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Synthetic Tyr-phospho and non-hydrolyzable phosphonopeptides as PTKs and TC-PTP inhibitors
P Ruzza1, A D Deana, A Calderan
1CNR, Department of Organic Chemistry, University of Padua, Italy.
Abstract:
Tyrosine-specific protein kinases and phosphatases are important signal transducing enzymes in normal cellular growth and differentiation and have been implicated in the etiology of a number of human neoplastic processes. In order to develop agents which inhibits the function of these two classes of enzymes by interfering with the binding of their substrates, we synthesized analogs derived from the peptide EDNEYTA. This sequence reproduces the main autophosphorylation site of Src tyrosine kinases. In this work we report the synthesis, by classical solution methods, of the phosphotyrosyl peptide EDNEYpTA as well as of three analogs in which the phosphotyrosine is replaced by a phosphinotyrosine and by two unnatural, non-hydrolyzable amino acids 4-phosphonomethyl-L-phenylalanine and 4-phosphono-L-phenylalanine. The Src peptide and its derivatives were tested as inhibitors of three non-receptor tyrosine kinases (Lyn, belonging to the Src family, CSK and PTK-IIB) and a non-receptor protein tyrosine phosphatase obtained from human T-cell (TC-PTP). The biomimetic analogues, which do not significantly affect the activity of CSK, PTK-IIB and TC-PTP, act as efficient inhibitors on Lyn, influencing both the exogenous phosphorylation and, especially, its autophosphorylation. In particular, the Pphe derivative may provide a basis for the design of a class of inhibitors specific for Lyn and possibly Src tyrosine kinases, capable of being used in vivo and in vitro conditions.
Insights
Researchers developed novel peptide analogs to inhibit tyrosine kinases, crucial enzymes in cell signaling and cancer. A specific phosphonophenylalanine derivative effectively inhibited Lyn tyrosine kinase, offering potential for targeted cancer therapies.
Area of Science:
- Biochemistry
- Molecular Biology
- Medicinal Chemistry
Background:
- Tyrosine-specific protein kinases and phosphatases regulate cellular processes like growth and differentiation.
- Dysregulation of these enzymes is linked to human cancers.
- Targeting these enzymes is a key strategy for developing anti-cancer agents.
Purpose of the Study:
- To synthesize and evaluate peptide analogs as inhibitors of tyrosine-specific enzymes.
- To design agents that interfere with substrate binding in tyrosine kinases and phosphatases.
- To explore the potential of modified peptides as targeted inhibitors for cancer therapy.
Main Methods:
- Synthesis of phosphotyrosyl peptide EDNEYpTA and its analogs using classical solution methods.
- Modification of phosphotyrosine with phosphinotyrosine and unnatural amino acids (4-phosphonomethyl-L-phenylalanine, 4-phosphono-L-phenylalanine).
- Inhibition assays using non-receptor tyrosine kinases (Lyn, CSK, PTK-IIB) and a human T-cell protein tyrosine phosphatase (TC-PTP).
Main Results:
- The synthesized analogs, particularly the phosphonophenylalanine derivative, showed potent inhibition of Lyn tyrosine kinase.
- These analogs effectively inhibited both exogenous phosphorylation and autophosphorylation of Lyn.
- CSK, PTK-IIB, and TC-PTP activities were not significantly affected by the analogs, indicating specificity.
Conclusions:
- Biomimetic peptide analogs can be designed to specifically inhibit certain tyrosine kinases like Lyn.
- The phosphonophenylalanine derivative shows promise for developing targeted inhibitors for Lyn and potentially Src family tyrosine kinases.
- These inhibitors could be valuable tools for both in vitro and in vivo applications in cancer research and treatment.