Development of a bioprinting approach for automated manufacturing of multi-cell type biocomposite TRACER strips using contact capillary-wicking.

In many types of solid cancer, interactions between tumour cells and their surrounding microenvironment significantly impact disease progression, and patient prognosis. Tissue engineered models permit investigations of cellular behaviour and interactions in the context of this diseased microenvironment. Previously our group developed the tissue roll for analysis of cellular environment and response (TRACER) platform.

A three-dimensional engineered heterogeneous tumor model for assessing cellular environment and response.

This protocol describes how to build and implement a three-dimensional (3D) cell culture system, TRACER (tissue roll for analysis of cellular environment and response), that enables analysis of cellular behavior and phenotype in hypoxic gradients. TRACER consists of infiltrating cells encapsulated in a hydrogel extracellular matrix (ECM) within a thin strip of porous cellulose scaffolding that is then rolled around an oxygen-impermeable mandrel for assembly of thick and layered 3D tissue constructs that develop cell-defined oxygen gradients. TRACER differs from other stacked-paper cell culture models because it is assembled from a single-piece scaffold, which facilitates rapid disassembly for analysis of different cell populations and metabolites.

A TRACER 3D Co-Culture tumour model for head and neck cancer.

Cancer-associated fibroblasts (CAFs) are a key component of the tumour microenvironment and have been shown to play an important role in the progression of cancer. To probe these tumour-stroma interactions, we incorporated CAFs derived from head and neck cancer patients and squamous carcinoma cells of the hypopharynx (FaDu) into the Tissue Roll for the Analysis of Cellular Environment and Response (TRACER) platform to establish a co-culture platform that simulates the CAF-tumour microenvironmental interactions in head and neck tumours. TRACER culture involves infiltrating cells into a thin fibrous scaffold and then rolling the resulting biocomposite around a mandrel to generate a 3D and layered structure.

The Current Landscape of 3D In Vitro Tumor Models: What Cancer Hallmarks Are Accessible for Drug Discovery?

Cancer prognosis remains a lottery dependent on cancer type, disease stage at diagnosis, and personal genetics. While investment in research is at an all-time high, new drugs are more likely to fail in clinical trials today than in the 1970s. In this review, a summary of current survival statistics in North America is provided, followed by an overview of the modern drug discovery process, classes of models used throughout different stages, and challenges associated with drug development efficiency are highlighted.

Development of TRACER: tissue roll for analysis of cellular environment and response.

The tumour microenvironment is heterogeneous and consists of multiple cell types, variable extracellular matrix (ECM) composition, and contains cell-defined gradients of small molecules, oxygen, nutrients and waste. Emerging in vitro cell culture systems that attempt to replicate these features often fail to incorporate design strategies to facilitate efficient data collection and stratification. The tissue roll for analysis of cellular environment and response (TRACER) is a novel strategy to assemble layered, three-dimensional tumours with cell-defined, graded heterogeneous microenvironments that also facilitates cellular separation and stratification of data from different cell populations from specific microenvironments.

Patterning cellular compartments within TRACER cultures using sacrificial gelatin printing.

In the past decade, it has been well recognised that the tumour microenvironment contains microenvironmental components such as hypoxia that significantly influence tumour cell behaviours such, invasiveness and therapy resistance, all of which provide new targets for studying cancer biology and developing anticancer therapeutics. In response, a large number of two-dimensional and three-dimensional (3D) in vitro tumour models have been developed to recapitulate different aspects of the tumour microenvironment and enable the study of related biological questions. While more complex models enable new biological insight, such models often involve time-consuming and complex fabrication or analysis processes, which limit their adoption by the broader cancer biology community.

A three-dimensional engineered tumour for spatial snapshot analysis of cell metabolism and phenotype in hypoxic gradients.

The profound metabolic reprogramming that occurs in cancer cells has been investigated primarily in two-dimensional cell cultures, which fail to recapitulate spatial aspects of cell-to-cell interactions as well as tissue gradients present in three-dimensional tumours. Here, we describe an engineered model to assemble three-dimensional tumours by rolling a scaffold-tumour composite strip. By unrolling the strip, the model can be rapidly disassembled for snapshot analysis, allowing spatial mapping of cell metabolism in concert with cell phenotype.