Epigenetics in Human Health and Disease Program, Baker Heart and Diabetes Institute, 75 Commercial Road, Prahran, VIC, 3004, Australia.
Epigenomic Medicine Laboratory at prospED Training, Carlton, VIC, 3053, Australia.
Cell Mol Life Sci. 2023 Aug 14;80(9):248. doi: 10.1007/s00018-023-04905-6.
Human erythroleukemic K562 cells represent the prototypical cell culture model of chronic myeloid leukemia (CML). The cells are pseudo-triploid and positive for the Philadelphia chromosome. Therefore, K562 cells have been widely used for investigating the BCR/ABL1 oncogene and the tyrosine kinase inhibitor, imatinib-mesylate. Further, K562 cells overexpress transferrin receptors (TfR) and have been used as a model for targeting cytotoxic therapies, via receptor-mediated endocytosis. Here, we have characterized K562 cells focusing on the karyotype of cells in prolonged culture, regulation of expression of TfR in wildtype (WT) and doxorubicin-resistant cells, and responses to histone deacetylase inhibition (HDACi). Karyotype analysis indicates novel chromosomes and gene expression analysis suggests a shift of cultured K562 cells away from patient-derived leukemic cells. We confirm the high expression of TfR on K562 cells using immunofluorescence and cell-surface receptor binding radioassays. Importantly, high TfR expression is observed in patient-derived cells, and we highlight the persistent expression of TfR following doxorubicin acquired resistance. Epigenetic analysis indicates that permissive histone acetylation and methylation at the promoter region regulates the transcription of TfR in K562 cells. Finally, we show relatively high expression of HDAC enzymes in K562 cells and demonstrate the chemotoxic effects of HDACi, using the FDA-approved hydroxamic acid, vorinostat. Together with a description of morphology, infrared spectral analysis, and examination of metabolic properties, we provide a comprehensive characterization of K562 cells. Overall, K562 cell culture systems remain widely used for the investigation of novel therapeutics for CML, which is particularly important in cases of imatinib-mesylate resistance.
人红白血病 K562 细胞代表慢性髓系白血病（CML）的典型细胞培养模型。这些细胞是假三倍体，费城染色体阳性。因此，K562 细胞已被广泛用于研究 BCR/ABL1 癌基因和酪氨酸激酶抑制剂伊马替尼甲磺酸盐。此外，K562 细胞过度表达转铁蛋白受体（TfR），并已被用作通过受体介导的内吞作用靶向细胞毒性疗法的模型。在这里，我们对 K562 细胞进行了特征描述，重点是长期培养的细胞的核型、野生型（WT）和多柔比星耐药细胞中 TfR 的表达调控以及对组蛋白去乙酰化酶抑制剂（HDACi）的反应。核型分析表明存在新的染色体，基因表达分析表明培养的 K562 细胞偏离了患者来源的白血病细胞。我们使用免疫荧光和细胞表面受体结合放射分析证实了 K562 细胞上 TfR 的高表达。重要的是，在患者来源的细胞中观察到 TfR 的高表达，并且我们强调了在多柔比星获得耐药后 TfR 的持续表达。表观遗传学分析表明，启动子区域允许的组蛋白乙酰化和甲基化调节了 K562 细胞中 TfR 的转录。最后，我们显示 K562 细胞中 HDAC 酶的相对高表达，并使用经 FDA 批准的羟肟酸伏立诺他证明了 HDACi 的化学毒性作用。结合形态学描述、红外光谱分析和代谢特性检查，我们对 K562 细胞进行了全面表征。总的来说，K562 细胞培养系统仍然广泛用于研究 CML 的新型治疗方法，在伊马替尼甲磺酸盐耐药的情况下尤其重要。
