Site-specific DNA-doxorubicin conjugates display enhanced cytotoxicity to breast cancer cells.
Doxorubicin (Dox) is widely used for breast cancer treatment but causes serious side effects including cardiotoxicity that may adversely impact patient lifespan even if treatment is successful. Herein, we describe selective conjugation of Dox to a single site in a DNA hairpin resulting in a highly stable complex that enables Dox to be used more effectively. Selective conjugation of Dox to G15 in the hairpin loop was verified using site-specific labeling with [2-(15)N]-2'-deoxyguanosine in conjunction with [(1)H-(15)N] 2D NMR, while 1:1 stoichiometry for the conjugate was validated by ESI-QTOF mass spectrometry and UV spectroscopy. Molecular modeling indicated covalently bound Dox also intercalated into the stem of the hairpin and stability studies demonstrated the resulting Dox-conjugated hairpin (DCH) complex had a half-life >30 h, considerably longer than alternative covalent and noncovalent complexes. Secondary conjugation of DCH with folic acid (FA) resulted in increased internalization into breast cancer cells. The dual conjugate, DCH-FA, can be used for safer and more effective chemotherapy with Dox and this conjugation strategy can be expanded to include additional anticancer drugs.
Department of Cancer Biology, ‡Department of Molecular Medicine and Translation Science, Wake Forest School of Medicine, and §Department of Biochemistry, Wake Forest School of Medicine , Winston-Salem, North Carolina 27157, United States.
Christopher H
CH
Stuart
David A
DA
Horita
Michael J
MJ
Thomas
Freddie R
FR
Salsbury
Mark O
MO
Lively
William H
WH
Gmeiner
D000903:Antibiotics, Antineoplastic / Q000737:chemistry* / Q000494:pharmacology; D001943:Breast Neoplasms / Q000473:pathology*; D045744:Cell Line, Tumor; D004247:DNA / Q000737:chemistry*; D004317:Doxorubicin / Q000737:chemistry* / Q000494:pharmacology; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy
D000903:Antibiotics, Antineoplastic; D004317:Doxorubicin; D004247:DNA