[Effect of SLC7A11 gene downregulation on the gefitinib resistance of lung adenocarcinoma PC9/GR cells and its mechanism].

Objective: To screen the key genes involved in gefitinib resistance of lung adenocarcinoma PC9/GR cells which harbored 19 exon mutation of epidermal growth factor receptor (EGFR) gene, and discuss the effect and mechanism of downregulation of solute carrier family 7 member 11 (SLC7A11) on the gefitinib resistance of PC9/GR cells. Methods: RNA microarray was conducted to detect the gene expressions in PC9 and PC9/GR cells. The differently expressed genes were screened by using limma package of R language and analyzed by Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis. Western blotting was performed to determine the expression of SLC7A11 protein in PC9 and PC9/GR cells. PC9/GR cells were infected with lentivirus plasmid containing short hairpin RNA (shRNA) targeting SLC7A11 or negative control shRNA (sh-NC), respectively. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed to evaluate the efficacy of shRNA on the expression of SLC7A11 mRNA. Cell counting kit-8 (CCK-8) assay was conducted to determine the suppressing effect of gefitinib on PC9/GR cells. Mito-Tracker Red CMXRos probe and malondialdehyde (MDA) assay kit were used to evaluate gefitinib-induced ferroptosis in PC9/GR cells. Immunohistochemistry (IHC) was conducted to detect the expression of SLC7A11 protein in the tumor tissues of advanced stage lung adenocarcinoma patients harboring 19 exon mutation of EGFR gene. Thirty-six advanced stage lung adenocarcinoma patients who received EGFR-tyrosihe kinase inhibitor(TKI) as first-line treatment in Fourth Hospital of Hebei Medical Unviersity were enrolled. Kaplan-Meier survival curve was drawn to analyze the correlation between SLC7A11 expression and progression-free survival (PFS) of the patients. Results: RNA array demonstrated that 2 888 genes were differently expressed between PC9 and PC9/GR cells. KEGG analysis showed that ferroptosis-related gene was one of the most enriched region of the differently expressed genes between PC9 and PC9/GR cells. These ferroptosis-related gene cohort contained 13 genes, among which SLC7A11 exhibited the most significant difference. Western blotting showed that the expression of SLC7A11 protein in PC9/GR cells was significantly higher than that in PC9 cells (0.76±0.03 vs. 0.19±0.02, P<0.001). The 50% inhibiting concentration (IC(50)) of gefitinib was 35.08 µmol/L and 64.01 µmol/L for sh-SLC7A11 and sh-NC group PC9/GR cells, respectively. PC9/GR cells in sh-SLC7A11 group exhibited significantly lower density of mitochondria fluorescence after gefitinib treatment, compared to the sh-NC group (213.77±26.50 vs. 47.88±4.55, P<0.001). In addition, PC9/GR cells in sh-SLC7A11 group exhibited significantly higher MDA after gefitinib treatment, compared to the sh-NC group [(15.43±1.60) µmol/mg vs. (82.18±7.77) µmol/mg, P<0.001]. The PFS of the patients with low expression of SLC7A11 (n=18) was significantly longer than the patients with high expression of SLC7A11 (n=18, 16.77 months vs. 9.14 months, P<0.001). Conclusion: Downregulation of SLC7A11 could increase the sensitivity of PC9/GR cells to gefitinib by promoting ferroptosis.

Rapid arrest of seizures with an inhalation aerosol containing diazepam.

Diazepam (DZP) and a mixture of Chinese herbs customarily used to treat epilepsy were prepared as an aerosol under the trade name Aerosolum Diaiepami Compositae or Flvalscop (FVS). FVS was studied in a single-blind trial in 101 patients with seizures preceded by an aura and in 19 without an aura to whom was administered by another person. FVS or a control preparation was administered. In 16-22 s, (average 18.5 s), the aura was interrupted and no seizure ensued in 90% of the cases treated with FVS and in 26% of cases treated with the control preparation. Of the 120 patients, 8 had elementary partial seizures with Jacksonian march, 18 had complex partial seizures (CPS), 7 had simple partial seizures with autonomic symptoms, and 87 had secondarily generalized tonic-clonic seizures. Eleven patients have now received FVS for 2 years (400 ml each). Forty patients for 1 year (150-200 ml each); none of these patients have shown any side effects or abnormal laboratory findings. An aerosol-administered drug may be a valuable adjunct to the antiepileptic drug (AED) arsenal and merits more extensive evaluation.