Isoflurane activates AMP-activated protein kinase to inhibit proliferation, and promote apoptosis and autophagy in cervical carcinoma both in vitro and in vivo

Abstract

Objective Isoflurane is an extensively used inhalational anesthesia, and its carcinogenic or anti-cancerous effect has been identified recently. However, the specific role of isoflurane in cervical cancer remains unclear. Aim This study aimed to investigate the function of isoflurane in cervical cancer as well as the underlying mechanism. Methods After isoflurane treatment, HeLa cell viability, percentage of apoptotic cells, expression of active caspase-3/9 were examined by CCK-8 assay, Annexin V-FITC/PI double staining, and Western blot analysis, respectively. ROS generation, ratio of NAD+/NADH, and ATP level after isoflurane stimulation were determined using commercial assay kits. Afterwards, activation of AMPK and autophagy was assessed through Western blot analysis and immunofluorescence. Whether AMPK mediated the isoflurane-induced apoptosis and autophagy was explored by adding an AMPK inhibitor (Compound C). The in vivo function of isoflurane was finally investigated on a HeLa cell xenograft model. Results Isoflurane inhibited cell viability and induced apoptosis evidenced by upregulation of active caspase-3/9 in HeLa cells. Oxidative stress was triggered by isoflurane, as isoflurane elevated ROS level, and lowered ratio of NAD+/NADH and ATP level. Further results showed isoflurane activated the AMPK/mTOR pathway and induced autophagy. In addition, inhibition of AMPK led to ameliorated effects of isoflurane on apoptosis and autophagy. In vivo experiments proved isoflurane could repress tumorigenesis, activate AMPK, and induce autophagy in Xenograft mouse. Conclusions Isoflurane activated AMPK to inhibit proliferation and promote apoptosis and autophagy both in vitro and in vivo.