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Background: The aim of this study was to evaluate the effect of ligustrazine on the apoptosis of A549 cells and clarify the mechanism of ligustrazine-induced apoptosis. Methods: Ligustrazine was prepared with medium according to the gradient concentration. Based on a cytotoxicity test, 3 different concentrations of ligustrazine were selected to form low, medium, and high groups, with a 0 mg/mL dose used as the control. The apoptosis degree and Fas (Fas cell surface death receptor) and Fas-L (Fas Ligand) expression were detected by flow cytometry and quantitative polymerase chain reaction (qPCR), respectively; meanwhile, the activity of caspase 8 and caspase 3 was analyzed by enzyme-linked immunosorbent assay (ELISA) and qPCR, respectively. Results: After 24 hours of ligustrazine administration, the survival rate of A549 cells decreased with the increase of drug concentration, while the rate of apoptosis increased with the increase of drug concentration. Meanwhile, Fas and Fas-L expression was found to be significantly increased at both the gene and protein level, which was positively correlated with drug concentration. Furthermore, the expression of caspase 8 and caspase 3 was positively correlated with the concentration of ligustrazine, and there was significant difference compared with the control group. Conclusions: Ligustrazine can induce the apoptosis of A549 cells via the upregulation of Fas- and caspase-activating death receptor pathway expression.
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Background: N6-methyladenosine (m6A) RNA regulators play important roles in cancers, but their functions and mechanism have not been demonstrated clearly in gastric cancer (GC). Methods: In this study, the GC samples with clinical information and RNA transcriptome were downloaded from The Cancer Genome Atlas database. The different expression genes were compared by the absolute value and median ± standard deviation. Samples with complete information were randomly divided into a training dataset and a test dataset. The differential expression genes (DEGs) between ALKBH5-low and ALKBH5-high subgroups were identified in the training dataset and constructed a risk model by Cox and least absolute shrinkage and selection operator regression. The model was testified in test datasets, overall survival (OS) was compared with the Kaplan-Meier method, and immune cell infiltration was calculated by the CIBERSORT algorithm in the low-risk and high-risk subgroups based on the model. The protein levels of ALKBH5 were detected with immunohistochemistry. The relative expression of messenger-ribonucleic acid (mRNA) was detected with quantitative polymerase chain reaction. Results: ALKBH5 was the only regulator whose expression was lower in tumor samples than that in normal samples. The low expression of ALKBH5 led to the poor OS of GC patients and seemed to be an independent protective factor. The model based on ALKBH5-regulated genes was validated in both datasets (training/test) and displayed a potential capacity to predict a clinical prognosis. Gene Ontology analysis implied that the DEGs were involved in the immune response; CIBERSORT results indicated that ALKBH5 and its related genes could alter the immune microenvironment of GC. The protein levels of ALKBH5 were verified as lowly expressed in GC tissues. SLC7A2 and CGB3 were downregulated with ALKBH5 knockdown. Conclusions: In this study, we found that ALKBH5 might be a suppressor of GC; ALKBH5 and its related genes were latent biomarkers and immunotherapy targets.
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[This corrects the article DOI: 10.18632/oncotarget.23249.].
ABSTRACT
Numerous studies have shown drug resistance of gastric cancer cells could be modulated by abnormal expression of microRNAs. Cisplatin (DDP) is one of the most commonly used drugs for chemotherapy of gastric cancer. In this study, the potential function of miR-125b on DDP resistance in gastric cancer cells was investigated. Sixteen miRNAs significantly differential expressed in gastric tumor tissues and adjacent tissues were characterized and their corresponding putative target genes were also screened. MiR-125b was selected as our focus for its evident down-regulated expression among candidate genes. Real-time polymerase chain reaction assay indicated that miR-125b was significantly down-regulated in gastric cancer tissues and various cell lines. HER2 was identified as a target gene of miR-125b by dual luciferase reporter assay and Western blot. Moreover, miR-125b overexpression inhibited not only the proliferation, migration, and invasion abilities of HGC-27 and MGC-803 cells, but also in vivo tumor growth of MGC-803 cells by an intratumoral delivery approach. Notably, we observed up-regulated miR-125b contributed to the chemosensitivity of DDP in HGC-27 and MGC-803 cells at different concentrations and also possessed sensibilization for DDP at different times. MiR-125b expression was found to be related to lymph node metastasis, HER2 expression and overall survival of patients through correlation analysis. Collectively, these results indicate miR-125b may regulate DDP resistance as a promising therapeutic target for gastric cancer treatment in future.
