Laboratory of Genetics and Molecular Hematology (LIM31), University of São Paulo Medical School (FMUSP), São Paulo, Brazil.
Proteomic Unit, Institute of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
J Proteomics. 2017 Jan 16;151:12-23. doi: 10.1016/j.jprot.2016.06.011. Epub 2016 Jun 23.
Chronic myeloid leukemia (CML) is a myeloproliferative disease with a characteristic BCR-ABL tyrosine kinase (TK) fusion protein. Despite the clinical efficacy accomplished by TKIs therapies, disease progression may affect patient response rate to these inhibitors due to a multitude of factors that could lead to development of a mechanism known as multidrug resistance (MDR). 7-Ketocholesterol (7KC) is an oxidized cholesterol derivative that has been extensively reported to cause cell death in a variety of cancer models. In this study, we showed the in vitro efficacy of 7KC against MDR leukemia cell line, Lucena. 7KC treatment induced reduction in cell viability, together with apoptosis-mediated cell death. Moreover, downregulation of MDR protein caused intracellular drug accumulation and 7KC co-incubation with either Daunorubicin or Vincristine reduced cell viability compared to the use of each drug alone. Additionally, quantitative label-free mass spectrometry-based protein quantification showed alteration of different molecular pathways involved in cell cycle arrest, induction of apoptosis and misfolded protein response. Conclusively, this study highlights the effect of 7KC as a sensitizing agent of multidrug resistance CML and elucidates its molecular mechanisms.
CML patients treated with tyrosine kinase inhibitors (TKIs) have showed a 5-year estimated overall survival of 89%, with cumulative complete cytogenetic response of 87%. However, development of drug resistance is a common feature of the disease progression. This study aimed at showing the effect of 7KC as a cytotoxic and sensitizing agent of multidrug resistance CML cell lines. The cellular and molecular basis of this compound were elucidated using a comprehensive strategy based on quantitative proteomic and cell biology assays. We showed that 7KC induced cell death and overcomes drug resistance in CML through mechanisms that go beyond the classical MDR1 pathways.
慢性髓细胞白血病（CML）是一种骨髓增生性疾病，具有特征性的 BCR-ABL 酪氨酸激酶（TK）融合蛋白。尽管 TKIs 治疗取得了临床疗效，但由于多种因素可能导致多药耐药（MDR）机制的发展，疾病进展可能会影响患者对这些抑制剂的反应率。7-酮胆固醇（7KC）是一种氧化胆固醇衍生物，已广泛报道可在多种癌症模型中引起细胞死亡。在这项研究中，我们展示了 7KC 对 MDR 白血病细胞系 Lucena 的体外疗效。7KC 处理诱导细胞活力降低，同时伴有凋亡介导的细胞死亡。此外，下调 MDR 蛋白导致细胞内药物积累，与单独使用每种药物相比，7KC 与柔红霉素或长春新碱共同孵育可降低细胞活力。此外，基于定量无标签质谱的蛋白质定量显示，不同分子途径发生改变，这些途径涉及细胞周期停滞、诱导细胞凋亡和错误折叠蛋白反应。总之，这项研究强调了 7KC 作为多药耐药 CML 敏化剂的作用，并阐明了其分子机制。
接受酪氨酸激酶抑制剂（TKIs）治疗的 CML 患者的 5 年总生存率估计为 89%，完全细胞遗传学缓解率为 87%。然而，耐药性的发展是疾病进展的一个常见特征。本研究旨在展示 7KC 作为多药耐药 CML 细胞系的细胞毒性和敏化剂的作用。使用基于定量蛋白质组学和细胞生物学测定的综合策略阐明了该化合物的细胞和分子基础。我们表明，7KC 通过超越经典 MDR1 途径的机制诱导 CML 细胞死亡并克服耐药性。
