Adipocyte differentiation influences the proliferation and migration of normal and tumoral breast epithelial cells

Abstract

Abstract. Stromal tissue regulates the development and differentiation of breast epithelial cells, with adipocytes being the main stromal cell type. The aim of the present study was to evaluate the effect of adipocyte differentiation on proliferation and migration, as well as to assess the activity of heparanase and metalloproteinase-9 (MMP-9), in normal (nMuMG) and tumoral (lM3) murine breast epithelial cells. nMuMG and lM3 cells were grown on irradiated 3T3-l1 cells (stromal support, SS) at various degrees of differentiation [preadipocytes (prea), poorly differentiated adipocytes (pda) and mature adipocytes (Ma)] and/or were incubated in the presence of conditioned medium (cM) derived from each of these three types of differentiated cells. cells grown on a plastic support or in fresh medium served as the controls. cell proliferation was measured with a commercial colorimetric kit, and the motility of the epithelial cells was evaluated by means of a wound-healing assay. Heparanase activity was assessed by quantifying heparin degradation, and the expression of MMP-9 was determined using Western blotting. The results indicate that cell proliferation was increased after 24 and 48 h in the nMuMG and lM3 cells grown on prea, pda and Ma SS. in the nMuMG cells cultured on SS in the presence of all three types of cM, proliferation was enhanced. lM3 cell migration was increased in the presence of all three types of cM and in cells grown on prea SS. Heparanase activity was increased in the nMuMG cells incubated with all three types of cM, and in the lM3 cells incubated with the cM from pda and Ma. Both the nMuMG and lM3 cell lines presented basal expression of MMP-9; however, a significant increase in MMP-9 expression was observed in the lM3 cells incubated with each of the three types of cM. in conclusion, adipocyte differentiation influences normal and tumoral breast epithelial cell proliferation and migration. Heparanase and MMP-9 appear to be involved in this regulation. The experimental model presented in this study is in keeping with the characteristics of the physiological environment of breast epithelial cells, in terms of both the soluble and insoluble factors present and the stromal structure per se.

Adipocyte/breast cancer cell crosstalk in obesity interferes with the anti-proliferative efficacy of tamoxifen

“…To highlight the influence of adipocyte secretome on Tx efficacy , we used conditioned media obtained from the culture of MA20 or MA30 (CM20 and CM30) and showed that CM30 raised MCF-7 and 184B5 proliferation compared to CM20 treatment. Similarly, the effects of adipocyte differentiation on proliferation and migration of normal (NMuMG) and tumoral (LM3) murine breast epithelial cells were increased with 3T3-L1 conditioned media [ 31 ]. In studies using human samples, the incubation of normal (MCF10a) and malignant (MCF-10CA1) breast epithelial cells with breast adipocyte conditioned media (Adip-CM) increased cell motility [ 32 ].…”

Interfering Role of ERα on Adiponectin Action in Breast Cancer

“…Fletcher et al demonstrated profound changes in the proteomic profile between the conditioned media obtained from human adipose tissue explants of breast tumors (hATT-CMs) compared to human adipose tissue explants of normal breast tissue (hATN-CMs). Most of the proteins differentially expressed were involved in important biological processes, including immune response and metabolism, and the treatment with hATT-CMs induces proliferation, adhesion and migration of breast cancer cells (41)(42)(43). In obese condition, adipocytes are hypertrophic, due to the increased accumulation of intracellular triglyceride stores caused by the energy imbalance, and hyperplastic, since their number augments in this pathology (44).…”

Stromal-Epithelial Interactions during Mammary Gland Development

“…In vitro studies on normal human MECs (NMuMG cell line) elegantly demonstrated the effect of signaling molecules secreted by adipocytes. NMuMG cells were incubated for 24 or 48 h in the presence of conditioned medium derived from adipocytes (3T3-L1 cell line) at various degrees of differentiation: preadipocytes (preA), poorly differentiated adipocytes (pDA), and mature adipocytes (MA) [23]. After 24 h treatment human MECs showed significantly increased proliferative activity when cultured in conditioned media from pDA and MA, whereas after 48 h incubation the effect of increase proliferation was observed in the case of all conditioned media (preA, pDA, and MA) [23].…”

“…NMuMG cells were incubated for 24 or 48 h in the presence of conditioned medium derived from adipocytes (3T3-L1 cell line) at various degrees of differentiation: preadipocytes (preA), poorly differentiated adipocytes (pDA), and mature adipocytes (MA) [23]. After 24 h treatment human MECs showed significantly increased proliferative activity when cultured in conditioned media from pDA and MA, whereas after 48 h incubation the effect of increase proliferation was observed in the case of all conditioned media (preA, pDA, and MA) [23]. Another study revealed that 24 h treatment with conditioned medium from mature adipocytes induced branching morphogenesis of mammary tubules, with sites localized to the ends of the tubules, without appreciable lumen formation, which indicates that the biologically active molecules produced by adipocytes influence mostly the ductal growth [20].…”