Circular RNA circWDR27 Promotes Papillary Thyroid Cancer Progression by Regulating miR-215-5p/TRIM44 Axis

Intricate confrontation: Research progress and application potential of TRIM family proteins in tumor immune escape

BACKGROUND

Tripartite motif (TRIM) family proteins have more than 80 members and are widely found in various eukaryotic cells. Most TRIM family proteins participate in the ubiquitin-proteasome degradation system as E3-ubiquitin ligases; therefore, they play pivotal regulatory roles in the occurrence and development of tumors, including tumor immune escape. Due to the diversity of functional domains of TRIM family proteins, they can extensively participate in multiple signaling pathways of tumor immune escape through different substrates. In current research and clinical contexts, immune escape has become an urgent problem. The extensive participation of TRIM family proteins in curing tumors or preventing postoperative recurrence and metastasis makes them promising targets.

AIM OF REVIEW

The aim of the review is to make up for the gap in the current research on TRIM family proteins and tumor immune escape and propose future development directions according to the current progress and problems.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This up-to-date review summarizes the characteristics and biological functions of TRIM family proteins, discusses the mechanisms of TRIM family proteins involved in tumor immune escape, and highlights the specific mechanism from the level of structure-function-molecule-pathway-phenotype, including mechanisms at the level of protein domains and functions, at the level of molecules and signaling pathways, and at the level of cells and microenvironments. We also discuss the application potential of TRIM family proteins in tumor immunotherapy, such as possible treatment strategies for combination targeting TRIM family protein drugs and checkpoint inhibitors for improving cancer treatment.

The Emerging Roles of circRNAs in Papillary Thyroid Carcinoma: Molecular Mechanisms and Biomarker Potential

Papillary thyroid carcinoma (PTC) is a common endocrine malignant tumor. The incidence of PTC has increased in the past decades and presents a younger trend. Accumulating evidence indicates that circular RNAs (circRNAs), featured with non-linear, closed-loop structures, play pivotal roles in tumorigenesis and regulate cell biological processes, such as proliferation, migration, and invasion, by acting as microRNA (miRNA) sponges. Additionally, due to their unique stability, circRNAs hold promising potential as diagnostic biomarkers and effective therapeutic targets for PTC treatment. In this review, we systematically arrange the expression level of circRNAs, related clinical characteristics, circRNA-miRNA-mRNA regulatory network, and molecular mechanisms. Furthermore, related signaling pathways and their potential ability of diagnostic biomarkers and therapeutic targets are discussed, which might provide a new strategy for PTC diagnosis, monitoring, and prognosis.

miR-21-5p Inhibits Ferroptosis in Hepatocellular Carcinoma Cells by Regulating the AKT/mTOR Signaling Pathway through MELK

Background

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers, and its incidence rate is increasing worldwide. At present, there is no ideal treatment for HCC. In recent years, molecular-targeted therapy has shown significant therapeutic benefits for patients. Ferroptosis is a modality of regulated cell death, and previous studies have found that inducing ferroptosis in liver cancer cells can inhibit the progression of liver cancer. The aim of this study is to investigate the regulatory mechanism of miR-21-5p in regulating ferroptosis in HCC cells.

Methods

CCK-8 was used to measure cell viability, EdU and colony formation were used to measure cell proliferation, and Transwell assays were used to measure cell migration and invasion. RT-qPCR was used to detect the level of miR-21-5p, Western blotting was used to detect the protein expression level, a dual-luciferase reporter gene assay was used to determine the targeting relationship between miR-21-5p and MELK, and coimmunoprecipitation was used to determine the interaction between MELK and AKT.

Results

Overexpression of miR-21-5p and MELK facilitated the viability, proliferation, colony formation, invasion, and migration of HCC cells. Downregulation of miR-21-5p suppressed the level of MELK and the progression of HCC. MELK regulated the AKT/mTOR signaling pathway, causing changes in the levels of GPX4, GSH, FTH1, xCT, heme oxygenase 1(HO-1), reactive oxygen species, and Fe²⁺ to regulate the ferroptosis of hepatoma cells. Erastin, an inducer of ferroptosis, attenuated the repressive influence of miR-21-5p on ferroptosis in HCC cells.

Conclusion

In summary, this study demonstrates that miR-21-5p inhibits the ferroptosis of HCC cells by regulating the AKT/mTOR signaling pathway through MELK.

miR-215-5p regulates osteoporosis development and osteogenic differentiation by targeting XIAP

Background

Osteoporosis (OP) is a metabolic disease that involves microstructure destruction and fracture damage. The present study probed into the significance of miR-215-5p in OP progression.

Methods

Serum samples were collected from surgical patients and healthy controls. qRT-PCR analysis was utilized to determine the miR-215-5p level in clinical samples and human bone mesenchymal stem cells (hBMSCs) induced by β-glycerol phosphate. A dual luciferase reporter assay was exploited to examine the targeted relationship between miR-215-5p and XIAP. The mineralization and calcium deposition of hBMSCs were assessed by detection of ALP activity, Alizarin red staining, and osteoblast marker expression. Protein expression was determined by western blot analysis.

Results

MiR-215-5p was significantly reduced in patients with OP and increased in hBMSCs treated with β-glycerophosphate. Enhanced miR-215-5p level triggered augment in osteoblast markers (Alkaline phosphatase/ ALP, Osteocalcin/ OCN, and Runt-Related Transcription Factor 2/ Runx2), which was accompanied by the increase of ALP activity in hBMSCs and accumulation of Calcium. Functional experiments show that XIAP was a target of miR-215-5p and negatively modulated by miR-215-5p. XIAP expression levels were increased in OP samples, and decreased XIAP in β-glycerophosphate-treated hBMSCs inhibited its’ osteogenic differentiation. Functional loss and acquisition experiments depicted that miR-215-5p promoted the differentiation of hBMSCs by inhibiting the XIAP level, playing a protective role in the pathogenesis of OP.

Conclusions

β-glycerophosphate promoted the osteogenic differentiation of hBMSCs, increased miR-215-5p level, and decreased XIAP. miR-215-5p stimulated osteogenic differentiation of hBMSCs by targeting XIAP, shedding new insights for the detection and therapy of OP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05731-w.

Function and Clinical Significance of Circular RNAs in Thyroid Cancer

Thyroid cancer (TC) is the leading cause and mortality of endocrine malignancies worldwide. Tumourigenesis involves multiple molecules including circular RNAs (circRNAs). circRNAs with covalently closed single-stranded structures have been identified as a type of regulatory RNA because of their high stability, abundance, and tissue/developmental stage-specific expression. Accumulating evidence has demonstrated that various circRNAs are aberrantly expressed in thyroid tissues, cells, exosomes, and body fluids in patients with TC. CircRNAs have been identified as either oncogenic or tumour suppressor roles in regulating tumourigenesis, tumour metabolism, metastasis, ferroptosis, and chemoradiation resistance in TC. Importantly, circRNAs exert pivotal effects on TC through various mechanisms, including acting as miRNA sponges or decoys, interacting with RNA-binding proteins, and translating functional peptides. Recent studies have suggested that many different circRNAs are associated with certain clinicopathological features, implying that the altered expression of circRNAs may be characteristic of TC. The purpose of this review is to provide an overview of recent advances on the dysregulation, functions, molecular mechanisms and potential clinical applications of circRNAs in TC. This review also aimes to improve our understanding of the functions of circRNAs in the initiation and progression of cancer, and to discuss the future perspectives on strategies targeting circRNAs in TC.

MicroRNAs as the critical regulators of cell migration and invasion in thyroid cancer

Thyroid cancer (TC) is one of the most frequent endocrine malignancies that is more common among females. Tumor recurrence is one of the most important clinical manifestations in differentiated TC which is associated with different factors including age, tumor size, and histological features. Various molecular processes such as genetic or epigenetic modifications and non-coding RNAs are also involved in TC progression and metastasis. The epithelial-to-mesenchymal transition (EMT) is an important biological process during tumor invasion and migration that affects the initiation and transformation of early-stage tumors into invasive malignancies. A combination of transcription factors, growth factors, signaling pathways, and epigenetic regulations affect the thyroid cell migration and EMT process. MicroRNAs (miRNAs) are important molecular factors involved in tumor metastasis by regulation of EMT-activating signaling pathways. Various miRNAs are involved in the signaling pathways associated with TC metastasis which can be used as diagnostic and therapeutic biomarkers. Since, the miRNAs are sensitive, specific, and non-invasive, they can be suggested as efficient and optimal biomarkers of tumor invasion and metastasis. In the present review, we have summarized all of the miRNAs which have been significantly involved in thyroid tumor cells migration and invasion. We also categorized all of the reported miRNAs based on their cellular processes to clarify the molecular role of miRNAs during thyroid tumor cell migration and invasion. This review paves the way of introducing a non-invasive diagnostic and prognostic panel of miRNAs in aggressive and metastatic TC patients.

Exosomal circular RNA hsa_circ_007293 promotes proliferation, migration, invasion, and epithelial-mesenchymal transition of papillary thyroid carcinoma cells through regulation of the microRNA-653-5p/paired box 6 axis

Circular RNAs (circRNAs) or exosomes have been reported to exert key regulatory and/or communication functions in human cancer. Nevertheless, current literature on the effects of exosomal circRNAs on tumor invasion and metastasis in thyroid cancer is incomplete. The role of tumor-derived exosomes in driving in vitro papillary thyroid carcinoma (PTC) progression and metastasis requires further investigation. In our study, Exosomes were harvested from PTC patient serum and PTC cell culture medium. Gene expression analysis in PTC cell lines and exosomes was performed with quantitative reverse-transcription polymerase chain reaction. Transwell, wound healing, Western blot assays, and the cell counting kit-8 were applied for functional analysis. Dual-luciferase reporter assay was used to examine the interaction between hsa_circ_007293 (circ007293), microRNA (miR)-653-5p, and paired box 6 (PAX6). Results showed that circ007293 was enriched in exosomes derived from PTC patient serum and cell culture media. Moreover, circ007293 could enter PTC cells through exosomes, and exosomal circ007293 promoted PTC cell epithelial-mesenchymal transition, invasion, migration, and proliferation. circ007293 knockdown reversed the malignant phenotype of PTC cells in vitro. Additionally, circ007293 could competitively bind with miR-653-5p to regulate PAX6 expression. Notably, miR-653-5p overexpression or PAX6 inhibition suppressed the malignant effects of exosomal circ007293. These results evidenced that exosomal circ007293 induced EMT and augmented the invasive and migratory abilities of PTC cells via the miR-653-5p/PAX6 axis, suggesting that it may serve as a promising biomarker for cancer progression.

TRIM proteins in fibrosis

Fibrosis is an outcome of tissue repair after different types of injuries. The homeostasis of extracellular matrix is broken, and excessive deposition occurs, affecting the normal function of tissues and organs, which could become prostrated in serious cases.Finding a suitable target to regulate the repair process and reduce the damage caused by fibrosis is a hot research topic at present. The TRIM family is number of one of the E3 ubiquitin ligase subfamilies and participates in various biological processes including intracellular signal transduction, apoptosis, autophagy, and immunity by regulating the ubiquitination of target proteins. For the past few years, the important role of TRIM in the occurrence and development of fibrosis has been gradually revealed. In this review, we focus on the recent emerging topics on TRIM proteins in the regulation of fibrosis, fibrosis-related cytokines and pathways.