The link between obesity and pancreatic cancer progression
Cancer spread, metastasis, accounts for >90% of cancer-related death. A major risk factor for the development of metastatic cancer is obesity. 10-15% of cancer-related deaths can now be traced back to an obese state. As the obesity epidemic intensifies, understanding the connection between obesity and cancer is a critical health issue and knowledge of how cancer cells adapt to the obese state is necessary to develop effective therapeutics for both obese and non-obese patients.
Pancreatic ductal adenocarcinoma (PDA) is the most deadly of major cancers and patients are in desperate need of improved therapies. PDA is promoted by chronic inflammatory stress associated with the increasingly common afflictions of obesity, type 2 diabetes, and pancreatitis, exacerbated by smoking and alcohol. Kras is an early driver of PDA, and oncogenic mutations (such as KrasG12D) are found in more than 90% of human PDA specimens. Unfortunately, Kras targeted drugs are not available despite decades of effort.
Here, we aim to determine the impact of obesity and PDA growth and spread. One critical component to this is being able to monitor tumor growth and spread in the correct microenvironment (containing the right components of the immune system and fibroblasts etc) e.g. primary growth in the pancreas and spread to the liver. In addition, we will test the tumorigenic effects of obesity-induced changes in the gut microbiota.
As mentioned above, one major connection between obesity and PDA is the role of obesity-induced inflammation. To include this parameter in our studies, we will adhere to syngeneic models in wild-type C57BL6 mice. Following tumor growth and spread, the tumors/metastatic nodules will be analyzed by a number of systems tools including mass cytometry and RNA/ATACseq. Syngeneic cell lines used here are derived from mutant Kras (G12D) and TP53null transgenic tumors as well as cells derived from Smad4 driven tumors. For these studies, we will use a total of 216 mice.
Studying metastatic spread in animals carries an inherent risk of causing pain. We will, therefore, adhere to stringent analgesia protocol and tumor monitoring (described below) to best possible limit such pain.
Principles of the three R’s.
Replacement: The aims of this study are to characterize the consequence of obesity on PDA progression. Tumor progression is a complex process, encompassing events such as invasive growth, angiogenesis, interaction with immune cells and other members of the microenvironment. The use of traditional in vitro assays do not recapitulate all of these processes. In this regard, mouse xenograft models represent an appropriate system to study tumor progression. Reduction: The combined experience from our and other collaborators over the past 8 years have found that the minimum number of animals required to detect significant biological meaningful differences in tumor growth using the bioluminescence/calipers are 6 mice per cohort. We will strictly adhere to this, to ensure no overuse of mice. We also include tumors of both sexes, so to maximize the use of breeding offspring. Refinement: The group has extensive experience in performing tumor implantation procedures, which ensure fast and reliable injections that inflict as little pain as possible for the mice.
Pancreatic ductal adenocarcinoma (PDA) is the most deadly of major cancers and patients are in desperate need of improved therapies. PDA is promoted by chronic inflammatory stress associated with the increasingly common afflictions of obesity, type 2 diabetes, and pancreatitis, exacerbated by smoking and alcohol. Kras is an early driver of PDA, and oncogenic mutations (such as KrasG12D) are found in more than 90% of human PDA specimens. Unfortunately, Kras targeted drugs are not available despite decades of effort.
Here, we aim to determine the impact of obesity and PDA growth and spread. One critical component to this is being able to monitor tumor growth and spread in the correct microenvironment (containing the right components of the immune system and fibroblasts etc) e.g. primary growth in the pancreas and spread to the liver. In addition, we will test the tumorigenic effects of obesity-induced changes in the gut microbiota.
As mentioned above, one major connection between obesity and PDA is the role of obesity-induced inflammation. To include this parameter in our studies, we will adhere to syngeneic models in wild-type C57BL6 mice. Following tumor growth and spread, the tumors/metastatic nodules will be analyzed by a number of systems tools including mass cytometry and RNA/ATACseq. Syngeneic cell lines used here are derived from mutant Kras (G12D) and TP53null transgenic tumors as well as cells derived from Smad4 driven tumors. For these studies, we will use a total of 216 mice.
Studying metastatic spread in animals carries an inherent risk of causing pain. We will, therefore, adhere to stringent analgesia protocol and tumor monitoring (described below) to best possible limit such pain.
Principles of the three R’s.
Replacement: The aims of this study are to characterize the consequence of obesity on PDA progression. Tumor progression is a complex process, encompassing events such as invasive growth, angiogenesis, interaction with immune cells and other members of the microenvironment. The use of traditional in vitro assays do not recapitulate all of these processes. In this regard, mouse xenograft models represent an appropriate system to study tumor progression. Reduction: The combined experience from our and other collaborators over the past 8 years have found that the minimum number of animals required to detect significant biological meaningful differences in tumor growth using the bioluminescence/calipers are 6 mice per cohort. We will strictly adhere to this, to ensure no overuse of mice. We also include tumors of both sexes, so to maximize the use of breeding offspring. Refinement: The group has extensive experience in performing tumor implantation procedures, which ensure fast and reliable injections that inflict as little pain as possible for the mice.