ABSTRACT
Deciphering the crosstalk between RNA-binding proteins and corresponding RNAs will provide a better understanding of gastric cancer (GC) progression. The comprehensive bioinformatics study identified cytoplasmic polyadenylation element-binding protein 3 (CPEB3) might play a vital role in GC progression. Then we found CPEB3 was downregulated in GC and correlated with prognosis. In addition, CPEB3 suppressed GC cell proliferation, invasion and migration in vitro, as well as tumor growth and metastasis in vivo. Mechanistic study demonstrated CPEB3 interacted with 3'-UTR of ADAR1 mRNA through binding to CPEC nucleotide element, and then inhibited its translation by localizing it to processing bodies (P bodies), eventually leading to the suppression of ADAR1-mediated RNA editing. Microscale thermophoresis assay further revealed that the direct interaction between CPEB3 and GW182, the P-body's major component, was through the 440-698AA region of CPEB3 binding to the 403-860AA region of GW182. Finally, AAV9-CPEB3 was developed and administrated in mouse models to assess its potential value in gene therapy. We found AAV9-CPEB3 inhibited GC growth and metastasis. Besides, AAV9-CPEB3 induced hydropic degeneration in mouse liver, but did not cause kidney damage. These findings concluded that CPEB3 suppresses GC progression by inhibiting ADAR1-mediated RNA editing via localizing ADAR1 mRNA to P bodies.
Subject(s)
RNA Editing , Stomach Neoplasms , 3' Untranslated Regions/genetics , Adenosine Deaminase/genetics , Adenosine Deaminase/metabolism , Animals , Mice , Nucleotides , RNA Editing/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA-Binding Proteins/genetics , RNA-Binding Proteins/metabolism , Stomach Neoplasms/genetics , Stomach Neoplasms/pathologyABSTRACT
Tertiary lymphoid structures (TLS) are lymphoid aggregates in tumor tissues and their potential significance in clinical applications has not been fully elucidated in gastric cancer. We evaluated TLS and tumor-infiltrating immune cells using H&E and immunohistochemistry staining in the recruited patients with gastric cancer. The prognostic value of TLS was evaluated by Kaplan-Meier analysis and further validated using gene expression profiling. The alterations in gene mutation, copy number variance, and DNA methylation across the TLS signature subtypes were analyzed based on the Cancer Genome Atlas cohort. High TLS density was associated with improved overall survival and disease-free survival. A combination of TLS density and TNM stage obtained higher prognostic accuracy than the TNM stage alone. Tumors with high TLS density showed significantly higher infiltration of CD3+, CD8+, and CD20+ cells but lower infiltration of CD68+ cells. Transcriptomics analysis demonstrated that high TLS signature status was positively associated with the activation of inflammation-related and immune-related pathways. Multi-omics data showed a distinct landscape of somatic mutations, copy number variants, and DNA methylation across TLS signature subtypes. Our results indicated that TLS might link with enhanced immune responses, and represent an independent and beneficial predictor of resected gastric cancer. Multi-omics analysis further revealed key tumor-associated molecular alterations across TLS signature subtypes, which might help explore the potential mechanism of the interaction between TLS formation and cancer cells.
Subject(s)
Stomach Neoplasms , Tertiary Lymphoid Structures , Disease-Free Survival , Humans , Lymphocytes, Tumor-Infiltrating , Prognosis , Stomach Neoplasms/genetics , Stomach Neoplasms/pathology , Tertiary Lymphoid Structures/genetics , Tertiary Lymphoid Structures/pathology , Tumor MicroenvironmentABSTRACT
A novel direct method has been developed for determination of n-octanol-water partition coefficients by hollow-fiber membrane solvent microextraction (HFMSME) combined with high-performance liquid chromatography (HPLC). The compound of interest is dissolved in water with sonication and a hollow fiber containing octanol inside is placed in the sample solution to perform microextraction. After microextraction the concentrations in both the aqueous and n-octanol phases are analyzed by HPLC with UV detection. The method was evaluated with ten reference compounds and shown to be suitable for determination of the partition coefficients of organic compounds accurately, cheaply, simply, and quickly. Previously unknown n-octanol-water partition coefficients have been obtained for other compounds by use of the hollow-fiber membrane solvent-microextraction technique.
