CRISPR Screens Identify Essential Cell Growth Mediators in BRAF-inhibitor Resistant Melanoma

Abstract

<jats:title>Abstract</jats:title><jats:p>BRAF is a serine-threonine kinase that harbors activating mutations in ∼7% of human malignancies and ∼60% of melanomas. Despite initial clinical responses to BRAF inhibitors (BRAFi), patients frequently develop drug resistance. To identify candidate therapeutic targets for BRAFi-resistant melanoma, we conducted CRISPR screens in melanoma cells harboring an activating BRAF mutation that had also acquired resistance to BRAFi. The screens identified pathways and genes critical for BRAFi resistance in melanoma cells. To investigate the mechanisms and pathways enabling resistance to BRAFi in melanomas, we integrated expression data, ATAC-seq, and CRISPR screen results. We identified the JUN family of transcription factors and the ETS family transcription factor ETV5 as key regulators of CDK6 that enabled resistance to BRAFi in melanoma cells. Our findings reveal genes whose loss of function conferred resistance to a selective BRAF inhibitor, providing new insight into signaling pathways that contribute to acquired resistance in melanoma.</jats:p>

CRISPR screens reveal genetic determinants of PARP inhibitor sensitivity and resistance in prostate cancer

“…2a, b). The abundance of single guide RNA (sgRNA) for each gene was assessed by β-score and the differential β-score was further calculated using the MAGeCKFlute pipeline by comparing olaparib to DMSO treatment 17,18 . We identified 216, 243, 153, and 211 negatively selected genes (with a stringent cutoff of p-value <0.01), the loss of which sensitizes cells to olaparib in LNCaP, C4-2B, 22Rv1, and DU145 cells, respectively (Fig.…”

“…MAGeCK-VISPR calculated the β-score for each gene by using AAVS1 gene as control. A comparison of the differential β-score between olaparib treatment and DMSO treatment was performed using MAGeCKFlute 17,18 . We ranked genes by differential β-score and robustly estimated σ, which is the standard deviation of the differential β-score by a "quantile matching" approach.…”

The role of the CRISPR‐Cas system in cancer drug development: Mechanisms of action and therapy

“…Recent screening studies on two types of libraries to identify multiple therapeutic agents, such as BRAF inhibitor (vemurafenib), MEK inhibitor (trametinib), ALK inhibitor (crizotinib), EGFR inhibitor (erlotinib), and ATR inhibitor (AZ‐20) have been investigated. [ 33,34 ] These investigations identified new candidate genes linked to drug resistance. For instance, KEAP1 depletion promotes MEK inhibition resistance.…”