Establishment of Canine Transitional Cell Carcinoma Cell Lines Harboring BRAF V595E Mutation as a Therapeutic Target.

Transitional cell carcinoma (TCC) is the most common malignant tumor of the canine urinary tract and tends to have a poor prognosis due to its invasive potential. Recent studies have reported that up to 80% of canine urothelial carcinoma has the BRAF V595E mutation, which is homologous to the human V600E mutation. Activating the BRAF mutation is an actionable target for developing effective therapeutic agents inhibiting the BRAF/mitogen-activated protein kinase (MAPK) pathway in canine cancer as well as human cancer. We established novel canine TCC cell lines from two tumor tissues and one metastatic lymph node of canine TCC patients harboring the BRAF V595E mutation. Tumor tissues highly expressed the BRAF mutant and phosphorylated extracellular signal-related kinases (ERK)1/2 proteins. The derived cell lines demonstrated activated MAPK pathways. We also evaluated the cell lines for sensitivity to BRAF inhibitors. Sorafenib, a multiple kinase inhibitor targeting RAF/vascular endothelial growth factor receptor (VEGFR), successfully inhibited the BRAF/MAPK pathway and induced apoptosis. The established canine TCC cell lines responded with greater sensitivity to sorafenib than to vemurafenib, which is known as a specific BRAF inhibitor in human cancer. Our results demonstrated that canine TCC cells showed different responses compared to human cancer with the BRAF V600E mutation. These cell lines would be valuable research materials to develop therapeutic strategies for canine TCC patients.

12α-Hydroxylated bile acid induces hepatic steatosis with dysbiosis in rats.

There is an increasing need to explore the mechanism of the progression of non-alcoholic fatty liver disease. Steroid metabolism is closely linked to hepatic steatosis and steroids are excreted as bile acids (BAs). Here, we demonstrated that feeding WKAH/HkmSlc inbred rats a diet supplemented with cholic acid (CA) at 0.5 g/kg for 13 weeks induced simple steatosis without obesity. Liver triglyceride and cholesterol levels were increased accompanied by mild elevation of aminotransferase activities. There were no signs of inflammation, insulin resistance, oxidative stress, or fibrosis. CA supplementation increased levels of CA and taurocholic acid (TCA) in enterohepatic circulation and deoxycholic acid (DCA) levels in cecum with an increased ratio of 12α-hydroxylated BAs to non-12α-hydroxylated BAs. Analyses of hepatic gene expression revealed no apparent feedback control of BA and cholesterol biosynthesis. CA feeding induced dysbiosis in cecal microbiota with enrichment of DCA producers, which underlines the increased cecal DCA levels. The mechanism of steatosis was increased expression of Srebp1 (positive regulator of liver lipogenesis) through activation of the liver X receptor by increased oxysterols in the CA-fed rats, especially 4ß-hydroxycholesterol (4ßOH) formed by upregulated expression of hepatic Cyp3a2, responsible for 4ßOH formation. Multiple regression analyses identified portal TCA and cecal DCA as positive predictors for liver 4ßOH levels. The possible mechanisms linking these predictors and upregulated expression of Cyp3a2 are discussed. Overall, our observations highlight the role of 12α-hydroxylated BAs in triggering liver lipogenesis and allow us to explore the mechanisms of hepatic steatosis onset, focusing on cholesterol and BA metabolism.

Inhibitory Effect of Olive Leaf Extract on Obesity in High-fat Diet-induced Mice.

BACKGROUND/AIM: The rapid increase in the number of people who are overweight or obese, which increases the risk of diseases and health problems, is becoming an important issue. Herein, we investigated whether olive leaf extract (OLE) has potent anti-obesity effects in high-fat induced mouse models. MATERIALS AND METHODS: C57BL/6 mice were randomized into normal control, high-fat diet (HFD), HFD with OLE, and HFD with garcinia groups and administered experimental diets for 12 weeks. Body weight and food intake were measured once per week and obesity-related biomarkers were evaluated in the serum and adipose tissue. RESULTS: OLE significantly suppressed weight gain, food efficiency ratio, visceral fat accumulation, and serum lipid composition in HFD-induced mice. Furthermore, the expression of adipogenesis- and thermogenesis-related molecules was decreased in the OLE-treated group. CONCLUSION: OLE prevents obesity development by regulating the expression of molecules involved in adipogenesis and thermogenesis.

Chemopreventive and Chemotherapeutic Effects of Fish Oil derived Omega-3 Polyunsaturated Fatty Acids on Colon Carcinogenesis.

Colorectal cancer is the third most common cause of cancer related death in the world. Multiple lines of evidence suggest that there is an association between consumption of dietary fat and colon cancer risk. Not only the amount but also the type and the ratio of fatty acids comprising dietary fats consumed have been implicated in the etiology and pathogenesis of colon cancer. Omega-3 (n-3) polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), have been known to inhibit development of colon cancer by downregulating the expression of genes involved in colon carcinogenesis and also by altering the membrane lipid composition. Data from laboratory, epidemiological, and clinical studies substantiate the beneficial role of n-3 PUFAs in preventing colitis and subsequent development of colon cancer. In addition, recent studies suggest that some n-3 PUFAs can be effective as an adjuvant with chemotherapeutic agents and other natural anticancer compounds in the management of colon cancer. In this review, we discuss chemopreventive and therapeutic effects of fish oil derived long chain n-3 PUFAs, particularly EPA and DHA, with focus on synergetic effects of which they exert when combined with chemotherapeutic agents and other natural compounds.

Diet supplementation with cholic acid promotes intestinal epithelial proliferation in rats exposed to γ-radiation.

Consumption of a high-fat diet increases some secondary bile acids (BAs) such as deoxycholic acid (DCA) in feces. DCA is derived from cholic acid (CA), a primary BA. We evaluated intestinal epithelial proliferation and BA metabolism in response to oral administration of cholic acid (CA) in rats to determine the influence of a CA diet on the responses of gut epithelia to γ-rays. WKAH/HkmSlc rats were divided into two dietary groups: control diet or CA-supplemented (2g/kg diet) diet. Some of the rats from each group were irradiated with γ-rays, and epithelial cell proliferation in the colon was analyzed histochemically. Unirradiated CA-fed rats had high levels of DCA and CA in the sera, as well as the presence of taurocholic acid in their feces. Significant increases were observed in both epithelial proliferation and the number of epithelial cells in the colon of the CA-fed rats, and this effect was observed at 8 weeks after γ-ray exposure. Furthermore, extracts from both cecal contents and sera of the unirradiated CA-fed rats promoted proliferation of IEC-6 cells. These results indicate that BAs in enterohepatic circulation promote proliferation and survival of the intestinal epithelium after receiving DNA damage.