Tumoral Vitamin D Synthesis by CYP27B1 1-α-Hydroxylase Delays Mammary Tumor Progression in the PyMT-MMTV Mouse Model and Its Action Involves NF-κB Modulation.
Biologically active vitamin D (1,25-dihydroxycholecalciferol or 1,25(OH)2D) is synthetized from inactive prohormone 25-hydroxycholecalciferol (25(OH)D) by the enzyme CYP27B1 1-α-hydroxylase in kidney and several extrarenal tissues including breast. Although the development of breast cancer has been linked to inadequate vitamin D status, the importance of bioactive vitamin D production within tumors themselves is not fully understood. To investigate the role of tumoral vitamin D production in mammary epithelial cell progression to breast cancer, we conducted a Cre-loxP-mediated Cyp27b1 gene ablation in the mammary epithelium of the polyoma middle T antigen-mouse mammary tumor virus (PyMT-MMTV) mouse breast cancer model. Targeted ablation of Cyp27b1 was accompanied by significant acceleration in initiation of spontaneous mammary tumorigenesis. In vivo, cell proliferation, angiogenesis, cell cycle progression, and survival markers were up-regulated in tumors by Cyp27b1 ablation, and apoptosis was decreased. AK thymoma (AKT) phosphorylation and expression of several components of nuclear factor κB (NF-κB), integrin, and signal transducer and activator of transcription 3 (STAT3) signaling pathways were increased in Cyp27b1-ablated tumors compared with nonablated controls. In vitro, 1,25(OH)2D treatment induced a strong antiproliferative action on tumor cells from both ablated and nonablated mice, accompanied by rapid disappearance of NF-κB p65 from the nucleus and segregation in the cytoplasm. In contrast, treatment with the metabolic precursor 25(OH)D was only effective against cells from nonablated mice. 25(OH)D did not inhibit growth of Cyp27b1-ablated cells, and their nuclear NF-κB p65 remained abundant. Our findings demonstrate that in-tumor CYP27B1 1-α-hydroxylase activity plays a crucial role in controlling early oncogene-mediated mammary carcinogenesis events, at least in part by modulating tumoral cell NF-κB p65 nuclear translocation.
Department of Medicine (J.L., A.-L.L., B.O., I.F., A.C., R.K.), McGill University Health Centre and Goodman Cancer Research Centre (W.M.), McGill University, Montréal, Québec, Canada H3A 1A1; United States Department of Agriculture (Agricultural Research Service) National Animal Disease Center (T.A.R.), Ames, Iowa 50010; and Genetics Unit (R.S.-A.), Shriners Hospital for Children, Montréal, Québec, Canada H3G 1A6.
Jiarong
J
Li
Department of Medicine (J.L., A.-L.L., B.O., I.F., A.C., R.K.), McGill University Health Centre and Goodman Cancer Research Centre (W.M.), McGill University, Montréal, Québec, Canada H3A 1A1; United States Department of Agriculture (Agricultural Research Service) National Animal Disease Center (T.A.R.), Ames, Iowa 50010; and Genetics Unit (R.S.-A.), Shriners Hospital for Children, Montréal, Québec, Canada H3G 1A6.
Aimée-Lee
AL
Luco
Department of Medicine (J.L., A.-L.L., B.O., I.F., A.C., R.K.), McGill University Health Centre and Goodman Cancer Research Centre (W.M.), McGill University, Montréal, Québec, Canada H3A 1A1; United States Department of Agriculture (Agricultural Research Service) National Animal Disease Center (T.A.R.), Ames, Iowa 50010; and Genetics Unit (R.S.-A.), Shriners Hospital for Children, Montréal, Québec, Canada H3G 1A6.
Benoît
B
Ochietti
Department of Medicine (J.L., A.-L.L., B.O., I.F., A.C., R.K.), McGill University Health Centre and Goodman Cancer Research Centre (W.M.), McGill University, Montréal, Québec, Canada H3A 1A1; United States Department of Agriculture (Agricultural Research Service) National Animal Disease Center (T.A.R.), Ames, Iowa 50010; and Genetics Unit (R.S.-A.), Shriners Hospital for Children, Montréal, Québec, Canada H3G 1A6.
Ibtihal
I
Fadhil
Department of Medicine (J.L., A.-L.L., B.O., I.F., A.C., R.K.), McGill University Health Centre and Goodman Cancer Research Centre (W.M.), McGill University, Montréal, Québec, Canada H3A 1A1; United States Department of Agriculture (Agricultural Research Service) National Animal Disease Center (T.A.R.), Ames, Iowa 50010; and Genetics Unit (R.S.-A.), Shriners Hospital for Children, Montréal, Québec, Canada H3G 1A6.
Anne
A
Camirand
Department of Medicine (J.L., A.-L.L., B.O., I.F., A.C., R.K.), McGill University Health Centre and Goodman Cancer Research Centre (W.M.), McGill University, Montréal, Québec, Canada H3A 1A1; United States Department of Agriculture (Agricultural Research Service) National Animal Disease Center (T.A.R.), Ames, Iowa 50010; and Genetics Unit (R.S.-A.), Shriners Hospital for Children, Montréal, Québec, Canada H3G 1A6.
Timothy A
TA
Reinhardt
Department of Medicine (J.L., A.-L.L., B.O., I.F., A.C., R.K.), McGill University Health Centre and Goodman Cancer Research Centre (W.M.), McGill University, Montréal, Québec, Canada H3A 1A1; United States Department of Agriculture (Agricultural Research Service) National Animal Disease Center (T.A.R.), Ames, Iowa 50010; and Genetics Unit (R.S.-A.), Shriners Hospital for Children, Montréal, Québec, Canada H3G 1A6.
René
R
St-Arnaud
Department of Medicine (J.L., A.-L.L., B.O., I.F., A.C., R.K.), McGill University Health Centre and Goodman Cancer Research Centre (W.M.), McGill University, Montréal, Québec, Canada H3A 1A1; United States Department of Agriculture (Agricultural Research Service) National Animal Disease Center (T.A.R.), Ames, Iowa 50010; and Genetics Unit (R.S.-A.), Shriners Hospital for Children, Montréal, Québec, Canada H3G 1A6.
William
W
Muller
Department of Medicine (J.L., A.-L.L., B.O., I.F., A.C., R.K.), McGill University Health Centre and Goodman Cancer Research Centre (W.M.), McGill University, Montréal, Québec, Canada H3A 1A1; United States Department of Agriculture (Agricultural Research Service) National Animal Disease Center (T.A.R.), Ames, Iowa 50010; and Genetics Unit (R.S.-A.), Shriners Hospital for Children, Montréal, Québec, Canada H3G 1A6.
Richard
R
Kremer
D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D002112:Calcifediol / Q000096:biosynthesis / Q000097:blood; D002117:Calcitriol / Q000096:biosynthesis / Q000097:blood; D002118:Calcium / Q000097:blood; D049109:Cell Proliferation / Q000235:genetics / Q000502:physiology; D018450:Disease Progression; D005260:Female; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008297:Male; D015674:Mammary Neoplasms, Animal / Q000097:blood / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D016328:NF-kappa B / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014407:Tumor Cells, Cultured; D014807:Vitamin D / Q000096:biosynthesis* / Q000097:blood
D016328:NF-kappa B; D014807:Vitamin D; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D002117:Calcitriol; D002112:Calcifediol; D002118:Calcium