Zhou Yubin, Khawkhiaw Kullanat, Thithuan Kanyarat, Saengboonmee Charupong
Department of Thoracic Surgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, P.R. China.
Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
Anticancer Res. 2025 Apr;45(4):1513-1523. doi: 10.21873/anticanres.17533.
BACKGROUND/AIM: The roles of γ-aminobutyric acid (GABA) and its receptors in lung cancer development and progression remain controversial. This study aimed to investigate the effects of activating GABA receptor type B (GABA-B receptor) using baclofen, a GABA-B receptor agonist, on the proliferation of lung adenocarcinoma cells and its underlying mechanisms.
Differential expression of GABA-B receptors was analyzed using the online Gene Expression Profiling Interactive Analysis tool. Lung adenocarcinoma cell lines, A549 and PC-9, were cultured in RPMI-1640 medium and used for experiments. Effects of baclofen on cancer cell proliferation were determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Mechanisms of how baclofen inhibits cell proliferation were determined using flow cytometry and western blots.
The expression of GABA-B1 receptor was down-regulated in lung adenocarcinoma compared with normal lung tissues, while GABA-B2 receptor expression was not different between cancer and normal samples. Baclofen significantly inhibited the proliferation of lung adenocarcinoma cells in a dose-dependent manner in both cell lines. Flow cytometry suggested that cancer cells were arrested at the G phase of the cell cycle after being treated with baclofen. Thus, the expression of proteins of the G cell cycle machinery, namely cyclin D1, cyclin E, cyclin-dependent kinase (CDK) 4, and CDK6, were significantly suppressed. The phosphorylation of CDK2 was also suppressed after baclofen treatment. Moreover, baclofen treatment increased phosphorylated glycogen synthase kinase 3 (GSK3) levels, suggesting inhibition of carcinogenic GSK3 signaling pathway in lung adenocarcinoma.
GABA-B1 receptors were down-regulated in lung adenocarcinoma cells. Non-specific activation of the GABA-B receptor by baclofen significantly inhibited lung adenocarcinoma cell proliferation by cell cycle arrest and suppressed the GSK3 signaling pathway.
背景/目的：γ-氨基丁酸（GABA）及其受体在肺癌发生发展中的作用仍存在争议。本研究旨在探讨使用GABA-B受体激动剂巴氯芬激活GABA-B受体对肺腺癌细胞增殖的影响及其潜在机制。
使用在线基因表达谱交互式分析工具分析GABA-B受体的差异表达。将肺腺癌细胞系A549和PC-9培养于RPMI-1640培养基中并用于实验。使用3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐法测定巴氯芬对癌细胞增殖的影响。使用流式细胞术和蛋白质免疫印迹法确定巴氯芬抑制细胞增殖的机制。
与正常肺组织相比，肺腺癌中GABA-B1受体的表达下调，而GABA-B2受体在癌组织和正常样本中的表达无差异。巴氯芬在两种细胞系中均以剂量依赖的方式显著抑制肺腺癌细胞的增殖。流式细胞术表明，用巴氯芬处理后癌细胞停滞在细胞周期的G期。因此，表示G细胞周期机制的蛋白，即细胞周期蛋白D1、细胞周期蛋白E、细胞周期蛋白依赖性激酶（CDK）4和CDK6的表达被显著抑制。巴氯芬处理后CDK2的磷酸化也受到抑制。此外, 巴氯芬处理增加了磷酸化糖原合酶激酶3（GSK3）的水平，提示对肺腺癌中致癌性GSK3信号通路的抑制。
肺腺癌细胞中GABA-B1受体下调。巴氯芬对GABA-B受体的非特异性激活通过细胞周期停滞显著抑制肺腺癌细胞增殖，并抑制GSK3信号通路。
