The integrin-linked kinase regulates the cyclin D1 gene through glycogen synthase kinase 3beta and cAMP-responsive element-binding protein-dependent pathways.
The cyclin D1 gene encodes the regulatory subunit of a holoenzyme that phosphorylates and inactivates the pRB tumor suppressor protein. Cyclin D1 is overexpressed in 20-30% of human breast tumors and is induced both by oncogenes including those for Ras, Neu, and Src, and by the beta-catenin/lymphoid enhancer factor (LEF)/T cell factor (TCF) pathway. The ankyrin repeat containing serine-threonine protein kinase, integrin-linked kinase (ILK), binds to the cytoplasmic domain of beta(1) and beta(3) integrin subunits and promotes anchorage-independent growth. We show here that ILK overexpression elevates cyclin D1 protein levels and directly induces the cyclin D1 gene in mammary epithelial cells. ILK activation of the cyclin D1 promoter was abolished by point mutation of a cAMP-responsive element-binding protein (CREB)/ATF-2 binding site at nucleotide -54 in the cyclin D1 promoter, and by overexpression of either glycogen synthase kinase-3beta (GSK-3beta) or dominant negative mutants of CREB or ATF-2. Inhibition of the PI 3-kinase and AKT/protein kinase B, but not of the p38, ERK, or JNK signaling pathways, reduced ILK induction of cyclin D1 expression. ILK induced CREB transactivation and CREB binding to the cyclin D1 promoter CRE. Wnt-1 overexpression in mammary epithelial cells induced cyclin D1 mRNA and targeted overexpression of Wnt-1 in the mammary gland of transgenic mice increased both ILK activity and cyclin D1 levels. We conclude that the cyclin D1 gene is regulated by the Wnt-1 and ILK signaling pathways and that ILK induction of cyclin D1 involves the CREB signaling pathway in mammary epithelial cells.
D'Amico
M
M
Albert Einstein Cancer Center, Departments of Developmental and Molecular Biology Medicine and Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Hulit
J
J
Amanatullah
D F
DF
Zafonte
B T
BT
Albanese
C
C
Bouzahzah
B
B
Fu
M
M
Augenlicht
L H
LH
Donehower
L A
LA
Takemaru
K
K
Moon
R T
RT
Davis
R
R
Lisanti
M P
MP
Shtutman
M
M
Zhurinsky
J
J
Ben-Ze'ev
A
A
Troussard
A A
AA
Dedhar
S
S
Pestell
R G
RG
D051698:Activating Transcription Factor 2; D000818:Animals; D001943:Breast Neoplasms; D018821:CD18 Antigens / Q000502:physiology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002460:Cell Line; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D019938:Cyclin D1 / Q000235:genetics*; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D015972:Gene Expression Regulation, Neoplastic; D038362:Glycogen Synthase Kinase 3; D038341:Glycogen Synthase Kinases; D006801:Humans; D019012:Integrin beta1 / Q000502:physiology; D008321:Mammary Glands, Animal / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D051153:Wnt Proteins; D051155:Wnt1 Protein; D029961:Zebrafish Proteins; D000099200:Scaffold Protein ILK
D051698:Activating Transcription Factor 2; D018821:CD18 Antigens; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D017362:Cyclic AMP Response Element-Binding Protein; D019938:Cyclin D1; D038362:Glycogen Synthase Kinase 3; D038341:Glycogen Synthase Kinases; D019012:Integrin beta1; D017346:Protein Serine-Threonine Kinases; D021122:Protein Subunits; D011505:Protein-Tyrosine Kinases; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; D051153:Wnt Proteins; D051155:Wnt1 Protein; D029961:Zebrafish Proteins; D000099200:Scaffold Protein ILK; C497105:ATF2 protein, human; C497106:Atf2 protein, mouse; C495247:WNT1 protein, human; C495246:Wnt1 protein, mouse