LINC00955 suppresses colorectal cancer growth by acting as a molecular scaffold of TRIM25 and Sp1 to Inhibit DNMT3B-mediated methylation of the PHIP promoter.

BACKGROUND: Long non-coding RNAs play an important role in the development of colorectal cancer (CRC), while many CRC-related lncRNAs have not yet been identified. METHODS: The relationship between the expression of LINC00955 (Long Intergenic Non-protein Coding RNA 955) and the prognosis of colorectal cancer patients was analyzed using the sequencing results of the TCGA database. LINC00955 expression levels were measured using qRT-PCR. The anti-proliferative activity of LINC00955 was evaluated using CRC cell lines in vitro and xenograft models in nude mice in vivo. The interaction of TRIM25-Sp1-DNMT3B-PHIP-CDK2 was analyzed by western blotting, protein degradation experiment, luciferase, RNA-IP, RNA pull-down assays and immunohistochemically analysis. The biological roles of LINC00955, tripartite motif containing 25 (TRIM25), Sp1 transcription factor (Sp1), DNA methyltransferase 3 beta (DNMT3B), pleckstrin homology domain interacting protein (PHIP), cyclin dependent kinase 2 (CDK2) in colorectal cancer cells were analyzed using ATP assays, Soft agar experiments and EdU assays. RESULTS: The present study showed that LINC00955 is downregulated in CRC tissues, and such downregulation is associated with poor prognosis of CRC patients. We found that LINC00955 can inhibit CRC cell growth both in vitro and in vivo. Evaluation of its mechanism of action showed that LINC00955 acts as a scaffold molecule that directly promotes the binding of TRIM25 to Sp1, and promotes ubiquitination and degradation of Sp1, thereby attenuating transcription and expression of DNMT3B. DNMT3B inhibition results in hypomethylation of the PHIP promoter, in turn increasing PHIP transcription and promoting ubiquitination and degradation of CDK2, ultimately leading to G0/G1 growth arrest and inhibition of CRC cell growth. CONCLUSIONS: These findings indicate that downregulation of LINC00955 in CRC cells promotes tumor growth through the TRIM25/Sp1/DNMT3B/PHIP/CDK2 regulatory axis, suggesting that LINC00955 may be a potential target for the therapy of CRC.

Forward genetic analysis of monensin and diclazuril resistance in Eimeria tenella.

Worldwide distributed coccidiosis is caused by infection of both Eimeria species and Cystoisospora in the host intestine and causes huge economic losses to the livestock industry, especially the poultry industry. The control of such diseases relies mainly on chemoprophylaxis with anticoccidials, which has led to a very common drug resistance in this field. However, the genetic mechanisms underlying resistance to many anticoccidial drugs remain unknown. In this study, strains of E. tenella resistant to 250 mg/kg monensin were generated and characterized. Forward genetic approaches based on pooled genome sequencing, including experimental evolution and linkage group selection, were used to locate candidate targets responsible for resistance to monensin and diclazuril in E. tenella. A total of 16 nonsynonymous mutants in protein-coding genes were identified in monensin-resistant strains, and two genomic regions with strong selection signals were also detected in diclazuril-resistant strains. Our study reveals the genetic characterization of the experimental evolution and linkage group selection in Eimeria species, and also provides important information that contributes to the understanding of the molecular mechanism of drug resistance in coccidia.

Downregulation of TEX11 promotes S-Phase progression and proliferation in colorectal cancer cells through the FOXO3a/COP1/c-Jun/p21 axis.

Colorectal cancer (CRC) is the most common digestive tract malignancy, attributing to approximately 9.4% of global cancer-related deaths. However, the pathogenesis of CRC is poorly understood. The testis-expressed 11 (TEX11) gene is located on the X chromosome and is required for spermatogenesis, and is reported might serve as a biomarker for early onset CRC according to database analysis. However, the role played by TEX11 in cancer progression remains to be investigated. In this study, we show that TEX11 expression is significantly downregulated in CRC cell lines and clinical CRC tissue samples, and TEX11 expression correlates with poor prognosis in CRC patients. We further demonstrate that TEX11 can significantly inhibit the proliferative capacity of CRC cells in vitro and in vivo. Mechanistically, we demonstrate that TEX11 promotes transcription of COP1 by upregulating FOXO3a expression. This enhanced COP1 expression subsequently accelerates the degradation of the negative transcriptional regulator c-Jun, which, in turn, enhances p21 transcription inhibiting CRC cell cycle progression and proliferation. Overall, our findings suggest that TEX11 may be a valuable therapeutic target for the treatment of CRC.

Downregulation of microRNA-6125 promotes colorectal cancer growth through YTHDF2-dependent recognition of N6-methyladenosine-modified GSK3ß.

BACKGROUND: MicroRNAs (miRNAs), the key regulator of gene expression, and N6-methyladenosine (m6A) RNA modification play a significant role in tumour progression. However, regulation of m6A-modified mRNAs by miRNAs in colorectal cancer (CRC), and its effect on progression of CRC, remains to be investigated. METHODS: Expression of miR-6125 and YTH Domain-Containing Family Protein 2 (YTHDF2) was detected by western blotting and immunohistochemistry. The effects of miR-6125 and YTHDF2 on proliferative capacity of CRC cells were analysed using soft agar, ATP, CCK8 and EdU assays, and in animal experiments. RESULTS: MiR-6125 expression was downregulated markedly in CRC, and expression correlated negatively with tumour size and prognosis. MiR-6125 targeted the 3'-UTR of YTHDF2 and downregulated the YTHDF2 protein, thereby increasing the stability of m6A-modified glycogen synthase kinase 3 beta (GSK3ß) mRNA. Increased GSK3ß protein levels inhibited the expression of Wnt/ß-catenin/Cyclin D1 pathway-related proteins, leading to G0-G1 phase arrest and ultimately inhibiting the proliferation of CRC cells. CONCLUSIONS: MiR-6125 regulates YTHDF2 and thus plays a critical role in regulating the Wnt/ß-catenin pathway, thereby affecting the growth of CRC. Collectively, these results suggest that miR-6125 and YTHDF2 are potential targets for treatment of CRC.