Central Laboratory, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310005, P.R. China.
The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310005, P.R. China.
Mol Med Rep. 2019 Sep;20(3):2159-2166. doi: 10.3892/mmr.2019.10465. Epub 2019 Jul 3.
Ribonucleotide reductase M2 (RRM2) is one of the two subunits that comprise ribonucleotide reductase (RR), the enzyme that catalyzes the conversion of ribonucleotide 5'‑diphosphates into 2'‑deoxyribonucleotides, which are required for DNA synthesis. RRM2 is a stress response factor important for the development of several tumors. However, its role in multiple myeloma (MM) remains to be fully elucidated. The present study aimed to investigate the role of RRM2 in MM. The expression of RRM2 in patients with MM was analyzed using the Oncomine database. The results demonstrated that RRM2 expression was higher in MM compared with healthy subjects. Reverse transcription‑quantitative polymerase chain reaction and western blot results revealed that RRM2 expression was decreased following transfection with a small interfering RNA targeting RRM2 into NCI‑H929 cells. RR activity and Cell Counting Kit‑8 assays demonstrated that RRM2 silencing reduced RR activity and inhibited cell proliferation. Annexin V‑propidium iodide staining indicated that the percentage of apoptotic NCI‑H929 cells was increased following RRM2 silencing compared with that in the control group. Increased phosphorylation of H2AX indicated that RRM2 silencing may activate the DNA‑damage response pathway in NCI‑H929 cells. Western blot analysis revealed that protein levels of the apoptosis‑associated factor Bcl‑2 were reduced, whereas Bax, cleaved caspase‑3 and cleaved poly(ADP‑ribose) polymerase 1 were upregulated following RRM2 silencing compared with the control group. In addition, the results demonstrated that RRM2 silencing may inhibit target gene expression in the Wnt/β‑catenin signaling pathway by increasing the phosphorylation of glucose synthase kinase 3β. These findings indicated that RRM2 may be involved in the proliferation and apoptosis of MM cells via the Wnt/β‑catenin signaling pathway, suggesting that RRM2 may represent a novel therapeutic target for MM.
核糖核苷酸还原酶 M2（RRM2）是组成核糖核苷酸还原酶（RR）的两个亚基之一，RR 酶催化核糖核苷酸 5'-二磷酸转化为 2'-脱氧核糖核苷酸，这是 DNA 合成所必需的。RRM2 是一种应激反应因子，对几种肿瘤的发展很重要。然而，其在多发性骨髓瘤（MM）中的作用仍有待充分阐明。本研究旨在探讨 RRM2 在 MM 中的作用。使用 Oncomine 数据库分析 MM 患者中 RRM2 的表达。结果表明，与健康受试者相比，MM 中 RRM2 的表达更高。逆转录-定量聚合酶链反应和 Western blot 结果显示，用靶向 RRM2 的小干扰 RNA 转染 NCI-H929 细胞后，RRM2 表达降低。RR 活性和细胞计数试剂盒-8 测定表明，RRM2 沉默降低了 RR 活性并抑制了细胞增殖。 Annexin V-碘化丙啶染色表明，与对照组相比，RRM2 沉默后 NCI-H929 细胞的凋亡率增加。H2AX 磷酸化增加表明 RRM2 沉默可能激活 NCI-H929 细胞中的 DNA 损伤反应途径。Western blot 分析显示，与对照组相比，RRM2 沉默后凋亡相关因子 Bcl-2 的蛋白水平降低，而 Bax、cleaved caspase-3 和 cleaved poly(ADP-ribose) polymerase 1 上调。此外，结果表明，RRM2 沉默可能通过增加葡萄糖合酶激酶 3β的磷酸化来抑制 Wnt/β-连环蛋白信号通路中的靶基因表达。这些发现表明，RRM2 可能通过 Wnt/β-连环蛋白信号通路参与 MM 细胞的增殖和凋亡，提示 RRM2 可能成为 MM 的一种新的治疗靶点。
