Targeted therapeutics have made significant impacts in cancer treatment, resulting in increased efficacy and reduced toxicity. However, many patients with ovarian, triple-negative breast, pancreatic, or lung cancer do not yet have reliable targeted therapeutic options. Mesothelin (MSLN) is a cell surface protein that is overexpressed in numerous cancers, including breast, ovarian, lung, liver, and pancreatic tumors. Aberrant expression of MSLN has been shown to promote tumor progression and metastasis through interaction with established tumor biomarker, CA125. Therefore, molecules that specifically bind to MSLN have potential therapeutic and diagnostic applications. However, no MSLN-targeting molecules are currently approved for routine clinical use. While antibodies that target MSLN are in development, some clinical applications may require a targeting molecule with an alternative protein fold. The Fn3 scaffold has shown great versatility for its ability to be engineered to recognize a variety of targets. Fn3 proteins that bind cell surface protein MSLN have numerous potential clinical applications, such as through diagnostic imaging, internalization for drug delivery, and metastatic reduction by blocking MSLN-MUC16 interactions.
Conjugation of proteins to drug-loaded polymeric structures is an attractive strategy for facilitating target-specific drug delivery for a variety of clinical needs. Polymers currently available for conjugation to proteins generally have limited chemical versatility for subsequent drug loading. Many polymers that do have chemical functionality useful for drug loading are often insoluble in water, making it difficult to synthesize functional protein-polymer conjugates for targeted drug delivery. In our collaborative work, we are conjugating side chain reactive polymers developed by the Buck Lab (Smith College, Department of Chemistry) to engineered non-antibody receptor-targeting proteins, as part of the development of a modular approach to engineer protein-polymer conjugates for drug delivery applications. Our approach to protein-polymer conjugate synthesis offers a simple, tailorable strategy for preparing bioconjugates of interest for a broad range of biomedical applications.
Dr. Maren Buck, Chemistry Department at Smith College: https://www.smith.edu/academics/faculty/maren-buck