Versatile prostate cancer treatment with inducible caspase and interleukin-12.

To establish optimized conditions for immunity against prostate cancer, we compared the efficacy of multiple approaches in autochthonous and s.c. transgenic adenocarcinoma of the mouse prostate (TRAMP)-based models. Mice immunized with interleukin (IL)-12-containing apoptotic, but not necrotic TRAMP-C2 cell-based, vaccines were resistant to TRAMP-C2 tumor challenge and re-challenge, independently of the route of vaccination (s.c. or i.p.). Administration of gamma-irradiated TRAMP-C2 cells preinfected with adenovirus containing both B7-1 and IL-12 genes, unlike adenovirus containing B7-1 alone, considerably protected C57BL/6 mice from TRAMP-C2 tumor growth and extended the life span of TRAMP mice. Vaccines that included dendritic cells, instead of IL-12, were equally efficient. Whereas injections of ligand-inducible caspase-1- and IL-12-containing adenoviruses cured small s.c. TRAMP-C2 tumors, nanopump-regulated delivery of viruses led to elimination of much larger tumors. The antitumor immune responses involved CD4+-, CD8+-, and natural killer cells and were strengthened by increasing the number of vaccinations. Intraprostatic administration of inducible caspase-1- and IL-12-containing adenoviruses resulted in local cell death and improved survival of adenocarcinoma-bearing TRAMP mice. Thus, tumor cell apoptosis induced by caspase in situ and accompanied by IL-12 is efficient against prostate cancer in a preclinical model.

Sorafenib downregulates ERK/Akt and STAT3 survival pathways and induces apoptosis in a human neuroblastoma cell line.

Neuroblastoma is a common solid tumor in children and its tumorigenicity is enhanced by the expression of survival pathways such as Akt and signal transducer and activator of transcription 3 (STAT3). Sorafenib is a multikinase inhibitor that also inhibits STAT3 signaling and induces apoptosis. In this study, we will examine the efficacy of sorafenib on a human neuroblastoma cell line (SK-N-AS) and also investigate its possible mechanisms. After cells reached 50-60% confluence, they were treated with various concentrations of sorafenib (0, 0.1, 1, 5, 10 and 20 microM) for different periods of time. The cell viability and apoptosis were determined by MTS colorimetric assay and TUNEL, respectively. Phosphorylation of Akt1/2/3 (p-Akt1/2/3), extracellular signal-regulated kinase 1/2 (p-ERK1/2), STAT3 (p-STAT3), and AMP-activated protein kinase alpha subunit (p-AMPKalpha) were determined with Western blot. The results indicate that as early as 2 hours post-treatment, cell viability was significantly decreased at 10 microM concentration. In 24 hours or longer treatment groups, sorafenib at 5 microM and above significantly decreased cell viability. TUNEL assay showed a significant increased of apoptosis in 5 and 20 microM treatment groups 24 hours after treatment. Western blots showed a decrease of p-ERK1/2, p-Akt1/2/3, p-STAT3, and p-AMPKalpha expression levels in various sorafenib treatment groups. Our results indicate that sorafenib significantly decreased cell viability and increased apoptosis in human neuroblastoma cell line in association with down-regulation of p-ERK1/2, p-Akt, p-STAT3 survival pathways. These data suggested potential clinical application of sorafenib in the treatment of neuroblastoma.

Poloxamer 188 inhibition of ischemia/reperfusion injury: evidence for a novel anti-adhesive mechanism.

Poloxamer 188 (P188) is a nonionic block copolymer surfactant that has rheologic, anti-thrombotic, anti-inflammatory, and cytoprotective activities. Several mechanisms have previously been proposed, but none explain all of the observed effects. In this study, superior mesenteric artery occlusion (SMAO) was employed as a clinically relevant model of ischemia/reperfusion. The superior mesenteric artery of rats was clamped for one hr and and followed by reperfusion with P188 or saline for five hr, after which tissues were harvested for expression microarray, histologic, enzymatic, and western blot analyses. The results demonstrated that P188 significantly inhibits the entire spectrum of inflammatory, coagulation, and apoptotic responses produced by SMAO. This supports the existence of a novel mechanism that recognizes two types of adhesive interactions. The first, specific receptor-ligand adhesion, governs interactions between cells and molecules and is unaffected by P188. P188 affects only the second type, hydrophobic adhesion, which is responsible for the integrity of membranes and conformation of proteins. Hydrophobic interactions are non-specific because they derive from repulsion of water rather than from affinity of molecules for one another. Ischemic membranes develop defects that expose underlying hydrophobic structures and trigger multiple deleterious responses. Fat emboli and hydrophobic proteins such as fibrin produced by the injury further compromise the microcirculation. The unique structure of P188 facilitates its rapid, but gentle, binding to any exposed hydrophobic domain, restoring normal non-adhesive surfaces and thereby preventing activation of the entire spectrum of deleterious reactions.