A novel experimental model for human mixed acinar–ductal pancreatic cancer

Abstract

Pancreatic cancer has remained refractory to treatment. In large part, this results from the lack of an animal model that mimics pancreatic cancer in man. We describe a novel experimental model of pancreatic cancer that shares the genetic background, histologic features and natural history of human mixed acinar–ductal carcinoma. Adult wild-type mice received an injection into the pancreatic duct of lentivirus coding two molecules, KrasG12D mutation and shRNA p53, which recapitulate the mechanisms of pancreatic cancer in humans. The lentivirus constructs also co-expressed the luciferase gene for in vivo imaging by bioluminescence using the Xenogen IVIS imaging system. Weeks post-injection wild-type mice develop pancreatic cancer with the same histologic characteristics and metastases observed with human pancreatic mixed acinar–ductal carcinoma. This novel approach represents the first pancreatic cancer model that does not involve alterations of embryonic development, which is inherent with transgenic mice or knockout mice models. This novel experimental human pancreatic cancer model can be used to more effectively test new anti-cancer drug to inhibit tumor progression in situ and to retard metastases. Furthermore, our method of injecting lentivirus containing oncogenes and molecules implicated in the development of pancreatic can be employed in diabetic and obese mice, two common metabolic conditions characterized by an increased incidence of pancreatic cancer.

In vivo multiplex gene targeting with Streptococcus pyogens and Campylobacter jejuni Cas9 for pancreatic cancer modeling in wild-type animal

“…AAV-SpCas9, AAV-sgRNAs) did not develop pancreatic cancer, but group 2 (B6-SpCas9, AAV-sgRNAs) and group 3 (FVB, AAV-CjCas9-sgRNAs) mice developed early stage of PanIN. Cancer lesion seemed to be detectable after 6 months of AAV-CRISPR transduction, and this is similar to previous reports [29].…”

“…Even mutation of each candidate genes enrolled in specific PanIN stage, we tried to develop simultaneous multiplex gene mutation for avoiding multiple surgery for AAV transduction. AAV-SpCas9 and AAV-CjCas9 developed PanIN, but there is no evidence of metastasis and overall progression is slower than previous in vivo pancreatic cancer modeling [17,29]. The reason for the slow PanIN development is still uncertain, but the transduction with lower AAV particles number than other studies and the low frequency of Kras G12D would cause this.…”

“…The reason for the slow PanIN development is still uncertain, but the transduction with lower AAV particles number than other studies and the low frequency of Kras G12D would cause this. In addition, the influence of transduction route on slow PanIN development could not be confirmed, whether common bile duct or direct pancreatic injection, but unexpectedly, ductal injection developed slower and early grade PanIN than direct pancreatic injection [15,17,29]. However, there were several findings such as 1) multiple DSB potential of AAV-CjCas9, 2) peri-ductal lymphocyte infiltration in every groups, 3) multi-focal cancer marker expression with AAV mediated gene editing, and 4) need more than 12 months for developing initiation of PanIN in AAV mediated targeting.…”

“…SpCas9 has simple PAM (5′-NGG-3′) and develops a relatively higher DSB frequency than other CRISPR orthologues that have been previously reported for in vivo cancer modeling utilizing SpCas9 orthologues [12,15,16,17,29]. In this study, we also applied SpCas9 for DSB formation for the selected targets.…”

Animal Models

“…129 In Swiss Webster mice, intraductal infusion of lentivirus has been used to drive expression of shRNAp53, Kras G12D and luciferase. 130 These mice develop pathology similar to human PDAC without requiring alterations of embryonic development. They develop PanINs with increasing severity followed by tumor formation 28 weeks post-virus injection.…”