Inhibition Of AURKB Confers Synthetic Lethality To Parp Inhibition In Skin Cutaneous Melanoma

Background and Objective:Despite significant advances,skin cutaneous melanoma(SKCM)is one of the most common life-threatening cancer worldwide,with a world estimated age-standardized incidence of 2.8-3.1 per 100,000.The prognosis of advanced melanoma is poor,and the five-year survival rate of patients with distant metastasis is less than 10%.Better therapies are still urgently needed,considering the high mortality for patients with advanced melanoma.Understanding the molecular mechanism of a particular disease is conducive to the development of new therapies as well as more accurate prognosis evaluation.Since the molecular mechanism of SKCM has not been fully explored at present,it is necessary to identify the key molecules and clarify their role in the progress of SKCM.Recent studies have suggested that competitive endogenous RNAs(ceRNAs)may play a role in the pathogenesis of malignant tumors.It shows great scientific research significance and clinical application value in finding potential therapeutic targets and biomarkers.Ce RNA reveals an interaction mechanism between non-coding RNAs(nc RNAs)and protein-coding RNAs,in particular,nc RNAs with micro RNAs(mi RNAs)response elements can remove the inhibition of mi RNAs on target genes by competitively binding to mi RNAs.Actually,pseudogenes can play a role as a ceRNA in carcinogenesis.The purpose of this study is to construct a ceRNA regulatory network of pseudogene-mi RNA-m RNA by bioinformatics methods,find the key target gene,and explore the biological function and potential mechanism of the target gene in SKCM.Methods:1.Bioinformatics databases were used to construct a pseudogene-mi RNA-m RNA ceRNA network.2.The si RNA of the pseudogene,mi RNA mimics and Western Blotting were used to verify the ceRNA network.3.MTS cell proliferation test,Western Blotting and flow cytometry were used to explore the role of the target gene in melanoma cell survival.4.Bioinformatics analysis,Western Blotting,drug combined effect test,flow cytometry,MTS cell proliferation test and a transplanted mouse tumor model were used to explore the mechanism of the target gene in SKCM.Results:1.In this study,seven up-regulated pseudogenes were identified in SKCM using The Cancer Genome Atlas(TCGA).Among them,only MTND4P12 was negatively correlated with the overall survival(OS)of SKCM patients.Hsa-let-7e-5p and hsa-mi R-1193 were identified as mi RNAs binding to MTND4P12 and 697 genes were identified as target genes binding to candidate mi RNAs.After protein-protein interaction analysis of the target genes,10 hub genes were identified,of which only the expression of Aurora kinase B(AURKB)binding to hsa-let-7e-5p was positively correlated with MTND4P12(P<0.0236)and negatively correlated with OS in SKCM patients(P<0.0047).The binding sites of the three were also predicted by bioinformatics methods.And the ceRNA regulatory network of MTND4P12,hsa-let-7e-5p and AURKB was constructed.2.The overexpression of hsa-let-7e-5p suppressed the AURKB expression.The suppressed expression of MTND4P12 down-regulated the AURKB expression.3.The inhibition of AURKB expression decreased the viability and increased apoptosis of melanoma cells.4.After the inhibition of AURKB,Gene Ontology(GO)analysis showed that genes related to DNA replication,DNA repair and inter-strand cross-linking repair were dominant.Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis showed that DNA replication,Fanconi anemia pathway and homologous recombination(HR)related genes were enriched,and Gene Set Enrichment Analysis(GSEA)analysis showed that regulation of double strand break repair via HR pathway related genes were enriched.The combination of AURKB inhibitor and poly-ADPribose polymerase inhibitors(PARPi)also led to more double-strand breaks,promoted melanoma cell apoptosis and inhibited SKCM tumor growth in C57BL/6mice as well as nude mice.Conclusions:In this study,the target gene AURKB in SKCM was found by the construction of a ceRNA network.It was found that gene knockout and chemical inhibition of AURKB could reduce the viability of melanoma cells and induce apoptosis.This study also found that inhibition of AURKB would affect the HR pathway.Therefore,the combined effect of AURKB inhibitor and PARPi was explored as well.And the synthetic lethal effect of the combination was confirmed by experiments in vitro and in vivo.In conclusion,the combination of AURKB inhibitor and PARPi has a synergistic effect and is expected to be a promising therapeutic method for SKCM.