Caffeine activates preferentially α1-isoform of 5'AMP-activated protein kinase in rat skeletal muscle.

[Aim]: Caffeine activates 5′AMP-activated protein kinase (AMPK), a signalling intermediary implicated in the regulation of glucose, lipid and energy metabolism in skeletal muscle. Skeletal muscle expresses two catalytic α subunits of AMPK, α1 and α2, but the isoform specificity of caffeine-induced AMPK activation is unclear. The aim of this study was to determine which α isoform is preferentially activated by caffeine in vitroand in vivo using rat skeletal muscle. [Methods]: Rat epitrochlearis muscle was isolated and incubated in vitro in the absence or presence of caffeine. In another experiment, the muscle was dissected after intravenous injection of caffeine. Isoform-specific AMPK activity, the phosphorylation status of AMPKα Thr172 and acetyl-CoA carboxylase (ACC) Ser79, the concentrations of ATP, phosphocreatine (PCr) and glycogen, and 3-O-methyl-D-glucose (3MG) transport activity were estimated. [Results]: Incubation of isolated epitrochlearis muscle with 1 mM of caffeine for 15 min increased AMPKα1 activity, but not AMPKα2 activity; concentrations of ATP, PCr and glycogen were not affected. Incubation with 3 mM of caffeine activated AMPKα2 and reduced PCr and glycogen concentrations. Incubation with 1 mM of caffeine increased the phosphorylation of AMPK and ACC and enhanced 3MG transport. Intravenous injection of caffeine (5 mg kg−1) predominantly activated AMPKα1 and increased 3MG transport without affecting energy status. [Conclusion]: Our results suggest that of the two α isoforms of AMPK, AMPKα1 is predominantly activated by caffeine via an energy-independent mechanism and that the activation of AMPKα1 increases glucose transport and ACC phosphorylation in skeletal muscle

Is the Efficacy of Adding Ramucirumab to Docetaxel Related to a History of Immune Checkpoint Inhibitors in the Real-World Clinical Practice?

Reports on the efficacy of second-line treatment with cytotoxic agents after treatment with immune checkpoint inhibitors are limited. Here, we retrospectively evaluated patients in the real-world clinical practice treated with docetaxel or docetaxel plus ramucirumab. Ninety-three patients treated with docetaxel or docetaxel plus ramucirumab as a second- or later-line therapy were included. The patients were categorized into the following four treatment groups: docetaxel group (n = 50), docetaxel/ramucirumab group (n = 43) and pretreated (n = 45) and untreated (n = 48) with immune checkpoint inhibitor groups. The docetaxel/ramucirumab group showed an overall response rate of 57.1% in patients pretreated with immune checkpoint inhibitors and 20% in untreated patients. The docetaxel group showed an overall response rate of 15.4% in patients pretreated with immune checkpoint inhibitors and 5.0% in untreated patients. The median time-to-treatment failure and the median survival time were longer in the docetaxel/ramucirumab group than in the docetaxel group in both immune checkpoint inhibitor-pretreated and -untreated groups. There was no difference in time-to-treatment failure and overall survival between immune checkpoint inhibitor-pretreated and -untreated groups in each docetaxel and docetaxel/ramucirumab treatment group. In conclusion, our real-world data show that the addition of ramucirumab to docetaxel was superior to docetaxel monotherapy for improving time-to-treatment failure and overall survival, irrespective of previous treatment with immune checkpoint inhibitors