title: Prolactin-regulated apoptosis of Nb2 lymphoma cells: pim-1, bcl-2, and bax expression.
abstract: Lactogen-dependent Nb2 lymphoma cells, widely employed for studying prolactin (PRL) mitogenic mechanisms, are also useful for investigations of apoptosis in T-lineage lymphocytes. Utilizing PRL-dependent Nb2-11 cultures, apoptosis-regulatory genes were evaluated for participation in dexamethasone- (DEX) provoked cell death or its inhibition by PRL. Treatment of lactogen-starved, G1-arrested Nb2-11 cells with DEX (100 nM) activated apoptosis within 12 h evaluated by flow cytometric analysis of fragmented DNA. This effect was not associated with altered expression of bcl-2, bax, or pim-1. PRL (10 ng/mL), coincubated with DEX-treated cells, completely blocked DEX-induced apoptosis. This inhibition was associated with increased expression of bcl-2 and pim-1 mRNAs, genes reported to suppress apoptosis, within 2-6 h after addition of the hormone. Moreover, the increased transcription of bcl-2 and pim-1 was coupled to increases in their protein levels. The results suggest that bcl-2, bax, and pim-1 do not play a critical role in DEX-induced apoptosis in Nb2 cells. However, expression of bcl-2, together with pim-1, may have a role in mediating the antiapoptotic actions of PRL.
authors.affiliation: Department of Pharmacology and Toxicology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Krumenacker
authors.forename: D J
authors.initials: DJ
authors.lastname: Buckley
authors.forename: M A
authors.initials: MA
authors.lastname: Leff
authors.forename: J T
authors.initials: JT
authors.lastname: McCormack
authors.forename: G
authors.initials: G
authors.lastname: de Jong
authors.forename: P W
authors.initials: PW
authors.lastname: Gout
authors.forename: J C
authors.initials: JC
authors.lastname: Reed
authors.forename: T
authors.initials: T
authors.lastname: Miyashita
authors.forename: N S
authors.initials: NS
authors.lastname: Magnuson
authors.forename: A R
authors.initials: AR
authors.lastname: Buckley
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D003907:Dexamethasone / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology; D008223:Lymphoma / Q000473:pathology*; D011388:Prolactin / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D051573:Proto-Oncogene Proteins c-pim-1; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D014407:Tumor Cells, Cultured; D051028:bcl-2-Associated X Protein
chemical_list: C494828:Bax protein, rat; D005938:Glucocorticoids; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D051028:bcl-2-Associated X Protein; D003907:Dexamethasone; D011388:Prolactin; C496637:Pim1 protein, rat; D017346:Protein Serine-Threonine Kinases; D051573:Proto-Oncogene Proteins c-pim-1