Effects of matrix components on aromatase activity in breast stromal cells in culture

Mechanical phenotype is important for stromal aromatase expression

“…Despite extensive studies of intratumoral stromal aromatase expression, relatively little is known about dysregulation of aromatase expression and local estrogen production in cancer-free microenvironment. However, there is a substantial individual-based variation in stromal aromatase expression [5, 14, 15]. Furthermore, forced expression of aromatase in mouse mammary gland results in hyperplasia [16] and increased incidence of chemical-induced tumor growth [17], supporting the notion that prolonged exposure to aberrant local estrogen biosynthesis can promote breast cancer.…”

Endogenous aromatization of testosterone results in growth stimulation of the human MCF-7 breast cancer cell line

“…It is still elusive which cell types that are responsible for intratumoral estrogen production, as aromatase protein has been immunohistochemically detected in both epithelial breast cancer cells and surrounding tumor stromal cells [11][12][13][14][15]. Further, in vitro cell culture studies have shown aromatase activity in both epithelial breast cancer cell lines [16][17][18][19] and breast-derived stromal fibroblasts from normal breast tissue and breast tumors [20][21][22][23]. The basal aromatase activity in both cell types is low, but the activity in fibroblasts can be highly stimulated with factors as IL-6, PGE 2 , TNF␣ and dexamethasone [20][21][22][23].…”

“…Further, in vitro cell culture studies have shown aromatase activity in both epithelial breast cancer cell lines [16][17][18][19] and breast-derived stromal fibroblasts from normal breast tissue and breast tumors [20][21][22][23]. The basal aromatase activity in both cell types is low, but the activity in fibroblasts can be highly stimulated with factors as IL-6, PGE 2 , TNF␣ and dexamethasone [20][21][22][23]. Only a moderate stimulation of aromatase enzyme activity has been reported in epithelial breast cancer cells [18,19].…”

Translational studies on aromatase, cyclooxygenases, and enzyme inhibitors in breast cancer

“…Aromatase activity has also been demonstrated in breast tissue in vitro [3][4][5][6], and the importance of intratumoral aromatase and local estrogen production is being unraveled [4,[7][8][9]. Aromatase has been measured in the stromal cell component of normal breast and breast tumors, but the enzyme has also been detected in the breast epithelial cells in vitro [3,[7][8][9][10][11]. Furthermore, expression of aromatase is highest in or near breast tumor sites [9].…”