Characterization of the cyclin-dependent kinase inhibitory domain of the INK4 family as a model for a synthetic tumour suppressor molecule

• Published in: Oncogene Vol. 16; no. 5; pp. 587 - 596
• Main Authors: FAHRAEUS, R, LAIN, S, BALL, K. L, LANE, D. P
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing 05.02.1998; Nature Publishing Group
• Subjects: Alanine; Alanine - chemistry; Alanine - metabolism; Amino Acid Sequence; Amino acids; Animals; Ankyrins; Antineoplastic Agents - pharmacology; Aspartic acid; Binding Sites; Biological and medical sciences; CDC2-CDC28 Kinases; Cell cycle; Cell Cycle - drug effects; Cell cycle, cell proliferation; Cell physiology; Clonal deletion; Cyclin D; Cyclin D1; Cyclin D1 - antagonists & inhibitors; Cyclin D1 - metabolism; Cyclin E; Cyclin E - antagonists & inhibitors; Cyclin E - metabolism; Cyclin-Dependent Kinase 2; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinase Inhibitor p16 - antagonists & inhibitors; Cyclin-Dependent Kinase Inhibitor p16 - metabolism; Cyclin-dependent kinase inhibitors; Cyclin-dependent kinases; Cyclin-Dependent Kinases - antagonists & inhibitors; Cyclin-Dependent Kinases - metabolism; Enzyme Inhibitors - pharmacology; Fundamental and applied biological sciences. Psychology; Homeobox; Humans; INK4 protein; Kinases; Mice; Molecular and cellular biology; Molecular Sequence Data; p16 Protein; Peptide Fragments - pharmacology; Peptides; Protein Structure, Tertiary; Protein-Serine-Threonine Kinases - antagonists & inhibitors; Protein-Serine-Threonine Kinases - metabolism; Proteins; Proto-Oncogene Proteins; S Phase - drug effects; Tumor suppressor genes; Tumors; Valine; Human; Peptides; Enzyme; Transferases; Enzyme inhibitor; Regulation(control); Cell line; Enzymatic activity; Protein kinase; Cell cycle; Tumor; Inhibition; Fusion protein; Tumor suppressor gene
• ISSN: 0950-9232; 1476-5594
• DOI: 10.1038/sj.onc.1201580

We have previously shown that a 20 amino acid peptide derived from the third ankyrin-like repeat of the p16CDKN2/INK4a (p16) tumour suppressor protein (residues 84-103 of the human p16 protein) can bind to cdk4 and cdk6 and inhibit cdk4-cyclin D1 kinase activity in vitro as well as block cell cycle progression through G1. Substitution of two valine residues corresponding to amino acids 95 and 96 (V95A and V96A) of the p16 peptide reduces the binding to cdk4 and cdk6 and increases its IC0.5 for kinase inhibition approximately threefold when linked to the Antennapedia homeodomain carrier sequence. The same mutations increase the IC0.5 approximately fivefold in the p16 protein. Substitution of aspartic acid 92 by alanine instead increases the binding of the peptide to cdk4 and cdk6 and the kinase inhibitory activity. The p16 peptide blocks S-phase entry in non-synchronized human HaCaT cells by approximately 90% at a 24 microM concentration. The V95A and V96A double substitution minimizes the cell cycle inhibitory capacity of the peptide whereas the D92A substitution increases its capacity to block cell cycle progression. A deletion series of the p16 derived peptide shows that a 10 residue peptide still retains cdk4-cyclin D1 kinase and cell cycle inhibitory activity. The p16 peptide inhibited S-phase entry in five cell lines tested, varying between 47-75%, but had only a limited (11%) inhibitory effect in the pRb negative Saos-2 cells at a concentration of 24 microM. Like the full length p16 protein, the p16 peptide does not inhibit cyclin E dependent cdk2 kinase activity in vitro. These data suggest that acute inhibition of CDK-cyclin D activity by a peptide derived from the INK4 family will stop cells in late G1 in a pRb dependent fashion.