a variant with the increased binding affinity to TIM-3. The binding energy of the mutant protein was calculated using the FoldX module. Finally, after recombinant production of the most appropriate CEACAM1 variant (variant 39) in E. coli, its secondary structure was determined by CD spectroscopy.

Results

The binding free energy between variant 39 and TIM-3 decreased from -5.63 to -14.49 kcal/mol, indicating an increased binding affinity to the receptor. Analysis of the secondary structure of this variant also showed that the mutation did not significantly alter the structure of the protein.

Conclusion

Our findings suggest that variant 39 could bind to TIM-3 with a higher binding affinity than the wild-type, making it a proper therapeutic candidate for blocking TIM-3.

The New Treatment Methods for Non-Hodgkin Lymphoma in Pediatric Patients

One of the most common cancer malignancies is non-Hodgkin lymphoma, whose incidence is nearly 3% of all 36 cancers combined. It is the fourth highest cancer occurrence in children and accounts for 7% of cancers in patients under 20 years of age. Today, the survivability of individuals diagnosed with non-Hodgkin lymphoma varies by about 70%. Chemotherapy, radiation, stem cell transplantation, and immunotherapy have been the main methods of treatment, which have improved outcomes for many oncological patients. However, there is still the need for creation of novel medications for those who are treatment resistant. Additionally, more effective drugs are necessary. This review gathers the latest findings on non-Hodgkin lymphoma treatment options for pediatric patients. Attention will be focused on the most prominent therapies such as monoclonal antibodies, antibody–drug conjugates, chimeric antigen receptor T cell therapy and others.

Anti-EGFR antibody 528 binds to domain III of EGFR at a site shifted from the cetuximab epitope

Antibodies have been widely used for cancer therapy owing to their ability to distinguish cancer cells by recognizing cancer-specific antigens. Epidermal growth factor receptor (EGFR) is a promising target for the cancer therapeutics, against which several antibody clones have been developed and brought into therapeutic use. Another antibody clone, 528, is an antagonistic anti-EGFR antibody, which has been the focus of our antibody engineering studies to develop cancer drugs. In this study, we explored the interaction of 528 with the extracellular region of EGFR (sEGFR) via binding analyses and structural studies. Dot blotting experiments with heat treated sEGFR and surface plasmon resonance binding experiments revealed that 528 recognizes the tertiary structure of sEGFR and exhibits competitive binding to sEGFR with EGF and cetuximab. Single particle analysis of the sEGFR-528 Fab complex via electron microscopy clearly showed the binding of 528 to domain III of sEGFR, the domain to which EGF and cetuximab bind, explaining its antagonistic activity. Comparison between the two-dimensional class average and the cetuximab/sEGFR crystal structure revealed that 528 binds to a site that is shifted from, rather than identical to, the cetuximab epitope, and may exclude known drug-resistant EGFR mutations.