| Objective: The incidence of prostate cancer,the most common malignancy of male genitourinary system,has been ranked in the top three among all kinds of malignant tumors worldwide.Due to the changes of social economy,living environment and other factors,the incidence of prostate cancer has increased rapidly,and the subsequent mortality rate remains high.In addition,patients with advanced metastatic prostate cancer account for a large proportion in the newly diagnosed patients.The etiology of prostate cancer has not been fully elucidated and the treatment of advanced prostate cancer is very limited.Therefore,further exploration of the occurrence and development mechanism of prostate cancer at the molecular level,development of new biological markers for the early diagnosis and monitoring disease of prostate cancer,and new exploration of possible therapeutic targets of prostate cancer are attempted.It has been found that non-coding RNA is widely involved in all aspects of life,including growth,differentiation,development,immunity,etc.,and even plays an important regulatory role in tumor formation.There are various types of non-coding RNAs,among which long non-coding RNAs are widely distributed in the human genome.Although they do not encode proteins,they are widely involved in abnormal cellular biological processes,such as the development of malignant tumors,tumor energy metabolism,osteogenic differentiation of stem cells,and diseases related to the immune system.Molecular bait function of long non-coding RNAs has become a research hotspot in recent years.Molecular bait refers to the spongy function of long non-coding RNAs,also known as mimicry,that is,long non-coding RNAs can induce other RNAs or proteins to leave the original target,thus reducing its function.At present,a large number of long non-coding RNAs have been confirmed to be associated with the occurrence and development of prostate cancer.SNHG3 is a novel oncogenic long non-coding RNA,which is abnormally expressed in various tumors and can be used as a competitive endogenous RNA to promote malignant progression of various tumors.More and more research evidence indicates that lnc RNA SNHG3 plays a crucial role in the occurrence,development and prognosis of various malignant tumors,and it may be a valuable prognostic biomarker and therapeutic target in various malignant tumors.However,its mechanism of action in prostate cancer remains to be explored and completed.Methods: 1.Transcriptome data and clinicopathological data of 342 patients with prostate cancer and 42 patients without prostate cancer were obtained by The Cancer Genome Atlas database.R language software was used to compare the gene expression profiles of the normal group and the tumor group,and to analyze the correlation between the survival date of prostate cancer patients and the expression of SNHG3.The downstream genes of related genes were predicted by a series of databases.2.q RT-PCR and Western blot were used to detect the expression of related genes in prostate cancer cells and the expression of related genes after transfection of different plasmids in prostate cancer cells.3.Exam the distribution of SNHG3 in prostate cancer cells by FISH.4.By constructing plasmid,transformation,plasmid extraction and cell transfection,prostate cancer cells with down-regulated or up-regulated expression of related genes were constructed for subsequent experiments.5.CCK-8 assay,clonal formation assay and transwell assay were used to detect the proliferation,migration and invasion of cells.The cell apoptosis and cell cycle were detected by flow cytometry.6.Double luciferase reporter gene assay and RIP assay were used to prove that related genes could bind to each other.7.The decrease of proliferation ability of prostate cancer cells in methionine-deficient medium was detected by CCK-8 assay,so as to evaluate the methionine dependence of prostate cancer cells.8.The effect of down-regulated expression of SNHG3 on tumor proliferation in nude mice was investigated by tumor formation experiment in vivo,and the proportion of Ki-67 positive cells in tumor tissue of nude mice was detected by immunohistochemistry experiment.Nude mice with down-regulated expression of SNHG3 were fed in methionine-deficient condition,and methionine dependence of tumor tissue cells was evaluated by the degree of decline in end-stage tumor mass.Results: 1.The TCGA database indicated that SNHG3 was significantly overexpressed in prostate cancer patients,and the patients with relatively high expression of SNHG3 had poor prognosis.2.SNHG3 was highly expressed in prostate cancer tissues and cell lines(P < 0.05).The clinicopathological analysis of the patients suggested that SNHG3 could promote the disease progression of the patients.3.The expression of SNHG3 in prostate cancer cells was mainly distributed in the cytoplasm.Down-regulated or up-regulated expression of SNHG3 in prostate cancer cells were successfully constructed.Down-regulation of SNHG3 significantly inhibited cell proliferation,migration,invasion and cell cycle progression,and promoted cell apoptosis.Over-expression of SNHG3 significantly promoted cell proliferation,migration,invasion and cell cycle progression,and inhibited cell apoptosis.4.SNHG3 target gene miR-152-3p was predicted by the database,and the expression of the two genes was negatively correlated,the expression of miR-152-3p in the TCGA database was significantly lower in prostate cancer tissues(P < 0.05).5.The dual luciferase reporter gene assay and RNA immunoprecipitation assay verified that SNHG3 could target to miR-152-3p and negatively regulate its expression.MiR-152-3p was significantly lower expressed in prostate cancer tissues and cell lines by q RT-PCR assay(P < 0.05).6.SLC7A11,the target gene of miR-152-3p,the expression of the two was negatively correlated.In the TCGA database,SLC7A11 was significantly high expressed in prostate cancer patients(P < 0.05).7.Dual luciferase reporter gene assay verified that miR-152-3p could target to SLC7A11 and negatively regulate its expression.SLC7A11 was significantly over expressed in prostate cancer tissues and cell lines by q RT-PCR assay(P < 0.05).8.The rescue experiment confirmed that lnc RNA SNHG3/miR-152-3p/SLC7A11 gene axis can regulate the malignant progression of prostate cancer cells.9.GSEA enrichment analysis predicted that the functional enrichment of gene regulatory axis in prostate cancer cells affected cysteine and methionine metabolism.The dependence of prostate cancer cells on methionine was significantly increased after sulfasalazine treatment(P < 0.05).It was further verified that down-regulated expression of SNHG3 could significantly improve the dependence of prostate cancer cells on methionine,resulting in a significant decline in the proliferation ability of prostate cancer cells in the absence of methionine,and the silencing of miR-152-3p or over-expressed of SLC7A11 could save the effects of down-regulated expression of SNHG3(P < 0.05).10.The end-stage tumor mass and volume of nude mice with down-regulated expression of SNHG3 were decreased in tumor formation experiments(P < 0.05).Down-regulated expression of SNHG3 can improve methionine dependence of prostate cancer cells in nude mice,resulting in a significant decrease in tumor formation ability of prostate cancer cells in the absence of methionine(P < 0.05).Conclusion: 1.The highly expressed SNHG3 is significantly correlated with disease progression of patients.2.SNHG3 can promote the proliferation,migration and invasion,inhibit cell apoptosis,and affect cell cycle in prostate cancer cells.3.The expression of SNHG3 is mainly distributed in the cytoplasm of prostate cancer cells,and it regulates the expression of SLC7A11 through competitive binding of miR-152-3p,thus exerting its biological function.4.Lnc RNA SNHG3/miR-152-3p/SLC7A11 gene axis can regulate the proliferation,colony formation,migration and invasion of prostate cancer cells,as well as cell apoptosis,cell cycle and methionine dependence.5.Down-regulated expression of SNHG3 can significantly inhibit tumor growth and proliferation,and improve methionine dependence of prostate cancer cells in nude mice. |
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