circRNA circFAT1(e2) Elevates the Development of Non-Small-Cell Lung Cancer by Regulating miR-30e-5p and USP22

The Relationship Between the Expression of circFAT1 and Immune Cell in Patients with Non-Small Cell Lung Cancer

Objective

To analyze the correlation between the expression of circFAT1 in serum and immune cells in patients with non-small cell lung cancer (NSCLC).

Methods

A total of 96 patients with NSCLC admitted to our hospital from November 2019 to November 2022 were regarded as the study subjects. In the meantime, 96 volunteers who had physical examination in our hospital were regarded as the control group. The expression level of circFAT1 in serum was detected by real-time fluorescence quantitative PCR. NSCLC cancer tissue (NSCLC group) and paracancerous tissue (tissue ≥ 2cm away from the focus) (paracancerous group) were collected during the operation, the expression of CD4+, CD8+ and Foxp3+ in tissues was determined by immunohistochemistry; the expression level of circFAT1 mRNA in NSCLC tissue was analyzed using the Ualcan database. Spearman correlation was applied to analyze the correlation between the expression of circFAT1 and immune cells (CD4+, Foxp3+, CD8+).

Results

The level of circFAT1 in NSCLC tissue was higher than that in normal tissue (P < 0.05). Compared with the control group, the expression level of circFAT1 in serum of NSCLC group was obviously higher (P < 0.05). The expression level of circFAT1 was related to lymph node metastasis, TNM stage and differentiation (P < 0.05). Compared with the paracancerous group, the positive expression rate of CD8+ in NSCLC group was obviously lower, and the positive expression rates of CD4+ and Foxp3+ were obviously higher (P < 0.05). The expression of CD4+, Foxp3+ and CD8+ in NSCLC patients' cancer tissue was related to lymph node metastasis, TNM stage and differentiation degree (P < 0.05). Spearman correlation analysis showed that circFAT1 was positively correlated with the expression of CD4+ and Foxp3+ and negatively correlated with the expression of CD8+ (P < 0.05).

Conclusion

CircFAT1 is highly expressed in the serum of NSCLC patients and is closely related to immune cells.

Circular RNAs: Emerging roles and new insights in human cancers

Circular RNAs (circRNAs) are single-stranded, covalently closed RNA molecules formed by mRNA exon back-splicing. Although the circRNA functions remain largely unknown, their currently known biological activities include: acting as competing endogenous RNA (ceRNA) to adsorb microRNA (miRNA), binding proteins, regulating transcription or splicing, and ability to be translated into proteins or peptides. A growing number of studies have found that many circRNAs are abnormally expressed in various cancers, and their dysregulation is highly correlated with tumor progression. Therefore, diagnosis and treatment using circRNAs as biomarkers and therapeutic targets, respectively, has gradually become an attractive research topic. In this review, we introduced the canonical biogenesis pathways and degradation mechanisms of circRNAs. In addition, we examined the biological functions of circRNAs in vivo. Finally, we discussed the current clinical applications and challenges faced by circRNA, and proposed future directions for this promising research field.

[MiR-30e-5p overexpression promotes proliferation and migration of colorectal cancer cells by activating the CXCL12 axis via downregulating PTEN]

OBJECTIVE

To investigate the regulatory effects of miR-30e-5p on biological behaviors of colorectal cancer cells and the role of PTEN/CXCL12 axis in mediating these effects.

METHODS

Bioinformatic analysis was performed to explore the differential expression of miR-30e-5p between colorectal cancer tissues and normal tissues. RT-qPCR was used to detect the differential expression of miR-30e-5p in intestinal epithelial cells and colorectal cancer cells. Bioinformatics and dual luciferase assay were used to predict and validate the targeting relationship between miR-30e-5p and PTEN. Human and murine colorectal cancer cell lines were transfected with miR-30e-5p mimics, miR-30e-5p inhibitor, miR-30e-5p mimics+LV-PTEN, or miR-30e-5p inhibitor + si-PTEN. The changes in biological behaviors of the cells were detected using plate clone formation assay, CCK-8 assay, flow cytometry, scratch healing and Transwell assays. PTEN and CXCL12 expressions in the cancer cells were detected by Western blotting. The effects of miR-30e-5p inhibitor on colorectal carcinogenesis and development were observed in nude mice.

RESULTS

Bioinformatic analysis showed that miR-30e-5p expression was significantly elevated in colorectal cancer tissues compared with the adjacent tissue (P < 0.01). Higher miR-30e-5p expression was detected in colorectal cancer cell lines than in intestinal epithelial cells (P < 0.01). Dual luciferase assay confirmed the targeting relationship between miR-30e-5p and PTEN (P < 0.05). Transfection with miR-30e-5p mimics significantly enhanced proliferation and metastasis and inhibited apoptosis of the colorectal cancer cells (P < 0.05), and co-transfection with LV-PTEN obviously reversed these changes (P < 0.05). MiR-30e-5p mimics significantly inhibited PTEN expression and enhanced CXCL12 expression in the cancer cells (P < 0.01), and miR-30e-5p inhibitor produced the opposite effect. Transfection with miR-30e-5p inhibitor caused cell cycle arrest in the cancer cells, which was reversed by co-transfection with si-PTEN (P < 0.05). In the in vivo experiments, the colorectal cancer cells transfected with miR-30e-5p inhibitor showed significantly lowered tumorigenesis.

CONCLUSION

Overexpression of miR-30e-5p promotes the malignant behaviors of colorectal cancer cells by downregulating PTEN to activate the CXCL12 axis.

CircFAT1 Promotes the Proliferation and Invasion of Malignant Melanoma through miR375-SLC7A11 Signal Axis

BACKGROUND

Circular RNA, as a member of noncoding RNA, plays an important role in the occurrence, development and metastasis of tumor cells. So far, the correlation between circular RNA and malignant melanoma remains obscure.

METHODS

RNA expression of circFAT1 and miR-375 in malignant melanoma (MM) tissues and cell lines was detected by RT-PCR. The proliferation, cloning, migration and invasion of SK-Mel-28 and A375 cells were assessed using CCK-8 test, clone formation and Transwell assay, respectively. CircRNA immunoprecipitation was used to validate the relationship between circFAT1 and miR-375. The binding between circFAT1 and miR-375, as well as SLC7A11 and miR-375 were verified by luciferase assay.

RESULTS

In our study，the circFAT1 was significantly overexpressed in the MM tissue than melanocytic nevi. Conversely, the expression of miR-375 in MM tissue was lower than in melanocytic nevi tissue. The underexpression of circFAT1 with siRNA plasmids significantly suppressed the proliferation, invasion and clone formation of MM cell line. Mechanistically, circFAT1 positively regulates the expression level of SLC7A11 by sponging miR-375. The promotive effects of circFAT1 on the proliferation and invasion ability of MM cells were reversed by the upregulation of miR-375.

CONCLUSION

circFAT1 promotes the proliferation, invasion and clone formation of malignant melanoma cells by improving the expression level of SLC7A11 via sponging miR-375.