Epigenetic modification regulates both expression of tumor-associated genes and cell cycle progressing in human colon cancer cell lines: Colo-320 and SW1116

The aim of this study is to assess the effects of DNA methylation and historic acetylation, alone or in combination, on the expression of several tumor-associated genes and cell cycle progression in two established human colon cancer cell lines: Colo-320 and SW1116. Treatments with 5-aza-2'-deoxycytidine (5-aza-dC) and trichostatin A, alone or in combination, were applied respectively. The methylation status of the CDKN2A promoter was determined by methyla-tion-specific PCR, and the acetylated status of the histones associated with the p21WAF1 and CDKN2A genes was examined by chromatin immunoprecipitation. The expression of the CDKN2A, p21WAF1, p53, p73, APC, c-myc, c-Ki-ras and survivin genes was detected by real-time RT-PCR and RT-PCR. The cell cycle profile was established by flow cytometry. We found that along with the demethylation of the CDKN2A gene promoter in both cell lines induced by 5-aza-dC alone or in combination with TSA, the expression of both CDKN2A and APC genes increased. The treatment of TSA or sodium butyrate up-regulated the transcription of p21WAF1 significantly by inducing the acetylation of histones H4 and H3, but failed to alter the acetylation level of CDKN2A-associated histones. No changes in transcription of p53, p73, c-myc, c-Ki-ras and survivin genes were observed. In addition, TSA or sodium butyrate was shown to arrest cells at the G1 phase. However, 5-aza-dC was not able to affect the cell cycle progression. In conclusion, regulation by epigenetic modification of the transcription of tumor-associated genes and the cell cycle progression in both human colon cancer cell lines Colo-320 and SW1116 is gene-specific.

Molecular analysis and anticancer properties of two identified isolates,Fusarium solani and Emericella nidulans isolated from Wady El-Natron soil in Egypt against Caco-2(ATCC) cell line

Objective:To characterize,identify and investigate the anticancer properties of two new soil fungal isolates,Emericella nidulansand Fusarium solani isolated from Wady El-Natron in Egypt against colon cancer Caco-2(ATCCj cell line.Methods:Soil sample was cultured and two strains were chosen for morphological and phenotypical characterization.Partial sequences of the 18s rRNA gene and the internal transcribed spacer region ITS of the two isolates were amplified by PCR.Phylogenetic tree construction and analysis of the resulted multiple sequences from the two fugal isolates were also carried out.In vitro anticancer activity of the two strains was done against colon Caco-2 cancer cell line.Reverse transcription — PCR was carried out to detect level of expression of p53 in Caco-2 cell line.Results:HF.I displayed morphological and genotypic characteristics most similar to that of Fusarium solani while HF.2 was most similar to Emericella nidulans with high similarity of 99%and 97%respectively.The multiple sequence alignment of the two fungal isolates showed that,the maximum identical conserved domains in the 18s rRNA genes were identified with the nucleotide regions of Slst to 399th base pairs,88th to 525th base pairs respectively.While those in the ITS genes were identified with the nucleotide regions of 88th to 463rd and Slst to 274th.The two isolates showed IC<sub>50 value with（6.24±5.21） and（9.84±0.36） μ g/mL) concentrations respectively at 28h.Reverse transcription- PCR indicated that these cells showed high level of expression for p53 mRNA.Conclusions:The morphology and molecular analysis identified HF.1 and HF.2 to be Fusarium solani and Emericella nidulans;new isolates of anticancer producing fungi from Wady El-Natroon city in Egypt.Treatment with the two isolates caused P53 expression in Caco-2 cell line.These two isolates can be used as an anticancer agents.

Leucine-rich repeat-containing G protein-coupled receptor 5 marks different cancer stem cell compartments in human Caco-2 and LoVo colon cancer lines

BACKGROUND Colon cancer cell lines are widely used for research and for the screening of drugs that specifically target the stem cell compartment of colon cancers.It was reported that colon cancer carcinoma specimens contain a subset of leucine-rich repeatcontaining G protein-coupled receptor 5(LGR5)-expressing stem cells,these socalled“tumour-initiating”cells,reminiscent in their properties of the normal intestinal stem cells(ISCs),may explain the apparent heterogeneity of colon cancer cell lines.Also,colon cancer is initiated by aberrant Wnt signaling in ISCs known to express high levels of LGR5.Furthermore,in vivo reports demonstrate the clonal expansion of intestinal adenomas from a single LGR5-expressing cell.AIM To investigate whether colon cancer cell lines contain cancer stem cells and to characterize these putative cancer stem cells.METHODS A portable fluorescent reporter construct based on a conserved fragment of the LGR5 promoter was used to isolate the cell compartments expressing different levels of LGR5 in two widely used colon cancer cell lines(Caco-2 and LoVo).These cells were then characterized according to their proliferation capacity,gene expression signatures of ISC markers,and their tumorigenic properties in vivo and in vitro.RESULTS The data revealed that the LGR5 reporter can be used to identify and isolate a classical intestinal crypt stem cell-like population from the Caco-2,but not from the LoVo,cell lines,in which the cancer stem cell population is more akin to B lymphoma Moloney murine leukemia virus insertion region 1 homolog(+4 crypt)stem cells.This sub-population within Caco-2 cells exhibits an intestinal cancer stem cell gene expression signature and can both self-renew and generate differentiated LGR5 negative progeny.Our data also show that cells expressing high levels of LGR5/enhanced yellow fluorescent protein(EYFP)from this cell line exhibit tumorigenic-like properties in vivo and in vitro.In contrast,cell compartments of LoVo that are expressing high levels of LGR5/EYFP did not show these stem cell-like properties.Thus,cells that exhibit high levels of LGR5/EYFP expression represent the cancer stem cell compartment of Caco-2 colon cancer cells,but not LoVo cells.CONCLUSION Our findings highlight the presence of a spectrum of different ISC-like compartments in different colon cancer cell lines.Their existence is an important consideration for their screening applications and should be taken into account when interpreting drug screening data.We have generated a portable LGR5-reporter that serves as a valuable tool for the identification and isolation of different colon cancer stem cell populations in colon cancer lines.

Fermented Herbal Decoction Selectively Targeting Human Cancer Cell Line and Human Pathogenic Microorganism

Introduction: Prolonged immuno-suppressed status promised to induce internal growth of malignant cell and infectious agent, yet, only a small part of affected individuals seek medical attention or berried by commercially over-flowed fake information. Several studies have described complementary and alternative medicine as effective strategies for improving anti-infectious agent including malignant cell. The purpose of this study was to investigate the effect of a fermented herbal decoction (FHD) both in vitro and in vivo to malignant cells and microorganism by regulating leukocyte subset proportioning FHD as dietary material. Methods: In this approach of alternative study, selective anti-cancer effect by fermented decoction was tried to show first in vitro system both, cancer cell and virus strain. The fermented herbal decoction consisting of 80 sorts of herbs and fruits. The selective toxicity was set up and then for immunological factors in animal and human. The most important factor is to reduce side effect for a normal cell. Results: First, FHD was proved as safe by animal test. FHD regulated also the proportion of granulocyte and lymphocyte ratio both animal and human. In vitro culture showed selective toxicity by FHD against human melanoma and leukemia cell line but reduced toxicity was showed by normal cell line. As for the anti-virus activity, anti-virus effect was tested on the feeder layer of human fibroblast cell, after 9 days of culture. Second, FHD inhibits colon cancer growth in 3-methylholanthrene induced cancer in rat. Conclusion: The present results suggest that our fermented herbal decoction showed selective anti-cancer activities and anti-virus activities, together with the regulative effect on the immune system.

Growth hormone releasing peptide 2 reverses anorexia associated with chemotherapy with 5-fluoruracil in colon cancer cell-bearing mice

The cancer-associated anorexia-cachexia syndrome is observed in 80% of patients with advanced-stage cancer, and is one of the major obstacles in chemo- therapy. Ghrelin is a orexigenic hormone that has been proposed to prevent anorexia. Aim of the study was to determine whether the addition of the ghrelin agonist growth hormone releasing peptide 2 (GHRP-2) to cytotoxic therapy with 5-fluoruracil (5-FU) prevents the anorexia associated with chemotherapy in cancer cachectic mice. Thirty-three BALB/c female tumourbearing mice were randomized to receive a solution containing: (a) placebo; (b) GHRP-2; (c) 5-FU; or (d) 5-FU + GHRP-2. Ten BALB/c no tumour-bearing mice received placebo solution. Food intake and survival were checked. Six hours after the drug injection the cumulative food intake was signifi cantly increased in mice treated with the combination of 5-FU + GHRP-2 versus the 5-FU alone (P = 0.0096). On day 3, the cumulative food intake of mice treated with GHRP-2,5-FU and 5-FU + GHRP-2 signifi cantly increased com- pared with naive and vehicle groups (P = 0.0007, P = 0.0038 and P = 0.0166, respectively). The median survival time was longer in 5-FU + GHRP-2 treated mice than in those with 5-FU, although it was not signifi cant (18 d versus 15.5 d, P = 0.7). For the fi rst time, we demonstrated that the addition of GHRP-2 to cytotoxic therapy with 5-FU improved appetite in tumour-bearing mice with anorexia/cachexia syndrome in early stage. These data suggest that GHRP-2 may improve the effi cacy of therapy and the quality of life of cancer patients thank to the amelioration of their nutritional state.

Anti-cancer effect of ethylacetate fraction from Orostachys japonicus on HT-29 human colon cancer cells by induction of apoptosis through caspase-dependent signaling pathway

Objective: To investigate the anti-colon cancer effects of ethylacetate fraction from Orostachys japonicus(0. japonicus) on HT-29 cancer cells. Methods: The viability of HT-29 cells was assayed by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H-tetrazolium(MTS) method. Apoptosis induction and cell cycle inhibition were confirmed by fluorescein isothiocyanate and propidium iodide staining using flow cytometry.Morphological changes in the nucleus were observed, using a fluorescence microscope with4',6-diamidino-2-phenylindole(DAPI) nuclear staining. The expression levels of the upstream and downstream proteins involved in the anti-cancer mechanism were confirmed by Western blotting. Results: After treating HT-29 cells with different concentrations of ethylacetate fraction from O. japonicus, the viability of cells decreased in a concentration-dependent manner,while apoptosis induction and apoptotic body formation increased. Cell cycle analysis showed that the arrest occurred at the sub-G_1 and S phase. Among the upstream and downstream proteins involved in anti-cancer activity, the level of B cell lymphoma-2 decreased, and the bcl-2-associated x protein increased. The level of pro-caspase-3, pro-caspase-8, and pro-caspase-9 decreased, while the level of cleaved-caspase-3, cleaved-caspase-8, and cleaved-caspase-9 increased. Moreover, the phosphorylation, that is, activation of extracellular signal regulated kinase 1/2, Jun-N-terminal kinase, and p38 increased. Conclusions: Combining the above results, it is thought that the survival of HT-29 cells is suppressed by ethylacetate fraction from0. japonicus through mitochondrial regulation-induced caspase cascade activation, induction of apoptosis and cell cycle arrest.

Oxidative stress-induced mitochondrial dysfunction in a normal colon epithelial cell line

AIM To determine how a normal human colon cell line reacts to microbial challenge as a way to study oxidative stress-induced responses associated with inflammatory bowel disease.METHODS Normal human colon epithelial cells(ATCC?CRL.1790?)were stimulated with either heat killed E.coli or heat killed murine cecal contents(HKC)and examined for several relevant biomarkers associated with inflammation and oxidative stress including cytokine production,mitochondrial autophagy and oxidant status.TNFα,IL-1βand IL-8 protein concentrations were measured within the supernatants.Fluorescent microscopy was performed to quantify the production of reactive oxygen species(ROS)using an oxidation responsive fluorogenic probe.Mitochondrial morphology and mitochondrial membrane potential was assessed by dual staining using COXIV antibody and a dye concentrating in active mitochondria.Mitochondrial ROS scavenger was used to determine the source of ROS in stimulated cells.Autophagy was detected by staining for the presence of autophagic vesicles.Positive controls for autophagy and ROS/RNS experiments were treated with rapamycin and chloroquine.Mitochondrial morphology,ROS production and autophagy microscopy experiments were analyzed using a custom acquisition and analysis microscopy software(Image J).RESULTS Exposing CRL.1790 cells to microbial challenge stimulated cells to produce several relevant biomarkers associated with inflammation and oxidative stress.Heat killed cecal contents treatment induced a 10-12fold increase in IL-8 production by CRL.1790 cells compared to unstimulated controls at 6 and 12 h(P<0.001).Heat killed E.coli stimulation resulted in a4-5 fold increase in IL-8 compared to the unstimulated control cells at each time point(P<0.001).Both heat killed E.coli and HKC stimulated robust ROS production at 6(P<0.001),and 12 h(P<0.01).Mitochondrial morphologic abnormalities were detected at 6 and12 h based on reduced mitochondrial circularity and decreased mitochondrial membrane potential,P<0.01.Microbial stimulation also induced significant autophagy at 6 and 12 h,P<0.01.Lastly,blocking mitochondrial ROS generation using mitochondrial specific ROS scavenger reversed microbial challenge induced mitochondrial morphologic abnormalities and autophagy.CONCLUSION The findings from this study suggest that CRL.1790cells may be a useful alternative to other colon cancer cell lines in studying the mechanisms of oxidative stress events associated with intestinal inflammatory disorders.

Change in expression of apoptosis genes after hyperthermia,chemotherapy and radiotherapy in human colon cancer transplanted into nude mice

AIM:To investigate the change in expression of p53 ,Bcl-2 ,and Bax genes in human colon cancer cells transplanted into nude mice after hyperthermia,chemotherapy,radiotherapy,thermochemotherapy,thermoradiotherapy and thermochemoradiotherapy. METHODS:Human colon cancer cell line (HT29) was transplanted into the hind limbs of nude mice. Under laboratory simulated conditions of hyperthermia (43℃,60 min),the actual radiation doses and doses of mitomycin C (MMC) were calculated in reference to the clinical radiotherapy for human rectal cancer and chemotherapy prescription for colon cancer. The mice were divided into 6 groups according to the treatment approaches:hyperthermia,chemotherapy,radiotherapy,thermochemotherapy,thermoradiotherapy,and thermochemoradiotherapy. The mice were sacrificed at different time points and the tumor tissue was taken for further procedures. The morphologic changes in membrane,cytoplasm and nuclei of tumor cells of p53,Bcl-2,and Bax after treatment,were observed by immunohistochemistry staining. RESULTS:All of the six treatment modalities down-regulated the expression of p53,Bcl-2 and up-regulated the expression of Bax at different levels. The combined therapy of hyperthermia,with chemotherapy,and/or irradiation showed a greater effect on down-regulating the expression of p53 (0.208 ± 0.009 vs 0.155 ± 0.0115,P < 0.01) and Bcl-2 (0.086 ± 0.010 vs 0.026 ± 0.0170,P < 0.01) and up-regulating Bax expression (0.091 ± 0.0013 vs 0.207 ± 0.027,P < 0.01) compared with any single therapy.CONCLUSION:Hyperthermia enhances the effect of radio-and chemotherapy on tumors by changing the expression of apoptosis genes,such as p53,Bcl-2 and Bax.

Tetrandrine:A Potent Abrogator of G_2 Checkpoint Function in Tumor Cells and Its Mechanism

Objective To assess the ability of tetrandrine （Tet） to enhance the sensitivity to irradiation and its mechanism in cell lines of human breast cancer p53-mutant MCF-7/ADR, p53-wild-type MCF-7 and human colon carcinoma p53-mutant HT-29 as well as in C26 colorectal carcinoma-bearing BALB/c mice. Methods MCF-7/ADR, HT-29 and MCF-7 cells were exposed to irradiation in the absence or presence of tetrandrine. The effect of Tet on the cytotoxicity of X-irradiation in these three cells was determined and the effect of tetrandrine on cell cycle arrest induced by irradiation in its absence or presence was studied by flow cytometry. Moreover, mitotic index measurement determined mitosis of cells to enter mitosis. Western blotting was employed to detect cyclin B1 and Cdc2 proteins in extracts from irradiated or non-irradiated cells of MCF-7/ADR, HT-29 and MCF-7 treated with tetrandrine at various concentrations. Tumor growth delay assay was conducted to determine the radio-sensitization of tetrandrine in vivo. Results Clonogenic assay showed that tetrandrine markedly enhanced the lethal effect of X-rays on p53-mutant MCF-7/ADR and HT-29 cells and the sensitization enhancement ratio （SER） of tetrandrine was 1.51 and 1.63, but its SER was only 1.1 in p53-wt MCF-7 cells. Irradiated p53-mutant MCF-7/ADR and HT-29 cells were only arrested in G2/M phase while MCF-7 cells were arrested in G1 and G2/M phases. Radiation-induced G2 phase arrests were abrogated by tetrandrine in a concentration-dependent manner in MCF-7/ADR and HT-29 cells, whereas redistribution within MCF-7 cell cycle changed slightly. The proportion of cells in M phase increased from 1.3% to 14.7% in MCF-7/ADR cells, and from 1.5% to 13.2% in HT-29 cells, but 2.4% to 7.1% in MCF-7 cells. Furthermore, the levels of cyclin B 1 and Cdc2 expression decreased after X-irradiation in MCF-7/ADR and HT-29 cells, and the mitotic index was also lower. Tet could reverse the decrease and induce the irradiated cells to enter mitosis （M phase）. Endosomatic experiment showed that tetrandrine caused tumor growth delay in irradiated mice. Conclusion Tetrandrine boosts the cell killing activity of irradiation both in vitro and in vivo. Tetrandrine is a potent abrogator for G2 checkpoint control and can sensitize the cells to radiation.

INHIBITORY EFFECT OF DEMO ON THE GROWTH OF TRANSPLANTED HUMAN COLON CANCER IN NUDE MICE

A human colon cancer cell line Hce- 8693 was heterotransplanted in nude mice. Polyamine blosythesis Inhibitor a- dlfiuoromethylomithine (DFMO ) show a marked reproducible inhibition in this model. The size and weight of transplanted tumor In DFMO group were smaller than those of the control group and the average inhibition rate was 72.8% (P < 0.001) . DFMO showed higher tumor inhibitory rate than 5-Fu (35. 4%) (P<0. 001) . Furthermore. DFMO demonstrated less severe bone marrow inhibition in the nude mice than 5-Fu (20. 0% Vs 53. 2%. P<0. 001) .There was no synergistic action in these two drugs at the experimental dose. The concentration of putrescine and spermidine in the plasma and tumor tissue in the DFMO group were 70% lower than those of the control group (P<0. 001) . These results indicate that the anti-tumor effect of DFMO might be explained by the inhibition of polyamine biosynthesis and this study provides an experimental basis for future clinical application of DFMO.

苦参碱抑制大肠癌HT-29细胞环氧化酶-2表达的研究

目的从基因和蛋白水平探讨中药成分苦参碱 (matrine)对大肠癌HT-2 9细胞环氧化酶-2(COX-2 )表达的影响。方法分别采用RT-PCR、Western blot、ELISA等方法检测不同浓度苦参碱处理HT-2 9细胞前后COX-2mRNA、蛋白及其产物前列腺素E2 (PGE2 )水平的改变。结果苦参碱可抑制HT-2 9细胞COX-2mRNA、蛋白表达及PGE2 合成水平 ,但对COX 1无影响。当苦参碱 2 .0mg/ml处理时 ,COX 2mRNA表达在处理后 6h和 9h时抑制率均为 10 0 % ;细胞培养液PGE2 合成水平在 9h时抑制率为6 3.9% ;COX-2蛋白表达在 12h和 2 4h时抑制率分别为 4 8%和 10 0 %。结论苦参碱具有选择抑制HT-2 9细胞COX-2的基因转录、蛋白表达和功能活性等作用 ,在一定浓度和时间范围内 。

二烯丙基二硫对人结肠癌HT-29细胞G_1期的阻滞作用

目的探讨二烯丙基二硫(DADS)对人结肠癌HT-29细胞G1期的阻滞作用及分子机制。方法采用MTT、细胞计数法、流式细胞术和免疫细胞化学方法分析DADS对体外培养的HT-29细胞增殖抑制作用、细胞周期分布及细胞周期相关蛋白表达的影响。结果MTT法显示,60、120μmol.L-1DADS作用HT-29细胞24 h后,生长抑制率分别达23.1%、45.6%。细胞计数法表明,常规培养HT-29细胞群体倍增时间为22.58 h,60μmol.L-1DADS作用HT-29细胞后,其细胞群体倍增时间延长到31.20 h。流式细胞仪分析结果显示,60μmol.L-1DADS阻滞HT-29细胞在G1期,与对照组相比,可使G1期细胞增加约2倍,而120μmol.L-1DADS显著地将细胞阻滞在G2/M期。免疫细胞化学分析表明在G1期阻滞同时有p21W af1蛋白表达上调,Cyc lin E、C-myc蛋白表达下降。结论低剂量DADS对HT-29细胞的抑制增殖作用可能与G1期阻滞有关,DADS对HT-29细胞G1期阻滞的分子机制可能与调节p21W af1、Cyc lin E、C-myc表达相关。

绿茶水提取物诱导体外培养的大肠癌LOVO细胞的凋亡

目的：探讨绿茶水提取物对体外培养的大肠癌ＬｏＶｏ细胞的抑制和诱导细胞发生凋亡的作用。方法：用ＭＴＴ法、琼脂糖凝胶电泳、透射电镜和流式细胞仪的方法，观察绿茶水提取物处理ＬｏＶｏ细胞后其生化和形态学等指标的改变。结果：ＭＴＴ法证实绿茶水提取物对ＬｏＶｏ细胞有抑制作用，抑制率与绿茶水提取物的浓度呈正相关；透射电镜可见ＬｏＶｏ细胞在形态学上出现典型的细胞核固缩、碎裂等凋亡细胞的形态学改变；琼脂糖凝胶电泳呈典型的“梯状（ＤＮＡｌａｄｄｅｒ）”带。流式细胞仪检测结果示：在绿茶水提取物处理ＬｏＶｏ细胞后０～１２ｈＧ１期前无亚二倍体峰出现，而在３６ｈＧ１期前出现一亚二倍体峰，即凋亡峰。结论：绿茶水提取物对大肠癌ＬｏＶｏ细胞有抑制和杀灭作用，而这种作用的机制之一是通过诱导大肠癌细胞发生凋亡，即诱导大肠癌细胞发生凋亡是绿茶杀灭肿瘤细胞的重要机制之一。

螺旋藻藻蓝蛋白对癌激光疗法增敏作用的实验研究

用藻蓝蛋白处理2种癌细胞作体内外激光治癌试验。人大肠癌细胞株HR_(8348)培养后分别用100μg,50μg和25μg的藻蓝蛋白处理,经光波为630nm的铜激光辐照12J/cm^2,用MTT法检测培养癌细胞存活率分别为22.2％,37.6％和89.7％,显示良好的剂量效应。用S_(180)移植瘤小鼠,分别给予藻蓝蛋白注射2mg或口服20mg后,经铜激光辐照瘤体15d后,有效率分别为50％和53％,与对照组比较,具显著差异(P=0.007)。体内外试验证实藻蓝蛋白确具有光敏作用,且其无毒,无副作用,是一种理想的光敏剂。

瘦素对5-氟尿嘧啶损伤结肠癌细胞的影响

目的探讨不同浓度的瘦素对5-氟尿嘧啶(5-FU)损伤结肠癌细胞的影响。方法同时用5-FU及不同浓度的瘦素进行体外干预结肠癌HT-29细胞株。MTT法检测5-FU50%细胞生长抑制率(IC50)的变化。流式细胞仪、原位末端转移酶标记法(TUNEL)进行周期及凋亡分析。以RT-PCR方法检测caspase-9,caspase-3mRNA的表达。结果瘦素抑制5-FU对HT-29的杀伤作用。抑制5-FU诱导的细胞周期阻滞及细胞凋亡。RT-PCR表明加入瘦素后caspase-9,caspase-3mRNA的表达均下降,且呈剂量依赖性。结论瘦素通过下调caspase-9,caspase-3的表达促进结肠癌细胞产生凋亡抵抗,抑制5-FU的损伤作用。

龙葵碱联合VEGF抗体对人结肠癌鸡胚移植模型血管生成的影响

目的建立人结肠癌鸡胚移植模型,探讨龙葵碱、VEGF抗体及两者联合对人结肠癌细胞诱导肿瘤血管生成及肿瘤增殖的影响。方法将人结肠癌HT-29细胞鸡胚移植模型分为实验组和对照组,实验组加入龙葵碱、VEGF抗体和龙葵碱+VEGF抗体混合液,对照组加入磷酸盐缓冲液(PBS)液。通过立体显微镜照相、IPP 6.0图像分析软件分析图片;免疫组织化学方法检测CD34抗原和ki-67抗原,观察龙葵碱、VEGF抗体和龙葵碱联合VEGF抗体对肿瘤血管生成及肿瘤增殖的影响。结果肿瘤血管面积、CD34抗原和ki-67抗原表达:龙葵碱+VEGF抗体组明显优于单药VEGF抗体组和龙葵碱组,VEGF抗体组优于龙葵碱组,3组均明显优于对照组(P<0.01)。结论龙葵碱、VEGF抗体及两者联合时均能抑制人结肠癌HT-29细胞系诱导的肿瘤血管生成及肿瘤增殖,为抗肿瘤血管生成提供了一种新途径。

人参皂苷Rg3对HT-29细胞株MMP-1表达和迁移能力的影响

目的:研究人参皂苷Rg3对结肠癌细胞株HT-29基质金属蛋白酶-1(MMP-1)表达和细胞迁移能力的影响。方法:体外培养HT-29细胞,分为人参皂苷Rg3高剂量组(100μg/mL)、中剂量组(50μg/mL)、低剂量组(25μg/mL)和空白对照组,培养HT-29细胞24、48、72h,RT-PCR法测MMP-1 mRNA表达。利用划痕实验观察Rg3对HT-29细胞迁移能力的影响。结果:24h高剂量组与对照组相比,有显著的统计学差异(P<0.01);48h低、中、高剂量组与对照组相比均有显著的统计学差异(P<0.05、P<0.01、P<0.01);72h低、中、高剂量组与对照组相比均有显著的统计学差异(P<0.01、P<0.01、P<0.01)。划痕实验中空白对照组过河时间为(47.33±2.49)h,低、中、高剂量组过河时间分别为(55.33±2.49)h(P<0.01)、(64.00±1.63)h(P<0.01)和(73.33±1.89)h(P<0.01)。结论:人参皂苷Rg3能抑制HT-29细胞MMP-1的表达和抑制HT-29细胞的迁移能力,并且随着药物浓度的增加及时间的延长,抑制作用增强。

戊地昔布对人结肠癌HT-29细胞凋亡的影响

目的观察戊地昔布(Valdecoxib)对COX-2高表达的人结肠癌HT-29细胞凋亡的影响。方法将体外培养HT-29细胞分为正常组(C)、药物处理组(V)及溶剂对照组(S)。采用流式细胞术检测细胞凋亡,Western blot检测COX-2、caspase-3、cleaved caspase-3、Bcl-2、p38 MAPK、p-p38MAPK。结果与正常组相比,药物处理组细胞凋亡明显增加(P<0.05),cleaved caspase-3和p-p38MAPK表达增高,Bax/Bcl-2比率明显升高(P<0.05)。Valdecoxib干预能够显著促进HT-29细胞凋亡,上调cleaved caspase-3和p-p38 MAPK的表达,增加Bax/Bcl-2比率。结论 COX-2选择性抑制剂Valdecoxib能够促进HT-29细胞凋亡部分可能是通过激活p38MAPK信号通路而实现的。

防己诺林碱对结肠癌细胞恶性生物学行为及HIF-1α/VEGF/Akt通路的相关性研究

目的:研究防己诺林碱(FAN)对结肠癌的作用以及与缺氧诱导因子1α(HIF-1α)/血管内皮生长因子(VEGF)/蛋白激酶B(Akt)通路的相关性。方法:用5、10、20μg/ml的防己诺林碱分别处理结肠癌细胞HT-29 48 h,克隆形成实验检测细胞生长,蛋白印迹检测增殖标记蛋白Ki67、增殖细胞核抗原(PCNA)、上皮细胞钙黏蛋白(E-cadherin)、神经细胞钙黏蛋白(N-cadherin)、HIF-1α、VEGF和Akt的表达,Transwell检测细胞侵袭情况,显微镜观察上皮向间质的形态转变;采用皮下注射结肠癌细胞HT-29构建移植瘤模型,腹腔分别注射5、10、20μg/ml防己诺林碱,检测结肠癌移植瘤体积,免疫组化检测Ki67和VEGF,蛋白印迹检测HIF-1α、VEGF、Akt的表达,HE染色观察肝肾损伤。结果:与Blank cells相比较,FAN组的结肠癌细胞HT-29克隆形成率显著降低,Ki67和PCNA的表达量显著下调,侵袭细胞数目显著减少,VEGF和N-cadherin表达量显著下调,E-cadherin表达量显著上调,HIF-1α、VEGF和Akt表达量显著下调;与Blank组相比,FAN组的移植瘤体积明显小,Ki67和VEGF阳性比率显著降低,HIF-1α、VEGF和Akt表达量显著下调,肝肾无损伤。结论:防己诺林碱都可以抑制结肠癌细胞HT-29的生长和增殖、侵袭能力、上皮间质转化,并且抑制结肠癌细胞HIF-1α/VEGF/Akt信号通路,从而抑制结肠癌的发生和发展。

大蒜素对人结肠癌HT29细胞增殖影响及作用机制研究

目的:探讨大蒜素对体外培养结肠癌HT29细胞增殖的影响,并探讨其作用机制。方法:采用四甲基偶氮唑蓝(MTT)法测定不同浓度大蒜素对HT29细胞增殖抑制率;流式细胞术测定细胞周期变化及凋亡相关蛋白Bcl-2与Bax的表达。结果:MTT显示大蒜素能抑制人结肠癌HT29细胞的增殖,并具有时间-剂量依赖性;流式细胞术测定结果显示10μg/ml大蒜素可明显诱导HT29细胞凋亡,并将细胞周期阻滞在G2/M期;可降低癌基因蛋白Bcl表达,而促进Bax表达。结论:大蒜素对人结肠癌HT29细胞增殖具有抑制作用,可能与细胞周期阻滞和凋亡相关蛋白表达有关。