Cell-penetrating D-isomer peptides of p53 C-terminus: long-term inhibitory effect on the growth of bladder cancer.
OBJECTIVE
To investigate whether a single application of the membrane-permeable D-isomer of the p53 C-terminus connected with a retro-inverso version of the NH(2)-terminal 20-amino acid peptide of the influenza virus hemagglutinin-2 protein (riHA2) inhibited the growth of bladder cancer cells. The transduction of p53 using poly-arginine is useful for targeting and suppressing the growth of bladder cancer cells. However, the protein's intracellular half-life is short, and repeated application is necessary to achieve an anti-tumor effect.


METHODS
The p53 carboxyl-terminal peptides covalently coupled with cell-penetrating peptides were synthesized with D- or L-amino acids. Moreover, the peptides were connected with riHA2 by a disulfide bridge. Human bladder cancer cell lines were incubated with each peptide and cell viability was assessed with the WST assay. Apoptotic cells were confirmed by Hoechst and active capase-3 staining. The p53 peptides were injected into severe combined immunodeficiency disease mice transplanted with J82 cells to investigate their anti-tumor effect on bladder tumors. A survival curve was plotted using the Kaplan-Meier method.


RESULTS
A single application of cell-penetrating D-isomer peptides of the p53 C-terminus connected with riHA2 (d11R-p53C'-riHA2 and dFHV-p53C'-riHA2) inhibited the growth and induced the apoptosis of bladder cancer cells. The tumor-bearing mice treated only with vehicle had a mean survival time of 12 days, whereas treatment with d11R-p53C'-riHA2 resulted in a long-term survival rate of 50%.


CONCLUSIONS
Peptide transduction therapy using the D-isomer p53 C-terminal peptide with riHA2 may be an innovative method for the treatment of bladder cancer.
Araki
Daiji
D
Department of Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
Takayama
Kentaro
K
Inoue
Miyabi
M
Watanabe
Toyohiko
T
Kumon
Hiromi
H
Futaki
Shiroh
S
Matsui
Hideki
H
Tomizawa
Kazuhito
K
D000818:Animals; D005260:Female; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006801:Humans; D051379:Mice; D009362:Neoplasm Metastasis; D010446:Peptide Fragments / Q000627:therapeutic use*; D013997:Time Factors; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy* / Q000473:pathology*
D019267:Hemagglutinin Glycoproteins, Influenza Virus; D010446:Peptide Fragments; D016159:Tumor Suppressor Protein p53; C526980:influenza virus hemagglutinin peptide 2 (1-23)