Galunisertib (LY2157299) is an orally available inhibitor of TGFβRI kinase (IC50: 56 nM) with potential antineoplastic activity.

The HCC cell lines were simultaneously exposed to 0.1, 1, 10, and 100 μM galunisertib (LY-2157299) with 5 μM sorafenib in presence of TGF-β for 72 hours. Galunisertib displayed a slight dose-dependent potentiation of sorafenib in SK-Sora, HepG2, and Hep3B cell lines but not in JHH6, SK-HEP1, and HuH7 cell lines [2]. Leukemic cells (K562) and marrow stromal cells (HS-5) were treated with TGF-β1 (20 ng/ml) in the presence and absence of LY-2157299 (5 μM) and assessed for SMAD2 phosphorylation by immunoblotting. LY-2157299 pretreatment (1 hr) led to attenuation of activation/phosphorylation of SMAD2 [3].

Mice transgenic for alb/TGF-β were treated with either LY-2157299 (100 mg/kg/d) or vehicle daily by gastric lavage for 14 days. Blood counts were done on the 14th day and revealed a significant rise in hematocrit after LY-2157299 treatment. The mice were sacrificed and bone marrow biopsies were immunostained with an antibody against phosphor-SMAD2. Representative sample shows inhibition of SMAD2 activation after LY-2157299 treatment [3]. After oral administration of 75 mg/kg, LY2157299 induced a 70% decrease in pSmad for both types of cell lines. The time at which pSmad recovered 80% of baseline was approximately 6 h after administration [4].

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].