TY - JOUR
T1 - Enzyme-activated nanoconjugates for tunable release of doxorubicin in hepatic cancer cells
AU - Medina, Scott H.
AU - Chevliakov, Maxim V.
AU - Tiruchinapally, Gopinath
AU - Durmaz, Yasemin Yuksel
AU - Kuruvilla, Sibu P.
AU - ElSayed, Mohamed E.H.
N1 - Funding Information:
This research is supported by a CAREER Award from the US National Science Foundation and the Translational Research Partnership in Biomedical Engineering Award from Wallace H. Coulter Foundation to Mohamed El-Sayed. Scott H. Medina recognizes the financial support of the Department of Education through a GAANN Fellowship.
PY - 2013/6
Y1 - 2013/6
N2 - We report the synthesis of a series of aromatic azo-linkers (L1-L4), which are selectively recognized and cleaved by azoreductase enzymes present in the cytoplasm of hepatic cancer cells via a NADPH-dependent mechanism. We utilized L1-L4 azo-linkers to conjugate doxorubicin to generation 5 (G5) of poly(amidoamine) dendrimers to prepare G5-L(x)-DOX nanoconjugates. We incorporated electron-donating oxygen (O) or nitrogen (N) groups in the para and ortho positions of L1-L4 azo-linkers to control the electronegativity of G5-L(x)-DOX conjugates and investigated their cleavage by azoreductase enzymes and the associated release of loaded DOX molecules. Hammett σ values of G5-L(x)-DOX conjugates ranged from -0.44 to -1.27, which is below the reported σ threshold (-0.37) required for binding to azoreductase enzymes. Results show that incubation of G5-L1-DOX (σ = -0.44), G5-L2-DOX (σ = -0.71), G5-L3-DOX (σ = -1.00), and G5-L4-DOX (σ = -1.27) conjugates with human liver microsomal (HLM) enzymes and the S9 fraction isolated from HepG2 hepatic cancer cells results in release of 4%-8%, 17%, 60%, and 100% of the conjugated DOX molecules, respectively. These results show that increasing the electronegativity (i.e. lower σ value) of L1-L4 azo-linkers increases their susceptibility to cleavage by azoreductase enzymes. Intracellular cleavage of G5-L(x)-DOX nanoconjugates, release of conjugated DOX molecules, and cytotoxicity correlated with conjugate's electronegativity (σ value) was investigated, with G5-L4-DOX conjugate exhibiting the highest toxicity towards hepatic cancer cells with an IC50 of 13 nm ± 5 nm in HepG2 cells. Cleavage of G5-L(x)-DOX conjugates was specific to hepatic cancer cells as shown by low non-specific DOX release upon incubation with non-enzymatic insect proteins and the S9 fraction isolated from rat cardiomyocytes. These enzyme-activated G5-L(x)-DOX conjugates represent a drug delivery platform that can achieve tunable and cell-specific release of the loaded cargo in hepatic cancer cells.
AB - We report the synthesis of a series of aromatic azo-linkers (L1-L4), which are selectively recognized and cleaved by azoreductase enzymes present in the cytoplasm of hepatic cancer cells via a NADPH-dependent mechanism. We utilized L1-L4 azo-linkers to conjugate doxorubicin to generation 5 (G5) of poly(amidoamine) dendrimers to prepare G5-L(x)-DOX nanoconjugates. We incorporated electron-donating oxygen (O) or nitrogen (N) groups in the para and ortho positions of L1-L4 azo-linkers to control the electronegativity of G5-L(x)-DOX conjugates and investigated their cleavage by azoreductase enzymes and the associated release of loaded DOX molecules. Hammett σ values of G5-L(x)-DOX conjugates ranged from -0.44 to -1.27, which is below the reported σ threshold (-0.37) required for binding to azoreductase enzymes. Results show that incubation of G5-L1-DOX (σ = -0.44), G5-L2-DOX (σ = -0.71), G5-L3-DOX (σ = -1.00), and G5-L4-DOX (σ = -1.27) conjugates with human liver microsomal (HLM) enzymes and the S9 fraction isolated from HepG2 hepatic cancer cells results in release of 4%-8%, 17%, 60%, and 100% of the conjugated DOX molecules, respectively. These results show that increasing the electronegativity (i.e. lower σ value) of L1-L4 azo-linkers increases their susceptibility to cleavage by azoreductase enzymes. Intracellular cleavage of G5-L(x)-DOX nanoconjugates, release of conjugated DOX molecules, and cytotoxicity correlated with conjugate's electronegativity (σ value) was investigated, with G5-L4-DOX conjugate exhibiting the highest toxicity towards hepatic cancer cells with an IC50 of 13 nm ± 5 nm in HepG2 cells. Cleavage of G5-L(x)-DOX conjugates was specific to hepatic cancer cells as shown by low non-specific DOX release upon incubation with non-enzymatic insect proteins and the S9 fraction isolated from rat cardiomyocytes. These enzyme-activated G5-L(x)-DOX conjugates represent a drug delivery platform that can achieve tunable and cell-specific release of the loaded cargo in hepatic cancer cells.
UR - https://www.scopus.com/pages/publications/84875840121
UR - https://www.scopus.com/pages/publications/84875840121#tab=citedBy
U2 - 10.1016/j.biomaterials.2013.02.070
DO - 10.1016/j.biomaterials.2013.02.070
M3 - Article
C2 - 23523429
AN - SCOPUS:84875840121
SN - 0142-9612
VL - 34
SP - 4655
EP - 4666
JO - Biomaterials
JF - Biomaterials
IS - 19
ER -
