Knockdown of long non-coding RNA HOTAIR inhibits cisplatin resistance of gastric cancer cells through inhibiting the PI3K/Akt and Wnt/β-catenin signaling pathways by up-regulating miR-34a.

HOX transcript antisense RNA (HOTAIR), a well-known long non-coding RNA (lncRNA), has been reported to be related to cisplatin (DDP) resistance in gastric cancers. However, the molecular mechanism of HOTAIR in DDP resistance of gastric cancer (GC) remains largely undefined. The aim of this study was to investigate the role and underlying mechanism of HOTAIR in regulating cisplatin resistance of GC. The results showed that HOTAIR was over-expressed in GC tissues and GC cell lines, while miR-34a was low-expressed. Luciferase reporter assay and RIP assay proved that HOTAIR directly bound to miR-34a. MiR-34a expression was significantly increased in si-HOTAIR-transfected cells. Anti-miR-34a reversed the effect of si-HOTAIR on the DDP resistance, apoptosis-related genes, PI3K/Akt and Wnt/β-catenin signaling pathways in DDP-resistant GC cells, indicating that the effects of HOTAIR are dependent on miR-34a. In addition, knockdown of HOTAIR enhanced DDP inhibitory effect on tumor growth in vivo. In conclusion, HOTAIR knockdown inhibited DDP resistance of gastric cancer cells by upregulating miR-34a. The effect of HOTAIR/miR-34a axis on GC cells may be involved in the PI3K/Akt and Wnt/β-catenin signaling pathways. The results indicated that HOTAIR might be a new potential target in GC therapy.

Cheng C ，Qin Y ，Zhi Q ，Wang J ，Qin C ... -  《-》

PCAT-1 contributes to cisplatin resistance in gastric cancer through miR-128/ZEB1 axis.

Increasing evidence suggests that dysregulation of long non-coding RNAs (lncRNAs) is implicated with chemoresistance in cancers. However, their function and molecular mechanisms in gastric cancer (GC) chemoresistance remain not well elucidated. In this study, we aimed to investigate the functional role and the underlying molecular mechanism of lncRNA prostate cancer-associated transcript 1 (PCAT-1) in cisplatin (DDP) resistance of GC. Our results revealed that PCAT-1 was up-regulated in DDP-resistant GC tissues and cells. GC patients with high PCAT-1 expression levels had a poor prognosis. Knockdown of PCAT-1 facilitated the sensitivity of DDP-resistant GC cells to DDP. Additionally, PCAT-1 functioned as a sponge of miR-128 in GC cells. Moreover, inhibition of miR-128 reversed the inductive effect of PCAT-1 knockdown on DDP sensitivity of GC cells. In addition, ZEB1 was identified as a target of miR-128, and overexpression of ZEB1 could block the inductive effect of PCAT-1 knockdown on DDP sensitivity of GC cells. Besides, PCAT-1 knockdown enhanced DDP sensitivity in tumors in vivo. In summary, PCAT-1 confers DDP resistance in GC cells through miR-128/ZEB1 axis, providing a promising therapeutic strategy for GC.

Guo Y ，Yue P ，Wang Y ，Chen G ，Li Y ... -  《-》

LncRNA SNHG6 knockdown inhibits cisplatin resistance and progression of gastric cancer through miR-1297/BCL-2 axis.

Cisplatin (DDP) resistance is a huge obstacle to gastric cancer (GC) treatment. Long non-coding RNAs (lncRNAs) have been manifested to exert pivotal functions in GC development. Herein, we aimed to explore the functional impact of lncRNA small nucleolar RNA host gene 6 (SNHG6) on DDP resistance and progression of GC. Quantitative real-time PCR (qRT-PCR) assay or Western blotting was performed to detect the expression of SNHG6, microRNA(miR)-1297, and epithelial-mesenchymal transition (EMT)-related factors and B-Cell Lymphoma 2 (Bcl-2) in DDP-resistant GC cells. Half inhibition concentration (IC50) to DDP, clonogenicity, apoptosis and invasion were examined via CCK-8 assay, colony formation assay, flow cytometry and Transwell assay, respectively. Target association between miR-1297 and SNHG6 or BCL-2 was demonstrated via dual-luciferase reporter assay or RIP assay. Xenograft models in nude mice were formed to investigate role of SNHG6 in vivo. We found that SNHG6 and BCL-2 were up-regulated, while miR-1297 expression was declined in GC tissues and DDP-resistant cells. Moreover, depletion of SNHG6 or gain of miR-1297 could repress DDP resistance, proliferation and metastasis of DDP-resistant cells, which was weakened by miR-1297 inhibition or BCL-2 overexpression. Besides, SNHG6 positively regulated BCL-2 expression by sponging miR-1297. Furthermore, SNHG6 knockdown repressed GC tumor growth in vivo. In a word, lncRNA SNHG6 knockdown had inhibitory effects on DDP resistance and progression of GC by sponging miR-1297, highlighting its potential in GC treatment.

Mei J ，Liu G ，Li R ，Xiao P ，Yang D ，Bai H ，Hao Y ... -  《-》

Downregulation of microRNA-4295 enhances cisplatin-induced gastric cancer cell apoptosis through the EGFR/PI3K/Akt signaling pathway by targeting LRIG1.

Yan R ，Li K ，Yuan DW ，Wang HN ，Zhang Y ，Dang CX ，Zhu K ... -  《-》

Knockdown of long non-coding RNA HOTAIR reverses cisplatin resistance of ovarian cancer cells through inhibiting miR-138-5p-regulated EZH2 and SIRT1.

Zhang Y ，Ai H ，Fan X ，Chen S ，Wang Y ，Liu L ... -  《-》