The First Affiliated Hospital of Zhejiang Chinese Medical University (Zhejiang Provincial Hospital of Chinese Medicine), Department of Hematology, Zhejiang, China
The Second Affiliated Hospital of Zhejiang Chinese Medical University, Department of Pharmacy, Zhejiang, China
Turk J Haematol. 2023 May 29;40(2):82-91. doi: 10.4274/tjh.galenos.2023.2022.0435. Epub 2023 Jan 31.
This study aimed to investigate the role and mechanism of circular RNA PVT1 (circPVT1) in patients with acute myeloid leukemia (AML).
The expression of circPVT1 in 23 patients with de novo AML (not acute promyelocytic leukemia, not APL) and cell lines were detected by RT-qPCR. Loss of function assays were carried out to explore the influence of silenced circPVT1 on the proliferation, migration, and apoptosis in the THP-1 cell line. CCK-8 assays, trans-well assays, and annexin V/PI staining assays were performed to assess proliferation, migration, and apoptosis, respectively.
CircPVT1 was highly expressed in AML patients and myeloid cell lines compared to healthy controls. Higher expression of circPVT1 was related to shorter overall survival (OS) and relapse-free survival (RFS) in AML patients. Cell viability and migration were inhibited and apoptosis was increased when circPVT1 was knocked down in THP-1 cells. Knockdown of circPVT1 resulted in marked suppression of c-Myc protein with no significant change in mRNA levels. We also found that circPVT1 knockdown markedly increased the phosphorylation of c-Myc Thr-58, which was responsible for c-Myc degradation. Silencing of c-Myc caused a significant decrease in CXCR4 mRNA and protein expression, whereas the overexpression of c-Myc caused the opposite result, suggesting that CXCR4 is a target molecule of c-Myc. Finally, we found that overexpression of c-Myc could partially reverse circPVT1 knockdown-induced anti-tumor effects on THP-1 cells in vitro.
Our findings showed that circPVT1 was highly expressed in AML patients and was related to shorter OS and RFS. CircPVT1 may exert an oncogenic effect in THP-1 cells by stabilizing c-Myc protein expression and downstream target CXCR4 expression. These data indicate that circPVT1 may be a promising therapeutic target for AML.
本研究旨在探讨环状 RNA PVT1（circPVT1）在急性髓系白血病（AML）患者中的作用和机制。
通过 RT-qPCR 检测 23 例初诊 AML 患者（非急性早幼粒细胞白血病，非 APL）和细胞系中 circPVT1 的表达。通过沉默 circPVT1 进行功能丧失实验，探讨其对 THP-1 细胞系增殖、迁移和凋亡的影响。CCK-8 法、Transwell 法和 Annexin V/PI 染色法分别评估细胞增殖、迁移和凋亡。
circPVT1 在 AML 患者和髓系细胞系中的表达明显高于健康对照组。circPVT1 表达水平升高与 AML 患者总生存（OS）和无复发生存（RFS）较短有关。在 THP-1 细胞中敲低 circPVT1 可抑制细胞活力和迁移，促进细胞凋亡。circPVT1 敲低导致 c-Myc 蛋白明显抑制，而 mRNA 水平无明显变化。我们还发现，circPVT1 敲低可显著增加 c-Myc Thr-58 的磷酸化，导致 c-Myc 降解。c-Myc 沉默导致 CXCR4 mRNA 和蛋白表达显著下调，而过表达 c-Myc 则导致相反的结果，提示 CXCR4 是 c-Myc 的靶分子。最后，我们发现，c-Myc 的过表达可以部分逆转 circPVT1 敲低对 THP-1 细胞的体外抗肿瘤作用。
我们的研究结果表明，circPVT1 在 AML 患者中高表达，并与较短的 OS 和 RFS 相关。circPVT1 可能通过稳定 c-Myc 蛋白表达及其下游靶标 CXCR4 表达在 THP-1 细胞中发挥致癌作用。这些数据表明，circPVT1 可能是 AML 的一种有前途的治疗靶点。
