DEVELOPMENT OF A BIOMIMETIC BREAST CANCER TISSUE MODEL UTILIZING ELECTROSPUN CIRCULAR DUCT AND 3D PRINTED PLATFORM

Abstract

Breast cancer continues to be the most prevalent cancer affecting women worldwide, and studies have projected that breast cancer cases will increase by 40 %, accounting for about 1 million deaths by 2040. The increasing breast cancer prevalence creates a high demand for developing breast cancer drugs and targeted therapies for aggressive cancer types like triple-negative breast cancer (TNBC). Three-dimensional (3D) in vitro models are extensively utilized for validating the efficacy of breast cancer drugs; however, some of the existing 3D cell culture models fail to mimic the extracellular matrix and architecture present in vivo. In this study, we developed a 3D breast tissue model using non-tumorigenic breast cell line HMT-3522 S1, breast cancer cell line MCF-7, and triple-negative breast cancer cell line MDA-MB-231, cultured on electrospun polycaprolactone (PCL) ducts to mimic ductal carcinoma in situ, a type of breast cancer that develops within the milk ducts. Electrospun ducts were fabricated using 25% PCL dissolved in a 1:1 ratio of dimethylformamide (DMF) and tetrahydrofuran (THF) solution. The electrospun duct fiber characterization was conducted using a scanning electron microscope (SEM) and capillary flow porometer. The effect of varying electrospinning polymer flow rate on pore size diameter was evaluated. We assessed the optimum cell seeding density required to achieve maximum cell coverage in the electrospun ducts and assessed the impact of electrospun fiber surface modification using collagen type I on cell attachment and proliferation. Fiber characterization analysis indicated duct fiber thickness of 0.025 mm and pore diameter of 0.6 µm at maximum pore size distribution. Increasing the electrospinning flow rate of 25% PCL polymer solution from 0.5 mL/hr to 2 mL/hr reduced the fiber pore diameter of the electrospun ducts and led to the formation of beads. Furthermore, increasing the electrospinning polymer flow rate significantly reduced the growth rate of cells (p < 0.05). Electrospun ducts proved to be a suitable scaffold for cell attachment and proliferation for both cell lines. HMT-3522 S1 cells achieved duct cell coverage of 50%, and MDA-MB-231 cells achieved duct cell coverage of 64% within 10 days of cell culture on uncoated fibers. There was a significant difference in cell attachment and proliferation between MDA-MB-231 cells cultured on collagen type I coated ducts and control at 48 hours after cell seeding (p < 0.05). Furthermore, coating ducts with collagen type I increased cell coverage of ducts to 90% within 7 days of cell culture. F-actin stain of MDA-MB-231 and MCF-7 cells in the ducts indicated normal cell morphology. MCF-7 cells formed a monolayer in the ducts, evidenced by cell-to-cell junction immunofluorescence staining using β-catenin. The study provides a breast tissue model that mimics the ductal architecture of breast ducts with a porous membrane that enhances cells' interaction with the extracellular environment. The model has future potential applications for breast cancer drug screening.