Protein kinase C alpha-specific peptide substrate graft-type copolymer for cancer cell-specific gene regulation systems.
We recently proposed a novel gene regulation system responding to specifically and abnormally activated intracellular enzymes in diseased cells. In the present study, we focused on protein kinase C (PKC)alpha, which is hyper-activated in most tumor cells, as a trigger for transgene regulation. We prepared cationic copolymers comprising hydrophilic and neutral polymers in main chains and cationic peptide substrates with different contents in side chains. Our copolymer with high peptide content (>3 mol%) condensed with pDNA more weakly than with poly(L-lysine) (pLL) having a similar molecular weight, but gene suppression was nearly identical to that of pLL, probably due to the steric hindrance of the main chains in our copolymer. Steric hindrance of the main chains barely affected the phosphorylation reaction of the pendant peptide. In cell and mouse experiments, higher gene expression was observed in complexes of pDNA with copolymers pended PKC alpha-specific substrate peptide than that in complexes with negative copolymers pended peptide substituted phosphorylation site of serine residues with alanine. These results indicate that our system can recognize intracellular PKC alpha as a trigger to regulate transgene expression, and may be useful for tumor gene therapy.
Toita
Riki
R
Graduate School of Systems Life Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
Kang
Jeong-Hun
JH
Kim
Jong-Hwan
JH
Tomiyama
Tetsuro
T
Mori
Takeshi
T
Niidome
Takuro
T
Jun
Byungdug
B
Katayama
Yoshiki
Y
D000595:Amino Acid Sequence; D000818:Animals; D045744:Cell Line, Tumor; D004247:DNA / Q000008:administration & dosage*; D015972:Gene Expression Regulation, Neoplastic; D015316:Genetic Therapy; D008297:Male; D008545:Melanoma / Q000235:genetics / Q000628:therapy; D051379:Mice; D008807:Mice, Inbred BALB C; D010455:Peptides / Q000737:chemistry*; D010957:Plasmids / Q000008:administration & dosage; D011107:Polylysine / Q000737:chemistry*; D051571:Protein Kinase C-alpha / Q000235:genetics* / Q000378:metabolism; D014162:Transfection
D010455:Peptides; D011107:Polylysine; D004247:DNA; D051571:Protein Kinase C-alpha