Biomedical Engineering Reference
In-Depth Information
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Figure 4.8
Cell membrane translocation mediated by a cell-penetrating peptide
(CPP).
represent a strategy that facilitates DNA import efficiently and nonspecifically
into
cells.
Therefore,
CPPs
have
been
widely
utilized
to
enhance
the
transfection efficiency in current research.
91
The most important classes of CPP are isolated from viruses, such as TAT
(transactivated transcription, an arginine-rich CPP) derived from HIV-1. The
HIV-1 TAT peptide has been successfully used for intracellular gene delivery.
Yamano et al. demonstrated that TAT incorporated with histidine and
cysteine residues and combined with the cationic lipid transfection reagent
FuGENE HD results in very efficient gene transfer in a medium supplemented
with serum across a range of cell lines.
92
Govindarajan et al. conjugated a cell-
penetrating peptide (TAT-Mu) with a targeting ligand (HER2 antibody
mimetic-affibody), resulting in specific TF-knockdown in vitro and regression
of tumors in a xenograft mouse model.
93
Another CPP, KALA (a cationic endosomolytic and fusogenic peptide),
has also been investigated as a gene vector. Chen et al. studied the effect of
KALA on the substrate-mediated gene delivery.
94
A fast degrading cholic
acid functionalized star poly(
DL
-lactide) was used to fabricate calcium
phosphate(Ca-P)/DNA/KALA co-precipitate-deposited films. They found
that this system could rapidly release Ca-P/DNA/KALA to mediate efficient
gene
expression,
and
gene
expression
was
significantly
enhanced
by
the
addition of KALA.
Owing to their intracellular permeability, protein transduction domains
(PTDs) have been widely used to deliver proteins and peptides to mammalian
cells. However, their performance in gene delivery has been relatively poor. To
improve the efficiency of PTD-mediated gene delivery, Min et al. synthesized a
new peptide, KALA-Antp (K-Antp), which contains the sequences for PTD of
the third a-helix of the antennapedia (Antp) homeodomain and the fusogenic
peptide KALA.
95
In this configuration, Antp is designed to provide the
cell permeation capacity and nuclear localization signal, while the KALA
moiety promotes cellular entry of the peptide-DNA complex. An optimal K-
Antp/DNA formula was nearly 400- to 600-fold more efficient than Antp or
