Aoun Rita, El Hadi Christopher, Tahtouh Roula, El Habre Rita, Hilal George
Cancer and Metabolism Laboratory, Faculty of Medicine, Saint-Joseph University, Beirut, Lebanon.
Faculty of Medicine, Saint-Joseph University, Beirut, Lebanon.
Cancer Cell Int. 2022 Mar 19;22(1):123. doi: 10.1186/s12935-022-02542-w.
Breast cancer (BC) is the most frequently diagnosed cancer in women. Altering glucose metabolism and its effects on cancer progression and treatment resistance is an emerging interest in BC research. For instance, combining chemotherapy with glucose-lowering drugs (2-deoxyglucose (2-DG), metformin (MET)) or glucose starvation (GS) has shown better outcomes than with chemotherapy alone. However, the genes and molecular mechanisms that govern the action of these glucose deprivation conditions have not been fully elucidated. Here, we investigated the differentially expressed genes in MCF-7 and MDA-MB-231 BC cell lines upon treatment with glucose-lowering drugs (2-DG, MET) and GS using microarray analysis to study the difference in biological functions between the glucose challenges and their effect on the vulnerability of BC cells.
MDA-MB-231 and MCF-7 cells were treated with 20 mM MET or 4 mM 2-DG for 48 h. GS was performed by gradually decreasing the glucose concentration in the culture medium to 0 g/L, in which the cells remained with fetal bovine serum for one week. Expression profiling was carried out using Affymetrix Human Clariom S microarrays. Differentially expressed genes were obtained from the Transcriptome Analysis Console and enriched using DAVID and R packages.
Our results showed that MDA-MB-231 cells were more responsive to glucose deprivation than MCF-7 cells. Endoplasmic reticulum stress response and cell cycle inhibition were detected after all three glucose deprivations in MDA-MB-231 cells and only under the metformin and GS conditions in MCF-7 cells. Induction of apoptosis and inhibition of DNA replication were observed with all three treatments in MDA-MB-231 cells and metformin-treated MCF-7 cells. Upregulation of cellular response to reactive oxygen species and inhibition of DNA repair mechanisms resulted after metformin and GS administration in MDA-MB-231 cell lines and metformin-treated MCF-7 cells. Autophagy was induced after 2-DG treatment in MDA-MB-231 cells and after metformin in MCF-7 cells. Finally, inhibition of DNA methylation were observed only with GS in MDA-MB-231 cells.
The procedure used to process cancer cells and analyze their expression data distinguishes our study from others. GS had the greatest effect on breast cancer cells compared to 2-DG and MET. Combining MET and GS could restrain both cell lines, making them more vulnerable to conventional chemotherapy.
乳腺癌（BC）是女性中最常被诊断出的癌症。改变葡萄糖代谢及其对癌症进展和治疗抗性的影响是BC研究中一个新出现的关注点。例如，将化疗与降糖药物（2-脱氧葡萄糖（2-DG）、二甲双胍（MET））或葡萄糖饥饿（GS）联合使用已显示出比单独使用化疗更好的效果。然而，调控这些葡萄糖剥夺条件作用的基因和分子机制尚未完全阐明。在此，我们使用微阵列分析研究了降糖药物（2-DG、MET）和GS处理后MCF-7和MDA-MB-231 BC细胞系中差异表达的基因，以研究葡萄糖挑战之间生物学功能的差异及其对BC细胞易感性的影响。
用20 mM MET或4 mM 2-DG处理MDA-MB-231和MCF-7细胞48小时。通过将培养基中的葡萄糖浓度逐渐降低至0 g/L来进行葡萄糖饥饿处理，在此期间细胞在含有胎牛血清的条件下维持一周。使用Affymetrix Human Clariom S微阵列进行表达谱分析。从转录组分析控制台获得差异表达基因，并使用DAVID和R软件包进行富集。
我们的结果表明，MDA-MB-231细胞比MCF-7细胞对葡萄糖剥夺更敏感。在MDA-MB-231细胞的所有三种葡萄糖剥夺处理后均检测到内质网应激反应和细胞周期抑制，而在MCF-7细胞中仅在二甲双胍和葡萄糖饥饿条件下检测到。在MDA-MB-231细胞和经二甲双胍处理的MCF-7细胞的所有三种处理中均观察到凋亡诱导和DNA复制抑制。在MDA-MB-231细胞系和经二甲双胍处理的MCF-7细胞中，二甲双胍和葡萄糖饥饿处理后导致细胞对活性氧的反应上调和DNA修复机制受到抑制。在MDA-MB-231细胞中2-DG处理后以及在MCF-7细胞中二甲双胍处理后诱导了自噬。最后，仅在MDA-MB-231细胞的葡萄糖饥饿处理中观察到DNA甲基化受到抑制。
用于处理癌细胞并分析其表达数据的方法使我们的研究有别于其他研究。与2-DG和MET相比，葡萄糖饥饿对乳腺癌细胞的影响最大。联合使用二甲双胍和葡萄糖饥饿可抑制这两种细胞系，使其对传统化疗更敏感。
