posted on 2021-10-18, 16:05authored byJacqueline Kort-Mascort, Guangyu Bao, Osama Elkashty, Salvador Flores-Torres, Jose G. Munguia-Lopez, Tao Jiang, Allen J. Ehrlicher, Luc Mongeau, Simon D. Tran, Joseph M. Kinsella
Reinforced
extracellular matrix (ECM)-based hydrogels recapitulate
several mechanical and biochemical features found in the tumor microenvironment
(TME) in vivo. While these gels retain several critical structural
and bioactive molecules that promote cell–matrix interactivity,
their mechanical properties tend toward the viscous regime limiting
their ability to retain ordered structural characteristics when considered
as architectured scaffolds. To overcome this limitation characteristic
of pure ECM hydrogels, we present a composite material containing
alginate, a seaweed-derived polysaccharide, and gelatin, denatured
collagen, as rheological modifiers which impart mechanical integrity
to the biologically active decellularized ECM (dECM). After an optimization
process, the reinforced gel proposed is mechanically stable and bioprintable
and has a stiffness within the expected physiological values. Our
hydrogel’s elastic modulus has no significant difference when
compared to tumors induced in preclinical xenograft head and neck
squamous cell carcinoma (HNSCC) mouse models. The bioprinted cell-laden
model is highly reproducible and allows proliferation and reorganization
of HNSCC cells while maintaining cell viability above 90% for periods
of nearly 3 weeks. Cells encapsulated in our bioink produce spheroids
of at least 3000 μm2 of cross-sectional area by day
15 of culture and are positive for cytokeratin in immunofluorescence
quantification, a common marker of HNSCC model validation in 2D and
3D models. We use this in vitro model system to evaluate the standard-of-care
small molecule therapeutics used to treat HNSCC clinically and report
a 4-fold increase in the IC50 of cisplatin and an 80-fold
increase for 5-fluorouracil compared to monolayer cultures. Our work
suggests that fabricating in vitro models using reinforced dECM provides
a physiologically relevant system to evaluate malignant neoplastic
phenomena in vitro due to the physical and biological features replicated
from the source tissue microenvironment.