Low concentrations of transforming growth factor-beta-1 induce tubulogenesis in cultured mammary epithelial cells

Abstract

Background: Formation of branching tubes is a fundamental step in the development of glandular organs. To identify extracellular cues that orchestrate epithelial tubulogenesis, we employed an in vitro assay in which EpH4-J3B1A mammary epithelial cells form spheroidal cysts when grown in collagen gels under serum-free conditions, but form branching tubules in the presence of fetal calf serum (FCS).

Curvature-dependent constraints drive remodeling of epithelia

“…J3B1A cells show slightly larger dimensions and have a more squamous cell aspect (Soulié et al, 2014). They usually form spheroidal cysts as well, but exhibit branching tubules in the presence of low concentrations of transforming growth factor beta (Montesano et al, 2007).…”

Mammary branch initiation and extension are inhibited by separate pathways downstream of TGFβ in culture

“…Knockdown of p38α disrupts branching of cultured embryonic lungs [69] and treatment with the pharmacological inhibitor SB203580 blocks growth of cultured embryonic kidneys [70] and tubulogenesis of collecting duct epithelial cells [71, 72]. One group has also reported that TGFβ induces branching morphogenesis of mammary epithelial cells in culture through p38 MAPK [73]; it is important to note that the concentrations of TGFβ used in that study (100-500 pg/ml) are 5-25-fold higher than those used here, and in our hands lead to massive apoptosis of mammary epithelial cells under all culture conditions tested (data not shown). Whether p38 MAPK plays a role in the inhibition of mammary branching by TGFβ in vivo will require further testing and the generation of targeted deletions or conditional mutants.…”

How Little Is Too Much? How Transient Tumor-Stromal Crosstalk Can Control Tumor Progression

“…Indeed, TGF-β has been described as a tubulogen in a 3D model of mammary tubulogenesis, where TGF-β concentrations of 20 pg/ml to 100 pg/ml induce mammary tubulogenesis in vitro [11]. However, tubulogenesis is increasingly disturbed if TGF-β concentrations are greater than 200 pg/ml [11].…”

“…Indeed, TGF-β has been described as a tubulogen in a 3D model of mammary tubulogenesis, where TGF-β concentrations of 20 pg/ml to 100 pg/ml induce mammary tubulogenesis in vitro [11]. However, tubulogenesis is increasingly disturbed if TGF-β concentrations are greater than 200 pg/ml [11]. At 200–500 pg/ml TGF-β pointed outgrowths that lack a visible lumen are observed, and concentrations greater than 500 pg/ml lead to disorganized, lumen-less cell aggregates from which streaks of cells grow into the surrounding matrix.…”