ZBE1-AS1 Acts As A CeRNA To Facilitate Gastric Cancer Progression

Background: Due to its aggressive nature gastric cancer(GC)still causes the third largest number of cancer-associated deaths worldwide.Metastasis and recurrence are attributed to poor prognosis and stable mortality in GC patients.Notably,among the metastatic sites,peritoneal metastasis(PM)is the most untreatable condition with a poor prognosis and quality of life.Furthermore,epithelial mesenchymal transition(EMT)plays a key role in the metastasis of epithelium-derived carcinomas.During EMT,tumor cells acquire the characteristics of mesenchymal cells,which are easy to detach from primary tumors,degrade extracellular matrix,infiltrate into micro vessels and lymphatics,and cause dissemination around the body,and eventually lead to distant organ metastasis,or tumor cells directly penetrate the whole gastric wall,and implant into peritoneal cavity to cause peritoneal metastasis(PM).Therefore,to further explore the intrinsic mechanism of EMT and peritoneal metastasis in gastric cancer is of profound significance for formulating reasonable treatment strategies for gastric cancer and improving the quality of life and survival of patients with peritoneal metastasis of gastric cancer.Long noncoding RNAs(Lnc RNAs)are a non-protein coding group of transcripts that are over 200 nucleotides in size and exert crucial roles in transcriptional and post-transcriptional regulation,as well as chromatin modification.Due to the amazing regulatory ability in multiple tumor types,lnc RNAs are attracting increasing levels of attention.As a critical regulator,previous studies evidenced that lnc RNAs can influence invasion,EMT and metastasis in multiple tumor types.Micro RNAs(mi RNAs),another form of noncoding RNA,are 19–25 nucleotides in length.They can inhibit translation of m RNAs or degrade m RNA transcripts by binding to their 3'UTRs.Thus,mi RNAs can control gene expression at a posttranscriptional level thereby influencing the occurrence,progression and metastasis of multiple types of tumors.Current studies have suggested that GC cell EMT and metastasis can be modulated by mi RNAs.Recently,some studies suggested that lnc RNAs engage in crosstalk with m RNAs and act as competing endogenous RNAs(ce RNAs)by sequestering shared mi RNAs and lnc RNAs,m RNAs and mi RNAs communicate with each other and form competitive endogenous networks,which could be of profound significance to tumor mechanism investigation.Lnc RNA ZEB1 antisense 1(ZEB1-AS1)is transcribed from a shared bi-directional promoter of the zinc finger E-box binding homeobox 1 gene(ZEB1).Several studies have documented that ZEB1-AS1 can aggravate malignant behaviors of cancer cells through mi RNA-mediated mechanisms.However,it is still uncertain whether ZEB1-AS1 can interact with mi RNAs to form a ce RNA network in GC.ZEB1-AS1 has been found to promote tumor EMT and metastasis in GC,colorectal cancer,and hepatocellular carcinoma.However,the underlying mechanisms by which ZEB1-AS1 enables EMT and PM in GC remains to be discovered.Objective: Our study aimed to investigate how ZEB1-AS1 acts as a ce RNA to promote the progression of GC,especially initiate EMT and elicit PM events in GC.Methods: Mi RNAs interacting with ZEB1-AS1 were screened for and selected by bioinformatics analysis.Overexpression or repression of ZEB1-AS1 was performed to determine whether it could regulate the selected mi RNAs.Luciferase reporter assays were utilized to confirm the putative mi R-149-3p and mi R-937 binding sites in ZEB1-AS1 and examine whether the Yin Yang 1 transcription factor(YY1)can bind to the promoter of ZEB1-AS1.Statistical analysis determined the clinical significance of ZEB1-AS1 in relation to mi R-149-3p.Lastly,in-vitro and in-vivo assays were performed to identify how ZEB1-AS1 impacts cell proliferation,migration,invasion,EMT and PM in GC.Results: Bioinformatics analysis inferred that ZEB1-AS1 interacts with mi R-149,-204,-610 and-937.Supported by a luciferase reporter assay,gain-or loss-of function assays suggested that ZEB1-AS1 negatively regulates mi R-149-3p,-204-5p,-610 and-937 in GC cells as a ce RNA.Data analyses indicated that ZEB1-AS1 and mi R-149-3p can serve as valuable indicator for GC prognosis and diagnosis.Functional assays supported the theory that mi R-149-3p hinders GC proliferation,migration and invasion,whereas its overexpression abrogates the corresponding effects induced by ZEB1-AS1.In-vitro and in-vivo assays illustrated that knockdown of YY1 elicits repression of ZEB1-AS1,which induces mi R-937 expression,thus inhibiting EMT and hindering PM events in GC.Overexpression of ZEB1-AS1 abrogates the effects induced by knockdown of YY1,initiating EMT and eliciting PM events.Dissection of the molecular mechanisms involved indicated that ZEB1-AS1 can regulate GC proliferation,migration and invasion,partly via a ZEB1-AS1/mi R-149-3p axis and a novel YY1/ZEB1-AS1/mi R-937 axis exerts a vital regulatory role in GC EMT and PM.Conclusion: ZEB1-AS1 and mi R-149-3p can serves as promising biomarkers for GC prognosis and early diagnosis.ZEB1-AS1 can interact with specific mi RNAs to form a mi RNA-mediated ce RNA network and,partly through a ZEB1-AS1/mi R-149-3p axis,promote GC progress.A novel YY1/ZEB1-AS1/mi R-937 axis plays a vital regulatory role in GC EMT and PM.