| dc.description.abstract | Cancer remains one of the leading causes of death worldwide. Despite the widespread use and clinical effectiveness of traditional anti-cancer treatments, there are significant drawbacks in their use, such as their lack of specificity, toxicity, resistance to treatment and relapse in disease. Therefore, there is a need for alternative anti-cancer therapies that are more targeted to cancer and less toxic to the patient. Immunotherapy utilizes the immune system to selectively target cancer cells. Granzyme B (GrB), a serine protease secreted by cytotoxic T lymphocytes (CTL) and natural killer cell, induces apoptosis in cancer cells. This study aims to develop a drug delivery system for GrB, simulating the CTL-mediated transport to target cancer cells.
Nanogels were synthesized to serve as vehicles for GrB, by incorporating a negative charge on the nanogel, positively charged GrB can be loaded via electrostatic interactions. A polycation coating was synthesized to enable the loaded nanogel to enter the tumoral intracellular environment. This polycation coating contained protected thiol groups that could be deprotected, allowing formation of disulfide cross-links. The cross-linked structure retains GrB in the nanogel under physiological conditions and releases it in the reductive environment of the cell. Nanogels loaded with lysozyme as a model protein, as well as GrB, were characterized for size and zeta potential. Furthermore, loading studies, release studies and fluorescence correlation spectroscopy were performed.
Anionic nanogels were successfully synthesized and demonstrated the ability to load granzyme B (GrB) via electrostatic interactions. The polycation coating was also successfully synthesized and allowed the production of the coated nanogel for further study. Unexpectedly, the GrB appeared to release under physiological conditions. There was no observed triggered GrB release under reductive conditions. Fluorescence correlation spectroscopy was not performed due to GrB protein aggregation.
In conclusion, we successfully designed a delivery system that can effectively load GrB and feature a polymer coating mimicking CTL cell-mediated transport. Future studies need to be done to refine the polycation coating and analyze alternative methods to investigate the controlled release of GrB. Ultimately, enhancing the potential of this delivery system to offer a more effective and less toxic alternative for cancer patients. | |
