sotrastaurin and Disease-Models--Animal

G-protein mutations are one of the most common mutations occurring in uveal melanoma activating the protein kinase C (PKC)/mitogen-activated protein kinase and phosphoinositide 3-kinase (PI3K)/AKT pathways. In this study, we described the effect of dual pathway inhibition in uveal melanoma harboring GNAQ and GNA11 mutations via PKC inhibition with AEB071 (sotrastaurin) and PI3K/AKT inhibition with BYL719, a selective PI3Kα inhibitor. Growth inhibition was observed in GNAQ/GNA11-mutant cells with AEB071 versus no activity in wild-type cells. In the GNAQ-mutant cells, AEB071 decreased phosphorylation of myristoylated alanine-rich C-kinase substrate, a substrate of PKC, along with ERK1/2 and ribosomal S6, but persistent AKT activation was present. BYL719 had minimal antiproliferative activity in all uveal melanoma cell lines, and inhibited phosphorylation of AKT in most cell lines. In the GNA11-mutant cell line, similar effects were observed with ERK1/2 inhibition, mostly inhibited by BYL719. With the combination treatment, both GNAQ- and GNA11-mutant cell lines showed synergistic inhibition of cell proliferation and apoptotic cell death. In vivo studies correlated with in vitro findings showing reduced xenograft tumor growth with the combination therapy in a GNAQ-mutant model. These findings suggest a new therapy treatment option for G-protein-mutant uveal melanoma with a focus on specific targeting of multiple downstream pathways as part of combination therapy.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Survival; Class I Phosphatidylinositol 3-Kinases; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Gene Silencing; GTP-Binding Protein alpha Subunits; GTP-Binding Protein alpha Subunits, Gq-G11; Humans; Melanoma; Mice; Mutation; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase C; Pyrroles; Quinazolines; RNA Interference; Signal Transduction; Thiazoles; Tumor Burden; Uveal Neoplasms; Xenograft Model Antitumor Assays

AEB071 (sotrastaurin) is a specific inhibitor of protein kinase C that prevents T-cell activation. Our previous study demonstrated that AEB071 monotherapy could prevent acute cardiac allograft rejection in rats. Herein, we investigated the effects of AEB071 combined with various doses of tacrolimus (Tac) on the allograft rejection and survival in a rat heart transplantation model.. Heterotopic cardiac transplantation from Brown-Norway to Lewis rats was performed. Cardiac allograft survival was assessed by monitoring heartbeats in six recipients of each experimental group. Another four recipient rats were selectively sacrificed in each group at d 7 post-transplantation for histologic examination. Serum transaminases, blood urea nitrogen, and creatinine concentrations were measured.. AEB071 monotherapy prolonged allograft mean survival time (MST) compared with the untreated control group. Also a combination of AEB071 and Tac prolonged MST compared with monotherapy groups with higher dose of Tac. In the cardiac graft histology, AEB071 combined with Tac 0.6 mg/kg/d significantly decreased the rejection grade as indicative of decreased inflammatory cell infiltration into the graft. No experimental group was found with any abnormal histologic or serologic evidence of liver and kidney toxicity.. AEB071 combined with a smaller dosage of Tac may be clinically possible to establish calcineurin inhibitor (CNI) minimization protocol in solid organ transplantation.

Topics: Acute Disease; Animals; Disease Models, Animal; Drug Therapy, Combination; Graft Rejection; Graft Survival; Heart Transplantation; Immunosuppressive Agents; Kidney; Liver; Male; Protein Kinase Inhibitors; Pyrroles; Quinazolines; Rats; Rats, Inbred BN; Rats, Inbred Lew; Tacrolimus; Transplantation, Heterotopic; Transplantation, Homologous