Mitotic kinase PBK/TOPK as a therapeutic target for adult T-cell leukemia/lymphoma
Mitotic kinase PBK/TOPK as a therapeutic target for adult T-cell leukemia/lymphoma
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作为成人 T 细胞白血病/淋巴瘤治疗靶点的有丝分裂激酶 PBK/TOPK
DOI：
10.3892/ijo.2018.4427
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发表时间：
2018-08-01
影响因子：
5.2
通讯作者：
Mori, Naoki
中科院分区：
文献类型：
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作者：
Ishikawa, Chie;Senba, Masachika;Mori, Naoki
成人 T 细胞白血病/淋巴瘤 (ATLL) 是一种涉及人类 T 细胞白血病病毒 1 型 (HTLV-1) 感染的 T 细胞的疾病，其特征是克隆性肿瘤增殖增加。 PDZ 结合激酶 (PBK) [也称为 T 淋巴细胞激活的杀伤细胞源蛋白激酶 (TOPK)] 是一种在增殖细胞中表达的丝氨酸/苏氨酸激酶，并在有丝分裂过程中被磷酸化。在本研究中，通过蛋白质印迹分析和RT-PCR检测PBK/TOPK的表达和磷酸化。我们发现 PBK/TOPK 在 HTLV-1 转化的 T 细胞系和 ATLL 衍生的 T 细胞系中上调并磷酸化。值得注意的是，磷酸化 PBK/TOPK 的 CDK1/cyclin B1 在这些细胞中过度表达。在共培养测定中，HTLV-1 感染上调外周血单核细胞 (PBMC) 中的 PBK/TOPK 表达。有效的 PBK/TOPK 抑制剂 HI-TOPK-032 和来自褐藻的岩藻依聚糖以剂量依赖性方式降低这些细胞系的增殖和活力。相比之下，HI-TOPK-032 对 PBMC 的影响不太明显。 HI-TOPK-032 治疗导致 G(1) 细胞周期停滞，并降低 CDK6 表达和 pRb 磷酸化，这是 G(1) 期进展的关键决定因素。此外，HI-TOPK-032 诱导细胞凋亡，形态学变化、聚 (ADP-核糖) 聚合酶裂解以及 caspase-3、-8 和 -9 激活以及 sub-G(1) 细胞群和 APO2.7 阳性细胞的增加证明了这一点。此外，HI-TOPK-032还抑制细胞凋亡抑制剂2（c-IAP2）、X连锁凋亡抑制剂（XIAP）、生存素和骨髓细胞白血病-1（Mcl-1）的表达，并诱导Bak和干扰素诱导的四肽重复蛋白（IFIT）1、2和3的表达。值得注意的是，该抑制剂的使用导致了细胞凋亡的抑制。 IB 激酶 (IKK)、IKK、IB、磷酸酶和张力蛋白同源物 (PTEN) 和 Akt 的磷酸化，以及 JunB 和 JunD 蛋白表达的降低，表明 PBK/TOPK 影响核因子 B、Akt 和激活蛋白 1 信号通路。在体内，施用 HI-TOPK-032 可抑制 ATLL 异种移植模型中的肿瘤生长。因此，总的来说，这项关于 PBK/TOPK 的鉴定和功能分析的研究表明，该激酶是 ATLL 治疗的一个有前途的分子靶点。
Adult T-cell leukemia/lymphoma (ATLL) is a disorder involving human T-cell leukemia virus type 1 (HTLV-1)-infected T-cells characterized by increased clonal neoplastic proliferation. PDZ-binding kinase (PBK) [also known as T-lymphokine-activated killer cell-originated protein kinase (TOPK)] is a serine/threonine kinase expressed in proliferative cells and is phosphorylated during mitosis. In this study, the expression and phosphorylation of PBK/TOPK were examined by western blot analysis and RT-PCR. We found that PBK/TOPK was upregulated and phosphory-lated in HTLV-1-transformed T-cell lines and ATLL-derived T-cell lines. Notably, CDK1/cyclin B1, which phosphorylates PBK/TOPK, was overexpressed in these cells. HTLV-1 infection upregulated PBK/TOPK expression in peripheral blood mononuclear cells (PBMCs) in co-culture assays. The potent PBK/TOPK inhibitors, HI-TOPK-032, and fucoidan from brown algae, decreased the proliferation and viability of these cell lines in a dose-dependent manner. By contrast, the effect of HI-TOPK-032 on PBMCs was less pronounced. Treatment with HI-TOPK-032 resulted in G(1) cell cycle arrest, and decreased CDK6 expression and pRb phosphorylation, which are critical determinants of progression through the G(1) phase. In addition, HI-TOPK-032 induced apoptosis, as evidenced by morphological changes, the cleavage of poly(ADP-ribose) polymerase with the activation of caspase-3, -8 and -9, and an increase in the sub-G(1) cell population and APO2.7-positive cells. Moreover, HI-TOPK-032 inhibited the expression of cellular inhibitor of apoptosis 2 (c-IAP2), X-linked inhibitor of apoptosis protein (XIAP), survivin and myeloid cell leukemia-1 (Mcl-1), and induced the expression of Bak and interferon-induced protein with tetratricopeptide repeats (IFIT)1, 2 and 3. It is noteworthy that the use of this inhibitor led to the inhibition of the phosphorylation of IB kinase (IKK), IKK, IB, phosphatase and tensin homolog (PTEN) and Akt, and to the decreased protein expression of JunB and JunD, suggesting that PBK/TOPK affects the nuclear factor-B, Akt and activator protein-1 signaling pathways. In vivo, the administration of HI-TOPK-032 suppressed tumor growth in an ATLL xenograft model. Thus, on the whole, this study on the identification and functional analysis of PBK/TOPK suggests that this kinase is a promising molecular target for ATLL treatment.