Regulatory pathways driving Ph+ Acute Lymphoblastic Leukemia

• Applicant: Dr. Kira Behrens
• Subject Area: Hematology, Oncology ; Cell Biology
• Term: from 2017 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 341020624

Acute lymphoblastic leukemia (ALL) is a form of blood cancer characterized by the overproduction and accumulation of immature white blood cells, known as lymphoblasts. It represents the most common form of paediatric cancer, but also affects adults, in particular elderly people where it is associated with a very poor prognosis. One of the most common genetic aberrations in ALL is the so called Philadelphia chromosome (Ph), a chromosomal translocation t(9;22)(q34;q11) that juxtaposes the Break-point Cluster Region (BCR) and the gene encoding the ABL1 tyrosine kinase resulting in the chimeric BCR-ABL1 protein with constitutive ABL1 activity This in turn leads to the activation of downstream signaling pathways and finally to the uncontrolled cell division of immature B-cell precursors. Although the use of tyrosine kinase inhibitors (TKI) in combination with standard chemotherapy has improved outcomes for Ph+ ALL patients, the relapse rates remain high for patients with minimal residual disease. Therefore, new treatment strategies are required to significantly improve patient prognosis. The aim of this fellowship application is apply innovative genome-wide high-throughput screens to identify key regulators and regulatory pathways driving Ph+ ALL development and progression to enable targeted drug development. Our own preliminary data demonstrating that loss of only a single allele of the transcription factor Erg is sufficient to prevent Ph+ B-ALL development. Here I propose to exploit these findings to perform a) in vitro studies appling a cDNA-expression-library and a CRISPR-Cas9-knockout-library and b) an in vivo Sleeping Beauty transposon mutagenesis screen on wildtype Erg and Erg haploinsufficient Ph+ transgenic mice to screen for factors that can overcome Erg haploinsufficiency-induced failure of leukemia development in murine Ph+ cells. Next generation sequencing will be applied in all three screening approaches to identify deregulated genes. Potential drivers of ALL identified via these screening approaches will initially be confirmed in vitro. Finally, I will conduct xenotransplantation studies of human Ph+ ALL cells engineered to overexpress or down-regulate target gene expression to confirm the relevance of these factors in human leukemia. Together these sophisticated biological, molecular genetic and genomics approaches will provide important insights into the pathology of Ph+ ALL and will help to identify key drivers of the disease, essential for future development of novel targeted therapeutics for the benefit of patients with this poor prognosis leukemia.

• DFG Programme: Research Fellowships
• International Connection: Australia
• Host: Professor Dr. Warren S. Alexander