CBP/p300 Regulates IGF2BP2 And Promotes Proliferation And Pharmacogenomic Changes In Pancreatic Cancer

Pancreatic cancer(PC)is a digestive malignancy with highly poor prognosis,and pancreatic ductal adenocarcinoma(PDAC)accounts for 95%of its pathology.Thus,the most critical work in the diagnosis and treatment of PD AC is to explore the pathogenesis and optimize the patient’s individual management or risk stratification according to the clinical and molecular data.Epigenetics is the study of omics that affects gene characteristics by regulating transcription or translation without changing the sequence of nucleotides.Among them,N6-methyladenosine(m6A)is the most widely studied epigenetic modification in eukaryotes.This modification is mediated by multiple reader genes and plays a vital regulatory part in cell differentiation and metabolism of tumor.Therefore,it is necessary for us to screen out the specific modification pattern of m6A reader gene,dig into its function and mechanism,and explore its pharmacogenomic characteristics,so as to shed light on the precise treatment of PD AC.(1)Aim:We aimed to explore the landscape of m6A reader gene at the multi-omics level,to screen out the key genes that changed the modification pattern of m6A reader gene,to find out its regulatory mechanism and influence on the malignant biological behavior in PD AC,and to identify the sensitive drug targets and small molecule compounds for high-risk patients with PD AC so as to achieve individualized treatment for PD AC patients.(2)Methods:First,based on the TCGA-PAAD,PACA-AU,PACACA,GSE28735 and GSE62452 cohorts,this study explored the specific changes of m6A reader genes at a multi-omic level,the correlation analysis between m6A reader genes and prognosis of PDAC patients was also implemented which combined with clinical data;Second,we detected the correlation between specific expression patterns of m6A reader genes in PDAC and enrichment pathways,tumor immunity and clinical molecular subtypes via unsupervised consensus clustering algorithm.Then,these specific patterns were quantified by PCA algorithm and the m6A reader hub gene was confirmed.Third,we analyzed the upstream regulatory mechanism of the hub gene using ChIP-seq and ATAC-seq databases,and the expression of the upstream target in PDAC cell lines was verified by immunohistochemical staining,and the malignant biological behavior of the target gene in PDAC was confirmed by CCK-8 and soft agar assay.Also,the effect of this target on IGF2BP2 expression was further verified.Finally,machine learning algorithms such as Bootstrapping and RSF were utilized to quantify the expression patterns of this hub gene and we also constructed a prognostic model for PDAC patients.Then,pharmacogenomic databases such as CTRP,PRISM and CMap were adopted to screen out sensitive drug targets and small molecule compounds for high-risk patients with PDAC in an all-round and multi-angle manner.(3)Results:First of all,we mapped the landscape of m6A reader genes in PDAC,and we found that the m6A reader gene,especially the IGF2BP family,had specific alterations and were significantly associated with poor prognosis,according to the clinical data;Second,we found two specific expression patterns of m6A reader genes in PDAC,and determined that the expression pattern with poor prognosis was associated with Th2 cell polarization and malignant clinical molecular subtype.At the same time,we identified IGF2BP2 as the hub gene which led to the specific expression pattern of m6A reader genes by PCA contribution analysis.Third,we preliminarily determined that CBP/p300 may cooperate with transcription cofactor BRD4 to catalyze the modification of histone H3K27ac in the promoter region of IGF2BP2,resulting in the increased transcriptional activity of IGF2BP2.Otherwise,we verified through experiments that the expression of CBP/p300 were up-regulated in PDAC tissues.CBP could significantly promote the proliferation of PDAC cells and up-regulate the expression of IGF2BP2.Next,we found that abnormally high expression of IGF2BP2 was associated with enrichment and activation of cell cycle pathways and tumor-related pathways in PDAC patients.A clinical prognosis scoring system containing 13 genes(FNDC3B,L1CAM,PLXNA1,HMGA2,FAM110B,FAM83A,COX7A1,PMAIP1,KIF20B,SPDL1,SNCG,TGM2 and MUC16)was also constructed and this model was validated to have robust predictive efficiency.Finally,we identified seven therapeutic targets(FOXM1,PRC1,CCNB1,SLC16A3,CCNA2,GGCX,and AURKA)and two drugs(Tipifarnib and Vemurafenib)for high-risk PD AC patients.(4)Conclusion:In this study,we found that IGF2BP2 is the hub gene which served as a significant factor leading to specific modification pattern of m6A reader genes in PDAC.Mechanically,CBP/p300 may be the upstream target of IGF2BP2,which promotes the development of PD AC by regulating the proliferation of PDAC cells.In addition,we further explored potential therapeutic targets and small molecule compounds in high-risk patients with PDAC.