Inhibitory Effect of Dietary Perilla Oil Rich in the n-3 Polyunsaturated Fatty Acid α-Linolenic Acid on Colon Carcinogenesis in Rats

The inhibitory effect of dietary perilla oil rich in the n-3 polyunsaturated fatty acid α-linolenic acid against colon carcinogenesis was investigated in rats. Four groups of 26 F344 rats each received an intrarectal dose of 2 mg of N-methyl-N-nitrosourea 3 times a week for 2 weeks, and received a diet containing 12% perilla oil, 6% or 12% safflower oil (rich in the n-6 polyunsaturated fatty acid linoleic acid), or 12% palm oil (rich in saturated and monounsaturated fatty acids). At week 35, the incidence of colon cancer was significantly lower in perilla oil-fed rats than in other dietary groups; 19% vs. 46%, 56% and 58%. When examined at week 10, the concentration of fecal bile acids, known to be tumor promoters, was not significantly different among the dietary groups, and the intrarectal deoxycholic acid-induced colonic mucosal ornithine decarboxylase activity, a marker of tumor promotion, was significantly lower in perilla oil-fed group than in other groups. The serum and colonic mucosal fatty acid compositions and the blood plasma prostaglandin E₂ level directly reflected the fatty acid composition of each dietary fat. The results suggest that the anti-tumor-promoting effect of dietary perilla oil was a result of a decreased sensitivity of colonic mucosa to tumor promoters arising from the altered fatty acid composition in membrane phospholipid of colonic epithelial cells, and was not a consequence of a decrease of promoters such as bile acids.     

Inhibitory Effects of Chlorogenic Acid on Azoxymethane-induced Colon Carcinogenesis in Male F344 Rats

Modifying effects of chlorogenic acid (CA) on carcinogen-induced large bowel carcinogenesis was examined inrats. A total of 150 male F344 rats, 4 weeks old, were divided into 5 groups. At 6 weeks of age, groups 1-3 were givensubcutaneous injections of AOM (15 mg/kg body weight) once a week for three weeks. Group 2 was given the dietmixed with CA at the dose of 250 ppm during the initiation phase (5 weeks), and group 3 was exposed to the samediet during the post-initiation phase (32 weeks). Group 4 received the diet with CA throughout the experiment.Group 5 was maintained on the basal diet alone and served as a control. At the termination of the experiment (36weeks after the start), the incidence of colon tumors in group 2 and 3 demonstrated a tendency for decrease ascompared with group 1 although this did not attain significance At this time, the multiplicity of colon tumors ofgroup 2 was significantly smaller than in group 1. In this study, the anti-proliferating cell nuclear antigen (PCNA)indices for non-neoplastic cells of the colon mucosae in groups 2 and 3 were also smaller than in group 1. The datasuggest that CA has chemopreventive potential against colon carcinogenesis in rats like that showen in a hamstermodel with use of methylazoxymethanol acetate.     

Chemoprevention by Pravastatin, a 3-Hydroxy-3-methylglutaryl-coenzyme A Reductase Inhibitor, of N-Methyl-N-nitrosourea-induced Colon Carcinogenesis in F344 Rats

A potential chemopreventive action of pravastatin (Pr), a 3-hydroxy-3-methylglutaryl-coenzyme A redutase inhibitor, on colon carcinogenesis was evaluated in F344 rats. All rats at 7 weeks of age received an intrarectal dose of 2 mg of N -methyl- N -nitrosourea 3 times weekly for 2 weeks in experiment I (2 groups of 16 rats each), and for 3 weeks in experiment II (4 groups of 30 rats each). They were given drinking water containing 0 ppm (control) or 200 ppm Pr during weeks 1 to 40 in experiment I, and containing 0 ppm (control), 25 ppm, 5 ppm and 1 ppm Pr during weeks 4 to 40 in experiment II. The body weight gains, and food and water intakes were similar in all the groups. The incidence of colon carcinomas at termination of the experiment at week 40 was not different in the 200 ppm Pr and control groups in experiment I (63% vs. 69%), while it was significantly lower in the 25 ppm and 5 ppm groups, but not in the 1 ppm Pr group, compared with the control group in experiment II (50%, 48%, and 77% vs. 80%). This inhibitory effect of Pr against colon carcinogenesis was not related to the cholesterol-lowering effect of this agent. We postulate that Pr inhibits the promotion stage of colon carcinogenesis, perhaps through modulation of cholesterol synthesis in situ in the colonic mucosa, thereby suppressing farnesyl isoprenylation of growth-regulating proteins such as p21 ras.     

Inhibitory Effects of Nabumetone, a Cyclooxygenase-2 Inhibitor, and Esculetin, a Lipoxygenase Inhibitor, on N-Methyl-N-nitrosourea-induced Mammary Carcinogenesis in Rats

We investigated the modifying effects of nabumetone, a relatively selective cyclooxygenase-2 inhibitor, and esculetin, a lipoxygenase inhibitor, on N -methyl- N -nitrosourea(MNU)-induced mammary carcinogenesis in female Sprague-Dawley rats. A total of 124 rats, 6 weeks old, were divided into 6 groups. At 50 days of age, groups 1, 2, and 3 were treated with MNU (50 mg/kg body weight) by subcutaneous injection. From the age of 8 weeks, groups 2 and 4 were given 0.03% nabumetone in the diet and groups 3 and 5 were given 0.03% esculetin in the diet. All rats were necropsied at the termination (25 weeks after the start of experiment). The incidence and multiplicity of neoplasms in group 2 were significantly smaller than those in group 1 ( P <0.005 and P <0.001, respectively). The incidence of neoplasms in group 3 was also significantly smaller than that in group 1 ( P <0.05). These results indicate that the intake of nabumetone or esculetin during the time corresponding to the post initiation phase has a chemopreventive effect on MNU-induced mammary carcinogenesis in rats.     

Inhibition of Azoxymethane-induced Colon Carcinogenesis in Rats due to JTE-522, a Selective Cyclooxygenase-2 Inhibitor

Prostaglandin E2, which is produced by cyclooxygenase (COX) during arachidonic acid metabolism, is considered ‍to be related to colon carcinogenesis and selective COX-2 inhibitors may be effective for chemoprevention without ‍the adverse side effects of non-selective, nonsteroid anti-inflammatory drugs. Therefore, the influence of JTE-522 ‍(4-(4-cyclohexyl-2-methyloxazol-5-yl)-2-fluorobenzensulfonamide), a selective COX-2 inhibitor, was examined in ‍azoxymethane(AOM)-induced rat colon carcinogenesis. A total of 40 male F344 rats were randomly divided into ‍two groups. Group 1 received diet containing 0.015% JTE-522 and group 2 the normal diet without supplement as ‍a control group; one week later, all rats were administered axozymethane (AOM) s.c. at a dose of 15 mg/kg body ‍weight once a week for 3 successive weeks. At the termination of the experiment (30 weeks after the start), the ‍multiplicity of colon cancer in group 1 was significantly less than that of group 2. The proliferating cell nuclear ‍antigen (PCNA) indices for non-neoplastic cells of the colon mucosa in group 1 were also lower. These data thus ‍suggest that JTE-522 has chemopreventive potential against colon carcinogenesis with decrease of mucosal cell ‍proliferation in rats. ‍     

A Ferulic Acid Derivative, Ethyl 3-(4'-Geranyloxy-3-methoxyphenyl)-2-propenoate, as a New Candidate Chemopreventive Agent for Colon Carcinogenesis in the Rat

The inhibitory influence of ferulic acid (FA), a rice germ component, and its geranylated derivative 3-(4'-geranyloxy-3-methoxyphenyl)-2-propenoate (EGMP) on the post-initiation stage of azoxy-methane (AOM)-induced colon carcinogenesis was studied in male F344 rats given two s.c. injections of AOM (15 mg/kg body weight) during week 1. Diets containing EGMP or FA at doses of 0.1 or 0.2% were then fed for 3 weeks from week 2 to 5, when the animals were sacrificed. The numbers of aberrant crypt foci (ACF) and aberrant crypts (AC) per rat in the group given 0.2% FA were significantly decreased (P<0.001) as compared to the AOM alone group. Furthermore, the numbers of ACF and AC per rat fed the 0.2% and 0.1% EGMP were significantly reduced (P<0.001 and P<0.01, respectively). Colonic epithelial cells in S-phase, as measured by bromodeoxy-uridine (BrdU) labeling, in rats fed EGMP were significantly decreased in the 0.2 and 0.1% EGMP groups as compared to the AOM alone group (P<0.05). BrdU labeling indices in rats fed FA and EGMP assessed by a test using a coefficient for linear contrast were also significantly decreased as compared to the AOM alone value (P<0.05, P<0.01, respectively). The results indicate that FA and EGMP have inhibitory effects on ACF and AC development, EGMP being more potent, possibly due to stronger suppressive effects on cell proliferation. No toxic effects were observed in rats given either compound in terms of body and organ weights, and liver or kidney histology. The findings thus suggest that EGMP and FA, especially the former, might have potential as chemopreventive agents against colon tumor development.     

Anti-promoting Effect of Nordihydroguaiaretic Acid on N-Butyl-N-(4-hydroxybutyl)nitrosamine and Sodium Saccharin-induced Rat Urinary Bladder Carcinogenesis

The effects of oral administration of nordihydroguaiaretic acid (NDGA), an antioxidant and inhibitor of arachidonic acid metabolism, on rat bladder carcinogenesis were examined. Six-week-old male Fischer 344 rats were given drinking watar containing 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine for 4 weeks. Following this 4-week period, diet containing 5% sodium saccharin (SS) with or without 0.1% NDGA supplement was given to the rats for 36 weeks. The incidences of papillary or nodular (PN) hyperplasia and of papilloma in the group treated with SS plus NDGA were significantly lower than those in the group treated with SS alone. The number of PN hyperplasic foci per 10 cm of basement membrane in rats treated with SS plus NDGA was also lower than that in the group treated with SS alone. These results suggest that NDGA has an anti-tumor-promoting effect on rat bladder carcinogenesis.     

Inhibitory effect of cryptoporic acid E, a product from fungus Cryptoporus volvatus, on colon carcinogenesis induced with N-methyl-N-nitrosourea in rats and with 1,2-dimethylhydrazine in mice.

The antitumorigenic effect of cryptoporic acid E (CPA-E), a dimeric drimane sesquiterpenoid isolated from the fungus Cryptoporus volvatus, on colon carcinogenesis was investigated. Female F344 rats given an intrarectal instillation of 2 mg of N-methyl-N-nitrosourea 3 times weekly in weeks 1 and 2 were fed diet containing 0.2% CPA-E from week 3. Female ICR mice given 15 weekly intraperitoneal injections of 10 mg of 1,2-dimethylhydrazine/kg body weight during weeks 1 to 15 were fed diet containing 0.06% CPA-E from week 1. The experiment was terminated at week 35 for rats and at week 25 for mice. The incidence and the number of tumors per animal were reduced in CPA-E-fed animals compared to the controls: 31% vs. 75% (P less than 0.05) and 0.4 +/- 0.2 (SEM) vs. 0.9 +/- 0.2 (0.1 greater than P greater than 0.05) in rats, and 31% vs. 63% (0.1 greater than P greater than 0.05) and 0.4 +/- 0.2 vs. 2.4 +/- 0.8 (P less than 0.05) in mice (16 animals in each group). Intrarectal deoxycholic acid-induced colonic mucosal ornithine decarboxylase activity was significantly lowered in CPA-E-fed animals compared to controls. This shows an antipromoting activity of CPA-E against colon carcinogenesis. Thus, it was concluded that CPA-E inhibits colon cancer development in both rats and mice treated with 2 different colon carcinogens.     

Lack of Promoting Effects of α-Linolenic, Linoleic or Palmitic Acid on Urinary Bladder Carcinogenesis in Rats

Potential promoting effects of α-linolenic, linoleic and palmitic acids were investigated in a two-stage urinary bladder carcinogenesis model. In experiment 1, male F344 rats were given 0.05% N-butyl-N-(4-hydroxybutyl)nitrosainine (BBN) in their drinking water for 4 weeks and then basal diet containing 10%α-linolenic, 10% linoleic or 10% palmitic acid along with 0.2% butylated hydroxyanisole (BHA) as an antioxidant for 24 weeks. The development of tumors in the urinary bladder was not increased by treatment with any of the fatty acids. In experiment 2, male F344 rats were given 10%α-linolenic, 10% linoleic or 10% palmitic acid along with 0.2% BHA in their diet for 8 weeks without prior BBN treatment. The administration of fatty acids was not associated with any increase in the 5-bromo-2'-deoxyuridine labeling index of the urinary bladder epithelium. Serum and/or urine fatty acid Ievels increased in the cases of α-linolenic and linoleic acid treatments, but not with palmitic acid. Under the present experimental conditions neither the two polyunsaturated nor the one saturated fatty acid exerted any promoting effect on urinary bladder carcinogenesis.     

Inhibitory Effect of Orally Administered 5-Aminolevulinic Acid on Prostate Carcinogenesis in the FVB-Transgenic Adenocarcinoma of a Mouse Prostate (FVB-TRAMP) Model

Background: 5-aminolevulinic acid (5-ALA) is a constituent of mitochondrial electron carriers, heme and cytochrome c, which are crucial for aerobic energy metabolism and cell apoptosis. We investigated the chemopreventive efficacy of 5-ALA against prostate cancer using the FVB-transgenic adenocarcinoma of mouse prostate (FVB-TRAMP) model. Methods: Samples were collected from 24 FVB-TRAMP mice at 12 and 20 weeks of age (named the first and second sets, respectively). Sixteen mice (from the first set) were randomly allocated into 3 treatment groups: 1) control (no treatment), 2) low dose of 5-ALA (30 mg/kg/day), and 3) high dose of 5-ALA (300 mg/kg/day). Similarly, 8 mice were divided into 2 treatment groups: 1) control and 2) high dose of 5-ALA (300 mg/kg/day). 5-ALA was orally administered to mice before cancer onset, from 6 weeks of age. Results: In the control group, prostate cancer was pathologically detected in 33 and 50 % of mice at 12 and 20 weeks, respectively, while 25% of 12-week old mice in the low-dose group were affected and none of the high-dose group mice developed prostate cancer. Immunohistochemical analysis showed higher expression of cytochrome c oxidase subunit 4 (COX4) in the prostate gland of the high-dose group compared to the control (P = 0.018). Similarly, enzyme-linked immunosorbent assay using lysed prostate tissue revealed higher amounts of cytochrome c in the prostate of the high-dose group compared to the control (P = 0.021). Furthermore, western blot analysis showed higher level of cleaved caspase-3 in mice in the high-dose group diagnosed with high-grade prostatic intraepithelial neoplasia. Conclusion: Our results suggest that oral 5-ALA may support the functional expression of mitochondrial cytochrome c and COX4, leading to caspase 3-dependent apoptosis in carcinogenesis in FVB-TRAMP mice. Future clinical studies are warranted to confirm the chemopreventive value of 5-ALA in prostate carcinogenesis.     

Inhibitory Effects of Dietary Protocatechuic Acid and Costunolide on 7,12-Dimethylbenz[a]anthracene-induced Hamster Cheek Pouch Carcinogenesis

The modifying effects of dietary exposure to two natural products, protocatechuic acid (PCA) and Costunolide during the development of neoplasms in oral carcinogenesis initiated with 7,12-dimethyl-benz[ a ]anthracene (DMBA) were investigated in male Syrian golden hamsters. All hamsters except those in the test chemical alone and control groups received DMBA (0.5%) in mineral oil to the right buccal pouch 3 times per week for 4 or 6 weeks. At 13 weeks of age, the groups exposed to DMBA were fed diet containing PCA or Costunolide at a dose of 0.2 g/kg diet (200 ppm) for 17 weeks. The other groups consisted of hamsters given mineral oil alone for 6 weeks, or given 200 ppm PCA or Costunolide alone, or untreated. All animals were necropsied at the termination of the experiment (week 24). PCA or costunolide significantly decreased the tumor burden (P<0.001- P <0.05) and the extent of dysplastic areas (%) (P<0.001-P<0.05). PCA significantly decreased the mean number of AgNORs/nucleus (P<0.05). The BrdUrd-labeling index was reduced by dietary administration of test compounds, though not significantly. These results suggest that PCA and costunolide inhibited hamster buccal pouch carcinogenesis and such inhibition may be related to suppression of cell proliferation in the buccal mucosa. It was also found that telomerase activity expressed in neoplastic and preneoplastic lesions of hamster buccal pouch epithelium after DMBA treatment correlated with the histopathological degree of malignancy.     

Amelioration of 1,2 Dimethylhydrazine (DMH) Induced Colon Oxidative Stress,Inflammation and Tumor Promotion Response by Tannic Acid in Wistar Rats

Colon cancer is the third most common malignant neoplasm in the world and it remains an important causeof death, especially in western countries. The toxic environmental pollutant, 1, 2-dimethylhydrazine (DMH), isalso a colon-specific carcinogen. Tannic acid (TA) is reported to be effective against various types of chemicallyinduced toxicity and also carcinogenesis. In the present study, we evaluated the chemopreventive efficacy of TAagainst DMH induced colon toxicity in a rat model. Efficacy of TA against the colon toxicity was evaluated interms of biochemical estimation of antioxidant enzyme activities, lipid peroxidation, histopathological changesand expression of early molecular markers of inflammation and tumor promotion. DMH treatment inducedoxidative stress enzymes (p<0.001) and an early inflammatory and tumor promotion response in the colons ofWistar rats. TA treatment prevented deteriorative effects induced by DMH through a protective mechanismthat involved reduction of oxidative stress as well as COX-2, i-NOS, PCNA protein expression levels and TNF-α(p<0.001) release. It could be concluded from our results that TA markedly protects against chemically inducedcolon toxicity and acts plausibly by virtue of its antioxidant, anti-inflammatory and antiproliferative activities.     

Chemopreventive Effect of N-(2-Cyclohexyloxy-4-nitrophenyl)methane Sulfonamide (NS-398), a Selective Cyclooxygenase-2 Inhibitor, in Rat Colon Carcinogenesis Induced by Azoxymethane

Non-steroidal anti-inflammatory drugs (NSAIDs) such as sulindac and indomethacin inhibit colon carcinogenesis, and selective cyclooxygenase (COX)-2 inhibitors are considered to be potential chemopreventive agents without the side effects of usual NSAIDs. We reported that NS-398, N-(2-cyclohexyloxy-4-nitrophenyl)methane sulfonamide, suppressed the formation of preneoplastic lesions, aberrant crypt foci (ACF), induced by azoxymethane (AOM) in a short-term assay of rat colon carcinogenesis. In this study, we examined the effects of long-term NS-398 administration on rat colon carcinogenesis. After three AOM treatments at weekly intervals, a dose of 10 mg/kg of NS-398 in 5% Arabic gum solution was administered by gavage three times per week in group 2 until the termination of the experiment. Rats in group 1 were fed in a basal diet and given 5% Arabic gum solution alone after AOM treatment. At 40 weeks after the first AOM treatment, all rats were killed and the whole intestines including colon were examined. While the incidences of whole intestinal and colon neoplasms in group 1 were 84.6% and 80.8%, respectively, those in group 2 (given NS-398) were 51.9% and 44.4% respectively ( P =0.0177 and P =0.0103 by Fisher's exact test, respectively). The multiplicities in group 2 (0.67 ± 0.78 and 0.48 ± 0.58) were also decreased significantly compared with those (1.39 ± 1.10 and 1.08 ± 0.74) in group 1 ( P < 0.01 by Welch's method and P < 0.002 by Student's t test, respectively). In immunohistochemistry for proliferative cell nuclear antigen (PCNA), the PCNA-stained cell index (7.40 ± 0.5) in group 2 was significantly decreased from that in group 1 (14.03 ± 0.82) ( P < 0.001 by Welch's method). The results suggest that NS-398, a selective COX inhibitor, has a chemopreventive activity against colon carcinogenesis without side-effects such as gastric ulceration.     

Chemoprevention of 7,12-Dimethylbenz[a]anthracene-induced Mammary Carcinogenesis in Rat by the Combined Actions of Selenium, Magnesium, Ascorbic Acid and Retinyl Acetate

The chemopreventive actions of sodium selenite (SS), magnesium chloride (MC), ascorbic acid (AA) and retinyl acetate (RA), given singly or in combinations, on mammary carcinogenesis induced by 30 mg of 7,12-dimethylbenz[ a ]anthracene (DMBA) in female adult rats were evaluated. Administration of modulators was carried out from the age of 40±3 days to 240±3 days. When DMBA alone was given 100% of the rats developed mammary tumors. When modulators were given singly the tumor incidences were reduced to 51.77% (SS), 46.4% (MC), 57.1% (AA) and 48.1% (RA). When the modulators were given in combination of twos, the tumor incidences were further reduced to 29.5% (SS + MC), 31% (SS + AA), 29.6% (SS + RA), 25.9% (MC + AA), 31.8% (MC + RA) and 34.6% (AA + RA). Administration of modulators in combinations of threes resulted in still further reduction of tumor incidences to 22.2% (SS + MC + AA), 19.2% (SS + MC + RA), 16% (MC + AA + RA) and 23.1% (AA + RA + SS). When all four modulators were given concurrently the tumor incidence was only 12%. Further, the number of tumors per tumor-bearing animal declined with the increase in the number of agents used in combination for modulation.     

奥沙利铂对二甲肼诱导的结肠癌大鼠CD44V6、VEGF、survivin、Caspase-3和Caspase-7的影响

目的 研究奥沙利铂对结肠癌大鼠治疗的作用机制。方法 将42只SD大鼠均颈背部皮下注射二甲肼,每周注射 1次,连续注射5周。随机抽取2只大鼠切取直肠进行HE染色,病理学观察,确定结肠癌大鼠模型建立。将40只结肠癌大鼠随机分为模型组、奥沙利铂高、中、低剂量组,每组10只。另设正常组SD大鼠10只。奥沙利铂高剂量组（27.2 mg/kg）、中剂量组（13.6 mg/kg）、低剂量组（6.8 mg/kg）,给予1 ml 5%的葡萄糖注射液溶解,尾静脉注射给药,每3周给药一次,连续给药12周。正常组与模型组给予1 ml 5%的葡萄糖注射液代替。末次给药48 h后,通过颈脱位法处死大鼠。显微镜观察结肠组织中异变腺窝病灶(ACF)的个数。通过酶联免疫吸附（ELISA）法检测结肠癌大鼠血清中CD44V6和VEGF的含量变化。免疫蛋白印记（Western blot）法检测结肠癌组织中survivin、Caspase-3和Caspase-7的蛋白水平。结果 与模型组比较,奥沙利铂给药组结肠组织中ACF的数量明显减少。与正常对照组比较,模型组血清中CD44V6和VEGF的含量显著增加（P＜0.05）。与模型组相比,奥沙利铂高剂量组、中剂量组血清中CD44V6和VEGF的含量下降。其中奥沙利铂高剂量的效果最好,差异有统计学意义（P＜0.05）。与正常组相比,模型组、奥沙利铂给药组结肠癌组织中的survivin、Caspase-3和Caspase-7的蛋白水平均上升。与模型组相比,奥沙利铂给药组结肠癌组织中的survivin的蛋白水平降低;Caspase-3和Caspase-7的蛋白水平升高,差异有统计学意义（P＜0.05）。结论 奥沙利铂通过调控CD44V6、VEGF、survivin、Caspase-3和Caspase-7的水平,减少肿瘤血管的生成与转移、调节结肠癌组织中的细胞凋亡,从而达到治疗的目的。     

Anticancer Effect of COX-2 Inhibitor DuP-697 Alone and in Combination with Tyrosine Kinase Inhibitor (E7080) on Colon Cancer Cell Lines

Colorectal cancer remains one of the most common types of cancer and a leading cause of cancer deathworldwide. In this study, we aimed to investigate effects of DuP-697, an irreversible selective inhibitor of COX-2 on colorectal cancer cells alone and in combination with a promising new multi-targeted kinase inhibitorE7080. The HT29 colorectal cancer cell line was used. Real time cell analysis (xCELLigence system) wasconducted to determine effects on colorectal cell proliferation, angiogenesis was assessed with a chorioallantoicmembrane model and apoptosis was determined with annexin V staining. We found that DuP-697 alone exertedantiproliferative, antiangiogenic and apoptotic effects on HT29 colorectal cancer cells. For the antiproliferativeeffect the half maximum inhibition concentration (IC50) was 4.28510-8 mol/L. Antiangiogenic scores were 1.2,0.8 and 0.5 for 100, 10 and 1 nmol/L DuP-697 concentrations, respectively. We detected apoptosis in 52% ofHT29 colorectal cancer cells after administration of 100 nmol/L DuP-697. Also in combination with the thyrosinekinase inhibitor E7080 strong antiproliferative, antiangiogenic and apoptotic effects on HT29 colorectal cancercells were observed. This study indicates that DuP-697 may be a promising agent in the treatment of colorectalcancer. Additionally the increased effects observed in the combination with thyrosine kinase inhibitor give thepossibility to use lower doses of DuP-697 and E7080 which can avoid and/or minimize side effects.     

维生素E琥珀酸酯通过酸性神经磷脂酶-神经酰胺诱导胃癌细胞凋亡的机制研究

目的：探讨维生素E琥珀酸酯（VES）通过酸性神经磷脂酶（ASmase）-神经酰胺（Cer）诱导人胃癌细胞凋亡过程中对死亡受体信号通路以及氧化应激反应的影响。方法：将人胃癌SGC-7901细胞分为对照组、ASMase抑制剂地昔帕明（DES）组（12.5 μmol/L）、VES处理组（20 μg/mL）以及VES+DES组（12.5 μmol/L的DES预处理细胞2 h后加入20 μg/mL的VES）。在不同时间点用ELISA法测定ASMase活性,免疫荧光法检测Cer表达情况;处理24 h时用DAPI染色检测细胞凋亡率,Western blot法检测死亡受体信号通路蛋白Fas、死亡受体5（DR5）、caspase-8、caspase-9和PARP的蛋白表达水平,流式细胞术检测活性氧簇（ROS）水平。结果：VES处理细胞后ASMase活性在1.5 h时开始增加,同时Cer开始在细胞膜上的聚集增加,两者的表达水平分别在3、6 h时达到高峰,24 h的细胞凋亡率为（41.00±1.00）%;抑制ASMase活性显著降低了VES处理组细胞的凋亡率,Fas、DR5、c-caspase-8、c-caspase-9、c-PARP蛋白表达水平和氧化应激水平（P均 < 0.01）。结论：ASMase/Cer可能是VES通过死亡受体信号通路及氧化应激反应促进胃癌细胞发生凋亡的上游因子。     

Investigation of the Effect of Zebularine in Comparison to and in Combination with Trichostatin A on p21Cip1/Waf1/ Sdi1, p27Kip1, p57Kip2, DNA Methyltransferases and Histone Deacetylases in Colon Cancer LS 180 Cell Line

Background: The heart of the cell cycle regulatory machine is a group of enzymes named cyclin-dependent kinases (Cdks). The active form of these enzymes includes a kinase and its partner, a cyclin. The regulation of cyclin-Cdk complexes is provided by Cdk inhibitors (CKIs) such as Cip/Kip family comprising p21Cip1/Waf1/Sdi1, p27Kip1, and p57Kip2. The hypermethylation and deacetylation of Cip/Kip gene family seem to be frequent in numerous cancers. It has been indicated that increased expression of DNMTs and HDACs contributes to cancer induction. Previously, we reported the effect of DNA demethylating agents and histone deacetylase inhibitors on histone deacetylase 1, DNA methyltransferase 1, and CIP/KIP family in colon cancer. The current study was designed to evaluate the effect of zebularine in comparison to and in combination with trichostatin A (TSA) on p21Cip1/Waf1/Sdi1, p27Kip1, p57Kip2, DNA methyltransferases (DNMT1, 3a and 3b) and histone deacetylases (HDAC1, 2, and 3) genes expression, cell growth inhibition and apoptosis induction in colon cancer LS 180 cell line. Materials and Methods: The colon cancer LS 180 cell line was cultured and treated with zebularine and TSA. To determine cell viability, apoptosis, and the relative expression level of the genes, MTT assay, cell apoptosis assay, and qRT-PCR were done respectively. Results: Both compounds significantly inhibited cell growth, and induced apoptosis. Furthermore, both compounds increased p21Cip1/Waf1/Sdi1, p27Kip1, and p57Kip2 significantly. Additionally, zebularine and TSA decreased DNMTs and HDACs gene expression respectively. Conclusion: The zebularine and TSA can reactivate the CIP/KIP family through inhibition of DNMTs and HDACs genes activity.