3D organoid models allow detailed study of pancreas tumorigenesis

Last Updated: 2015-01-02

By Will Boggs MD

NEW YORK (Reuters Health) - Newly developed 3-dimensional organoid models of human and mouse ductal pancreatic cancer will allow scientists to elucidate details of its pathogenesis and, someday, develop personalized treatments for these deadly malignancies.

"Pancreatic organoid cultures are readily prepared from surgical resections and endoscopic biopsies of normal and neoplastic pancreatic tissues," Dr. David A. Tuveson from Cold Spring Harbor Laboratory in Cold Spring Harbor, New York, told Reuters Health by email. "These pancreatic organoids can be analyzed for genetic mutations to identify personalized therapeutic approaches (besides the oncogenic Kras mutant)."

Earlier cellular models of pancreatic cancer were developed in 2-dimensional culture conditions that do not support the growth of untransformed, nonneoplastic cells, and previous 3-dimensional strategies of normal, untransformed cells only allowed minimal propagation.

Dr. Tuveson and colleagues modified approaches previously pioneered to culture intestinal, gastric, colon carcinoma, hepatic, pancreatic, and prostatic organoids to generate normal and neoplastic pancreatic organoids and used the resulting 3-dimensional human and murine pancreatic tissues to investigate the pathogenesis and progression of pancreatic ductal adenocarcinoma.

These organoids survived cryopreservation and exhibited ductal- and disease-stage-specific characteristics of pancreatic adenocarcinoma, and orthotopically transplanted neoplastic organoids recapitulated the full spectrum of tumor development in mice.

Gene expression analysis of murine pancreatic organoids identified 772 downregulated and 863 upregulated genes in preneoplastic organoids relative to normal pancreatic organoids, nearly 3000 down- and upregulated genes in neoplastic organoids, and 823 downregulated and 640 upregulated genes in neoplastic organoids relative to preneoplastic organoids.

Similarly, there were 710 protein isoform expression changes between normal and preneoplastic organoids, 1047 changes between normal and neoplastic organoids, and 63 differentially expressed proteins between preneoplastic and neoplastic organoids, according to the December 31 Cell online report.

When the investigators examined a subset of these genes and proteins in primary pancreatic tissue specimens, 13 of 14 showed increased expression in mouse preneoplastic and neoplastic lesions, and 7 of 11 were upregulated in human pancreatic ductal adenocarcinoma specimens.

"Currently, it takes several weeks to prepare pancreatic organoids from a tumor biopsy, and costs approximately 10,000 US dollars," Dr. Tuveson said. "Because the organoids can be prepared from endoscopic biopsies, sequential monitoring is possible for pancreatic cancer patients. For patients receiving systemic chemotherapy and radiotherapy, organoid production is compromised. Iterative improvements in culture conditions should shorten the time of propagation and decrease the costs."

His message to practicing physicians: don't assume that a pancreatic malignancy is "a typical Kras mutant tumor" that will be resistant to therapy. Instead, he says, "Pursue getting the tumor growing in an organoid culture so it can be sequenced and then subjected to therapeutic interrogation."

"Organoid technology is a new method of culturing human normal and neoplastic tissues, and it has the potential to revolutionize the care of pancreatic cancer patients," he said.

SOURCE: http://bit.ly/1BrBw3m

Cell 2014