Expression of Metallothionein after Administration of Aspirin,Vitamin C or Zinc Supplement in the DMH Induced Colon Carcinoma in Rat

Background: Chemoprevention refers to the use of specificnatural or synthetic chemical agents to suppress thedevelopment and progression to carcinoma. The purpose of this study was to assess the effect of aspirin, vitamin Cor zinc on the metallothionein (MT) mRNA gene expression as well as MT protein content byimmunohistochemistryandradioimmunoassay (RIA) in 1, 2-dimethyl hydrazine (DMH) induced cancerous colonic tissuein rats. Methods:Rats were randomly divided into three groups, group 1 (aspirin), group 2 (vitamin C) group 3 (zinc), each of whichwas further sub divided into two groups and given subcutaneous injections of DMH (30 mg/kg body weight) twice aweek for 3 months and sacrificed at either 4 months (A-precancer model) or at 6 months (B-cancer model).The controlgroups were administered 0.5 ml saline subcutaneously. All the 3 groups were simultaneouslyadministered aspirin,vitamin Cor zinc supplement respectively from the beginning till the end of the study. Results: It was observed thatrats co-treated with aspirin, vitamin C or zinc resulted in a significant increase in the colonic MT mRNA expression inthe precancer and cancer model as compared to the saline only controls. MT protein expression showed a 60%, 64%and 78% immunopositivity in the co-treated groups respectively.The mean MT content in the precancer and the cancermodel was restored to near normal levels in all the three co-treated groups. Conclusion: These results suggest thatco-administration of aspirin, vitamin C or zinc resulted in a significant increase in MT mRNA gene expression, MTprotein expression and MT protein content which could possibly be one of the reasons for a chemo protective effectagainst progression to colonic cancer in a chemically induced DMH model in rat.Zinc supplement had a greater effecton metallothionein expression than aspirin or vitamin C.     

Zinc and zinc related enzymes in precancerous and cancerous tissue in the colon of dimethyl hydrazine treated rats

Trace element zinc deficiency or excess is implicated in the development or progression of some cancers. The exact role of zinc in the etiology of colon cancer is unclear. To cast light on this question, an experimental model of colon carcinogenesis was applied here. Six week old rats were given sub cutaneous injections of DMH (30 mg/kg body weight) twice a week for three months and sacrificed after 4 months (precancer model) and 6 months (cancer model). Plasma zinc levels showed a significant decrease (p<0.05) at 4 months and a greater significant decrease at 6 months (p<0.01) as compared with controls. In the large intestine there was a significant decrease in tissue zinc levels (p<0.005) and in CuZnSOD, and alkaline phosphatase activity (p<0.05) in the pre-cancerous model and a greater significant decrease in tissue zinc (p<0.0001), and in CuZnSOD and alkaline phosphatase activity (p<0.001), in the carcinoma model. The tissue zinc levels showed a significant decrease in the small intestine and stomach (p<0.005) and in liver (p<0.05) in the cancer model. 87% of the rats in the precancer group and 92% rats in the cancer group showed histological evidence of precancerous lesions and carcinomas respectively in the colon mucosa. This study suggests that the decrease in plasma zinc, tissue zinc and activity of zinc related enzymes are associated with the development of preneoplastic lesions and these biochemical parameters further decrease with progression to carcinoma in the colon.     

Associations of Probiotics with Vitamin D and Leptin Receptors and their Effects on Colon Cancer

Colorectal cancer (CRC) is one of most common causes of cancer-related death worldwide. Recent studieshave suggested that microbial and environmental factors including diet and lifestyle can impact on colon cancerdevelopment. Vitamin D deficiency and dysfunction of vitamin D receptor (VDR) also correlate with coloncancer. Moreover, leptin, a 16-kDa polypeptide, participates in the regulation of food intake and is associatedwith other environmental factors affecting colon cancer through the leptin receptor. Altered levels of serum leptinand patterns of expression of its receptor (LPR) may be observed in human colon tumours. Furthermore, thecollected data from in vitro and in vivo studies have indicated that consuming probiotic non-pathogenic lacticacid bacteria have beneficial effects on colon cancer. Probiotics, inflammation and vitamin D/VDR have beencorrelated with leptin and its receptor and are also with colon cancer. Thus, in this paper, we review recentprogress on the roles of probiotic, vitamin D/VDR and leptin/LPR in inflammation and colon cancer.     

维生素C作用的防癌与致癌双重性

本文对维生素C (VitC)在癌症预防及治疗中的作用的最新进展作了简要综述 ,认为VitC可能具有双重作用 ,应用VitC预防癌症应持慎重态度     

Genetic Variation in Glutamate Carboxypeptidase II and Interaction with Dietary Natural Vitamin C May Predict Risk for Adenomatous Polyp Occurrence

Background: The C1561T variant of the glutamate carboxypeptidase II (GCPII) gene is critical for naturalmethylfolylpolyglutamte (methylfolate) absorption, and has been associated with perturbations in folatemetabolism and disease susceptibility. However, little is known on C1561T-GCPII as a risk factor for colorectalcancer. Therefore, this study examined whether C1561T-GCPII influences folate metabolism and adenomatouspolyp occurrence. Materials and Methods: 164 controls and 38 adenomatous polyp cases were analysed todetermine blood folate and plasma homocysteine (Hcy) level, dietary intake of natural methylfolate, syntheticpteroylglutamic acid (PteGlu), vitamin C and C1561T-GCPII genotype. Results: In controls and cases, 7.3 and18.4 percent of subjects respectively, were found to have the CT genotype, increasing the risk for adenomatouspolyp occurrence 2.86 times (95% CI:1.37-8.0, p=0.035). Total dietary folate, methylfolate and PteGlu intakeand the level of erythrocyte folate and plasma Hcy did not predict the occurrence of an adenomatous polyp.However, dietary natural vitamin C intake was associated with adenomatous polyp risk within C1561T-GCPIICT genotype subjects (p=0.037). Conclusions: The findings suggest that C1561T-GCPII variation may beassociated with risk for adenomatous polyp, and vitamin C may modify risk by interacting with the variantgene, its expression product and/or folate substrates.     

常见肿瘤患者血清维生素A,E,C水平

本文报告２６０例恶性肿瘤患者血清维生素Ａ、Ｅ、Ｃ水平的测定结果。发现除慢性白血病外，蓁７种恶性肿瘤患者血清维生素Ａ水平平均显著低于健康人（Ｐ＜０．０１）；急性白血，肝癌、食管癌患者血清维生素Ｅ水平显著低于健康人（Ｐ＜０．０５）；急性粒细胞白血病、急性单核细胞白血病、肝癌患者血维生素Ｃ水平显著低于健康人（Ｐ＜０．０１）。本研究工作为维生素Ａ、Ｅ、Ｃ药物在肿瘤临床上的应用提供了参考。     

The effect of vagotomy and pyloroplasty on colorectal tumor induction in the rat.

Epidemiologic studies have suggested that vagotomy increases subsequent colorectal cancer risk. This hypothesis was investigated in the rat 1,2 dimethylhydrazine (DMH) colorectal carcinogenesis model. Eighty-five rats were divided into four groups having either truncal vagotomy and Heineke-Mickulicz pyloroplasty, pyloroplasty alone, laparotomy alone, and anesthesia alone. After recovery from the procedures, colon tumors were induced with five injections of DMH. Results of carcinogenesis show a trend towards increased incidence and yield of colorectal and duodenal tumors after vagotomy, though this was not statistically significant, perhaps because the high postoperative mortality from vagotomy diminished the power of the study.     

维生素C对A549细胞增殖、凋亡及Caspase-3、Survivin表达的影响

背景与目的维生素C作为一种抗氧化剂,对多种肿瘤均有抑制作用,本研究旨在探讨维生素C对肺癌细胞株A549的增殖、凋亡的影响及其诱导A549细胞凋亡的可能机制。方法在体外培养的肺癌A549细胞株中加入不同浓度的维生素C,采用细胞生长曲线及克隆形成实验检测细胞生长情况;用流式细胞仪检测细胞周期的影响及凋亡率;用RT-PCR方法检测肺癌细胞株A549中Caspase-3、Survivin的表达差异。结果400μg/mL、4mg/mL浓度组维生素C明显抑制A549细胞的增殖,流式细胞仪检测细胞被阻止在G0/G1期及S期,且随着时间的延长细胞凋亡逐渐增多,RT-PCR检测维生素C可以上调Caspase-3mRNA的表达,并且随着时间的延长Caspase-3mRNA的表达逐渐增强,对Survivin mRNA的表达无确切作用。结论维生素C呈时间和剂量依赖性抑制A549细胞的增殖,并使A549细胞阻止在G0/G1期及S期,并呈时间依赖性诱导A549细胞凋亡,其机制可能是通过上调Caspase-3的表达。     

血清锌,铜与铜／锌比值对肺癌诊断,疗效和预后判断的临床价值

本文对60例肺癌和100例健康对照组用原子吸收法测定了血清锌(SZn)、铜(SCu)含量.肺癌组SZn明显低于对照组.SCu与血清铜/锌(SCu/Zn)比值明显高于健康组(P均<0.001).肺癌组按TNM分期,其SCu与SCu/Zn比值各期均较对照组明显增高,且随病期进展而增高,即Ⅳ期>Ⅲ期>Ⅱ期>Ⅰ期.SCu以1.191ppm,SCu/Zn 以1.38为分界,其特异性分别为 87%和88%;敏感性分别为 88.33%和 81.66%.较同期所测血清癌胚抗原(CEA)36.58%和肿瘤DNA聚合酶[DNA—P(CA)]18.18%为高.提示 SCu、SCu/Zn的测定是肺癌辅助诊断、疗效观察及预后判断的辅助指标.     

结直肠癌中C—erbB-2与Ebp1的表达与临床病理特征的关系及其临床意义

目的：研究C—erbB-2与Ebp1蛋白在结直肠癌组织中的表达,并探讨其与结直肠癌临床病理特征的关系及意义。方法：应用免疫组织化学法（EnVision）对65例结直肠癌患者的肿瘤组织及正常结直肠组织分别行C—erbB-2与Ebp1蛋白检测。结果：结直肠癌肿瘤组织中C—erbB-2的表达明显高于正常结直肠组织（P〈0．05）,Ebp1的表达明显低于正常结直肠组织（P〈0．05）;结直肠癌肿瘤组织中C—erbB-2与Ebp1表达与患者年龄、性别以及家族史无关,C—erbB-2的高表达与Ebp1的低表达与肿瘤的TNM分期、分化程度以及淋巴结转移呈正相关（P均〈0．05）;c—erbB-2与Ebp1蛋白表达呈负相关（P〈0．05）。结论：C—erbB-2和Ebp1联合检测有助于对肿瘤转移及预后情况的判断,并为以Ebp1作为生物学靶点的肿瘤免疫治疗研究提供依据。     

The impact of aspirin,statins and ACE-inhibitors on the presentation of colorectal neoplasia in a colorectal cancer screening programme

Background:

There is increasing evidence that aspirin, statins and ACE-inhibitors can reduce the incidence of colorectal cancer. The aim of the present study was to assess the impact of these medications on an individual''s risk of advanced neoplasia in a colorectal cancer screening programme.

Methods:

A prospectively maintained database of the first round of screening in our geographical area was analysed. The outcome measure was advanced neoplasia (cancer or intermediate or high risk adenomata).

Results:

Of the 4188 individuals who underwent colonoscopy following a positive occult blood stool test, colorectal pathology was present in 3043(73%). Of the 3043 patients with colorectal pathology, 1704(56%) had advanced neoplasia. Patients with advanced neoplasia were more likely to be older (OR 1.38; 95% CI 1.19–1.59) and male (OR 1.66; 95% CI 1.43–1.94) (both P<0.001). In contrast, those on aspirin (OR 0.68; 95% CI 0.56–0.83), statins (OR 0.65; 95% CI 0.55–0.78) or ACE inhibitors (OR 0.71; 95% CI 0.57–0.89) were less likely to have advanced neoplasia at colonoscopy (all P<0.05).

Conclusion:

In patients undergoing colonoscopy following a positive occult blood stool test with documented evidence of aspirin, statin or ACE-inhibitor usage, advanced neoplasia is less likely, suggesting that the usage of these medications may have a chemopreventative effect.     

Influence of the Number of Lymph Nodes Examined on the Prognosis of Patients with Dukes'''' B and C Colorectal Carcinoma

OBJECTIVE To analyze the influence of the number of lymph nodes examined on the prognosis of Dukes' B and C colorectal cancer patients.METHODS The relationship between the clinicopathologic features of 373 patients with Dukes' B and C colorectal cancer and number of the lymph nodes examined was retrospectively analyzed.The effect of the different number of nodes examined on the prognosis of the patients was appraised RESULTS The overall mean number of retrieved lymph nodes of the 373 patients with Dukes' B and C colorectal cancer was 13.71±9.38.The site and size of the tumor as well as the depth of tumor infiltration were the major reasons which influenced the number of lymph nodes retrieved.The mean number of lymph nodes examined in the colon-cancer patients was 17.51± 12.79,which was significantly more than the 11.09±6.17(P = 0.000)exam-ined in the rectal-cancer patients.The 5-year survival rate of the patients with Dukes' B large intestinal carcinoma,with fewer lymph nodes retrieved(0 to 10),was only 60.4%,while those with more lymph node retrieved(≥10)had a 5-year survival of 77.5%.So there was a significant difference between the two groups.However the number of lymph nodes examined had no effect on prognosis of the patients with Dukes' C large intestinal carcinoma.Separate analysis of the colon and rectal cancers indicated that to improve the 5-year survival rate,the number of retrieved nodes in cases with rectal cancer should be at least 9,and with colon cancer cases at least 13.CONCLUSION In order to guarantee an accuracy of tumor staging for developing a possible postoperative treatment,at least 9 lymph nodes in rec-tal cancer patients or 13 in colon cancer patients should be harvested.     

阿司匹林对人结肠癌细胞株SW480、HT29中VEGF、β-catenin表达的影响

目的 探讨阿司匹林对人结肠癌细胞株HT-29、SW480生长增殖的影响及其β-catenin、VEGF蛋白和mRNA的表达,并为结直肠癌的预防和治疗提供新的实验和理论依据。方法 采用MTT法检测阿司匹林对SW480、HT-29细胞生长增殖的影响;Real-time PCR和Western blot法检测HT-29、SW480细胞中VEGF、β-catenin mRNA及蛋白的表达情况。结果 在SW480、HT-29细胞的生长增殖过程中,阿司匹林对其有着显著的抑制作用,且具有量效、时效关系;除6 h干预组外,余各组阿司匹林均可抑制VEGF、β-catenin蛋白和mRNA的表达（P＜0.05）。结论 阿司匹林对人结直肠癌细胞株SW480、HT-29的生长增殖具有显著的抑制作用,并对SW480、HT-29中VEGF、β-catenin mRNA和蛋白质的表达具有显著的下调效应;而阿司匹林通过抑制β-catenin的表达,同时调节VEGF抑制肿瘤血管的生成可能是其预防和治疗结直肠癌的作用机制之一。     

Prognostic Factors and the Role of Adjuvant Chemotherapy in Post-curative Surgery for Dukes B and C Colon Cancers and Survival Outcomes: a Malaysian Experience

Background: Adjuvant chemotherapy improves survival in Dukes C colon cancers post-curative resection.However, the evidence for a role with Dukes B lesions remains unproven despite frequent use for diseasecharacterized by poor prognostic features. In view of limited Asia-specific data, this study aimed to determinesurvival outcomes and identify prognostic factors in a tertiary teaching hospital in Malaysia. Materials andMethods: A total of 116 subjects who underwent curative surgery with and without adjuvant chemotherapy forDuke B and C primary colon adenocarcinomas diagnosed from 2004-2009 were recruited and data were collectedretrospectively. Five-year overall survival (OS) and disease free survival (DFS) were analysed using Kaplan-Meiersurvival analysis and log-rank (Mantel-Cox) test. Prognostic factors were determined using Cox proportionalhazards regression with both univariate and multivariate analyses. Results: The survival analysis demonstrateda 5-year OS of 74.0% for all patients, with 74.9% for Dukes C subjects receiving chemotherapy compared to28.6% in those not receiving chemotherapy (p=0.001). For Dukes B disease, the 5-year survival rate was 82.6%compared to 75.0% for subjects receiving and not receiving chemotherapy, respectively (p=0.17). Independentprognostic factors identified included a CEA level more than 3.5 ng/ml (hazard ratio (HR)=4.78; p=0.008),serosal involvement (HR=3.75; p=0.028) and completion of chemotherapy (HR= 0.20; p=0.007). Conclusions:In a regional context, this study supports current evidence from the West that adjuvant chemotherapy improvessurvival in Dukes C colon cancers post curative surgery. However, although a clear benefit has yet to be provenfor Dukes B disease, our results suggest survival improvement in selected cases.     

The effect of aspirin and eicosapentaenoic acid on urinary biomarkers of prostaglandin E2 synthesis and platelet activation in participants of the seAFOod polyp prevention trial

Urinary prostaglandin (PG) E metabolite (PGE-M) and 11-dehydro (d)-thromboxane (TX) B₂ are biomarkers of cyclooxygenase-dependent prostanoid synthesis. We investigated (1) the effect of aspirin 300 mg daily and eicosapentaenoic acid (EPA) 2000 mg daily, alone and in combination, on urinary biomarker levels and, (2) whether urinary biomarker levels predicted colorectal polyp risk, during participation in the seAFOod polyp prevention trial. Urinary PGE-M and 11-d-TXB₂ were measured by liquid chromatography-tandem mass spectrometry. The relationship between urinary biomarker levels and colorectal polyp outcomes was investigated using negative binomial (polyp number) and logistic (% with one or more polyps) regression models. Despite wide temporal variability in PGE-M and 11-d-TXB₂ levels within individuals, both aspirin and, to a lesser extent, EPA decreased levels of both biomarkers (74% [P ≤ .001] and 8% [P ≤ .05] reduction in median 11-d-TXB₂ values, respectively). In the placebo group, a high (quartile [Q] 2-4) baseline 11-d-TXB₂ level predicted increased polyp number (incidence rate ratio [IRR] [95% CI] 2.26 [1.11,4.58]) and risk (odds ratio [95% CI] 3.56 [1.09,11.63]). A low (Q1) on-treatment 11-d-TXB₂ level predicted reduced colorectal polyp number compared to placebo (IRR 0.34 [0.12,0.93] for combination aspirin and EPA treatment) compared to high on-treatment 11-d-TXB₂ values (0.61 [0.34,1.11]). Aspirin and EPA both inhibit PGE-M and 11-d-TXB₂ synthesis in keeping with shared in vivo cyclooxygenase inhibition. Colorectal polyp risk and treatment response prediction by 11-d-TXB₂ is consistent with a role for platelet activation during early colorectal carcinogenesis. The use of urinary 11-d-TXB₂ measurement for a precision approach to colorectal cancer risk prediction and chemoprevention requires prospective evaluation.     

MTHFR C677T polymorphism and colorectal cancer risk in Asians, a meta-analysis of 21 studies

Background: Previous studies concerning the association between methylenetetrahydrofolate reductase(MTHFR) C677T polymorphism and colorectal cancer risk in Asian populations generated conflicting results.A meta-analysis was therefore performed to allow a more reliable estimate of any link. Methods: Relevantstudies concerning the association between the MTHFR C677T polymorphism and risk of colorectal cancer wereincluded into this meta-analysis. The quality of the studies was assessed according to a predefined scale. Oddsratios (ORs) and 95% confidence intervals (CIs) were determined for this gene-disease association using fixedor random effect models according to the heterogeneity between included studies. Results: Finally, 21 studieswith a total of 6692 cases and 8266 controls were included. Meta-analyses showed that there was an obviousassociation of the MTHFR 677T allele with decreased risk of colorectal cancer (OR = 0.91, 95%CI=0.85-0.98,P=0.011). Subgroup analyses by country further identified this association, with dietary folate as the main sourceof heterogeneity. Conclusion: The MTHFR 677T allele is associated with a lower risk of colorectal cancer inAsian populations, and there is effect modification by population plasma folate.     

Synergistic Effects of Valproic Acid and Mitomycin C in Adenocarcinoma Cell Lines and Fresh Tumor Cells of Patients with Colon Cancer

Abstract

Valproic acid has been demonstrated to mediate cytotoxic effects against tumor cells by acting as a histone-deacetylase inhibitor. However, to date, there are only limited data on the effects of valproic acid in colon cancer. Moreover, information regarding combinations of the drug with chemotherapeutic agents is very limited. The latter is of interest as there is increasing evidence for synergism between socalled “molecular targeting drugs” and chemotherapy.

We first demonstrated that valproic acid dose-dependently reduced the viability of adenocarcimona cell lines. After co-incubation with a variety of chemotherapeutic agents, only valproic acid in combination with mitomycin C consistently induced synergistic growth inhibition in all cell lines. To confirm these results in an ex vivo situation, five samples of fresh colon cancer cells were studied. Again, the effect of valproic acid on the viability of the fresh tumor cells was dose dependent. In four of five samples of freshly isolated colon cancer cells, the synergistic effect of valproic acid and mitomycin C on the inhibition of cell growth was confirmed by calculation of the combination index by multiple drug effect analysis.

In conclusion, this is the first demonstration that valproic acid as a model substance for histone-deacetylase inhibitors is effective in tumor cells freshly isolated from patients with colon cancer and that the combination of mitomycin C and valproic acid synergistically decreases viability of colon cancer cells.     

血管内皮生长因子-C与CCR7在大肠癌中的表达

目的　探讨血管内皮生长因子 C和CCR7在大肠癌中的表达及其与淋巴结转移的关系。方法　采用原位杂交和双重免疫组织化学技术,以41例大肠癌和41例癌旁正常大肠黏膜为研究对象,检测VEGF -CmRNA和CCR- 7mRNA的表达情况和微淋巴管密度(LVD )。结果　VEGF CmRNA和CCR -7mRNA在大肠癌组织中阳性表达率分别为3 4.15 % (14 / 41) ,5 8.5 4%(2 4/ 41)。VEGF CmRNA、CCR7mRNA和LVD均与大肠癌淋巴结转移密切相关(P <0 .0 5 )。结论　VEGF CmRNA、CCR7mRNA和LVD与大肠癌的淋巴结转移密切相关,联合检测其在内镜活检组织中的表达有助于预测淋巴结转移的发生。     

Epoxide hydrolase and CYP2C9 polymorphisms, cigarette smoking, and risk of colorectal carcinoma in the Nurses' Health Study and the Physicians' Health Study

Microsomal epoxide hydrolase (mEH) and cytochrome P450 2C9 (CYP2C9) are involved in the bioactivation and detoxification of polycyclic aromatic hydrocarbons (PAHs) derived from tobacco smoke. Two coding-region mEH variants (Tyr113His, His139Arg) and CYP2C9 variants (Arg144Cys, Ile359Leu) have been described and affect enzyme specific activity. We investigated these polymorphisms and tested interactions with smoking in relationship to risk of colorectal carcinoma in two case-control studies nested in the Nurses' Health Study (NHS) and Physicians' Health Study (PHS) cohorts. mEH Tyr113His and His139Arg polymorphisms were not associated with the risk of cancer among 197 incident cases and 490 controls from the NHS. Among 273 incident cases and 453 controls from the PHS, carrying one or two copies of the 'rapid' 139Arg allele was associated with a significantly reduced risk of colorectal cancer (OR=0.70, 95% CI 0.49--0.99) when compared with His139 wild-type individuals. Risk of colorectal cancer was significantly reduced among men carrying the CYP2C9 *1/*2 genotype (OR=0.62, 95% CI 0.42--0.92) or at least one CYP2C9 variant allele (OR=0.72, 95% CI 0.52--1.00) when compared with *1/*1 wild-type individuals. For women, carrying at least one variant CYP2C9 allele was inversely associated with the risk of colorectal cancer (OR=0.85, 95% CI, 0.57--1.27) when compared with *1/*1 wild-type individuals. No statistically significant genotype-smoking or gene-gene interactions were found in this study. Our results indicate that individuals exposed to tobacco carcinogens were at increased risk of colorectal cancer and that overall risk is related to mEH and CYP2C9 genotype, although the results were not consistent between men and women.