Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Feb. 6, 2008). Includes bibliographical references (p. 142-161).

Wang Huan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 148-158). / Abstracts in English and Chinese. / TABLE OF CONTENTS --- p.I / LIST OF FIGURES AND TABLES --- p.VIII / ABSTRACT --- p.1 / 摘要 --- p.3 / Chapter CHAPTER 1 --- GENERAL INTRODUCTION / Chapter I. --- The essential factors related to cancer --- p.5 / Chapter a. --- Carcinogens --- p.5 / Chapter b. --- Carcinogenesis pathways --- p.7 / Chapter c. --- DNA adducts formation and breast cancer --- p.7 / Chapter II. --- Cytochrome P450 I enzyme family --- p.8 / Chapter a. --- CYP450 superfamily --- p.8 / Chapter b. --- CYP1A1 --- p.10 / Chapter c. --- CYP1B1 --- p.11 / Chapter III. --- Transactivation of CYP1 enzymes by aryl hydrocarbon receptor (AhR) --- p.12 / Chapter IV. --- Phase II enzyme UGT and cancer prevention --- p.13 / Chapter V. --- Estrogen metabolism and the hormone-dependent breast cancer --- p.15 / Chapter a. --- Estrogen and breast cancer initiation --- p.15 / Chapter b. --- Estrogen Receptor (ER) --- p.15 / Chapter c. --- Estradiol hydroxylation pathways --- p.15 / Chapter VI. --- Phytochemicals and cancer prevention --- p.18 / Chapter VII. --- Outline of this study --- p.20 / Chapter CHAPTER 2 --- MATERIALS AND METHODS / Chapter I. --- Chemicals --- p.21 / Chapter II. --- Cell culture and treatments --- p.21 / Chapter 1. --- Maintenance of cells --- p.21 / Chapter 2. --- Preparation of cell stock --- p.22 / Chapter 3. --- Cell recovery from liquid nitrogen stock --- p.22 / Chapter 4. --- Measurement of cell viability --- p.22 / Chapter 5. --- Preparation of cell lysates --- p.23 / Chapter 6. --- XRE-luciferase gene reporter assay --- p.23 / Chapter a. --- Transient transfection of cell using lipofectamine PLUS reagent --- p.23 / Chapter b. --- Dual Luciferase Assay --- p.24 / Chapter III. --- Enzyme Activities --- p.24 / Chapter 1. --- Isolation of microsomes --- p.24 / Chapter 2. --- EROD activities in intact cells --- p.24 / Chapter 3. --- EROD inhibition assay --- p.25 / Chapter IV. --- Manipulation of Nuclear Acid --- p.26 / Chapter 1. --- Preparation of transfected DNA --- p.26 / Chapter a. --- Separation and purification of DNA from agarose gel --- p.26 / Chapter b. --- Restriction digestion --- p.26 / Chapter c. --- Ligation of DNA fragments --- p.27 / Chapter d. --- Transformation of DH5a --- p.27 / Chapter e. --- Small scale plasmid purification from DH5a (mini prep) --- p.28 / Chapter f. --- Large scale plasmid isolation from DH5a (maxi-prep) --- p.28 / Chapter g. --- Construction of XRE activated luciferase reporter gene --- p.29 / Chapter 2. --- Measurement of DMBA-DNA adduct formation --- p.29 / Chapter 3. --- Semi-quantitative RT-PCR Assay --- p.30 / Chapter a. --- Isolation of RNA using TRIzol® Reagent --- p.30 / Chapter b. --- RT-PCR --- p.31 / Chapter V. --- Phase II enzyme-UGT activity assay --- p.32 / Chapter VI. --- HPLC for estradiol-hydroxylation analysis --- p.33 / Chapter 1. --- HPLC condition for hydroxyestradiol separation and measurement --- p.33 / Chapter 2. --- Determination of microsomal estradiol hydroxylase activity --- p.34 / Chapter 3. --- Assay of estradiol metabolism in MCF-7 cells --- p.34 / Chapter VII. --- Statistical Analysis --- p.35 / Chapter CHAPTER 3 --- CHALCONES ANTAGONIZE DMBA-INDUCED CARCINOGENESIS BY MODULATION OF CYP1A1/1B1 AND UGT ACTIVITIES / Chapter Part One --- Introduction --- p.36 / Chapter Part Two --- Results --- p.40 / Chapter Section One --- Chalcones antagonize DMBA carcinogenesis by inhibiting CYP1A1 and CYP1B1 activities --- p.40 / Chapter I. --- Chalcones inhibited DMBA-induced EROD activities in MCF-7 cells --- p.40 / Chapter II. --- Inhibition of chalcones on microsomal CYP1A1 & 1B1 enzyme activities --- p.43 / Chapter III. --- Reduction of DMBA-induced DNA adduct by chalcones --- p.52 / Chapter IV. --- Chalcones antagonized CYP1A1 XRE transactivation --- p.54 / Chapter V. --- Chalcones suppressed DMBA-induced CYP1 gene expression --- p.56 / Chapter Section Two --- Chalcones modulate DMBA carcinogenesis by regulating UGT activities --- p.63 / Chapter I . --- Chalcones regulated UGT1A1 gene expression in MCF-7 cells --- p.63 / Chapter II. --- Chalcones affected UGT enzyme activity in HepG2 cells --- p.70 / Chapter III. --- Chalcones regulated UGT1A1 gene expression in HepG2 cells --- p.73 / Chapter Part Three --- Discussion --- p.80 / Chapter I . --- Chalcones are potential chemopreventive agents --- p.80 / Chapter II. --- Chalcones modulated Phase I enzyme activities --- p.80 / Chapter III. --- Chalcones regulated Phase II enzyme activities --- p.82 / Chapter IV. --- Chalcones suppressed DMBA-induced DNA-adduct formation in MCF-7 cells --- p.82 / Chapter V. --- The anti-carcinogenic properties of chalcones and their structures --- p.83 / Chapter CHAPTER 4 --- EFFECTS OF PERILLYL ALCOHOL AND LIMONENE ON CYP1 AND UGT ENZYMES / Chapter Part One --- Introduction --- p.85 / Chapter Part Two --- Results --- p.87 / Chapter I. --- Perillyl alcohol and limonene modulated DMBA-induced CYP1A1/1B1 activities in MCF-7 cells --- p.87 / Chapter II. --- Perillyl alcohol and limonene regulated microsomal CYP1A1/1B1 activities --- p.89 / Chapter III. --- Perillyl alcohol and limonene regulated DMBA-induced DNA adduct formation in MCF-7 cells --- p.93 / Chapter IV. --- Perillyl alcohol and limonene regulated CYP1A1 & CYP1B1 gene expressions in MCF-7 cells --- p.95 / Chapter V. --- Effect of perillyl alcohol on CYP1A1 XRE transactivation --- p.97 / Chapter VI. --- Cytotoxic effect of perillyl alcohol and limonene on MCF-7 cells --- p.98 / Chapter VII. --- Perillyl alcohol and limonene modulated UGT1A1 gene expression in MCF-7 cells --- p.99 / Chapter VIII. --- Perillyl alcohol and limonene modulated UGT enzyme in HepG2 cells --- p.101 / Chapter Part Three --- Discussion --- p.106 / Chapter CHAPTER 5 --- LYCOPENE MEDIATED DMBA-INDUCED PHASE I & PHASE II ENZYME ACTIVITIES AND GENE EXPRESSIONS / Chapter Part Three --- Introduction --- p.109 / Chapter I. --- Biochemical properties of lycopene --- p.109 / Chapter II. --- Bioavailability of lycopene --- p.110 / Chapter III. --- Lycopene and cancers in hormonal sensitive tissues --- p.110 / Chapter Part Two --- Results --- p.111 / Chapter I . --- Lycopene modulated DMBA-induced CYP1A1/1B1 activities in MCF-7 cells --- p.111 / Chapter II. --- Lycopene competitively inhibited microsomal CYP1A1 & CYP1B1 activities --- p.113 / Chapter III. --- Lycopene suppressed DMBA-induced DNA adduct formation in MCF-7 cells --- p.115 / Chapter IV. --- Lycopene regulated CYP1A1 & CYP1B1 gene expression in MCF-7 cells --- p.116 / Chapter V. --- Effect of lycopene on CYP1A1 XRE trasactivation --- p.117 / Chapter VI. --- Cytotoxic effect of lycopene on MCF-7 cells --- p.118 / Chapter VII. --- Lycopene modulated UGT enzyme in MCF-7 cells --- p.119 / Chapter VIII. --- Lycopene modulated UGT enzyme in HepG2 cells --- p.121 / Chapter Part Three --- Discussion --- p.123 / Chapter CHAPTER 6 --- CHALCONES AND PERILLYL ALCOHOL REGULATEDCYP1A1 & CYP1B1 MEDIATED ESTRADIOL METABOLIZING PATHWAYS / Chapter Part One --- Introduction --- p.125 / Chapter I . --- Estrogen hydroxylation and human breast cancer risk --- p.125 / Chapter II. --- CYP1 enzymes catalyze estradiol-hydroxylation in human breast cancer cells --- p.126 / Chapter III. --- Phytochemicals mediate estrogen-hydroxylation pathways --- p.126 / Chapter Part Two --- Estrogen metabolite detection and separation by HPLC --- p.127 / Chapter Part Three --- Results --- p.129 / Chapter I . --- Perillyl alcohol modulated CYP1A1 & CYP1B1-mediated Estradiol hydroxylation --- p.129 / Chapter II. --- Kinetics assays of chalcones on CYP1A1 & CYP1B1 microsomes induced estradiol hydroxylation --- p.131 / Chapter III. --- Chalcones suppressed Estradiol-hydroxylase activities in MCF-7 cells --- p.137 / Chapter Part Four --- Discussion --- p.140 / Chapter CHAPTER 7 --- SUMMARY / Chapter I . --- Chalcones displayed inhibitory effects on DMBA-induced carcinogenesis --- p.142 / Chapter II. --- Perillyl alcohol and limonene modulated DMBA-induced carcinogenesis --- p.143 / Chapter III. --- Lycopene also possessed chemoproventive properties --- p.143 / APPENDIX 1 ABBREVIATIONS --- p.144 / APPENDIX 2 REAGENTS --- p.145 / APPENDIX 3 PRIMER LISTS --- p.147 / REFERENCE --- p.148

In order to gain insights into the underlying mechanisms, several methods including, flow cytometric, western blot and quantitative real-time PCR analyses were employed. AITC-induced cell growth inhibition in SW620 cells was mainly caused by G2/M arrest, which was accompanied by regulatory proteins modifications. Results of western blot and quantitative real-time PCR analysis showed clear downregulation of pivotal phosphatases Cdc25B and Cdc25C at both transcriptional and post-translational levels in AITC-treated cells. Subsequently, accumulation of inhibitory phosphorylation of Cdc2 on Thr14 and Tyr15 were resulted. Furthermore, an AITC induced apoptosis after prolonged exposure was observed. It was a caspase-mediated apoptosis as evidenced by the activation of initiator caspases (-8 and -9), effector caspases (-3 and -7) and cleavage of Poly (ADP-ribose) polymerase (PARP). Besides in vitro studies, the antitumor activity of AITC was further illustrated by a nude mice xenografts experiment. Treatment with 10 micromol AITC could effectively suppress the growth of SW620 xenografts in vivo. Taken together, our results suggest that AITC is an attractive candidate for future research in chemotherapy and chemoprevention. / Many epidemiological studies indicate that a high intake of cruciferous vegetables, such as cabbage, broccoli and Brussels sprouts, may reduce the risk of certain types of cancer. Glucosinolates in cruciferous vegetables and their digested products are suggested to play an important role in such chemoprevention. When plant tissue is physically damaged, glucosidic bonds are cleaved by endogenous myrosinase to produce various products. Among these products, isothiocyanates (ITCs) draw most of the attention because of their potent antitumor activities. But the molecular mechanism leading to such effects has not yet been defined. / The objective of this study was to investigate the chemotherapeutic potential of allyl isothiocyanate (AITC) towards human colorectal adenocarcinoma cells. Another commonly founded ITC, phenylethyl isothiocyanate (PEITC) was employed as a reference sample. The growth inhibitory effects of ITCs on different colorectal adenocarcinoma cells were investigated using in vitro cell models. Both AITC and PEITC were found to inhibit the growth and proliferation of Caco-2, COLO 201 and SW620 cells in a time- and dose-dependent manner. Based on sensitivity, the most vulnerable SW620 cells were chosen for further studies. In the following BrdU assay, IC50 values for 24-h AITC and PEITC treatments were determined to be 30.2 and 9.21 microM, respectively. At the same time, the effects of ITCs on human normal skin fibroblast Hs68 cells were also investigated. It was found that the survival of Hs68 cells was not affected by the treatments of AITC. However, the survival of Hs68 cells was greatly affected by PEITC-treatments in a dose- and time-dependent manner. / Lau, Wing Sze. / Adviser: Wong Yum Shing. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 115-128). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Absorption study showed that gossypetin was methoxylated and conjugated to form glucuronide during the first-pass metabolism after oral administration. Glucuronide conjugate was the major circulating form in the plasma. As determined by HPLC analysis, the total gossypetin concentration in the plasma was higher than the unchanged gossypetin indicating that most of gossypetin underwent first-pass metabolism. Moreover, urinary excretion was not a main elimination route. / Uses of foods and dietary supplements present a safe chemopreventive strategy. The application of phytochemicals for cancer prevention currently receives a great deal of attention. Flavonoids are known to be antiproliferative and may play an important role in the prevention of carcinogenesis. In addition to epidemiologic studies, basic science research to elucidate mechanisms and evaluate chemopreventive potential of phytochemicals is also necessary. In this study, gossypetin was found to have stronger antiproliferative activity when compared with quercetin, a well studied flavonoid, in human hepatocellular carcinoma (HepG2) cells and human breast carcinoma (MCF-7) cells. The results demonstrated that gossypetin induced growth inhibition in MCF-7 cell line by arresting cell cycle at G0/G1 phase. The inhibition of cell cycle progression was associated with the decrement of cyclin D1 expression, cdk6 kinase activity and phosphorylation of retinoblastoma protein (pRb). Although the cdk inhibitor p21 could not be detected, its upstream protein, p53 tumor suppressor protein, was activated by gossypetin in the MCF-7 cell line. Also, the proliferation of MCF-7 cells was suppressed through down-regulating the Erk1/2 pathway. / Ngai Lei-ka. / "August 2005." / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6156. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 222-250). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Chan Wai-Lung, William. / Thesis submitted in: December 2000. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 124-131). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (Chinese Version) --- p.iii / Acknowledgements --- p.v / Table of Contents --- p.vi / List of Tables --- p.ix / List of Figures --- p.xii / List of Abbreviations --- p.xvi / Chapter 1 --- Introduction --- p.1 / Literature Review --- p.4 / Chapter 1.1 --- A Brief Introduction of Cancer --- p.4 / Chapter 1.2 --- Natural Products as a Drug --- p.5 / Chapter 1.2.1 --- Development of terrestrial plants as a drug --- p.6 / Chapter 1.2.1.1 --- Anticancer drugs from terrestrial plants and Chinese medicinal herbs --- p.7 / Chapter 1.2.2 --- Development of marine organisms as a drug --- p.8 / Chapter 1.2.2.1 --- Anticancer drugs from marine organisms --- p.9 / Chapter 1.3 --- Anticlastogenic Study - an Anticancer Study --- p.10 / Chapter 1.3.1 --- Anticlastogenesis mechanisms study --- p.11 / Chapter 1.3.2 --- In vivo anticlastogenic study --- p.13 / Chapter 1.4 --- Anticlastogenic Study of Chinese Medicinal Herbs and Marine Algae --- p.17 / Chapter 1.4.1 --- Selection of nine Chinese medicinal herbs and three marine algae for anticlastogenic screening --- p.18 / Chapter 1.5 --- Methods of Investigation --- p.20 / Chapter 1.5.1 --- Extraction methods --- p.20 / Chapter 1.5.2 --- Single cell gel electrophoresis (Comet assay) --- p.21 / Chapter 2 --- Materials and Methods --- p.27 / Chapter 2.1 --- Materials --- p.27 / Chapter 2.1.1 --- Chinese medicinal herbs --- p.27 / Chapter 2.1.2 --- Marine algae --- p.27 / Chapter 2.1.3 --- Animals --- p.27 / Chapter 2.1.4 --- Chemicals and solutions --- p.28 / Chapter 2.2 --- Methods --- p.31 / Chapter 2.2.1 --- Crude extraction of natural products --- p.31 / Chapter 2.2.1.1 --- Water extraction of Chinese herbs --- p.31 / Chapter 2.2.1.2 --- Water extraction of marine algae --- p.31 / Chapter 2.2.2 --- Test for the effective dosage of clastogen ethyl methanesulfonate (EMS) to BALB/c mice --- p.31 / Chapter 2.2.2.1 --- In vitro test --- p.32 / Chapter 2.2.2.2 --- In vivo test --- p.32 / Chapter 2.2.3 --- Anticlastogenic bioassays --- p.33 / Chapter 2.2.3.1 --- In vitro anticlastogenic screening --- p.33 / Chapter 2.2.3.2 --- In vitro anticlastogenic mechanisms investigation --- p.33 / Chapter 2.2.3.3 --- In vivo anticlastogenic screening --- p.34 / Chapter 2.2.3.4 --- Different in vivo anticlastogenic treatment schedules --- p.35 / Chapter 2.2.4 --- Single cell gel electrophoresis assay (Comet assay) --- p.36 / Chapter 2.2.5 --- White blood cell viability determination --- p.37 / Chapter 2.2.6 --- Statistical analysis --- p.38 / Chapter 3 --- Results --- p.40 / Chapter 3.1 --- Extraction amount of different natural products and cell viability checking --- p.40 / Chapter 3.1.1 --- Chinese medicinal herbs --- p.40 / Chapter 3.1.2 --- Seaweeds --- p.40 / Chapter 3.1.3 --- Cell viability --- p.42 / Chapter 3.2 --- Effective dosage of clastogen EMS to BALB/c mice peripheral white blood cells --- p.42 / Chapter 3.2.1 --- In vitro --- p.42 / Chapter 3.2.2 --- In vivo --- p.42 / Chapter 3.3 --- In vitro anticlastogenic screen test and mechanisms investigation --- p.44 / Chapter 3.3.1 --- In vitro anticlastogenic screen test --- p.44 / Chapter 3.3.1.1 --- Chinese herbs --- p.44 / Chapter 3.3.1.2 --- Seaweeds --- p.53 / Chapter 3.3.2 --- In vitro anticlastogenic mechanisms investigation --- p.55 / Chapter 3.3.2.1 --- H. dilatata --- p.56 / Chapter 3.3.2.2 --- S. angustifolium --- p.56 / Chapter 3.3.2.3 --- S. siliquastrum --- p.63 / Chapter 3.4 --- In vivo anticlastogenic screen test and mechanisms investigation --- p.66 / Chapter 3.4.1 --- In vivo anticlastogenic screen test --- p.66 / Chapter 3.4.1.1 --- Chinese herbs --- p.66 / Chapter 3.4.1.2 --- Seaweeds --- p.73 / Chapter 3.4.2 --- Different treatment methods in in vivo anticlastogenic test --- p.86 / Chapter 3.4.2.1 --- Simultaneous application method --- p.86 / Chapter 3.4.2.2 --- Pre-drug treatment method --- p.91 / Chapter 3.4.2.3 --- Post drug treatment method --- p.91 / Chapter 4 --- Discussion --- p.94 / Chapter 4.1 --- Cell viability and water extracts in Chinese medicinal herbs and marine algae --- p.94 / Chapter 4.2 --- Clastogenic effect of EMS to pWBCs of BALB/c mice --- p.94 / Chapter 4.3 --- In vitro anticlastogenic screen test of nine water extracts of Chinese medicinal herbs and three water extracts of marine algae --- p.99 / Chapter 4.4 --- In vitro anticlastogenic mechanisms investigation of three \03 marine algae extracts --- p.103 / Chapter 4.5 --- In vivo anticlastogenic screen test of Chinese herbs extracts and seaweeds extracts --- p.108 / Chapter 4.6 --- Different administration methods in in vivo anticlastogenic test --- p.115 / Chapter 4.6.1 --- Intraperitoneal route of administration --- p.115 / Chapter 4.6.2 --- In vivo pre- and post-treatment methods --- p.116 / Chapter 5 --- Summary and Conclusion --- p.120 / References --- p.124

Submitted by CAMILA LEONEL DA SILVA null (camilaleonels_1@hotmail.com) on 2016-05-02T19:33:26Z No. of bitstreams: 1 TESE - Camila Leonel da Silva.pdf: 12839463 bytes, checksum: a432431aa8b8009a0183a4c0896c3e34 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-05-04T19:19:33Z (GMT) No. of bitstreams: 1 silva_cl_dr_sjrp.pdf: 12839463 bytes, checksum: a432431aa8b8009a0183a4c0896c3e34 (MD5) / Made available in DSpace on 2016-05-04T19:19:33Z (GMT). No. of bitstreams: 1 silva_cl_dr_sjrp.pdf: 12839463 bytes, checksum: a432431aa8b8009a0183a4c0896c3e34 (MD5) Previous issue date: 2016-04-23 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A transição epitélio-mesenquimal (EMT) é o processo pelo qual as células cancerosas a partir de tumores primários passam por uma conversão fenotípica para invadir e migrar, gerar metástases em tecidos ou órgãos distantes. Este processo pode ser induzido por fatores de crescimento, tais como Fator de Crescimento Transformante beta (TGF-β) e sua alta expressão tem sido implicada na angiogênese tumoral, na migração e invasão celular em muitos tipos de tumores. A expressão de ROCK-1 está associada com a malignidade dos tumores, enquanto a inibição desta molécula resulta em uma supressão significativa de metástases tumorais. A metformina, um fármaco utilizado no tratamento da diabetes, demonstrou inicialmente inibir a EMT e impedir o fenótipo mesenquimal pela repressão transcricional de pontos chave da regulação da EMT (ZEB1, TWIST1, SNAIL2, TGF-β) em células de câncer de mama. Os objetivos foram avaliar a expressão gênica e proteica de marcadores relacionados a metástase, em um estudo in vitro e in vivo, em linhagens de câncer de mama, após o tratamento com metformina, além do silenciamento gênico do TGF-β1 para inibição da transição epitélio-mesenquimal. Foi realizado a transfecção da linhagem celular metastática de tumor mamário canino CF41 de forma estável após a construção de um pequeno RNA de interferência para desenvolver derivados clonais que expressam níveis reduzidos de TGF-β1 (células TGF-β1sh). Este foi subsequentemente combinado com o tratamento com metformina, para analisar os efeitos sobre a migração de células, assim como a expressão dos marcadores de EMT E-caderina e N-caderina, quantificados através de imunofluorescência e do qRT-PCR. As linhagens mamárias humanas MCF-7 (não-metastática) e MDA-MB-231 (metastática) foram tratadas com metformina e inibidor Y27632, após a indução da EMT por TGF-β1 para examinar os efeitos sobre a migração destas células, bem como a expressão proteica dos marcadores ROCK-1, vimentina, E-caderina, CD44 e CD24 por imunocitoquímica. Em um estudo in vivo, as células não modificadas CF41 ou que expressam TGF-β1 shRNA foram injetadas na região inguinal de camundongos fêmea nude atímicos tratados com metformina. Os camundongos foram eutanasiados após o tratamento e os pulmões foram recolhidos para avaliação do número de metástases. As regiões metastáticas foram subsequentemente avaliadas pela expressão de N-caderina, E-caderina, vimentina e claudina-7 através da imuno-histoquímica. Foi possível avaliar que a taxa de migração e invasão foi menor em células TGF-β1sh, em comparação com as células parentais CF41 e esta inibição foi significativa quando combinado com o tratamento com metformina. As análises in vitro demonstraram que o tratamento com metformina reduziu a expressão de N-caderina e aumentou a expressão de E-caderina nas células CF41 e TGF-β1sh. Os resultados demonstram também que após a indução do TGF-β1 nas linhagens MCF-7 e MDA-MB-231 houve menor expressão das proteínas ROCK-1, vimentina, CD44 e CD24 em ambas as linhagens após tratamento com metformina e Y27632. Nas células MDA-MB-231 a expressão de E-caderina foi maior em todos os grupos de tratamento. O tratamento da linhagems MDA-MB-231 com metformina e Y27632 reduziu significativamente a invasão destas células. O estudo in vivo demonstrou que o tratamento com metformina reduziu o número de metástases pulmonares em animais portadores de tumores induzidos com as células TGF-β1sh. Houve diminuição da expressão de marcadores mesenquimais N-caderina e vimentina, e aumento da expressão de marcadores epiteliais E-caderina e claudina-7 nas metástases pulmonares. Assim, concluimos que este estudo confirma os benefícios do silenciamento do TGF-β1, além do tratamento com metformina e Y27632 como potenciais agentes terapêuticos em tumores de mama, bloqueando o processo de EMT e seu potencial metastático. / Epithelial mesenchymal transition (EMT) is the process by which cancer cells from primary tumors pass through a phenotypic conversion to invade and migrate, generating metastases in organs or tissues distant. This process can be induced by growth factors such as transforming growth factor beta (TGF-β) and its overexpression has been implicated in tumor angiogenesis, cell migration and invasion in many cancers. ROCK-1 expression is associated with the malignant character of tumors, while inhibiting this molecule results in a significant suppression of tumor metastasis. Metformin, a drug use for the treatment of diabetes, was previously shown to inhibit EMT by suppressing expression of key transcription factors in breast cancer cells. The aims were to evaluate the gene expression and protein expression of related markers metastasis, in a study in vitro and in vivo in breast cancer cell lines after treatment with metformin in addition to the gene silencing of TGF-β1 for inhibiting epithelial-mesenquimal transition. These aims were contemplated performing transfected of canine metastatic mammary tumor cell line CF41 with small interfering RNA constructs to develop clonal derivatives expressing reduced levels of TGF-β1 (TGF-β1sh cells). This was subsequently combined with metformin treatment, to look at effects on cell migration, as well as the expression of the EMT markers E-cadherin and N-cadherin, which were quantified by immunofluorescence and qRT-PCR. MCF-7 and MDA-MB-231 cell lines were treated with metformin and Y27632, after induction of EMT by TGF-β1, to examine the effects on cell migration as well as the protein expression of the ROCK-1 markers, vimentin, E-cadherin, CD44 and CD24 by immunocitochemistry. In an in vivo study, unmodified or TGF-β1 shRNA-expressing CF41 cells were injected in the inguinal region of nude athymic female mice that were treated with metformin. Mice were sacrificed after treatment and the lungs were collected to assess the number of metastases. Metastatic nodules were subsequently assessed for, N-cadherin, E-cadherin, vimentin and claudin-7 expression via immunohistochemistry. With the obtained results it was possible to assess the migration and invasion rate was lower in TGF-β1sh cells as compared to parental CF41 cells and this inhibition was significant when combined with metformin treatment. In vitro analyses demonstrated that metformin treatment reduced n-cadherin expression and increased E-cadherin expression in both CF41 and TGF-β1sh cells. After TGF-β1 induction in MDA-MB231 and MCF-7 cell lines, there was a lower protein expression of ROCK-1, vimentin, CD44 and CD24 in both cell lines after treatment with metformin and Y27632. In MDA-MB-231 cells, E-cadherin expression was increased in all treatment groups. Treatment of MDA-MB-231 cell line with metformin and Y27632 significantly reduced the invasion of these cells. In vivo studies demonstrated that metformin treatment reduced the number of lung metastases in animals bearing TGF-β1sh tumors. This paralleled a decreased expression of mesenchymal markers N-cadherin and vimentin, and increased expression of epithelial markers E-cadherin and claudin-7 in lung metastases.This study confirms the benefits of TGF-β1 silencing in addition to metformin and Y27632 as potential therapeutic agents in mammary tumors, by blocking EMT process and metastatic potential. / FAPESP: 2012/09778-1

Cancer chemoprevention uses noncytotoxic drugs or nutrients to prevent, retard, or delay carcinogenesis. The future of cancer chemoprevention depends on understanding key cellular growth and proliferation-controlling events, developing markers of molecular carcinogenesis, surrogate endpoint biomarkers, and targeted chemopreventive approaches.

This review summarizes the principles of cancer chemoprevention and discusses the evidence from epidemiologic and experimental studies and preclinical and clinical trials of potential colorectal chemopreventive agents. The putative mechanisms of action of the drugs in chemoprevention and their potential to reduce the incidence and mortality rate of colorectal neoplasms are discussed. The future of colorectal chemoprevention will depend on important new insights into molecular carcinogenesis of colorectal cancer, application of molecular markers as surrogate endpoints, and ultimately on therapeutic targets of prevention in clinical trials.

No description available.