Leung Kam Tong. / Thesis submitted in: September 2006. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 79-95). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (Chinese) --- p.iii / Acknowledgements --- p.v / Table of contents --- p.vi / List of figures --- p.ix / List of abbreviations --- p.xii / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter 1.1 --- Acute lymphoblastic leukemia --- p.1 / Chapter 1.2 --- T-cell acute lymphoblastic leukemia --- p.2 / Chapter 1.2.1 --- Chemotherapy --- p.2 / Chapter 1.2.1.1 --- Induction therapy --- p.2 / Chapter 1.2.1.2 --- Intensification therapy --- p.3 / Chapter 1.2.1.3 --- Maintenance therapy --- p.3 / Chapter 1.2.2 --- Chemoresistance in T-ALL --- p.3 / Chapter 1.3 --- Apoptosis and chemoresistance --- p.5 / Chapter 1.3.1 --- "Initiation, execution and regulation of apoptosis" --- p.5 / Chapter 1.3.1.1 --- Initiation of apoptosis --- p.5 / Chapter 1.3.1.2 --- Execution of apoptosis --- p.7 / Chapter 1.3.1.3 --- Regulation of apoptosis --- p.7 / Chapter 1.3.2 --- Mechanisms of resistance to apoptosis --- p.9 / Chapter 1.3.2.1 --- Overexpression of pro-survival proteins --- p.9 / Chapter 1.3.2.2 --- Downregulation and mutation of pro-apoptotic proteins --- p.11 / Chapter 1.3.2.3 --- Other mechanisms --- p.13 / Chapter 1.4 --- Bcl-2 interating mediator of cell death --- p.14 / Chapter 1.4.1 --- Role of Bim in apoptosis --- p.16 / Chapter 1.4.2 --- Regulation of Bim --- p.17 / Chapter 1.4.2.1 --- Transcriptional regulation of Bim --- p.18 / Chapter 1.4.2.2 --- Post-transcriptional regulation of Bim --- p.18 / Chapter 1.5 --- c-Jun N-terminal kinase --- p.20 / Chapter 1.5.1 --- Pro-apoptotic role of JNK --- p.21 / Chapter 1.5.2 --- Anti-apoptotic role of JNK --- p.21 / Chapter 1.6 --- Hypotheses --- p.22 / Chapter Chapter 2 --- Materials and Methods --- p.23 / Chapter 2.1 --- Cell culture --- p.23 / Chapter 2.2 --- Induction of quantification of apoptosis --- p.24 / Chapter 2.3 --- Determination of caspase activities --- p.24 / Chapter 2.4 --- Western blotting --- p.25 / Chapter 2.4.1 --- Protein extraction and determination of protein concentration --- p.25 / Chapter 2.4.2 --- SDS-PAGE and immunodetection --- p.26 / Chapter 2.5 --- Cell-free apoptosis reactions --- p.27 / Chapter 2.6 --- Analysis of mitochondrial membrane potential --- p.27 / Chapter 2.7 --- Transient transfection of Sup-Tl cells --- p.28 / Chapter 2.8 --- Reverse transcription-polymerase chain reaction (RT-PCR) --- p.28 / Chapter 2.8.1 --- RNA isolation --- p.28 / Chapter 2.8.2 --- Synthesis of first-strand cDNA --- p.29 / Chapter 2.8.3 --- Polymerase chain reaction --- p.29 / Chapter 2.9 --- Alkaline phosphatase digestion of Bim --- p.30 / Chapter Chapter 3 --- Results --- p.31 / Chapter 3.1 --- The T-ALL cell line Sup-Tl is resistant to etoposide-induced apoptosis --- p.31 / Chapter 3.2 --- Sup-Tl cells are resistant to etoposide-induced caspase activation --- p.40 / Chapter 3.3 --- Sup-Tl cells are insusceptible to etoposide-induced mitochondrial alterations --- p.46 / Chapter 3.4 --- BimEL is required for etoposide-induced apoptosis in Sup-Tl cells --- p.51 / Chapter 3.5 --- The reduced level of BimEL in Sup-Tl cells is owing to the presence of constitutively active JNK --- p.58 / Chapter Chapter 4 --- Discussion --- p.67 / References --- p.79