iTRAQ Quantitative Proteomic Profiling and MALDI–MSI of Colon Cancer Spheroids Treated with Combination Chemotherapies in a 3D Printed Fluidic Device

For
a patient with metastatic colorectal cancer there are limited
clinical options aside from chemotherapy. Unfortunately, the development
of new chemotherapeutics is a long and costly process. New methods
are needed to identify promising drug candidates earlier in the drug
development process. Most chemotherapies are administered to patients
in combinations. Here, an in vitro platform is used to assess the
penetration and metabolism of combination chemotherapies in three-dimensional
colon cancer cell cultures, or spheroids. Colon carcinoma HCT 116
cells were cultured and grown into three-dimensional cell culture
spheroids. These spheroids were then dosed with a common combination
chemotherapy, FOLFIRI (folinic acid, 5-fluorouracil, and irinotecan)
in a 3D printed fluidic device. This fluidic device allows for the
dynamic treatment of spheroids across a semipermeable membrane. Following
dosing, the spheroids were harvested for quantitative proteomic profiling
to examine the effects of the combination chemotherapy on the colon
cancer cells. Spheroids were also imaged to assess the spatial distribution
of administered chemotherapeutics and metabolites with MALDI–imaging
mass spectrometry. Following treatment, we observed penetration of
folinic acid to the core of spheroids and metabolism of the drug in
the outer proliferating region of the spheroid. Proteomic changes
identified included an enrichment of several cancer-associated pathways.
This innovative dosing device, along with the proteomic evaluation
with iTRAQ-MS/MS, provides a robust platform that could have a transformative
impact on the preclinical evaluation of drug candidates. This system
is a high-throughput and cost-effective approach to examine novel
drugs and drug combinations prior to animal testing.