The establishment of organotypic preclinical models that
accurately
resemble the native tumor microenvironment at an anatomic human scale
is highly desirable to level up in vitro platforms
potential for screening candidate therapies. The bioengineering of
anatomic-scaled three-dimensional (3D) models that emulate native
tumor scale while recapitulating their cellular and matrix components
remains, however, to be fully realized. In this focus, herein, we
leveraged embedded 3D bioprinting for biofabricating pancreatic ductal
adenocarcinoma (PDAC) in vitro models combining gelatin-methacryloyl
and hyaluronic acid methacrylate extracellular matrix (ECM)-mimetic
biomaterials with human pancreatic cancer cells and cancer-associated
fibroblasts to generate in vitro models capable of
emulating native tumor size (∼6 mm) and stromal elements. By
using a viscoelastic continuous polymeric supporting bath, tumor-scale
3D models were rapidly generated (∼50 constructs/h) and easily
recovered following in-bath visible light photocrosslinking. As a
proof-of-concept, tissue-scale constructs displaying physiomimetic
designs were biofabricated. These models also encompass the incorporation
of a stromal compartment to better emulate the cellular components
of the PDAC native tumor microenvironment (TME) and its stratified
spatial organization. Cell-laden tumor-size constructs remained viable
for up to 14 days and were responsive to Gemcitabine in a dose-dependent
mode. Cancer-stroma models also exhibited increased drug resistance
compared to their monotypic counterparts, highlighting the key role
of stromal cells in chemotherapeutic resistance. Overall, we report
for the first time the freeform biofabrication of PDAC models exhibiting
anatomic scale, different structural complexities, and engineered
cancer-stromal compartments, being highly valuable for preclinical
screening of therapeutics.