Faculty of Education, Soran University, Erbil, Kurdistan Region, Iraq.
University of Reading, School of Biological Sciences, Reading, UK.
Cell Signal. 2021 May;81:109934. doi: 10.1016/j.cellsig.2021.109934. Epub 2021 Feb 3.
Lung cancer has a poor prognosis partly due to a lack of response to treatments such as the chemotherapy drug gemcitabine. Combinations of chemotherapy drugs with signal transduction inhibitors may be more effective treatments. In this study we have investigated the impact of targeting the mTOR signalling pathway on the efficacy of gemcitabine in different cancer cell lines.
Time-lapse microscopy, immuno-staining, and western blot techniques were used to evaluate the efficacy of applied treatments either in measuring phosphorylation levels of mTOR down-stream targets or in tracking down the fate of targeted cells. Reactive oxygen species and relative levels of protein phosphorylation were also quantified. For comparison between treated groups t-test and analysis of variance test were applied.
Our data showed that mTORC1 has no role in sensitising A549 lung cancer cells to gemcitabine. However, targeting mTORC1/2 with the pharmacological inhibitor torin1 or by over-expressing Deptor, the negative regulator of mTOR signalling, sensitised these cells to gemcitabine. Silencing mTORC2, but not mTORC1, induced apoptosis and significantly improved the apoptosis-inducing effects of gemcitabine. Results also suggest that Rictor is required to maintain cell survival through modulating p38α, ERK1/2, RSK1/2/3 and the transcription factor STAT3. Multiple cell line comparisons revealed that PANC-1 pancreatic cancer cells were also sensitive to mTOR inhibition, but MCF7 breast cancer, MCF10A breast epithelial and H727 lung cancer cell lines were more resistant to the treatment.
Inhibition of mTORC2 may have benefits in the treatment of gemcitabine resistant cancers, and the genetic background of the cell line may determine its response to mTOR inhibition.
肺癌预后较差，部分原因是对化疗药物吉西他滨等治疗反应不佳。化疗药物与信号转导抑制剂的联合应用可能是更有效的治疗方法。本研究探讨了靶向 mTOR 信号通路对不同癌细胞系中吉西他滨疗效的影响。
采用延时显微镜、免疫染色和 Western blot 技术，评估应用治疗方法在测量 mTOR 下游靶点磷酸化水平或跟踪靶向细胞命运方面的疗效。还定量测定了活性氧和蛋白质磷酸化的相对水平。为了比较处理组之间的差异，应用了 t 检验和方差分析检验。
我们的数据表明，mTORC1 对 A549 肺癌细胞对吉西他滨的增敏作用没有作用。然而，用药理学抑制剂 torin1 或过表达 mTOR 信号的负调节剂 Deptor 靶向 mTORC1/2，可使这些细胞对吉西他滨敏感。沉默 mTORC2，但不是 mTORC1，可诱导细胞凋亡，并显著增强吉西他滨的促凋亡作用。结果还表明，Rictor 通过调节 p38α、ERK1/2、RSK1/2/3 和转录因子 STAT3 来维持细胞存活。对多种细胞系的比较表明，PANC-1 胰腺癌细胞也对 mTOR 抑制敏感，但 MCF7 乳腺癌、MCF10A 乳腺上皮和 H727 肺癌细胞系对该治疗更耐药。
抑制 mTORC2 可能对吉西他滨耐药癌症的治疗有益，而细胞系的遗传背景可能决定其对 mTOR 抑制的反应。
