Figure 1. A Genome-wide Gain-of-Function Screen Identifies Candidate Mediators of Resistance to FGFR Inhibition.

A) Schematic overview of the experimental approach. NCI-H2077 cells were transduced with a genome-wide Open Reading Frame (ORF) pooled barcoded library derived from the CCSB-Broad Lentiviral Expression Library. ORF-expressing cells were selected for, and then treated with BGJ398, FIIN-3 or DMSO as indicated. After 14 days of drug exposure, cells were harvested to assess for enriched ORFs compared to the early-time point (ETP) sample.

B) Scatter plot displaying log2-fold-change (LFC) compared to the ETP sample for BGJ398 (first panel) and FIIN-3 (second panel) at concentrations of 100 nM versus 300 nM for each ORF. Replicates were averaged to obtain the LFC for each condition. ORFs associated with LFC greater than or equal to 1.5 (dashed line) at both drug doses were considered mediators of resistance. Several of the top representative candidates are indicated.

C) Venn diagram outlining candidate resistance genes for BGJ398, FIIN-3 or for both drugs. The number of candidate genes for each group is displayed in parenthesis. Genes are organized into functional groups. (GPCR=G-protein-coupled receptor)

D) Summary of primary screening and validation studies.

E) Representative cell viability assay for HRAS wild type ORF validated for BGJ398 (top panel) and FIIN-3 (bottom panel) in NCI-H2077 cells. KRAS G13D and eGFP were used as positive and negative control, respectively.

F) Heat map displaying normalized IC50 (Z-score) for the validation of candidate drivers of resistance to BGJ398 and FIIN-3 in NCI-H2077 cells. Positive control KRAS G13D is displayed in red and negative controls in blue. Experimental ORFs are displayed in orange and ligands in black.

G) Heat map displaying normalized IC50 (Z-score) for a subset of candidate resistance genes in NCI-H2077, RT112, AN3 CA, NCI-H520 and DMS-114 cells for BGJ398 (top heat map) and FIIN-3 (bottom heat map).