The effects of a growth-inhibiting tripeptide, acetylGlu-Ser-GlyNH2 (Ac-ESG), on gene expression and cell cycle progression of two lymphoma cell lines.
BACKGROUND
We recently isolated and characterized a tripeptide, acetylGlu-Ser-GlyNH2 (Ac-ESG), which inhibits proliferation of lymphoid cells. In this paper we describe the effects of Ac-ESG on growth-related gene expression and cell cycle progression in two lymphoma cell lines, Ramos and Molt, representing B and T lymphocytes, respectively.


METHODS
RNA was extracted from Molt and Ramos cells with or without the tripeptide treatment. Gene expression was examined by semi-quantitative RT-PCR and Northern blot hybridization, and cell cycle progression was detected by flow cytometry.


RESULTS
In the Molt cells, p53 gene expression was increased following treatment while c-myc was decreased after treatment shorter than 24 hours; N-ras expression was significantly reduced at picomolar concentration for 24-hour treatment; cyclinD1 and cdk4 expression did not show any change; DNA flow cytometry demonstrated that Molt cells were arrested or delayed predominantly in G2-M. Untreated Ramos cells had higher gene expression levels of c-myc, N-Ras and cdk4 than Molt cells, but lower p53 expression. These cells were not sensitive to Ac-ESG.


CONCLUSIONS
The tripeptide Ac-ESG alters the expression of several growth-related genes in the Molt cell line and brings about an arrest or delay of cells in G2-M.
Liu
Ying
Y
Institute of Pediatric Research, National Hospital, University of Oslo, N-0027 Oslo, Norway. YL4@georgetown.edu
Reichelt
Wenche H
WH
Luna
Luisa
L
Elgjo
Kjell
K
Reichelt
Karl L
KL
D015152:Blotting, Northern; D002051:Burkitt Lymphoma / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases / Q000096:biosynthesis / Q000235:genetics; D004273:DNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects; D006131:Growth Inhibitors / Q000494:pharmacology; D006801:Humans; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D009842:Oligopeptides / Q000494:pharmacology*; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000235:genetics; D018631:ras Proteins / Q000096:biosynthesis / Q000235:genetics
D004273:DNA, Neoplasm; D006131:Growth Inhibitors; C416671:N-acetylglutamyl-seryl-glycinamide; D009842:Oligopeptides; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D016159:Tumor Suppressor Protein p53; C495900:CDK4 protein, human; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases; D018631:ras Proteins