Peptides from the amino terminal mdm-2-binding domain of p53, designed from conformational analysis, are selectively cytotoxic to transformed cells.
We have synthesized three peptides from the mdm-2 binding domain of human p53, residues 12-26 (PPLSQETFSDLWKLL), residues 12-20, and 17-26. To enable transport of the peptides across the cell membrane and at the same time to maximize the active mdm-2 binding alpha-helical conformation for these peptides, each was attached at its carboxyl terminus to the penetratin sequence, KKWKMRRNQFWVKVQRG, that contains many positively charged residues that stabilize an alpha-helix when present on its carboxyl terminal end. All three peptides were cytotoxic to human cancer cells in culture, whereas a control, unrelated peptide attached to the same penetratin sequence had no effect on these cell lines. The same three cytotoxic peptides had no effect on the growth of normal cells, including human cord blood-derived stem cells. These peptides were as effective in causing cell death in p53-null cancer cells as in those having mutant or normal p53. Peptide-induced cell death is not accompanied by expression of apoptosis-associated proteins such as Bax and waf(p21). Based on these findings, we conclude that the antiproliferative effects of these p53-derived peptides are not completely dependent on p53 activity and may prove useful as general anticancer agents.
Kanovsky
M
M
Department of Pathology and Laboratory Medicine, Harbor Veterans Affairs Medical Center, 800 Poly Place, Brooklyn, NY 11209, USA.
Raffo
A
A
Drew
L
L
Rosal
R
R
Do
T
T
Friedman
F K
FK
Rubinstein
P
P
Visser
J
J
Robinson
R
R
Brandt-Rauf
P W
PW
Michl
J
J
Fine
R L
RL
Pincus
M R
MR
D000595:Amino Acid Sequence; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001665:Binding Sites; D002455:Cell Division / Q000187:drug effects; D002461:Cell Line, Transformed; D005260:Female; D011905:Genes, ras; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D010446:Peptide Fragments / Q000494:pharmacology*; D011336:Probability; D011487:Protein Conformation; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051736:Proto-Oncogene Proteins c-mdm2; D051381:Rats; D013234:Stem Cells / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000494:pharmacology*; D014982:Xenopus laevis
D000970:Antineoplastic Agents; D009687:Nuclear Proteins; D010446:Peptide Fragments; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; C497206:MDM2 protein, human; C497208:Mdm2 protein, rat; D051736:Proto-Oncogene Proteins c-mdm2