Ex vivo Evaluation of IACS-010759 in PDX

Ex vivo evaluation of cell viability in response to IACS-010759 exposure was performed in HBCx-137 derived cell cultures, following a protocol detailed elsewhere^{62 (link)}. Briefly, fresh breast cancer PDX tissues were minced and further dissociated using a digestion medium. This was followed by further dissociation using trypsin (GIBCO), Dispase (StemCell Technologies, 7913) and DNase (Sigma, D4513). Cells were resuspended in MEGM (Lonza, CC-3150) and falcon® 40-μm cell strainers were used to remove the undigested tissue. Single-cell suspensions generated from tumours were plated in triplicates at 40,000 cells/well into 96-well plates. The effect of IACS treatment (0 to 15 µM—48 h), with and without Buthionine sulphoximine (BSO) (Sigma, B2515) at 10 mM, on cell viability was determined by CellTiterGlo assay (Promega, G7571) and drug responses represented by the half-maximal inhibitory concentration (IC50) and the dose-response curve. The experiment was performed in two biological replicates. Cell viability was normalised to DMSO (vehicle) treated cells.