Imatinib

Cardiomyocytes were plated at a density of 100,000 cells per 35 mm dish. The next day, cardiomyocytes were treated with 200 ng/mL murine stem cell factor (SCF) (Peprotech; Rocky Hill, NJ, USA; 250-03) for one hour. For the cell death assay, cardiomyocytes were pre-treated with 0.5 µM Imatinib (R&D Systems; Minneapolis, MN, USA; 5906) for 2 h.

MCF-7^PAPP-A and MCF-7^PAPP-AE483Q cells were generated as previously described (Takabatake et al). MCF-7, MCF-7^PAPP-A, MCF-7^{PAPP-A/DDR2 KO}, and MCF-7^PAPP-AE483Q cells were grown in Dulbecco’s modified Eagle’s medium (DMEM) supplemented with 10% fetal bovine serum and 1% penicillin/streptomycin at 37 °C/5% CO₂. rIGF-1 (Preprotech, #100-11) treatments were done in serum-free media at 10 nM for indicated time points. Imatinib (R&D Systems, #59-061-00) and PQ401 (Enzo Life Sciences ALX-270-459-M005) treatments were performed at indicated concentrations in complete media for 48 h, and untreated samples were treated with vehicle control (DMSO) for 48 h. PAPP-A- and PAPP-A E483Q-conditioned media treatments were performed at 10 ng/mL in complete media for 24 h. Cells treated with conditioned media were seeded on collagen I-coated plates 24 h prior to treatment. Preparation of collagen-coated plates was performed as follows: type I rat tail collagen (Corning, #354236) was diluted at 50 μg/mL in 0.1 nM HCl and incubated on plates at room temperature for 1 h followed by two PBS washes.