Fig. 5

DB-1310 suppresses EGFRm NSCLC tumor growth. (a) Surface HER3 expression on NCI-H1975 NSCLC cells was measured by FACS after osimertinib stimulation for 24 h. (b) NCI-H1975 cells were treated with vehicle or 25 nM osimertinib for 24 h. HER3 internalization was measured by treatment with pHrodo-labeled DB-1310. (c) NCI-H1975 cells were treated with 25 nM osimertinib with or without DB-1310 at 200nM or 1000nM for 5 days. Cell viability was measured by a CTG assay. (d) NCI-H1975 tumor cells were inoculated into BALB/c nude mice, and the mice were treated with DB-1310 (i.v. one treatment) and/or osimertinib (p.o. daily). Tumor growth and body weight were measured. (e) An osimertinib resistant PDX model (LD1-0025-200717) was established with samples from osimertinib-refractory NSCLC patients, and the mice were treated with DB-1310.