The function of breast cancer resistance protein in epithelial barriers, stem cells and milk secretion of drugs and xenotoxins

2006 ◽  
Vol 27 (1) ◽  
pp. 10-16 ◽  
Author(s):  
Antonius E. van Herwaarden ◽  
Alfred H. Schinkel
Keyword(s):  
Breast Cancer ◽  
Stem Cells ◽  
Breast Cancer Resistance Protein ◽  
Milk Secretion ◽  
Cancer Resistance ◽  
Resistance Protein ◽  
Epithelial Barriers

scholarly journals Multidrug Transporter ABCG2/Breast Cancer Resistance Protein Secretes Riboflavin (Vitamin B2) into Milk

2006 ◽  
Vol 27 (4) ◽  
pp. 1247-1253 ◽  
Author(s):  
Antonius E. van Herwaarden ◽  
Els Wagenaar ◽  
Gracia Merino ◽  
Johan W. Jonker ◽  
Hilde Rosing ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Breast Cancer Resistance Protein ◽  
The Body ◽  
Systemic Availability ◽  
Vitamin B ◽  
Multidrug Transporter ◽  
Milk Secretion ◽  
Cancer Resistance ◽  
Riboflavin Deficiency ◽  
Resistance Protein

ABSTRACT The multidrug transporter breast cancer resistance protein (BCRP/ABCG2) is strongly induced in the mammary gland during pregnancy and lactation. We here demonstrate that BCRP is responsible for pumping riboflavin (vitamin B2) into milk, thus supplying the young with this important nutrient. In Bcrp1 −/− mice, milk secretion of riboflavin was reduced >60-fold compared to that in wild-type mice. Yet, under laboratory conditions, Bcrp1 −/− pups showed no riboflavin deficiency due to concomitant milk secretion of its cofactor flavin adenine dinucleotide, which was not affected. Thus, two independent secretion mechanisms supply vitamin B2 equivalents to milk. BCRP is the first active riboflavin efflux transporter identified in mammals and the first transporter shown to concentrate a vitamin into milk. BCRP activity elsewhere in the body protects against xenotoxins by reducing their absorption and mediating their excretion. Indeed, Bcrp1 activity increased excretion of riboflavin into the intestine and decreased its systemic availability in adult mice. Surprisingly, the paradoxical dual utilization of BCRP as a xenotoxin and a riboflavin pump is evolutionarily conserved among mammals as diverse as mice and humans. This study establishes the principle that an ABC transporter can transport a vitamin into milk and raises the possibility that other vitamins and nutrients are likewise secreted into milk by ABC transporters.

scholarly journals Breast Cancer Resistance Protein–Mediated Efflux of Androgen in Putative Benign and Malignant Prostate Stem Cells

2005 ◽  
Vol 65 (15) ◽  
pp. 6640-6650 ◽  
Author(s):  
Wendy J. Huss ◽  
Danny R. Gray ◽  
Norman M. Greenberg ◽  
James L. Mohler ◽  
Gary J. Smith
Keyword(s):  
Breast Cancer ◽  
Stem Cells ◽  
Breast Cancer Resistance Protein ◽  
Cancer Resistance ◽  
Resistance Protein ◽  
Malignant Prostate

The Breast Cancer Resistance Protein (BCRP/ABCG2) Affects Pharmacokinetics, Hepatobiliary Excretion, and Milk Secretion of the Antibiotic Nitrofurantoin

2005 ◽  
Vol 67 (5) ◽  
pp. 1758-1764 ◽  
Author(s):  
Gracia Merino ◽  
Johan W. Jonker ◽  
Els Wagenaar ◽  
Antonius E. van Herwaarden ◽  
Alfred H. Schinkel
Keyword(s):  
Breast Cancer ◽  
Breast Cancer Resistance Protein ◽  
Milk Secretion ◽  
Cancer Resistance ◽  
Resistance Protein
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