Breast cancer is the most prevalent cancer among women besides non-melanoma skin cancer. Even when caught in early stages, the treatment for breast cancer is often accompanied by harsh and debilitating side effects. For better quality of life, treatment options that have minimal side effects but maintain effectiveness are invaluable. If such a treatment option is a targeted form of therapy, it could selectively treat cancerous cells and not healthy cells. Photodynamic therapy (PDT) is a relatively new light-based therapy that utilizes inherent photochemical properties of certain dyes called photosensitizers (PS) in order to kill cancerous cells. It shows great promise as an alternative therapy for breast cancer with temporary photosensitivity as the only main side effect. The goal of this research was to make a molecularly targeted agent for photodynamic therapy of breast cancer by reliable and replicable methods. This was done through the use of a breast cancer targeting peptide called 18-4 discovered by Dr. Kamaljit Kaur, the synthesis of which was modified within our lab to be done on Sieber resin by solid phase peptide synthesis (SPPS). To this peptide, a tetra-pyrrole dye based on 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH), was conjugated to form a molecularly targeted photosensitizer (MTPS). This was accomplished by two different approaches, the first by conjugation at the third residue of lysine on the 18-4 decapeptide. The second was by the addition of a puzzle piece based on a modular method developed earlier in our lab, which was the PS dye attached to side chain of a lysine residue. These two single modal compounds are the first reported MTPS agents that utilize 18-4 for the molecularly targeted photodynamic therapy of breast cancer and will be tested, along with a Cy5.5-3S analog of the MTPS agents, by our collaborators at the University of Rochester in the PDT of breast cancer models in mice.
Department, Program, or Center
School of Chemistry and Materials Science (COS)
Shaut, Sara, "Light Directed Targeted Photodynamic Therapy of Breast Cancer" (2022). Thesis. Rochester Institute of Technology. Accessed from
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