published_or_final_version / Surgery / Master / Master of Philosophy

Kong Ka-lai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 126-149). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / Abstract (Chinese Version) --- p.vi / Table of Contents --- p.ix / List of Figures/Table --- p.xiii / List of Abbreviations --- p.xvi / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- An Overview on Cancer --- p.1 / Chapter 1.2 --- Biological Effects of Chlorophyllin --- p.7 / Chapter 1.2.1 --- CHL as Photosensitizer --- p.7 / Chapter 1.2.2 --- CHL as Antioxidant --- p.8 / Chapter 1.2.3 --- CHL as Anticarcinogenic Agent --- p.9 / Chapter 1.3 --- Regulation of Cell Cycle --- p.13 / Chapter 1.3.1 --- Cell-Cycle Checkpoints --- p.13 / Chapter 1.3.2 --- Cell-Cycle Regulatory Proteins --- p.15 / Chapter 1.4 --- Regulation of Mitogen-Activated Protein Kinase (MAPK) Signaling Cascade --- p.21 / Chapter 1.5 --- Programmed Cell Death (or Apoptosis) --- p.27 / Chapter 1.5.1 --- Regulation of Caspase-Dependent Apoptosis --- p.28 / Chapter 1.5.2 --- Regulation of Caspase-Independent Cell Death --- p.32 / Chapter 1.5.3 --- Bcl-2 Family Proteins in Modulation of Cell Death --- p.32 / Chapter 1.6 --- In Vivo Antitumor Screening System --- p.37 / Chapter 1.7 --- Aims of the Present Study --- p.38 / Chapter Chapter 2 --- In Vitro Studies of the Anticancer Effect of Chlorophyllin / Chapter 2.1 --- Introduction --- p.39 / Chapter 2.1.1 --- DNA-Flow Cytometric Analysis --- p.51 / Chapter 2.1.2 --- Western Blot Analysis --- p.54 / Chapter 2.2 --- Materials and Methods --- p.56 / Chapter 2.2.1 --- Maintenance of Cell Lines --- p.56 / Chapter 2.2.2 --- Cytotoxic and Cytostatic Effects on the Cancer Cells --- p.56 / Chapter 2.2.3 --- DNA-Flow Cytometric Analysis --- p.60 / Chapter 2.2.4 --- Western Blot Analysis --- p.61 / Chapter 2.2.5 --- JC-1 Mitochondrial Potential Sensor --- p.64 / Chapter 2.2.6 --- Caspase Inhibitors --- p.65 / Chapter 2.2.7 --- Statistical Analysis --- p.66 / Chapter 2.2.8 --- Densitometric Analysis --- p.66 / Chapter 2.3 --- Results --- p.67 / Chapter 2.3.1 --- Effects of CHL on the Growth of Human Cancer Cells by MTT Assay --- p.67 / Chapter 2.3.2 --- Effect of CHL on the Proliferation of MCF-7 Cells by Chemi-BrdU Incorporation --- p.69 / Chapter 2.3.3 --- Effect of CHL on Cell Cycle of MCF-7 Cells --- p.71 / Chapter 2.3.4 --- Effect of CHL on the Cyclin D1 Expression in MCF-7 Cells --- p.74 / Chapter 2.3.5 --- Effects of CHL on JNK and c-Jun Expressions and Their Phosphorylations in MCF-7 Cells --- p.76 / Chapter 2.3.6 --- Effect of CHL on DNA fragmentation in MCF-7 Cells --- p.78 / Chapter 2.3.7 --- Effect of CHL on Mitochondrial Membrane Potential of MCF-7 Cells --- p.80 / Chapter 2.3.8 --- Effects of CHL on the PARP Expression and Cleavage in MCF-7 Cells --- p.83 / Chapter 2.3.9 --- "Effects of CHL on Bcl-2, Bcl-xL and Bad Expressions in MCF-7 Cells" --- p.85 / Chapter 2.3.10 --- Effects of CHL on Caspase Activations in MCF-7 Cells --- p.88 / Chapter 2.3.11 --- Effects of Caspase Inhibitors on the CHL-Induced Apoptosis in MCF-7 Cells --- p.90 / Chapter 2.4 --- Discussion --- p.93 / Chapter Chapter 3 --- In Vivo Studies of the Anticancer Effect of Chlorophyllin / Chapter 3.1 --- Introduction --- p.104 / Chapter 3.2 --- Materials and Methods --- p.106 / Chapter 3.2.1 --- Transplantation of MCF-7 Cells into the Nude Mice and Treatment --- p.106 / Chapter 3.2.2 --- Western Blot Analysis --- p.107 / Chapter 3.2.3 --- Statistical Analysis --- p.107 / Chapter 3.3 --- Results --- p.108 / Chapter 3.3.1 --- In Vivo Antitumor Activity of CHL --- p.108 / Chapter 3.3.2 --- In Vivo Effects of CHL on Cyclin D1 and Bcl-2 Expressions in MCF-7 Solid Tumor --- p.111 / Chapter 3.4 --- Discussion --- p.113 / Chapter Chapter 4 --- General Discussion --- p.115 / References --- p.126

Chlorophyllin (CHL), a water-soluble derivative of the green plant pigment, chlorophyll, is an effective antimutagen and anticarcinogen in various model systems when used as a modulator against a class of carcinogens that, in general, have a structure consisting of at least three fused rings. Dibenzo[a,l]pyrene (DBP), an extremely potent environmental carcinogen, has been isolated from urban air samples, tobacco smoke, and coal smoke condensate. A study was conducted to evaluate the complex interrelationships among dietary DBP doses with co-exposure to a range of CHL doses. In order to achieve adequate statistical power in the generation of multiple dose-response curves, this dose-dose matrix experiment utilized over 12,000 rainbow trout. The resulting DNA adducts were assessed and evaluated as biomarkers of exposure to discern their relationship with the final tumor outcome. CHL was highly effective in reducing DBP-initiated DNA adduct formation in the liver and stomach and strongly inhibited tumor formation in the liver (56-79% inhibition), stomach (30-68%), and swim bladder (over 80% at the highest DBP dose). Molecular dosimetry revealed adduct formation to be predictive of final tumor response in both organs regardless of CHL dose. Other parameters evaluated were consistent with CHL-mediated protection. A clinical CHL preparation, evaluated in a human population subsequent to the seminal demonstration of CHL chemopreventive properties against AFB��� in trout (1), revealed CHL to be just as effective in reducing biomarkers of alfatoxin exposure to humans (2). Dietary administration of this clinical preparation along with DBP in the rainbow trout demonstrated CHL protective capacity against DBP-initiated multi-organ DNA adduct formation and final tumor incidence. Sucrose was evaluated, deemed unlikely to be sequestered in a complex with CHL, and was used as a control in a pharmacokinetic study evaluating the biodistribution of DBP with and without CHL. The results provide evidence against a non-specific masking mechanism for CHL-mediated blocking of DBP (or aflatoxin)-initiated tumorigenesis. CHL at multiple doses provided significant protection against multi-dose DBP-initiated DNA adduction and tumor formation in multiple organs. CHL-mediated protection, primarily by reduced carcinogen biouptake and consistent with a complexation mechanism, is supported by these results. / Graduation date: 2003

published_or_final_version / Anatomy / Master / Master of Philosophy

Made available in DSpace on 2014-06-11T19:32:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-04-26Bitstream added on 2014-06-13T20:42:44Z : No. of bitstreams: 1 morais_mcc_dr_arafcf.pdf: 1408212 bytes, checksum: c1d67dd20ca622443f0331dff47792b5 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Universidade Estadual Paulista (UNESP) / A quimioprevenção do câncer é definida como o uso de produtos naturais ou sintéticos para atrasar, bloquear ou reverter o processo de carcinogênese. Produtos naturais apresentam uma diversidade de estruturas químicas que servem de modelo para o desenvolvimento de novos princípios ativos antitumorais e quimiopreventivos. Alcaloides guanidínicos presentes nas folhas de Pterogyne nitens apresentam atividade antitumoral e foram selecionados para os ensaios. O ácido gálico foi escolhido como modelo e seus derivados tiveram atividade quimiopreventiva descrita por ser produto natural antioxidante presente nas folhas de Alchornea glandulosa. Uma coleção de 70 substâncias foi classificada em 6 grupos de acordo com sua estrutura. Derivados de ácidos fenólicos, alcaloides guanidínicos, fenamatos, carvonas, xantonas, flavonas e chalconas preniladas foram avaliadas em ensaios de citotoxicidade por SRB em células MCF-7 e MDA-MB-231, e a atividade quimiopreventiva por meio de indução da enzima quinona-redutase (NQO1) em células Hepa 1c1c7, inibição in vitro de aromatase (CYP19), inibição de NF-κB ativado por TNFα e inibição da produção de NO em células RAW 264.7 estimuladas por LPS. Além disso, alcaloides guanidínicos nitensidina A (NTA), nitensidina B (NTB) e nitensidina T (NTT) foram avaliados pelo ensaio de MTT e a indução de apoptose por coloração com Hoechst 33342 e iodeto de propídio, ambos em células HepG2. A genotoxicidade do ácido gálico (GA) e galato de metila (G1) foi avaliada em células HepG2 pelo ensaio do cometa. GA e G1 apresentaram inibição de NF-κB (CI50 = 19,8 μM e 12,1 μM, respectivamente), sendo que GA provocou quebras de DNA significantes (P < 0,05) nas concentrações de 12 μM e 40 μM verificados pelo ensaio do cometa. Galato de propila (G3) e galato de butila... / Cancer chemoprevention is defined as the use of natural or synthetic products to delay, block or reverse the carcinogenesis process. Natural products presents a diversity of chemical structures that serve as template for the development of new active antitumor and chemopreventive agents. Guanidine alkaloids from the leaves of Pterogyne nitens have antitumor activity and were selected for the assays. Gallic acid, an antioxidant natural product present in the leaves of Alchornea glandulosa, was selected as template and its derivatives chemopreventive activity is reported. A collection of 70 compounds were classified into six groups according to their structure. Phenolic acid derivatives, guanidine alkaloids, fenamates, carvones, xanthones, prenylated flavones and chalcones were evaluated in cytotoxicity assays through SRB in MCF-7 and MDA-MB-231 cell lines, and chemopreventive activity by means of quinone-reductase (NQO1) induction in Hepa 1c1c7 cell line, in vitro aromatase (CYP19) inhibition, TNFα-activated NF-κB inhibition and NO production in LPS-stimulated RAW 264.7 cells. Guanidine alkaloids nitensidine A (NTA), nitensidine B (NTB) and nitensidine T (NTT) were evaluated through MTT assay and apoptosis induction with Hoechst 33342 and propidium iodide stain, both in HepG2 cell line. Genotoxicity of gallic acid (GA) and methyl gallate (G1) was evaluated in HepG2 cells by the comet assay. GA and G1 presented NF-κB inhibition (IC50 = 19.8 μM and 12.1 μM, respectively), and it resulted in significant (P < 0.05) DNA strand breaks at 12 μM and 40 μM as verified by the comet assay. Propyl gallate (G3) and butyl gallate (G4) inhibited NO production (IC50 = 7.9 μM e 2.0 μM, respectively). Butyl gallate and pentyl gallate (G5) inhibited CYP19 in approximately 60% at 90 μM, allowing a structure-activity... (Complete abstract click electronic access below)

Orientador: Christiane Pienna Soares / Banca: Dulce Helena Siqueira Silva / Banca: Denise Coutinho Endringer / Banca: Raquel Alves dos Santos / Banca: Massuo Jorge Kato / Resumo: A quimioprevenção do câncer é definida como o uso de produtos naturais ou sintéticos para atrasar, bloquear ou reverter o processo de carcinogênese. Produtos naturais apresentam uma diversidade de estruturas químicas que servem de modelo para o desenvolvimento de novos princípios ativos antitumorais e quimiopreventivos. Alcaloides guanidínicos presentes nas folhas de Pterogyne nitens apresentam atividade antitumoral e foram selecionados para os ensaios. O ácido gálico foi escolhido como modelo e seus derivados tiveram atividade quimiopreventiva descrita por ser produto natural antioxidante presente nas folhas de Alchornea glandulosa. Uma coleção de 70 substâncias foi classificada em 6 grupos de acordo com sua estrutura. Derivados de ácidos fenólicos, alcaloides guanidínicos, fenamatos, carvonas, xantonas, flavonas e chalconas preniladas foram avaliadas em ensaios de citotoxicidade por SRB em células MCF-7 e MDA-MB-231, e a atividade quimiopreventiva por meio de indução da enzima quinona-redutase (NQO1) em células Hepa 1c1c7, inibição in vitro de aromatase (CYP19), inibição de NF-κB ativado por TNFα e inibição da produção de NO em células RAW 264.7 estimuladas por LPS. Além disso, alcaloides guanidínicos nitensidina A (NTA), nitensidina B (NTB) e nitensidina T (NTT) foram avaliados pelo ensaio de MTT e a indução de apoptose por coloração com Hoechst 33342 e iodeto de propídio, ambos em células HepG2. A genotoxicidade do ácido gálico (GA) e galato de metila (G1) foi avaliada em células HepG2 pelo ensaio do cometa. GA e G1 apresentaram inibição de NF-κB (CI50 = 19,8 μM e 12,1 μM, respectivamente), sendo que GA provocou quebras de DNA significantes (P < 0,05) nas concentrações de 12 μM e 40 μM verificados pelo ensaio do cometa. Galato de propila (G3) e galato de butila... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Cancer chemoprevention is defined as the use of natural or synthetic products to delay, block or reverse the carcinogenesis process. Natural products presents a diversity of chemical structures that serve as template for the development of new active antitumor and chemopreventive agents. Guanidine alkaloids from the leaves of Pterogyne nitens have antitumor activity and were selected for the assays. Gallic acid, an antioxidant natural product present in the leaves of Alchornea glandulosa, was selected as template and its derivatives chemopreventive activity is reported. A collection of 70 compounds were classified into six groups according to their structure. Phenolic acid derivatives, guanidine alkaloids, fenamates, carvones, xanthones, prenylated flavones and chalcones were evaluated in cytotoxicity assays through SRB in MCF-7 and MDA-MB-231 cell lines, and chemopreventive activity by means of quinone-reductase (NQO1) induction in Hepa 1c1c7 cell line, in vitro aromatase (CYP19) inhibition, TNFα-activated NF-κB inhibition and NO production in LPS-stimulated RAW 264.7 cells. Guanidine alkaloids nitensidine A (NTA), nitensidine B (NTB) and nitensidine T (NTT) were evaluated through MTT assay and apoptosis induction with Hoechst 33342 and propidium iodide stain, both in HepG2 cell line. Genotoxicity of gallic acid (GA) and methyl gallate (G1) was evaluated in HepG2 cells by the comet assay. GA and G1 presented NF-κB inhibition (IC50 = 19.8 μM and 12.1 μM, respectively), and it resulted in significant (P < 0.05) DNA strand breaks at 12 μM and 40 μM as verified by the comet assay. Propyl gallate (G3) and butyl gallate (G4) inhibited NO production (IC50 = 7.9 μM e 2.0 μM, respectively). Butyl gallate and pentyl gallate (G5) inhibited CYP19 in approximately 60% at 90 μM, allowing a structure-activity... (Complete abstract click electronic access below) / Doutor

Magister Scientiae (Medical Bioscience) - MSc(MBS) / Laboratory studies, epidemiological investigations and human clinical trials indicate that flavonoids have important effects on cancer chemoprevention and therapy. Flavonoids may interfere in several steps that lead to cancer development but may also lead to toxicity as the inhibition of carcinogen-activating enzymes may also cause potential toxic flavonoid-drug interactions. However, the potential toxicity of these dietary components has not been well studied. The use of polyphenol enriched supplements prepared from South African herbal teas, rooibos(Aspalathus linearis)and honeybush (Cyclopia spp.) are being marketed to alleviate symptoms that are known to be “cured” by the herbal teas. However, there is a lack of information regarding the possible health promoting effects of these polyphenol-enriched extracts on xenobiotic metabolism. In the present study, the modulating effects of aspalathinenriched rooibos and mangiferin-enriched C. genistoides and C. subternata extracts on the gene expression of xenobiotic metabolising enzymes (XMEs) were investigated in vivo in the rat liver and kidneys. An in vitro study, utilising a primary rat hepatocyte cell model, was included to further evaluate changes in the expression of selected XMEs by the herbal tea extracts, including their major polyphenolic constituents, aspalathin and mangiferin. The use of the in vitro primary hepatocytes assay as a predictive cell model for the modulation of the expression of XMEs genes by the herbal tea extracts in vivo was critically evaluated.In the liver and kidneys, the C. subternata polyphenol-enriched herbal tea extract effected the majority of changes regarding the expression of XMEs genes when compared to the rooibos and C. genistoides. Variations in the modulation of gene expression of the XMEs by the herbal tea extracts were related to differences in their polyphenol constituents, although non-polyphenolic constituent could also be involved.Overall the herbal teas regulated alcohol,energy, drug and steroid metabolism in the liver, whereas in the kidneys the gene expression of phase I, phase II, steroid metabolising enzymes, as well as drug transporters were modulated. It would appear that the herbal teas are likely to exhibit both beneficial and adverse effects in vivo,depending on the specific organ, the xenobiotic and/or drug that are involved. The primary rat hepatocytes model display varying effects with respect to modulating gene expression of specific XMEs by the polyphenol-enriched herbal tea extracts. Apart from the reduction in 17 -hydroxysteroid dehydrogenase gene expression care should be taken to directly extrapolate the in vitro findings to changes that prevail in vivo.However, interesting results regarding the masking effect of complex mixture on the modulation of XME gene expression of individual polyphenols were encountered. In addition differences in the dose and duration of exposure between the in vitro and in vivo studies were not comparable and should be further explored to validate the in vitro primary hepatocytes model to predict changes in vivo. Future studies should investigate the effects of the herbal tea extracts, its polyphenols and metabolites on XME induction at a protein level as well as varying herb-drug-enzyme interactions.

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