Therapy-related myeloid neoplasms (t-MNs) are late complications of cytotoxic therapy typically for primary malignant diseases. Heterozygous deletions of the long arm of chromosome 5, del(5q), are frequently noted in t-MN following cytotoxic treatment with alkylating agents, and are associated with loss or mutations of TP53. To identify a leukemia-related gene on chromosome 5, we previously delineated a 970 kb commonly deleted segment (CDS) of 5q31.2, and identified the first haploinsufficient myeloid suppressor gene within this CDS, EGR1. We also identified APC as another haploinsufficient myeloid suppressor gene on 5q. We developed an Mx1-Cre+ Apcfl/+-inducible model, and showed that Apc is essential for the maintenance and survival of hematopoietic stem and progenitor cells (HSPCs). Apcdel/+ mice develop a severe macrocytic anemia, recapitulating characteristic features of t-MN with a del(5q). Notably, concordant haploinsufficiency for Egr1 and Apc cooperates to accelerate anemia onset. We showed that cell intrinsic loss of Tp53 in HSPCs haploinsufficient for Egr1 and Apc led to the development of an aggressive AML in mice, representing the first mouse model for human del(5q) AML. We hypothesize that 5q contains one or more additional myeloid suppressor genes (cis mutations) that cooperate with EGR1 and APC haploinsufficiency, and that additional cooperating mutations (trans mutations) are required for leukemogenesis. The overall goal of this project is to identify cooperating mutations and genetic pathways leading to alkylating agent-induced t-MN with a del(5q). Through collaborations, we will compare genetic pathways identified by genomic analysis of t-MN patients and mouse models for the del(5q), as well as mouse models for the haploinsufficient genes involved in the - 7/del(7q) and loss of 17p, commonly seen together with the del(5q) in t-MN.
In Aim 1, we will identify the molecular mechanisms of transformation by EGR1 by characterizing the role of EGR1 in hematopoiesis. Specifically, we will identify the transcriptional targets of EGR1 in HSPCs, and t-MNs with a del(5q), and examine the mechanism by which lesions on 5q and 7q cooperate.
In Aim 2, we will identify genetic mutations that cooperate with haploinsufficiency of EGR1 and/or APC in the pathogenesis of myeloid neoplasms by characterizing the genomic pattern of myeloid neoplasms arising in mice with haploinsufficiency for Egr1, Apc, and Tp53, or ENU-treated Egr1+/- mice (an alkylating agent-induced myeloid neoplasm), and by evaluating the cooperative role of candidate myeloid suppressor genes on 5q, e.g., CSNK1A1, SPRY4, and the lysine specific deaminase, KDM3B. In conducting this work, we will generate genetically accurate and tractable in vivo models for preclinical studies, providing critical resources for investigating the fundamental problem of drug resistance in t-MN. Establishing the genetic pathways leading to t-MN may inform the development of biologically-based treatment strategies.

Public Health Relevance

The identification of myeloid leukemia genes on chromosome 5 represents a high experimental priority due to the high frequency of, and poor prognosis (median survival, 8 mos) associated with, abnormalities of this chromosome. Elucidating the genetic pathways leading to myeloid neoplasms with a del(5q) may provide insights into hematopoiesis and leukemic transformation, and may ultimately lead to the development of rational new therapeutics.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA190372-05
Application #
9614271
Study Section
Cancer Molecular Pathobiology Study Section (CAMP)
Program Officer
Fingerman, Ian M
Project Start
2015-02-01
Project End
2020-01-31
Budget Start
2019-02-01
Budget End
2020-01-31
Support Year
5
Fiscal Year
2019
Total Cost
Indirect Cost
Name
University of Chicago
Department
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
McNerney, Megan E; Godley, Lucy A; Le Beau, Michelle M (2017) Therapy-related myeloid neoplasms: when genetics and environment collide. Nat Rev Cancer 17:513-527
Stoddart, Angela; Wang, Jianghong; Hu, Chunmei et al. (2017) Inhibition of WNT signaling in the bone marrow niche prevents the development of MDS in the Apcdel/+ MDS mouse model. Blood 129:2959-2970
Stoddart, Angela; Qian, Zhijian; Fernald, Anthony A et al. (2016) Retroviral insertional mutagenesis identifies the del(5q) genes, CXXC5, TIFAB and ETF1, as well as the Wnt pathway, as potential targets in del(5q) myeloid neoplasms. Haematologica 101:e232-6
Stoddart, Angela; Nakitandwe, Joy; Chen, Shann-Ching et al. (2015) Haploinsufficient loss of multiple 5q genes may fine-tune Wnt signaling in del(5q) therapy-related myeloid neoplasms. Blood 126:2899-901
Stoddart, Angela; Fernald, Anthony A; Wang, Jianghong et al. (2014) Haploinsufficiency of del(5q) genes, Egr1 and Apc, cooperate with Tp53 loss to induce acute myeloid leukemia in mice. Blood 123:1069-78