Targeted sialic acid-doxorubicin prodrugs for intracellular delivery and cancer treatment.
OBJECTIVE
To evaluate a novel targeted anticancer prodrug consisting of several copies of sialic acid (SA, targeting moiety), doxorubicin (DOX), citric acid (multifunctional spacer) and poly(ethylene glycol) (PEG, carrier).


METHODS
alpha, omega bis carboxyl PEG was covalently conjugated with multiple copies of SA and DOX through a citric acid spacer and characterized by proton nuclear magnetic resonance ((1)HNMR), matrix-assisted laser desorption/ionization-time of flight (MALDI/TOF), and high-performance liquid chromatography (HPLC). The molecular models of conjugates were established using ChemDraw software. Stability, spontaneous and esterase-stimulated drug release was analyzed by HPLC. Cellular internalization (fluorescence microscopy) and cytotoxicity [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay] of free DOX and prodrugs were evaluated.


RESULTS
(1)HNMR, MALDI/TOF, and HPLC showed the formation of the PEG prodrug conjugates. More than 40% of the drug was released from its conjugate in the presence of esterase enzyme, whereas the conjugate was stable at pH 7.4 in the absence of enzyme. Molecular modeling studies showed stable conformations of conjugates. The targeted prodrug conjugates with two copies of SA and DOX showed enhanced cytotoxicity when compared with non-targeted prodrugs and free DOX.


CONCLUSIONS
Targeting of the conjugate to cancer cells by SA with increased copies of targeting moiety and anticancer drug enhanced prodrug uptake by cancer cells and cytotoxicity of the prodrug.
Department of Pharmaceutics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8020, USA.
Sreeja
S
Jayant
Jayant J
JJ
Khandare
Yang
Y
Wang
Ajay P
AP
Singh
Nicholi
N
Vorsa
Tamara
T
Minko
D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage*; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D004317:Doxorubicin / Q000008:administration & dosage* / Q000737:chemistry; D004355:Drug Stability; D005260:Female; D006801:Humans; D008958:Models, Molecular; D019158:N-Acetylneuraminic Acid / Q000008:administration & dosage* / Q000737:chemistry; D010051:Ovarian Neoplasms / Q000188:drug therapy / Q000473:pathology; D011355:Prodrugs / Q000008:administration & dosage* / Q000737:chemistry
D000903:Antibiotics, Antineoplastic; D011355:Prodrugs; D004317:Doxorubicin; D019158:N-Acetylneuraminic Acid