Molecular analysis of selected cell cycle regulatory proteins during aerobic and hypoxic maintenance of human ovarian carcinoma cells.
We have previously reported on the development of an in vitro model system for studying the effect of hypoxia on ovarian carcinoma cell proliferation and invasion (Krtolica and Ludlow, 1996). These data indicate that the cell division cycle is reversibly arrested during the G1 phase. Here, we have continued this study to include the proliferation properties of both aerobic and hypoxic human ovarian carcinoma cells at the molecular level. The growth suppressor product of the retinoblastoma susceptibility gene, pRB, appears to be functional in these cells as determined by SV40 T-antigen binding studies. Additional G1-to-S cell cycle regulatory proteins, cyclins D and E, cyclin-dependent kinases (cdks) 4 and 2, and cdk inhibitors p27 and p18, also appear to be intact based on their apparent molecular weights and cell cycle stage-specific abundance. During hypoxia, there is a decrease in abundance of cyclins D and E, with an increase in p27 abundance. cdk4 activity towards pRB and cdk2 activity towards histone H1 are also decreased. Co-precipitation studies revealed an increased amount of p27 complexing with cyclin E-cdk2 during hypoxia than during aerobic cell growth. In addition, pRB-directed phosphatase activity was found to be greater in hypoxic than aerobic cells. Taken together, a model is suggested to explain hypoxia-induced cell cycle arrest in SKA human ovarian carcinoma cells.
Krtolica
A
A
Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, NY, USA.
Krucher
N A
NA
Ludlow
J W
JW
D000332:Aerobiosis; D000952:Antigens, Polyomavirus Transforming / Q000378:metabolism; D042846:CDC2-CDC28 Kinases; D002453:Cell Cycle / Q000502:physiology*; D002455:Cell Division; D015687:Cell Hypoxia; D019925:Cyclin A / Q000378:metabolism; D019938:Cyclin D1 / Q000378:metabolism; D056742:Cyclin D2; D019927:Cyclin E / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D016213:Cyclins / Q000378:metabolism*; D005260:Female; D016193:G1 Phase; D006801:Humans; D008840:Microfilament Proteins / Q000378:metabolism; D009124:Muscle Proteins; D010051:Ovarian Neoplasms / Q000473:pathology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D016160:Retinoblastoma Protein / Q000378:metabolism*; D013539:Simian virus 40; D014407:Tumor Cells, Cultured
D000952:Antigens, Polyomavirus Transforming; C080336:CCND2 protein, human; D019925:Cyclin A; D056742:Cyclin D2; D019927:Cyclin E; D016213:Cyclins; D008840:Microfilament Proteins; D009124:Muscle Proteins; D011518:Proto-Oncogene Proteins; D016160:Retinoblastoma Protein; C058992:Tagln protein, mouse; D019938:Cyclin D1; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495900:CDK4 protein, human; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases