Seminar
Tuesday, March 6, 2018 - 12:00am
Graduate student Alexis Apostolos will present
"Photodynamic Therapy: Applications and Advances in Anticancer and Antibacterial Treatments"
on March 6, 2018 at 4:10 PM in Neville Hall, Room 3.
Abstract:
In photodynamic therapy (PDT), a photoresponive compound called a "photosensitizer" absorbs light and transfers this energy to other molecules in the system. More specifically, photosensitizers induce the generation of reactive oxygen species (ROS), which can cause extensive damage to several classes of biomacromolecules when produced in excess in biological systems. The power of this natural process has been harnessed in PDT to combat harmful cells, such as those found in cancer and bacterial, viral, and fungal infections. While some variants of PDT have been clinically approved for cancer, there is still room for further development and improvement in this field. In this seminar, I will discuss three ways in which PDT was applied with aims of treating cancer or bacterial infections. In the first study, a photoresponsive nanovesicle was designed to be selective to low oxygen (hypoxic) environments, characteristic of cancerous tumors. Upon near-infrared (NIR) light irradiation, the nanovesicle disassembled to release tirapazamine (a prodrug that can generate toxic oxidizing radical species through single electron reduction) with the goal of destroying cancerous cells. The second study aimed to solve the issue of severe hypoxia, sometimes produced by photodynamic therapy, which can adversely cause angiogenesis and regrowth of cancerous tumors. An anti-angiogenesis inhibitor, that responds to NIR light via a conjugated photosensitizer was developed and demonstrated significant tumor volume reduction in vivo. In the third study, a current antifolate drug was modified with a photoisomerable moiety in order to be responsive to visible light. The ultimate aim was to combat bacterial infections with enhanced specificity. References: Qian,C.; Feng, P.; Yu, J.; Chen, Y.; Hu, Q.; Sun, W.; Xiao, X.; Hu, X.; Bellotti, A.; Shen, Q.; Gu, Z. Angew. Chem. Int. Ed. 2017, 56-2588-2593. Jung, H.S.; Han, J.; Shi, H.; Koo, S.; Singh, H.; Kim, H.J.; Sessler, J.l.; Lee, J.Y.; Kim J.H.; Kim, J.S. J. Am. Chem. Soc. 2017, 139, 7595-7602. Wegener, M.; Hansen, M.J.; Driessen, A.J.; Szymanski, W.; Feringa, B.L. J. Am. Chem. Soc. 2017, 139, 17979-17986.