Abstract
Core-binding factor leukemia represents a subtype of AML and encompasses 30% of pediatric and 15% of adult
AMLs. The core-binding factor complex is essential in the regulation of normal hematopoiesis and is composed
of AML1 (also known as RUNX1) and CBFB. Chromosomal alterations involving the core-binding factor
complex are well-known “drivers” of leukemia development and have similar clinical and prognostic
implications. A t(8;21) leads to the fusion oncoprotein AML1-ETO and an inv(16) leads to CBFB-MYH11.
Surprisingly, these mutations alone do not induce AML in animal models, suggesting additional “hits” are
required. Mutations in one of four members of the cohesin complex (SMC1a, SMC3, RAD21, STAG1) are
commonly found in patients with AML and frequently (18-20%) co-occur with AML1-ETO, but never with
CBFB-MYH11. This suggests a selective pressure for the presence or absence of cohesin mutations depending
upon the driver oncogene. By learning more about the genetic makeup of these leukemias and how additional
mutations promote leukemogenesis, we can develop targeted therapies which will reduce both toxicity and the
relapse rate compared to existing treatments. We hypothesize that cohesin mutations synergize with
AML1-ETO during leukemic transformation, whereas cohesin mutations and CBFB-MYH11
form a synthetic lethal interaction. In Aim 1, in vivo transplant studies will be performed with AML1-
ETO;SMC3+/+ compared to AML1-ETO;SMC3+/- while CBFB-MYH11;SMC3+/+ and CBFB-MYH11; SMC3+/- will
be studied in vitro. In Aim 2, molecular studies will be performed to delve into the mechanisms driving
leukemia. ChIP-sequencing will be performed to identify changes in AML1-ETO genomic occupancy upon
introduction of cohesin haploinsufficiency. ATAC-seq and RNA-seq will be performed to identify changes in
chromatin accessibility and transcriptome of CBFB-MYH11 due to cohesin haploinsufficiency. Our preliminary
studies indicate that the loss of cohesin augments in vitro self-renewal of AML1-ETO transduced cells.
Preliminary ATAC-sequencing demonstrates that several motifs implicated in myeloid development (RUNX1,
GATA2, ERG, PU.1) are enriched in the AML1-ETO;SMC3+/- background. Further, RNA sequencing reveals
upregulation of the MYC, Rb, and E2F oncogenic gene signatures in AML1-ETO;SMC3+/- compared to SMC3+/+.
Training potential abounds for a future physician scientist within this proposal as it involves using clinical
observations to generate a hypothesis, design a research plan and develop clinical correlations based upon the
results of basic science research. Mentoring support will be easily accessible throughout this training, as will be
all necessary equipment and resources needed to complete this project.