Abstract
Background: Gastric Cancer (GC) is one of the leading causes of cancer-related deaths and mortality. Long non-coding RNAs (lncRNAs) such as SNHG12 play important roles in the pathogenesis and progression of cancers. However, the role and significanve of SNHG12 in the metastasis of GC has not yet been thoroughly investigated.Methods: The SNHG12 expression pattern was detected in GC tissue samples from our faculty and cell lines using quantitative reverse transcription PCR. In vivo and in vitro gain and loss assays were conducted to observe the effects of SNHG12 regulation on GC cell metastasis potential. The underlying mechanisms of SNHG12 regulation on EMT and metastatic potential of GC cells were further determined by quantitative reverse transcription PCR, western blotting, dual luciferase reporter assays, co-immunoprecipitation, immunoprecipitation, RIP assays, TOPFlash/FOPFlash reporter assays and Ch-IP assays.Results: SNHG12 was upregulated in GC tissues and cell lines. The expression levels of SNHG12 in GC samples was significantly related to tumor invasion depth, TNM staging and lymph node metastasis, and was associated with poorer DFS and OS in the GC patients. SNHG12 was significantly highly expressed in peritoneal metastatic tissues from GC patients and mice subjects, suggesting a possible role of SNHG12 in peritoneal carcinomatosis from GC. Further in vivo and in vitro gain and loss assays indicated that SNHG12 promoted GC metastasis and EMT. Based on hypothetical bioinformatic analysis findings, our mechanistic analyses revealed that miR-218-5p was a direct target of SNHG12 and suggested that both SNHG12 and miR-218-5p could collectively regulate YWHAZ, forming the SNHG12/ miR-218-5p/YWHAZ axis, hereby decreasing the ubiquitination of β-catenin, thus activating the β-catenin signaling pathway and facilitating metastasis and EMT. Further analysis also revealed that the transcription factor YY1 could negatively modulate SNHG12 transcription.Conclusions: Our findings demonstrate that SNHG12 is be a potential prognostic marker and therapeutic target for GC. Negatively modulated by transcription factor YYI, SNHG12 promotes GC metastasis and EMT by regulating the miR-218-5p/YWHAZ axis and hence activating the β-catenin signaling pathway. Furthermore, we discovered high SNHG12 expression could be related to peritoneal carcinomatosis from GC but this requires further validation.
A functional analysis of the CREB signaling pathway using HaloCHIP-chip and high throughput reporter assays