Modelling and Validating Three-Dimensional Human Breast and Cancerous Human Breast Tissues In Vitro

In this study three dimensional (3-D) in vitro models of normal breast and breast cancer tissues were developed to mimic closely the in vivo tissue microenvironment and therefore providing reliable models for in vitro studies as well as testing of novel cancer therapies. Normal and cancerous human breast cell lines were used to construct 3-D artificial tissues, where de-epidermalised dermis (DED) was used as a scaffold for both models. Morphological analyses were conducted using haematoxylin and eosin staining. Biomarkers including keratin 5 and 19 as well as α smooth muscle actin and mucin 1 were used to confirm and validate the reliability of the proposed models using immunohistochemical techniques. Findings suggest that the 3-D in vitro models described in this work can serve as functional models of both human normal and cancerous breast tissues. Multiple structures similar to ducts and lobules of human breast in vivo were observed in 3-D in vitro models by the use of H&E, some breast cancer colonies seen in the cancerous 3-D model were similar to the ducto-lobular structures observed in normal 3-D model of the breast but the former cells were more loosely connected, irregular and largely disorganized. The established 3-D in vitro model of normal breast showed the development of ducto-lobular structures composed of an inner cell layer which was stained positive with α mucin 1 antibody, a biomarker that is characteristic for luminal cells; and also an outer basal layer of cells that was stained positive for α smooth muscle actin, a biomarker of myoepithelial cells.. Keratin staining in 3-D in vitro models also resembled the pattern observed in vivo where keratin 5 was detected in both luminal and myoepithelial cells of normal breast model (NTERT cells), whereas keratin 19 was present in breast cancer model (C2321 cells). These 3-D models successfully recapitulate both normal and pathological tissue architecture of breast tissue and has the potential for various applications in the evaluation of breast cancer progression and treatment.