Synthesis and evaluation of anticancer activity in cells of novel stoichiometric pegylated fullerene-doxorubicin conjugates.
OBJECTIVE
To synthesize pegylated stoichiometrically and structurally well-defined conjugates of fullerene (C60) with doxorubicin (DOX) and investigate their antiproliferative effect against cancer cell lines.


METHODS
Stoichiometric (1:1 and 1:2) pegylated conjugates of C60 with DOX were synthesized using the Prato reaction to create fulleropyrrolidines equipped with a carboxyl function for anchoring a polyethylene glycol (PEG) moiety and either a hydroxyl group for attaching one molecule of DOX or a terminal alkyne group for attaching two molecules of DOX through a click reaction. In both conjugates, the DOX moieties are held through a urethane-type bond. Drug release was studied in phosphate buffer (PBS, pH 7.4) and MCF-7 cancer cells lysate. The uptake of the conjugates by MCF-7 cancer cells and their intracellular localization were studied with fluorescence microscopy. The antiproliferative activity of the conjugates was investigated using the WST-1 test.


RESULTS
One or two DOX molecules were anchored on pegylated C60 particles to form DOX-C60-PEG conjugates. Drug liberation from the conjugates was significantly accelerated in the presence of tumor cell lysate compared to PBS. The conjugates could be internalized by MCF-7 cells. DOX from the conjugates exhibited much delayed, compared to free DOX, localization in the nucleus and antiproliferative activity.


CONCLUSIONS
Pegylated DOX-C60 conjugates (1:1) and (2:1) with well-defined structure were successfully synthesized and found to exhibit comparable, but with a delayed onset, antiproliferative activity with free DOX against MCF-7 cancer cells. The results obtained justify further investigation of the potential of these conjugates as anticancer nanomedicines.
Laboratory of Synthetic Organic Chemistry, Department of Chemistry, University of Patras, 26504, Patras, Greece.
George E
GE
Magoulas
Marina
M
Bantzi
Danai
D
Messari
Efstathia
E
Voulgari
Chrisostomi
C
Gialeli
Despoina
D
Barbouri
Athanassios
A
Giannis
Nikos K
NK
Karamanos
Dionissios
D
Papaioannou
Konstantinos
K
Avgoustakis
D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage / Q000737:chemistry* / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000188:drug therapy; D049109:Cell Proliferation / Q000187:drug effects; D004317:Doxorubicin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*; D016503:Drug Delivery Systems; D065546:Drug Liberation; D005260:Female; D037741:Fullerenes / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D061986:MCF-7 Cells; D011092:Polyethylene Glycols / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology
D000903:Antibiotics, Antineoplastic; D037741:Fullerenes; D011092:Polyethylene Glycols; D004317:Doxorubicin; C069837:fullerene C60