Preventive effects of astaxanthin on diethylnitrosamine-induced liver tumorigenesis in C57/BL/KsJ-db/db obese mice.

AIM: Obesity and its related metabolic abnormalities, including oxidative stress and adipokine imbalance, are involved in liver carcinogenesis. The aim of the present study was to examine the effects of astaxanthin, a powerful biological antioxidant, on the development of diethylnitrosamine (DEN)-induced liver tumorigenesis in C57BL/KsJ-db/db (db/db) obese mice. METHODS: Male db/db mice were given a single i.p. injection of DEN (25 mg/kg bodyweight) at 2 weeks of age, and, subsequently, from 4 weeks of age, they were fed a diet containing 200 p.p.m. astaxanthin throughout the experiment. RESULTS: Twenty weeks of astaxanthin administration significantly inhibited the development of hepatocellular neoplasms (liver cell adenoma and hepatocellular carcinoma) and the hepatic expression of cyclin D1 mRNA compared with the basal diet group in DEN-treated db/db mice. Astaxanthin administration in DEN-treated experimental mice markedly reduced the derivatives of reactive oxygen metabolites/biological antioxidant potential ratio, which is a serum marker of oxidative stress, while increasing the mRNA expression of the antioxidant enzymes superoxide dismutase 2 and glutathione peroxidase 1 in the liver and white adipose tissue. The serum levels of adiponectin increased after astaxanthin administration in these mice. CONCLUSION: Dietary astaxanthin prevented the development of liver tumorigenesis in obese mice by improving oxidative stress and ameliorating serum adiponectin level. Therefore, astaxanthin may be useful in the chemoprevention of liver tumorigenesis in obese individuals.

[Bile duct injury and severe bleeding after endoscopic papillary large balloon dilation without sphincterotomy: a case report].

We report the case of an 80-year-old woman with multiple choledocholithiasis who suffered severe bleeding after endoscopic papillary large balloon dilation (EPLBD). Astriction by balloon tamponade and a covered, self-expandable, metallic stent failed. However, embolization using a transcatheter arterial coil stopped the bleeding. After hemostasis was achieved, a bile duct injury was observed. We presume that a bile duct stone, which had remained in the lower common bile duct, entered the balloon and the bile duct and caused the bile duct injury. This case emphasizes the need for careful attention during EPLBD.

A refractory duodenal ulcer with a biliary-duodenal fistula following the administration of bevacizumab.

A 65-year-old woman with recurrent breast cancer was repeatedly treated with bevacizumab, an anti-VEGF antibody. In addition, she was also frequently prescribed a nonsteroidal anti-inflammatory drug for abdominal pain. Melena was revealed 2 months after the final treatment with bevacizumab, and an endoscopic study revealed a duodenal ulcer (DU) that was resistant to anti-ulcer therapy. A cholangiography identified a biliary-duodenal fistula with bile juice leaking from the ulcer base. Therefore, a biliary stent was placed into the common bile duct for 3 months until the DU healed. This is the first case of a refractory DU with a biliary-duodenal fistula in a patient treated with bevacizumab.

Synergistic growth inhibition by acyclic retinoid and phosphatidylinositol 3-kinase inhibitor in human hepatoma cells.

BACKGROUND: A malfunction of RXRα due to phosphorylation is associated with liver carcinogenesis, and acyclic retinoid (ACR), which targets RXRα, can prevent the development of hepatocellular carcinoma (HCC). Activation of PI3K/Akt signaling plays a critical role in the proliferation and survival of HCC cells. The present study examined the possible combined effects of ACR and LY294002, a PI3K inhibitor, on the growth of human HCC cells. METHODS: This study examined the effects of the combination of ACR plus LY294002 on the growth of HLF human HCC cells. RESULTS: ACR and LY294002 preferentially inhibited the growth of HLF cells in comparison with Hc normal hepatocytes. The combination of 1 µM ACR and 5 µM LY294002, in which the concentrations used are less than the IC50 values of these agents, synergistically inhibited the growth of HLF, Hep3B, and Huh7 human HCC cells. These agents when administered in combination acted cooperatively to induce apoptosis in HLF cells. The phosphorylation of RXRα, Akt, and ERK proteins in HLF cells were markedly inhibited by treatment with ACR plus LY294002. Moreover, this combination also increased RXRE promoter activity and the cellular levels of RARß and p21(CIP1), while decreasing the levels of cyclin D1. CONCLUSION: ACR and LY294002 cooperatively increase the expression of RARß, while inhibiting the phosphorylation of RXRα, and that these effects are associated with the induction of apoptosis and the inhibition of cell growth in human HCC cells. This combination might therefore be effective for the chemoprevention and chemotherapy of HCC.

Enhanced development of azoxymethane-induced colonic preneoplastic lesions in hypertensive rats.

Metabolic syndrome is associated with an increased risk of colorectal cancer. This study investigated the impact of hypertension, a component of metabolic syndrome, on azoxymethane (AOM)-induced colorectal carcinogenesis using SHRSP/Izm (SHRSP) non-diabetic/hypertensive rats and SHRSP.Z-Leprfa/IzmDmcr (SHRSP-ZF) diabetic/hypertensive rats. Male 6-week-old SHRSP, SHRSP-ZF, and control non-diabetic/normotensive Wister Kyoto/Izm (WKY) rats were given 2 weekly intraperitoneal injections of AOM (20 mg/kg body weight). Two weeks after the last injection of AOM, the SHRSP and SHRSP-ZF rats became hypertensive compared to the control WKY rats. Serum levels of angiotensin-II, the active product of the renin-angiotensin system, were elevated in both SHRSP and SHRSP-ZF rats, but only the SHRSP-ZF rats developed insulin resistance, dyslipidemia, and hyperleptinemia and exhibited an increase in adipose tissue. The development of AOM-induced colonic preneoplastic lesions and aberrant crypts foci, was significantly accelerated in both SHRSP and SHRSP-ZF hypertensive rats, compared to WKY normotensive rats. Furthermore, induction of oxidative stress and exacerbation of inflammation were observed in the colonic mucosa and systemically in SHRSP and SHRSP-ZF rats. Our findings suggest that hypertension plays a role in the early stage of colorectal carcinogenesis by inducing oxidative stress and chronic inflammation, which might be associated with activation of the renin-angiotensin system.

Preventive effects of branched-chain amino acid supplementation on the spontaneous development of hepatic preneoplastic lesions in C57BL/KsJ-db/db obese mice.

Obesity and its associated disorders, such as non-alcoholic steatohepatitis, increase the risk of hepatocellular carcinoma. Branched-chain amino acids (BCAA), which improve protein malnutrition in patients with liver cirrhosis, reduce the risk of hepatocellular carcinoma in these patients with obesity. In the present study, the effects of BCAA supplementation on the spontaneous development of hepatic premalignant lesions, foci of cellular alteration, in db/db obese mice were examined. Male db/db mice were given a basal diet containing 3.0% of either BCAA or casein, a nitrogen-content-matched control of BCAA, for 36 weeks. On killing the mice, supplementation with BCAA significantly inhibited the development of foci of cellular alteration when compared with casein supplementation by inhibiting cell proliferation, but inducing apoptosis. BCAA supplementation increased the expression levels of peroxisome proliferator-activated receptor-γ, p21(CIP1) and p27(KIP1) messenger RNA and decreased the levels of c-fos and cyclin D1 mRNA in the liver. BCAA supplementation also reduced both the amount of hepatic triglyceride accumulation and the expression of interleukin (IL)-6, IL-1ß, IL-18 and tumor necrosis factor-α mRNA in the liver. Increased macrophage infiltration was inhibited and the expression of IL-6, TNF-α, and monocyte chemoattractant protein-1 mRNA in the white adipose tissue were each decreased by BCAA supplementation. BCAA supplementation also reduced adipocyte size while increasing the expression of peroxisome proliferator-activated receptor-α, peroxisome proliferator-activated receptor-γ and adiponectin mRNA in the white adipose tissue compared with casein supplementation. These findings indicate that BCAA supplementation inhibits the early phase of obesity-related liver tumorigenesis by attenuating chronic inflammation in both the liver and white adipose tissue. BCAA supplementation may be useful in the chemoprevention of liver tumorigenesis in obese individuals.

Cisplatin and ultra-violet-C synergistically down-regulate receptor tyrosine kinases in human colorectal cancer cells.

BACKGROUND: Platinum-containing anti-cancer drugs such as cisplatin are widely used for patients with various types of cancers, however, resistance to cisplatin is observed in some cases. Whereas we have recently reported that high dose UV-C (200 J/m²) induces colorectal cancer cell proliferation by desensitization of EGFR, which leads oncogenic signaling in these cells, in this study we investigated the combination effect of low dose cisplatin (10 µM) and low dose UV-C (10 J/m²) on cell growth and apoptosis in several human colorectal cancer cells, SW480, DLD-1, HT29 and HCT116. RESULTS: The combination inhibited cell cycle and colony formation, while either cisplatin or UV-C alone had little effect. The combination also induced apoptosis in these cells. In addition, the combination caused the downregulation of EGFR and HER2. Moreover, UV-C alone caused the transient internalization of the EGFR, but with time EGFR recycled back to the cell surface, while cisplatin did not affect its localization. Surprisingly, the combination caused persistent internalization of the EGFR, which results in the lasting downregulation of the EGFR. CONCLUSIONS: The combination of low dose cisplatin and low dose UV-C synergistically exerted anti-cancer effect by down-regulating RTK, such as EGFR and HER2. These findings may provide a novel strategy for the treatment of patients with colorectal cancer.

Preventive effects of curcumin on the development of azoxymethane-induced colonic preneoplastic lesions in male C57BL/KsJ-db/db obese mice.

Obesity-related metabolic abnormalities include a state of chronic inflammation and adipocytokine imbalance, which increase the risk of colon cancer. Curcumin, a component of turmeric, exerts both cancer preventive and antiinflammatory properties. Curcumin is also expected to have the ability to reverse obesity-related metabolic derangements. The present study examined the effects of curcumin on the development of azoxymethane (AOM)-induced colonic premalignant lesions in C57BL/KsJ-db/db (db/db) obese mice. Feeding with a diet containing 0.2% and 2.0% curcumin caused a significant reduction in the total number of colonic premalignant lesions compared with basal diet-fed mice. The expression levels of tumor necrosis factor-α, interleukin-6, and cyclooxygenase-2 (COX-2) mRNAs on the colonic mucosa of AOM-treated mice were significantly decreased by curcumin administration. Dietary feeding with curcumin markedly activated AMP-activated kinase, decreased the expression of COX-2 protein, and inhibited nuclear factor-κB activity on the colonic mucosa of AOM-treated mice. Curcumin also increased the serum levels of adiponectin while conversely decreasing the serum levels of leptin and the weights of fat. In conclusion, curcumin inhibits the development of colonic premalignant lesions in an obesity-related colorectal carcinogenesis model, at least in part, by attenuating chronic inflammation and improving adipocytokine imbalance. Curcumin may be useful in the chemoprevention of colorectal carcinogenesis in obese individuals.

Renin-angiotensin system inhibitors suppress azoxymethane-induced colonic preneoplastic lesions in C57BL/KsJ-db/db obese mice.

Obesity-related metabolic abnormalities, including chronic inflammation and oxidative stress, increase the risk of colorectal cancer. Dysregulation of the renin-angiotensin system (RAS) also plays a critical role in obesity-related metabolic disorders and in several types of carcinogenesis. In the present study, we examined the effects of an angiotensin-converting enzyme (ACE) inhibitor and angiotensin-II type 1 receptor blocker (ARB), both of which inhibit the RAS, on the development of azoxymethane (AOM)-initiated colonic premalignant lesions in C57BL/KsJ-db/db (db/db) obese mice. Male db/db mice were given 4 weekly subcutaneous injections of AOM (15 mg/kg body weight), and then, they received drinking water containing captopril (ACE inhibitor, 5mg/kg/day) or telmisartan (ARB, 5mg/kg/day) for 7 weeks. At sacrifice, administration of either captopril or telmisartan significantly reduced the total number of colonic premalignant lesions, i.e., aberrant crypt foci and ß-catenin accumulated crypts, compared to that observed in the control group. The expression levels of TNF-α mRNA in the colonic mucosa of AOM-treated db/db mice were decreased by captopril and telmisartan. Captopril lowered the expression levels of TNF-α, IL-1ß, IL-6, and PAI-1 mRNAs, while telmisartan lowered the expression levels of COX-2, IL-1ß, IL-6, and PAI-1 mRNAs in the white adipose tissues of these mice. In addition, these agents significantly reduced the levels of urinary 8-OHdG, a surrogate marker of oxidative damage to DNA, in the experimental mice. These findings suggested that both ACE inhibitor and ARB suppress chemically-induced colon carcinogenesis by attenuating chronic inflammation and reducing oxidative stress in obese mice. Therefore, targeting dysregulation of the RAS might be an effective strategy for chemoprevention of colorectal carcinogenesis in obese individuals.

Pitavastatin suppresses diethylnitrosamine-induced liver preneoplasms in male C57BL/KsJ-db/db obese mice.

BACKGROUND: Obesity and related metabolic abnormalities, including inflammation and lipid accumulation in the liver, play a role in liver carcinogenesis. Adipocytokine imbalances, such as decreased serum adiponectin levels, are also involved in obesity-related liver tumorigenesis. In the present study, we examined the effects of pitavastatin - a drug used for the treatment of hyperlipidemia - on the development of diethylnitrosamine (DEN)-induced liver preneoplastic lesions in C57BL/KsJ-db/db (db/db) obese mice. METHODS: Male db/db mice were administered tap water containing 40 ppm DEN for 2 weeks and were subsequently fed a diet containing 1 ppm or 10 ppm pitavastatin for 14 weeks. RESULTS: At sacrifice, feeding with 10 ppm pitavastatin significantly inhibited the development of hepatic premalignant lesions, foci of cellular alteration, as compared to that in the untreated group by inducing apoptosis, but inhibiting cell proliferation. Pitavastatin improved liver steatosis and activated the AMPK-α protein in the liver. It also decreased free fatty acid and aminotransferases levels, while increasing adiponectin levels in the serum. The serum levels of tumor necrosis factor (TNF)-α and the expression of TNF-α and interleukin-6 mRNAs in the liver were decreased by pitavastatin treatment, suggesting attenuation of the chronic inflammation induced by excess fat deposition. CONCLUSIONS: Pitavastatin is effective in inhibiting the early phase of obesity-related liver tumorigenesis and, therefore, may be useful in the chemoprevention of liver cancer in obese individuals.

Risk factors for the development of esophageal candidiasis among patients in community hospital.

The aim of this study was to clarify risk factors for esophageal candidiasis (EC) in immunocompetent patients in a community hospital. 7736 patients who underwent esophagogastroduodenoscopy at our hospital from April 2012 to July 2018 were enrolled. The relationships between EC and the following factors: age, gender, body mass index, lifestyle, lifestyle-related diseases, medication, and endoscopic findings were analyzed. EC was observed in 184 of 7736 cases (2.4% morbidity rate). Multivariate analysis revealed that significant risk factors for the development of EC were: diabetes mellitus {odds ratio (OR): 1.52}, proton pump inhibitor (PPI) use (OR: 1.69), atrophic gastritis (AG) (OR: 1.60), advanced gastric cancer (OR: 4.66), and gastrectomy (OR: 2.32). When severe EC (Kodsi grade ≥ II) was compared to mild EC (grade I), the most significant risk factors were advanced gastric cancer (OR: 17.6) and gastrectomy (OR: 23.4). When considering the risk of AG and PPI use with EC development, the risk increased as follows: AG (OR: 1.59), PPI use (OR: 2.25), and both (OR: 3.13). PPI use, AG, advanced gastric cancer and post-gastrectomy are critical risk factors for the development of EC. We suggest close monitoring for EC development when PPIs are administered to patients with these factors.

Effects of antithrombotic drugs on the results of fecal immunochemical test in colorectal neoplasms screening.

Fecal immunochemical test (FIT) is widely used as a colorectal cancer screening tool. Antithrombotic drugs may affect the screening performance of FIT for colorectal tumors. The aim of this study was to clarify the effect of antithrombotic agents on FIT accuracy in screening for colorectal neoplasms. This retrospective study enrolled a total of 758 patients who underwent both FIT and total colonoscopy. The effect of antithrombotic drugs on FIT accuracy in detecting colorectal neoplasms (CN), including colorectal cancer (CRC), advanced adenoma (AA), and non-advanced adenoma (NAA), was examined. Of the 758 patients, 144 (19%) received antithrombotic drugs (administration group). In administration group, 61/144 (42%) cases had CN [CRC:14, AA:15, NAA:32] and 217/614 (35%) cases had CN (CRC:43, AA:56, NAA:118) in non-administration group. The prevalence of CN was not significantly different between the two groups (p = 0.1157). There was no significant difference in sensitivity or specificity of the detection of all types of CN with or without taking antithrombotic drugs. Neither the positive predictive value nor negative predictive value of FIT was affected by antithrombotic drug administration. Taking antithrombotic drugs may not have a large impact on sensitivity, specificity, positive predictive value, or negative predictive value of FIT in screening for CN.

Alpha-glucosidase inhibitor use is associated with decreased colorectal neoplasia risk in patients with type 2 diabetes mellitus receiving colonoscopy: a retrospective study.

PURPOSE: The purpose of this study was to clarify the factors that influence the incidence of colorectal neoplasia in patients with type 2 diabetes mellitus (DM). STUDY DESIGN AND SETTING: Among a total of 1176 patients who underwent total colonoscopy at our hospital, we retrospectively analyzed 168 patients with type 2 DM. Univariate and multivariate logistic regression analyses were then performed to identify the risk factors associated with colorectal neoplasia. RESULTS: A multivariate analysis of these patients demonstrated that male gender (odds ratio [OR] = 4.04, 95% confidence interval [CI] = 1.67-10.37, p = 0.002), taking statins (OR = 4.59, 95% CI = 1.69-13.43, p = 0.003), taking alpha glucosidase inhibitor (α-GI) (OR = 0.35, 95% CI = 0.13-0.87, p = 0.023) and taking low-dose aspirin (LDA) (OR = 0.32, 95% CI = 0.10-0.95, p = 0.040) were independent factors associated with an increased (male gender and statins) or decreased (α-GI and LDA) risk of colorectal neoplasia. CONCLUSIONS: While male gender and taking statins are risk factors, taking α-GI as well as LDA may reduce the risk of colorectal neoplasia in patients with type2 DM.

The Role of Indoleamine 2,3-Dioxygenase in Diethylnitrosamine-Induced Liver Carcinogenesis.

Indoleamine 2,3-dioxygenase (IDO), a tryptophan-catabolizing intracellular enzyme of the L-kynurenine pathway, causes preneoplastic cells and tumor cells to escape the immune system by inducing immune tolerance; this mechanism might be associated with the development and progression of human malignancies. In the present study, we investigated the role of IDO in diethylnitrosamine (DEN)-induced hepatocarcinogenesis by using IDO-knockout (KO) mice. To induce hepatocellular carcinoma (HCC), hepatic adenoma, and preneoplastic hepatocellular lesions termed foci of cellular alteration (FCA), male IDO-wild-type (WT) and IDO-KO mice with a C57BL/6J background received a single intraperitoneal injection of DEN at 2 weeks of age. The mice were sacrificed to evaluate the development of FCA and hepatocellular neoplasms. HCC overexpressed IDO and L-kynurenine compared to surrounding normal tissue in the DEN-treated IDO-WT mice. The number and cell proliferative activity of FCAs, and the incidence and multiplicity of HCC were significantly greater in the IDO-WT than in the IDO-KO mice. The expression levels of the IDO protein, of L-kynurenine, and of IFN-γ, COX-2, TNF-α, and Foxp3 mRNA were also significantly increased in the DEN-induced hepatic tumors that developed in the IDO-WT mice. The mRNA expression levels of CD8, perforin and granzyme B were markedly increased in hepatic tumors developed in IDO-KO mice. Moreover, Foxp3-positive inflammatory cells had infiltrated into the livers of DEN-treated IDO-WT mice, whereas fewer cells had infiltrated into the livers of IDO-KO mice. Induction of IDO and elevation of L-kynurenine might play a critical role in both the early and late phase of liver carcinogenesis. Our findings suggest that inhibition of IDO might offer a promising strategy for the prevention of liver cancer.

Pentoxifylline prevents nonalcoholic steatohepatitis-related liver pre-neoplasms by inhibiting hepatic inflammation and lipogenesis.

Nonalcoholic steatohepatitis (NASH) has gained attention as a hepatic manifestation associated with metabolic syndrome and one of the causes for chronic liver damage leading to hepatocellular carcinoma. Although no standard medicinal treatment for NASH has been established, pentoxifylline (PTX), a medicine used to improve circulation, has recently been reported to ameliorate the histopathological appearance of NASH. In the present study, we investigated the effects of PTX on the development of NASH and diethylnitrosamine-induced liver tumorigenesis in C57BLKS/J- +Lepr/+Lepr obese and diabetic mice, which are considered a rodent model for NASH-related hepatocarcinogenesis. Mice were administered diethylnitrosamine, and then they received water with or without PTX. At the time of sacrifice, the development of hepatic pre-neoplastic lesions was significantly suppressed in the PTX groups. Hepatic triglyceride contents were decreased by PTX administration. The serum levels of triglyceride, free fatty acid, and alanine aminotransferase were all decreased by PTX treatment, as was the mRNA expression of proinflammatory cytokines, macrophage-inducing chemokines, and several lipogenic genes in the liver. In-vitro studies also showed that PTX treatment decreased the expression of several lipogenic genes and chemokines in cell lines. These findings suggest that PTX prevents NASH-related liver tumorigenesis by attenuating chronic hepatic inflammation and decreasing lipogenic gene expression in the liver.

Development of a Novel Scoring System for Predicting the Risk of Colorectal Neoplasia: A Retrospective Study.

OBJECTIVE: The purpose of this study was to develop a novel scoring system to screen subjects who have a high risk for colorectal neoplasia. STUDY DESIGN AND SETTING: We retrospectively analyzed 1061 subjects undergoing total colonoscopy (TCS) for the first time at Gihoku Kosei Hospital. The characteristics and habits of the subjects were analyzed using a multivariate logistic regression analysis. The risk score was established according to each odds ratio of the individual risk factors, and the correlations between the sum of the risk scores and the prevalence of colorectal neoplasia for each individual were evaluated. RESULTS: Age 45-59 (risk score: 2 points) and ≥60 (3 points), male gender (1 point), and habitual alcohol consumption ≥21g daily (1 point) were extracted as the significant risk factors for colorectal neoplasia. When the risk groups were determined by summing up these risk scores, the prevalence rates of colorectal neoplasia were 8.8% for the low risk group (0-2 points), 30.5% for the low-moderate risk group (3 points), 39.1% for the high-moderate risk group (4 points), and 57.6% for the high risk group (5 points). In comparison with the low risk group, the odds ratio of the low-moderate risk, the high-moderate risk, and the high risk groups were 4.6, 6.7, and 14.1 folds, respectively. CONCLUSION: Our scoring system, which linearly correlates with the prevalence rate of colorectal neoplasia, may be an effective tool for screening the subjects who have a high risk for colorectal neoplasia. These subjects, therefore, should be recommended to undergo TCS.

Metformin suppresses diethylnitrosamine-induced liver tumorigenesis in obese and diabetic C57BL/KsJ-+Leprdb/+Leprdb mice.

Obesity and related metabolic disorders, such as diabetes mellitus, raise the risk of liver carcinogenesis. Metformin, which is widely used in the treatment of diabetes, ameliorates insulin sensitivity. Metformin is also thought to have antineoplastic activities and to reduce cancer risk. The present study examined the preventive effect of metformin on the development of diethylnitrosamine (DEN)-induced liver tumorigenesis in C57BL/KsJ-+Leprdb/+Leprdb (db/db) obese and diabetic mice. The mice were given a single injection of DEN at 2 weeks of age and subsequently received drinking water containing metformin for 20 weeks. Metformin administration significantly reduced the multiplicity of hepatic premalignant lesions and inhibited liver cell neoplasms. Metformin also markedly decreased serum levels of insulin and reduced insulin resistance, and inhibited phosphorylation of Akt, mammalian target of rapamycin (mTOR), and p70S6 in the liver. Furthermore, serum levels of leptin were decreased, while those of adiponectin were increased by metformin. These findings suggest that metformin prevents liver tumorigenesis by ameliorating insulin sensitivity, inhibiting the activation of Akt/mTOR/p70S6 signaling, and improving adipokine imbalance. Therefore, metformin may be a potent candidate for chemoprevention of liver tumorigenesis in patients with obesity or diabetes.

Effects of indoleamine 2,3-dioxygenase inhibitor in non-Hodgkin lymphoma model mice.

Indoleamine 2,3-dioxygenase (IDO) catalyzes the rate-limiting step in the metabolism of tryptophan along the kynurenine pathway. In tumors, increased IDO activity inhibits proliferation and induces apoptosis of T cells and natural killer cells. We investigated the therapeutic potential of IDO inhibitor 1-methyl-D-tryptophan (D-1MT) with cyclophosphamide (CY) in a mouse model of lymphoma. To examine the effect of D-1MT, mice were killed on day 28. Serum concentrations of L-kynurenine and L-tryptophan were measured by high-performance liquid chromatography. Regulatory T cells (Tregs) were counted by flow cytometry, and mRNA expressions of IDO1, Foxp3, IFN-γ, and COX-2 were examined by quantitative real-time reverse transcription-polymerase chain reaction. D-1MT+CY combination treatment significantly inhibited tumor growth as compared to either treatment alone. There were no significant differences in the serum L-kynurenine/L-tryptophan ratio or the IDO1 expression level in the tumors among the treatment groups. The expression levels of IFN-γ and COX-2 mRNA in tumor-draining lymph nodes (TDLNs) were found to be significantly up-regulated in the CY and D-1MT+CY groups. The number of Tregs in TDLNs in the D-1MT+CY group was significantly lower than that in CY groups on day 17. These results suggest that D-1MT in combination with CY is an effective treatment for lymphoma in a mouse model.

Combination of bevacizumab and acyclic retinoid inhibits the growth of hepatocellular carcinoma xenografts.

The prognosis of patients with hepatocellular carcinoma (HCC) is poor and the development of effective treatments for this malignancy, including combination chemotherapy, is required. This study examined the possible combined inhibitory effects of bevacizumab, an anti-vascular endothelial growth factor monoclonal antibody, and acyclic retinoid (ACR), which can prevent the development of HCC, on the growth of Huh7 human HCC cells. Xenograft tumors were produced by subcutaneously injecting Huh7 cells into nude mice. Starting 1 wk after the tumor cell injection, the mice were treated with bevacizumab alone (5 mg/kg body weight, subcutaneous injection, twice a week), ACR alone (given in a diet containing 0.03%), or their combination for 6 wk, and the effects of these regimens on xenograft growth were examined. Combined treatment with bevacizumab plus ACR significantly suppressed the growth of Huh7 xenografts. The combination of these agents significantly inhibited the phosphorylation of the Akt protein in tumor tissues. With combination therapy, the population of Ki-67-positive cells in xenografts decreased, while that of TUNEL-positive cells increased. The combination of bevacizumab and ACR exerts growth-suppressing effects on HCC cells by inhibiting cell proliferation and inducing apoptosis. This combination might be an effective regimen for the treatment of HCC.

Non-alcoholic steatohepatitis and preneoplastic lesions develop in the liver of obese and hypertensive rats: suppressing effects of EGCG on the development of liver lesions.

Non-alcoholic steatohepatitis (NASH), which involves hepatic inflammation and fibrosis, is associated with liver carcinogenesis. The activation of the renin-angiotensin system (RAS), which plays a key role in blood pressure regulation, promotes hepatic fibrogenesis. In this study, we investigated the effects of (-)-epigallocatechin-3-gallate (EGCG), a major component of green tea catechins, on the development of glutathione S-transferase placental form (GST-P)-positive (GST-P(+)) foci, a hepatic preneoplastic lesion, in SHRSP.Z-Lepr(fa)/IzmDmcr (SHRSP-ZF) obese and hypertensive rats. Male 7-week-old SHRSP-ZF rats and control non-obese and normotensive WKY rats were fed a high fat diet and received intraperitoneal injections of carbon tetrachloride twice a week for 8weeks. The rats were also provided tap water containing 0.1% EGCG during the experiment. SHRSP-ZF rats presented with obesity, insulin resistance, dyslipidemia, an imbalance of adipokines in the serum, and hepatic steatosis. The development of GST-P(+) foci and liver fibrosis was markedly accelerated in SHRSP-ZF rats compared to that in control rats. Additionally, in SHRSP-ZF rats, RAS was activated and inflammation and oxidative stress were induced. Administration of EGCG, however, inhibited the development of hepatic premalignant lesions by improving liver fibrosis, inhibiting RAS activation, and attenuating inflammation and oxidative stress in SHRSP-ZF rats. In conclusion, obese and hypertensive SHRSP-ZF rats treated with a high fat diet and carbon tetrachloride displayed the histopathological and pathophysiological characteristics of NASH and developed GST-P(+) foci hepatic premalignant lesions, suggesting the model might be useful for the evaluation of NASH-related liver tumorigenesis. EGCG might also be able to prevent NASH-related liver fibrosis and tumorigenesis.