Li Guang, Zheng Yan-Hua, Xu Li, Feng Juan, Tang Hai-Long, Luo Cheng, Song Yan-Ping, Chen Xie-Qun
Department of Hematology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
State Key Laboratory of Drug Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Science, Shanghai, China.
Ther Adv Hematol. 2020 Jun 8;11:2040620720932686. doi: 10.1177/2040620720932686. eCollection 2020.
Multiple myeloma (MM) is the second most common hematological neoplasm. Wide administration of bortezomib significantly improves the survival of MM patients compared with conventional chemotherapy. Bromodomain-containing protein 4 (BRD4) inhibitors also have been demonstrated to retard cell proliferation and induce cellular apoptosis in various cancers. However, it is unclear whether the BRD4 inhibitor nitroxoline plus bortezomib has a synergistic anti-tumor effect on MM.
Cell viability was determined 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle and cell apoptosis were assessed flow cytometry. Protein expression levels were determined western blotting. The expression of apoptosis-related proteins in xenograft tissue were detected by means of immunohistochemistry.
Treatment with nitroxoline or bortezomib suppressed cell proliferation, and caused G0/G1 phase arrest and apoptosis in H929 and RPMI8226 cells. Furthermore, nitroxoline intensified the retardation of cell proliferation, as well as further enhanced the G0/G1 phase arrest and apoptosis induced by bortezomib in H929 and RPMI8226 cells. The western blot analysis revealed that nitroxoline or bortezomib treatment markedly diminished the levels of Bcl-2 and cyclin D1, and increased the levels of p21, Bax, cleaved PARP and cleaved caspase-3. Combination of these two agents was observed to result in further marked changes on these levels compared with nitroxoline or bortezomib treatment alone. What is more, in the xenograft tumor model, combinative treatment markedly inhibited tumor growth compared with the single drug treatment.
Combination of bortezomib with nitroxoline has a synergistic anti-tumor activity in MM cells and may be a novel treatment method for MM.
多发性骨髓瘤（MM）是第二常见的血液系统肿瘤。与传统化疗相比，硼替佐米的广泛应用显著提高了MM患者的生存率。含溴结构域蛋白4（BRD4）抑制剂也已被证明可在多种癌症中抑制细胞增殖并诱导细胞凋亡。然而，尚不清楚BRD4抑制剂硝氧喹啉联合硼替佐米对MM是否具有协同抗肿瘤作用。
采用3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（MTT）法测定细胞活力。通过流式细胞术评估细胞周期和细胞凋亡。采用蛋白质印迹法测定蛋白质表达水平。通过免疫组织化学检测异种移植组织中凋亡相关蛋白的表达。
硝氧喹啉或硼替佐米处理可抑制H929和RPMI8226细胞的增殖，并导致G0/G1期阻滞和细胞凋亡。此外，硝氧喹啉增强了细胞增殖的抑制作用，并进一步增强了硼替佐米诱导的H929和RPMI8226细胞的G0/G1期阻滞和细胞凋亡。蛋白质印迹分析显示，硝氧喹啉或硼替佐米处理显著降低了Bcl-2和细胞周期蛋白D1的水平，并增加了p21、Bax、裂解的PARP和裂解的半胱天冬酶-3的水平。与单独使用硝氧喹啉或硼替佐米处理相比，观察到这两种药物联合使用可导致这些水平发生更显著的变化。此外，在异种移植肿瘤模型中，联合治疗与单药治疗相比显著抑制了肿瘤生长。
硼替佐米与硝氧喹啉联合在MM细胞中具有协同抗肿瘤活性，可能是MM的一种新治疗方法。
