Comparison of potential markers of farnesyltransferase inhibition.
Farnesyltransferase inhibitors (FTIs) were developed to target abnormal signaling pathways that are commonly activated in neoplastic cells. Five FTIs have recently undergone Phase I testing; and two are currently in Phase II clinical trials. As part of the development of these agents, there has been interest in determining their cellular effects in the clinical setting. Several approaches have been proposed, including measurement of FT enzymatic activity, evaluation of the processing of FT polypeptide substrates, and assessment of the accumulation of p21waf1. In the present study, a number of these assays have been compared in four cultured human neoplastic cell lines of different histology (A549, HCT116, BxPC-3, and MCF-7) after treatment with the nonpeptidomimetic FTI SCH66336 and the peptidomimetic inhibitor FTI-277. Immunoblotting studies failed to demonstrate a mobility shift in ras proteins or increased accumulation of p21waf1 after treatment with these agents. In contrast, drug-induced increases in the slower migrating, unprocessed species of the chaperone protein HDJ-2 and the intranuclear intermediate filament protein lamin A were detected in all four cell lines after treatment with either agent. Unprocessed forms of both polypeptides accumulated in noncycling as well as cycling cells. The precursor peptide that is present in prelamin A but absent from mature lamin A could be readily detected by immunohistochemistry in noncycling cells with a peptide-specific antiserum. Our results indicate that unprocessed HDJ-2 and prelamin A should be suitable markers of FT inhibition in clinical samples.
Adjei
A A
AA
Division of Medical Oncology, Mayo Clinic, Rochester, Minnesota 55905, USA. Adjei.Alex@Mayo.edu
Davis
J N
JN
Erlichman
C
C
Svingen
P A
PA
Kaufmann
S H
SH
D019883:Alkyl and Aryl Transferases / Q000037:antagonists & inhibitors*; D000595:Amino Acid Sequence; D000970:Antineoplastic Agents / Q000494:pharmacology*; D014408:Biomarkers, Tumor; D002352:Carrier Proteins / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D051231:Farnesyltranstransferase; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D020128:Inhibitory Concentration 50; D034904:Lamin Type A; D034882:Lamins; D008715:Methionine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D010455:Peptides / Q000737:chemistry; D010880:Piperidines / Q000494:pharmacology*; D011498:Protein Precursors / Q000378:metabolism; D017368:Protein Prenylation; D011725:Pyridines / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection; D014407:Tumor Cells, Cultured; D003986:Dibenzocycloheptenes
D019883:Alkyl and Aryl Transferases; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D002352:Carrier Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D051231:Farnesyltranstransferase; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D034904:Lamin Type A; D034882:Lamins; D008715:Methionine; D009687:Nuclear Proteins; D010455:Peptides; D010880:Piperidines; D011498:Protein Precursors; D011725:Pyridines; C493956:CDKN1A protein, human; C107481:DNAJA1 protein, human; C096856:FTI 277; C090764:prelamin A; C115354:lonafarnib; D003986:Dibenzocycloheptenes