Tissue-engineered 3D cancer-in-bone modeling: silk and PUR protocols

Abstract

Cancers that metastasize or grow in the bone marrow are typically considered incurable and cause extensive damage to the bone and bone marrow. The bone is a complex, dynamic, three-dimensional (3D) environment composed of a plethora of cells that may contribute to, or constrain, the growth of tumor cells and development of bone disease. The development of safe and effective drugs is currently hampered by pre-clinical two-dimensional (2D) models whose poor predictive power does not accurately predict the success or failure of therapeutics. These inadequate models often result in drugs proceeding through extensive pre-clinical studies only to fail clinically. Consistently, 3D co-culture systems prove superior to 2D mono-cultures in modeling cell phenotypes, disease progression and response to therapeutics. As a complex, multicellular, multidimensional bone microenvironment, 3D models allow for more accurate predictions of tumor growth, cell-cell and cell-matrix interactions, and resulting therapeutic responses. In this review we will discuss various 3D models available and describe step-by-step protocols for two of the most well-established 3D culture models for studying tumor-induced bone disease.

Animal models for bone tissue engineering and modelling disease

“…While TE techniques can be applied in vitro to study the interaction between bone cells and cancer cells, only in vivo models are capable of recapitulating metastatic spread through the host vasculature and subsequent homing to the bone ( Dadwal et al, 2016 ; Hutmacher et al, 2010 ; Sitarski et al, 2018 ). Therefore, to understand the importance of the interaction between human bone and human cancer cells in modelling disease pathophysiology, several groups established rudimentary in vivo models of a humanised bone environment.…”

In vitro tissue-engineered adipose constructs for modeling disease

“…As researchers learn more about the contributions of obesity and adipose tissue to cancer progression, tissueengineered adipose models are becoming increasingly useful and necessary to interrogate the interactions between cancer cells and adipose tissues. (For more on 3D tissue-engineered in vitro models of cancer in bone, please see previous reviews [5,151].) In designing 3D adipose-cancer models, researchers must consider parameters such as: cell type/source, concentration, and ratios; scaffold material properties and pore size; media composition; imaging modalities desired; and potential bioreactor or other influences of stress or strain on the model.…”

3D Tissue Engineered in Vitro Models of Cancer in Bone

“…12,27 They also provide a comparatively high inter-fiber distance or pore size, compared to hydrogels, which facilitates nutrient and gas exchange as well as cell infiltration, which supports long-term culture. 12,28 These properties make sponges useful for cancer cell culture. Silk sponges have been shown to induce significantly different angiogenic factor expression in osteosarcoma models versus 2D cell culture.…”

“…For HA hydrogels the compressive modulus can range from 9.3kPa-22.6kPa. 28 Narayanan et al 22 tested matrix composition and stiffness of 3D, HA-based hydrogels for applications in BM MSCs and myeloma cell cultures. The percent survival of cells grown on medium stiffness hydrogels was higher than lower or higher stiffness samples, but cell viability was the same across all stiffness levels.…”