[Todos] Seminario INQUIMAE - DQIAQF Viernes 4 de octubre 15hs

[andrea en qi.fcen.uba.ar]

Viernes 4 de octubre , 15 hs
INQUIMAE Aula Seminarios 3er piso.

Light-Activated Metal-based Anticancer Agents
Akhil R. Chakravarty
Department of Inorganic and Physical Chemistry, Indian Institute of
Science,   Bangalore 560 012, India.
E-mail: arc en ipc.iisc.ernet.in

Photodynamic therapy (PDT) is an emerging non-invasive method to treat
cancer. Photo-activation of the drug results in a selective damage of the
cancer cells by producing reactive oxygen species (ROS), viz., singlet
oxygen and/or hydroxyl radicals leaving the unexposed healthy cells
unaffected. While organic compounds like porphyrins and phthalocyanines
are known to show significant photocytotoxicity in visible light forming
singlet oxygen in a type-II pathway, the chemistry of metal-based PDT
agents is relatively unexplored. Biocompatible 3d metal complexes having
versatile coordination geometry, redox and spectral property with low
energy visible band(s) could be suitably designed and synthesized as
potential PDT agents. Such 3d-metal complexes could circumvent the major
drawbacks associated with the macrocyclic organic dye-based PDT agents,
viz., skin and hepatic-toxicity. Recent reports from our laboratory have
shown that 3d-metal complexes of curcumin (Hcur) and related ligands
exhibit significant PDT effect in visible light. Curcumin which is known
for hydrolytic instability in a cellular medium is stabilized on binding
to a metal ion. Curcumin being a fluorescent molecule is suitable for
confocal microscopic imaging studies to investigate the cellular uptake of
the complexes in the cell. The 3d metal complexes are found to show
primarily cytosolic localization in preference to the nuclear localization
thus modeling the cellular uptake properties of Photofrin, the currently
available PDT drug. Cellular organelles like mitochondria or endoplasmic
reticulum as preferred targets in PDT than the nuclear DNA could be
selectively targeted by suitable design of the complexes. The recent
developments in this chemistry would be presented.

Keywords: Metal-based PDT, Cytosolic localization, ROS generation, Apoptosis

[1] Dhar, S.; Senapati, D.; Das, P. K.; Chattopadhyay, P.; Nethaji, M.;
Chakravarty, A. R. J. Am. Chem. Soc. 2003, 125, 12118.
[2] Banerjee, S.; Prasad, P.; Hussain, A.; Khan, I.; Kondaiah, P.;
Chakravarty, A. R. Chem. Commun. 2012, 48, 7702.
[3] Chakravarty, A. R.; Roy, M. Prog. Inorg. Chem. 2012, 57, 119.

Biography:
Akhil R. Chakravarty (b. 1953) received his PhD (1982) from the Calcutta
University under the supervision of Prof. Animesh Chakravorty. He later
joined Texas A&M University (USA) as a post-doctoral fellow under the
supervision of Prof. F.A. Cotton and studied bimetallic complexes having
metal-metal multiple bonds. He joined Indian Institute of Science at
Bangalore, India, in 1985 as an assistant professor and currently is a
Professor in the department of Inorganic and Physical Chemistry.  He is a
Fellow of the Indian Academy of Sciences (FASc), Indian National Science
Academy (FNA) and Academy of Sciences for the Developing World (FTWAS). He
has received the S.S. Bhatnagar Award and is a J.C. Bose national fellow.
He has guided 22 PhD students and published 210 research papers in peer
reviewed journals. His research interests are primarily focused on the
development of the chemistry of metal-based photocytotoxic agents using
bio-compatible 3d metal ions.