Overexpression of miR-106a enhances oxaliplatin sensitivity of colorectal cancer through regulation of FOXQ1

Hsa-miR-483-5p/mRNA network that regulates chemotherapy resistance in locally advanced rectal cancer identified through plasma exosome transcriptomics

BACKGROUND

Chemoresistance is the primary contributor to distant metastasis in the context of neoadjuvant chemoradiotherapy (nCRT) for rectal cancer. However, the underlying mechanisms remain elusive.

AIM

To detect the differential expression profiles of plasma exosomal microRNAs (miRNAs) in poor and good responders and explore the potential mechanisms of chemoresistance.

METHODS

In this study, the profiles of plasma exosomal miRNAs were compared in two dimensions according to treatment responses (poor/good responders) and treatment courses (pre/post-nCRT) using RNA sequencing.

RESULTS

Exosome hsa-miR-483-5p was up-regulated in good responders post-nCRT. Bioinformatics analysis revealed that the target genes of hsa-miR-483-5p were mainly enriched in tumor-specific pathways, such as the MAPK signaling pathway, EGFR tyrosine kinase inhibitor resistance, Toll-like receptor signaling pathway, VEGF signaling pathway, and mTOR signaling pathway. Further analysis indicated that MAPK3, RAX2, and RNF165 were associated with inferior recurrence-free survival in patients with rectal cancer, and the profiles of MAPK3, TSPYL5, and ZNF417 were correlated with tumor stage. In addition, the expression profiles of MAPK3, RNF165, and ZNF417 were negatively correlated with inhibitory concentration 50 values. Accordingly, an hsa-miR-483-5p/MAPK3/RNF 165/ZNF417 network was constructed.

CONCLUSION

This study provides insights into the mechanism of chemoresistance in terms of exosomal miRNAs. However, further research is required within the framework of our established miRNA-mRNA network.

LINC00887 Acts as an Enhancer RNA to Promote Medullary Thyroid Carcinoma Progression by Binding with FOXQ1

BACKGROUND

Medullary thyroid carcinoma (MTC) is a rare but aggressive endocrine malignancy that originates from the parafollicular C cells of the thyroid gland. Enhancer RNAs (eRNAs) are non-coding RNAs transcribed from enhancer regions, which are critical regulators of tumorigenesis. However, the roles and regulatory mechanisms of eRNAs in MTC remain poorly understood. This study aims to identify key eRNAs regulating the malignant phenotype of MTC and to uncover transcription factors involved in the regulation of key eRNAs.

METHODS

GSE32662 and GSE114068 were used for the identification of differentially expressed genes, eRNAs, enhancers and enhancer-regulated genes in MTC. Metascape and the transcription factor affinity prediction method were used for gene function enrichment and transcription factor prediction, respectively. qRT-PCR was used to detect gene transcription levels. ChIP-qPCR was used to assess the binding of histone H3 lysine 27 acetylation (H3K27ac)-enriched regions to anti- H3K27ac. RIP-qPCR was used to detect the binding between FOXQ1 and LINC00887. CCK8 and Transwell were performed to measure the proliferation and invasion of MTC cells, respectively. Intracellular reactive oxygen species (ROS) levels were quantified using a ROS assay kit.

RESULTS

Four eRNAs (H1FX-AS1, LINC00887, MCM3AP-AS1 and A1BG-AS1) were screened, among which LINC00887 was the key eRNA promoting the proliferation and invasion of MTC cells. A total of 135 genes controlled by LINC00887-regulated enhancers were identified; among them, BCL2, PRDX1, SFTPD, TPO, GSS, RAD52, ZNF580, and ZFP36L1 were significantly enriched in the "ROS metabolic process" term. As a transcription factor regulating genes enriched in the "ROS metabolic process" term, FOXQ1 could recruit LINC00887. Overexpression of FOXQ1 restored LINC00887 knockdown-induced downregulation of GSS and ZFP36L1 transcription in MTC cells. Additionally, FOXQ1 overexpression counteracted the inhibitory effects of LINC00887 knockdown on the proliferation and invasion of MTC cells and the promotion of intracellular ROS accumulation induced by LINC00887 knockdown.

CONCLUSION

LINC00887 was identified as a key eRNA promoting the malignant phenotype of MTC cells. The involvement of FOXQ1 was essential for LINC00887 to play a pro-tumorigenic role in MTC. Our findings suggest that the FOXQ1/LINC00887 axis is a potential therapeutic target for MTC.

Dysregulated microRNAs participate in the crosstalk between colorectal cancer and atrial fibrillation

Colorectal cancer and atrial fibrillation share several common risk factors, and the incidence of the two diseases also exhibits a certain correlation. The above facts suggest a potential interaction mechanism between them, which has obtained increasing attention in the scientific community but remains to be further explored. Participating in diverse physiological and pathological processes, miRNAs exert important roles in both occurrence and growth of colorectal cancer and atrial fibrillation. To fill the gap in the understanding of the potential linkage between two diseases, the present study collected dysregulated miRNAs of colorectal cancer and atrial fibrillation from previous studies and then selected the miRNAs with the same change trends in both diseases. Finally, we reviewed the potential crosstalk of two diseases focusing on the roles of 6 dysregulated miRNAs, including 3 co-downregulated miRNAs (hsa-mir-126, hsa-mir-133a and hsa-mir-150) and 3 co-upregulated miRNAs (hsa-mir-106a, hsa-mir-155 and hsa-mir-21). The molecular mechanisms mediated by these miRNAs in colorectal cancer and atrial fibrillation were reviewed, and the possible crosstalk between the two diseases was discussed from the perspective of miRNAs. This study also provides potential common targets for preventive and curative measures against both colorectal cancer and atrial fibrillation.

Identification of Hub Genes and Construction of a Transcriptional Regulatory Network Associated With Tumor Recurrence in Colorectal Cancer by Weighted Gene Co-expression Network Analysis

Tumor recurrence is one of the most important risk factors that can negatively affect the survival rate of colorectal cancer (CRC) patients. However, the key regulators dictating this process and their exact mechanisms are understudied. This study aimed to construct a gene co-expression network to predict the hub genes affecting CRC recurrence and to inspect the regulatory network of hub genes and transcription factors (TFs). A total of 177 cases from the GSE17536 dataset were analyzed via weighted gene co-expression network analysis to explore the modules related to CRC recurrence. Functional annotation of the key module genes was assessed through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses. The protein and protein interaction network was then built to screen hub genes. Samples from the Cancer Genome Atlas (TCGA) were further used to validate the hub genes. Construction of a TFs-miRNAs–hub genes network was also conducted using StarBase and Cytoscape approaches. After identification and validation, a total of five genes (TIMP1, SPARCL1, MYL9, TPM2, and CNN1) were selected as hub genes. A regulatory network of TFs-miRNAs-targets with 29 TFs, 58 miRNAs, and five hub genes was instituted, including model GATA6-MIR106A-CNN1, SP4-MIR424-TPM2, SP4-MIR326-MYL9, ETS1-MIR22-TIMP1, and ETS1-MIR22-SPARCL1. In conclusion, the identification of these hub genes and the prediction of the Regulatory relationship of TFs-miRNAs-hub genes may provide a novel insight for understanding the underlying mechanism for CRC recurrence.

miR-140-3p inhibits bladder cancer cell proliferation and invasion by targeting FOXQ1

Upregulation of the forkhead box protein Q1 (FOXQ1) promotes bladder cancer (BCa) cell growth and metastasis. Factors affecting FOXQ1 expression at the post-transcriptional level have not yet been identified. We performed cell proliferation, cell invasion, and tumorigenesis experiments to characterize the relationship between FOXQ1 and miR-140-3p. We found that FOXQ1 was significantly upregulated and miR-140-3p was significantly downregulated in BCa tissues. We also identified an inverse correlation between miR-140-3p and FOXQ1 expression in BCa tissues. Overexpression of miR-140-3p reduced FOXQ1 expression, suppressing BCa cell proliferation and invasion. A luciferase assay confirmed that miR-140-3p bound to the 3’-UTR of FOXQ1 mRNA and decreased its expression. In addition, we used a mouse xenograft model to demonstrate that miR-140-3p suppressed tumor cell growth in vivo. Our findings suggest that miR-140-3p suppresses BCa cell proliferation and invasion by directly decreasing FOXQ1 expression.