Spatial Engineering of Mammary Epithelial Cell Cultures with 3D Bioprinting Reveals Growth Control by Branch Point Proximity

Sep 21, 2026

Uploaded by Finn

The 3D structure of the ductal epithelium and the surrounding extracellular matrix (ECM) is crucial for mammary gland development, function, and malignancy, yet current in vitro models poorly reproduce branched epithelial architectures. A 3D bioprinting protocol was developed to pattern normal and cancerous mammary epithelial cells into branched Y-shaped structures to examine positioning effects on proliferation and invasion. Normal cells formed continuous networks with organotypic features, while DCIS-like cancer cells showed aberrant basal polarization and impaired basement membrane formation. Quantification over time showed increased proliferation at branch tips versus the trunk, especially farther from the branch point, independent of TGFβ signaling, while TGFβ inhibition reduced invasion.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages15

Reading Time38 min

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Abstract

Introduction

Journal of Mammary Gland Biology and Neoplasia (2024) 29:5 [https://doi.org/10.1007/s1091](https://doi.org/10.1007/s1091) 1-024-09557-1 RESEARCH Spatial Engineering of Mammary Epithelial Cell Cultures with 3DBioprinting Reveals Growth Control by Branch Point Proximity Leena M. Koskinen1,2 · Lari Nieminen3 · Antti Arjonen3 · Camilo Guzmán4 · Markus Peurla1,2 · Emilia Peuhu1,2 Received: 19 December 2023 / Accepted: 20 February 2024 © The Author(s) 2024 Abstract The three-dimensional (3D) structure of the ductal epithelium and the surrounding extracellular matrix (ECM) are integral aspects of the breast tissue, and they have important roles during mammary gland development, function and malignancy. However, the architecture of the branched mammary epithelial network is poorly recapitulated in the current in vitro models. 3D bioprinting is an emerging approach to improve tissue-mimicry in cell culture. Here, we developed and optimized a protocol for 3D bioprinting of normal and cancerous mammary epithelial cells into a branched Y-shape to study the role of cell positioning in the regulation of cell proliferation and invasion. Non-cancerous cells formed continuous 3D cell networks with several organotypic features, whereas the ductal carcinoma in situ (DCIS)–like cancer cells exhibited aberrant basal polarization and defective formation of the basement membrane (BM) . Quantitative analysis overtime demonstrated that both normal and cancerous cells proliferate more at the branch tips compared to the trunk region of the 3D-bioprinted cultures, and particularly at the tip further away from the branch point. The location-specific rate of proliferation was independent of TGFβ signaling but invasion of the DCIS-like breast cancer cells was reduced upon the inhibition of TGFβ . Thus, our data demonstrate that the 3D-bioprinted cells can sense their position in the branched network of cells and proliferate at the tips, thus recapitulating this feature of mammary epithelial branching morphogenesis. In all, our results demonstrate the capacity of the developed 3D bioprinting method for quantitative analysis of the relationships between tissue structure and cell behavior in breast morphogenesis and cancer. Keywords 3D bioprinting · Branching · Mammary gland · Breast cancer · Ductal carcinoma in situ Introduction The mammary gland develops through branching morphogenesis when mammary epithelial ducts invade and branch out to form a tubular network through bifurcation of the terminal end buds (TEB) and lateral side-branching [1] . While the ductal outgrowth is induced by hormonal changes during puberty, further side-branching occurs in the adult gland during the reproductive cycles [2] . The entire ductal-lobular 􀀍 Emilia Peuhu [emilia.peuhu@utu.fi](emilia.peuhu@utu.fi) 1 Institute of Biomedicine, Cancer Laboratory FICAN West, University of Turku, Turku, Finland 2 Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland 3 Brinter Inc, Turku, Finland 4 Euro-BioImaging ERIC, Turku, Finland epithelial structure originating from the teat is surrounded by a basement membrane (BM), and embedded in connective and adipose tissue. The normal tissue organization and composition of the surrounding extracellular matrix (ECM) have been shown to regulate the development of the mammary epithelium, and to maintain tissue homeostasis [3–6] . However, the specific mechanisms that locally promote or inhibit cell proliferation, motility, and invasion in the growing tissue are not fully understood. Various coordinated growth factor and ECM regulatory signals from the local stroma and the epithelium itself have been reported to guide mammary epithelial branching [7– 10] . Yet, it is not known how the species-specific branching patterns are achieved in the mammary gland, and which homeostatic mechanisms limit excessive growth in the healthy mammary gland but are overcome in breast cancer. In ductal carc

FAQs

What problem does the study address in current in vitro models?

Current in vitro models poorly recapitulate the architecture of the branched mammary epithelial network, limiting how cell positioning effects can be studied.

How were the mammary epithelial cells organized for the experiments?

Cells were 3D bioprinted into a branched Y-shape, allowing branch-tip versus trunk positioning to be tested in normal and DCIS-like cancer contexts.

What did the quantitative analysis show about proliferation in the 3D-bioprinted cultures?

Both normal and cancerous cells proliferated more at the branch tips than in the trunk region, with the highest rates at tips farther from the branch point.

Sep 21, 2026

Uploaded by Finn