Notes: This study investigated the role of phosphatidylinositol 3-kinase on expression of the cardiac heat shock protein 72 (HSP72) in the normal and diabetic heart. In cultured neonatal rat cardiomyocytes prepared from Wistar rats, LY294002 inhibited hyperthermia-induced HSP72 expression and phosphorylation of Akt. (3535)

Notes: This study investigated the signaling mechanisms involved in 17β-estradiol- (E2) and tamoxifen-induced release of neurotrophic factors from rat cortical astrocyte cultures. The TGFβ1, TGFβ2, BDNF and GDNF E_max^® ImmunoAssay Systems were used to measure the release of these neurotrophic factors from astrocyte cultures treated with E2 or tamoxifen. Both E2 and tamoxifen induced the release of TGFβ1 and TGFβ2, but did not stimulate release of BDNF or GDNF. The PI3K inhibitors LY294002 and wortmanin, and the Akt inhibitor blocked TGFβ release, suggesting the involvement of the PI3K/Akt signaling pathway. The MAPK kinase inhibitors PD98059 and U0126 had no effect. E2 was found to induce transient Akt ^Ser473 phosphorylation, and this effect was blocked by LY294002 pretreatment, demonstrating a role for PI3K in the observed E2-mediated Akt phosphorylation. (3479)

Notes: The LY294002 phosphatidylinositol 3-kinase (PI3K) inhibitor was used to identify Nonsteroidal Anti-inflammatory Drug-activated Gene (NAG-1) as a novel downstream target of the PI3K pathway during cell activation. For these experiments, HCT-116 cells were treated with 50μM LY294002 and NAG-1 protein expression was assessed by Western blotting. Gene upregulation during LY294002 treatment was measured with a luciferase reporter construct containing the NAG-1 promoter, the pRL-null Vector as a transfection control, and the Dual-Luciferase^® Reporter Assay System. (3262)