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Inhibition of tyrosine protein kinases by the antineoplastic agent adriamycin
A Donella-Deana1, E Monti, L A Pinna
1Dipartimento di Chimica Biologica dell'Universita' di Padova, Italy.
Abstract:
Adriamycin, a lipid-interacting anti-cancer agent, was found to inhibit the phosphorylation of polyGlu/Tyr (4:1) by tyrosine protein kinases either from spleen or expressed by the oncogene of Abelson murine leukemia virus. The dose dependent inhibition by adriamycin is accounted for by competition for the ATP binding site, but it is also deeply influenced by the nature and concentration of the phosphorylatable substrate, suggesting multiple interactions with the enzyme. The phosphorylation at tyrosine residues of cytosolic proteins from cells transformed by Abelson leukemia virus and the autophosphorylation of tyrosine protein kinases are also inhibited by adriamycin. Unlike tyrosine protein kinases most serine/threonine specific protein kinases, with the notable exception of protein kinase-C, appear to be relatively insensitive to adriamycin.
Insights
Adriamycin (an anti-cancer drug) inhibits tyrosine protein kinases by competing for ATP binding sites. This anticancer agent
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- Adriamycin is a lipid-interacting anti-cancer agent.
- Tyrosine protein kinases play crucial roles in cellular signaling and cancer development.
Purpose of the Study:
- To investigate the inhibitory effects of Adriamycin on tyrosine protein kinases.
- To elucidate the mechanism of inhibition and the specificity of Adriamycin's action.
Main Methods:
- In vitro kinase assays using purified tyrosine protein kinases and synthetic substrates.
- Enzyme kinetics to determine the mode of inhibition.
- Analysis of protein phosphorylation in cells transformed by Abelson murine leukemia virus.
Main Results:
- Adriamycin dose-dependently inhibited the phosphorylation of polyGlu/Tyr (4:1) by tyrosine protein kinases.
- Inhibition occurred via competition for the ATP binding site, influenced by substrate concentration and type.
- Adriamycin also inhibited tyrosine phosphorylation of cytosolic proteins and autophosphorylation of tyrosine kinases.
- Serine/threonine protein kinases were largely insensitive, except for protein kinase-C.
Conclusions:
- Adriamycin is a potent inhibitor of tyrosine protein kinases.
- Its inhibitory mechanism involves ATP-site competition and substrate-dependent interactions.
- Adriamycin exhibits selectivity, primarily affecting tyrosine kinases over most serine/threonine kinases.