title: Poly(ADP-ribose) polymerase activity in proliferating and quiescent murine mammary carcinoma cells.
abstract: Previous studies have shown that the well-oxygenated but nutrient-deprived quiescent (QI) cells of the 67 murine mammary carcinoma line are significantly more sensitive to radiation-induced cell killing than the well-oxygenated proliferating (P) cells. These QI cells also sustain more initial strand breaks per radiation dose and repair them more slowly than do P cells. We now report that NAD+ levels and rates of poly(ADP-ribosylation) show a trend similar in that both these metabolic parameters are lower in QI cells by a factor of two or more. NAD+ levels were measured in acid extracts of intact monolayers using an enzymatic cycling assay, while poly(ADP-ribosylation) was followed through the incorporation of radioactive NAD+ into polymer by permeabilized cells. The major proteins labeled by [32P]NAD+ were the same in P and QI cells. However, qualitative differences exist among minor poly(ADP-ribosylated) proteins, with some bands labeled in P cells but not detectably labeled in QI cells. These studies suggest similarities between the physiological state of QI cells and that of mature resting lymphocytes.
authors.forename: S E
authors.initials: SE
authors.lastname: Sweiger
authors.forename: S J
authors.initials: SJ
authors.lastname: Petzold
authors.forename: C S
authors.initials: CS
authors.lastname: Surowy
authors.forename: S J
authors.initials: SJ
authors.lastname: Berger
authors.forename: L A
authors.initials: LA
authors.lastname: Dethlefsen
authors.forename: N A
authors.initials: NA
authors.lastname: Berger
mesh_terms: D000818:Animals; D002455:Cell Division; D002460:Cell Line; D066298:In Vitro Techniques; D008325:Mammary Neoplasms, Experimental / Q000201:enzymology / Q000473:pathology*; D051379:Mice; D009243:NAD; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*
chemical_list: D009243:NAD; D011065:Poly(ADP-ribose) Polymerases