Organotypic slice cultures of pancreatic ductal adenocarcinoma preserve the tumor microenvironment and provide a platform for drug response

Background

/Objective: The conventional models currently used to evaluate various anti-tumor therapeutic agents are not sufficient for representing human pancreatic ductal adenocarcinoma (PDA), which has a unique tumor microenvironment. We aimed to produce an organotypic slice culture model from human PDA that resembles the in vivo situation and to evaluate the responses of PDA slices to established cytotoxic drugs.

Methods

PDA tissues were obtained from 10 patients who underwent pancreatic resection. The tissues were sliced by a vibratome, and the tumor slices were then cultured. The viability of tumor slices during slice culture was evaluated using H&E and immunohistochemical staining, and stromal cells were demonstrated. The effects of cytotoxic drugs on PDA cell lines and slices were analyzed.

Results

Tumor slices maintained their surface areas and tissue viability for at least five days during culture. Preserved proliferation and apoptosis in tumor slices were observed by the expression of Ki-67 and cleaved caspase-3. Stromal cells including macrophages (CD68⁺ and CD163⁺), T cells (CD3⁺, CD8⁺, and FOXP3⁺), and myeloid cells (CD11b⁺) were present throughout the culture period. Staurosporine, gemcitabine, and cisplatin treatment of PDA cell lines and tumor slices exerted proportional cytotoxic effects in terms of MTT viability, tumor cell number, and Ki-67 and cleaved caspase-3 expression.

Conclusions

Organotypic human PDA slice cultures preserved their viability and tumor microenvironment for at least five days during slice culture. PDA slice culture appears to be a feasible preclinical test model to assess the response to anti-tumor agents.