Pim-1 kinase expression during murine mammary development.
Pim-1 kinase phosphorylates substrates whose activities are linked to proliferation, survival, differentiation, and apoptosis. Although pim-1 is induced by hormones and cytokines, the hormonal control and contribution of Pim-1 to mammary gland development have not been evaluated. We examined Pim-1 expression in mammary cell lines, investigated whether Pim-1 levels could be altered in breast epithelia by mammogenic hormones, and evaluated Pim-1 expression during mammary development. We found that Pim-1 was elevated in most mammary carcinoma cell lines and progesterone increased Pim-1 protein to some extent in non-tumorigenic mammary epithelia. Pim-1 expression in situ was consistent with the documented profile of progesterone activity in mouse mammary glands. Pim-1 nuclear localization correlated with cytoplasmic distribution for its substrate, p21(CIP/Waf1), and we found that Pim-1 and p21 associate in vitro. Our results suggest that Pim-1 expression may be regulated by progesterone during mammary development and Pim-1 associates with p21 in mammary epithelial cells.
Gapter
Leslie A
LA
Department of Pharmacy, Faculty of Science, National University of Singapore, 117543, Republic of Singapore.
Magnuson
Nancy S
NS
Ng
Ka-yun
KY
Hosick
Howard L
HL
D000818:Animals; D017209:Apoptosis; D001940:Breast / Q000378:metabolism; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008321:Mammary Glands, Animal / Q000196:embryology* / Q000201:enzymology; D015674:Mammary Neoplasms, Animal / Q000196:embryology* / Q000201:enzymology; D051379:Mice; D051573:Proto-Oncogene Proteins c-pim-1 / Q000096:biosynthesis*
C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D051573:Proto-Oncogene Proteins c-pim-1