神經母細胞瘤是一種交感神經系統的腫瘤。它是最常見的兒童顱外實體瘤。神經母細胞瘤約佔兒童腫瘤的8-10%，佔15%的兒童腫瘤死亡率。目前神經母細胞瘤的治療方法包括外科手術， 化學藥物治療， 放射治療， 幹細胞移植， 誘導分化治療和免疫治療。 然而，這些治療方法通常會導致許多無法避免的嚴重的副作用。因此，開發能高效抑制神經母細胞瘤但對正常細胞無明顯副作用的新型藥物顯得至關重要。最近，用來源於天然產物或中藥的化合物治療癌症引起了科學家的廣泛關注。靛玉紅-3’-肟（Indirubin-3’-oxime, I3M）和色胺酮（tryptanthrin）分別是從板藍根中分離得到的靛藍生物鹼和吲哚喹唑啉類生物鹼。據研究報導，這兩種生物鹼具有多種生物學和藥理學作用，包括抗菌，抗炎症和抗腫瘤作用。它們對體外的多種人腫瘤細胞具有抗腫瘤作用。然而，它們對人神經母細胞瘤的調節作用和作用機理仍不太清楚。在我的博士研究課題中，我們對板藍根生物鹼包括靛玉紅-3’-肟和色胺酮對人神經母細胞瘤的抗腫瘤活性和作用機制進行了研究和探討。 / 首先，我們研究了靛玉紅-3’-肟對人神經母細胞瘤的抗腫瘤活性和作用機制。實驗結果表明，靛玉紅-3’-肟能夠抑制人神經母細胞瘤LA-N-1, SH-SY5Y 和 SK-N-DZ細胞系的生長，並且其抑制效果呈時間和濃度依賴性。然而，靛玉紅-3’-肟對正常細胞無顯著的細胞毒性作用。對其生長抑制作用機制的研究結果表明靛玉紅-3’-肟能夠特異性地減少LA-N-1細胞系中線粒體的調節子ERR和 PGC-1的表達，從而導致線粒體生成減少，線粒體膜電位降低以及線粒體活性氧（ROS）增加。靛玉紅-3’-肟還增加週期蛋白依賴性蛋白激酶（CDK）抑制蛋白p27{U+1D37}{U+2071}{U+1D56}¹的蛋白水平並降低週期蛋白依賴性蛋白激酶2（CDK2）和細胞週期蛋白E（Cyclin E）的表達，從而導致細胞週期阻滯在G0/G1期。 另外，我們發現靛玉紅-3’-肟能減少SH-SY5Y細胞系的線粒體生成，增加細胞內活性氧的水準從而導致細胞週期停滯在G0/G1期和細胞凋亡。以上結果表明靛玉紅-3’-肟可能通過破壞線粒體的功能從而導致LA-N-1和SH-SY5Y細胞的細胞週期阻滯和誘導SH-SY5Y細胞的細胞凋亡來發揮其抗腫瘤的作用。 / 接著，我們對色胺酮對人神經母細胞瘤的抗腫瘤活性和作用機制進行了探討。我們研究的結果表明，色胺酮可以時間和濃度依賴性地抑制人神經母細胞瘤LA-N-1, SH-SY5Y 和 SK-N-DZ細胞系的生長，而對正常的細胞無顯著的細胞毒性。對色胺酮抑制人神經母細胞瘤生長的機制研究表明，色胺酮能顯著地降低細胞週期蛋白（Cyclin D1和 Cyclin D3）和週期蛋白依賴性蛋白激酶（CDK4和CDK6）的蛋白水平從而導致細胞週期停滯在G0/G1期。色胺酮可以激活半胱氨酸天冬氨酸蛋白酶8,9和3/7（caspase 8, caspase 9 和 caspase 3/7）從而誘導LA-N-1細胞凋亡。色胺酮還可以誘導LA-N-1細胞分化，表現為神經細胞分化的細胞形態，乙醯膽鹼酯酶活性的增加和多種細胞分化的分子標記的表達上調。另外，色胺酮還能降低LA-N-1細胞中N-myc的表達。有趣的是，通過RNA干擾技術降低N-myc的表達能誘導LA-N-1細胞的分化。總的來說，以上結果顯示色胺酮通過誘導細胞週期阻滯，細胞凋亡和細胞分化從而發揮其抗腫瘤的作用。它可能被開發為治療有N-myc基因擴增的高危的人神經母細胞瘤的潛在藥物。 / 此外，我們還研究了靛玉紅-3’-肟和色胺酮是否具有抗血管生成的作用。體外實驗的研究結果表明，靛玉紅-3’-肟和色胺酮能夠濃度依賴性地抑制人微血管上皮細胞 （HMEC-1細胞）的增殖，遷徙和血管生成，但對HMEC-1細胞卻沒有顯著的細胞毒性作用。此外，靛玉紅-3’-肟和色胺酮能顯著地抑制小鼠體內的基質膠栓（Matrigel plug）的血管生成。對它們抑制血管生成的機制的研究表明，靛玉紅-3’-肟能下調血管生成素1（Ang-1）和基質金屬蛋白酶2（MMP2）的表達，上調血管生成素2（Ang-2）的表達。靛玉紅-3’-肟能結合到血管內皮生長因數受體2（VEGFR2） 的ATP結合位點上從而抑制血管內皮生長因數受體2的磷酸化和下游的MEK/ERK和PI3K/AKT/GSK信號轉導通路。色胺酮同樣可以抑制多種血管生成因子（Ang-1,PDGFB 和MMP2）的表達。此外，它可以結合到血管內皮生長因數受體2 的ATP結合位點上從而抑制血管內皮生長因數受體2的磷酸化和血管內皮生長因數受體2介導的ERK1/2信號通路。以上的體外和體內實驗研究結果表明靛玉紅-3’-肟和色胺酮通過靶向血管內皮生長因數受體2介導的信號通路來發揮其抗血管生成的作用。它們可能被開發為治療血管生成相關疾病的潛在藥物。 / 總而言之，我們的研究結果表明靛玉紅-3’-肟和色胺酮通過誘導人神經母細胞瘤細胞的細胞週期阻滯，細胞凋亡或誘導神經細胞分化從而抑制人神經母細胞瘤細胞的生長。然而，它們對正常細胞無顯著的細胞毒性作用。此外，靛玉紅-3’-肟和色胺酮通過靶向血管內皮生長因數受體2介導的信號通路來發揮其抗血管生成的作用。未來的研究將進一步探討靛玉紅-3’-肟和色胺酮對人神經母細胞瘤細胞的分子作用機理。另外，通過人神經母細胞瘤細胞的裸鼠移植瘤動物模型可進一步去了解這些板藍根生物鹼在體內的抗腫瘤效果。 / Neuroblastoma, a tumor of the sympathetic nervous system, is the most common extracranial solid cancer in childhood. It accounts for 8% to 10% of all childhood cancers and for approximately 15% of cancer deaths in children. Current treatment modalities consist of surgery, chemotherapy, radiation therapy, stem cell transplantation, differentiation therapy and immunotherapy. However, these treatments often cause severe and inevitable side effects. It is important to develop novel drugs with higher efficacy on neuroblastoma cells and minimal side effects on normal cells. The use of new promising therapeutic compounds derived from natural products or Chinese herbs have attracted much attention of scientist as an alternative strategy in cancer treatment. Indirubin-3’-oxime (I3M) is an indigo alkaloid and tryptanthrin is an indoloquinazoline alkaloid which can be isolated from the dried roots of medicinal indigo plants known as Banlangen. These two alkaloids have been reported to possess various biological and pharmacological activities, such as anti-microbial, anti-inflammatory, and anti-tumor effects. They were found to exhibit potent anti-tumor activities on various types of human cancer cells in vitro. However, their modulatory effects on human neuroblastoma and the underlying mechanisms remain poorly understood. In my PhD project, the possible anti-tumor activities and action mechanisms of Banlangen alkaloids, including I3M and tryptanthrin, on human neuroblastoma cells were investigated. / Firstly, the anti-cancer effects of I3M on human neuroblastoma cells and the underlying mechanisms were investigated. I3M was found to inhibit the growth of the human neuroblastoma LA-N-1, SH-SY5Y and SK-N-DZ cells in a concentration- and time-dependent manner, but exhibited little, if any, direct cytotoxicity on normal cells. Mechanistic studies showed that I3M specifically decreased the expression of mitochondrial regulators ERRγ and PGC-1βand resulted in decreased mitochondrial mass and altered mitochondrial function characterized by reduction in mitochondrial membrane potential and elevation of reactive oxygen species (ROS) level in LA-N-1 cells. I3M also increased the level of cyclin-dependent kinase (CDK) inhibitor p27{U+1D37}{U+2071}{U+1D56}¹ and reduced the levels of CDK2 and cyclin E in LA-N-1 cells, leading to cell cycle arrest at the G0/G1 phase. In addition, I3M was also found to reduce the mitochondrial mass and increase the ROS level leading to cell cycle arrest at G0/G1 phase and apoptosis in SH-SY5Y cells. These results, when taken together, suggest that I3M might exert its anti-tumor activity by causing mitochondrial dysfunction which led to cell cycle arrest in LA-N-1 cells and resulted in cycle arrest and apoptosis in SH-SY5Y cells. / The anti-tumor effects and action mechanisms of tryptanthrin on the human neuroblastoma cells were also examined. Our results showed that tryptanthrin inhibited the growth of the human neuroblastoma LA-N-1, SH-SY5Y and SK-N-DZ cells in a concentration- and time-dependent manner, but exhibited little, if any, direct cytotoxicity on normal cells. Mechanistic studies indicated that tryptanthrin significantly reduced the protein levels of cyclin D1, cyclin D3, CDK4 and CDK6 leading to cell cycle arrest at G0/G1 phase. In addition, tryptanthrin activated caspase 8, caspase 9 and caspase 3/7 resulting in apoptosis of the human neuroblastoma LA-N-1 cells. Moreover, tryptanthrin induced neuronal differentiation of LA-N-1 cells, as assessed by morphological criteria, enhancement of acetylcholine esterase activity and up-regulation of various differentiation markers. Tryptanthrin treatment also led to the significant reduction of N-myc expression in LA-N-1 cells. Interestingly, down-regulating N-myc expression using siRNA induced neuronal differentiation of LA-N-1 cells. Collectively, these results indicate that tryptanthrin might exert its anti-tumor activity on the human neuroblastoma LA-N-1 cells by inducing cell cycle arrest, apoptosis and neuronal differentiation. It might be exploited as a potential therapeutic candidate for the treatment of high-risk neuroblastomas with N-myc-amplification. / Moreover, the anti-angiogenic activities of I3M and tryptanthrin were studied. Our results showed that I3M and tryptanthrin inhibited the proliferation, migration, and tube formation of the human microvascular endothelial HMEC-1 cells in vitro in a concentration-dependent manner but exhibited no significant cytotoxicity on these cells. Moreover, I3M and tryptanthrin markedly suppressed the in vivo angiogenesis in Matrigel plugs in mice. Mechanistic studies indicated that I3M down-regulated the expression of Ang-1 and MMP2 and up-regulated the expression of Ang-2. It also bound to the ATP-binding site of VEGFR2 and inhibited the phosphorylation of VEGFR2 leading to suppression of the down-stream MEK/ERK and PI3K/AKT/GSK signaling pathways in HMEC-1 cells. Similarly, tryptanthrin also reduced the expression of several angiogenic factors (Ang-1, PDGFB and MMP2) in HMEC-1 cells. In addition, tryptanthrin also bound to the ATP-binding site of VEGFR2 and suppressed the phosphorylation of VEGFR2 and VEGFR2-mediated ERK1/2 signaling pathway in HMEC-1 cells. Collectively, our results demonstrated that I3M and tryptanthrin exhibited anti-angiogenic activity both in vitro and in vivo by specifically targeting the VEGFR2-mediated signaling pathways and might be exploited as potential therapeutic candidates for the treatment of angiogenesis-related diseases. / In conclusion, our findings indicate that I3M and tryptanthrin might exert their growth-inhibitory effect on the human neuroblastoma cells by causing cell cycle arrest, inducing apoptosis or inducing neuronal differentiation. However, they exhibited minimal cytotoxicity towards the normal cells. Moreover, I3M and tryptanthrin were found to possess anti-angiogenic activities by targeting the VEGFR2-mediated signaling pathways. In the future, investigations should be focused on further elucidation of the molecular action mechanisms of I3M and tryptanthrin on human neuroblastoma cells and to test the anti-tumor efficacy of I3M and tryptanthrin in animal models, using human neuroblastoma xenografts in nude mice. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Liao, Xuemei. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 206-229). / Abstract also in Chinese. / Acknowledgments --- p.i / Abbreviations --- p.ii / Publications --- p.vi / Abstract --- p.vii / 摘要 --- p.xii / Table of Contents --- p.xvi / Chapter One / General Introduction --- p.1 / Chapter 1.1 --- Neuroblastoma --- p.2 / Chapter 1.1.1 --- Epidemiology of neuroblastoma --- p.2 / Chapter 1.1.2 --- Classification of neuroblastoma --- p.6 / Chapter 1.1.3 --- Clinical symptoms and diagnosis of neuroblastoma --- p.10 / Chapter 1.1.4 --- Molecular pathogenesis of neuroblastoma --- p.13 / Chapter 1.1.4.1 --- Genetic alterations in neuroblastoma --- p.13 / Chapter 1.1.4.2 --- Disruption of cell division cycle, apoptotic and signaling pathways --- p.16 / Chapter 1.1.5 --- Treatment strategies --- p.19 / Chapter 1.1.5.1 --- Low-risk neuroblastoma treatment strategy --- p.19 / Chapter 1.1.5.2 --- Intermediate-risk neuroblastoma treatment strategy --- p.20 / Chapter 1.1.5.3 --- High-risk neuroblastoma treatment strategy --- p.21 / Chapter 1.1.5.4 --- Side effects of treatment --- p.23 / Chapter 1.2 --- Banlangen alkaloids --- p.23 / Chapter 1.2.1 --- Overview of Banlangen alkaloids --- p.23 / Chapter 1.2.2 --- Biological and pharmacological effects of Banlangen alkaloids --- p.28 / Chapter 1.2.2.1 --- Anti-inflammatory activity --- p.28 / Chapter 1.2.2.2 --- Anti-microbial activity --- p.29 / Chapter 1.2.2.3 --- Anti-tumor activity --- p.30 / Chapter 1.2.2.4 --- Other biological activities --- p.32 / Chapter 1.2.3 --- Bioavailability of Banlangen alkaloids --- p.33 / Chapter 1.2.4 --- Toxicity of Banlangen alkaloids --- p.34 / Chapter 1.3 --- Aims and scope of this project --- p.36 / Chapter Two / Materials and Methods --- p.38 / Chapter 2.1 --- Materials --- p.39 / Chapter 2.1.1 --- Animals --- p.39 / Chapter 2.1.2 --- Cell lines --- p.39 / Chapter 2.1.3 --- Cell culture media --- p.41 / Chapter 2.1.4 --- Drugs and chemicals --- p.42 / Chapter 2.1.5 --- Reagents and buffers for cell culture --- p.44 / Chapter 2.1.6 --- General staining solutions --- p.47 / Chapter 2.1.7 --- Reagents and buffers for cell growth assays --- p.48 / Chapter 2.1.8 --- Reagents and buffers for flow cytometry --- p.48 / Chapter 2.1.9 --- Reagents and buffers for acetylcholine esterase activity assay --- p.50 / Chapter 2.1.10 --- Reagents and buffers for immunocytochemistry --- p.51 / Chapter 2.1.11 --- Reagents and buffers for total RNA extraction --- p.53 / Chapter 2.1.12 --- Reagents and buffers for reverse transcription --- p.54 / Chapter 2.1.13 --- Reagents for quantitative real-time polymerase chain reaction (qRT-PCR) --- p.56 / Chapter 2.1.14 --- Reagents and buffers for Western blotting --- p.59 / Chapter 2.1.15 --- Assay kits --- p.65 / Chapter 2.2 --- Methods --- p.68 / Chapter 2.2.1 --- Culture of cells --- p.68 / Chapter 2.2.2 --- MTT assay --- p.69 / Chapter 2.2.3 --- Cell proliferation assay --- p.70 / Chapter 2.2.4 --- Trypan blue exclusion test --- p.70 / Chapter 2.2.5 --- Cytotoxicity assay --- p.71 / Chapter 2.2.6 --- Colony-forming assay --- p.72 / Chapter 2.2.7 --- Cell cycle analysis --- p.72 / Chapter 2.2.8 --- Assessment of apoptosis --- p.73 / Chapter 2.2.9 --- Caspase activity determination --- p.74 / Chapter 2.2.10 --- Mitochondrial mass assay --- p.75 / Chapter 2.2.11 --- Reactive oxygen species (ROS) assay --- p.75 / Chapter 2.2.12 --- Mitochondrial membrane potential determination --- p.76 / Chapter 2.2.13 --- Morphological detection of cell differentiation --- p.76 / Chapter 2.2.14 --- Acetylcholine esterase activity determination --- p.77 / Chapter 2.2.15 --- Immunocytochemistry --- p.77 / Chapter 2.2.16 --- RNA interference --- p.78 / Chapter 2.2.17 --- Wound healing assay --- p.79 / Chapter 2.2.18 --- Tube formation assay --- p.79 / Chapter 2.2.19 --- In vivo Matrigel plug assay --- p.80 / Chapter 2.2.20 --- Phospho-VEGFR2 Sandwich ELISA assay --- p.80 / Chapter 2.2.21 --- Isolation of total cellular RNA --- p.81 / Chapter 2.2.22 --- Reverse transcription (RT) --- p.82 / Chapter 2.2.23 --- Quantitative real-time PCR --- p.83 / Chapter 2.2.24 --- Total protein extraction --- p.84 / Chapter 2.2.25 --- Protein concentration determination --- p.84 / Chapter 2.2.26 --- Sodium dodecyl sulphate-Polyacrylamide gel electrophoresis (SDS-PAGE) --- p.85 / Chapter 2.2.27 --- Semi-dry Western blotting --- p.85 / Chapter 2.2.28 --- Enhanced chemiluminescence (ECL) assay --- p.87 / Chapter 2.2.29 --- Molecular docking --- p.87 / Chapter 2.2.30 --- Statistical analysis --- p.88 / Chapter Three / Modulatory effects and action mechanisms of indirubin-3'-oxime on human neuroblastoma cells --- p.89 / Chapter 3.1 --- Introduction --- p.90 / Chapter 3.2 --- Results --- p.94 / Chapter 3.2.1 --- Indirubin-3’-oxime inhibited the growth and colony formation of human neuroblastoma cells in vitro --- p.94 / Chapter 3.2.2 --- Indirubin-3’-oxime exhibited no significant cytotoxicity on normal cells --- p.101 / Chapter 3.2.3 --- Indirubin-3’-oxime induced G0/G1 cell cycle arrest in LA-N-1 cells --- p.103 / Chapter 3.2.4 --- Indirubin-3’-oxime caused mitochondrial dysfunction in LA-N-1 cells --- p.106 / Chapter 3.2.5 --- Indirubin-3’-oxime selectively reduced ERR γ and PGC-1β protein and mRNA levels in LA-N-1 cells --- p.111 / Chapter 3.2.6 --- Indirubin-3’-oxime induced cell cycle arrest at G0/G1 phase and apoptosis of SH-SY5Y cells --- p.113 / Chapter 3.2.7 --- Indirubin-3’-oxime reduced mitochondrial mass and elevated mitochondrial ROS level in SH-SY5Y cells --- p.115 / Chapter 3.2.8 --- Indirubin-3’-oxime increased the caspase 8, caspase 9 and caspase 3/7 activities in SH-SY5Y cells --- p.117 / Chapter 3.3 --- Discussion --- p.119 / Chapter Four / Modulatory effects and action mechanisms of tryptanthrin on human neuroblastoma cells --- p.125 / Chapter 4.1 --- Introduction --- p.126 / Chapter 4.2 --- Results --- p.129 / Chapter 4.2.1 --- Tryptanthrin inhibited the cell growth and colony formation of human neuroblastoma cells --- p.129 / Chapter 4.2.2 --- Tryptanthrin exhibited no significant cytotoxicity on normal cells --- p.136 / Chapter 4.2.3 --- Tryptanthrin induced cell cycle arrest at G0/G1 phase --- p.138 / Chapter 4.2.4 --- Tryptanthrin induced apoptosis of LA-N-1 cells --- p.140 / Chapter 4.2.5 --- Tryptanthrin induced morphological neuronal differentiation in LA-N-1 cells --- p.143 / Chapter 4.2.6 --- Tryptanthrin induced the expression of neuronal differentiation markers --- p.146 / Chapter 4.2.7 --- Tryptanthrin down-regulated the expression of N-myc in LA-N-1 cells --- p.149 / Chapter 4.3 --- Discussion --- p.152 / Chapter Five / Anti-angiogenesis effects and action mechanisms of indirubin-3'-oxime and tryptanthrin --- p.158 / Chapter 5.1 --- Introduction --- p.159 / Chapter 5.2 --- Results --- p.163 / Chapter 5.2.1 --- Indirubin-3’-oxime and tryptanthrin inhibited the proliferation of endothelial cells --- p.163 / Chapter 5.2.3 --- Indirubin-3’-oxime and tryptanthrin reduced the tube formation of endothelial cells --- p.168 / Chapter 5.2.4 --- Indirubin-3’-oxime and tryptanthrin blocked angiogenesis in the in vivo Matrigel plug model --- p.171 / Chapter 5.2.5 --- Indirubin-3’-oxime and tryptanthrin reduced the angiogenic gene expression in endothelial cells --- p.174 / Chapter 5.2.6 --- Indirubin-3’-oxime and tryptanthrin attenuated VEGFR2-mediated signaling pathways in endothelial cells --- p.176 / Chapter 5.2.7 --- Indirubin-3’-oxime bound to the ATP-binding site of VEGFR2 kinase domain --- p.181 / Chapter 5.2.8 --- Tryptanthrin bound to the ATP-binding site of VEGFR2 kinase domain --- p.182 / Chapter 5.3 --- Discussion --- p.184 / Chapter Six / Conclusions and future perspectives --- p.191 / References --- p.206

Yip, Hon Yan Kelvin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 218-242). / Abstracts in English and Chinese. / ACKNOWLEDGEMENTS --- p.i / ABBREVIATIONS --- p.ii / ABSTRACT --- p.vii / CHINESE ABSTRACT (摘要） --- p.xi / PUBLICATIONS --- p.xiv / TABLE OF CONTENTS --- p.xv / Chapter CHAPTER 1: --- GENERAL INTRODUCTION --- p.1 / Chapter 1.1 --- Neuroblastoma --- p.2 / Chapter 1.1.1 --- An overview of neuroblastoma --- p.2 / Chapter 1.1.2 --- Epidemiology of neuroblastoma --- p.3 / Chapter 1.1.3 --- Clinical presentations of neuroblastoma --- p.5 / Chapter 1.1.4 --- Diagnosis and clinical assessment of neuroblastoma --- p.8 / Chapter 1.1.5 --- Staging of neuroblastoma --- p.10 / Chapter 1.1.6 --- Genetic aberrations of neuroblastoma --- p.12 / Chapter 1.1.7 --- Therapies of neuroblastoma --- p.15 / Chapter 1.2 --- Banlangen alkaloids --- p.20 / Chapter 1.2.1 --- An overview of Banlangen alkaloids --- p.20 / Chapter 1.2.2 --- "Pharmacokinetics of indirubin, tryptanthrin and their derivatives" --- p.24 / Chapter 1.2.2.1 --- Bioavailability of indirubin and its derivatives --- p.24 / Chapter 1.2.2.2 --- Toxicity of indirubin and its derivatives --- p.25 / Chapter 1.2.2.3 --- Bioavailability of tryptanthrin --- p.26 / Chapter 1.2.2.4 --- Toxicity of tryptanthrin --- p.27 / Chapter 1.2.3 --- "Pharmacological effects of indirubin, tryptanthrin and their derivatives" --- p.28 / Chapter 1.2.3.1 --- Selective inhibitor on kinases --- p.29 / Chapter 1.2.3.2 --- Anti-inflammatory activities --- p.31 / Chapter 1.2.3.3 --- Anti-tumour activities --- p.32 / Chapter 1.2.3.3.1 --- Anti-leukemic activity --- p.32 / Chapter 1.2.3.3.2 --- Apoptosis-inducing activity --- p.34 / Chapter 1.2.3.4 --- Anti-viral properties --- p.37 / Chapter 1.2.3.5 --- Anti-microbial properties --- p.37 / Chapter 1.3 --- Aims and Scope of This Study --- p.39 / Chapter CHAPTER 2: --- MATERIALS AND METHODS --- p.41 / Chapter 2.1 --- Materials --- p.42 / Chapter 2.1.1 --- Cell lines --- p.42 / Chapter 2.1.2 --- "Cell culture media, reagents and buffers" --- p.43 / Chapter 2.1.3 --- General staining solutions --- p.46 / Chapter 2.1.4 --- Drugs and chemicals --- p.47 / Chapter 2.1.5 --- Reagent for primary cultures preparation --- p.48 / Chapter 2.1.6 --- Reagents for cell proliferation assay --- p.48 / Chapter 2.1.7 --- Reagents for DNA extraction --- p.50 / Chapter 2.1.8 --- Reagents for gel electrophoresis of nucleic acids --- p.51 / Chapter 2.1.9 --- Reagents and buffers for flow cytometry --- p.53 / Chapter 2.1.10 --- Reagents and buffers for measuring caspase activity --- p.54 / Chapter 2.1.11 --- "Reagents, buffers and materials for Western blot analysis" --- p.58 / Chapter 2.1.12 --- Reagent for Hoechst staining --- p.68 / Chapter 2.2 --- Methods --- p.69 / Chapter 2.2.1 --- Culture of cell lines --- p.69 / Chapter 2.2.2 --- Determination of cell viability --- p.70 / Chapter 2.2.3 --- Determination of cell proliferation by tritiated thymidine ([ 3H]-TdR) incorporation assay --- p.72 / Chapter 2.2.4 --- "Isolation, culture and cytotoxicity test of murine peritoneal macrophages" --- p.73 / Chapter 2.2.5 --- "Isolation, culture and cytotoxicity test of murine bone marrow cells" --- p.74 / Chapter 2.2.6 --- Cytotoxicity test of primary cortical neurons from SD rats --- p.75 / Chapter 2.2.7 --- Determination of colony forming ability --- p.75 / Chapter 2.2.8 --- Analysis of cell cycle profile /DNA content by flow cytometry --- p.76 / Chapter 2.2.9 --- Detection of DNA fragmentation by agarose gel electrophoresis --- p.77 / Chapter 2.2.10 --- Quantitative detection of DNA fragmentation by Cell Death ELISAplus kit --- p.78 / Chapter 2.2.11 --- Detection of intracellular reactive oxygen species (ROS) generation --- p.80 / Chapter 2.2.12 --- Measurement of caspase activity --- p.81 / Chapter 2.2.13 --- Hoechst 33342 staining --- p.83 / Chapter 2.2.14 --- Cell morphological study --- p.83 / Chapter 2.2.15 --- Analysis of morphological changes by flow cytometry --- p.84 / Chapter 2.2.16 --- Assay for acetylcholine esterase (AChE) activity --- p.85 / Chapter 2.2.17 --- Protein expression study --- p.86 / Chapter 2.2.18 --- Statistical analysis --- p.89 / Chapter CHAPTER 3: --- IN VITRO STUDIES ON THE ANTI PROLIFERATIVE EFFECT OF INDIRUBIN-3'-OXIME AND TRYPTANTHRIN ON NEUROBLASTOMA CELLS --- p.90 / Chapter 3.1 --- Introduction --- p.91 / Chapter 3.2 --- Results --- p.95 / Chapter 3.2.1 --- Effects of indirubin-3'-oxime and tryptanthrin on the proliferation of human and the murine neuroblastoma cells --- p.95 / Chapter 3.2.2 --- Kinetic and reversibility studies of the anti-proliferative effect of indirubin-3'-oxime and tryptanthrin on the murine neuroblastoma Neuro-2a BU-1 cells --- p.107 / Chapter 3.2.3 --- Cytotoxic effect of indirubin-3'-oxime and tryptanthrin on the murine neuroblastoma Neuro-2a BU-1 cells --- p.115 / Chapter 3.2.4 --- Effects of indirubin-3'-oxime and tryptanthrin on the clonogenicity of the murine neuroblastoma Neuro-2a BU-1 cells --- p.120 / Chapter 3.2.5 --- Cytotoxicity of indirubin-3'-oxime and tryptanthrin on primary cells --- p.123 / Chapter 3.2.6 --- Effects of tryptanthrin on the cell cycle profile and expression of cyclins and cyclin-dependent kinases (CDKs) in the murine neuroblastoma Neuro-2a BU-1 cells --- p.132 / Chapter 3.2.7 --- Effect of indirubin-3'-oxime on the cell cycle profile in the murine neuroblastoma Neuro-2a BU-1 cells --- p.133 / Chapter 3.3 --- Discussion --- p.142 / Chapter CHAPTER 4: --- IN VITRO STUDIES ON THE APOPTOSIS-INDUCING EFFECT OF INDIRUBIN-3'-OXIME ON NEUROBLASTOMA CELLS --- p.150 / Chapter 4.1 --- Introduction --- p.151 / Chapter 4.2 --- Results --- p.156 / Chapter 4.2.1 --- Induction of DNA fragmentation in the indirubin-3'-oxime-treated murine neuroblastoma Neuro-2a BU-1 cells --- p.156 / Chapter 4.2.2 --- Induction of chromatin condensation in the indirubin-3 '-oxime-treated murine neuroblastoma Neuro-2a BU-1 cells --- p.160 / Chapter 4.2.3 --- Induction of caspase activities in the indirubin-3 '-oxime-treated murine neuroblastoma Neuro-2a BU-1 cells --- p.162 / Chapter 4.2.4 --- Induction of Reactive Oxygen Species (ROS) in the indirubin-3' -oxime-treated murine neuroblastoma Neuro-2a BU-1 cells --- p.169 / Chapter 4.2.5 --- Expression of pro-apoptotic and anti-apoptotic proteins in the indirubin-3 '-oxime-treated murine neuroblastoma Neuro-2a BU-1 cells --- p.173 / Chapter 4.3 --- Discussion --- p.177 / Chapter CHAPTER 5: --- STUDIES ON THE DIFFERENTIATION-INDUCING ACTIVITY OF TRYPTANTHRIN ON NEUROBLASTOMA CELLS --- p.188 / Chapter 5.1 --- Introduction --- p.189 / Chapter 5.2 --- Results --- p.193 / Chapter 5.2.1 --- Effects of tryptanthrin on the cell size and cellular complexity of the murine neuroblastoma Neuro-2a BU-1 cells --- p.193 / Chapter 5.2.2 --- Morphological studies on tryptanthrin-treated murine neuroblastoma Neuro-2a BU-1 cells --- p.196 / Chapter 5.2.3 --- Effect of tryptanthrin on the acetylcholine esterase (AChE) activity in the murine neuroblastoma Neuro-2a BU-1 cells --- p.198 / Chapter 5.2.4 --- Effects of tryptanthrin on the expression of tau protein and other mediators involved in the differentiation pathway --- p.200 / Chapter 5.3 --- Discussion --- p.204 / Chapter CHAPTER 6: --- CONCLUSIONS AND FUTURE PERSPECTIVES --- p.209 / REFERENCES --- p.218

Neuroblastoma (NB) is the most common solid tumor of early infancy. Despite a significant improvement in the general survival rate for children with cancer, the prognosis of high-risk NB remains low, at about 30%, despite the use of intensive chemo-radiotherapy followed by differentiation therapy with retinoic acid (RA). Relapses in this category of NB are often due to the emergence of multi-drug and RA-resistant minimal residual cancer cells. The use of natural 13-cis RA, as a single chemo-preventive agent, has improved the survival rate to 50% for high-risk NB patients. However, the prevalence of RA-resistance is high in high-risk NB, and in solid cancers, in general. RA-resistance in cancer cells is mediated by a number of factors. Loss of RA-induced expression of the putative tumor suppressor gene, retinoic acid receptor-beta (RARβ), is one of the most common factors that have been reported in RAresistant phenotypes of a wide range of cancer cells. The transcriptional regulation of RAR(β) gene and other retinoid responsive-genes is believed to be regulated by the ligand-dependent transactivation of the homo- or heterodimer complexes of the retinoic acid receptor (RAR) and retinoid X receptor (RXR) subtypes, namely alpha (α), beta (β) and gamma (γ). It is believed that the anti-cancer activities of natural all-trans RA and 13-cis RA are mediated through activation of RAR-complexes. The loss of RA-induced RAR β expression can be caused by aberrant recruitment of chromatin structure modifying enzymes, histone deacetylases (HDACs), which have major roles in the global regulation of gene transcription. However, the mechanism of RA-resistance in NB cells is unclear. This thesis set out to identify the molecular mechanism of RA-resistance and to develop a new therapeutic approach to overcome RA-resistance in NB cells. The data in this thesis demonstrated that deregulation or over-expression of proto-oncogene MYCN caused a total RA-resistance in NB cells in vitro and in vivo, despite the strong induction of RARI3 expression. The data also indicated that the activation of RAR-dependent pathways by aRA or 13RA alone is not sufficient to overcome MYCN-mediated RA-resistance in NB cells. In the light of this observation, this thesis went on to examine whether combined targeting activation of RAR and RXR subtypes with receptor specific ligands could enhance the therapeutic efficacy of the retinoid signaling pathway. NB cells were treated with a panel of receptor-specific retinoids, namely aRA, l3RA, 9RA (RAR-specific), CD 417, CD 2314 (RARβ-specific), CD 666 (RARγ-specific), CD 336 (RARα-specific), CD 3640, CD 2872 (RXR-specific), as a single agent or in combination at a low concentration of 0.1 ??M. The results showed that combined targeting activation of RARα and RXR was not only the most effective combination, but also overcame MYCN-mediated RA-resistance in NB cells in vitro.Collectively, these data demonstrated the combined targeting activation of RAR and RXRs as a new approach to enhance the efficacy of retinoid therapy and overcome RA-resistance in the treatment of high-risk NB, and other cancers. The emerging therapeutic potential of HDAC inhibitors (HDACi) as front line anti-cancer agents, or adjuvants to other agents such as RA, has suggested a new approach in the treatment of cancer. However, the molecular mechanism of the remarkably specific anticancer actions of HDACi is still largely speculation. The data presented in this study was the first to demonstrate a novel sequential order and the dosage-dependent roles of basal p21Wafl expression and G2/M arrest as protective mechanisms against HDACi-induced apoptosis. In addition, this thesis also examined and compared the therapeutic efficacy of HDACi as a single agent and in combination with other anti-cancer agents such as RA, IFNα and chemotherapeutic agents. Evaluation of the therapeutic effects of combinations of aRA, IFN and HDACi showed that combination of HDACi and IFNα exhibited the strongest synergy against NB cells in vitro. Treatment of MYCN transgenic mice, which consistently develop abdominal NB tumors that closely mirror the human disease in both physiological and biological aspects, with hydroxamic acid-based HDACi, trichostatin A (TSA), alone reduced tumor growth by nearly 50%, compared to the solvent control and IFNα alone, which had no effect on NB tumor growth. The most exciting finding was that the combination of HDACi and IFNα synergistically reduced tumor mass and angiogenesis by over 80% without any apparent systemic side-effects. The therapeutic effect of treatment with HDACi correlated with the induction of acetylation of histone 4 protein (H4) in both tumor and organ tissues, indicating a wide therapeutic index for HDACi in vivo. Collectively, the data in this study have demonstrated basal p21 Wafl expression as a potential marker of sensitivity to HDACi-based therapy, and the therapeutic efficacy of a novel combination of HDACi with IFNα in vivo. These preclinical data have provided an evidence-based rationale for a clinical trial of the combination of HDACi and IFNα in the treatment of high risk NB.

Ho, Lai Ying. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 213-238). / Abstract also in Chinese. / Abstract --- p.i / Abstract in Chinese (摘要） --- p.iv / Acknowledgements --- p.vii / List of abbreviations --- p.ix / Table of contents --- p.xiv / Chapter Chapter One: --- General Introduction_ --- p.1 / Chapter 1.1 --- Neuroblastoma --- p.2 / Chapter 1.1.1 --- An overview on neuroblastoma --- p.2 / Chapter 1.1.2 --- Classification of neuroblastoma --- p.4 / Chapter 1.1.3 --- Epidemiology of neuroblastoma --- p.7 / Chapter 1.1.4 --- Clinical manifestation of neuroblastoma --- p.10 / Chapter 1.1.5 --- Diagnosis of neuroblastoma --- p.10 / Chapter 1.1.6 --- Conventional therapy of neuroblastoma --- p.12 / Chapter 1.1.7 --- Novel treatments of neuroblastoma --- p.14 / Chapter 1.2 --- Conjugated linolenic acid (CLN) --- p.16 / Chapter 1.2.1 --- An overview of polyunsaturated fatty acids and conjugated fatty acids --- p.16 / Chapter 1.2.2 --- Chemical structure and physical properties of CLNs --- p.18 / Chapter 1.2.3 --- Natural occurrence of CLNs --- p.21 / Chapter 1.2.4 --- Synthesis of CLNs --- p.22 / Chapter 1.2.5 --- Metabolism and pharmacokinetics of CLNs --- p.24 / Chapter 1.2.6 --- Major biological and pharmacological activities of CLNs --- p.25 / Chapter 1.2.6.1 --- Hypolipidemic and anti-obese effects --- p.25 / Chapter 1.2.6.2 --- Anti-cancer effects --- p.27 / Chapter 1.2.6.2.1 --- Anti-proliferation --- p.27 / Chapter 1.2.6.2.2 --- Chemoprevention --- p.28 / Chapter 1.2.6.2.3 --- Apoptosis-inducing --- p.28 / Chapter 1.3 --- Aims and scope of the study --- p.31 / Chapter Chapter Two: --- Materials and Methods_ --- p.34 / Chapter 2.1 --- Materials --- p.35 / Chapter 2.1.1 --- Animals --- p.35 / Chapter 2.1.2 --- Cell lines --- p.35 / Chapter 2.1.3 --- "Cell culture medium, buffers and other reagents" --- p.37 / Chapter 2.1.4 --- Reagents for DNA extraction --- p.46 / Chapter 2.1.5 --- Reagents for gel electrophoresis of nucleic acids --- p.47 / Chapter 2.1.6 --- Reagents and buffers for flow cytometry --- p.49 / Chapter 2.1.7 --- Reagents and buffers for measuring caspase activity --- p.50 / Chapter 2.1.8 --- Reagents for Hoechst staining --- p.53 / Chapter 2.1.9 --- Reagents and buffers for RNA extraction --- p.53 / Chapter 2.1.10 --- Reagents and buffers for DNA digestion --- p.54 / Chapter 2.1.11 --- Reagents and buffers for reverse transcription --- p.55 / Chapter 2.1.12 --- Reagents for real-time polymerase chain reaction --- p.57 / Chapter 2.1.13 --- Reagents and buffers for Western blotting --- p.59 / Chapter 2.2 --- Methods --- p.64 / Chapter 2.2.1 --- Culture of cell lines --- p.64 / Chapter 2.2.2 --- Preparation of NIH-3T3 conditioned medium --- p.65 / Chapter 2.2.3 --- Determination of cell viability --- p.65 / Chapter 2.2.4 --- Determination of cell proliferation by tritiated thymidine incorporation assay --- p.66 / Chapter 2.2.5 --- Cytotoxicity test of CLNs on murine peritoneal macrophages --- p.67 / Chapter 2.2.6 --- Cytotoxicity test of CLNs on murine bone marrow cells --- p.68 / Chapter 2.2.7 --- Cytotoxicity test of CLNs on murine splenocytes --- p.68 / Chapter 2.2.8 --- Cytotoxicity tests of CLNs on human peripheral blood mononuclear cells --- p.69 / Chapter 2.2.9 --- Carboxyfluorescein diacetate succinimidyl ester (CFSE) staining analyzed by flow cytometry --- p.69 / Chapter 2.2.10 --- Determination of colony forming ability --- p.70 / Chapter 2.2.11 --- Determination of cell invasiveness --- p.70 / Chapter 2.2.12 --- In vivo tumorigenicity assay --- p.71 / Chapter 2.2.13 --- Analysis of cell cycle profile/ DNA content by flow cytometry --- p.72 / Chapter 2.1.14 --- Measurements of apoptosis --- p.72 / Chapter 2.1.15 --- Measurements of differentiation --- p.77 / Chapter 2.1.16 --- Gene expression study --- p.78 / Chapter 2.2.17 --- Protein expression study --- p.81 / Chapter 2.2.18 --- Statistical Analysis --- p.84 / Chapter Chapter Three: --- Anti-proliferative Effect of CLN Isomers on Human Neuroblastoma cells --- p.86 / Chapter 3.1 --- Introduction --- p.87 / Chapter 3.2 --- Results --- p.89 / Chapter 3.2.1 --- Anti-proliferative effect of CLN isomers on various human neuroblastoma cell lines in vitro --- p.89 / Chapter 3.2.2 --- Direct cytotoxic effect of jacaric acid on neuroblastoma LA-N-1 cells in vitro --- p.100 / Chapter 3.2.3 --- Cytotoxicity of jacaric acid on primary murine cells and human normal cell lines --- p.103 / Chapter 3.2.4 --- Kinetic and reversibility studies of the anti-proliferative effect of jacaric acid on LA-N-1 cells --- p.106 / Chapter 3.2.5 --- Synergistic anti-proliferative effect of jacaric acid with daidzein and retinoic acid on LA-N-1 cells in vitro --- p.110 / Chapter 3.2.6 --- Modulatory effect of jacaric acid on the number of cell division in LA-N-1 cells --- p.113 / Chapter 3.2.7 --- Effect of jacaric acid on the cell cycle profile of LA-N-1 cells --- p.115 / Chapter 3.2.8 --- Effect of jacaric acid on the invasiveness of LA-N-1 cells --- p.118 / Chapter 3.2.9 --- Effect of jacaric acid on the colony forming ability of LA-N-1 cells in soft agar --- p.120 / Chapter 3.2.10 --- Effect of jacaric acid on the in vivo tumorigenicity of the LA-N-1 cells --- p.122 / Chapter 3.3 --- Discussion --- p.124 / Chapter Chapter Four: --- Apoptosis- and Differentiation-inducing Effects of Jacaric Acid on Human Neuroblastoma Cells --- p.133 / Chapter 4.1 --- Introduction --- p.134 / Chapter 4.2 --- Results --- p.138 / Chapter 4.2.1 --- Induction of DNA fragmentation and apoptotic ultrastructural changes in LA-N-1 cells by jacaric acid --- p.138 / Chapter 4.2.2 --- Induction of phosphatidylserine externalization by jacaric acid in human neuroblastoma cells as detected by Annexin V-GFP/ PI dual staining --- p.142 / Chapter 4.2.3 --- Effect of jacaric acid on the mitochondrial membrane potential in human neuroblastoma cells --- p.146 / Chapter 4.2.4 --- Effect of jacaric acid on the caspase-3 activity in LA-N-1 cells --- p.150 / Chapter 4.2.5 --- Effect of jacaric acid on the reactive oxygen species (ROS) generation in human neuroblastoma cells --- p.153 / Chapter 4.2.6 --- Morphological changes induced by jacaric acid in SH-SY5Y cells --- p.158 / Chapter 4.3 --- Discussion --- p.162 / Chapter Chapter Five: --- Mechanistic Studies of Anti-proliferative Effect of Jacaric Acid on Human Neuroblastoma Cells --- p.171 / Chapter 5.1 --- Introduction --- p.172 / Chapter 5.2 --- Results --- p.178 / Chapter 5.2.1 --- Effect of antioxidant a-tocopherol on the anti-proliferative effect of jacaric acid on LA-N-1 cells --- p.178 / Chapter 5.2.2 --- Effect of caspase inhibitors on the anti-proliferative effect of jacaric acid on LA-N-1 cells --- p.180 / Chapter 5.2.3 --- Jacaric acid modulated the mRNA expression of N-myc and other related transcription factors in LA-N-1 cells --- p.182 / Chapter 5.2.4 --- Jacaric acid modulated the protein expression of N-myc --- p.186 / Chapter 5.2.5 --- Jacaric acid modulated the mRNA expression of apoptosis-associated genes --- p.188 / Chapter 5.3 --- Discussion --- p.191 / Chapter Chapter Six: --- Conclusions and Future Perspectives --- p.202 / References --- p.212