ABSTRACT
JAK2/STAT3/MYC axis is dysregulated in nearly 70 % of human cancers, but targeting this pathway therapeutically remains a big challenge in cancer therapy. In this study, genes associated with JAK2, STAT3, and MYC were analyzed, and potential target genes were selected. Leucine-rich PPR motif-containing protein (LRPPRC) whose function and regulation are not fully understood, emerged as one of top 3 genes in terms of RNA epigenetic modification. Here, we demonstrate LRPPRC may be an independent prognostic indicator besides JAK2, STAT3, and MYC. Mechanistically, LRPPRC impairs N6-methyladenosine (m6A) modification of JAK2, STAT3, and MYC to facilitate nuclear mRNA export and expression. Meanwhile, excess LRPPRC act as a scaffold protein binding to JAK2 and STAT3 to enhance stability of JAK2-STAT3 complex, thereby facilitating JAK2/STAT3/MYC axis activation to promote esophageal squamous cell carcinoma (ESCC) progression. Furthermore, 5,7,4'-trimethoxyflavone was verified to bind to LRPPRC, STAT3, and CDK1, dissociating LRPPRC-JAK2-STAT3 and JAK2-STAT3-CDK1 interaction, leading to impaired tumorigenesis in 4-Nitroquinoline N-oxide induced ESCC mouse models and suppressed tumor growth in ESCC patient derived xenograft mouse models. In summary, this study suggests regulation of m6A modification by LRPPRC, and identifies a novel triplex target compound, suggesting that targeting LRPPRC-mediated JAK2/STAT3/MYC axis may overcome JAK2/STAT3/MYC dependent tumor therapeutic dilemma.
Subject(s)
Esophageal Neoplasms , Esophageal Squamous Cell Carcinoma , Janus Kinase 2 , STAT3 Transcription Factor , Humans , Esophageal Squamous Cell Carcinoma/drug therapy , Esophageal Squamous Cell Carcinoma/metabolism , Esophageal Squamous Cell Carcinoma/pathology , Esophageal Squamous Cell Carcinoma/genetics , STAT3 Transcription Factor/metabolism , Animals , Janus Kinase 2/metabolism , Mice , Esophageal Neoplasms/metabolism , Esophageal Neoplasms/drug therapy , Esophageal Neoplasms/pathology , Esophageal Neoplasms/genetics , Cell Line, Tumor , Gene Expression Regulation, Neoplastic/drug effects , Cell Proliferation/drug effects , Disease Progression , Adenosine/analogs & derivatives , Adenosine/pharmacology , Adenosine/metabolism , Adenosine/chemistry , Flavones/pharmacology , Flavones/chemistry , CDC2 Protein Kinase/metabolism , CDC2 Protein Kinase/genetics , Signal Transduction/drug effects , Proto-Oncogene Proteins c-myc/metabolism , Proto-Oncogene Proteins c-myc/genetics , Female , Male , Flavonoids/pharmacology , Flavonoids/chemistry , Xenograft Model Antitumor Assays , Neoplasm Proteins/metabolism , Neoplasm Proteins/geneticsABSTRACT
BACKGROUND: Glutamyl-prolyl-tRNA synthetase (EPRS/GluRS) is primarily part of the multi-synthetase complex that may play a key role in cancer development. However, the biological function, molecular mechanism, and inhibitor of EPRS have not been investigated in gastric cancer (GC). METHODS: Immunohistochemistry was performed to detect the expression of EPRS in human gastric tumor tissues. Knocking down of EPRS, cell-derived xenograft mouse model, and patient-derived xenograft mouse model was used to identify the biological function of EPRS. Immunoprecipitation was applied to elucidate the interaction between EPRS and SCYL2. Computer docking model and multiple in vitro and in vivo experiments were conducted to discover EPRS inhibitors. RESULTS: Here, we report that EPRS is frequently overexpressed in GC tissues compared to that adjacent controls and its overexpression predicts poor prognosis in GC patients. Functionally, high expression of EPRS positively co-relates with GC development both in vitro and in vivo. Mechanistically, EPRS directly binds with SCYL2 to enhance the activation of WNT/GSK-3ß/ß-catenin signaling pathway and the accumulation of ß-catenin in the nuclear, leading to GC cell proliferation and tumor growth. Moreover, we identified that xanthoangelol (XA) and 4-hydroxyderricin (4-HD) can directly bind to EPRS to block WNT/GSK-3ß/ß-catenin signaling pathway. More importantly, XA and 4-HD restrain gastric cancer patient-derived xenograft tumor growth and Helicobacter pylori combined with alcohol-induced atrophic gastritis and gastric tumorigenesis. CONCLUSION: These findings unveil a promising strategy for GC prevention and therapy by targeting EPRS-mediated WNT/GSK-3ß/ß-catenin cascades. Moreover, XA and 4-HD may be effective reagents used for GC prevention and therapy.