Publication Type Journal Article
Title Carbon-1 versus Carbon-3 Linkage of D-Galactose to Porphyrins: Synthesis, Uptake, and Photodynamic Efficiency
Authors Patricia M. R. Pereira Waqar Rizvi N. V. S. Dinesh K. Bhupathiraju Naxhije Berisha Rosa Fernandes João P. C. Tomé Charles Michael Drain
Groups CCC
Journal BIOCONJUGATE CHEMISTRY
Year 2018
Month February
Volume 29
Number 2
Pages 306-315
Abstract The use of glycosylated compounds is actively pursued as a therapeutic strategy for cancer due to the overexpression of various types of sugar receptors and transporters on most cancer cells. Conjugation of saccharides to photosensitizers such as porphyrins provides a promising strategy to improve the selectivity and cell uptake of the photosensitizers, enhancing the overall photosensitizing efficacy. Most porphyrin carbohydrate conjugates are linked via the carbon-1 position of the carbohydrate because this is the most synthetically accessible approach. Previous studies suggest that carbon-1 galactose derivatives show diminished binding since the hydroxyl group in the carbon-1 position of the sugar is a hydrogen bond acceptor in the galectin-1 sugar binding site. We therefore synthesized two isomeric porphyrin-galactose conjugates using click chemistry: one linked via the carbon-1 of the galactose and one linked via carbon-3. Free base and zinc analogs of both conjugates were synthesized. We assessed the uptake and photodynamic therapeutic (PDT) activity of the two conjugates in both monolayer and spheroidal cell cultures of four different cell lines. For both the monolayer and spheroid models, we observe that the uptake of both conjugates is proportional to the protein levels of galectin-1 and the uptake is suppressed after preincubation with an excess of thiogalactose, as measured by fluorescence spectroscopy. Compared to that of the carbon-1 conjugate, the uptake of the carbon-3 conjugate was greater in cell lines containing high expression levels of galectin-1. After photodynamic activation, MTT and lactate dehydrogenase assays demonstrated that the conjugates induce phototoxicity in both monolayers and spheroids of cancer cells.
DOI http://dx.doi.org/10.1021/acs.bioconjchem.7b00636
ISBN
Publisher
Book Title
ISSN 1043-1802
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Conference Name
Bibtex ID ISI:000426144300011
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