Long non-coding RNAs (lncRNAs) function as key molecules in cancer progression. The lncRNA CYTOR plays oncogenic roles in multiple types of cancer, yet the detailed molecular mechanisms of those roles remain unknown. The aim of this study was to investigate the clinical significance, biological function and interacting partners of CYTOR in colorectal cancer (CRC). A systematic and comprehensive analysis of CYTOR expression was performed in 138 CRC samples and in the TCGA and GEO databases. Biological function was investigated through knockdown and overexpression of CYTOR in vitro and in vivo. In addition, its protein binding partner was identified and validated using ChIRP-MS and RNA immunoprecipitation assays. Their key interaction sites on CYTOR were verified by CRISPR/Cas9 and a series of mutant constructs. Furthermore, the downstream targets of CYTOR were confirmed via immunoblotting and luciferase reporter assays. CYTOR was significantly up-regulated in CRC samples and associated with poor prognosis, promoting proliferation and metastasis in vitro and in vivo. NCL and Sam68 could recognize their specific motifs and directly bind to EXON1 of CYTOR. Moreover, EXON1 was the key functional site mediating the interaction of CYTOR with NCL and Sam68. NCL and Sam68 functioned as oncogenes to promote CRC progression. Furthermore, we confirmed that the heterotrimeric complex of CYTOR, NCL and Sam68 activated the NF-κB pathway and EMT to contribute to CRC progression. CYTOR plays important roles in CRC progression by interacting with NCL and Sam68 and may serve as a prognostic biomarker and/or an effective target for CRC therapies.

Background: Sam68, an RNA-binding protein, exerts oncogenic functions in several types of cancer. However, the specific functions and mechanisms of Sam68 in colorectal cancer (CRC) had not been previously clarified. Pyruvate kinase muscle (PKM)2 is the key rate-limiting enzyme in glycolysis, and PKM2 maintains the glycolysis-dominant energy metabolism in most cancer cells. Methods: CCK8 assay was performed to show the effect of Sam68 on cell growth. Pyruvate kinase activity and lactate detection assays were performed to analyze the effects of Sam68 on aerobic glycolysis. RNA immunoprecipitation (RIP) was used to detect the binding of Sam68 to the PKM2 sequence. Western blot and real-time PCR were executed to analyze the regulation of PKM2 by Sam68. Results: Gain-of-function and loss-of-function studies showed that ectopic expression of Sam68 promoted glycolysis and cell proliferation in CRC cells, whereas Sam68 knockdown inhibited glycolysis and cell proliferation. Mechanically, Sam68 modulated the expression profile of pyruvate kinase (PKM2 or PKM1) by regulating its alternative splicing. Overexpression of Sam68 was associated with decreased PKM1/PKM2 ratio, which positively contributed to the glycolysis procedure. Sam68 significantly promoted cell proliferation and caused a decrease of PKM1/PKM2 ratio, resulting in the metabolism of glucose switched from oxidative phosphorylation to glycolysis in CRC cells. Besides, Sam68 enhanced PKM2 mRNA transport from the nucleus to cytoplasm and increased the expression of PKM2 protein, resulting in elevated pyruvate kinase activity and lactate production. Conclusions: These findings suggested that Sam68 affected cell growth and glycolysis pathway by regulating the alternative splicing and expression of PKM2 in CRC.

Gout is a form of prevalent and painful inflammatory arthritis characterized by elevated serum urate (SUA) levels. The gut microbiota (GM) is believed to influence the development of gout and SUA levels. Our study aimed to explore the causal relationship between GM composition and gout, as well as SUA levels, utilizing a two-sample Mendelian Randomization (MR) approach. A total of 196 GM taxa from five levels were available for analysis. We identified five taxa associated with SUA levels and 10 taxa associated with gout. In reverse MR analysis, we discovered that gout affected the composition of five GM taxa, while SUA levels influenced the composition of 30 GM taxa. Combining existing research, our study unveiled a potential negative feedback loop between phylum Actinobacteria and SUA levels, establishing connections with gout. We also proposed two novel associations connecting GM taxa (genus Faecalibacterium and genus Prevotella9), SUA levels, and gout. These findings provide compelling evidence of causal relationships between specific GM taxa with SUA levels and gout, contributing valuable insights for the treatment of gout.

Background: Elongin A (ELOA), our previous work revealed, serves as a novel tumor suppressor in colorectal cancer. However, the function and mechanism of ELOA in other cancer types, including gastric cancer (GC), remain to be elucidated.Methods: The expression of ELOA was measured by quantitative reverse transcription‐polymerase chain reaction and western blot. The effects of ELOA on GC growth and metastasis were assessed through a series of in‐vitro and in‐vivo assays. Furthermore, the potential mechanism of ELOA was revealed by RNA sequencing, dual luciferase reporter assay, chromatin immunoprecipitation, and rescue experiments in GC.Results: We uncovered increased expression of ELOA in GC tissues compared with paired normal tissues via bioinformatic analyses and our sample detection. Enhanced ELOA expression in GC tissues was obviously correlated with poor tumor differentiation, lymph node metastasis, advanced tumor stage, and a poor prognosis. A series of functional experiments showed that ELOA promoted the proliferation and metastasis of GC. Mechanistically, we revealed that the decreased levels of miR‐490‐3p caused the upregulation of ELOA in GC. Both RNA‐seq and ChIP assays revealed that ELOA transcriptionally activated retinol‐binding protein 1 (RBP1) by binding to its promotor. Furthermore, specific knockdown of RBP1 reduced the tumor‐promoting ability of ELOA in GC cells.Conclusions: In summary, our findings demonstrate that ELOA exerts oncogenic properties by activating RBP1 expression, providing the basis for a promising therapeutic target in GC.

Background Colorectal cancer (CRC) stands as one of the most serious threats to human health, with its mortality rate increase during the past years. Low diagnostic accuracy, poor prognosis, and high recurrence rates attributed to the high mortality rate of CRC. Consequently, the urgency to identify potential diagnose and biological targets for intervention in this disease. Among the various molecular factor associated with this disease, circular RNAs (circRNAs) have been a hot topic. These noncoding RNA molecules, characterized by their unique closed loop structure, displayed close associations with the progression of tumors. Methods Actinomycin D experiment and RNA digestion experiment were used to verify the circular structure characteristics of circWDR78. Proliferation and motility ability of circWDR78 was evaluated by in vitro functional experiment. We also used RNA-seq technology to explore the signal pathways and genes it might regulate. Finally, the luciferase assay and qRT-PCR experiment proved that circWDR78 could sponge miR-653-3p, and confirmed that RGS4 is the downstream target of miR-653-3p. Results This study demonstrated that circWDR78 is lower expression in colorectal cancer tissues, revealing its capacity to inhibit proliferation, colony forming ability and cell motility. These findings hint at a potential correlation between its downregulation and the progression of CRC. Mechanistically, we found that circWDR78 could sponge miR-653-3p and identified RGS4 as a novel target of miR-653-3p. Conclusion This discovery highlights the significance of circWDR78 as a potential regulatory axis of miR-653-3p/RGS4 in CRC progression.