Demethylation of gene promoter by propofol promotes autophagy of human A549 cells.

Propofol (2,6-diisopropylphenol) is one of the most commonly used intravenous anesthetics and possesses a number of non-anesthetic effects, including antitumor function. The aim of the present study was to elucidate the antitumor molecular mechanism of propofol on A549 and H1299 cells. A549 and H1299 cells were treated in the presence or absence of different concentrations (0, 60 or 120 µmol) of propofol for different durations (0, 24, 48 or 72 h), and proliferation was detected by MTT and colony formation assays; the protein levels of optineurin (OPTN) ubiquitination, HECT domain and ankyrin repeat containing E3 ubiquitin protein ligase 1 (HACE1), methyl-CpG binding domain protein 3 (MBD3) and Microtubule-associated protein 1A/1B-light chain 3 were detected by immunoblotting or quantitative (q)PCR; the methylation state of the gene promoter was detected by bisulfite DNA sequencing; and binding of MBD3 on gene promoter was detected by chromatin immunoprecipitation-qPCR. Propofol inhibited proliferation of A549 and H1299 cells and promoted HACE1-OPTN axis-mediated selective autophagy activity by increasing the protein expression levels of HACE1 via demethylating its promoter region. Furthermore, propofol promoted expression levels of MBD3 and binding to the -1,000 to -1 bp (transcription start site) region of gene promoter. MBD3-knockdown experiments indicated that propofol inhibited proliferation of A549 cells in a MBD3-dependent manner. Thus, the findings of the present study provided a potential antitumor molecular mechanism mediated by propofol.