shRNA Loss-of-Function Screen Identifies Alternate Pathway for BCR-ABL1 Kinase-independent Resistance in Chronic Myeloid Leukemia

Chronic Myeloid Leukemia (CML) is characterized by increased and unregulated growth of myeloid cells in the bone marrow and accumulation of these cells in the blood. Most CML is caused by a chromosomal abnormality that results in a fusion between Abl tyrosine kinase and BCR gene on chromosome 2, which results in a constitutively active tyrosine kinase. Most CMLs are treated with tyrosine kinase inhibitors (TKI) such as imatinib. Some forms of CML, however, are resistant to TKI treatment and proceed independent of BCR-Abl1 activity. A recent colloborative study utilizing Cellecta’s unique platform in paired imatinib-resistant and imatininb-sensitive K-562 CML cell lines to identify other genes whose knockdown might play a role in the survival of the imatinib-resistant cells.  This loss–of-function  shRNA library screen identified RAN and XPO1, which are components of the nucleocytoplasmic transport complex.

When these genes were knocked down and the cells were treated with imatinib, the cells were more sensitive to imatinib. The shRNA screen also identified other pathways that are involved in TKI resistance, including ubiquitination and proteasomal protein degradation, chromatin remodeling, apoptosis, DNA repair and cell cycle regulation, apoptosis, and antioxidation. These other pathways have yet to be experimentally validated. This study shows that loss-of-function screens are a useful procedure for finding alternative mechanisms of drug resistance in CML.  More information on use of RNAi screens in uncovering drug resistance mechanism is available in this review by Diehl et al.

The figure below shows the mechanisms of oncogene-kinase-independent resistance to TKI therapy in CML. (From Rassool and Perrotti, Blood, (2015) Vol 125:1686-1688.)

Mechanisms of oncogene kinase-independent resistance to TKI therapy in CML
Mechanisms of oncogene kinase-independent resistance to TKI therapy in CML


Leave a comment

Comments will be approved before showing up.


Also in Cellecta Blog & News

Insertion of 10X Genomics' Capture Sequences Does Not Affect HEAT-Tracr sgRNA Efficacy

Read More
Core Population of Cancer Stem Cells Mediates Therapeutic Resistance in Tumors

Researchers at MD Anderson Cancer Center recently used a Cellecta CloneTracker Barcode Library to label patient-derived xenograft (PDX) cells and establish a stable population of aggressive tumorigenic cells with a specific set of barcodes. With this population of barcoded tumorigenic clones, the investigators...
Read More
DriverMap™ Targeted RNA Sequencing of Blood Finds Gene Signatures Linked to Labor

A recent article demonstrates the unique suitability of the DriverMap Expression Profiling Assay for blood biomarker analysis. In Scientific Reports, Tarca, et al. reported that DriverMap Targeted RNA sequencing identified more potential biomarkers associated with spontaneous labor than either standard Illumina...
Read More