Orthopaedics Department, The First Affiliated Hospital of Henan University, Kaifeng, Henan, China.
Department of Hematology and Oncology, No. 988 Hospital of Joint Logistic Support Force of the Chinese People's Liberation Army, Zhengzhou, Henan Province, China.
Life Sci. 2020 Dec 1;262:118506. doi: 10.1016/j.lfs.2020.118506. Epub 2020 Oct 5.
Bortezomib (BTZ) is described as the first-line agent for multiple myeloma (MM) chemotherapy, but the emergence of BTZ resistance usually results in the failure of chemotherapy in MM. Circular RNA (circRNA) itchy E3 ubiquitin protein ligase (circITCH) is a novel identified circRNA that plays a vital role in the development of human cancers. However, the role of circITCH in the development of BTZ resistance in MM remains elusive.
The expression of circITCH, miR-615-3p, and protein kinase C, delta (PRKCD) was detected with quantitative reverse transcription PCR and western blot. The effects of circITCH on the sensitivity of MM cells to BTZ were assessed using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, flow cytometry, and xenograft tumor assay. The interaction of circITCH, microRNA-615-3p, and PRKCD was explored using luciferase reporter assay and RNA immunoprecipitation assay.
circITCH was downregulated in MM bone marrow specimens and cell lines, as well as BTZ-resistant MM cells. Reduced expression of circITCH was indicative of poor prognosis in MM patients. Upregulation of circITCH enhanced the sensitivity of BTZ-resistant MM cells to BTZ in vitro and in vivo. Furthermore, circITCH was identified as a sponge for miR-615-3p, and PRKCD is confirmed as a direct target of miR-615-3p. Besides, circITCH overexpression enhanced the sensitivity of MM cells to BTZ through miR-615-3p/PRKCD axis.
circITCH overexpression enhanced the sensitivity of MM cells to BTZ through miR-615-3p/PRKCD axis, providing a novel potential target for combating BTZ resistance in patients with MM.
硼替佐米（BTZ）被描述为多发性骨髓瘤（MM）化疗的一线药物，但 BTZ 耐药的出现通常导致 MM 化疗失败。环状 RNA（circRNA）痒 E3 泛素蛋白连接酶（circITCH）是一种新发现的环状 RNA，在人类癌症的发展中起着至关重要的作用。然而，circITCH 在 MM 中 BTZ 耐药发展中的作用仍不清楚。
采用定量逆转录 PCR 和 Western blot 检测 circITCH、miR-615-3p 和蛋白激酶 C，δ（PRKCD）的表达。通过 3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐（MTT）比色法、流式细胞术和异种移植瘤实验评估 circITCH 对 MM 细胞对 BTZ 敏感性的影响。通过荧光素酶报告基因实验和 RNA 免疫沉淀实验探索 circITCH、miR-615-3p 和 PRKCD 的相互作用。
circITCH 在 MM 骨髓标本和细胞系以及 BTZ 耐药 MM 细胞中下调。circITCH 表达降低提示 MM 患者预后不良。circITCH 的上调增强了 BTZ 耐药 MM 细胞在体外和体内对 BTZ 的敏感性。此外，circITCH 被鉴定为 miR-615-3p 的海绵，PRKCD 被确认为 miR-615-3p 的直接靶标。此外，circITCH 过表达通过 miR-615-3p/PRKCD 轴增强 MM 细胞对 BTZ 的敏感性。
circITCH 通过 miR-615-3p/PRKCD 轴增强 MM 细胞对 BTZ 的敏感性，为克服 MM 患者 BTZ 耐药提供了新的潜在靶点。
