Acute myeloid leukemia (AML) MLL
To identify new cancer (e.g. leukemia) biomarkers with diagnostic and/or therapeutic potential based on novel human AML model system
|IP Status||Pending patent application|
|Principal Investigator||Brian Wilhelm and Frédéric Barabé (Université Laval)|
Proprietary MLL-AF9 model system
Identification of cancer specific gene expression changes
Candidate genes already identified and validated as potential AML biomarkers and/or novel therapeutic targets
SCIENTIFIC BACKGROUND AND RATIONALE
Almost 60,000 people will develop leukemia each year in North America and over 13,000 will succumb to this disease. While progress has been made for the treatment of most types of leukemia, acute myeloid leukemia (AML) stands out as an exception, with a strikingly poor outcome where less than half of all patients will be cured.
Current standard treatment for AML is chemotherapy, which can have severe side effects and is ineffective in some cases. Research into the genetic causes of AML has identified recurrent genetic changes, such as rearrangements of the Mixed-Lineage Leukemia (MLL) gene, which are present in ~65% of infant/pediatric AML samples, 10% of adult AML and 30% of therapy-related leukemias. Despite this work, a full understanding of the genetic development of the disease is not available which hinders efforts to develop novel targeted treatments.
Next generation sequencing of the tumor transcriptomes (RNA-seq) of pediatric AML patients with MLL translocations provides information regarding mutations and gene expression present in the disease. While informative, the complex genetic heterogeneity of the individual patients greatly confounds the analysis of the genetic determinates of the leukemia.
The Wilhelm and Barabé labs have used a novel proprietary model system to overcome these limitations, such that multiple human leukemias can be generated from individual human CD34+ cord blood (CB) donor samples. This is equivalent to a single patient independently developing multiple leukemias, effectively removing the problems of patient genetic heterogeneity and scarcity. The comparison of data from the model AMLs samples to hundreds of other AML and non-AML samples has clearly revealed 40 candidate genes specifically expressed in MLL-rearranged leukemias.
A qRT-PCR diagnostic test has been developed based on the expression of 7 of the candidate genes to provide the proof of principle for their efficacy for the detection of minimal residual disease (MRD) after treatment. As with an initial RT-PCR based test where bands can be detected in AML samples but not healthy peripheral blood samples after 30 cycles, the qRT-PCR test has already demonstrated that it can reliably identify cryptic MLL translocations missed by standard cytogenetic tests. The novel qRT-PCR is also much faster and cheaper than standard diagnostics (karyotyping). The qRT-PCR based assay has been validated against a panel of 90 patient and 6 healthy donor controls and shows excellent sensitivity.
Custom-made monoclonal antibodies against the first therapeutic target have been generated and are being functionally tested for both target recognition and functional blockade. Antibodies against 4 other targets will be generated by Sept 2016 and subsequently validated in vitro. We have also validated in vitro and in vivo that the first therapeutic target is an essential gene for MLL translocated AMLs.
Functional validation of antibodies against first tumor biomarker using mouse models along with the development and validation of additional antibodies against several (n=4) additional novel candidate genes. These antibodies will be tested in vivo and optimized for clinical use in humans. Key deliverable: Monoclonal antibodies against cell surface molecules with in vivo for anti-tumor activity.
Brian Wilhelm, Ph.D.
- Head of the High-Throughput Genomics research unit, IRIC
- Research Assistant Professor, Dpt of Medicine, Faculty of Medicine, UdeM
After finishing his undergraduate studies in the Co-op Biology program at the University of Waterloo, Brian Wilhelm undertook his Ph.D. in Medical Genetics at the University of British Columbia in the lab of Dr. Dixie Mager where he studied the transcriptional regulation of the Ly49 family of NK receptors.
His interest in studying transcriptional regulation in a more global fashion took him to the functional genomics lab of Dr. Jürg Bähler, then at the Wellcome Trust Sanger Institute (WTSI) in Cambridge, U.K. During this postdoctoral term, Brian Wilhelm was able to gain wide-ranging experience in using microarrays to study gene expression and protein DNA interactions (ChIP-chip). Technology development at the WTSI also provided the opportunity to utilize next-generation DNA sequencing technologies and to use these to study transcriptional behaviour.
After his arrival in Montréal in 2007, Brian conducted additional post-doctoral training in the lab of Dr. Guy Sauvageau at IRIC to study the biology of normal and leukemic hematopoietic stem cells.
Since 2010, Dr. Wilhelm has been an independent principal investigator at IRIC and an assistant professor in the department of Medicine at the University of Montreal. His research focuses on using integrated global approaches to better decipher the genetic basis for pediatric acute myeloid leukemia.
Frédéric Barabé, MD.
- Clinical Hematologist, CHU de Québec- Université Laval
- Associate Professor, Department of Medicine, Faculty of Medicine, Université Laval
Frédéric Barabé got his MD from Université Laval in 1998. He did his residency at Université Laval from 1998 to 2003 and is fellow of the Royal College of Physician of Canada in both internal medicine and hematology. After his residency in hematology, Dr Barabé moved to Toronto where he did his postdoctoral training with Dr John Dick at the University Health Network with a CIHR clinician-scientist award. He worked on both human normal hematopoietic stem cells and leukemic stem cells with extensive work with xenograft models of human hematopoiesis. He studied the transformation of human primary hematopoietic cells into leukemic cells both in vitro and in vivo and developed a model of acute human leukemias in a xenotransplantation model using MLL fusion genes (Barabé et al, Science 2007).
Dr Barabé returned to Quebec City in 2007 as a clinician scientist at CHU de Québec-Université Laval and professor at the Faculty of Medicine. He is an independent investigator since 2007 and runs a research program that focuses on understanding the molecular and cellular mechanisms involved in the transformation of human stem/progenitor cells into leukemic stem cells.