Shu Hao, Yuan Bin, Huang Yao, Wang Lei, He Bing, Sun Qi, Sun Luning
Department of Orthopedics, Sports Medicine Center, Affiliated Hospital of Nanjing University of Chinese Medicine, Hanzhong Road 115, Nanjing, 210029, China.
Department of Pathology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China.
J Orthop Surg Res. 2021 Jan 28;16(1):85. doi: 10.1186/s13018-021-02204-z.
Previous studies showed overexpression of ABCG2 in a variety of tumor tissues, which could potentially indicate the probability of chemotherapy resistance. This study aimed to reveal the role of ABCG2 in the development of chemotherapy resistance and the prognosis of osteosarcoma (OS).
Sixty-eight OS patients were included in this study. Tumor tissues were collected for each patient during surgery. DOX-resistant OS cell lines were induced by consecutive exposure of gradually increasing concentration of DOX to the parental cell lines. Lentivirus was used for the knockdown of ABCG2 in OS cells. Cells were treated with the gradient concentration of DOX, and the viability was assessed by CCK8 assay. Total RNA was isolated from the tumor tissues or tumor cells, and the expression of ABCG2 was analyzed by qPCR. The relationship between ABCG2 expression and clinicopathological characteristics of the patients was analyzed using Student's t test or the Chi-square test. The overall survival time was calculated by the Kaplan-Meier method and analyzed by the log-rank test. p < 0.05 was considered statistically significant.
DOX-resistant OS cells were successfully established through continuous exposure to DOX. Forty-eight hours after DOX exposure, the IC 50 value of DOX-resistant HOS cells and DOX-resistant U2OS was 3.5 μM and 3.25 μM, respectively. By contrast, those of the untreated HOS and U2OS cells were 1.15 μM and 0.93 μM, respectively (p < 0.01). The mRNA expression level of ABCG2 was significantly increased in DOX-resistant cell lines. The CCK-8 assay showed that the DOX-resistant HOS cells and DOX-resistant U2OS cells transfected with ShABCG2 were more sensitive to the DOX treatment than those transfected with ShCtrl. Analysis of gene expression in OS tissues showed remarkably higher expression of ABCG2 as compared with adjacent normal tissues (p < 0.01). Patients with high expression level of ABCG2 had obviously decreased overall survival time than the patients with normal expression (p < 0.01).
ABCG2 expression level was significantly associated with the resistance to chemotherapy and the overall survival of OS patients. ABCG2 may be a promising therapeutic target for OS patients.
既往研究表明ABCG2在多种肿瘤组织中过表达，这可能预示着化疗耐药的可能性。本研究旨在揭示ABCG2在骨肉瘤（OS）化疗耐药发生及预后中的作用。
本研究纳入68例OS患者。在手术过程中为每位患者采集肿瘤组织。通过将逐渐增加浓度的阿霉素连续暴露于亲本细胞系来诱导阿霉素耐药的OS细胞系。慢病毒用于敲低OS细胞中的ABCG2。用梯度浓度的阿霉素处理细胞，通过CCK8法评估细胞活力。从肿瘤组织或肿瘤细胞中分离总RNA，通过qPCR分析ABCG2的表达。使用Student's t检验或卡方检验分析ABCG2表达与患者临床病理特征之间的关系。通过Kaplan-Meier法计算总生存时间，并通过对数秩检验进行分析。p < 0.05被认为具有统计学意义。
通过持续暴露于阿霉素成功建立了阿霉素耐药的OS细胞。阿霉素暴露48小时后，阿霉素耐药的HOS细胞和阿霉素耐药的U2OS细胞的IC50值分别为3.5μM和3.25μM。相比之下，未处理的HOS和U2OS细胞的IC50值分别为1.15μM和0.93μM（p < 0.01）。ABCG2的mRNA表达水平在阿霉素耐药细胞系中显著升高。CCK-8分析表明，与转染ShCtrl的细胞相比，转染ShABCG2的阿霉素耐药HOS细胞和阿霉素耐药U2OS细胞对阿霉素治疗更敏感。OS组织中的基因表达分析显示，与相邻正常组织相比，ABCG2的表达明显更高（p < 0.01）。ABCG2高表达水平的患者总体生存时间明显低于正常表达的患者（p < 0.01）。
ABCG2表达水平与OS患者的化疗耐药性和总体生存显著相关。ABCG2可能是OS患者有前景的治疗靶点。
