In vivo CRISPR/Cas9 targeting of fusion oncogenes for selective elimination of cancer cells

Abstract

Fusion oncogenes (FOs) are common in many cancer types and are powerful drivers of tumor development. Because their expression is exclusive to cancer cells and their elimination induces cell apoptosis in FO-driven cancers, FOs are attractive therapeutic targets. However, specifically targeting the resulting chimeric products is challenging. Based on CRISPR/Cas9 technology, here we devise a simple, efficient and non-patient-specific gene-editing strategy through targeting of two introns of the genes involved in the rearrangement, allowing for robust disruption of the FO specifically in cancer cells. As a proof-of-concept of its potential, we demonstrate the efficacy of intron-based targeting of transcription factors or tyrosine kinase FOs in reducing tumor burden/mortality in in vivo models. The FO targeting approach presented here might open new horizons for the selective elimination of cancer cells.

HDAC6 regulates expression of the oncogenic driver EWSR1-FLI1 through theEWSR1promoter in Ewing sarcoma

“…Even though HDAC6 activity has been described mainly in the cytoplasm (Lee et al, 2008;Seidel et al, 2015), there is increasing evidence about its nuclear location (Li et al, 2008;Mobley et al, 2017;Wang et al, 2009;Yang et al, 2015). Here, we demonstrated the nuclear presence of HDAC6 in EWS cell lines by cell fractionation.…”

“…Due to the intrinsic characteristics of EWS, restoring epigenetic changes and inhibiting the oncogenic fusion protein could be a promising therapeutic alternative for EWS patients (Gierisch et al, 2019;Herrero-Martin et al, 2009;Kovar et al, 2016;Martinez-Lage et al, 2020;Nacev et al, 2020;Scotlandi et al, 2020;Van Mater & Wagner, 2019). EWSR1-FLI1 enhances HDAC activity and inhibits HATs, thereby reducing histone acetylation levels (Sakimura et al, 2005).…”

“…This reciprocal translocation generates a fusion oncogene, with EWSR1-FLI1 being the most common (Delattre et al, 1992;Grunewald et al, 2018). Continuous expression of EWSR1-FLI1 in a permissive cellular context is essential both for preserving the malignant phenotype in EWS cells and for their survival, and its inhibition induces apoptosis (Gierisch et al, 2019;Herrero-Martin et al, 2009;Kinsey et al, 2006;Martinez-Lage et al, 2020;Prieur et al, 2004;Smith et al, 2006). As EWS tumors have a remarkably stable genome at time of diagnosis (Crompton et al, 2014), the role of EWSR1-FLI1 in the EWS epigenome regulation has been deeply explored.…”

Future Approaches for Treating Chronic Myeloid Leukemia: CRISPR Therapy

“…In the last five years, the number of scientific papers reporting work on CRISPR/Cas9 in the context of leukemia research has increased enormously [67][68][69][70][71]. Many of them concern in vitro studies to clarify the role of a variety of genes in leukemia development [72].…”

“…A new approach based on the use of two guides to induce a large deletion and selectively eliminate fusion oncogenes has been developed by Rodriguez-Perales and coworkers [69]. This new strategy induces a large genomic deletion in the tumor cells and shows great inhibition-specific tumor growth in a K562 xenograft model.…”