by Leung Yuet Kin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 86-100). / Abstract also in Chinese. / List of Figures --- p.ix / List of Tables --- p.xii / List of Abbreviations --- p.xiii / Chapter Chapter One: --- Introduction / Chapter 1.1 --- Carcinogenicity of the tobacco products --- p.1 / Chapter 1.2 --- Biochemical Pathway involved in NNK metabolism --- p.5 / Chapter 1.2.1 --- Metabolic activation of NNK --- p.6 / Chapter 1.2.2 --- Detoxification of NNK --- p.8 / Chapter 1.3 --- Modulation of NNK carcinogenesis --- p.9 / Chapter 1.4 --- Mediation of NNK oxidation : chemoprevention by isothiocyanates --- p.11 / Chapter 1.5 --- Aim of study --- p.13 / Chapter 1.5.1 --- Experimental approaches --- p.15 / Chapter Chapter Two : --- Modulation of α-carbon hydroxylations in NNK metabolism / Chapter 2.1 --- Background --- p.17 / Chapter 2.2 --- Materials and Methods --- p.17 / Chapter 2.2.1 --- Chemicals --- p.17 / Chapter 2.2.2 --- Methods --- p.18 / Chapter 2.2.2.1 --- Preparation of rat microsomes --- p.18 / Chapter 2.2.2.2 --- Assay of NNK metabolism --- p.18 / Chapter 2.2.2.3 --- Determination of solvent extraction --- p.19 / Chapter 2.2.2.4 --- Determination of detergent effects --- p.19 / Chapter 2.2.2.5 --- HPLC analysis of NNK metabolites --- p.20 / Chapter 2.2.2.6 --- Study of strain differences between SD rats and F344 rats --- p.20 / Chapter 2.3 --- Results --- p.21 / Chapter 2.3.1 --- HPLC analysis of NNK metabolites --- p.21 / Chapter 2.3.2 --- Determination of solvent extraction --- p.22 / Chapter 2.3.3 --- Effects of detergents --- p.25 / Chapter 2.3.4 --- Study of strain differences using F344 rats and SD rats --- p.26 / Chapter 2.4 --- Discussion --- p.27 / Chapter Chapter Three : --- Modulation by potentiation of detoxification process in NNK metabolism / Chapter 3.1 --- Background --- p.30 / Chapter 3.2 --- Materials and Methods --- p.31 / Chapter 3.2.1 --- Chemicals --- p.31 / Chapter 3.2.2 --- Methods --- p.32 / Chapter 3.2.2.1 --- Preparation of rat microsomes --- p.32 / Chapter 3.2.2.2 --- Analysis of NNK metabolism --- p.32 / Chapter 3.2.2.3 --- UDP-glucuronosyltransferase Assay --- p.33 / Chapter 3.2.2.4 --- Cytochrome P450 2E1 Assay --- p.34 / Chapter 3.3 --- Results --- p.34 / Chapter 3.3.1 --- Screening tests of the effects of vitamins and drugs --- p.34 / Chapter 3.3.1.1 --- Male liver microsomes --- p.35 / Chapter 3.3.1.2 --- Female liver microsomes --- p.37 / Chapter 3.3.1.3 --- Male lung microsomes --- p.39 / Chapter 3.3.1.4 --- Female lung microsmes --- p.41 / Chapter 3.3.2 --- Kinetic analysis of vitamin C-palmitate on NNK reduction --- p.43 / Chapter 3.3.3 --- Effects of vitamin C-palmitate on UDP- glucuronosyltransferase --- p.47 / Chapter 3.3.4 --- Effects of vitamin C-palmitate on cytochrome P4502E1 (CYP2E1) --- p.48 / Chapter 3.4 --- Discussion --- p.50 / Chapter Chapter Four: --- Purification of carbonyl reductase from rat liver microsomes / Chapter 4.1 --- Background --- p.58 / Chapter 4.2 --- Materials and Methods --- p.58 / Chapter 4.2.1 --- Chemicals --- p.58 / Chapter 4.2.2 --- Methods --- p.59 / Chapter 4.2.2.1 --- Preparation of male rat liver microsomes --- p.59 / Chapter 4.2.2.2 --- Purification of carbonyl reductase from rat liver microsomes --- p.59 / Chapter A. --- Solubilization of microsomes --- p.59 / Chapter B. --- Chromatographic separation by octyl-Sepharose CL-4B --- p.60 / Chapter C. --- Chromatographic separation by DEAE-cellulose --- p.60 / Chapter 4.2.2.3 --- SDS polyacrylamide gel electrophoresis --- p.61 / Chapter 4.3 --- Results --- p.61 / Chapter 4.4 --- Discussion --- p.63 / Chapter Chapter Five : --- Summary and Discussion / Chapter 5.1 --- Summary --- p.66 / Chapter 5.2 --- Discussion --- p.67 / Chapter 5.2.1 --- Anticarcinogenesis of vitamin C in NNK-induced cancer through smoking --- p.67 / Chapter 5.2.2 --- Future studies on microsomal carbonyl reductase --- p.68 / Chapter 5.2.3 --- Future studies on UDP-glucuronidation of NNAL --- p.72 / Appendix A Effects of atropine on tolbutamide metabolism --- p.74 / Appendix B Recovery of keto acid and keto alcohol from the assay mixture ( without solvent extraction ) --- p.75 / Appendix C Calibration Curve of NNAL --- p.76 / Appendix D Effects of methanol on NNK carbonyl reduction --- p.77 / Appendix E Time course study of NNAL production at various concentrations of vitamin C-palmitate --- p.78 / Appendix F Time course assay of UDP-glucuronosyltransferase at various concentrations of vitamin C-palmitate --- p.80 / Appendix G Calculation of specific activity of UDP-Glucuronosyl transferase --- p.82 / Appendix H Calculation of specific activity of cytochrome P450 2E1 --- p.84 / References --- p.86

Hepatocellular carcinoma (HCC)is one of the commonly diagnosed cancers in the world. Most patients have poor prognosis due to late detection of disease. Ankyrin repeat and suppressor of cytokine signaling box protein 4(ASB4), as a member of the ASB family, possesses two domains, ankyrin repeat (AR) and suppressor of cytokine signaling (SOCS)box, which are responsible for recruiting the target proteins for proteasomal degradation. Previous study has demonstrated high expression level of ASB4 in metastatic HCC cells, implicating the properties of ASB4 in cancer invasiveness. With this hypothesis, various experiments were performed in this research project to elucidate the functional roles of ASB4 in HCC cells. The aim of this study is to characterize the roles of ASB4 in HCC by manipulating its expression level in HCC cell lines through gene knockdown and over-expression. Altering the level of ASB4 in HCC cells resulted in no significant effects on the cell proliferation rates. However, ASB4 was demonstrated to promote migration and invasion properties of HCC cells, as suppression of its level led to slower migration and made cells less invasive. Opposite effects on cell migration and invasion were observed when ASB4 was ectopically expressed. Regarding the regulatory mechanism of ASB4, miR-200a was demonstrated to be a negative regulator for ASB4. In summary, ASB4 is probably involved in the migration and invasion properties of HCC cells, and also, being regulated by miR-200a. / published_or_final_version / Surgery / Master / Master of Philosophy

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Graduation date: 1972

Thesis (Ph.D.)--Tufts University, 2005. / Adviser: Xiang-Dong Wang. Submitted to the School of Nutrition Science and Policy. Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Diss. (sammanfattning) Stockholm : Karol. inst., 2001. / Härtill 5 uppsatser.