Ong Chik Ying Rose. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 181-195). / Abstracts in English and Chinese. / Acknoledgements --- p.i / List of Abbreviations --- p.ii / Abstract --- p.iii / Abstract in Chinese --- p.v / List of Publications and Abstracts --- p.vii / List of Figures --- p.viii / List of Tables --- p.xi / Contents --- p.xii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Saponins --- p.3 / Chapter 1.1.1 --- Structure of saponins --- p.3 / Chapter 1.1.2 --- Occurrence of saponins --- p.7 / Chapter 1.1.3 --- Bioactivities of saponins --- p.8 / Chapter 1.2 --- Paris Polyphylla --- p.9 / Chapter 1.2.1 --- Chonglou --- p.11 / Chapter 1.3 --- Polyphyllin D --- p.12 / Chapter 1.4 --- Apoptosis --- p.15 / Chapter 1.4.1 --- Apoptosis and necrosis --- p.16 / Chapter 1.4.2 --- Initiation phase of apoptosis --- p.16 / Chapter 1.4.2.1 --- Extrinsic apoptotic pathway --- p.18 / Chapter 1.4.2.2 --- Intrinsic apoptotic pathway --- p.19 / Chapter 1.4.3 --- Execution phase of apoptosis --- p.19 / Chapter 1.4.4 --- Termination phase of apoptosis --- p.20 / Chapter 1.5 --- Multi-drug resistance (MDR) --- p.21 / Chapter 1.5.1 --- MDR mediated by decreased drug accumulation --- p.21 / Chapter 1.5.2 --- MDR mediated by enhanced anti-oxidant enzyme activities --- p.25 / Chapter 1.5.3 --- MDR mediated by enhanced detoxification of drugs --- p.25 / Chapter 1.5.4 --- MDR mediated by enhanced DNA repair system --- p.26 / Chapter 1.5.5 --- MDR mediated by altered apoptotic pathway --- p.26 / Chapter 1.5.6 --- Current strategies for overcoming multidrug resistance in cancer --- p.27 / Chapter 1.6 --- Hepatocellular carcinoma (HCC) --- p.30 / Chapter 1.7 --- Objectives of project --- p.32 / Chapter Chapter 2 --- Materials and Methods --- p.33 / Chapter 2.1 --- Materials --- p.34 / Chapter 2.1.1 --- Culture of Cells --- p.34 / Chapter 2.1.1.1 --- Cell lines --- p.34 / Chapter 2.1.1.2 --- Preservation of Cells --- p.35 / Chapter 2.1.2 --- Culture Media --- p.36 / Chapter 2.1.2.1 --- RPMI 1640 (Phenol Red Medium) --- p.36 / Chapter 2.1.2.2 --- RPMI 1640 (Phenol Red-free Medium) --- p.36 / Chapter 2.1.3 --- Buffers and Reagents --- p.37 / Chapter 2.1.3.1 --- Buffer for Common Use --- p.37 / Chapter 2.1.3.2 --- Reagents for Annexin-V-FITC/PI Assay --- p.37 / Chapter 2.1.3.3 --- Reagents for Western Blotting Analysis --- p.37 / Chapter 2.1.4 --- Chemicals --- p.40 / Chapter 2.1.4.1 --- Fluorescence Dyes --- p.40 / Chapter 2.1.4.2 --- Antibodies --- p.41 / Chapter 2.1.4.3 --- Other Chemicals --- p.42 / Chapter 2.1.5 --- Summary of chemicals used in this study --- p.43 / Chapter 2.2 --- Methods --- p.48 / Chapter 2.2.1 --- In vitro Cell Cytotoxicity Assay --- p.48 / Chapter 2.2.1.1 --- AlamarBlue Assay --- p.48 / Chapter 2.2.2 --- Flow Cytometry --- p.50 / Chapter 2.2.2.1 --- Analysis by Flow Cytometry --- p.50 / Chapter 2.2.2.2 --- Determination of Apoptotic and Late Apoptotic/Necrotic Cells with Annexin-V-FITC/PI Cytometric Analysis --- p.50 / Chapter 2.2.2.3 --- Determination of Mitochondrial Membrane Potential in cells --- p.51 / Chapter 2.2.2.4 --- Determination of Hydrogen Peroxide (H2O2) Release in cells --- p.52 / Chapter 2.2.2.5 --- Measurement of doxorubicin accumulation in cells --- p.53 / Chapter 2.2.2.6 --- Determination of P-glycoprotein expression level in cells --- p.54 / Chapter 2.2.2.7 --- Determination of mitochondrial depolarization and swellingin isolated mitochondria --- p.54 / Chapter 2.2.3 --- Methods involved in DNA sequencing of MDRl promoter --- p.56 / Chapter 2.2.3.1 --- DNA extraction --- p.56 / Chapter 2.2.3.2 --- DNA and Gel Band Purification --- p.56 / Chapter 2.2.3.3 --- Assessment of DNA amount --- p.57 / Chapter 2.2.3.4 --- Polymerase Chain Reaction --- p.57 / Chapter 2.2.3.5 --- Agarose Gel Electrophoresis --- p.59 / Chapter 2.2.3.6 --- Preparation for DNA sequencing --- p.59 / Chapter 2.2.4 --- Western Blotting Analysis --- p.61 / Chapter 2.2.4.1 --- Preparation of Proteins from Cells --- p.61 / Chapter 2.2.4.2 --- Preparation of proteins from isolated mitochondria --- p.63 / Chapter 2.2.4.3 --- Protein analysis with Western analysis --- p.63 / Chapter 2.2.5 --- Confocal laser scanning microscopy (Confocal microscopy) --- p.66 / Chapter 2.2.5.1 --- Analysis with confocal microscopy --- p.66 / Chapter 2.2.5.2 --- Determination of mitochondrial changes in cells by confocal microscopy --- p.66 / Chapter 2.2.5.3 --- Determination of lysosomal rupture in cells by confocal microscopy --- p.67 / Chapter 2.2.6 --- Mitochondrial isolation --- p.68 / Chapter Chapter 3 --- Results 一 Resistance Mechanisms in RHepG2 cells --- p.69 / Chapter 3.1 --- Resistance of RHepG2 cells towards various chemical agents --- p.70 / Chapter 3.1.1 --- RHepG2 cells are resistant to doxorubicin --- p.70 / Chapter 3.1.2 --- RHepG2 cells are resistant to taxol --- p.72 / Chapter 3.1.3 --- RHepG2 cells are resistant to valinomycin --- p.74 / Chapter 3.2 --- Resistance mechanism in RHepG2 cells --- p.76 / Chapter 3.2.1 --- Reduced doxorubicin accumulation is observed in RHepG2 cells --- p.76 / Chapter 3.2.2 --- More P-glycoproteins on the cell surface was observed in RHepG2 cells --- p.80 / Chapter 3.2.3 --- Inhibition of P-glycoprotein activity increased doxorubicin accumulation in RHepG2 cells --- p.82 / Chapter 3.2.4 --- HepG2 and RHepG2 cells contain the same P-glycoprotein promoter region --- p.86 / Chapter 3.2.5 --- RHepG2 over-expressed Bcl-2 --- p.91 / Chapter 3.2.6 --- HepG2 and RHepG2 cells had the same level of Bax protein --- p.93 / Chapter Chapter 4 --- Results - Effects of Polyphyllin D in HepG2 and RHepG2 cells --- p.95 / Chapter 4.1 --- Cytotoxicity of Polyphyllin D in HepG2 and RHepG2 cells --- p.96 / Chapter 4.1.1 --- Polyphyllin D exhibited cytotoxic effect in both HepG2 and RHepG2 cells --- p.96 / Chapter 4.2 --- Apoptotic mechanism caused by Polyphyllin D in HepG2 and RHepG2 cells --- p.93 / Chapter 4.2.1 --- Polyphyllin D caused apoptosis in HepG2 and RHepG2 cells --- p.98 / Chapter 4.2.2 --- Polyphyllin D did not activate caspase8 --- p.103 / Chapter 4.2.3 --- Polyphyllin D did not concentrate on the plasma membrane of cells --- p.106 / Chapter 4.2.4 --- Polyphyllin D did not change Bcl-2 level in HepG2 and RHepG2 cells --- p.109 / Chapter 4.2.5 --- Polyphyllin D treatment enhanced Bax protein expression in both HepG2 and RHepG2 cells --- p.111 / Chapter 4.2.6 --- Polyphyllin D caused cytochrome c and AIF release in HepG2 and RHepG2 cells --- p.113 / Chapter 4.2.7 --- Polyphyllin D induced mitochondrial membrane depolarization in HepG2 and RHepG2 cells --- p.118 / Chapter 4.2.8 --- Polyphyllin D caused mitochondrial swelling in HepG2 and clustering of mitochondriain RHepG2 cells --- p.122 / Chapter 4.2.9 --- "Polyphyllin D caused H202 release in HepG2 and RHepG2 cells, and the cytotoxic effects of Polyphyllin D could be reduced by NAC" --- p.127 / Chapter 4.2.10 --- Polyphyllin D caused permeabilization of lysosomes --- p.132 / Chapter 4.3 --- Site of action of Polyphyllin D in cells --- p.135 / Chapter 4.3.1 --- Purity of isolated mitochondria --- p.135 / Chapter 4.3.2 --- Polyphyllin D caused cytochrome c release from the HepG2 and RHepG2 isolated mitochondria --- p.137 / Chapter 4.3.3 --- Polyphyllin D induced mitochondrial depolarization in HepG2 and RHepG2 isolated mitochondria --- p.139 / Chapter 4.3.4 --- Polyphyllin D caused mitochondrial swelling in HepG2 and RHepG2 isolated mitochondria --- p.142 / Chapter 4.4 --- Resistance reversal effects of Polyphyllin D in RHepG2 cells --- p.144 / Chapter 4.4.1 --- Polyphyllin D increased doxorubicin accumulation in RHepG2 cells --- p.144 / Chapter 4.4.2 --- P-glycoprotein expression was not down-regulated after Polyphyllin D treatment --- p.146 / Chapter 4.4.3 --- Co-treatment of doxorubicin with Polyphyllin D had enhanced cytotoxic effect --- p.148 / Chapter Chapter 5 --- Discussion - Resistance mechanisms in RHepG2 cells --- p.150 / Chapter 5.1 --- Resistance of RHepG2 cells towards various chemical reagents --- p.151 / Chapter 5.2 --- Resistance mechanisms in RHepG2 cells --- p.154 / Chapter Chapter 6 --- Discussion - Effects of Polyphyllin D in HepG2and RHepG2 cells --- p.159 / Chapter 6.1 --- Cytotoxicity of Polyphyllin D in HepG2 and RHepG2 cells --- p.160 / Chapter 6.2 --- Apoptotic mechanisms caused by Polyphyllin D in HepG2 and RHepG2 cells --- p.162 / Chapter 6.3 --- Site of action of Polyphyllin D in HepG2 andRHepG2 cells --- p.172 / Chapter 6.4 --- Resistance reversal effects of Polyphyllin D in RHepG2 cells --- p.175 / Chapter Chapter 7 --- Future Perspectives --- p.177 / Chapter Chapter 8 --- Conclusion --- p.179 / References

by Fok Ho Yin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 114-120). / Abstracts in English and Chinese. / Acknowledgements --- p.ii / Abstract --- p.iii / 槪論 --- p.v / List of Abbreviations --- p.vi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Toxicological studies on the effect of Ilex latifolia extract and its saponin-enriched Fraction --- p.19 / Chapter Chapter 3 --- Hypoglycemic effect of Ilex latifolia extract and its saponin-enriched fraction --- p.51 / Chapter Chapter 4 --- Hypolipidemic effect of Ilex latifolia extract and its saponin-enriched fraction --- p.78 / Chapter Chapter 5 --- Conclusion --- p.109 / References --- p.114

by Cheung Yuen-Nei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 194-208). / Abstracts in English and Chinese. / Acknowledgement --- p.i / Abstract --- p.ii / 摘要 --- p.iv / Contents --- p.vi / List of Figures --- p.xii / List of Tables --- p.xv / Abbreviations --- p.xvi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1 --- Introduction --- p.2 / Chapter 1.1 --- Characteristic of Saponins --- p.3 / Chapter 1.1.1 --- Occurrence of Saponins --- p.3 / Chapter 1.1.2 --- General Properties of Saponins --- p.3 / Chapter 1.1.2.1 --- Emulsifying Agents --- p.3 / Chapter 1.2.2.2 --- Forming Complex with Cholesterol --- p.4 / Chapter 1.1.2.3 --- Hemolytic Property --- p.4 / Chapter 1.1.3 --- Structure of Saponins --- p.5 / Chapter 1.1.3.1 --- Categories of Saponins --- p.5 / Chapter 1.1.3.1.1 --- Triterpene Saponins --- p.5 / Chapter 1.1.3.1.2 --- Steroid Saponins --- p.5 / Chapter 1.1.3.2 --- Monodesmosidic and Bidesmosidic Saponins --- p.7 / Chapter 1.1.4 --- Biological and Pharmacological Properties of Saponins --- p.9 / Chapter 1.1.4.1 --- Anti-microbial Activity --- p.9 / Chapter 1.1.4.1.1 --- Anti-fungal Activities --- p.9 / Chapter 1.1.4.1.2 --- Anti-bacterial Activities --- p.10 / Chapter 1.1.4.1.3 --- Anti-viral Activities --- p.10 / Chapter 1.1.4.2 --- Insecticidal Activity --- p.10 / Chapter 1.1.4.3 --- Molluscicidal Activity --- p.10 / Chapter 1.1.4.4 --- Hypocholesterolemic Activity --- p.11 / Chapter 1.1.4.5 --- Anti-ulcer Activity --- p.11 / Chapter 1.1.4.6 --- Contraceptive Activity --- p.12 / Chapter 1.1.4.7 --- Immunomodulatory Activities --- p.12 / Chapter 1.1.4.7.1 --- Direct Immunostimulation --- p.12 / Chapter 1.1.4.7.2 --- Acting as Immuno-adjuvants --- p.13 / Chapter 1.1.4.8 --- Anti-tumor Activity --- p.14 / Chapter 1.1.4.8.1 --- Anti-carcinogenesis --- p.15 / Chapter 1.1.4.8.2 --- Suppression of Tumor Growth --- p.16 / Chapter 1.1.5 --- Anti-tumor Activity of Steroid Saponins --- p.18 / Chapter 1.1.5.1 --- Diosgenin Steroid Saponin --- p.18 / Chapter 1.1.5.2 --- Hong Kong Compounds --- p.18 / Chapter 1.1.5.3 --- Hong Kong18 --- p.21 / Chapter 1.2 --- Human Hepatocellular Carcinoma (HCC) --- p.24 / Chapter 1.2.1 --- The Incidence of Liver Cancer --- p.24 / Chapter 1.2.2 --- Classification of Liver Cancer --- p.24 / Chapter 1.2.3 --- Human Hepatocellular Carcinoma Cell Lines --- p.25 / Chapter 1.2.3.1 --- Human Hepatocellular Carcinoma Cell Line HepG2 --- p.25 / Chapter 1.2.3.2 --- Multidrug Resistant Human Hepatocellular Carcinoma Cell Line R-HepG2 --- p.27 / Chapter 1.2.3.2.1 --- Mechanisms of Multidrug Resistance --- p.28 / Chapter 1.2.3.2.2 --- Structure and Characteristics of P-glycoprotein --- p.29 / Chapter 1.2.3.2.3 --- Methods in Dealing with P-glycoprotein Over-expressed MDR Cells --- p.31 / Chapter 1.3 --- Objectives of the Project --- p.32 / Chapter 1.3.1 --- Study of the Anti-tumor Activities of Hong Kong 18 on Human Hepatocellular Carcinoma Cell Line HepG2 and Unravel the Underlying Mechanisms --- p.32 / Chapter 1.3.2 --- Study of the Anti-tumor Activities of Hong Kong 18on Multidrug Resistant Human Hepatocellular Carcinoma Cell Line R-HepG2 and Unravel the Underlying Mechanisms --- p.32 / Chapter Chapter 2 --- Materials and Methods --- p.33 / Chapter 2.1 --- Materials --- p.34 / Chapter 2.1.1 --- Cell Culture --- p.34 / Chapter 2.1.1.1 --- Cell Lines --- p.34 / Chapter 2.1.1.2 --- Culture Media --- p.35 / Chapter 2.1.2 --- Reagents and Buffers --- p.36 / Chapter 2.1.2.1 --- Phosphate Buffered Saline (PBS) --- p.36 / Chapter 2.1.2.2 --- Reagents and Buffers for DNA Fragmentation --- p.36 / Chapter 2.1.2.3 --- Reagents and Buffers for Western Analysis --- p.37 / Chapter 2.1.2.4 --- Reagents and Buffer for Caspases Activities --- p.39 / Chapter 2.1.2.5 --- Fluorescent Dyes used for Flow Cytometry --- p.39 / Chapter 2.1.3 --- Chemicals --- p.39 / Chapter 2.2 --- Methods --- p.46 / Chapter 2.2.1 --- MTT Assay --- p.46 / Chapter 2.2.2 --- Determination of Cell Viability --- p.46 / Chapter 2.2.3 --- Purification of Macrophages from balb/c Mice --- p.47 / Chapter 2.2.4 --- Hemolysis Assay --- p.47 / Chapter 2.2.5 --- In vivo Studies of the Toxicity of HK18 --- p.48 / Chapter 2.2.6 --- DNA Fragmentation Assay --- p.50 / Chapter 2.2.7 --- Detection of Apoptotic and Necrotic / Late Apoptotic Cells Death by Flow Cytometry with Annexin V-FITC / PI --- p.51 / Chapter 2.2.8 --- Detection of Mitochondrial Membrane Potential by JC-1 Fluorescent Dye --- p.52 / Chapter 2.2.9 --- Detection of Intracellular Ca Level by Flow Cytometry with Fluo-3 Fluorescent Dye --- p.52 / Chapter 2.2.10 --- Detection of Intracellular Hydrogen Peroxide Level by Flow Cytometry with DCF Fluorescence Dye --- p.53 / Chapter 2.2.11 --- Simultaneous Detection of Mitochondrial Membrane Potential and Intracellular Ca2+ or Mitochondrial Membrane Potential and Intracellular Hydrogen Peroxide --- p.54 / Chapter 2.2.12 --- Western Analysis --- p.55 / Chapter 2.2.12.1 --- Total Protein Extraction --- p.55 / Chapter 2.2.12.2 --- Extraction of Cytosolic Proteins --- p.59 / Chapter 2.2.13 --- Determination of Caspases Enzymatic Activity --- p.63 / Chapter 2.2.14 --- Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) --- p.67 / Chapter 2.2.14.1 --- RNA Extraction by TRIzol Reagent --- p.67 / Chapter 2.2.14.2 --- Reverse Transcription --- p.68 / Chapter 2.2.14.3 --- Polymerase Chain Reaction --- p.68 / Chapter 2.3 --- Statistic Analysis --- p.71 / Chapter Chapter 3 --- Cytotoxicity of HK18 --- p.72 / Chapter 3.1 --- Cytotoxicity of HK18 on HepG2 Cells --- p.73 / Chapter 3.1.1 --- Study of the Cytotoxic Activity of HK18 on HepG2 Cells by MTT Assay --- p.73 / Chapter 3.1.2 --- Study of the Cytotoxic Activity of HK18 on HepG2 Cells by Tryphan Blue Exclusion Assay --- p.76 / Chapter 3.2 --- Cytotoxicity of HK18 on R-HepG2 Cells --- p.78 / Chapter 3.2.1 --- Study of the Cytotoxic Activity of HK18 on R-HepG2 Cells by MTT Assay --- p.78 / Chapter 3.2.2 --- Study of the Cytotoxic Activity of HK18 on R-HepG2 Cells by Tryphan Blue Exclusion Assay --- p.81 / Chapter 3.3 --- Cytotoxicity of HK18 on Macrophages --- p.83 / Chapter 3.4 --- Hemolytic Activity of HK18 --- p.85 / Chapter 3.5 --- In vivo Study of the Toxicity of HK18 --- p.87 / Chapter Chapter 4 --- Mechanistic Study of HK18 on HepG2 Cells --- p.90 / Chapter 4.1 --- Hallmarks of Apoptosis Induced by HK18 on HepG2 Cells --- p.91 / Chapter 4.1.1 --- Induction of Phosphatidylserine Externalization by HK18 on HepG2 Cells --- p.91 / Chapter 4.1.2 --- Induction of DNA Fragmentation by HK18 of HepG2 Cells --- p.97 / Chapter 4.2 --- Study of the Underlying Mechanisms of HK18 Induced Apoptosis in HepG2 Cells --- p.99 / Chapter 4.2.1 --- The Role of Mitochondria in HK18 Induced Apoptosis of HepG2 Cells --- p.99 / Chapter 4.2.1.1 --- HK18 Induced Mitochondrial Membrane Depolarization in HepG2 Cells --- p.101 / Chapter 4.2.1.2 --- Addition of Bongkrekic Acid Reduced HK18 Cytotoxicity on HepG2 Cells --- p.105 / Chapter 4.2.1.3 --- Elevation of Intracellular Hydrogen Peroxide Level in HK18 Treated HepG2 Cells --- p.108 / Chapter 4.2.1.4 --- Elevation of Intracellular Ca2+ Level in HK18 Treated HepG2 Cells --- p.114 / Chapter 4.2.1.5 --- HK18 Induced Cytochrome c and AIF Released from Mitochondria of HepG2 Cells --- p.120 / Chapter 4.3 --- Downstream Biochemical Changes Induced by HK18 on HepG2 Cells --- p.123 / Chapter 4.3.1 --- Activation of Caspase 3 of HepG2 Cells by HK18 as Demonstrated by Western Blot --- p.123 / Chapter 4.3.2 --- Induction of Caspases Activities of HepG2 Cells by HK18 as Demonstrated by Enzymatic Activity Assays --- p.125 / Chapter 4.4 --- Down-regulation of Anti-apoptotic Bcl-2 Family Members of HepG2 Cells by HK18 --- p.129 / Chapter Chapter 5 --- Mechanistic Study of HK18 on R-HepG2 Cells --- p.133 / Chapter 5.1 --- Hallmarks of Apoptosis Induced by HK18 on R-HepG2 Cells --- p.134 / Chapter 5.1.1 --- Induction of Phosphatidylserine Externalization by HK18 on R-HepG2 Cells --- p.134 / Chapter 5.1.2 --- Induction of DNA Fragmentation by HK18 of R-HepG2 Cells --- p.137 / Chapter 5.2 --- Study of the Underlying Mechanisms of HK18 Induced Apoptosis in R-HepG2 Cells --- p.139 / Chapter 5.2.1 --- The Role of Mitochondria in HK18 Induced Apoptosis of R-HepG2 Cells --- p.139 / Chapter 5.2.1.1 --- HK18 Induced Mitochondrial Membrane Depolarization in R-HepG2 Cells --- p.139 / Chapter 5.2.1.2 --- Addition of Bongkrekic Acid Reduced HK18 Cytotoxicity on R-HepG2 Cells --- p.142 / Chapter 5.2.1.3 --- Elevation of Intracellular Hydrogen Peroxide Level in HK18 Treated R-HepG2 Cells --- p.144 / Chapter 5.2.1.4 --- Elevation of Intracellular Ca2+ Level in HK18 Treated R-HepG2 Cells --- p.146 / Chapter 5.3 --- Downstream Biochemical Changes Induced by HK18 on R-HepG2 Cells --- p.148 / Chapter 5.3.1 --- Activation of Caspase 3 of R-HepG2 Cells by HK18 as Demonstrated by Western Blot --- p.148 / Chapter 5.3.2 --- Induction of Caspases Activation of R-HepG2 Cells by HK18 as Demonstrated by Enzymatic Activity Assays --- p.150 / Chapter 5.4 --- Down-regulation of the Anti-apoptotic Bcl-2 Protein of R-HepG2 Cells by HK18 --- p.154 / Chapter 5.5 --- HK18 was Not a Substrate of P-glycoprotein Contents --- p.156 / Chapter Chapter 6 --- Discussion --- p.158 / Chapter 6.1 --- Cytotoxicity of HK18 --- p.159 / Chapter 6.1.1 --- HK18 was Cytotoxic to the Human Hepatocellular Carcinoma Cell Line HepG2 and Multidrug Resistant Human Hepatocellular Carcinoma Cell Line R-HepG2 --- p.159 / Chapter 6.1.2 --- Study of the Toxicity of HK18 --- p.160 / Chapter 6.2 --- Mechanistic Studies of the Cytotoxic Effects of HK18 on HepG2 Cells --- p.161 / Chapter 6.2.1 --- Apoptotic Cell Death Induction of HK18 on HepG2 Cells --- p.161 / Chapter 6.2.2 --- Studies of the Underlying Mechanisms of HK18 Induced Apoptosis of HepG2 Cells --- p.162 / Chapter 6.3 --- Mechanistic Studies of the Cytotoxic Effects of HK18 on R-HepG2 Cells --- p.181 / Chapter 6.3.1 --- Apoptotic Cell Death Induction of HK18 on R-HepG2 Cells --- p.181 / Chapter 6.3.2 --- Studies of the Underlying Mechanisms of HK18 Induced Apoptosis of HepG2 Cells --- p.181 / Chapter Chapter 7 --- Future Perspectives --- p.190 / Chapter Chapter 8 --- References --- p.193

By using the acridine orange (AO) staining method to examine the release of contents from lysosomes, it was found that PD released AO into the cytosol in both cell lines. However, the releasing pattern of HepG2 and RHepG2 was quite different. Upon PD treatment, the release of AO in HepG2 cells was graduate and slow while that in RHepG2 was sudden and sharp. / Cancer is one of the leading causes of death in the world. During cancer treatment, development of multidrug resistance (MDR) is always the major cause of failures of chemotherapy in human cancers. In our project, hepatocarcinoma HepG2 and its drug-resistant derivatives RHepG2 with MDR towards doxorubicin (Dox), fenretinide and Taxol were used to examine the differences in their response towards various anti-cancer agents. / From the AO staining, most of the lysosomes were found in the cytosol near the nucleus. However, some lysosomes were found inside the nucleus occasionally. When we double stained the HepG2 cells with DiOC6(3), it was found that the lysosomes were actually located inside the nuclear tubules. However, no such lysosome migration was observed after treating the HepG2 cells with PD. Thus, lysosomes inside the nuclear tubules might not be involved in the PD-induced lysosomal pathway. The mechanism that leads to the migration of lysosomes into the nuclear tubules is still unclear. / From the Western blot analysis, cathepsin D (Cat D) and cathepsin L (Cat L) were both released from the lysosomes after treating the two cell lines with PD. Also, it seemed likely that Cat L was released earlier than that of cyt c. This implies that lysosomal permeabilization is an early event in apoptosis. With the use of siRNA technology, it was found that RHepG2 with the knockdown of Cat D and Cat L were more tolerant and vulnerable towards PD, respectively. These suggest that Cat D and Cat L might act oppositely in the apoptotic pathway. Furthermore, the addition of Cat D inhibitor, pepstatin A, blocked the PD-mediated cell death in RHepG2 cells further confirms that Cat D is a pro-apoptotic protein that is involved in the apoptotic pathway. / In conclusion, PD was a potent anti-cancer agent that could reverse the MDR properties of RHepG2 and kill more RHepG2 cells through lysosomal and mitochondrial apoptotic pathway. / Next, we investigated the underlying killing mechanism and found out that PD switched on both the mitochondrial and lysosomal apoptotic pathway in both cell lines. Our results indicate that PD was able to depolarize mitochondrial membrane potential and release apoptosis inducing factor (AIF) and cytochrome c (cyt c) from the mitochondria to cytosol. Also, PD was able to act on isolated mitochondria directly, causing a stronger mitochondrial membrane permeabilization and more AIF release from the RHepG2 than that of the parental cells. / Polyphyllin D (PD) is a saponin found in a tradition Chinese herb, Paris polyphylla, which has been used to treat liver cancers in China for many years. Interestingly, from the MTT assays, we found out that RHepG2 (IC50: 2.0 muM) was more sensitive towards PD when compared to that of its parental cells (IC50: 3.9 muM). To keep the MDR properties, RHepG2 cells were routinely cultured with 1.2 muM of Dox. When we cultured RHepG2 in the absence of Dox but with 1.2 muM of PD for 28 days, the Pgp expression could not be maintained. However, such high expression level of Pgp was maintained when RHepG2 cells were treated with vincristine (1.2 muM) in the absence of Dox. This indicates that vincristine was a substrate of Pgp to keep the Pgp expression in RHepG2 cells while PD was not. / When incubated with different concentrations of Dox, RHepG2 accumulated less Dox than that of its parental HepG2 cells. When probed by the antibody against P-glycoprotein (Pgp), RHepG2 showed a strong Pgp expression. With the addition of Pgp modulator, verapamil, RHepG2 accumulated more Dox. All these findings indicate that Pgp is a mediator giving rise the MDR in RHepG2 cells. However, RHepG2 had a higher resistance to Dox than its parental line even co-cultured with verapamil. RHepG2 remained viable at the intracellular Dox concentration that was toxic to HepG2 cells. These observations suggest that the MDR properties of RHepG2 involved multiple mechanisms in addition to the effect of Pgp. / Lee, Kit Ying Rebecca. / "August 2007." / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4735. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 241-253). / 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.