Development of a Biomimetic Breast Cancer Tissue Model Utilizing Electrospun Scaffolds and a Co-Culturing System

Abstract

Breast cancer is the most prevalent cancer among women worldwide, with studies projecting a 40% increase in incidence by 2040. Two-dimensional (2D) cell culture models have been widely in cancer research. However, these cancer models are often unreliable as they do not recapitulate the native 3D microenvironment, including critical cell-cell and cell-matrix interactions. This study presents a 3D breast cancer tissue model using human hormone-receptor positive breast cancer cell line (MCF-7) and triple-negative breast cancer cell line (MDA-MB-231), cultured on electrospun polycaprolactone (PCL) scaffolds to mimic ductal carcinoma in situ. PCL electrospun scaffolds were fabricated using a 1:1 ratio of dimethylformamide (DMF) and tetrahydrofuran (THF) solution. The electrospun fibers were then characterized using a scanning electron microscope for average fiber diameter measurement. The biological and mechanical properties of the electrospun scaffolds were optimized for cell culture to evaluate their ability to support cell proliferation. For this purpose, different concentrations of PCL ranging from 7 to 15 w/v% (7, 8, 10, 12.5, and 15) were tested. At low concentrations (7 and 8 w/v%), bead defects were observed in the fibers. Therefore, 10, 12.5, and 15 w/v% were selected to examine the effect of fiber diameter on cellular growth. The optimal cell seeding density required to achieve maximum cell coverage in the electrospun scaffolds was assessed for MCF-7 and MDA-MB-231 cells. It was found that a 15 w/v% PCL solution, with a 30-minute electrospinning duration, and 5x 106 cell/mL seeding density resulted in the highest cell coverage of 90% by day 4 of culture for both cell lines. Two scaffold types of 15w/v% concentration, duct and membrane, were fabricated, and cell growth was assessed from day 1 to day 4. MCF-7 cells grew better on the membrane than on the ductal model, with significant growth detected between days 1 and 3, and between days 1 and 4 on both scaffolds (p<0.05). MDA-MB-231 cells, known for their invasive nature, proliferated rapidly, reaching a 90% area coverage by day 4 of culture on the membrane and by day 7 on the duct. In addition, the effect of collagen type I coating on the duct was investigated with the aim to enhance MCF-7 proliferation. By day four of culture, MCF-7 cells exhibited a significant increase in cell proliferation in coated versus uncoated ducts (p<0.01). The electrospun scaffolds proved to be a suitable scaffold for cell attachment and proliferation for both cell lines. Normal breast cells (MCF10A) cells will be cultured on3 the scaffolds and then co-cultured with malignant breast cells (MCF-7 or MDA-MB- 231) to replicate the in vivo tumor complexity. The proposed 3D biomimetic co-culture tumor model is expected to closely resemble the in vivo representation of breast cancer compared to existing models, thus enabling more effective drug screening and advancing both basic and applied breast cancer research.