Targeting Drug Resistance in Chronic Myeloid Leukemia: A Dissertation
Authors
Ma, LeyuanFaculty Advisor
Michael R. Green, M.D., Ph.D.Academic Program
Interdisciplinary Graduate ProgramUMass Chan Affiliations
Molecular, Cell, and Cancer Biology DepartmentDocument Type
Doctoral DissertationPublication Date
2016-11-08Keywords
Dissertations, UMMSLeukemia, Myelogenous, Chronic, BCR-ABL Positive
Antineoplastic Agents
Drug Resistance, Neoplasm
Leukemia
Myelogenous
Chronic
BCR-ABL Positive
Antineoplastic Agents
Drug Resistance
Neoplasm
Chronic Myeloid Leukemia
Cellular and Molecular Physiology
Hemic and Lymphatic Diseases
Medicinal Chemistry and Pharmaceutics
Neoplasms
Oncology
Pharmacology
Therapeutics
Metadata
Show full item recordAbstract
Inhibiting BCR-ABL kinase activity with tyrosine kinase inhibitors (TKIs) has been the frontline therapy for CML. Resistance to TKIs frequently occurs, but the mechanisms remain elusive. First, to uncover survival pathways involved in TKI resistance in CML, I conducted a genome-wide RNAi screen in human CML cells to identify genes governing cellular sensitivity to the first generation TKI called IM (Gleevec). I identified genes converging on and activating the MEK/ERK pathway through transcriptional up-regulation of PRKCH. Combining IM with a MEK inhibitor synergistically kills TKI-resistant CML cells and CML stem cells. Next, I performed single cell RNA-seq to compare expression profiles of CML stem cells and hematopoietic stem cells isolated from the same patient. Among the genes that are preferentially expressed in CML stem cells is PIM2, which encodes a pro-survival serine-threonine kinase that phosphorylates and inhibits the pro-apoptotic protein BAD. Inhibiting PIM2 function sensitizes CML stem cells to IM-induced apoptosis and prevents disease relapse in a CML mouse model. Last, I devised a CRISPR-Cas9 based strategy to perform insertional mutagenesis at a defined genomic location in murine hematopoietic Ba/F3 cells. As proof of principle, we showed its capability to perform unbiased, saturated point mutagenesis in a 9 amino acid region of BCR-ABL encompassing the socalled “gatekeeper” residue, an important determinant of TKI binding. We found that the ranking order of mutations from the screen correlated well with their prevalence in IM-resistant CML patients. Overall, my findings reveal novel resistance mechanisms in CML and provide alternative therapeutic strategies.DOI
10.13028/M2HS3VPermanent Link to this Item
http://hdl.handle.net/20.500.14038/32246Rights
Copyright is held by the author, with all rights reserved.ae974a485f413a2113503eed53cd6c53
10.13028/M2HS3V