Accumulation of multipotent progenitors with a basal differentiation bias during aging of human mammary epithelia

TY - JOUR

T1 - Accumulation of multipotent progenitors with a basal differentiation bias during aging of human mammary epithelia

AU - Garbe, James C

AU - Pepin, Francois

AU - Pelissier, Fanny A

AU - Sputova, Klara

AU - Fridriksdottir, Agla J

AU - Guo, Diana E

AU - Villadsen, Rene

AU - Park, Morag

AU - Petersen, Ole W

AU - Borowsky, Alexander D

AU - Stampfer, Martha R

AU - Labarge, Mark A

PY - 2012/7/15

Y1 - 2012/7/15

N2 - Women older than 50 years account for 75% of new breast cancer diagnoses, and the majority of these tumors are of a luminal subtype. Although age-associated changes, including endocrine profiles and alterations within the breast microenvironment, increase cancer risk, an understanding of the cellular and molecular mechanisms that underlies these observations is lacking. In this study, we generated a large collection of normal human mammary epithelial cell strains from women ages 16 to 91 years, derived from primary tissues, to investigate the molecular changes that occur in aging breast cells. We found that in finite lifespan cultured and uncultured epithelial cells, aging is associated with a reduction of myoepithelial cells and an increase in luminal cells that express keratin 14 and integrin-α6, a phenotype that is usually expressed exclusively in myoepithelial cells in women younger than 30 years. Changes to the luminal lineage resulted from age-dependent expansion of defective multipotent progenitors that gave rise to incompletely differentiated luminal or myoepithelial cells. The aging process therefore results in both a shift in the balance of luminal/myoepithelial lineages and to changes in the functional spectrum of multipotent progenitors, which together increase the potential for malignant transformation. Together, our findings provide a cellular basis to explain the observed vulnerability to breast cancer that increases with age.

AB - Women older than 50 years account for 75% of new breast cancer diagnoses, and the majority of these tumors are of a luminal subtype. Although age-associated changes, including endocrine profiles and alterations within the breast microenvironment, increase cancer risk, an understanding of the cellular and molecular mechanisms that underlies these observations is lacking. In this study, we generated a large collection of normal human mammary epithelial cell strains from women ages 16 to 91 years, derived from primary tissues, to investigate the molecular changes that occur in aging breast cells. We found that in finite lifespan cultured and uncultured epithelial cells, aging is associated with a reduction of myoepithelial cells and an increase in luminal cells that express keratin 14 and integrin-α6, a phenotype that is usually expressed exclusively in myoepithelial cells in women younger than 30 years. Changes to the luminal lineage resulted from age-dependent expansion of defective multipotent progenitors that gave rise to incompletely differentiated luminal or myoepithelial cells. The aging process therefore results in both a shift in the balance of luminal/myoepithelial lineages and to changes in the functional spectrum of multipotent progenitors, which together increase the potential for malignant transformation. Together, our findings provide a cellular basis to explain the observed vulnerability to breast cancer that increases with age.

KW - Aged

KW - Aged, 80 and over

KW - Aging

KW - Cell Aging

KW - Cell Differentiation

KW - Cells, Cultured

KW - Epithelial Cells

KW - Female

KW - Humans

KW - Mammary Glands, Human

KW - Middle Aged

KW - Multipotent Stem Cells

KW - Phenotype

U2 - 10.1158/0008-5472.CAN-12-0157

DO - 10.1158/0008-5472.CAN-12-0157

M3 - Journal article

C2 - 22552289

SN - 1538-7445

VL - 72

SP - 3687

EP - 3701

JO - Cancer Research

JF - Cancer Research

IS - 14

ER -