Relapsed ALL remams one of the most common causes of death from disease in children. Broad-range drug resistance is often associated with relapse, although its underlying molecular mechanisms remained poorly understood. The aim of this thesis was to establish an in vivo model using the non-obese diabetic/severe combined immunodeficient (NOD/SCID) mouse strain, to facilitate the engraftment, expansion and characterisation of childhood ALL cells, obtained from patients at diagnosis or relapse. Mice were inoculated with leukaemia cells from patients' biopsies and engraftment was monitored by the proportion of human CD45+ cells in the blood. Successful leukaemia engraftment was achieved for 20/20 patient biopsies. Continuous passaging of ten xenografts has also been achieved. Immunophenotypic analysis showed only minor changes in cell surface markers after passage in mice. Leukaemia dissemination in murine bone marrow, liver, spleen and blood was consistent with the human disease. The in vivo responses of ten continuous xenografts to dexamethasone and vincristine, but not methotrexate, significantly correlated with patient outcome (p<0.05). Xenograft sub-lines resistant to vincristine, dexamethasone, methotrexate and cytosine arabinoside were also selected by in vivo drug treatments, although these sublines were not found to be cross resistant to structurally unrelated drugs. Resistance to vincristine, either in in vivo selected sub-lines or inherently resistant xenografts, was not associated with increased activity of drug efflux pumps such as P-gp or MRPl. Class I ?? tubulin levels remained unchanged when compared between vincristine resistant sublines and their parental xenografts. Decreased expression of stathmin and increased polymerised tubulin were observed in vincristine resistant sub-lines, suggesting a possible mechanism of counteracting the depolymerising effects of vincristine. In summary, this study has shown that primary ALL cells engraft efficiently into NOD/SCID mice, and indicates that their response to vincristine and dexamethasone mimics the clinical situation. This model appears to be highly relevant for the study of childhood ALL and will provide the foundation to delineate clinically relevant mechanisms of drug resistance.

Long-term survival and probable cure have become norms in acute lymphoblastic leukaemia of childhood. The adverse effects of treatment for leukaemia are diverse and complex. In many cases, treatment effects come to light 1 ong after the end of therapy. These so-ca 11 ed 1 ate effects (which are yet obscure and incompletely understood) have become increasingly important as the number of children surviving leukaemia increases. This thesis describes a comprehensive study of leukaemia survivors attending the Oncology Clinic of the Red Cross War Memorial Children's Hospital. The study sample consisted of all leukaemia survivors in long-term remission, disease free and off treatment up to January 1st, 1984. The study is introduced by a chapter which describes acute lymphoblastic leukaemia and pays particular attention to the effects of the primary disease on organs which may subsequently exhibit late effects of treatment. Treatment of acute lymphoblastic leukaemia is described in some detail and the reasons for current treatment strategies are outlined. Individual modalities of treatment are then discussed with reference to their mechanisms of action and potential for damage to non-neoplastic tissue. The study then examines all systems likely to have been damaged during therapy, in order to achieve a comprehensive impression of the late effects of leukaemia treatment. In each chapter, pertinent literature was reviewed up to January 1987. Growth is a major task of childhood. Many chronic diseases are potential causes of growth failure. A longitudinal retrospective study showed that statured growth in leukaemia survivors was stunted during treatment. Catch-up growth did not occur at the end of treatment, although normal growth velocity was resumed. Adult height was expected to be reduced as a result. In addition to temporary stunting of statured growth, leukaemia survivors showed a progressive increase in weight-for-height during treatment. This trend continued after treatment had ended. These changes in weight and height were peculiar to leukaemia survivors. Control groups of children with solid tumours in long term remission showed less stunting during treatment and had catch-up growth after treatment, except when they had undergone spinal i rradi ati on. Normal endocrine function is a prerequisite for normal growth and development. Although growth hormone responses to insulin-induced hypoglycaemia were frequently and significantly abnormal in survivors of childhood leukaemia, these children grew normally once treatment had stopped. Impaired growth hormone secretion appeared to be a marker of hypothalamic damage caused by leukaemia therapy. Testicular and ovarian function was normal in the absence of irradiation of these organs. Thyroid function was normal in leukaemia survivors although a minority showed evidence of hypothalamic damage in their response to thyrotropin releasing hormone. Normal prolactin levels in children showing other hormonal evidence of hypothalamic damage were thought to indicate the selectivity of damage caused by leukaemia treatment. Adrenal control and function were normal in leukaemia survivors. In the absence of a growth disorder, only thyroid status may need long-term assessment in leukaemia survivors. Intellectual development is a further major task of childhood. A sibling-controlled study of intellectual function indicated an intelligence deficit in children surviving leukaemia and its treatment. This deficit was thought to be the consequence of therapy, since children surviving solid tumours showed no such deficit in comparison with their sibling controls. Survivors of childhood leukaemia also had an increased incidence of visual perceptual difficulty and more school prob 1 ems than survivors of solid tumours, particularly in early primary grades. Intellectual outcome and school performance in leukaemia survivors may be improved by early visual perceptual training. Children surviving acute lymphoblastic leukaemia had significantly more minor motor abnormalities than children surviving solid tumours. Minor motor abnormalities were frequently and significantly associated with abnormalities of the brain visualized by computerized tomography. Neurophysiologic measurement (EEG, VER, BAER) did not contribute to the assessment of neurological outcome and correlated poorly with clinical and CT scan findings. A functional assessment of neurological outcome in leukaemia survivors should include a clinical examination for minor motor dysfunction. Some children manifested other organ-specific damage due to chemotherapy or radiotherapy. These isolated cases are discussed in the form of case reports and literature reviews. Patients have received treatment with cytotoxic drugs in addition to standard leukaemia therapy need to be followed for treatment-specific late effects. The psychological outcome of leukaemia survivors was assessed by means of parent interviews and teacher questionnaires. In terms of a low frequency of behaviour problems reported by these observers, psychosocial adaptation in leukaemia survivors vas surprisingly good. Children surviving solid tumours and healthy school children from the same community (the latter from a literature report) had similar frequencies of behavioural problems. In both leukemic children ana solid tumour control patients, certain patterns of family behaviour ~ere predictive of a poor psychological outcome. It appears that an early family assessment may identify families 'at risk'. If needs to be shewn whether such families would benefit from professional psychological support. In the final chapter a 'functional deficit score' is offered as a measure of overall outcome in terms of late effects of therapy. Patients were rated in five categories (growth, intellectual outcome, neurological status, miscellaneous organ damage and psychosocial adaptation) according to the severity of persistent late effects. Children surviving acute lymphoblastic leukaemia were shown to have been more seriously damaged by their treatment than children surviving solid tumours. The difference in overall damage was the consequence of central nervous system injury. Available evidence indicates that this central nervous system injury is caused by radiotherapy (with or ·thought a synergistic effect with i intrathecal 1 methotrexate) given as central nervous system 'prophylaxis'. With few exceptions, leukaemia survivors in this study had received L400 rads of deep x-ray therapy as cranial irradiation. This dosage has since been reduced world-wide. Current cranial irradiation 'prophylaxis' consists of 1800 rad of megavoltage radiotherapy. Fa 11 ow-up studies of survivor cohorts given such radiotherapy should include the measures embodied in the 'functional deficit score' described above.

Thesis (Ph.D.)--Murdoch University, 2003. / Thesis submitted to the Division of Health Sciences. Bibliography: leaves 177-201.

Thesis (Ph. D.)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (leaves 323-367). Also available via the World Wide Web.

Thesis (M.S.)--Ball State University, 2008. / Title from PDF t.p. (viewed on Sept. 09, 2009). Includes bibliographical references (p. [93]-101).

Tal-1 is a transcription factor that is frequently ectopically expressed in the majority of cases of T-cell acute lymphoblastic leukemia (T-ALL). The ectopic expression of Tal-1 in patients with ALL has been found to decrease susceptibility to chemotherapeutic drugs and apoptosis. Thus, this study focuses on the effects of endogenously expressed Tal-1 in the Jurkat cell line on three Bcl-2 family members (Bcl-2, Bcl-xL, and Bid) and the inhibition of apoptosis and cell viability when exposed to apoptosis inducing drugs such as etoposide. The data obtained indicate that when treated with etoposide for 12 h Jurkat cells endogenously expressing Tal-1 have an 81% higher level of anti-apoptotic Bcl-2 expression, an 18% lower level of anti-apoptotic Bcl-xL, expression, and a 31% lower level of pro-apoptotic Bid expression compared to Jurkat cells lacking Tal-1 expression. The data also demonstrates that Jurkat cells endogenously expressing Tal-1 have a 15.94% lower amount of cell death after treatment with etoposide for 12 h and a 20.34% lower amount of cell death after treatment with etoposide for 24 h when compared to Jurkat cells that lack Tal-1 expression. Thus, the endogenous expression of Tal-1 increases the amount of the anti-apoptotic Bcl-2 expression and decreases the amount of the pro-apoptotic Bid creating an overall anti-apoptotic signal within the cell. / Department of Biology

Childhood acute lymphoblastic leukemia (ALL) is the most common malignancy in children. Several proto-oncogenes that encode nuclear proteins are activated by various chromosomal translocations in ALL including TALI, TAL2, and LMO1 and LMO2. Ectopic TALI expression is observed in about 50 % of T-ALL and is the most common genetic anomaly associated with this pathology. Of interest to the present work is the characterization of various multiprotein complexes and protein protein interactions that drive T-ALL progression (as it relates to TALI and LMO1) and over expression of TALI and LMO1 has been shown to have inhibitory effects on apoptosis. Recent data suggests possible interactions between these two oncoproteins and the protein product of the lipoprotein lipase (LPL) gene. Lipoprotein lipase has a complex pattern of regulation and can be regulated in different ways including down-regulation upon induction of TNF-a in 3T3-L1 cells. Thus, this study was undertaken to determine if LPL is expressed in cells over expressing TAL1 and LMO1. Results from this study demonstrated an increase in LPL expression at both transcriptional and translational level in cells engineered to express TAL1 alone and TAL1 and LMO1 together. This finding is a step forward to understanding mechanisms that result in apoptosis prevention in T-ALL. Therefore, the apoptosis preventive role seen in cells that over express TAL and LMO1 and the presence of LPL in the same cell line, theorizes an apoptosis preventive role for lipoprotein lipase as well. / Department of Physiology and Health Science

Thesis (Ph.D.)--University of Western Australia, 2007.

Thesis (M.S.)--University of British Columbia, 2005. / Includes bibliographical references (leaves 33-41). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (M. Sc.)--University of British Columbia, 2005. / Includes bibliographical references (leaves 33-41).