Phthalocyanine-labeled LDL for tumor imaging and photodynamic therapy

Hui Li; Diane Marotta; Soungkyoo Kim; Britton Chance; Jerry D. Glickson; Theresa M. Busch; Gang Zheng

doi:10.1117/12.573912

18 January 2005 Phthalocyanine-labeled LDL for tumor imaging and photodynamic therapy

Hui Li, Diane Marotta, Soungkyoo Kim, Britton Chance, Jerry D. Glickson, Theresa M. Busch, Gang Zheng

Proceedings Volume 5630, Optics in Health Care and Biomedical Optics: Diagnostics and Treatment II; (2005) https://doi.org/10.1117/12.573912
Event: Photonics Asia, 2004, Beijing, China

Abstract

Current limitation of both near-infrared (NIR) tumor imaging and photodynamic therapy (PDT) is their lack of sufficient tumor-to-tissue contrast due to the relatively non-specific nature of delivering dye to the tumor, which has led to false negatives for NIR imaging and inadequate therapeutic ratio for PDT. Hence, agents targeting “cancer signatures”, i.e. molecules that accumulate selectively in cancer cells, are particular attractive. One of these signatures is low-density-lipoprotein receptor (LDLR), which is overexpressed in many tumors. We have developed pyropheophorbide cholesterol oleate reconstituted LDL as a LDLR-targeting photosensitizer (PS) and demonstrated its LDLR-mediated uptake in vitro and in vivo. To improve the labeling efficiency for achieving high probe/protein ratio, tetra-t-butyl silicon phthalocyanine bearing two oleate moieties at its axial positions, (tBu)₄SiPcBOA, was designed and synthesized. This compound was designed to 1) prevent the PS aggregation; 2) improve the PS solubility in non-polar solvent; and 3) maximize the PS binding to LDL phospholipid monolayer. Using this novel strategy, (tBu)₄SiPcBOA was reconstituted into LDL (r-SiPcBOA-LDL) with a very high payload (500:1 molar ratio). In addition, (tBu)₄SiPcBOA reconstituted acetylated LDL (r-SiPcBOA)-AcLDL with similar payload was also prepared. Since Ac-LDL cannot bind to LDLR, (r-SiPcBOA)-AcLDL can serve as the negative control to evaluate LDLR targeting specificity. For biological evaluation of these new agents, confocal microscopy and in vitro PDT protocols were performed using LDLR-overexpressing human hepatoblastoma G2 (HepG2) tumor model. These studies suggest that LDL serves as a delivery vehicle to bring large amount of the NIR/PDT agents selectively to tumor cells overexpressing LDLR.

Citation Download Citation

Hui Li, Diane Marotta, Soungkyoo Kim, Britton Chance, Jerry D. Glickson, Theresa M. Busch, and Gang Zheng "Phthalocyanine-labeled LDL for tumor imaging and photodynamic therapy", Proc. SPIE 5630, Optics in Health Care and Biomedical Optics: Diagnostics and Treatment II, (18 January 2005); https://doi.org/10.1117/12.573912

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available