Zhao Yan, Chen Yuetong, Wang Jing, Liu Liang
Department of Otolaryngology, Head and Neck Surgery, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China.
Tumor Institute, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China.
Oncol Lett. 2021 May;21(5):364. doi: 10.3892/ol.2021.12625. Epub 2021 Mar 10.
Drug resistance is one of the main factors limiting the efficacy of chemotherapy in patients with laryngeal cancer; thus, it is important to investigate the drug resistance of laryngeal cancer. In the present study, the mechanism of the regulation of drug resistance in laryngeal cancer cells by ATP-binding transporter G2 (ABCG2) that is present in the extracellular vesicles (EVs) released by drug-resistant cells was studied and . A cisplatin (CDDP)-resistant cell line (AMC-HN-8/CDDP) was established from AMC-HN-8 cells by continuous exposure to increasing concentrations of CDDP. The EVs extracted from the culture medium of AMC-HN-8/CDDP and AMC-HN-8 cells were termed EVs1 and EVs2, respectively. Following 48-h treatment of AMC-HN-8 cells with EVs1 or EVs2, the cells were designated as AMC-HN-8-EVs1 or AMC-HN-8-EVs2. Nude mice bearing AMC-HN-8-EVs1 and AMC-HN-8 cell-derived xenograft tumors were established to detect the effects of EVs on drug resistance. The resistance index of AMC-HN-8/CDDP cells to CDDP was 5.60, which was determined by the MTT assay. The mRNA and protein expression levels of ABCG2 in AMC-HN-8/CDDP cells and EVs1 were significantly higher compared with those in AMC-HN-8 cells and EVs2, respectively (P<0.01). The ABCG2 mRNA and protein levels, and the proliferation index of AMC-HN-8-EVs1 cells were significantly higher compared with those of AMC-HN-8-EVs2 and AMC-HN-8 cells (P<0.01), whereas the apoptotic rate was significantly lower (P<0.01). The mean volume of subcutaneous tumor xenografts in the test group (inoculated with AMC-HN-8-EVs1 cells and intraperitoneally injected with 3 mg/kg CDDP) was significantly higher compared with that in the control group (inoculated with AMC-HN-8 cells and intraperitoneally injected with 3 mg/kg CDDP) (P<0.01), whereas the apoptotic rate of tumor cells was significantly lower (P<0.01). The ABCG2 mRNA and the protein expression levels in the tumor cells of the test group were significantly higher compared with those in the blank (inoculated with AMC-HN-8 cells and was intraperitoneally injected with normal saline) and control groups (P<0.01). The high expression levels of ABCG2 in laryngeal carcinoma cells affected the drug resistance of the cells. The EVs released by drug-resistant cells upregulated the expression of ABCG2 and induced drug resistance in laryngeal carcinoma cells, which may be dependent on the ABCG2 gene carried by the EVs.
耐药性是限制喉癌患者化疗疗效的主要因素之一；因此，研究喉癌的耐药性具有重要意义。在本研究中，对耐药细胞释放的细胞外囊泡（EVs）中存在的ATP结合转运蛋白G2（ABCG2）调节喉癌细胞耐药性的机制进行了研究。通过持续暴露于浓度递增的顺铂（CDDP），从AMC-HN-8细胞建立了顺铂耐药细胞系（AMC-HN-8/CDDP）。从AMC-HN-8/CDDP和AMC-HN-8细胞的培养基中提取的EVs分别称为EVs1和EVs2。用EVs1或EVs2处理AMC-HN-8细胞48小时后，这些细胞分别命名为AMC-HN-8-EVs1或AMC-HN-8-EVs2。建立了携带AMC-HN-8-EVs1和AMC-HN-8细胞衍生异种移植瘤的裸鼠，以检测EVs对耐药性的影响。通过MTT法测定，AMC-HN-8/CDDP细胞对CDDP的耐药指数为5.60。与AMC-HN-8细胞和EVs2相比，AMC-HN-8/CDDP细胞和EVs1中ABCG2的mRNA和蛋白表达水平显著更高（P<0.01）。与AMC-HN-8-EVs2和AMC-HN-8细胞相比，AMC-HN-8-EVs1细胞的ABCG2 mRNA和蛋白水平以及增殖指数显著更高（P<0.01），而凋亡率显著更低（P<0.01）。试验组（接种AMC-HN-8-EVs1细胞并腹腔注射3mg/kg CDDP）皮下肿瘤异种移植的平均体积显著高于对照组（接种AMC-HN-8细胞并腹腔注射3mg/kg CDDP）（P<0.01），而肿瘤细胞的凋亡率显著更低（P<0.01）。与空白组（接种AMC-HN-8细胞并腹腔注射生理盐水）和对照组相比，试验组肿瘤细胞中ABCG2 mRNA和蛋白表达水平显著更高（P<0.01）。喉癌细胞中ABCG2的高表达水平影响了细胞的耐药性。耐药细胞释放的EVs上调了ABCG2的表达并诱导喉癌细胞产生耐药性，这可能依赖于EVs携带的ABCG2基因。
