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Tumor Discovery                                        PTMAP5–hsa-miR-22-3p–KIF2C axis in HCC development



            form of primary liver cancer.  Despite significant   upstream regulatory processes involving pseudogenes
                                        1
            advancements in liver cancer treatment over the past   and lncRNAs. The established PTMAP5–hsa-miR-22-3p–
            few years, the 5-year survival rate for patients remains   KIF2C competing endogenous RNA (ceRNA) subnetwork
            comparatively low. Persistent infections with hepatitis   may contribute to a comprehensive understanding of
            B virus (HBV) or hepatitis C virus (HCV), along with   HCC pathogenesis and could provide potential diagnostic
            risk factors such as alcoholism and diabetes mellitus, are   markers or therapeutic targets for the disease.
            identified  as  key  contributors  to  liver  cancer  incidence.
                                                          2
            Preventive measures, including the prevention of HBV and   2. Materials and methods
            HCV transmission, hepatitis B vaccination, treatment of   2.1. Prediction of upstream miRNAs
            chronic liver disease, and antiviral therapies, have proven             11
            effective in reducing the occurrence of HCC.  At present,   The miRTarBase dataset  provides information on
                                                3
            alpha-fetoprotein levels and ultrasonography results are   miRNA-mRNA targeting connections (microRNA-target
            the most commonly used diagnostic tools for liver cancer.    interactions), corroborated by experimental findings. In
                                                          4
            However, a majority of individuals with liver cancer are   this study, we used miRTarBase (https://mirtarbase.cuhk.
            diagnosed at advanced stages when detected, resulting in   edu.cn/) to predict upstream miRNAs for key genes. Our
            limited treatment options and poor prognoses. Therefore,   analysis revealed a significant negative correlation between
            early diagnosis is critical for improving survival rates, and   hsa-miR-22-3p and KIFC2 in HCC, suggesting a potential
            research on specific biomarkers, especially novel ones   regulatory pathway associated with HCC progression. The
            (such as miRNAs), holds great promise.             expression levels of KIF2C mRNA across various healthy
                                                               and cancerous human tissues were assessed using GEPIA. 12
              RNA molecules are broadly classified into two types:
            those  that  encode proteins  and  are  directly involved in   2.2. Co-expression analysis of KIF2C
            protein synthesis, known as messenger RNAs (mRNAs),   Co-expression  analysis  was  performed  utilizing
            and those that do not, referred to as non-coding RNAs   computational tools, specifically UALCAN.  and GEPIA.
                                                                                                  13
            (ncRNAs). Long non-coding RNAs (lncRNAs) constitute   This  rigorous  methodology  enabled  us  to  extract  and
            approximately 80% of ncRNAs and are regulated by a   identify the top 100 co-expressed genes from each
            diverse array of transcription factors.  Pseudogenes, which   platform. By intersecting these gene sets, we identified 37
                                         5
            possess highly homologous DNA sequences to functional   genes that were co-expressed with KIF2C and common to
            genes, have lost their original protein-coding ability.    both databases.
                                                          6
            LncRNAs can lead to transcriptional silencing or activation
            within the genome by recruiting epigenetic modifiers of   2.3. Kyoto encyclopedia of genes and genomes
            DNA,  while pseudogenes can regulate the expression   (KEGG) pathway enrichment analysis of
                7
            of their parental genes by binding to shared miRNAs.    differentially expressed miRNAs
                                                          8
            The involvement of pseudogenes and lncRNAs in cancer   Biochemical reaction pathways in cells often rely on
            development and advancement has become a focal point   the activity of differentially expressed proteins. KEGG
            of recent research in the field.                   pathway enrichment analysis of these genes provides
              In  this  study, we  followed  the  methods  described  in   valuable insights into the biological processes and
            Meng et al.  to develop a network linked to the advancement   signaling pathways in which they may be involved. To
                    9
            of HCC through various bioinformatics studies. The initial   further interpret gene functions, we applied the statistical
            step of our investigation involved retrieving the GSE87630   tools available in DAVID  (https://david.ncifcrf.gov) for
                                                                                    14
            and GSE45267 datasets from the gene expression omnibus   functional annotations. Gene ontology (GO) and KEGG
                                 10
            (GEO) version 10 database.  We employed the GEO2R tool   pathway  enrichment  analyses  were  conducted  utilizing
            to conduct an in-depth analysis of differentially expressed   DAVID, helping us gain a deeper insight into these genes,
            genes (DEGs) within these datasets. Common DEGs    and identify signaling pathways notably enriched with
            between the datasets were identified using Venn diagram   DEGs.
            software, resulting in 346 DEGs, including 69 upregulated
            and 277 downregulated genes in HCC. Subsequently, we   2.4. Analysis using the StarBase and MiRNet
            conducted protein–protein interaction (PPI) analysis to   databases
            identify central hub genes within this cohort of 346 genes.   We employed StarBase  to analyze miRNAs in relation to
                                                                                 15
            Following expression correlation and survival analysis,   gene expression and their interactions with pseudogenes
            hsa-miR-22-3p was identified as the miRNA most likely   or lncRNAs. In our quest to unravel intricate regulatory
            to bind to KIF2C. Further, investigation explored potential   networks, we applied a stringent threshold for identifying


            Volume 3 Issue 3 (2024)                         2                                 doi: 10.36922/td.2846
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