Dysregulation of miR-638 in the progression of cancers

MicroRNA expression associated with low-grade cervical intraepithelial neoplasia outcomes

PURPOSE

Only a fraction of low-grade cervical intraepithelial neoplasia (CIN) progresses to high-grade CIN; however, the biological processes that differentiate progressive CIN from CIN that resolves naturally are poorly understood. MicroRNAs (miRNAs) are important epigenetic regulators of gene expression and thus, miRNA expression profiling can reveal the dysregulated biology underlying disease processes. The purpose of this case-control study was to reveal miRNA expression patterns and predict the underlying biological pathways that are associated with clinical outcomes of low-grade CIN.

METHODS

Women with low-grade CIN diagnosis and definitive clinical outcomes (n = 51) were identified retrospectively using electronic clinical records. Comprehensive miRNA expression profiling was performed on the low-grade CIN diagnostic cervical biopsies retrieved from pathology archives. Differential miRNA expression was analyzed by comparing women with CIN that progressed to women with CIN that resolved naturally.

RESULTS

Differential expression of 29 miRNAs was observed in low-grade CIN that progressed to high-grade compared to low-grade CIN that resolved. Of these, 24 were significantly downregulated in progressive CIN, including miR-638, miR-3196, miR-4488, and miR-4508, while 5 miRNAs, including miR-1206a, were significantly upregulated. Computational gene ontology analysis based on the discovered miRNAs and their putative mRNA targets revealed biological processes associated with oncogenic phenotypes.

CONCLUSION

Distinct miRNA expression profiles are associated with clinical outcomes of low-grade CIN. The functional effects of the differentially expressed miRNAs may be biological determinants of CIN progression or resolution.

CircNCOR1 regulates breast cancer radiotherapy efficacy by regulating CDK2 via hsa-miR-638 binding

BACKGROUND

Despite aggressive local and regional therapy, triple-negative breast cancer (TNBC) is characterized by an increased risk of locoregional recurrence. RNA-sequencing data has identified a large number of circRNAs in primary breast cancers, but the role of specific circRNAs in regulating the radiosensitivity of TNBC is not fully understood. This research aimed to investigate the function of circNCOR1 in the radiosensitivity of TNBC.

METHODS

CircRNA high-throughput sequencing was conducted on two breast cancer MDA-MB-231 and BT549 cell lines after 6 Gy radiation. The relationship between circNCOR1, hsa-miR-638, and CDK2 was determined by RNA immunoprecipitation (RIP), FISH and luciferase assays. The proliferation and apoptosis of breast cancer cells were measured by CCK8, flow cytometry, colony formation assays, and western blot.

RESULTS

Differential expression of circRNAs was closely related to the proliferation of breast cancer cells after irradiation. Overexpression of circNCOR1 facilitated the proliferation of MDA-MB-231 and BT549 cells and impaired the radiosensitivity of breast cancer cells. Additionally, circNCOR1 acted as a sponge for hsa-miR-638 to regulate the downstream target protein CDK2. Overexpression of hsa-miR-638 promoted apoptosis of breast cancer cells, while overexpression of CDK2 alleviated apoptosis and increased proliferation and clonogenicity. In vivo, overexpression of circNCOR1 partially reversed radiation-induced loosening of tumor structures and enhanced tumor cell proliferation.

CONCLUSION

Our results demonstrated that circNCOR1 bounds to hsa-miR-638 and targets CDK2, thereby regulating the radiosensitivity of TNBC.

Expression level and function analysis of serum miRNAs in workers with occupational exposure to benzene series

Benzene series are ubiquitous in industrial production and daily life, and can have an impact on health even at low concentrations. miRNAs have been proved to be a biomarker of a variety of diseases and carcinogens. The purpose of this study was to explore the distribution characteristics and biological function of miRNAs in subjects exposed to benzene series. In this study, serum miRNAs were measured in 247 occupationally exposed subjects and 256 controls. The relationship between cumulative exposure dose of benzene series and miRNAs was analyzed by Generalized linear model, Spearman's rank correlation, and chi-square test for trend. The function of MiRNAs target gene was analyzed by means of bioinformatics method. The results showed that the expressions of miR-181a-5p, 221-3p, 223-3p, and 342-3p were down-regulated, whilst the expression of miR-638 was up-regulated in the occupational exposure group. miR-181a-5p, 221-3p, 223-3p, 342-3p, and 638 showed dose-response relationship with benzene series, and were closely related to multiple tumor pathways. miR-181a-5p, 221-3p, 223-3p, 342-3p, and 638 may be involved in the carcinogenic process of benzene series, and can be used to evaluate the early biological effects and monitor the exposure level of benzene series. miRNAs are potential biomarkers of benzene series exposure.

Immune Cell-Derived Extracellular Vesicles in the Face of Pathogenic Infections

Extracellular Vesicles (EVs) are a collection of vesicles released from cells that play an important role in intercellular communication. Microbial infections are known as one of the major problems in the medical field. Considering the increasing resistance of strains to routine drug treatments, the need for new therapies seems to be more than ever. Recent studies have shown that the EVs released from immune cells during microbial infections had anti-microbial effects or were able to induce neighbouring cells to display anti-microbial effects. This mini-review aimed to explore the latest studies on immune cell-derived EVs in viral, bacterial, fungal, and parasitic infections. Review of the literature demonstrated that specific cargos in EVs were involved in the fight against pathogenic infections. Additionally, the transport of appropriate bioactive molecules including miRNAs, mRNAs, and proteins via EVs could mediate the anti-microbial process. Thus, it could be a proof-of-principle that therapeutic approaches based on EVs derived from immune cells could offer a promising path forward, which is still in early stages and needs further assessments.

Hsa_circ_0008344 Promotes Glioma Tumor Progression and Angiogenesis Presumably by Regulating miR-638/SZRD1 Pathway

Hsa_circRNA_0008344 (circ_0008344) is a new glioma-related circular RNA. Our study aims to explore its functions in glioma tumor progression. Real-time quantitative PCR and western blotting were used to detect RNA and protein abundances. RNase R assay, actinomycin D assay, and subcellular fractionation method were performed to identify the features of circ_0008344. Cell-counting kit-8, 5-ethynyl-2'-deoxyuridine assays, transwell assays, tube formation assay, flow cytometry, and nude mice xenograft tumor model were performed. Target relationship was predicted by bioinformatics algorithms and confirmed by dual-luciferase reporter assay. Abundances of circ_0008344 and SUZ RNA binding domain containing 1 (SZRD1) were highly elevated, while miR-638 was downregulated in glioma tumors and cells. Circ_0008344 was identified as a stable circRNA with a circular structure. Silencing circ_0008344 could restrain glioma proliferation, migration, invasion, and angiogenesis. Circ_0008344 functioned as a sponge for miR-638. The negative regulation of circ_0008344 knockdown on glioma progression and angiogenesis could be reversed by miR-638 inhibitor. SZRD1 was a target of miR-318, and its overexpression overturned the inhibition effect of miR-638 mimic on glioma progression and angiogenesis. Meanwhile, we confirmed that circ_0008344 knockdown inhibited SZRD1 expression, and its effect was reversed by miR-638 inhibitor. Also, circ_00008344 knockdown suppressed glioma tumor growth. Circ_0008344 might contribute to glioma progression through miR-638/SZRD1 axis, which might be a novel pathology and treatment target in glioma.

Decreased microRNA-768-3p expression indicates a poor prognosis in patients with breast cancer and promotes breast cancer cell viability, migration and invasion

Breast cancer is the most common malignancy in women and microRNA-768-3p (miR-768-3p) is abnormally expressed in hepatocellular carcinoma, non-small cell lung carcinomas and melanoma. The aim of the present study was to evaluate the prognostic value and biological function of miR-768-3p in breast cancer. The expression of miR-768-3p in tumor tissues and adjacent tissues of 116 patients with breast cancer obtained by surgery and normal breast cell lines MCF-10A and breast cancer cell lines (MCF-7, MDA-MB-231, T-47D and SK-BR-3) were detected by reverse transcription-quantitative PCR. The association between miR-768-3p expression and the clinicopathological characteristics of patients was analyzed using the χ² test. In addition, the Kaplan-Meier method was used for survival analysis. A Cox regression model was used to examine the effect of miR-768-3p on the prognosis of patients with breast cancer. Hemocytometer cell counting and Transwell assays were used to detect the effects of miR-768-3p on the characteristics of breast cancer cells. The target genes of miR-768-3p in breast cancer were identified by bioinformatics software and detected by luciferase reporter assay. Compared with normal tissues and normal breast cancer cells, miR-768-3p was significantly decreased in breast cancer tissues and cancer cells (P<0.001). The reduction in miR-768-3p was significantly associated with lymph node metastasis (P=0.040), Tumor Node Metastasis stage (P=0.035), and cancer subtype (P=0.008). In addition, patients with low miR-768-3p expression had a shorter overall survival time (log-rank P=0.022) compared with those with high expression and miR-768-3p may be a potential prognostic marker (hazard ratio=4.637; 95% confidence interval=1.296-16.597; P=0.018). When transfected with miR-768-3p inhibitor, cell viability, migration and invasion were significantly promoted compared with the control group (P<0.05). In addition, eukaryotic translation initiation factor 4E (eIF4E) was the target gene of miR-768-3p in breast cancer. All experiments confirmed that miR-768-3p, a tumor suppressor, inhibited the viability, migration and invasion of breast cancer cells through eIF4E. miR-768-3p may be a potential prognostic marker of breast cancer and may participate in the progression of breast cancer.