Tayyaba Hasan, Ph.D.
Professor of Dermatology
Professor of Health Sciences and Technology
Biography: Tayyaba Hasan is a Professor of Dermatology at the Wellman Center for Photomedicine, Harvard Medical School (HMS), Massachusetts General Hospital and a Professor of Dermatology at Health Sciences and Technology, a joint program of HMS and the Massachusetts Institute of Technology. She was the founding Director of the Office for Research Career Development at Massachusetts General Hospital until 2011. Dr. Hasan's scientific efforts are focused on photochemistry-based approaches (photodynamic therapy, or PDT) for treatment and diagnosis of disease. The overall strategy is to develop molecular mechanisms and optical imaging-based combination treatment regimens where one treatment arm involves light activation of certain near-infrared-absorbing chemicals. This program identifies various cellular and molecular targets for specific diseases and designs constructs for optimal photochemical treatment effects. The targeting entities include photoactivatable nanoparticles and small molecules. In cancer, the focus malignancies are head and neck, glioma, ovarian, pancreas, and prostate cancers. In infections and infectious diseases, efforts are targeted toward developing microbial-enzyme-specific photoactivatable molecules for use in PDT. Target organisms in the infectious diseases are leishmaniasis, Mycobacterium tuberculosis and methicillin-resistant Staphylococcus aureus. In addition, optimal imaging strategies develop target specific molecular probes for in situ monitoring of cellular processes during treatment such as the up-regulation of vascular endothelial growth factor.
Research and Expertise: Activation of certain chemicals with light leads to photochemical processes that involve the generation of free radicals and excited oxygen species. These molecular species are capable of destroying cells and tissues at or near the areas of photochemistry initiation. An advantage of this approach is that it provides the potential of double selectivity; first, due to the confinement of sites of illumination, and second, due to preferential localization of the activatable chemicals in many neoplastic tissues. Selectivity is further enhanced by delivering the photoactivatable molecules via vehicles such as antibodies and liposomes. The mechanisms of tissue destruction by photochemical processes are different from those used by most cheomtherapeutic drugs. This provides the possibility of using targeted photocemistry in combination with conventional chemotherapy to: 1) destroy cells that are resistant (acquired or intrinsic), and 2) achieve better (broader) tumor response due to the more varied arsenal for attack provided by the combination of photochemical and chemotherapeutic approaches. The best-known biomedical application of photochemical targeting is PDT. Research in our laboratory is focused on the mechanistic, therapeutic, and imaging aspects of photobiology to cancer.