Galunisertib (LY2157299) is a TGF-β receptor type I (TGF-βRI) inhibitor (IC50=56 nM) that is selective. Galunisertib has antitumor activity and can be used in combination with PD-1 inhibitors.

TβRI:56 nM (cell free), TGFβRII:210 nM, 4T1 cells:> 0.1 μM, HaCaT cells:> 0.1 μM

Briefly, the assay was first done at 30°C for 4 h in a 96-well plate containing 2 ng/mL TGF-bR KD, 100 mM Hepes pH 7.5, 4 mM MgCl2, 0.2 mM MnCl2, 0.4 mM sodium orthovanadate, 2 mM DL-dithiothreitol, and 10mM ATP. After incubation, 50mL of Kinase-Glo plus reagent was added and further incubated at 25°C for 30 min. Subsequently, a 100mL aliquot of each reaction mixture was transferred to a black mictotiter plate and the luminescence was measured by a vector counter. The inhibitory activity IC50 was tested in duplicate for each sample [1].

Cell survival was determined using the MTT assay. The conversion of yellow water-soluble tetrazolium MTT into purple insoluble formazan is catalyzed by mitochondrial dehydrogenases and used to estimate the number of viable cells. In brief, cells were seeded in 96-well tissue culture plates at a density of 2 × 103 cells/well. After drug exposure, cells were incubated with 0.4 mg/mL MTT for 4 hours at 37°C. After incubation, the supernatant was discarded, insoluble formazan precipitates were dissolved in 0.1 mL of DMSO, and the absorbance was measured at 560 nm by use of a microplate reader. Wells with untreated cells or with drug-containing medium without cells were used as positive and negative controls respectively. For proliferation assay, MTT assay was done daily to determine the number of viable cells in untreated control and galunisertib-treated group [2].

Transgenic mice expressing a fusion gene (Alb/TGF) consisting of modified porcine TGF-β1 cDNA under the control of the regulatory elements of the mouse albumin gene (26) were used under animal institute approved protocol. Mice were given LY-2157299 at a dose of 100mg/kg/day in NaCMC/SLS/PVP/antifoam solution by gastric lavage using a curved 14 G needle. Blood counts were analyzed by the Advia machine. Mice femurs were flushed and bone marrows cells were used for clonogenic assays [3].