Sodium glucose cotransporter 2 inhibitors are expected to ameliorate the abnormalities associated with metabolic syndrome including non-alcoholic fatty liver disease. In this study, we investigated the effects of the sodium glucose cotransporter 2 inhibitor tofogliflozin on the development of non-alcoholic fatty liver disease-related liver tumorigenesis in C57BL/KsJ-+Leprdb/+Leprdb obese and diabetic mice. The direct effects of tofogliflozin on human liver cancer cell proliferation were also evaluated. Mice were administered diethylnitrosamine-containing water for 2 weeks and were treated with tofogliflozin throughout the experiment. In mice treated with tofogliflozin, the development of hepatic preneoplastic lesions was markedly suppressed, and hepatic steatosis and inflammation significantly reduced, as evaluated using the non-alcoholic fatty liver disease activity score, in comparison with the control mice. Serum levels of glucose and free fatty acid and mRNA expression levels of pro-inflammatory markers in the liver were reduced by tofogliflozin treatment. Conversely, the proliferation of sodium glucose cotransporter 2 protein-expressing liver cancer cells was not inhibited by this agent. These findings suggest that tofogliflozin suppressed the early phase of obesity- and non-alcoholic fatty liver disease-related hepatocarcinogenesis by attenuating chronic inflammation and hepatic steatosis. Therefore, sodium glucose cotransporter 2 inhibitors may have a chemopreventive effect on obesity-related hepatocellular carcinoma.

Obesity and its related metabolic abnormalities, including enhanced oxidative stress and chronic inflammation, are closely related to colorectal tumorigenesis. Pentoxifylline (PTX), a methylxanthine derivative, has been reported to suppress the production of tumor necrosis factor (TNF)-α and possess anti-inflammatory properties. The present study investigated the effects of PTX on the development of carcinogen-induced colorectal premalignant lesions in obese and diabetic mice. Male C57BL/KsJ-db/db mice, which are severely obese and diabetic, were administered weekly subcutaneous injections of the colonic carcinogen azoxymethane (15 mg/kg body weight) for four weeks and then received drinking water containing 125 or 500 ppm PTX for eight weeks. At the time of sacrifice, PTX administration markedly suppressed the development of premalignant lesions in the colorectum. The levels of oxidative stress markers were significantly decreased in the PTX-treated group compared with those in the untreated control group. In PTX-administered mice, the mRNA expression levels of cyclooxygenase (COX)-2, interleukin (IL)-6, and TNF-α, and the number of proliferating cell nuclear antigen (PCNA)-positive cells in the colonic mucosa, were significantly reduced. These observations suggest that PTX attenuated chronic inflammation and oxidative stress, and prevented the development of colonic tumorigenesis in an obesity-related colon cancer model.

Non-alcoholic fatty liver disease has become one of the most common causes of chronic liver disease that can develop into a more serious form, non-alcoholic steatohepatitis, leading to liver cirrhosis and hepatocellular carcinoma. Although hepatic retinoid stores are progressively lost during the development of liver disease, how this affects steatohepatitis and its related hepatocarcinogenesis is unknown. In order to investigate these, we used subcutaneous injection of streptozotocin (0.2 mg/body) and high-fat diet to induce steatohepatitis and hepatic tumorigenesis in lecithin:retinol acyltransferase -deficient mice (n = 10), which lack stored retinoid in the liver, and control mice (n = 12). At the termination of the experiment (16 weeks of age), the development of hepatic tumors was significantly suppressed in mutant mice compared to controls. Lower serum levels of alanine aminotransferase and decreased hepatic levels of cyclin D1 were observed in mutant mice. Mutant mice exhibited increased levels of retinoic acid-responsive genes, including p21, and decreased oxidative stress as evaluated by serum and liver markers. Our findings are consistent with the conclusion that mutant mice are less susceptible to steatohepatitis-related liver tumorigenesis due to increased retinoid signaling, which is accompanied by up-regulated p21 expression and attenuated oxidative stress.

Obesity, diabetes mellitus, and their related metabolic abnormalities are associated with increased risk of hepatocellular carcinoma (HCC). Anti-diabetic agents sodium glucose cotransporter (SGLT)-2 inhibitors are expected to ameliorate the abnormalities associated with metabolic syndrome including non-alcoholic fatty liver disease (NAFLD). In this study, we investigated the effects of the SGLT2 inhibitor tofogliflozin on the development of NAFLD-related liver tumorigenesis in C57BL/KsJ-+Leprdb/+Leprdb (db/db) obese and diabetic mice. The direct effects of tofogliflozin on human hepatoma cell lines were also evaluated. Male db/db mice were administered diethylnitrosamine-containing water for two weeks and were then treated with tofogliflozin throughout the experiment. Tofogliflozin was kindly provided by Kowa Co., Ltd. and the chemical structure will be disclosed at the time of presentation at the meeting. In mice treated with tofogliflozin, the development of hepatic pre-neoplastic lesions, foci of cellular alterations, was markedly suppressed, and hepatic steatosis and inflammation significantly reduced, as evaluated using the NAFLD activity score (NAS), in comparison to those in the control mice. Serum levels of glucose and free fatty acid and mRNA expression levels of pro-inflammatory markers in the liver were reduced by tofogliflozin treatment. Conversely, the proliferation of SGLT2 protein-expressing hepatoma cells was not inhibited and the insulin signaling in those cells was not altered by this agent. These findings suggest that tofogliflozin suppressed the early phase of obesity- and NAFLD-related liver carcinogenesis by attenuating chronic inflammation and steatosis in the liver, while the agent had no significant direct effect on the proliferation of hepatoma cells. Therefore, SGLT2 inhibitors may have a chemopreventive effect on obesity-related HCC. Citation Format: Yohei Shirakami, Koki Obara, Masaya Kubota, Hiroyasu Sakai, Takuji Tanaka, Masahito Shimizu, Mitsuru Seishima. Effects of the sodium glucose cotransporter 2 inhibitor tofogliflozin on hepatoma cell lines and liver tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 263.

Obesity, diabetes mellitus, and their related metabolic abnormalities are associated with increased risk of hepatocellular carcinoma (HCC). Sodium glucose cotransporter (SGLT)-2 inhibitors, recently approved anti-diabetic agents, are expected to ameliorate the abnormalities associated with metabolic syndrome including non-alcoholic fatty liver disease (NAFLD). In this study, we investigated the effects of the SGLT2 inhibitor tofogliflozin on the development of NAFLD-related liver tumorigenesis in C57BL/KsJ-+Leprdb/+Leprdb (db/db) obese and diabetic mice. The direct effects of tofogliflozin on human HCC cell proliferation were also evaluated. Male db/db mice were administered diethylnitrosamine-containing water for two weeks and were treated with tofogliflozin throughout the experiment. Tofogliflozin was kindly provided by Kowa Co., Ltd. and the chemical structure will be disclosed at the time of presentation at the meeting. In mice treated with tofogliflozin, the development of hepatic pre-neoplastic lesions was markedly suppressed, and hepatic steatosis and inflammation significantly reduced, as evaluated using the NAFLD activity score, in comparison to those in the control mice. Serum levels of glucose and free fatty acid and mRNA expression levels of pro-inflammatory markers in the liver were reduced by tofogliflozin treatment. Conversely, the proliferation of SGLT2 protein-expressing HCC cells was not inhibited by this agent. These findings suggest that tofogliflozin suppressed the early phase of obesity- and NAFLD-related liver carcinogenesis by attenuating chronic inflammation and steatosis in the liver, while the agent had no significant direct effect on the proliferation of HCC cells. Therefore, SGLT2 inhibitors may have a chemopreventive effect on obesity-related HCC. Citation Format: Yohei Shirakami, Koki Obara, Masaya Ohnishi, Takayasu Ideta, Hiroyasu Sakai, Takuji Tanaka, Masahito Shimizu, Mitsuru Seishima. Preventive effects of the sodium glucose cotransporter 2 inhibitor tofogliflozin on liver tumorigenesis in obese and diabetic mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2235. doi:10.1158/1538-7445.AM2017-2235