Valipour Behnaz, Davari Sahar, Farahzadi Raheleh, Pourrasol Shahram, Mehran Niloofar, Dizaji Asl Khadijeh, Altaha Seyed Mansour, Hojjati Zahra, Nozad Charoudeh Hojjatollah
Department of Anatomical Sciences, Sarab Faculty of Medical Sciences, Sarab, Iran.
Department of Anatomical Sciences, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
Cell Biochem Funct. 2023 Dec;41(8):1477-1487. doi: 10.1002/cbf.3888. Epub 2023 Nov 28.
Acute myeloid leukemia (AML) is a highly lethal hematological malignancy in adults and children. Abnormal proliferation of leukemia stem cells (LSC) with CD34 and CD38 phenotypes are the main clinical features of AML. Patients with AML face drug resistance and treatment failure due to a default in stem and progenitor cells. Therefore, defining LSC properties is necessary for targeting leukemia-initiating cells. Mitochondrial mass and activity increase in AML initiating cells compared with normal stem cells. This idea has offered the inhibition of the mitochondrial translation machinery to reduce the number of leukemia-initiating cells in patients with AML Tigecycline is an FDA-approved microbial antibiotic that inhibits oxidative phosphorylation in mitochondria, resulting in the suppression of leukemia cell proliferation with little toxicity to normal cells. Thus, the present study was conducted to evaluate whether LSC is influenced by mitochondrial inhibition. We measured the IC50 of tigecycline in KG-1a AML cell lines. KG-1a AML cell lines were separated into CD34 and CD34 cells by MACS. In the following, these cells were treated with 20 µM (IC50) tigecycline. The expression of Annexin/PI, Caspase 3, apoptotic genes (BCL2, BCLX, BAX, BAD, and P53) and proteins (P53, BAX, BCL2 and Caspase 9) was evaluated in CD34 , CD34 and KG-1a AML cells. In addition, the telomere length and expression of hTERT were evaluated in this study. The results indicated that BCl2 (gene and protein) and BCLX gene dramatically decreased. In addition, BAD, BAX, and P53 gene and protein expression significantly increased in CD34 AML cells compared to CD34 AML cells. The results also suggested that tigecycline induced intrinsic (Cleaved-caspase 9/Pro-Caspase 9 ratio) and p53-mediated apoptosis. Furthermore, hTERT gene expression and telomere length decreased in the tigecycline-treated groups. Taken together, our findings indicate that inhibition of mitochondrial activity with tigecycline can induce apoptosis in cancer stem cells and can be used as a novel method for cancer therapy.
急性髓系白血病（AML）是一种在成人和儿童中具有高度致死性的血液系统恶性肿瘤。具有CD34和CD38表型的白血病干细胞（LSC）异常增殖是AML的主要临床特征。由于干细胞和祖细胞缺陷，AML患者面临耐药性和治疗失败的问题。因此，定义LSC特性对于靶向白血病起始细胞是必要的。与正常干细胞相比，AML起始细胞中的线粒体质量和活性增加。这一观点提出抑制线粒体翻译机制以减少AML患者白血病起始细胞的数量。替加环素是一种经美国食品药品监督管理局（FDA）批准的微生物抗生素，它抑制线粒体中的氧化磷酸化，导致白血病细胞增殖受到抑制，而对正常细胞毒性很小。因此，本研究旨在评估LSC是否受到线粒体抑制的影响。我们测量了替加环素在KG-1a AML细胞系中的半数抑制浓度（IC50）。通过磁珠细胞分选法（MACS）将KG-1a AML细胞系分为CD34⁺和CD34⁻细胞。接下来，用20μM（IC50）的替加环素处理这些细胞。评估了CD34⁺、CD34⁻和KG-1a AML细胞中膜联蛋白/碘化丙啶（Annexin/PI）、半胱天冬酶3、凋亡基因（BCL2、BCL-X、BAX、BAD和P53）和蛋白（P53、BAX、BCL2和半胱天冬酶9）的表达。此外，本研究还评估了端粒长度和人端粒酶逆转录酶（hTERT）的表达。结果表明，BCl2（基因和蛋白）和BCL-X基因显著下降。此外，与CD34⁻ AML细胞相比，CD34⁺ AML细胞中BAD、BAX和P53基因及蛋白表达显著增加。结果还表明，替加环素诱导内在性（裂解的半胱天冬酶9/原半胱天冬酶9比值）和p53介导的凋亡。此外，在替加环素处理组中，hTERT基因表达和端粒长度下降。综上所述，我们的研究结果表明，用替加环素抑制线粒体活性可诱导癌症干细胞凋亡，并可作为一种新的癌症治疗方法。
