| Background:It has been reported that Long Non-coding RNA(LncRNA)plays an important role in tumorigenesis.In previous studies,we screned LncRNA expression in gastric cancer through microarray,and LncRNA-DRD5P2 was significantly down-regulated in gastric cancer tissus and closely related to gastric cancer metastasis.However,the role and mechanism of LncRNA-DRD5P2 in the progression of gastric cancer remains unclear.The first part of this topic will explore the role and molecular mechanism of DRD5P2 in inhibiting gastric cancer metastasis in vitro and in vivo.Oncostatin M Receptor(OSMR)is a member of the interleukin 6(IL-6)receptor family and is a type II receptor for Oncostatin M.OSMR is abnormally expressed in many tumors and is closely related to poor prognosis.The second part of this topic is to explore the clinical significance and mechanism of OSM-OSMR in the progression of gastric cancer.Methods:The first part:RT-PCR and Fluorescence in situ hybridization(FISH)were used to detect the expression of DRD5P2 in gastric cancer tissue samples and cell lines.The impact of DRD5P2 on gastric cancer migration and invasion were tested by transwell migration and migration assay.after overexpression or knockout of DRD5P2 expression in gastric cancer cell lines.Epithelial-mesenchymal transition(EMT)markers and activation of ERK signaling pathway in gastric cancer cells was detected by Western blot.The effect of DRD5P2 on the peritoneal dissemination of gastric cancer cells was examined by intraperitoneal implantation in nude mice.Binding of DRD5P2 and Rock2 was verified using RNA pulldown followed by mass spectrometry(MS)and RNA immunoprecipitation(RIP).Proteins binding to Rock2 were analyzed using Co-IP.The second part:Western blot and RT-PCR were used to detect the expression of OSMR in gastric cancer and gastric cancer cells.The OSMR small hairpin RNA plasmid was constructed and the cell lines stably expressing OSMR shRNA were selected.The effect of OSM-OSMR on gastric cancer cell proliferation,migration and metastasis were tested.EMT marker and STAT3,FAK and SRC signaling status in gastric cancer cells was detected by Western blot.The effects of OSM-OSMR on peritoneal dissemination were examined by intraperitoneal implantation in nude mice.The transcriptional regulation of SP1 on OSMR was verified by the dual luciferase reporter gene assay and CHIP assay.Results:The first part:DRD5P2 is lowly expressed in gastric cancer tissues and cell lines.DRD5P2 expression is closely related to the prognosis of gastric cancer.DRD5P2 inhibits invasion and migration of gastric cancer cells in vitro.DRD5P2 can cause mesenchymal-epithelial transformation(MET)of gastric cancer cells.DRD5P2 inhibits the activation of the ERK signaling pathway.DRD5P2 binds to Rock2 and promotes its degradation.Rock2 binds and activates Ezrin,which transmits the activation signal to the HRAS/ERK axis.The second part:OSMR is lowly expressed in gastric cancer tissues and gastric cancer cells,and its expression level is negatively correlated with survival time.OSM-OSMR promotes proliferation,invasion and migration of gastric cancer cells.OSM-OSMR can cause EMT in gastric cancer cells.OSM-OSMR activates STAT3,FAK and SRC signaling.The expression of OSMR is regulated by SP1.Conclusion:The first part:DRD5P2 is lowly expressed in gastric cancer.DRD5P2 inhibits the activation of the Ezrin/HRAS/ERK axis by promoting the ubiquitination of Rock2 and inhibits the metastasis of gastric cancer.The second part:OSMR is transcriptionally regulated by SP1.OSM-OSMR promotes the proliferation and metastasis of gastric cancer through the STAT3/FAK/SRC. |
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