Patient demographics and clinical data for the 10 post-liver transplant patients and 9 control patients whose liver sections were analyzed for markers of apoptosis.

<p>Post-Tx: Post-liver transplant; Bx: Liver biopsy; Alb: Serum albumin; Bili: Serum bilirubin; ALT: Serum alanine transaminase; INR: International Normalized Ratio; CyA: Cyclosporine; Aza: Azathioprine; Tac: Tacrolimus; Pred: Prednisolone; MMF: Mycophenolate mofetil.</p><p>Patient demographics and clinical data for the 10 post-liver transplant patients and 9 control patients whose liver sections were analyzed for markers of apoptosis.</p

Tacrolimus at therapeutic concentrations does not affect hepatocyte cell death.

<p>(A) Percentage reduction in cell viability from crystal violet assays of PMoH treated with 0.005 μg/ml of tacrolimus at 24–72 hours compared to untreated cells. (B) Western blots of cleaved PARP and cleaved caspase 3 levels in PMoH treated with 0.005 μg/ml of tacrolimus at 48 hours compared to untreated cells. Graphs show fold change in cleaved PARP and cleaved caspase 3 levels in tacrolimus-treated PMoH relative to untreated cells. Each bar represents the average of 3 experiments and error bar represents SEM. P-values are compared to untreated hepatocytes.</p

The combination of tacrolimus and MMF promotes cell death in hepatocytes.

<p>(A) Percentage reduction in cell viability from crystal violet assays of PMoH treated with 0.005 μg/ml of tacrolimus ± 5 μg/ml of MMF or 1 μg/ml of cyclosporine + 5 μg/ml of MMF at 24–72 hours compared to untreated cells. (B) Western blots of cleaved PARP and cleaved caspase 3 levels in PMoH treated with 0.005 μg/ml of tacrolimus ± 5 μg/ml of MMF or 1 μg/ml of cyclosporine + 5 μg/ml of MMF at 48 hours compared to untreated cells. Graphs show fold change in cleaved PARP and cleaved caspase 3 levels in tacrolimus/MMF-treated PMoH and cyclosporine/MMF-treated cells compared to untreated hepatocytes. Each bar represents the average of 3 experiments and error bar represents SEM. P-values are compared to untreated hepatocytes.</p

The combination of sirolimus and mycophenolate mofetil has no significant effect on cell death in hepatocytes.

<p>(A) Percentage reduction in cell viability from crystal violet assays of PMoH treated with 0.01 μg/ml of sirolimus ± 5 μg/ml of MMF or 0.005 μg/ml of tacrolimus + 5 μg/ml of MMF at 24–72 hours compared to untreated cells. (B) Western blots of cleaved PARP and cleaved caspase 3 levels in PMoH treated with 0.01 μg/ml of sirolimus ± 5 μg/ml of MMF or 0.005 μg/ml of tacrolimus + 5 μg/ml of MMF at 48 hours compared to untreated cells. Graphs show fold change in cleaved PARP and cleaved caspase 3 levels in sirolimus/MMF-treated PMoH and tacrolimus/MMF-treated cells compared to untreated hepatocytes. Each bar represents the average of 3 experiments and error bar represents SEM. P-values are compared to untreated hepatocytes.</p

Sirolimus at therapeutic concentrations does not increase hepatocyte cell death.

<p>(A) Percentage reduction in cell viability from crystal violet assays of PMoH treated with 0.01 μg/ml of sirolimus at 24–72 hours compared to untreated cells. (B) Western blots of cleaved PARP and cleaved caspase 3 levels in PMoH treated with 0.01 μg/ml of sirolimus at 48 hours compared to untreated cells. Graphs show fold change in cleaved PARP and cleaved caspase 3 levels in sirolimus-treated PMoH compared to untreated cells. Each bar represents the average of 3 experiments and error bar represents SEM. P-values are compared to untreated hepatocytes.</p

Cyclosporine at therapeutic concentrations does not increase hepatocyte cell death.

<p>(A) Percentage reduction in cell viability from crystal violet assays of PMoH treated with 1 μg/ml of cyclosporine compared to untreated cells. (B) Western blots of cleaved PARP and cleaved caspase 3 levels in PMoH treated with 1 μg/ml of cyclosporine compared to untreated cells. Graphs show fold change in cleaved PARP and cleaved caspase 3 levels relative to untreated cells. Each bar represents the average of 3 experiments and error bar represents SEM. P-values are compared to untreated hepatocytes.</p

Mycophenolate mofetil reduces hepatocyte cell death in a dose-dependent manner.

<p>(A) Percentage increase in cell viability from crystal violet assays of PMoH treated with 5 μg/ml of MMF, compared to untreated cells. (B) Western blots of cleaved PARP and cleaved caspase 3 levels in PMoH treated with 5 μg/ml of MMF at 48 hours compared to untreated cells. Graphs show fold change in cleaved PARP and cleaved caspase 3 levels relative to untreated cells. Each bar represents the average of 3 experiments and error bar represents SEM. P-values are compared to untreated hepatocytes.</p

Birinapant, a Smac-Mimetic with Improved Tolerability for the Treatment of Solid Tumors and Hematological Malignancies

Birinapant (<b>1</b>) is a second-generation bivalent antagonist of IAP proteins that is currently undergoing clinical development for the treatment of cancer. Using a range of assays that evaluated cIAP1 stability and oligomeric state, we demonstrated that <b>1</b> stabilized the cIAP1-BUCR (BIR3-UBA-CARD-RING) dimer and promoted autoubiquitylation of cIAP1 in vitro. Smac-mimetic <b>1</b>-induced loss of cIAPs correlated with inhibition of TNF-mediated NF-κB activation, caspase activation, and tumor cell killing. Many first-generation Smac-mimetics such as compound <b>A</b> (<b>2</b>) were poorly tolerated. Notably, animals that lack functional cIAP1, cIAP2, and XIAP are not viable, and <b>2</b> mimicked features of triple IAP knockout cells in vitro. The improved tolerability of <b>1</b> was associated with (i) decreased potency against cIAP2 and affinity for XIAP BIR3 and (ii) decreased ability to inhibit XIAP-dependent signaling pathways. The P₂′ position of <b>1</b> was critical to this differential activity, and this improved tolerability has allowed <b>1</b> to proceed into clinical studies