Figure 5: SOS1 N233Y mutant OCIAML5 cells are dependent on SOS1 for growth, and are sensitive to the MEK inhibitor trametinib.
A: SOS1 dependency scores from shRNA knockdown in AML cell lines were ranked (data from (33)). Cell lines with scores <=−2 are considered dependent on SOS1. OCI-AML5 has a SOS1 N233Y mutation and is labeled in red. OCI-AML3 has an NRAS Q61L mutation and is third from top.
B: SOS1 knockdown using shRNAs. Three different shRNAs targeting SOS1 were used, with at least three biological replicates performed for each shRNA. Cell viability is normalized to shGFP control.
C: Western blot of SOS1, p-MEK, and MEK, with vinculin control, in parental and SOS1-knockdown OCI-AML3 (NRAS mutant) and OCI-AML5 (SOS1 mutant) cells.
D: OCI-AML3, OCI-AML5, and PC-9 (EGFR mutant) cells were tested for their sensitivity to erlotinib (10−4 to 10 μM) and trametinib (10−6 to 10 μM). Cell viability is normalized to DMSO-treated cells. Error bars represent SEM from at least three biological replicates, with six technical replicates each.
E: NIH-3T3 cells expressing the SOS1 N233Y mutant were grown in soft agar under different concentrations of trametinib and imaged after 3 weeks at 6.3×, with cells expressing KRAS G12V as a control. Colonies were quantified using Cell Profiler and normalized to DMSO-treated colonies. Error bars represent SEM.