Zebrafish model of KRAS-initiated pancreatic endocrine tumor

Abstract

Pancreatic cancer constitutes a genetic disease in which somatic mutations in the KRAS proto-oncogene are detected in 95% of cases. Activation of the KRAS proto-oncogene represents an initiating event in pancreatic tumorigenesis. Here, we established a zebrafish pancreatic neoplasia model that recapitulates human pancreatic tumors. Toward this end, we generated a stable CRE/Lox-based zebrafish model system to express oncogenic KRAS G12D in the elastase3I domain of the zebrafish pancreas. Lineage tracing experiments showed that early KRAS G12D -responsive pancreatic progenitors contribute to endocrine in addition to exocrine cells. In this system, 10% and 40% of zebrafish developed pancreatic tumors by 6 and 12 months, respectively. The histological profiles of these experimental tumors bore a striking resemblance to those of pancreatic endocrine tumors. Immunohistochemical analysis including the endocrine cell-specific marker confirmed the pancreatic tumor region as a characteristic endocrine tumor. Taken together, our zebrafish model data revealed that pancreatic endocrine tumors originate from early KRAS G12D -responsive pancreatic progenitor cells. These findings demonstrated that this zebrafish model may be suitable as an experimental and preclinical system to evaluate different strategies for targeting pancreatic endocrine tumors and ultimately improve the outcome for patients with pancreatic endocrine tumors.

Pre-clinical Models of Metastasis in Pancreatic Cancer

“…The Protein Kinase, DNA-Activated, Catalytic Subunit (prkdc) and Interleukin 2 receptor (il2rga) deficient zebrafish model can be raised at 37°C and can engraft a wide range of human malignancies ( Yan et al, 2019 ). CRE/LOX technology and GAL4/UAS systems were combined to create the first kras-initiated PDAC model in zebrafish that highly recapitulates human PanIN development ( Oh and Park, 2019 ). A xenograft model was established in zebrafish by transplanting human pancreatic cancer cells into the perivitelline cavity of 48 h post-fertilization zebrafish embryos ( Guo et al, 2015 ).…”

Using Zebrafish as a Disease Model to Study Fibrotic Disease

“…The zebrafish pancreas develops and functions to secrete hormones for energy homeostasis in the early embryo stage (≤48 hpf). Human pancreasrelated diseases have been mimicked in zebrafish, namely chronic pancreatitis [22], cystic fibrosis [95], diabetes [96], and pancreatic cancer [14,97].…”

“…Contrary to Hh transgenic fish, oncogenic KRAS G12D expression in the elastase3I domain resulted ultimately in pancreatic endocrine tumours [14]. This expression can be placed under the control of the zebrafish ubb promoter by using the construct Tg(ubb-Lox-Nucleus-mCherry-Lox-GFP-KRAS G12D ).…”

“…As a matter of fact, 70% of protein-coding human genes are related to genes found in zebrafish, and 82% of the genes known to be associated with human diseases have a zebrafish counterpart. To the best of our knowledge, an estimated percentage in fibrosis-related pathways or genes has not been reported, although some relevant pathways (such as TGFβ/Activin signalling pathway [11], MAPK/ERK signalling [12]) and genes (such as tgf-β1, [13] 2, and 3 [11,13], KRAS G12D [14], vinmentin [11]) of fibrogenesis are active and expressed respectively in zebrafish. In addition, zebrafish have an immune system that is largely conserved with humans, with all different immune cell types present.…”

Genetic Engineering of Zebrafish in Cancer Research

“…Indeed, when an effector line expressing Cre under the control of the ela3l (elastase 3l) promoter was mated to a Tg(ubb:loxP-mCherry-loxP-GFP-KRAS G12V ) transgenic line, mCherry was excised from the target transgene and GFP-KRAS G12V expressed in the endocrine pancreas. As a result, 40% of the double-transgenic zebrafish develop pancreatic endocrine tumors by the age of 12 months [ 176 ].…”