The CRISPR/Cas9 system efficiently reverts the tumorigenic ability of <i>BCR/ABL in vitro</i> and in a xenograft model of chronic myeloid leukemia

Abstract

// Ignacio Garc&iacute;a-Tu&ntilde;&oacute;n 1, * , Mar&iacute;a Hern&aacute;ndez-S&aacute;nchez 1, * , Jos&eacute; Luis Ordo&ntilde;ez 1 , Veronica Alonso-P&eacute;rez 1 , Miguel &Aacute;lamo-Quijada 1 , Rocio Benito 1 , Carmen Guerrero 2, 5, 6 , Jes&uacute;s Mar&iacute;a Hern&aacute;ndez-Rivas 1, 2, 3, # , Manuel S&aacute;nchez-Mart&iacute;n 2, 4, 6, # 1 Unidad de Diagn&oacute;stico Molecular y Celular del C&aacute;ncer, Centro de Investigaci&oacute;n del C&aacute;ncer-IBMCC (USAL-CSIC), Salamanca, Spain 2 IBSAL, Instituto de Investigaci&oacute;n Biom&eacute;dica de Salamanca, Salamanca, Spain 3 Servicio de Hematolog&iacute;a, Hospital Universitario de Salamanca, Salamanca, Spain 4 Servicio de Transg&eacute;nesis, Nucleus, Universidad de Salamanca, Salamanca, Spain 5 Instituto Biolog&iacute;a Molecular y Celular del C&aacute;ncer (USAL/CSIC), Salamanca, Spain 6 Departamento de Medicina, Universidad de Salamanca, Salamanca, Spain * Co-first authors, these authors contributed equally to the work # These authors have contributed equally and share senior authorship Correspondence to: Manuel S&aacute;nchez-Mart&iacute;n, email: adolsan@usal.es Jes&uacute;s Mar&iacute;a Hern&aacute;ndez-Rivas, email: jmhr@usal.es Keywords: CRISPR/Cas9, genome edition, BCR/ABL, leukemia Received: December 28, 2016&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Accepted: January 27, 2017&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Published: February 09, 2017 ABSTRACT CRISPR/Cas9 technology was used to abrogate p210 oncoprotein expression in the Boff-p210 cell line, a pro-B line derived from interlukin-3-dependent Baf/3, that shows IL-3-independence arising from the constitutive expression of BCR-ABL p210. Using this approach, pools of Boff-p210-edited cells and single edited cell-derived clones were obtained and functionally studied in vitro . The loss of p210 expression in Boff-p210 cells resulted in the loss of ability to grow in the absence of IL-3, as the Baf/3 parental line, showing significantly increased apoptosis levels. Notably, in a single edited cell-derived clone carrying a frame-shift mutation that prevents p210 oncoprotein expression, the effects were even more drastic, resulting in cell death. These edited cells were injected subcutaneously in immunosuppressed mice and tumor growth was followed for three weeks. BCR/ABL -edited cells developed smaller tumors than those originating from unedited Boff-p210 parental cells. Interestingly, the single edited cell-derived clone was unable to develop tumors, similar to what is observed with the parental Baf/3 cell line. CRISPR/Cas9 genomic editing technology allows the ablation of the BCR/ABL fusion gene, causing an absence of oncoprotein expression, and blocking its tumorigenic effects in vitro and in the in vivo xenograft model of CML. The future application of this approach in in vivo models of CML will allow us to more accurately assess the value of CRISPR/Cas9 technology as a new therapeutic tool that overcomes resistance to the usual treatments for CML patients.