Dynamic interaction between breast cancer cells and osteoblastic tissue: Comparison of Two‐ and Three‐dimensional cultures

Abstract

Breast cancer cell colonization of osteoblast monolayers grown in standard tissue culture (2D) is compared to colonization of a multi-cell-layer osteoblastic tissue (3D) grown in a specialized bioreactor. Colonization of 3D tissue recapitulates events observed in clinical samples including cancer penetration of tissue, growth of microcolonies, and formation of "Single cell file" commonly observed in end-stage pathological bone tissue. By contrast, adherent cancer cell colonies did not penetrate 2D tissue and did not form cell files. Thus, it appears that 3D tissue is a more biologically (clinically) relevant model than 2D monolayers in which to study cancer cell interactions with osteoblastic tissue. This direct comparison of 2D and 3D formats is implemented using MC3T3-E1 murine osteoblasts and MDA-MB-231 human metastatic breast cancer cells, or the metastasis-suppressed line, MDA-MB-231BRMS1, for comparison. When osteoblasts were co-cultured with metastatic cells, production of osteocalcin (a mineralization marker) decreased and secretion of the pro-inflammatory cytokine IL-6 increased in both 2D and 3D formats. Cancer cell penetration of the 3D tissue coincided with a changed osteoblast morphology from cuboidal to spindle-shaped, and with osteoblasts alignment parallel to the cancer cells. Metastasis-suppressed cells did not penetrate 3D tissue, did not cause a change in osteoblast morphology or align in rows. Moreover, they proliferated much less in the 3D culture than in the 2D culture in a manner similar to their growth in bone. In both systems, the cancer cells proliferated to a greater extent with immature osteoblasts compared to more mature osteoblasts.

In Vitro Mimics of Bone Remodeling and the Vicious Cycle of Cancer in Bone

“…Co-culture of osteoclasts with osteoblastic tissue results in resorption of mineralized tissue. Co-culture of metastatic breast cancer cells with osteoblastic tissue is more complex but also leads to destruction of mineralized tissue (Dhurjati et al, 2008;Krishnan et al, 2011). In particular, we have observed that breast cancer cells sequentially attach to osteoblastic tissue, proliferate, and form cell columns that penetrate the tissue over a 3 day co-culture interval in the absence of osteoclasts.…”

Breast Cancer Metastasis: Advances Through the Use of In Vitro Co-Culture Model Systems

“…They observed that important pathologic events such as cancer cells infiltrating the bone cells in single file and microtumour formation that are seen clinically were reproduced their in vitro system. They also observed that breast cancer cell colonization of the bone cells depended strongly on the maturity of the osteoblastic culture (Dhurjati, Krishnan et al 2008;Mastro and Vogler 2009;Krishnan, Shuman et al 2010). A novel approach to three dimensional co-culturing of cells was developed by researchers at the University of Wisconsin-Madison in Madison, Wisconsin.…”

Methods for Culturing Human Femur Tissue Explants to Study Breast Cancer Cell Colonization of the Metastatic Niche

“…Although widely used in vivo mouse models facilitate systemic studies of the metastatic process [12][13][14][15] , cell interactions within the skeleton are not readily accessible for observation and direct perturbation. Model systems for studying and culturing mouse bone tissues and mouse marrow cells provide better access and have yielded many insights regarding crosstalk and mechanisms underlying breast cancer cell metastasis of the murine skeleton [16][17][18][19][20][21][22] . However, studies have suggested that there may be species-specific patterns of osteotropism for bone tissue 23,24 .…”

“…Although 2-dimensional cell culture models have formed the mainstay of in vitro approaches for cancer research, it has long been recognized that cell behavior is fundamentally altered in monolayer culture systems 18,36,37 . This has led to the development of engineered microenvironments that mimic the complexity of 3-dimensional living tissues, including matrix-and scaffold-based models composed of natural materials such as collagen, or synthetic polymers seeded with specific cell types to create tissue-like microenvironments [36][37][38][39][40][41] .…”

“…This has led to the development of engineered microenvironments that mimic the complexity of 3-dimensional living tissues, including matrix-and scaffold-based models composed of natural materials such as collagen, or synthetic polymers seeded with specific cell types to create tissue-like microenvironments [36][37][38][39][40][41] . Engineered approaches have also included the use of bioreactor platforms to control and study the hormonal milieu of the microenvironment 18,19,[41][42][43] . Although biomimetic models and bioreactors provide many elements of a complex tissue microenvironment in a controlled setting, and have been successfully applied to advance the study of breast cancer metastasis to bone .…”