Intraperitoneal dissemination of ovarian cancers is preceded by the development of chemoresistant tumors with malignant ascites. Despite the high levels of chemoresistance and relapse observed in ovarian cancers, there are no
in vitro
models to understand the development of chemoresistance
in situ
.
Method:
We describe a highly integrated approach to establish an
in vitro
model of chemoresistance and stemness in ovarian cancer, using the 3D hanging drop spheroid platform. The model was established by serially passaging non-adherent spheroids. At each passage, the effectiveness of the model was evaluated
via
measures of proliferation, response to treatment with cisplatin and a novel ALDH1A inhibitor. Concomitantly, the expression and tumor initiating capacity of cancer stem-like cells (CSCs) was analyzed. RNA-seq was used to establish gene signatures associated with the evolution of tumorigenicity, and chemoresistance. Lastly, a mathematical model was developed to predict the emergence of CSCs during serial passaging of ovarian cancer spheroids.
Results:
Our serial passage model demonstrated increased cellular proliferation, enriched CSCs, and emergence of a platinum resistant phenotype.
In vivo
tumor xenograft assays indicated that later passage spheroids were significantly more tumorigenic with higher CSCs, compared to early passage spheroids. RNA-seq revealed several gene signatures supporting the emergence of CSCs, chemoresistance, and malignant phenotypes, with links to poor clinical prognosis. Our mathematical model predicted the emergence of CSC populations within serially passaged spheroids, concurring with experimentally observed data.
Conclusion:
Our integrated approach illustrates the utility of the serial passage spheroid model for examining the emergence and development of chemoresistance in ovarian cancer in a controllable and reproducible format.
Over the past 3 decades, there has
been a vast expansion of research
in both tissue engineering and organic electronics. Although the two
fields have interacted little, the materials and fabrication technologies
which have accompanied the rise of organic electronics offer the potential
for innovation and translation if appropriately adapted to pattern
biological materials for tissue engineering. In this work, we use
two organic electronic materials as adhesion points on a biocompatible
poly(p-xylylene) surface. The organic electronic
materials are precisely deposited via vacuum thermal
evaporation and organic vapor jet printing, the proven, scalable processes
used in the manufacture of organic electronic devices. The small molecular-weight
organics prevent the subsequent growth of antifouling polyethylene
glycol methacrylate polymer brushes that grow within the interstices
between the molecular patches, rendering these background areas both
protein and cell resistant. Last, fibronectin attaches to the molecular
patches, allowing for the selective adhesion of fibroblasts. The process
is simple, reproducible, and promotes a high yield of cell attachment
to the targeted sites, demonstrating that biocompatible organic small-molecule
materials can pattern cells at the microscale, utilizing techniques
widely used in electronic device fabrication.
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