title: Alpha 7-nicotinic acetylcholine receptor mediates the sensitivity of gastric cancer cells to 5-fluorouracil.
abstract: Gastric cancer is the second most common cause of cancer mortality worldwide. Most gastric cancer patients are asymptomatic until the advanced stages, for which current therapeutic treatments are suboptimal. 5-Fluorouracil (5-FU), an antimetabolite agent, is widely used in gastric cancer therapy. However, the presence of drug resistance in gastric cancer patients reduces the cytotoxic activity of 5-FU. In gastric cancer, no research has yet been conducted to analyze the effect of alpha 7-nicotinic acetylcholine receptor (A7-nAChR) on the therapeutic response to 5-FU. In this study, we generated A7-nAChR knockdown (A7-nAChR-KD) AGS cells by a small interfering RNA (siRNA) technique in gastric cancer cells. The anti-proliferative effects of 5-FU were determined by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, a terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay, and cell cycle determination. We found that A7-nAChR-KD cells were more resistant to 5-FU treatment compared with the scrambled control cells according to the MTT assay. The apoptotic cell population was increased more in scrambled control cells treated with 5-FU than A7-nAChR-KD cells according to the cell cycle distribution and TUNEL assays. We analyzed expression levels of survival and apoptosis-associated proteins (pAkt, Akt, Mcl-1, Bcl-2, Bad, and Bax) altered by 5-FU treatment. Survival and antiapoptosis signaling (pAkt, Akt, Mcl-1 and Bcl-2) was downregulated, and the proapoptotic proteins (Bad and Bax) were upregulated in 5-FU-treated control cells but expression levels of Bcl-2, Bad, and Bad were not altered in 5-FU-treated A7-nAChR-KD cells. This is consistent with A7-nAChR-KD cells exhibiting more resistance to 5-FU treatment. In our study, we carried out an in vitro study on AGS gastric cancer cell line to elucidate the anticancer efficacy and molecular mechanisms of A7-nAChR silencing on 5-FU-induced cell death. The results clearly showed that depletion of A7-nAChR suppressed the drug sensitivity of gastric cancer cells to 5-FU treatment.
authors.affiliation: Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, 250 Wu-Xing Street, Taipei City, 110, Taiwan.|Department of Pathology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.|Department of Pathology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.
authors.forename: Wei-Yu
authors.initials: WY
authors.lastname: Chen
authors.affiliation: Division of General Surgery, Department of Surgery, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan.|Department of Neurosurgery, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan.
authors.forename: Chien-Yu
authors.initials: CY
authors.lastname: Huang
authors.affiliation: Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Wan-Li
authors.initials: WL
authors.lastname: Cheng
authors.affiliation: Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, 250 Wu-Xing Street, Taipei City, 110, Taiwan.|Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.|Division of General Surgery, Department of Surgery, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan.|Cancer Research Center, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan.
authors.forename: Chin-Sheng
authors.initials: CS
authors.lastname: Hung
authors.affiliation: Division of General Surgery, Department of Surgery, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan.|Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.|Division of General Surgery, Department of Surgery, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan.
authors.forename: Ming-Te
authors.initials: MT
authors.lastname: Huang
authors.affiliation: Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.|Division of Hematology and Oncology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan.
authors.forename: Cheng-Jeng
authors.initials: CJ
authors.lastname: Tai
authors.affiliation: Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.
authors.forename: Yen-Nien
authors.initials: YN
authors.lastname: Liu
authors.affiliation: Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, 250 Wu-Xing Street, Taipei City, 110, Taiwan.|Department of Pathology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.|Department of Pathology, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan.
authors.forename: Chi-Long
authors.initials: CL
authors.lastname: Chen
authors.affiliation: Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, 250 Wu-Xing Street, Taipei City, 110, Taiwan. r5424012@tmu.edu.tw.|Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan. r5424012@tmu.edu.tw.|Division of General Surgery, Department of Surgery, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan. r5424012@tmu.edu.tw.|Cancer Research Center, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan. r5424012@tmu.edu.tw.
authors.forename: Yu-Jia
authors.initials: YJ
authors.lastname: Chang
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005472:Fluorouracil / Q000008:administration & dosage*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2; D015398:Signal Transduction / Q000187:drug effects; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D064569:alpha7 Nicotinic Acetylcholine Receptor / Q000037:antagonists & inhibitors / Q000235:genetics*
chemical_list: D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D064569:alpha7 Nicotinic Acetylcholine Receptor; D005472:Fluorouracil
keywords: 5-FU; 5-Fluorouracil; A7-nAChR; Gastric cancer