THE CRISPR/CAS9 SYSTEM ABOLISHES THE TUMORIGENIC ABILITY OF
BCR/ABL AND RESTORING THE NORMAL HAEMATOPOIESIS IN THE BONE
MARROW NICHE OF NOD/SCID MICE
Elena Vuelta1, José-Luis Ordóñez2, Patricia Hernández-Carabias1, Lucía Mendez1, Raquel Saldaña3,
Julián Sevilla4, Elena Sebastian5, Sandra Muntión6, Fermín Sánchez-Guijo6, Jesús María Hernández-
Rivas2, Ignacio García-Tuñon1 and Manuel Sánchez-Martín1
(1)Universidad de Salamanca, Salamanca, Spain
(2)University of Salamanca, IBSAL, IBMCC, CSIC, Cancer Research Center, Department of Hematology,
University Hospital of Salamanca, Salamanca, Spain, SALAMANCA, Spain
(3)Hospital Jerez de la Fra, SAS Area Norte Cadiz, Cadiz, Spain
(4)Servicio de Hematología y Oncología Pediátrica, Fundación de Investigación Biomédica, Hospital
Infantil Universitario Niño Jesús, Madrid, Spain
(5)Hospital Infantil Universitario Niño Jesús, Madrid, Spain
(6)Hospital Universitario Salamanca, Salamanca, Spain
Chronic myelogenous leukaemia (CML) is a hematological neoplasia driven by a reciprocal
translocation t(9;22)(q34;q11) in the haemopoietic stem cell (HSC) compartment, generating
the fusion oncoprotein BCR-ABL1 with a constitutive tyrosine kinase (TK) activity. Although
tyrosine kinase inhibitors (TKIs) have been a real success in the treatment of the disease,
achieving a favourable therapeutic effect, 25% of patients continue to develop resistance.
Therefore, novel therapeutic approaches for CML are still needed. To address this problem,
we propose the use of the CRSPR/Cas9 system as a definitive therapeutic strategy, capable of
eliminating the BCR/ABL fusion oncogene at the genomic level in the leukemic stem cells
(LSCs) from a CML mouse model and from CML patients at diagnostic. With an anti-ABL
approach, which avoids the problem of the variety of BCR-ABL junctions in CML patients, we
have generated a specific null mutation at high efficiency and allowing to detect and track the
edited leukemic cells. Orthotopic transplantation of the edited mouse LSCs into the bone
marrow niche of NOD/SCID mice showed the reversion of the pathological phenotype.
Analysis of blood populations at 2 and 4 months after transplantation showed the
reestablishment of normal hematopoiesis, obtaining similar values to those found in wild type
mice. Interestingly, bone marrow transplantation of edited CD34+ from CML patients into
NOD/SCID niches revealed the repopulation ability of edited stem cells. The presence of our
specific null edition in mature hematopoietic cell populations, analyzed 6 months after
transplantation, corroborated the multipotent ability of edited LSCs. Importantly,
hematopoiesis derived from the edited LSCs resulted in a significant reduction in the myeloid
population - increased in control pathological transplants- and in a significant increase in
lymphoid cells, reaching physiological levels. In our knowledge, this is the first time it has been
shown that edited CML-LSCs can repopulate the bone marrow of a host mouse, leading to
normal hematopoiesis, without clinical symptoms of the disease. These results constitute
proof of principle that correction of LSCs by genomic deletion of BCR/ABL by CRISPR/Cas9,
avoid their tumorigenic capacity and provide a new therapeutic strategy in CML.
SCIENTIFIC PROGRAMME
SESSION I
OPTIMIZING
CYTOREDUCTION
SESSION II
MANAGEMENT OF CML
WITH TKI
SESSION III
MPN RISK
STRATIFICATION
INCLUDING VASCULAR
EVENTS
DEBATE 1
INTERFERON ALPHA
SHOULD BE FRONT LINE
THERAPY IN ALL ET/PV
PATIENTS
ROUNDTABLE 1
INFECTIONS IN
MYELOPROLIFERATIVE
DISORDERS, INCLUDING
CML
ROUNDTABLE 2
PREGNANCY AND
PARENTING
DEBATE 2
ALLOGENEIC STEM CELL
TRANSPLANTATION
SHOULD BE CONSIDERED
THIRD LINE OPTION IN
CHRONIC PHASE CML
SESSION IV
EVOLVING THERAPIES
IN MYELOFIBROSIS
SESSION V
MANAGEMENT OF
ADVANCED AND UNUSUAL
DISEASE (MPN AND CML)
SESSION VI
TREATMENT FREE
REMISSION IN CML
KEYNOTE LECTURE
SELECTED ABSTRACTS
FOR AN ORAL
PRESENTATION
SELECTED ABSTRACTS
FO R A POSTER
PRESENTATION
DISCLOSURES