Institute of Cancer Sciences, Faculty of Medical and Human Sciences, University of Manchester, and Manchester Academic Health Science Centre, Manchester, United Kingdom.
Department of Histopathology, Manchester Royal Infirmary, Central Manchester University Hospitals NHS Foundation Trust, Manchester, United Kingdom.
Exp Hematol. 2014 Mar;42(3):183-191.e5. doi: 10.1016/j.exphem.2013.11.006. Epub 2013 Nov 20.
In chronic myeloid leukemia (CML) cells from different stages of maturation may have differential expression of BCR-ABL at both messenger RNA (mRNA) and protein level. However, the significance of such differential expression to clinical disease behavior is unknown. Using the CML-derived, BCR-ABL expressing cell line, K562, distinct plastic-adherent (K562/Adh) and nonadherent (K562/NonAdh) subpopulations were established and then analyzed both as single cells and as bulk cell populations. BCR-ABL mRNA was upregulated in K562/Adh compared with K562/NonAdh cells in both single cell and bulk population analyses (p < 0.0001). Similarly, phosphorylation of BCR protein was upregulated in K562/Adh, compared with K562/NonAdh cells (63.42% vs. 23.1%; p = 0.007), and these two K562 subpopulations were found to express significantly different microRNA species. Furthermore, treatment with the BCR-ABL tyrosine kinase inhibitor, imatinib, reduced cell viability more rapidly in K562/NonAdh compared with K562/Adh cells (p < 0.005) both at single and bulk cell levels. This discovery of an adherent subpopulation of K562 cells with increased BCR-ABL mRNA, increased phosphorylated BCR protein expression, differential microRNA expression, and increased imatinib resistance suggests that a similar subpopulation of cells can also mediate clinical resistance to imatinib during treatment of patients with CML.
在不同成熟阶段的慢性髓性白血病 (CML) 细胞中，BCR-ABL 在信使 RNA (mRNA) 和蛋白水平上可能存在差异表达。然而，这种差异表达对临床疾病行为的意义尚不清楚。使用 CML 衍生的、表达 BCR-ABL 的细胞系 K562，建立了明显的贴壁（K562/Adh）和非贴壁（K562/NonAdh）亚群，然后分别对单细胞和细胞群体进行分析。在单细胞和细胞群体分析中，与 K562/NonAdh 细胞相比，K562/Adh 细胞中的 BCR-ABL mRNA 上调（p < 0.0001）。同样，与 K562/NonAdh 细胞相比，K562/Adh 细胞中 BCR 蛋白的磷酸化上调（63.42%比 23.1%；p = 0.007），并且这两种 K562 亚群被发现表达明显不同的 microRNA 种类。此外，用 BCR-ABL 酪氨酸激酶抑制剂伊马替尼治疗时，与 K562/Adh 细胞相比，K562/NonAdh 细胞的细胞活力更快降低（p < 0.005），无论是在单细胞还是细胞群体水平上。这一发现表明，K562 细胞的一个贴壁亚群具有增加的 BCR-ABL mRNA、增加的磷酸化 BCR 蛋白表达、差异 microRNA 表达和增加的伊马替尼耐药性，类似的细胞亚群也可以介导 CML 患者治疗期间对伊马替尼的临床耐药性。
