13C-NMR investigation of protein synthesis during apoptosis in human leukemic cell lines.
In order to evaluate the role of protein synthesis in apoptosis, (13)C-NMR has been used to study the levels of protein synthesis in three different human leukemic cell lines in the presence and absence of dexamethasone-induced apoptosis. Measurements were done on one dexamethasone-sensitive (CEM-C7-14) and two different dexamethasone-resistant variants (CEM-4R4 and CEM-ICR27-4). The incorporation of (13)C-labeled amino acids into cellular proteins, which reflects the level of new protein synthesis, was monitored by (13)C-NMR spectroscopy. In the absence of dexamethasone, the level of protein synthesis was found to be significantly different among the three cell lines. Dexamethasone caused a significant reduction ( congruent with 60-87%) in the level of protein synthesis in dexamethasone-sensitive CEM-C7-14 cells, while having no significant effect on protein synthesis in dexamethasone-resistant CEM-4R4 cells. Dexamethasone treatment caused a significant enhancement of the level of protein synthesis in the CEM-ICR27-4 cells. Synthesis of proteins was found to occur during apoptosis, albeit at a low level, suggesting a role for the synthesis of specific proteins in the mechanism of apoptosis.
Scott
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Department of Chemistry, North Carolina Agricultural and Technical State University, Greensboro, North Carolina 27411, USA.
Adebodun
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D017209:Apoptosis / Q000187:drug effects*; D002247:Carbon Isotopes; D003907:Dexamethasone / Q000494:pharmacology; D005938:Glucocorticoids / Q000494:pharmacology; D006801:Humans; D007938:Leukemia / Q000378:metabolism* / Q000473:pathology; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D014407:Tumor Cells, Cultured
D002247:Carbon Isotopes; D005938:Glucocorticoids; D009363:Neoplasm Proteins; D003907:Dexamethasone