Regulatory effects of anandamide on intracellular Ca^(2+) concentration increase in trigeminal ganglion neurons

Activation of cannabinoid receptor type 1 on presynaptic neurons is postulated to suppress neu- ~ ~ ~ 2＋ ~ ~ 2＋ rotransmlsslon by decreasing Ca reflux through high voltage-gated Ca channels. However, recent studies suggest that cannabinoids which activate cannabinoid receptor type 1 can increase neurotransmitter release by enhancing Ca2＋ influx in vitro. The aim of the present study was to investigate the modulation of intracellular Ca2＋ concentration by the cannabinoid receptor type 1 agonist anandamide, and its underlying mechanisms. Using whole cell voltage-damp and calcium imaging in cultured trigeminal ganglion neurons, we found that anandamide directly caused Ca2＋ influx in a dose-dependent manner, which then triggered an increase of intracellular Ca2＋ concentration. The cyclic adenosine and guanosine monophosphate-dependent protein kinase systems, but not the protein kinase C system, were involved in the increased intracellular Ca2＋concentration by anandamide. This result showed that anandamide increased intracellu- lar Ca2＋ concentration and inhibited high voltage-gated Ca2＋ channels through different signal transduction pathways.

Sorafenib sensitization in tumor therapy by iron overload and AMPK activation

Sorafenib,as a first-line drug for advanced hepatocellular carcinoma(HCC),could trigger ferroptosis by inhibiting cystine/glutamate transporter.However,low-level intracellular iron and insufficient activation of adenosine monophosphate(AMP)-activated protein kinase(AMPK)confer impaired response to sorafenib.In this study,a unique sorafenib nanocomposite dexterously modified with Fe-Material of Institut Lavoisier(sora@Fe-MIL)was synthesized to escalate intracellular iron level and activate AMPK,further potentiating the ferroptotic effect of sorafenib.Remarkably,this strategic deployment of sora@Fe-MIL triggered an extensive demise of cancer cells,while manifesting negligible deleterious impact on normal cells.Two prominent ferroptosis biomarkers,glutathione peroxidase 4(GPX4)and solute carrier family 7 member 11(SLC7A11),underwent pronounced downregulation,underscoring the efficacy of this strategy in inducing ferroptosis.Furthermore,the bioactivity of AMPK was considerably elevated,and its downstream targets were conspicuously inhibited by the treatment with sora@Fe-MIL.Using orthotopic HCC animal models,we observed a substantial suppression of primary in situ tumor growth,and ribonucleic acid(RNA)sequencing elucidated an elevated degree of ferroptosis and AMPK activation with the treatment of sora@Fe-MIL.In conclusion,we proposed that the meticulously designed strategy for secure and efficacious iron release and AMPK activation could significantly potentiate the ferroptotic impact of sorafenib,thus resuscitating its therapeutic response in HCC patients.