Prognostic and Therapeutic Potential of The OIP5 Network in Papillary Renal Cell Carcinoma
Abstract Background: Papillary renal cell carcinoma (pRCC) is an aggressive but minor type of RCC compared to the main RCC type, clear cell RCC. The current understanding and management of pRCC remain poor. OIP5 possesses oncogenic functions; its contributions to pRCC remain unknown.Methods: OIP5 expression in pRCC at both the protein and mRNA levels was determined using tissue microarray and TCGA dataset. OIP5 was ectopically expressed in metastatic ACHN pRCC cells; xenografts were performed with gene expression profiled by RNA-seq. Differentially expressed genes (DEGs) were analyzed for prognostic potential and impact on pRCC. The effect of PLK1, an OIP5-related DEG, on pRCC tumor growth in vivo was examined.Results: OIP5 expression is upregulated in pRCC. The upregulation associates with pRCC adverse features (T1P<T2P<CIMP, Stage1+2<Stage 3<Stage 4, and N0<N1) and effectively stratifies the fatality risk. OIP5 promotes ACHN pRCC cell proliferation and xenograft formation. RNA-seq reveals network alterations related to immune regulation, metabolism, and hypoxia in ACHN OIP5 tumors compared to empty vector tumors. A set of DEGs was derived from ACHN OIP5 xenografts and primary pRCCs (n=282) contingent to OIP5 upregulation; both DEG sets share 66 overlap genes. Overlap66 effectively predicts overall survival (p<2e-16) and relapse (p<2e-16) possibilities. The prediction is associated with a good out-of-sample performance, supporting its clinical applications. High-risk tumors stratified by Overlap66 risk score possess an immune suppressive environment, evident by elevations in Treg cells and PD1 expression in CD8 T cells. Upregulation of PLK1 occurs in both xenografts and primary pRCC tumors with OIP5 elevations. PLK1 displays a synthetic lethality relationship with OIP5; PLK1 inhibitor BI2356 causes G2/M arrest in ACHN OIP5 cells in vitro and significantly inhibits the growth of xenografts formed by ACHN OIP5 cells in vivo. Conclusions: Our research reveals that OIP5 and its network possess robust prognostic and therapeutic potentials; the prognostic value of Overlap66 and the therapeutic potential of PLK1 inhibitors may pave the way for developing personalized medicine for pRCC management.