SDF-1α/MicroRNA-134 Axis Regulates Nonfunctioning Pituitary Neuroendocrine Tumor Growth via Targeting VEGFA

Regulatory mechanisms of microRNAs in endocrine disorders and their therapeutic potential

MicroRNAs (miRNAs) are small endogenous non-coding RNA molecules capable of regulating gene expression at the post-transcriptional level either by translational inhibition or mRNA degradation and have recently been importantly related to the diagnosis and prognosis of the most relevant endocrine disorders. The endocrine system comprises various highly vascularized ductless organs regulating metabolism, growth and development, and sexual function. Endocrine disorders constitute the fifth principal cause of death worldwide, and they are considered a significant public health problem due to their long-term effects and negative impact on the patient's quality of life. Over the last few years, miRNAs have been discovered to regulate various biological processes associated with endocrine disorders, which could be advantageous in developing new diagnostic and therapeutic tools. The present review aims to provide an overview of the most recent and significant information regarding the regulatory mechanism of miRNAs during the development of the most relevant endocrine disorders, including diabetes mellitus, thyroid diseases, osteoporosis, pituitary tumors, Cushing's syndrome, adrenal insufficiency and multiple endocrine neoplasia, and their potential implications as disease biomarkers.

Chemokine receptor 7 mediates miRNA-182 to regulate cerebral ischemia/reperfusion injury in rats

AIMS

Chemokine receptor 7 (CXCR7) exerts protective effects on the brain. MicroRNAs (miRNAs) are involved in cerebral ischemia/reperfusion (I/R) injury, but their involvement in CXCR7-mediated brain protection is unknown. In this study, we investigated the role of miRNAs in CXCR7-mediated brain protection.

METHODS

CXCR7 levels in peripheral blood samples from patients with acute ischemic stroke (AIS) and ischemic penumbra area brain tissues from middle cerebral artery occlusion (MCAO) rats after recanalization were measured. An miRNA microarray analysis was performed to examine the expression of miRNAs caused by CXCR7 knockdown in ischemic penumbra area brain tissue in middle cerebral artery occlusion-reperfusion rats and to predict corresponding downstream target genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed the most enriched pathways. A dual-luciferase reporter assay confirmed the direct regulation of miR-182 on the target gene TCF7L2. The correlation between TCF7L2 and CXCR7/miR-182 was verified using rescue assays.

RESULTS

CXCR7 expression was upregulated in MCAO rats and mechanical thrombectomy patients with AIS compared to that in controls. The motor and sensory functions of MCAO rats with CXCR7 knockdown further decreased, and the infarct volume and cerebral edema increased. miRNA microarray data showed that seven miRNAs were differentially expressed after shRNA-CXCR7 treatment. The dual-luciferase reporter assay confirmed that miR-182 directly targeted the TCF7L2 gene. Rescue assays confirmed that TCF7L2 is downstream of CXCR7/miR-182. KEGG pathway analysis showed that the Hippo pathway may be a key pathway in CXCR7 upregulation and plays a role in protecting the brain after interventional surgery. Animal experiments have shown that CXCR7-mediated cerebral I/R injury promotes the phosphorylation of key molecules YAP and TAZ in the Hippo pathway.

CONCLUSION

CXCR7 protects against cerebral I/R injury, possibly via the miR-182/TCF7L2/Hippo pathway. These results indicate that CXCR7 affects cerebral ischemia-reperfusion injury through miRNA regulation and downstream pathways.

A systematic review of molecular alterations in invasive non-functioning pituitary adenoma

PURPOSE

Invasive non-functional pituitary adenomas (NFPAs) constitute 35% of NFPAs. Despite a relatively large body of molecular investigations on the invasiveness of NFPA, the underlying molecular mechanisms of invasiveness are yet to be determined. Herein, we aimed to provide an overview of gene/microRNA(miRNAs) expression alterations in invasive NFPA.

METHODS

This article describes a systematic literature review of articles published up to March 23, 2021, on the transcriptional alterations of invasive NFPA. Five digital libraries were searched, and 42 articles in total fulfilled the eligibility criteria. Pathway enrichment was conducted, and protein interactions among the identified deregulated genes were inferred.

RESULTS

In total 133 gene/protein transcriptional alterations, comprising 87 increased and 46 decreased expressions, were detected in a collective number of 1001 invasive compared with 1007 non-invasive patients with NFPA. Deregulation of CDH1, PTTG1, CCNB1, SNAI1, SLUG, EZR, and PRKACB, which are associated with epidermal-mesenchymal transition (EMT), was identified. Moreover, six members of the angiogenesis pathway, i.e., VEGFA, FLT1, CCND1, CTNNB1, MYC(c-MYC), and PTTG1, were detected. SLC2A1, FLT1, and VEGFA were also recognized in the hypoxia pathway. Physical interactions of CTNNB1 with FLT1, CCND1, and EZR as well as its indirect interactions with VEGFA, MYC, CCNB1, and PCNA indicate the tight interplay between EMT, angiogenesis, and hypoxia pathways in invasive NFPAs. In addition, Hippo, JAK-STAT, MAPK, Wnt, PI3K-Akt, Ras, TGF-b, VEGF, and ErbB were identified as interwoven signaling pathways.

CONCLUSION

In conclusion, invasive NFPA shares very common deregulated signaling pathways with invasive cancers. A large amount of heterogeneity in the reported deregulations in different studies necessitates the validation of the expressional changes of the suggested biomarkers in a large number of patients with invasive NFPA.

A Retrospective Trail Investigating Temozolomide Neoadjuvant Chemotherapy Combined with Radiotherapy in Low-Grade Pituitary Tumors

Objective. To study and analyze the clinical application of temozolomide (TMZ) combined with radiotherapy in the treatment of low-grade pituitary tumors. Methods. A retrospective trail was conducted among 67 patients with low-grade pituitary tumors who were treated in our hospital from March 2018 to June 2020. According to different treatment methods, they were assigned into a combined group (37 cases, temozolomide capsules and radiotherapy) and a control group (30 cases, radiotherapy). The changes of serum prolactin (PRL), insulin-like growth factor-1 (IGF-1), GH levels, thyroid-stimulating hormone (TSH), serum free thyroxine (FT4), and adrenocorticotropic hormone (ACTH) were compared. Results. The chi-square test reports a significantly higher total effective rate in the combined group vs. control group (91.89% vs. 70.00%). Significant reductions in serum levels of PRL, IGF-1, and GH were observed in both groups after treatment, whereas the combined group treated with radiotherapy and TMZ resulted in significantly lower levels compared with the control group ( $p<0.05$ ). After treatment, TSH decreased, and FT4 and ACTH increased in both groups, and the treatment with radiotherapy and TMZ in the combined group led to a significantly greater amplitude of variation ( $p<0.05$ ). Conclusion. The combination of temozolomide and radiotherapy might be a promising technique for the treatment of pituitary tumors, thereby meriting promotion.

The Involvement of miRNAs in Pituitary Adenomas Pathogenesis and the Clinical Implications

Pituitary adenomas (PAs) account for the top three primary intracranial tumors in terms of total incidence rate. PAs can cause severe endocrine disorders and even malignant features, such as invasion, metastasis, and recurrence. Therefore, the early diagnosis and accurate prognosis would be greatly beneficial for clinical treatment of PAs. MicroRNAs (miRNAs) are small, protein-noncoding RNAs that regulate gene expression posttranscriptionally. They regulate essential physiological processes, including proliferation, growth, and apoptosis, and also they involve in the invasion and metastasis of malignant tumors. At the tissue level, differential miRNA expression in endocrine malignancies including PAs has been reported. When miRNAs have been successfully detected in various biofluids and cell-free environments, their important roles as potential screening or prognostic biomarkers have been extensively investigated. The current work reviews recent studies on the emerging roles of miRNAs in PAs and the clinical significance.

The Emerging Role of Non-Coding RNAs in Pituitary Gland Tumors and Meningioma

Long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs) are non-coding transcripts which are involved in the pathogenesis of pituitary gland tumors. LncRNAs that participate in the pathogenesis of pituitary gland tumors mainly serve as sponges for miRNAs. CLRN1-AS1/miR-217, XIST/miR-424-5p, H19/miR-93a, LINC00473/miR-502-3p, SNHG7/miR-449a, MEG8/miR-454-3p, MEG3/miR-23b-3p, MEG3/miR-376B-3P, SNHG6/miR-944, PCAT6/miR-139-3p, lncRNA-m433s1/miR-433, TUG1/miR-187-3p, SNHG1/miR-187-3p, SNHG1/miR-302, SNHG1/miR-372, SNHG1/miR-373, and SNHG1/miR-520 are identified lncRNA/miRNA pairs that are involved in this process. Hsa_circ_0001368 and circOMA1 are two examples of circRNAs that contribute to the pathogenesis of pituitary gland tumors. Meanwhile, SNHG1, LINC00702, LINC00460, and MEG3 have been found to partake in the pathogenesis of meningioma. In the current review, we describe the role of non-coding RNAs in two types of brain tumors, i.e., pituitary tumors and meningioma.