Cervical cancer is the third most common cancer among women worldwide, and the fourth leading cause of cancer mortality. Despite significant declines in the incidence and mortality rates of cervical cancer in Canada, it remains the 4th most common cancer in women aged 20-29 years. In order to gain novel insights into cervical cancer tumourigenesis and clinical outcome, we investigated and characterized the alterations in microRNA (miRNA) expression in this disease. Firstly, we performed global miRNA expression profiling of cervical cancer cell lines (n=3), and patient specimens (n=79). From this analysis, we identified miR-196b to be significantly down-regulated in cervical cancer, and characterized its role in regulating the HOXB7~VEGF axis. The global miRNA expression data also led to the development of a candidate 9-miRNA signature that was prognostic for disease-free survival in patients with cervical cancer, although we were unable to validate this signature in an independent cohort. This report describes important considerations concerning the development and validation of microRNA signatures for cervical cancer. Our investigations also led us to a comparison of three methods for measuring miRNA abundance: the TaqMan Low Density Array, the NanoString nCounter assay, and single-well quantitative real-time PCR. Our findings demonstrated limited concordance between the TLDA and NanoString platforms, although each platform correlated well with PCR, which is considered the gold standard for nucleic acid quantification. Furthermore, we examined biases created by amplification protocols for microarray studies. Our analysis demonstrated that performing a correction using the LTR-method (linear transformation of replicates) could help mitigate, but not completely eliminate such biases. Overall, this report presents insights into the role of miRNAs in cervical cancer, as well as an evaluation of technical considerations concerning miRNA and mRNA expression profiling studies.

Cervical cancer is the third most common cancer among women worldwide, and the fourth leading cause of cancer mortality. Despite significant declines in the incidence and mortality rates of cervical cancer in Canada, it remains the 4th most common cancer in women aged 20-29 years. In order to gain novel insights into cervical cancer tumourigenesis and clinical outcome, we investigated and characterized the alterations in microRNA (miRNA) expression in this disease. Firstly, we performed global miRNA expression profiling of cervical cancer cell lines (n=3), and patient specimens (n=79). From this analysis, we identified miR-196b to be significantly down-regulated in cervical cancer, and characterized its role in regulating the HOXB7~VEGF axis. The global miRNA expression data also led to the development of a candidate 9-miRNA signature that was prognostic for disease-free survival in patients with cervical cancer, although we were unable to validate this signature in an independent cohort. This report describes important considerations concerning the development and validation of microRNA signatures for cervical cancer. Our investigations also led us to a comparison of three methods for measuring miRNA abundance: the TaqMan Low Density Array, the NanoString nCounter assay, and single-well quantitative real-time PCR. Our findings demonstrated limited concordance between the TLDA and NanoString platforms, although each platform correlated well with PCR, which is considered the gold standard for nucleic acid quantification. Furthermore, we examined biases created by amplification protocols for microarray studies. Our analysis demonstrated that performing a correction using the LTR-method (linear transformation of replicates) could help mitigate, but not completely eliminate such biases. Overall, this report presents insights into the role of miRNAs in cervical cancer, as well as an evaluation of technical considerations concerning miRNA and mRNA expression profiling studies.

Les leucémies aiguës myéloïdes (LAM) sont des proliférations malignes de progéniteurs bloqués lors de la différenciation myéloïde. Le caryotype des blastes leucémiques identifie 3 groupes pronostiques distincts. Parmi les LAM à risque cytogénétique favorable, figurent les leucémies aiguës promyélocytaires (LAP), et celles avec inv(16) ou t(8;21). Les micro-ARNs sont des acteurs clef de l’hématopoïèse et sont aussi impliqués dans la leucémogénèse des LAM. Ils sont très stables dans le sérum et sont utilisés comme biomarqueurs dans les cancers. Le but de cette thèse était d’évaluer si une caractérisation pangénomique des micro-ARNs sériques permettait de distinguer ces 3 types de LAM entre elles ainsi que les LAM avec caryotype normal (NK-AML); d’identifier des micro-ARNs circulants fortement surexprimés dans les NK-AML par rapport à des sujets sains, pour une utilisation ultérieure comme marqueurs de maladie résiduelle; et de mieux préciser le pronostic des NK-AML. Ainsi, nous avons identifié une signature sérique spécifique des LAP liée à une dérégulation des micro-ARNs localisés dans la région DLK1-DIO3 soumise à l’empreinte, en 14q32. Ces micro-ARNs, dont l’origine était le blaste leucémique, étaient corrélés aux facteurs pronostiques connus des LAP. Par ailleurs, deux micro-ARNs, miR-10a-3p et miR-196b-5p, distinguant les NK-AML des LAM avec inv(16) ou t(8 ;21) ont été montré surexprimés dans les NK-LAM avec une mutation de NPM1 et/ou de FLT3-ITD. Enfin l’expression de ces deux micro-ARNs est corrélée à la dérégulation transcriptionnelle et à la méthylation de l’ADN affectant les gènes HOX et TALE. En conclusion, cette étude des micro-ARNs sériques ouvre un nouveau champ d’exploration à visée pronostique dans les LAM. / Acute myeloid leukaemia (AML) is a malignant proliferation of progenitors blocked during myeloid differentiation. The karyotype of the leukemic blasts identified three distinct prognostic groups. Among the favourable risk cytogenetics AML include acute promyelocytic leukaemia (APL), and those with inv (16) or t (8; 21). Micro-RNAs are key players in hematopoiesis and are also involved in leukemogenesis of AML. They are very stable in serum and used as biomarkers in cancers. The aim of this thesis was to evaluate whether a genome-wide characterization of serum micro-RNAs possible to distinguish these three types of AML them as well as AML with normal karyotype (NK-AML); identify micro-RNAs circulating highly overexpressed in NK-AML compared to healthy subjects, for later use as markers of residual disease; and to better define the prognosis of NK-AML. Thus, we have identified a specific serum signing of LAP related to a deregulation of micro-RNAs located in the DLK1-DIO3 under the imprinting, in 14q32. These micro-RNAs whose origin was the leukemic blasts were correlated with known prognosis factors of APL. In addition, two micro-RNAs, miR-10a-3p and miR-196b-5p, distinguishing the NK-AML with inv (16)-AML or t (8; 21)-AML have been shown overexpressed in NK-AML with mutation NPM1 and / or FLT3-ITD. Finally the expression of these two micro-RNAs correlates withtranscriptional deregulation and DNA methylation affectingTALE and HOX genes. In conclusion, this study of serum microRNAs opens a new field of exploration to assess the prognosis in AML.