Molecular mechanisms of denbinobin-induced anti-tumorigenesis effect in colon cancer cells

AIM: To explore both the in vitro and in vivo effects of denbinobin against colon cancer cells and clarify its underlying signal pathways. METHODS: We used COLO 205 cancer cell lines and nude mice xenograft model to study the in vitro and in vivo anti-cancer effects of denbinobin. RESULTS: Denbinobin at concentration of 10-20 μmol/L dose-dependently suppressed COLO 205 cell proliferation by MTT test. Flow cytometry analysis and DNA fragmentation assay revealed that 10-20 μmol/L denbinobin treatment induced COLO 205 cells apoptosis. Western blot analysis showed that caspases 3,8,9 and Bid protein were activated by denbinobin treatment to COLO 205 cells accompanied with cytochrome c and apoptosis-inducing factor (AIF) translocation. Pretreatment of MEK 1 inhibitor (U10126), but not p38 inhibitor (SB203580) and JNK inhibitor (SP600125), reversed denbinobin-induced caspase 8, 9 and Bid activation in COLO 205 cells suggesting that extracellular signal-regulated kinase were involved in the denbinobin-induced apoptosis in COLO 205 cells. Significant regression of tumor up to 68% was further demonstrated in vivo by treating nude mice bearing COLO 205 tumor xenografts with denbinobin 50 mg/kg intraperitoneally. CONCLUSION: Our findings suggest that denbinobin could inhibit colon cancer growth both in vitro and in vivo. Activation of extrinsic and intrinsic apoptotic pathways and AIF were involved in the denbinobin-induced COLO 205 cell apoptosis.     

IQGAP2抑制结肠癌细胞侵袭且通过启动子异常甲基化致基因沉默

目的 探讨在结肠癌细胞系中,含IQ模序GTP酶激活蛋白(IQGAP)2的启动子甲基化状态及IQGAP2对结肠癌细胞侵袭的影响.方法 在人结肠癌RKO细胞株中,采用实时荧光定量聚合酶链反应(RT-PCR)、脱甲基化试剂5-aza-2'-deoxycytidine处理,甲基化特异性聚合酶链反应(MSP)法、甲基化测序检测I...     

Mechanisms linking obesity,inflammation and altered metabolism to colon carcinogenesis

Due to its prevalence, obesity is now considered a global epidemic. It is linked to increased risk of colorectal cancer, the third most common cancer and the second leading cause of death among adults in Western countries. Obese adipose tissue differs from lean adipose tissue in its immunogenic profile, body fat distribution and metabolic profile. Obese adipose tissue releases free fatty acids, adipokines and many pro‐inflammatory chemokines. These factors are known to play a key role in regulating malignant transformation and cancer progression. Obese adipose tissue is infiltrated by macrophages that participate in inflammatory pathways activated within the tissue. Adipose tissue macrophages consist of two different phenotypes. M1 macrophages reside in obese adipose tissue and produce pro‐inflammatory cytokines, and M2 macrophages reside in lean adipose tissue and produce anti‐inflammatory cytokines, such as interleukin‐10 (IL‐10). The metabolic networks that confer tumour cells with their oncogenic properties, such as increased proliferation and the ability to avoid apoptosis are still not well understood. We review the interactions between adipocytes and immune cells that may alter the metabolism towards promotion of colorectal cancer.     

肺部慢性炎症与肺癌相关性的研究进展

与癌症相关的炎症已经被认为是“肿瘤的第7种生物学特征”.研究表明,许多肺部慢性炎症性疾病均与肺癌的发生、发展密切相关.其中,慢性炎症引起的氧化应激、免疫抑制微环境的形成能够引起相关信号通路的异常,导致原癌基因激活或抑癌基因失活,进而促进肺癌的发生、发展.本文将讨论COPD、特发性肺纤维化和肺结核这几种常见的肺部慢性炎症与肺癌的相关性,并探讨它们是如何通过慢性炎症促进肺癌的发生、发展.     

逆转录病毒载体介导IL-6基因修饰大肠癌细胞的抗瘤效应

目的:将外源性 IL-6基因导入大肠癌细胞,建立 IL-6基因表达株,观察 IL-6转基因表达对大肠癌细胞的体内外抑制作用.方法:参照分子克隆技术将构建成功的重组逆转录病毒载体 pZIPIL-6cDNA 转染 PA317包装细胞,以 G418筛选抗性细胞,常规制备重组病毒液并感染大肠癌 HT-29细胞,采用 Northern Blot 分析基因转录水平,ELISA 法和 MTT 显色法检测蛋白表达的量与活性,以细胞生长曲线和集落形成实验以及裸鼠移植瘤实验观察转导株的体内外抑瘤作用。结果:制备了高滴度的重组病毒液(5.1×10~5cfu/ml),建立了稳定表达 IL-6的转导细胞(HT-29IL-6),表达的量与活性分别为1132.5pg/ml/10~5cells 24h 与150U/ml,转导株的细胞群体倍增时间为2.5天,对数生长期在4～7天之间,集落形成率和抑制率分别是2.21%和50%,接种裸鼠皮下的出瘤时间为13.5天,最终瘤体直径在6.5～8.5mm之间,移植瘤标本镜下可见大量凋亡细胞,以上结果与非转导株 HT-29细胞相比,均有显著差异。结论:通过逆转录病毒载体的介导,IL-6基因能稳定整合在靶细胞染色体并进行有效的转录表达,IL-6转基因表达可明显抑制大肠癌细胞的体外增殖和体内移植瘤的形成与发展。     

Therapeutic implications of colon cancer stem cells

Colorectal cancer is the second most common cause of cancer-related death in many industrialized countries and is characterized by a heterogenic pool of cells with distinct differentiation patterns. Recently, the concept that cancer might arise from a rare population of cells with stem cell-like properties has received support with regard to several solid tumors, including colorectal cancer. According to the cancer stem cell hypothesis, cancer can be considered a disease in which mutations either convert no...     

MDM2与P14ARF在结肠肿瘤中的表达及意义

目的 探讨MDM2和P14ARF（alternative reading frame)在人结肠癌组织中的表达及其意义。方法 用免疫组织化学方法检测36例癌旁正常结肠组织，28例结肠腺瘤及42例结肠癌中二者的表达及其与组织分化程度的关系。结果 MDM2、P14ARF在癌旁正常结肠组织，结肠腺瘤，结肠腺癌中的阳性表达率分别为0、0、21．4％和100％、82．14％、80．95％。MDM2在结肠腺癌中的表达率明显高于癌旁正常结肠组织及腺瘤组织（P＜0．05），P14ARF在结肠腺瘤和结肠腺癌中的表达率均明显低于癌旁正常结肠组织（P＜0．05）。MDM2和P14ARF在不同分化程度结肠癌中的表达率分别为11．1％，24．0％，25．0％和88．9％、92．0％、37．5％。MDM2在不同分化程度结肠癌中的表达无明显差异（P＞0．05），而P14ARF在低分化结肠癌中的表达明显低于高分化和中等分化的结肠癌（P＜0．05）。结论 MDM2和P14ARF在人结肠癌中的表达异常可能与结肠癌的发生发展有关。     

HT29和HCT116结肠癌细胞无血清培养形成肿瘤干细胞球特性的差异性研究

目的比较HT29和HCT116两种结肠癌细胞系中肿瘤干细胞的差异,初步探讨结肠癌干细胞研究模型。方法以无血清培养法培养HT29和HCT116细胞,观察其在不同时间形成肿瘤干细胞球的差异,用限制性稀释法计算两者的成球率;流式细胞术分析HT29和HCT116细胞系中CD44／CD24的表达情况;裸鼠体内成瘤实验鉴定HT29细胞球与HCT116细胞球成瘤能力。结果无血清培养法发现HCT116较HT29更易形成肿瘤干细胞球且所需时间更短,即HT29在无血清培养的第7天开始形成规则的球体,而HCT116则在第5天就已形成规则的球体,HCT116成球率（11．4±1．15）％高于HT29（3．31±0．27）％,且差异有统计学意义（P〈0．05）;HT29和HCT116中CD44±／CD24±各细胞含量有显著差异,结果显示具有干细胞特性的CD44＋／CD24＋结肠癌细胞在HCT116中所占比例（60．33±5．75）％明显高于HT29（9．23±2．15）％,差异有统计学意义（t=13．939,P〈0．05）;体内成瘤实验发现HCT116细胞球在裸鼠体内的成瘤能力明显强于HT29细胞球,HCT116细胞球的成瘤速度及瘤体生长速度都较HT29细胞球快。结论与HT29相比,HCT116结肠癌细胞系更适合作为肿瘤干细胞研究的模型。     

miR-140靶向调控SOX2在结肠癌中的作用机制研究

目的 分析miR-140在结肠癌中的作用机制.方法 qRT-PCR检测miR-140在结肠癌细胞和组织中的表达;CCK8法、细胞划痕实验检测miR-140对结肠癌HT29细胞增殖和迁移的影响.TargetScan筛选miR-140的潜在靶基因并通过双荧光素酶报告基因试验进行验证;采用qRT-PCR和Western bl...     

西咪替丁抑制人肠癌裸鼠移植瘤

目的：研究西咪替丁对人结肠癌裸鼠移植瘤生长的抑制作用及机制。方法：建立人结肠癌裸鼠皮下移植瘤模型。随机分2组,每组5只实验鼠。肿瘤种植前3 d开始分别皮下注射生理盐水(对照组)或西咪替丁(治疗组),每天1次,观察成瘤时间及瘤体成长情况。肿瘤种植后第7周处死实验鼠,测定瘤体大小,并用免疫组化方法测定肿瘤组织内微血管密度(MVD)和血管内皮生长因子(VEGF)的表达。结果：治疗组肿瘤体积明显小于对照组;治疗组肿瘤组织中的VEGF表达程度和MVD计数亦明显低于对照组。结论：西咪替丁通过抑制VEGF表达,减少血管生成,从而抑制肿瘤生长。     

粪便钙卫蛋白检测在结肠息肉中的应用价值

结肠癌是一个很重要的健康问题,在全球有很高的发病率。结肠息肉是结肠癌的一种癌前病变,尤其是腺瘤性息肉,因此提高对结肠息肉的诊治水平,可以降低结肠癌的发生。钙卫蛋白作为急性炎性细胞活化的标志物,目前已有大量研究证实粪钙卫蛋白在胃肠道炎症性病变中高表达,特别是对炎症性肠病的病情活动评估及预测复发等方面已有较明确结论。结肠息肉作为肠道炎症病变的结果,也有研究证实结肠息肉患者粪便中钙卫蛋白水平是升高的,现综述如下。     

New insights into calcium, dairy and colon cancer

This paper is to review recent information about the relationship of calcium and dairy foods to colon cancer. The review focuses on primary prevention, discusses the potential components in dairy foods that might be anti-neoplastic, reviews the epidemiologic information and describes intervention studies demonstrating efficacy of calcium and vitamin D in reducing colorectal polyp recurrence. Since vitamin D is important in cancer prevention, pertinent data is discussed and potential mechanisms of actions presented. Calcium and vitamin D are important agents for the primary prevention of colorectal neoplasia.     

不伴贫血结肠癌患者的临床特征

目的探讨不伴贫血的结肠癌患者的诊断和临床特征。方法收集本院2007年1月~2009年6月期间确诊的结肠癌病例,以贫血结肠癌患者作为对照,对不伴贫血结肠癌患者的临床特点进行研究和分析。结果不伴贫血的结肠癌患者发病年龄主要在40~70岁之间;以左半结肠病变多见,构成比为58.8%(20/34);Dukes分期较早,A期占47.0%;组织学分型以腺癌为主,其中又以乳头状腺癌多见;病程大多在半年以内;临床症状与对照组相比无特异性,结肠镜为其主要的诊断手段。结论不伴贫血的结肠癌患者多为左半结肠癌病变,病程相对较短,诊断主要依靠结肠镜。     

Diet and epigenetics in colon cancer

Over the past few years, evidence has accumulated indicating that apart from genetic alterations, epigenetic alterations, through e.g. aberrant promoter methylation, play a major role in the initiation and progression of colorectal cancer （CRC）. Even in the hereditary colon cancer syndromes, in which the susceptibility is inherited dominantly, cancer develops only as the result of the progressive accumulation of genetic and epigenetic alterations. Diet can both prevent and induce colon carcinogenesis, for instance, through epigenetic changes, which regulate the homeostasis of the intestinal mucosa. Food-derived compounds are constantly present in the intestine and may shift cellular balance toward harmful outcomes, such as increased susceptibility to mutations. There is strong evidence that a major component of cancer risk may involve epigenetic changes in normal cells that increase the probability of cancer after genetic mutation. The recognition of epigenetic changes as a driving force in colorectal neoplasia would open new areas of research in disease epidemiology, risk assessment, and treatment, especially in mutation carriers who already have an inherited predisposition to cancer.     

Reversal of defective lymphoproliferation in postoperative patients with colon cancer

Summary To establish a method for evaluation of immunological parameters in small blood samples, a whole blood technique was developed for the estimation of mitogen- or antigen-induced proliferation. Studies regarding cellular immunity in patients with colon cancer were done with 108 patients in all tumor stages, aged 32 to 80 years. They were studied before surgery and 10 days after operation. A group of 35 patients were further tested 3 months after surgical treatment. In patients with colon cancer the proliferative responses of peripheral blood lymphocytes to mitogens were significantly lower in comparison to healthy controls. These results were found when the response to concanavalin A, phytohemagglutinin, OKT 3, and pokeweed mitogen were analyzed preoperatively and 10 days postoperatively. There was no relation to the stage of disease. The marked reduction of mitogen responses was followed by a gradual return toward normal values 3 months after surgical resection of neoplastic growth in 80% of the patients. Our studies indicate that the defects were largely restored when testing was performed 3 months after operation. Using this result, it will be possible to perform longterm studies in order to establish if there is a correlation between the return to normal immune reactivity and the survival of individual patients.Dedicated to Professor Dr. E. Hecker on the occasion of his 60th birthday     

New paradigms in chronic intestinal inflammation and colon cancer: role of melatonin

In intestinal bowel disease (IBD), immune-mediated conditions exert their effects through various cells and proinflammatory mediators. Recent data support a participation of the endoplasmic reticulum stress and mitochondrial dysfunctions in IBD. Moreover, it is evident that chronic degenerative pathologies, including IBD, share comparable disease mechanisms with alteration in the autophagy mechanisms. Chronic inflammation in IBD exposes these patients to a number of signals known to have tumorigenic effects. This circuitry of inflammation and cancer modifies apoptosis and autophagy, and promotes cellular cycle progression, invasion, and angiogenesis. Melatonin has been shown as a specific antioxidant reducing oxidative damage in both lipid and aqueous cell environments. However, several studies provide further insight into the molecular mechanisms of melatonin action in the colon. In this line, recent data suggest that melatonin modulates autophagy and sirtuin activity. An anti-autophagic property of melatonin has been demonstrated, and it could contribute to its anti-oncogenic activity. Nevertheless, there is no information about whether antitumoral effects of melatonin on colon cancer are dependent on autophagy. Sirtuins have pleiotropic effects on cancer development, being reported both as facilitator and as suppressor of colon cancer development. Sirtuins and melatonin are connected through the circadian clock machinery, and melatonin seems able to correct the alterations in sirtuin activity associated with several pathological conditions. Autophagy and sirtuin activities are linked through 5'AMP-activated protein kinase (AMPK) activation, which switches on autophagy and increases sirtuin. The effect of melatonin on AMPK and the impact of this effect on IBD and colon cancer remain an open question.     

Early stage colon cancer

Evidence has now accumulated that colonoscopy and removal of polyps,especially during screening and surveillance programs,is effective in overall risk reduction for colon cancer.After resection of malignant pedunculated colon polyps or early stage colon cancers,long-term repeated surveillance programs can also lead to detection and removal of asymptomatic high risk advanced adenomas and new early stage metachronous cancers.Early stage colon cancer can be defined as disease that appears to have been completely resected with no subsequent evidence of involvement of adjacent organs,lymph nodes or distant sites.This differs from the clinical setting of an apparent"curative"resection later pathologically upstaged following detection of malignant cells extending into adjacent organs,peritoneum,lymph nodes or other distant sites,including liver.This highly selected early stage colon cancer group remains at high risk for subsequent colon polyps and metachronous colon cancer.Precise staging is important,not only for assessing the need for adjuvant chemotherapy,but also for patient selection for continued surveillance.With advanced stages of colon cancer and a more guarded outlook,repeated surveillance should be limited.In future,novel imaging technologies(e.g.,confocal endomicroscopy),coupled with increased pathological recognition of high risk markers for lymph node involvement(e.g.,"tumor budding")should lead to improved staging and clinical care.     

No association between phosphatase and tensin homolog genetic polymorphisms and colon cancer

AIM： To investigate the association between single nucleotide polymorphisms （SNPs） in the phosphatase and tensin homolog （PTEN） tumor suppressor gene and risk of colon cancer.
METHODS： We utilized a population-based casecontrol study of incident colon cancer individuals （n= 421） and controls （n = 483） aged ≥ 30 years to conduct a comprehensive tagSNP association analysis of the PTEN gene.
RESULTS： None of the PTEN SNPs were statistically significantly associated with colon cancer when controlled for age, gender, and race, or when additionally adjusted for other known risk factors （P 〉 0.05）. Haplotype analyses similarly showed no association between the PTEN gene and colon cancer.
CONCLUSION： Our study does not support PTEN as a colon cancer susceptibility gene.     

Expression of aldehyde dehydrogenase 1 in colon cancer

ObjectiveTo study the expression of ALDH1 in colon cancer and its clinical significance.MethodsThe expression of ALDH1 was examined in 98 surgical specimens of primary colonic carcinoma and 15 normal colon tissues with immunohistochemistry method. The correlations of the expression with clinicopathological parameters and prognosis of colon cancer were analyzed.ResultsThe positive rate of expression of ALDH1 was 76.5% (75/98) in the cancer tissues and 13.3% (2/15) in normal colon tissues. There were an obvious statistical difference (P<0.05) between the two groups. The ALDH1 expression was significantly correlated with the histological grade, TNM stages and lymph node metastasis in colon cancer (P<0.05). It was also related with patients' survival time, those with positive expressions had a poor prognosis (P<0.05).ConclusionsThe results suggeste that the overexpression of ALDH1 plays important roles in proliferation and progression in colon cancer, the ALDH1 may be a valuable marker to predict the biological behavior and trend of metastasis of colon cancer.