Functional And Mechanistic Studies Of Long Non-coding RNA GAPLINC In Renal Cell Carcinomas

Renal cell carcinoma is the most common malignancy of the kidney,with over25% of patients with renal cancer presenting with locally advanced or metastatic disease at diagnosis and 20-40% of patients with localised primary tumours presenting with metastatic disease.Radiotherapy and chemotherapy are ineffective in patients with metastatic renal cell carcinoma and therefore this group is under-treated and has a poor prognosis.In the last decade,small molecule inhibitors,RNAtargeting strategies,immunomodulatory drugs and targeted therapies based on initiating/editing the immune system have offered hope for patients with metastatic kidney cancer,but mortality has not changed significantly and the treatment of metastatic kidney cancer remains a serious challenge.Long non-coding RNAs(Lnc RNAs)are RNAs with sequences longer than200 bp that are localised in the nucleus or cytoplasmic components of cells and are overwhelmingly untranslatable into proteins.lnc RNAs have been found to be widely involved in human diseases and are prominent in tumour initiation,promotion and progression.Researchers have found that lnc RNAs TUG1,MALAT1 and HOTAIR are closely associated with tumourigenesis and metastasis in kidney cancer progression.The CD44-positive regulator of gastric adenocarcinoma-associated intergenic long non-coding RNA(GAPLINC)is a newly identified lnc RNA that actively participates in a variety of tumourigenesis.however,the functional role and mechanism of GAPLINC in renal cell carcinogenesis has not been reported.We applied gene microarray technology to detect differentially expressed lnc RNAs in kidney cancer tissues and normal kidney tissues,and identified differentially expressed GAPLINC.we evaluated the effects of GAPLINC on kidney cancer in vitro and in vivo through cell proliferation,migration and angiogenesis assays.Mechanistically,we investigated the interaction between GAPLINC,mi R-135b-5p and CSF1 by RNA sequencing to detect changes in m RNA expression profiles following GAPLINC silencing and luciferase reporter assays,as well as by RNA-pull-down and RNA immunoprecipitation(RIP)assays to investigate the relationship between GAPLINC,ILF3 and VEGFA.We found that GAPLINC was significantly upregulated in kidney cancer tissues and cell lines and was associated with poor prognosis in kidney cancer patients.In vitro and in vivo,knockdown of the GAPLINC gene inhibited the growth of kidney cancer.Mechanistically,we found that GAPLINC promoted the proliferation and migration of kidney cancer by acting as a sponge for mi R-135b-5p,upregulating the expression of oncogene CSF1,and promoting angiogenesis in kidney cancer by binding ILF3 and stabilizing VEGFA m RNA.In conclusion,GAPLINC may be a new prognostic indicator and molecular therapeutic target for kidney cancer.