Clinical applications of 3D normal and breast cancer organoids: A review of concepts and methods

Abstract

While mouse models and two-dimensional (2D) cell culture systems have dominated as research tools for cancer biology, three-dimensional (3D) cultures have gained traction as a new approach that retains features of in vivo biology within an in vitro system. Over time, 3D culture systems have evolved from spheroids and tumorspheres to organoids, and by doing so, they have become more complex and representative of original tissue. Such technological improvements have mostly benefited the study of heterogeneous solid tumors, like those found in breast cancer (BC), by providing an attractive avenue for scalable drug testing and biobank generation. Experimentally, organoids have been used in the BC field to dissect mechanisms related to cellular invasion and metastasis-and through co-culture methods-epithelial interactions with stromal and immune cells. In addition, organoid studies of wild-type mouse models and healthy donor samples have provided insight into the basic developmental cellular and molecular biology of the mammary gland, which may inform one's understanding of the initial stages of cancer development and progression.

Keywords: Breast cancer; extracellular matrix; high-throughput drug testing; mammary gland development; organoids; personalized medicine.

Figure 1.

Transwell migration assay with normal Brca1 KO (knockout) murine mammary organoids. (A) Overall scheme to test migratory properties of organoid cultures. Mammary-derived organoid cultures can either be dissociated into single cells or plated as whole organoids, into transwell chambers. (B) Normal Brca1 KO mammary-derived organoid cultures, either bearing 1 copy or total loss of the p53 gene, were tested for their mobility capacity in transwell chambers, indicating differential migratory capacity based on p53 genotype. Scale bar: 100 µm.