Xia Bing, Guo Qing, Zhao Wei-peng, Guo Shan-qi, Tian Chen, Zhang Yi-zhuo
Department of Hematology, Cancer Institute & Hospital, Tianjin Medical University, Tianjin Key Laboratory of Cancer Prevention & Therapy, Tianjin 300060, China.
Zhonghua Yi Xue Za Zhi. 2013 Jun 11;93(22):1746-9.
To explore the role of c-Myc in mesenchymal stromal cell-mediated drug resistance and elucidate the molecular mechanism of acute myeloid leukemia (AML) from the version of tumor microenvironment.
AML cell lines U937 and KG1a were co-cultured with mesenchymal stromal cells (MSC) from bone marrow of healthy donors between January to March 2012. The AML cell lines plated alone was cultured as controls. Apoptosis induced by mitoxantrone was measured by flow cytometry and Annexin V/PI double and 4'-6-diamidino-2-phenylindole (DAPI) staining. And c-Myc protein was detected by Western blot under both culturing conditions. After a pre-treatment of c-Myc inhibitor 10058-F4, the apoptosis of AML cell was also evaluated.
Apoptosis of AML cells (U937 and KG1a) significantly decreased during co-culturing with MSC (9.88% ± 1.53% vs 42.83% ± 2.03%, P = 0.004;20.60% ± 2.87% vs 42.53% ± 5.29%, P = 0.030). Drug resistance was implicated. The co-culturing of AML cells with MSC significantly induced an up-regulation of c-Myc. The inhibition of c-Myc with 10058-F4 could induce apoptosis of AML cells. After an addition of 10058-F4 into the co-culture system, the apoptotic rate of KG1a cells significantly increased from 23.87% ± 1.55% to 57.23% ± 3.88% (P = 0.009). Similarly the apoptotic rates spiked from 16.07% ± 2.11% to 53.47% ± 4.08% in U937 cells (P = 0.004) to overcome the stromal cell-mediated drug resistance.
The co-culturing of AML cells and MSC induces an up-regulation of c-Myc protein so as to cause the emergence of chemoresistance. Therefore targeting c-Myc protein may provide a novel therapeutic strategy of AML.
探讨c-Myc在间充质基质细胞介导的耐药中的作用，并从肿瘤微环境角度阐明急性髓系白血病（AML）的分子机制。
2012年1月至3月，将AML细胞系U937和KG1a与健康供者骨髓间充质基质细胞（MSC）共培养。单独培养的AML细胞系作为对照。采用流式细胞术、Annexin V/PI双染及4',6-二脒基-2-苯基吲哚（DAPI）染色检测米托蒽醌诱导的细胞凋亡。在两种培养条件下，采用蛋白质免疫印迹法检测c-Myc蛋白。在使用c-Myc抑制剂10058-F4进行预处理后，也对AML细胞的凋亡情况进行了评估。
与MSC共培养期间，AML细胞（U937和KGla）的凋亡显著减少（9.88%±1.53%对42.83%±2.03%，P=0.004；20.60%±2.87%对42.53%±5.29%，P=0.030）。提示存在耐药性。AML细胞与MSC共培养显著诱导c-Myc上调。用10058-F4抑制c-Myc可诱导AML细胞凋亡。在共培养体系中加入10058-F4后，KG1a细胞的凋亡率从23.87%±1.55%显著增加至57.23%±3.88%（P=0.009）。同样，U937细胞的凋亡率从16.07%±2.11%飙升至53.47%±4.08%（P=0.004），以克服基质细胞介导的耐药性。
AML细胞与MSC共培养诱导c-Myc蛋白上调，从而导致化疗耐药的出现。因此，靶向c-Myc蛋白可能为AML提供一种新的治疗策略。
