Organotypic slice cultures of pancreatic ductal adenocarcinoma as preclinical model for development of personalized treatment strategies

Introduction The prognosis of ductal adenocarcinomas of the pancreas (PDAC) is exceedingly poor and these tumors are notably resistant to conventional (radio)chemotherapy. Realistic preclinical models of PDAC reflecting the individual intratumor heterogeneity are urgently needed to test therapy response ex vivo and facilitate personalized patient treatment. However, currently used models such as patient-derived cell lines and xenografts lack the specific tumor microenvironment and therefore allow only limited response prediction.

Aims Ex vivo cultures of fresh tumor specimens as organotypic slice cultures (OTSCs) are a close approximation of the tumor in situ. OTSCs comprise an intact multicellular tissue composition. We aimed to refine the technique of OTSCs for PDAC to test the respective response to drugs ex vivo in a multicellular environment.

Methods Tissue slices of 300µm thickness were generated using a vibratome. Slices were cultured at an air-liquid interface on PTFE membranes and treated with gemcitabine. Changes in cell differentiation and viability were monitored by resazurin reduction and histopathology.

Results Macroscopic morphology of OTSCs was not altered substantially during cultivation, but the size of the surface area decreased over time. At defined periods of cultivation, OTSCs were fixed for histopathological characterization. H&E stain showed that the overall structure of the tissue was preserved during cultivation. No substantial changes in the tumor-to-stroma ratios were detected during cultivation. We did not detect increased apoptosis for about 9 days, but during extended cultivation periods as measured by cleaved caspase 3 staining. OTSCs were treated with 100µM gemcitabine and overall viability was measured by resazurin viability assay every 24 hours. We observed substantial differences in response to treatment of distinct OTSCs.

Conclusions OTSCs provide a unique opportunity to test individual treatment response to specific drugs ex vivo timely after surgical resection within 10-12 days. Perspectively, OTSCs allow to identify individual transcriptomic and proteomic profiles associated with the respective response. We conclude that OTSCs are a precious ex vivo tool for personalized treatment of PDAC.

Publication History

Article published online:
07 September 2021