DDX10 promotes the proliferation and metastasis of colorectal cancer cells via splicing RPL35.

BACKGROUND: Colorectal cancer (CRC) has become the second deadliest cancer in the world and severely threatens human health. An increasing number of studies have focused on the role of the RNA helicase DEAD-box (DDX) family in CRC. However, the mechanism of DDX10 in CRC has not been elucidated. METHODS: In our study, we analysed the expression data of CRC samples from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. Subsequently, we performed cytological experiments and animal experiments to explore the role of DDX10 in CRC cells. Furthermore, we performed Gene Ontology (GO)/Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and protein-protein interaction (PPI) network analyses. Finally, we predicted the interacting protein of DDX10 by LC-MS/MS and verified it by coimmunoprecipitation (Co-IP) and qPCR. RESULTS: In the present study, we identified that DDX10 mRNA was extremely highly expressed in CRC tissues compared with normal colon tissues in the TCGA and GEO databases. The protein expression of DDX10 was measured by immunochemistry (IHC) in 17 CRC patients. The biological roles of DDX10 were explored via cell and molecular biology experiments in vitro and in vivo and cell cycle assays. We found that DDX10 knockdown markedly reduced CRC cell proliferation, migration and invasion. Then, we constructed a PPI network with the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING). GO and KEGG enrichment analysis and gene set enrichment analysis (GSEA) showed that DDX10 was closely related to RNA splicing and E2F targets. Using LC-MS/MS and Co-IP assays, we discovered that RPL35 is the interacting protein of DDX10. In addition, we hypothesize that RPL35 is related to the E2F pathway and the immune response in CRC. CONCLUSIONS: In conclusion, provides a better understanding of the molecular mechanisms of DDX10 in CRC and provides a potential biomarker for the diagnosis and treatment of CRC.

Noncoding RNAs-based high KIF26B expression correlates with poor prognosis and tumor immune infiltration in colon cancer.

BACKGROUND: The protein kinesin family member 26B (KIF26B) is aberrantly expressed in various cancers. However, its particular role and association with tumor immune infiltration in colon adenocarcinoma (COAD) remain unclear. METHODS: All original data were downloaded directly from The Cancer Genome Atlas (TCGA), UCSC Xena, and Gene Expression Omnibus (GEO) databases and processed with R 3.6.3. KIF26B expression was analyzed using Oncomine, TIMER, TCGA, GEO databases, and our clinical specimens. KIF26B expression at the protein level was explored with Human Protein Atlas (HPA) database. The upstream miRNAs and lncRNAs were predicted by StarBase and validated using RT-qPCR. Correlation of KIF26B expression with the expression of immune-related or immune checkpoint genes and GSEA analysis of KIF26B-related genes were investigated via R software. Relationship of KIF26B expression with immune biomarkers or tumor immune infiltration levels was studied through GEPIA2 and TIMER databases. RESULTS: KIF26B was upregulated, and its overexpression was closely related to overall survival (OS), disease-specific survival (DSS), progression-free interval (PFI), T stage, N stage, and CEA levels in COAD. MIR4435-2HG/hsa-miR-500a-3p/KIF26B axis was identified as the promising regulatory pathway of KIF26B. KIF26B expression was positively correlated with immune-related genes, tumor immune infiltration, and biomarker genes of immune cells in COAD, and KIF26B-related genes were significantly enriched in macrophage activation-related pathways. Expression of immune checkpoint genes, including PDCD1, CD274, and CTLA4, was also closely related to KIF26B expression. CONCLUSIONS: Our results clarified that ncRNA-based increased KIF26B expression was associated with a worse prognosis and high tumor immune infiltration in COAD.

Cancer-associated fibroblast-targeted nanodrugs reshape colorectal tumor microenvironments to suppress tumor proliferation, metastasis and improve drug penetration.

Cancer-associated fibroblasts (CAFs) produce a critical tumor-promoting effect by cellular crosstalk with cancer cells and remodel the extracellular matrix (ECM) to form a protective physical barrier. The simple elimination of CAFs is not sufficient to govern the CAF-shaped aggressive tumor microenvironment (TME) because of the complexity of tumors. Herein, a CAF-targeted poly (lactic-co-glycolic acid) (PLGA) nanoemulsion is tailored to simultaneously deliver doxorubicin (DOX) and small interfering RNA (siRNA) targeting hepatocyte growth factor (HGF) for the combination of chemotherapy and gene therapy. The nanoemulsion (apt-Si/DNPs) shows a high specificity towards CAFs due to the aptamer modification and efficiently induces the apoptosis of CAFs, thus decreasing ECM deposition in the TME. Importantly, the delivered siRNA reduces the expression of the HGF in the remaining CAFs, which overcomes chemotherapy-induced upregulation of HGF mRNA and prevents the reproduction of CAFs through the autocrine HGF closed-loop. Owing to these synergetic effects, tumor proliferation, migration and invasion are prominently inhibited and tumor permeability is improved significantly. Overall, these results emphasize the potential of CAF-targeted combination treatments to inhibit tumor progression and metastasis, as well as overcome therapeutic resistance.

Na+/H+-Exchanger Family as Novel Prognostic Biomarkers in Colorectal Cancer.

BACKGROUND: The acidic characteristics of the tumor microenvironment (TME) are attributed to cancer cells' needs of metabolism which produce a large amount of H+. In order not to affect its own life activities, it needs to release H+ into the intercellular space through an efficient Na+/H+ exchanger. On account of the intestine whose physiological function is highly dependent on intestinal pH value, NHE family members may play a critical role in the occurrence and development of colorectal cancer (CRC). METHODS: TCGA, GEPIA2, ONCOMINE, UALCAN, STRING, TIMER, Cytoscape, TargetScan, ENCORI, LncBase v.2, DNMIVD, HPA, and CellMinerTM databases were used in our study. RESULTS: The mRNA expressions of SLC9A1, SLC9A2, SLC9A3, and SLC9A9 were evidently lower in COAD than in normal samples; however, the mRNA expressions of SLC9A5, SLC9A8, and SLC9B2 were higher. Besides, mRNA expressions of NHE family were extremely associated with clinicopathological features, tumor immune microenvironment and stemness score, DNA methylation, and patient prognosis in COAD. Moreover, we conjectured that NHE family may play a role through MAPK or ErbB signaling pathway according to the results of GO/KEGG enrichment analysis. At last, we found that NHE family members were key factors of various kinds of cancers. CONCLUSION: Our study indicated that NHE family represented new diagnostic and therapeutic targets for CRC, which could have important significance for the clinical treatment of CRC.