MEX3D is an oncogenic driver in prostate cancer

Ubiquitylation of RUNX3 by RNA-binding ubiquitin ligase MEX3C promotes tumorigenesis in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is the most common pathological type of lung cancer, but the early diagnosis rate is low. The RNA-binding ubiquitin ligase MEX3C promotes tumorigenesis in several cancers but its mechanism of action in LUAD is unclear. In this study, the biological activity of MEX3C was assessed in LUAD. MEX3C and RUNX3 mRNA levels in the tissues of LUAD patients were determined using reverse transcription‑quantitative PCR. The involvement of MEX3C in the growth and metastasis of LUAD cells was measured by EdU assay, CCK-8, colony formation, Transwell assay, TUNEL, and flow cytometry. Expression of apoptosis and epithelial-mesenchymal transition related proteins were determined using western blotting analysis. LUAD cells transfected with si-MEX3C were administered to mice subcutaneously to monitor tumor progression and metastasis. We found that MEX3C is strongly upregulated in LUAD tissue sections, and involved in proliferation and migration. A549 and H1299 cells had significantly higher levels of MEX3C expression compared to control HBE cells. Knockdown of MEX3C dramatically decreased cell proliferation, migration, and invasion, and accelerated apoptosis. Mechanistically, we demonstrate MEX3C induces ubiquitylation and degradation of tumor suppressor RUNX3. Moreover, RUNX3 transcriptionally represses Suv39H1, as revealed by RNA pull-down and chromatin immunoprecipitation assays. The in vivo mice model demonstrated that knockdown of MEX3C reduced LUAD growth and metastasis significantly. Collectively, we reveal a novel MEX3C-RUNX3-Suv39H1 signaling axis driving LUAD pathogenesis. Targeting MEX3C may represent a promising therapeutic strategy against LUAD.

Transcriptome signatures of host tissue infected with African swine fever virus reveal differential expression of associated oncogenes

African swine fever (ASF) has emerged as a threat to swine production worldwide. Evasion of host immunity by ASF virus (ASFV) is well understood. However, the role of ASFV in triggering oncogenesis is still unclear. In the present study, ASFV-infected kidney tissue samples were subjected to Illumina-based transcriptome analysis. A total of 2463 upregulated and 825 downregulated genes were differentially expressed (p < 0.05). A literature review revealed that the majority of the differentially expressed host genes were key molecules in signaling pathways involved in oncogenesis. Bioinformatic analysis indicated the activation of certain oncogenic KEGG pathways, including basal cell carcinoma, breast cancer, transcriptional deregulation in cancer, and hepatocellular carcinoma. Analysis of host-virus interactions revealed that the upregulated oncogenic RELA (p65 transcription factor) protein of Sus scrofa can interact with the A238L (hypothetical protein of unknown function) of ASFV. Differential expression of oncogenes was confirmed by qRT-PCR, using the H3 histone family 3A gene (H3F3A) as an internal control to confirm the RNA-Seq data. The levels of gene expression indicated by qRT-PCR matched closely to those determined through RNA-Seq. These findings open up new possibilities for investigation of the mechanisms underlying ASFV infection and offer insights into the dynamic interaction between viral infection and oncogenic processes. However, as these investigations were conducted on pigs that died from natural ASFV infection, the role of ASFV in oncogenesis still needs to be investigated in controlled experimental studies.

Identification of the circRNA-miRNA-mRNA Regulatory Network in Pterygium-Associated Conjunctival Epithelium

To investigate the regulatory mechanism of pterygium formation, we detected differentially expressed messenger RNAs (DE-mRNAs) and differentially expressed circular RNAs (DE-circRNAs) in pterygium-associated conjunctival epithelium (PCE) and normal conjunctival epithelium (NCE). Genome-wide mRNA and circRNA expression profiles of PCE and NCE were determined using high-throughput sequencing. Bioinformatics analyses, including Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, gene set enrichment analysis (GSEA), and protein-protein interaction (PPI) analysis, were conducted. The microRNAs (miRNAs) interacting with the hub DE-mRNAs and DE-circRNAs were predicted and verified using real-time quantitative PCR (RT-qPCR). The data showed that there were 536 DE-mRNAs (280 upregulated and 256 downregulated mRNAs) and 78 DE-circRNAs (20 upregulated and 58 downregulated circRNAs) in PCE. KEGG enrichment analysis indicated that the DE-mRNAs were mainly involved in the following biological processes: IL-17 signalling pathway, viral protein interaction with cytokine and cytokine receptor, cytokine-cytokine receptor interaction, ECM-receptor interaction, and focal adhesion. The GSEA results revealed that the epithelial mesenchymal transition (EMT) process was significantly enriched in upregulated mRNAs. The pterygium-associated circRNA-miRNA-mRNA network was established based on the top 10 DE-circRNAs, 4 validated miRNAs (upregulated miR-376a-5p and miR-208a-5p,downregulated miR-203a-3p and miR-200b-3p), and 31 DE-mRNAs. We found that miR-200b-3p, as a regulator of FN1, SDC2, and MEX3D, could be regulated by 5 upregulated circRNAs. In addition, we screened out EMT-related DE-mRNAs, including 6 upregulated DE-mRNAs and 6 downregulated DE-mRNAs. The EMT-related circRNA-miRNA-mRNA network was established with the top 10 circRNAs, 8 validated miRNAs (upregulated miR-17-5p, miR-181a-5p, and miR-106a-5p, downregulated miR-124-3p, miR-9-5p, miR-130b-5p, miR-1-3p, and miR-26b-5P), and 12 EMT-related DE-mRNAs. We found that hsa_circ_0002406 might upregulate FN1 and ADAM12 by sponging miR-26b-5p and miR-1-3p, respectively, thus promoting EMT in pterygium. Briefly, the study provides a novel viewpoint on the molecular pathological mechanisms in pterygium formation. CircRNA-miRNA-mRNA regulatory networks participate in the pathogenesis of pterygium and might become promising targets for pterygium prevention and treatment.

RNA-binding protein MEX3D promotes cervical carcinoma tumorigenesis by destabilizing TSC22D1 mRNA

RNA-binding proteins (RBPs) have been related to cancer development. Their functions in cervical cancer, however, are virtually unknown. One of these proteins, Mex-3 RNA-binding family member D (MEX3D), has been recently found to exhibit oncogenic properties in a variety of cancer types. In this present study, the functional roles and the regulatory mechanisms underlying MEX3D were examined in cervical cancer. The detection of MEX3D mRNA expression levels in cervical tissues was performed using reverse transcription-quantitative PCR. For functional analysis, for detecting apoptosis and cell proliferation in cervical cancer cells, the Cell Counting Kit-8, colony formation, and flow cytometry were utilized (SiHa and CaSki). The potential mechanisms of MEX3D were assessed and elucidated utilizing western blot analysis, RNA pull-down, RNA immunoprecipitation, and mRNA stability assays. For verification of MEX3D role in vivo, mouse xenograft models were established. When compared to normal cervical tissues, MEX3D expression was observed to be higher in cervical cancer tissues. MEX3D expression was increased in human papillomavirus (HPV) 16 positive cervical cancer tissues and positively regulated by HPV16 E7. When MEX3D expression was knocked down in cervical cancer cells, cell proliferation was decreased, colony formation was inhibited, and apoptosis was promoted. Furthermore, in a mouse xenograft model, knocking down MEX3D expression reduced cervical cancer tumor growth. In addition, MEX3D acted as an RBP to reduce TSC22 domain family protein 1 (TSC22D1) mRNA stability by directly binding to TSC22D1 mRNA. The findings revealed that MEX3D is upregulated by HPV16 E7 and has a crucial oncogenic in cervical cancer development via sponging TSC22D1 for destabilizing its mRNA levels. According to the findings of this study, MEX3D may be a potential therapeutic target for treating cervical cancer patients.