A rat model of pancreatic ductal adenocarcinoma: targeting chemical carcinogens
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J A Rivera1, F Graeme-Cook, J Werner
1Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA.
Background:
Current experimental models of pancreatic cancer either fail to reproduce the ductal phenotype or cause simultaneous cancers in other organs also. To develop an animal of pancreatic cancer that accurately mimics the human condition, we restricted carcinogenic exposure to the pancreas and specifically targeted ductal epithelial cells. Three different carcinogens were either implanted directly into the pancreas or infused into the pancreatic duct, with or without near-total pancreatectomy (as a means of inducing pancreatic ductal cell proliferation).
Methods:
Groups of male Sprague-Dawley rats were exposed to varying doses of dimethylbenzanthracine (DMBA), methynitronitrosoguanidine, or ethylnitronitrosoguanidine either through direct implantation into the pancreas or infusion into the pancreatic duct. Near-total pancreatectomy was added in all groups except two DMBA implantation groups. Surviving rats were killed at 3, 6, 9, or 12 months, and the pancreata were evaluated histologically.
Results:
All three carcinogens caused pancreatic inflammation, ductal hyperplasia, atypia, and dysplasia beginning by 3 months and becoming more prominent at later time points. Only DMBA caused frequent invasive pancreatic ductal adenocarcinoma, which was first evident by 6 months. The prevalence of pancreatic cancer among DMBA-treated rats evaluated after 10 months was 39% (19 of 49). The addition of pancreatic resection did not enhance pancreatic cancer development.
Conclusions:
Of the strategies tested, only direct implantation of DMBA into the rat pancreas frequently produces pancreatic cancer histologically similar to human ductal adenocarcinoma. The development of hyperplastic, atypical, and dysplastic changes preceding and accompanying carcinomas suggests that these lesions are preneoplastic. This model recapitulates the progression from normal to neoplastic epithelium and is likely to be useful for the study of morphologic and molecular mechanisms underlying the early stages of pancreatic carcinogenesis and for the investigation of novel diagnostic and therapeutic techniques.
Insights
Developing a new rat model for pancreatic cancer using dimethylbenzanthracine (DMBA) successfully created tumors similar to human ductal adenocarcinoma. This model aids in studying pancreatic cancer development and testing new therapies.
Area of Science:
- Oncology
- Animal Models
- Gastroenterology
Background:
- Existing pancreatic cancer models do not accurately replicate human ductal adenocarcinoma or affect other organs.
- Developing a precise animal model is crucial for understanding pancreatic cancer progression.
Purpose of the Study:
- To create an accurate animal model for pancreatic ductal adenocarcinoma.
- To investigate carcinogenic effects specifically on pancreatic ductal epithelial cells.
Main Methods:
- Male Sprague-Dawley rats were exposed to carcinogens (DMBA, methynitronitrosoguanidine, ethylnitronitrosoguanidine) via pancreatic implantation or ductal infusion.
- Near-total pancreatectomy was performed in some groups to stimulate ductal cell proliferation.
- Rats were analyzed histologically at 3, 6, 9, and 12 months.
Main Results:
- All carcinogens induced pancreatic inflammation and preneoplastic changes (hyperplasia, atypia, dysplasia).
- Dimethylbenzanthracine (DMBA) frequently caused invasive pancreatic ductal adenocarcinoma, evident by 6 months.
- DMBA treatment resulted in a 39% prevalence of pancreatic cancer after 10 months; pancreatectomy did not increase cancer incidence.
Conclusions:
- Direct pancreatic implantation of DMBA in rats is an effective method for generating pancreatic cancer models resembling human ductal adenocarcinoma.
- Observed hyperplastic, atypical, and dysplastic changes indicate preneoplastic lesions preceding carcinoma development.
- This model accurately reflects the progression from normal to neoplastic epithelium, valuable for studying early pancreatic carcinogenesis and developing diagnostics/therapeutics.