Project description:Several aspects of a Western lifestyle such as increased obesity and decreased physical activity are associated with increased risk for gastrointestinal cancers1. Although high-fat diet (HFD) induced low-grade inflammation has been closely linked to tumorigenesis2, however, the microbial shift that occurs due to diet and consequent alterations in host immunity have merely been considered to play a critical role during carcinogenesis. Here we show that HFD promotes tumor progression in the small intestine of genetically susceptible mice, however, independently of obesity and diet-induced chronic inflammation. HFD consumption cooperates with mutant K-Ras to mediate a shift in the composition of microbiota, which is associated with a decrease in Paneth cell antimicrobial host defense that compromises dendritic cell (DC) recruitment and MHCII presentation in the gut-associated lymphoid tissues (GALTs). DC recruitment in GALTs can be normalized and tumor progression attenuated completely when K-Ras mutant mice are supplemented with the short chain fatty acid butyrate, a bacterial fermentation end product, or partially when provided with probiotics. Importantly, Myd88-deficiency completely blocks tumor progression in K-ras mutants, however, rather by substantial changes in the microbiota than host-mediated signaling mechanisms. Strikingly, transfer of fecal samples from diseased donors into healthy adult K-ras mutants is sufficient to enhance tumor progression in the absence of HFD suggesting a pivotal role for distinct microbiota shifts in aggravating disease in the small intestine. Collectively, these data underscore the reciprocal interaction between host and environmental factors for the composition of intestinal microbiota that favors carcinogenesis and suggest tumor progression could potentially be “transmitted” in genetically predisposed individuals.
Project description:Several aspects of a Western lifestyle such as increased obesity and decreased physical activity are associated with increased risk for gastrointestinal cancers1. Although high-fat diet (HFD) induced low-grade inflammation has been closely linked to tumorigenesis2, however, the microbial shift that occurs due to diet and consequent alterations in host immunity have merely been considered to play a critical role during carcinogenesis. Here we show that HFD promotes tumor progression in the small intestine of genetically susceptible mice, however, independently of obesity and diet-induced chronic inflammation. HFD consumption cooperates with mutant K-Ras to mediate a shift in the composition of microbiota, which is associated with a decrease in Paneth cell antimicrobial host defense that compromises dendritic cell (DC) recruitment and MHCII presentation in the gut-associated lymphoid tissues (GALTs). DC recruitment in GALTs can be normalized and tumor progression attenuated completely when K-Ras mutant mice are supplemented with the short chain fatty acid butyrate, a bacterial fermentation end product, or partially when provided with probiotics. Importantly, Myd88-deficiency completely blocks tumor progression in K-ras mutants, however, rather by substantial changes in the microbiota than host-mediated signaling mechanisms. Strikingly, transfer of fecal samples from diseased donors into healthy adult K-ras mutants is sufficient to enhance tumor progression in the absence of HFD suggesting a pivotal role for distinct microbiota shifts in aggravating disease in the small intestine. Collectively, these data underscore the reciprocal interaction between host and environmental factors for the composition of intestinal microbiota that favors carcinogenesis and suggest tumor progression could potentially be “transmitted” in genetically predisposed individuals. 13 samples; S103_396_GroupA_Arkan and S104_429_GroupA_Arkan represent the controls of the first group, S105_394_GroupB_Arkan and S106_429_GroupB_Arkan represent ViRas (mutated) mice of the first group. S982_groupA_ 1 and S983_groupA_2 represent the cotrols of the second group, S984_groupB_3, S985_groupB_4 and S986_groupB_5 represent ViRas (mutant) mice of the second group, S563_CO1979 represent the control of the third group, S564_KO1_1231, S565_KO2_1984 and S566_KO3_2013 represent the ViRas (mutant) mice of the third group. The first group are mice kept on HFD, second group kept on ND and third group kept on HFD plus treated with butyrate
Project description:Younger age and obesity increase the incidence and rates of metastasis of triple-negative breast cancer (TNBC), an aggressive subtype of breast cancer. The tissue microenvironment, specifically the extracellular matrix (ECM), is known to promote tumor invasion and metastasis. We sought to characterize the effect of both age and obesity on the ECM of mammary fat pads. We used a diet-induced obesity (DIO) model where 10-week-old female mice were fed a high-fat diet (HFD) for 16 weeks or a control chow diet (CD) where time points were every 4 weeks to monitor age and obesity HFD progression. We isolated the mammary fat pads to characterize the ECM at each time point. Utilizing proteomics, we found that the early stages of obesity were sufficient to induce distinct differences in the ECM composition of mammary fat pads that promote TNBC cell invasion. ECM proteins previously implicated in driving TNBC invasion Collagen IV and Collagen VI, were enriched with weight gain. Together these data implicate ECM changes in the primary tumor microenvironment as mechanisms by which age and obesity contribute to breast cancer progression.
Project description:Background: Post-menopausal obesity is an established risk factor for breast cancer. Consumption of diets high in fat is known to be highly correlated with obesity. In this, we sought to evaluate the interaction(s) between high fat diet, weight gain and mammary carcinogenesis using an obese-resistant and obese-prone rat model with direct correlates to human disease. Methods: Female obese-prone (OP) and obese-resistant (OR) weanling rats were placed on either a low fat (10% kcal) or a high fat (39% kcal) n-6 polyunsaturated (PUFA) safflower diet for 30 days. At post natal day (PND) 50, global gene expression profiling was performed on microdissected mammary epithlelium from one cohort of rats and another cohort of rats were given a single oral gavage of either 7,12-dimethylbenz[a]anthracene (DMBA at 14 mg/kg) or vehicle. Rats were then maintained on the diets and body weights, food consumption and development of mammary lesions were monitored weekly. Results: The DMBA-treated OR rats on the 39% safflower diet had significantly greater incidence of ductal carcinoma-in-situ (DCIS) lesions and significantly greater DCIS multiplicity than DMBA-treated OR rats on the 10% safflower diet. These differences were not seen in the OP strain. Gene expression analysis of mammary ductal epithelium from OR rats on the high fat diet showed significant upregulation of proliferation-related genes compared to those consuming the low fat safflower diet. Again, these differences were not seen in the OP strain. Conclusion: Our findings indicate that consumption of high fat safflower diet enhances mammary carcinogenesis in an OR rat strain through increased proliferation of mammary epithelium at the time of exposure, but not in the OP rat strain. Thus, the diet-induced increase in sensitivity was strain-specific and independent of weight gain or obesity level. Female obese-prone (OP) and obese-resistant (OR) weanling rats were placed on either a low fat (10% kcal) or a high fat (39% kcal) n-6 polyunsaturated (PUFA) safflower diet for 30 days. At post natal day (PND) 50, global gene expression profiling was performed on microdissected mammary epithlelium from one cohort of rats and another cohort of rats were given a single oral gavage of either 7,12-dimethylbenz[a]anthracene (DMBA at 14 mg/kg) or vehicle. Rats were then maintained on the diets and body weights, food consumption and development of mammary lesions were monitored weekly.
Project description:Background: Post-menopausal obesity is an established risk factor for breast cancer. Consumption of diets high in fat is known to be highly correlated with obesity. In this, we sought to evaluate the interaction(s) between high fat diet, weight gain and mammary carcinogenesis using an obese-resistant and obese-prone rat model with direct correlates to human disease. Methods: Female obese-prone (OP) and obese-resistant (OR) weanling rats were placed on either a low fat (10% kcal) or a high fat (39% kcal) n-6 polyunsaturated (PUFA) safflower diet for 30 days. At post natal day (PND) 50, global gene expression profiling was performed on microdissected mammary epithlelium from one cohort of rats and another cohort of rats were given a single oral gavage of either 7,12-dimethylbenz[a]anthracene (DMBA at 14 mg/kg) or vehicle. Rats were then maintained on the diets and body weights, food consumption and development of mammary lesions were monitored weekly. Results: The DMBA-treated OR rats on the 39% safflower diet had significantly greater incidence of ductal carcinoma-in-situ (DCIS) lesions and significantly greater DCIS multiplicity than DMBA-treated OR rats on the 10% safflower diet. These differences were not seen in the OP strain. Gene expression analysis of mammary ductal epithelium from OR rats on the high fat diet showed significant upregulation of proliferation-related genes compared to those consuming the low fat safflower diet. Again, these differences were not seen in the OP strain. Conclusion: Our findings indicate that consumption of high fat safflower diet enhances mammary carcinogenesis in an OR rat strain through increased proliferation of mammary epithelium at the time of exposure, but not in the OP rat strain. Thus, the diet-induced increase in sensitivity was strain-specific and independent of weight gain or obesity level.
Project description:The aim of this study was to investigate the causative effect of CS induced dysbiosis on obesity and insulin resistance in a high-fat diet induced obese (DIO) mouse model. Male germ-free BALB/c mice were humanized by fecal microbiota transfer using samples from children born by CS or VD and fed HFD for 16 weeks. Adipose tissue was sampled for RNAseq at study termination.
Project description:Obesity is a major cancer risk factor, but the underlying molecular mechanisms are not always known. In this study, we look at proteome remodeling in cancer cells with obesity, comparing tumor cells sorted from mice fed high-fat versus control diet. We conducted 10-plex TMT-proteomics on GFP+ MC38 colorectal adenocarcinoma tumor cells, sorted from subcutaneously implanted tumors 12 days after implantation. This study reveals molecular pathways that change in cancer cells with obesity that promote tumor growth.