Department of Oncology, Liaocheng Cancer Prevention and Treatment Hospital, Liaocheng, China.
Department of Pathology, Liaocheng Cancer Prevention and Treatment Hospital, Liaocheng, China.
Cancer Biother Radiopharm. 2020 Dec;35(10):741-752. doi: 10.1089/cbr.2019.3342. Epub 2020 May 14.
Chemoresistance greatly hinders the treatment of gastric cancer (GC). Long noncoding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) has been corroborated to be involved in chemoresistance in diverse cancers, including GC. The authors' aim was to investigate the underlying molecular mechanism of PVT1 in cisplatin (DPP) resistance in GC. Quantitative real-time polymerase chain reaction was conducted to detect the expression levels of PVT1, microRNA (miR)-3619-5p, and transducin beta like 1 x-linked receptor 1 (TBL1XR1) in DDP-resistant GC tissues and cells. 3-(4, 5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry assay were used to check cell viability, half inhibition concentration (IC), and apoptosis, respectively. The abilities of cell migration and invasion were evaluated by transwell assay. The protein levels of drug resistance-related proteins permeability glycoprotein (P-gp), glutathione s-transferase pi (GST-π), multidrug resistance-associated protein, and TBL1XR1 in samples were measured by Western blot. A xenograft tumor model was established to investigate the biological function of PVT1 . The starBase site was utilized to predict binding sites between miR-3619-5p and PVT1 or TBL1XR1, and the dual-luciferase reporter assay was performed to verify the interaction. The levels of PVT1 and TBL1XR1 were significantly upregulated in DPP-resistant GC tissues and cells, while miR-3619-5p was notably declined. Knockdown of PVT1 enhanced DPP sensitivity of DPP-resistant GC cells. Also, knockdown of PVT1 enhanced the sensitivity of DPP-resistant GC cells to DPP and inhibited tumor growth . Meanwhile, PVT1 silencing decreased the expression of drug-resistant proteins. Moreover, PVT1 interacted with miR-3619-5p, and TBL1XR1 was a target of miR-3619-5p. Further studies indicated that downregulation of miR-3619-5p transposed PVT1 silencing- or TBL1XR1 silencing-mediated effects on viability, apoptosis, migration, and invasion of DPP-resistant GC cells. PVT1 silencing attenuated the DPP resistance in GC by downregulating TBL1XR1 via sponging miR-3619-5p.
化学耐药性极大地阻碍了胃癌（GC）的治疗。长链非编码 RNA（lncRNA）浆细胞瘤变异易位 1（PVT1）已被证实参与了包括 GC 在内的多种癌症的化学耐药性。作者的目的是研究 PVT1 在 GC 顺铂（DPP）耐药中的潜在分子机制。 实时定量聚合酶链反应检测 DPP 耐药 GC 组织和细胞中 PVT1、微小 RNA（miR）-3619-5p 和转导素β样 1x 连锁受体 1（TBL1XR1）的表达水平。3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（MTT）法和流式细胞术分别用于检测细胞活力、半抑制浓度（IC）和凋亡。Transwell 测定法评估细胞迁移和侵袭能力。Western blot 法测定样品中耐药相关蛋白多药耐药相关蛋白、谷胱甘肽 S-转移酶 π（GST-π）、多药耐药相关蛋白和 TBL1XR1 的蛋白水平。利用星库网站预测 miR-3619-5p 与 PVT1 或 TBL1XR1 之间的结合位点，并通过双荧光素酶报告基因实验验证相互作用。建立异种移植肿瘤模型研究 PVT1 的生物学功能。 结果显示，DPP 耐药 GC 组织和细胞中 PVT1 和 TBL1XR1 水平显著上调，而 miR-3619-5p 水平显著下调。敲低 PVT1 增强了 DPP 耐药 GC 细胞对 DPP 的敏感性。此外，敲低 PVT1 可抑制 DPP 耐药 GC 细胞的生长。同时，PVT1 沉默降低了耐药蛋白的表达。此外，PVT1 与 miR-3619-5p 相互作用，TBL1XR1 是 miR-3619-5p 的靶基因。进一步研究表明，下调 miR-3619-5p 可逆转 PVT1 沉默或 TBL1XR1 沉默对 DPP 耐药 GC 细胞活力、凋亡、迁移和侵袭的影响。PVT1 沉默通过海绵 miR-3619-5p 下调 TBL1XR1 来减弱 GC 中的 DPP 耐药性。
