La cryoconservation de tissu ovarien peut être proposée, avant traitements hautement gonadotoxiques, à des patientes afin de préserver leur fertilité. L'autogreffe de tissu ovarien est actuellement la seule méthode de réutilisation du tissu ovarien disponible, mais en cas de pathologie néoplasique, elle présente un risque de réintroduction d'éventuelles cellules malignes via le greffon. L'objectif de ce travail a été de développer une méthode pour détecter la maladie résiduelle (MRD) dans le tissu ovarien par cytométrie en flux multicouleurs (CMF) en cas de leucémie aiguë. Une technique de dissociation de cortex ovarien a été mise au point à partir de tissu ovarien de référence provenant de résections percoelioscopiques. Un modèle expérimental de détection de la MRD a été validé et consistait à ajouter des cellules de leucémie aiguë lymphoblastique (LAL) ou myéloïde (LAM) à une suspension de cellules ovariennes isolées de référence. La méthode a ensuite été utilisée pour rechercher la MRD dans le tissu ovarien cryoconservé de 11 patientes atteintes de leucémie aiguë (7 LAL et 4 LAM).Le modèle expérimental a permis de valider une sensibilité de 10"4 et une spécificité élevée tant pour les LAL que pour les LAM. Lorsqu'un marqueur moléculaire était disponible pour la recherche de la MRD, nous avons observé une bonne corrélation entre la CMF et la PCR quantitative. La détection par CMF de la MRD dans le tissu ovarien des patientes leucémiques était positive chez 3 des 11 patientes étudiées.Cette technique est essentielle pour évaluer le risque carcinologique avant de proposer la réutilisation du tissu ovarien cryoconservé par technique d'autogreffe. / Ovarian cryopreservation together with autograft of frozen/thawed ovarian tissue is a real option to preserve and restorefertility in cancer patients. However in cases of leukemia, there is a real concern regarding the presence of metastaticcells in the ovarian tissue, which could lead to the recurrence of the primary disease. The aim was to validate multicolorflow cytometry (MFC) as an original technique for minimal residual disease (MRD) detection in ovarian cortex fromacute leukemia patients.We developed an experimental model which consisted in adding serial dilutions of leukemic cells into isolated ovariancell suspensions obtained from healthy cortex. The modelization was validated for acute lymphoblastic leukemia (ALL)and acute myeloid leukemia (AML). Then the method was applied to MRD detection of leukemic cells in cryopreservedovarian cortex from 11 leukemia patients (7 ALL and 4 AML).This experimental model made it possible to obtain a high specificity and a robust sensitivity of 10~4 for MRD detectionby MFC for both types of acute leukemic cells. When a molecular marker was available, we observed a good correlationbetween CMF and quantitative PCR. Ovarian MRD was positive by MFC in one T-ALL and 2 AML patients.MRD detection in the ovarian cortex is essential to evaluate the risk of cancer reseeding before ovarian tissue autograft.

Acute leukemias (AL) comprise a heterogeneous group of hematologic malignancies, and individual patient responses to treatment can be difficult to predict. Monitoring of minimal residual disease (MRD) is thus very important and holds great potential for improving treatment strategies. Common MRD targets include immunoglobulin heavy chain or T-cell receptor gene rearrangements, recurrent cytogenetic abnormalities and mutations in important hematological genes. Whereas in the majority of adult acute lymphoblastic leukemia patients a suitable MRD target can be identified, in adult acute myeloid leukemia patients well-characterized targets are found in only half of cases. The identification of new specific molecular markers of leukemic blasts for MRD assessment, particularly in AML patients, is therefore highly desirable. Our aim was to develop a flexible strategy for mapping of cytogenetically identified unique clone-specific abnormalities down to the single nucleotide level and, based on the sequence, design a specific real-time PCR assay for MRD assessment in AL patients without any previously described MRD marker. Using a combination of cytogenetic (chromosome banding, chromosome microdissection), molecular cytogenetic (mFISH, mBAND) and molecular biological (next- generation sequencing, long-range...

Hematopoiesis has been for many years seen as a straightforward process based on sequential restriction of cell fate potential leading to production of mature blood cells. In the last decade, however, several works documented an unexpected plasticity of hematopoietic cells with expanded potential of myeloid development from lymphoid progenitors and vice versa. Under physiologic conditions hematopoiesis is tightly controlled and the definite cell fate is denominated by multiple factors that all lead to changes in regulatory networks that include transcription factors, epigenetic changes and post-transcriptional modulations. Any disruption of this strict regulation, caused by mutations or other events, affects the proliferation and lineage fidelity of hematopoietic precursors. This may lead to clonal growth of variable significance or leukemogenesis and may possibly affect the treatment sensitivity of the hematological malignancies. For better understanding of hematopoietic regulation we described gene expression changes during physiological development of lymphoid and myeloid lineages and in leukemic specimens using our own simplified real-time PCR based platform. We investigated expression of 95 genes connected with lymphoid and myeloid differentiation or with leukemogenesis in sorted hematopoietic...

Acute leukemias (AL) comprise a heterogeneous group of hematologic malignancies, and individual patient responses to treatment can be difficult to predict. Monitoring of minimal residual disease (MRD) is thus very important and holds great potential for improving treatment strategies. Common MRD targets include immunoglobulin heavy chain or T-cell receptor gene rearrangements, recurrent cytogenetic abnormalities and mutations in important hematological genes. Whereas in the majority of adult acute lymphoblastic leukemia patients a suitable MRD target can be identified, in adult acute myeloid leukemia patients well-characterized targets are found in only half of cases. The identification of new specific molecular markers of leukemic blasts for MRD assessment, particularly in AML patients, is therefore highly desirable. Our aim was to develop a flexible strategy for mapping of cytogenetically identified unique clone-specific abnormalities down to the single nucleotide level and, based on the sequence, design a specific real-time PCR assay for MRD assessment in AL patients without any previously described MRD marker. Using a combination of cytogenetic (chromosome banding, chromosome microdissection), molecular cytogenetic (mFISH, mBAND) and molecular biological (next- generation sequencing, long-range...

L’analyse des anomalies génomiques récurrentes est importante pour établir le diagnostic, le pronostic et pour orienter la thérapie des leucémies aiguës pédiatriques. L’objectif de notre étude est d’élaborer une stratégie optimale pour détecter les anomalies chromosomiques dans les leucémies aiguës lymphoblastiques (LAL) et myéloïdes (LAM) des enfants. Pour ce faire, nous avons caractérisé au caryotype, avec des panels d’hybridation in situ en fluorescence (FISH), par RT-PCR et par l’index d’ADN 253 leucémies de novo reçues au CHU Sainte-Justine entre 2005 et 2011 (186 LAL-B, 27 LAL-T et 40 LAM). Nous avons réussi à optimiser la détection des anomalies chromosomiques dans les trois types de leucémies, avec des fréquences de 93,5% dans les LAL-B (174/186), 66,7% dans les LAL-T (18/27) et 90% dans les LAM (36/40). Nos résultats suggèrent d’utiliser plusieurs tests génétiques concomitants afin d’optimiser la détection des anomalies génomiques dans les LAL et les LAM de novo pédiatriques. / Analysis of recurrent genomic abnormalities is important for the diagnosis, prognosis and therapeutic choices in paediatric acute leukemia. The aim of our study is to establish a strategy optimizing the detection of cytogenetic abnormalities in childhood acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). To do so, we have characterized childhood AML and ALL cases received in cytogenetic laboratory of CHU Sainte-Justine (Montreal, Canada) between 2005 and 2011. Overall, 253 de novo cases have been analyzed (186 B-ALL, 27 T-ALL and 40 AML) by karyotyping, fluorescence in situ hybridization (FISH) panels, RT-PCR and DNA index. Chromosomal abnormalities detection rates achieved 93,5% in B-ALL (174/186), 66,7% in T-ALL (18/27) and 90% in AML (36/40). Our results suggest the analysis of both molecular and cytogenetic tests to optimize the detection of genomic abnormalities in new cases of childhood AML and ALL.

L’analyse des anomalies génomiques récurrentes est importante pour établir le diagnostic, le pronostic et pour orienter la thérapie des leucémies aiguës pédiatriques. L’objectif de notre étude est d’élaborer une stratégie optimale pour détecter les anomalies chromosomiques dans les leucémies aiguës lymphoblastiques (LAL) et myéloïdes (LAM) des enfants. Pour ce faire, nous avons caractérisé au caryotype, avec des panels d’hybridation in situ en fluorescence (FISH), par RT-PCR et par l’index d’ADN 253 leucémies de novo reçues au CHU Sainte-Justine entre 2005 et 2011 (186 LAL-B, 27 LAL-T et 40 LAM). Nous avons réussi à optimiser la détection des anomalies chromosomiques dans les trois types de leucémies, avec des fréquences de 93,5% dans les LAL-B (174/186), 66,7% dans les LAL-T (18/27) et 90% dans les LAM (36/40). Nos résultats suggèrent d’utiliser plusieurs tests génétiques concomitants afin d’optimiser la détection des anomalies génomiques dans les LAL et les LAM de novo pédiatriques. / Analysis of recurrent genomic abnormalities is important for the diagnosis, prognosis and therapeutic choices in paediatric acute leukemia. The aim of our study is to establish a strategy optimizing the detection of cytogenetic abnormalities in childhood acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). To do so, we have characterized childhood AML and ALL cases received in cytogenetic laboratory of CHU Sainte-Justine (Montreal, Canada) between 2005 and 2011. Overall, 253 de novo cases have been analyzed (186 B-ALL, 27 T-ALL and 40 AML) by karyotyping, fluorescence in situ hybridization (FISH) panels, RT-PCR and DNA index. Chromosomal abnormalities detection rates achieved 93,5% in B-ALL (174/186), 66,7% in T-ALL (18/27) and 90% in AML (36/40). Our results suggest the analysis of both molecular and cytogenetic tests to optimize the detection of genomic abnormalities in new cases of childhood AML and ALL.

Das Gen H-rev107 wurde mit einer subtraktiven cDNS-Bibliothek zwischen H-ras-transformierten und H-ras-resistenten Fibroblasten isoliert. Es wurde als ein Klasse II Tumorsuppressorgen bezeichnet, dessen Expression die H-ras-induzierte maligne Transformation unterdrückt. Weitere Untersuchungen zeigten die Existenz einer Genfamilie mit dem Gen H-rev107-1 auf Chromosom 11q11-12 und H-rev107-2/TIG3/RARRES3 auf 11q23. Die Induzierbarkeit in epithelialen Zellen durch Interferon-gamma (H-rev107-1) und Retinoide (H-rev107-2) legten eine Beteiligung der Expression beider Gene bei der Regulation der Hämatopoese nahe. In der vorliegenden Arbeit wurde mittels RT-PCR in 8/15 Patientenproben (10 AML, 5 ALL) eine Expression von H-rev107-2 gefunden. H-rev107-2 wurde durch IFN-gamma in 14/14 Proben und durch all-trans Retinsäure (ATRA) in 5/15 Proben induziert. In Zelllinien maligner hämatopoetischer Erkrankungen konnte mit RT-PCR und Northern-Blot-Analysen bei CEM eine deutliche, bei Raji und HL-60 eine schwache Expression und bei NB-4, U937, K562 und Jurkat keine Expression von H-rev107-2 nachgewiesen werden. In allen 7 Zelllinien konnte H-rev107-2 durch IFN-gamma induziert werden. Die Induzierbarkeit durch ATRA und IFN-alpha war Zelllinien abhängig. Die stärkste Induktion durch ATRA erfolgte bei der akuten Promyelozytenleukämie-Zelllinie NB-4. Eine Induktionskinetik erbrachte eine H-rev107-2-Expression frühestens nach 4 h Inkubation mit IFN-gamma oder ATRA. Die Inhibition des MAPK-Signalwegs durch den MEK-Inhibitor PD098059 und des Signaltransduktors JAK2 durch AG490 hatte bei den myeloischen Zelllinien weder Einfluss auf die H-rev107-2-Expression noch auf die H-rev107-2-Induktion durch IFN-gamma oder ATRA. Die Expression von H-rev107-1 konnte bei U937, CEM und K562 gezeigt werden, wogegen die RT-PCR-Analysen bei NB-4, HL-60, Raji und Jurkat sowie bei 8 Patientenproben (6 AML, 2 ALL) keine H-rev107-2-Transkripte nachwiesen. Eine schwache Induktion von H-rev107-1 konnte nur bei den Zelllinien NB-4 durch ATRA und IFN-gamma und bei K562 durch IFN-gamma und IFN-alpha erzielt werden. Zusammenfassend legen die Ergebnisse dieser Arbeit eine Beteiligung von H-rev107-2/TIG3/RARRES3 bei der Regulation der Hämatopoese als ein mögliches Interferon- und ATRA-Target nahe. / The H-rev107 gene has been isolated by cDNA subtraction from a cell culture model of H-ras transformed fibroblasts. It was characterized as a class II tumor suppressor gene confering resistance to H-ras induced transformation. Further investigation has demonstrated the presence of a human gene family with H-rev107-1 localized on chromosome 11q11-12 and H-rev107-2/TIG3/RARRES3 on 11q23. Inducibility of the genes in epithelial cells by interferon-gamma (H-rev107-1) and retinoids (H-rev107-2) has suggested that expression of the H-rev107 genes might be relevant in hematopoesis. In the present study RT-PCR analysis revealed an expression of H-rev107-2 in 8/15 samples of leukaemic blasts derived from patients suffering from acute leukaemias (10 AML, 5 ALL). H-rev107-2 was induced upon incubation with IFN-gamma ?in 14/14 samples and with ATRA in 5/15 samples. In cell lines derived from myeloid and lymphoid tumors an expression of H-rev107-2 was found in CEM (strong), Raji and HL-60 (both weak), whereas in NB-4, U937, K562 and Jurkat no H-rev107-2 transcripts were detected by RT-PCR and Northern Blot analysis. In all cell lines H-rev107-2 could be strongly induced by IFN-gamma. Inducibility of H-rev107-2 upon treatment with IFN-alpha or ATRA was dependent on the type of cell line. In contrast to the weak effect seen in the myeloblastic cell line HL-60 a strong induction of H-rev107-2 by ATRA occurred in the acute promyelocytic leukaemia cell line NB-4. Transcripts of H-rev107-2 in NB-4 were detected at the earliest after 4 h incubation with ATRA or IFN-gamma. Inhibition of the MAPK-pathway by the MEK-inhibitor PD089059 or the signal transducer JAK2 by AG490 had neither influence on the H-rev107-2 expression nor on the IFN-gamma- and ATRA-dependent H-rev107-2 induction. H-rev107-1 expression was detectable in U937, CEM and K562, whereas RT-PCR analysis of the other cell lines and of 8 samples of primary leukaemic blasts (6 AML, 2 ALL) revealed no H-rev107-1 expression. An induction of H-rev107-1 occurred exclusively in NB-4 by ATRA and IFN-gamma and in K562 by IFN-gamma and IFN-alpha? to a weak extend. In conclusion, this work revealed a likely involvement of the class II tumor suppressor gene H-rev107-2/TIG3/RARRES3 in the regulation of hematopoesis being a potential IFN and ATRA target.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2005. / Härtill 4 uppsatser. På omsl. felaktigt " ... daunorobicin ..."

Great progress has been achieved in the diagnostics and therapy of childhood acute lymphoblastic leukemia (ALL) during the last few decades and the permanent cure rate for children and adolescents has risen to nearly 90%. The basic principle of ALL treatment is to split patients into several groups receiving treatment of different intensity according to exactly defined prognostic features. This is aimed at reducing both the risk of relapse and toxic complications of treatment. The development of new diagnostic methods, especially in the field of molecular genetics and flow cytometry, allowed further improvements in the risk stratification - the minimal residual disease (MRD) has become a crucial prognostic factor in modern treatment protocols for pediatric ALL as a sensitive marker of both response to therapy and subclinical leukemic involvement of various tissues of the organism. Nevertheless, there is still an intensive search for new markers that would enable even more precise characterization of the leukemic clone, and treatment strategies reflecting the biology of leukemic cells are being optimized. The first part of our study describes the monitoring and prognostic impact of MRD in peripheral blood of children with ALL with emphasis on very early time points of treatment. MRD was examined by the...

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