La translocation t(1;9)(q24 ;q34), qui engendre la protéine de fusion RCSD1-ABL1, a été identifiés dans des cas de LAL de mauvais pronostic. Les propriétés oncogéniques du partenaire RCSD1, sa structure et son rôle dans l’activité et la signalisation de RCSD1-ABL1 restent inconnus. Nous avons récemment rapporté le cas d’une LAL-B t(1;9)(q24 ;q34) montrant une résistance à un grand nombre d’ITK, mais une sensibilité inattendue au ponatinib, en l’absence de mutation d’ABL1 susceptible d’expliquer ces réponses.Dans le but de caractériser la protéine RCSD1-ABL1, de comprendre ces profils de réponse aux ITK et de rechercher un traitement optimal de ces leucémies, nous avons cloné le produit de fusion à partir des blastes leucémiques de la patiente. Les constructions obtenues ont été transfectées dans le modèle cellulaire BaF3, ce qui nous a permis : 1) de démontrer et 2) de disséquer pour la première fois l’oncogénicité et la signalisation de la protéine de fusion, au moins partiellement distincte de celle de BCR-ABL1 et notamment concernant l’activation de la voie JAK/STAT; 3) de purifier RCSD1-ABL1 et de révéler l’impact inattendu du bras N-terminal RCSD1 sur l’activité catalytique de l’enzyme et sa sensibilité aux ITK ; 4) d’intégrer ces données et de démontrer l’effet potentialisateur d’inhibiteurs de la voie JAK/STAT sur l’activité des ITK dans les cellules transduites par RCSD1-ABL1 mais pas celles exprimant BCR-ABL1. Enfin, le profilage chémo-génomique de prélèvements issus de 3 patients nous a permis de conforter nos résultats, et de proposer des bases précliniques de traitements personnalisés ciblant ces mécanismes. / The t(1;9)(q24;q34) translocation, generating the RCSD1-ABL1 fusion protein, is found in bad prognosis LAL cases. The oncogenic properties of RCSD1-ABL1 are unknown and the structure of the RCSD1 portion as well as its impact on RCSD1-ABL1 activity and signaling is yet to be determined. We recently reported the case of a patient with ALL associated with a RCSD1-ABL1 rearrangement that was resistant or poorly responsive to a large number of TKIs but was sensitive to Ponatinib, with no mutation that could explain this.In order to characterize this fusion protein, understand its response profile to TKI and optimize therapeutic approaches for these patients, we cloned the RCSD1-ABL1 gene from the patient sample and expressed it in the cellular model BaF3. This allowed us to 1) Demonstrate and 2) Study for the first time the oncogenic properties and signaling of the fusion protein, which is partially distinct from that of BCR-ABL1, especially regarding the JAK/STAT pathway; 3) Purify RCSD1-ABL1 and reveal the impact of the RCSD1 N-terminal portion on the enzyme activity and its TKI sensitivity; 4) Integrate this data and demonstrate the potentiating effect of JAT/STAT pathway inhibitors on TIK activity in cells expressing RCSD1-ABL1 but not in cells expressing BCR-ABL1.Finally, the chemo-genomic profiling of samples from three B-ALL t(1;9)(q24 ;q34) allowed us to consolidate our results and to propose preclinical bases for personalized treatments targeting the identified mechanisms.

Obesity is a recognized problem for children treated for acute lymphoblastic leukemia (ALL) and is present in roughly one fourth of children by the end of therapy. Obesity may lead to immediate health threats, such as an increased risk for cancer relapse, or may cause future heath issues such as diabetes, metabolic syndrome, hypertension, additional cancers, depression or cardiovascular disease. The purpose of this study was to determine if weight gain during two individual cycles of therapy (Induction or Delayed Intensification Cycle 1) were predictive of obesity (defined as body mass index ≥ 95th percentile for age and gender) at the end of treatment. This study retrospectively examined height and weight data from 1,017 childhood leukemia patients treated on Children's Oncology Group (COG) protocol number 1961. This study included patients that had fully completed therapy on protocol 1961 and who were between the ages of 2-20 years. Percentiles and z-scores for age and gender specific body mass index (BMI) were calculated using the height and weight measurements obtained at the beginning of each cycle of chemotherapy. Univariate and multivariate logistic regression analyses were performed. BMI z-score at the beginning of therapy and difference in BMI z-score during Induction were significant predictors (p<0.0001) of BMI ≥ 95th percentile at the end of maintenance in both males and females. A one unit increase in the difference of BMI z-score during Induction resulted in a 3.03 odds ratio (OR) for obesity at the end of therapy for males (95% CI, 1.90 to 4.84) and a 4.15 OR for females (95% CI, 2.32 to 7.43). The change in BMI z-score during Delayed Intensification I was not found to be significant in relationship to obesity at the end of therapy. Weight gain during Induction consisted of ≥ 20% increase in weight for 3.9% of the study participants. Weight gain during Induction therapy of childhood ALL treatment may be useful in predicting patients at increased risk for obesity development during therapy. Early identification of these at risk patients can assist with interventions aimed at normalizing weight gain during therapy.

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Progress in understanding cancer progression has been hampered over the years by the different types of mutations present and irregular changes of gene regulation associated with any given cancer. In this work, molecular interactions between TALI, LMO1, and decorin were investigated. Numerous studies have shown that ectopic expression of decorin protein induced growth suppression in neoplastic cells of various histogenic origins. Furthermore, ectopic expression of TAL1 and LMOI oncoproteins has been shown to occur in approximately 50% of the cases of T-cell acute lymphoblastic leukemia (T-ALL). It was of interest then to determine the preventive or interactive role decorin played with the oncogenic activity of TAL I and LMO1. In this investigation, decorin was introduced into a murine T-cell line (AKR-DP-603) through the use of the mammalian expression vector pcDNA3.1 (-). This particular cell line was previously engineered to express TALI and LMO1. Protein expression patterns in all cell populations were analyzed using the Western blot technique and a proteoglycan with a molecular weight of 100 kDa before chondroitinase ABC treatment and a core protein of55 kDa after treatment with chondroitinase ABC was seen. This finding is significant since it implies that the pcDNA3. 1(-) vector containing decorin cDNA was present, and the corresponding decorin peptides were expressed in both cytoplasmic and nuclear extracts. Furthermore, Northern blot analysis was performed on total RNA extracts to determine the transcriptional state of endogenous decorin rRNA, as well as exogenously introduced decorin. Northern blot analysis revealed no decorin-specific mRNA transcripts from the various cell populations. This result did not imply a lack of possible regulatory effect on protein and mRNA levels of TALL and LMOI by decorin. Finally, cell growth assays were performed on all cell populations and cell counts were used to assess the growth pattern of each population after serum withdrawal. The results show possible growth suppressive effects of decorin on TAL1 and LMOI expressing cells. Results obtained from this study shed further light on the molecular interactions influencing T-ALL and may also help in the design of potentially beneficial cancer treatments using decorin. / Department of Biology

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).

M.Med.(Haematology), Faculty of Health Sciences, University of the Witwatersrand, 2008 / This study aimed to identify the relevance of these prognostic features in the modern treatment era in South African children. A retrospective analysis of the presentation clinical and laboratory features and treatment outcomes of all children treated for Precursor B cell ALL at the Johannesburg Hospital was performed. Between January 1997 and May 2007, 100 children were reviewed. Clinical features (age, race and gender) emerged as significant prognostic variables. Laboratory features (white cell count and genetic features) lacked significance. Early morphologic response on day 15 identified a subgroup associated with a favourable outcome. However the presence of > 5% blasts was not significantly predictive of relapse or death at this time point. Minimal residual disease (MRD) detection by modified immunoglobulin gene rearrangement and flow cytometry techniques did not improve the predictive value of the morphological assessment. In a low resource setting, the challenge is to design cost effective MRD detection methods to improve the identification of patients at risk for relapse.

Children treated for acute lymphoblastic leukemia (ALL) are immunodeficient and therefore at an increased risk of infection and cancer recurrence. Natural killer (NK) cells are a subset of lymphocytes that are very efficient at combatting infections and cancer; however, children treated for ALL have impaired NK cell number and function. Exercise has the potential to bolster NK cell number and function, at least in healthy children and adults. Limited evidence suggests exercise may also have beneficial effects on NK cells in children treated for cancer. However, these previous exercise immunology studies in children with cancer have yielded low sample sizes. Therefore, the aim of this study was to assess the: 1a) feasibility, 1b) acceptability and 1c) safety of performing an exercise intervention in children with ALL. The secondary objectives were to assess the 2a) effects of acute exercise on NK cell number, function and receptor expression in children receiving maintenance therapy for ALL compared to healthy children, as well as to 2b) assess how the NK response changes over 4 months of therapy, and to 2c) assess the link between physical activity and NK cell number and function at rest in children receiving maintenance therapy for ALL. Children undergoing maintenance therapy for ALL (n=4) were recruited from McMaster Children’s Hospital, and healthy sex and pubertal-status matched children (n=4) were recruited from the Hamilton community. ALL patients completed a total of 3 exercise visits, occurring monthly after their regularly scheduled chemotherapy session. At each exercise visit, children were asked to complete 30 minutes of continuous biking, followed by 1 hour of rest. Blood samples were drawn at rest prior to exercise (PRE), immediately after exercise (POST) and 1 hour into recovery (REC). Healthy children only completed one exercise visit. During recovery, participants were asked to complete a physical activity enjoyment scale (PACES) questionnaire and a structured interview in order to assess exercise acceptability and to gauge participant feedback on study components, respectively. Participants were outfitted with an accelerometer to track physical activity levels between visits. Feasibility was assessed by tracking recruitment statistics, study completion rates and exercise completion rates. Acceptability of accelerometer wear was assessed by tracking accelerometer wear and log rates. Safety was assessed by tracking adverse events. All parameters were reported using descriptive statistics. We approached 22 patients to participate, and 4 children completed the study (100% completion rate) out of a goal of 15. Primary deterrents to participation were that patients and families did not want to extend time spent at the hospital or had time restrictions and that patients were uncomfortable with blood collection methods. Exercise was feasible (94% exercise completion rate), acceptable (4.2 ± 0.38 out of 5 PACES score), and safe. Accelerometer wear rates (61.9% (range 3.7-100.0%)) and log completion rates (69.0% (25.9-100.0)) were moderate. Exercise transiently increased NK cell number and function in healthy children and some children with ALL. There were no patterns in the change of the NK cell response to acute exercise over time. We were unable to assess the link between physical activity and NK cells due to a paucity of data. This study cautiously suggests that exercise is a feasible, acceptable and safe intervention that may increase NK cell number and function in children treated for ALL. / Thesis / Master of Science in Medical Sciences (MSMS) / Children treated for leukemia have weak immune systems, making them more susceptible to developing infections and cancer recurrence. Natural killer cells are a special immune cell that is very effective at combatting cancer and infections; however, children treated for leukemia have very low amounts of natural killer cells and they do not function well. Exercise is a simple way to boost the immune system in healthy adults and children, by increasing the number and function of natural killer cells. We don’t know what effect exercise has on natural killer cells in children with leukemia. Previous studies looking at the effects of exercise on the immune system of children with cancer have not been able to recruit enough children to participate. Therefore, it is also important to investigate why children with cancer may not want to participate in exercise studies looking at immune function. The main goals of this thesis were to assess how likely we are to recruit enough children being treated for leukemia to participate in a study looking at how exercise changes natural killer cells, if our participants enjoyed being part of this study, and how safe exercise is for children being treated for leukemia. We also wanted to learn about how natural killer cells respond to exercise in children being treated for leukemia. We found that most of the children and families that decided not to participate in our study felt they did not have time, and the second most common reason for not participating was because the children experienced anxiety surrounding blood draws for the study. The children that decided to participate in the study enjoyed the exercise and being in the study. We also found that the exercise was safe. Finally, we saw that exercise was able to increase natural killer cell numbers and function in some, but not all, children treated for leukemia. The results of this study suggest that exercise may be a realistic and safe way to improve immune function in some children with leukemia.