Haematology and Transfusion Medicine Centre - Hemocentro, University of Campinas, Campinas, 13083-878, Brazil.
Onco-Haematological Child Centre, Faculty of Medical Sciences, University of Campinas, Campinas, 13083-970, Brazil.
Sci Rep. 2021 Apr 27;11(1):9103. doi: 10.1038/s41598-021-88478-z.
(-)-Epigallocatechin-3-gallate (EGCG), the major active polyphenol extracted from green tea, has been shown to induce apoptosis and inhibit cell proliferation, cell invasion, angiogenesis and metastasis. Herein, we evaluated the in vivo effects of EGCG in acute myeloid leukaemia (AML) using an acute promyelocytic leukaemia (APL) experimental model (PML/RARα). Haematological analysis revealed that EGCG treatment reversed leucocytosis, anaemia and thrombocytopenia, and prolonged survival of PML/RARα mice. Notably, EGCG reduced leukaemia immature cells and promyelocytes in the bone marrow while increasing mature myeloid cells, possibly due to apoptosis increase and cell differentiation. The reduction of promyelocytes and neutrophils/monocytes increase detected in the peripheral blood, in addition to the increased percentage of bone marrow cells with aggregated promyelocytic leukaemia (PML) bodies staining and decreased expression of PML-RAR oncoprotein corroborates our results. In addition, EGCG increased expression of neutrophil differentiation markers such as CD11b, CD14, CD15 and CD66 in NB4 cells; and the combination of all-trans retinoic acid (ATRA) plus EGCG yield higher increase the expression of CD15 marker. These findings could be explained by a decrease of peptidyl-prolyl isomerase NIMA-interacting 1 (PIN1) expression and reactive oxygen species (ROS) increase. EGCG also decreased expression of substrate oncoproteins for PIN1 (including cyclin D1, NF-κB p65, c-MYC, and AKT) and 67 kDa laminin receptor (67LR) in the bone marrow cells. Moreover, EGCG showed inhibition of ROS production in NB4 cells in the presence of N-acetyl-L-cysteine (NAC), as well as a partial blockage of neutrophil differentiation and apoptosis, indicating that EGCG-activities involve/or are in response of oxidative stress. Furthermore, apoptosis of spleen cells was supported by increasing expression of BAD and BAX, parallel to BCL-2 and c-MYC decrease. The reduction of spleen weights of PML/RARα mice, as well as apoptosis induced by EGCG in NB4 cells in a dose-dependent manner confirms this assumption. Our results support further evaluation of EGCG in clinical trials for AML, since EGCG could represent a promising option for AML patient ineligible for current mainstay treatments.
（-）-表没食子儿茶素没食子酸酯（EGCG）是从绿茶中提取的主要活性多酚，已被证明可诱导细胞凋亡并抑制细胞增殖、细胞侵袭、血管生成和转移。在此，我们使用急性早幼粒细胞白血病（APL）实验模型（PML/RARα）评估了 EGCG 在急性髓系白血病（AML）中的体内作用。血液学分析显示，EGCG 治疗可逆转白细胞增多、贫血和血小板减少，并延长 PML/RARα 小鼠的存活时间。值得注意的是，EGCG 减少了骨髓中的白血病不成熟细胞和早幼粒细胞，同时增加了成熟的髓样细胞，这可能是由于细胞凋亡增加和细胞分化。在外周血中检测到早幼粒细胞和中性粒细胞/单核细胞的减少，以及骨髓细胞中聚集的早幼粒细胞白血病（PML）体染色百分比增加和 PML-RAR 致癌蛋白表达减少，这些都证实了我们的结果。此外，EGCG 增加了 NB4 细胞中中性粒细胞分化标志物如 CD11b、CD14、CD15 和 CD66 的表达；全反式维甲酸（ATRA）联合 EGCG 可使 CD15 标志物的表达增加更高。这些发现可以通过降低肽基脯氨酰异构酶 NIMA 相互作用 1（PIN1）的表达和增加活性氧（ROS）来解释。EGCG 还降低了骨髓细胞中 PIN1 的底物癌蛋白（包括细胞周期蛋白 D1、NF-κB p65、c-MYC 和 AKT）和 67kDa 层粘连蛋白受体（67LR）的表达。此外，在存在 N-乙酰-L-半胱氨酸（NAC）的情况下，EGCG 可抑制 NB4 细胞中 ROS 的产生，并部分阻断中性粒细胞分化和凋亡，表明 EGCG 的活性涉及或响应氧化应激。此外，通过增加 BAD 和 BAX 的表达来支持脾细胞的凋亡，同时伴随着 BCL-2 和 c-MYC 的减少。PML/RARα 小鼠脾脏重量的减少以及 EGCG 在 NB4 细胞中剂量依赖性诱导的凋亡证实了这一假设。我们的研究结果支持进一步评估 EGCG 在 AML 的临床试验中，因为 EGCG 可能是不适合当前主要治疗方法的 AML 患者的有前途的选择。
