MicroRNA-101 Targets CXCL12-Mediated Akt and Snail Signaling Pathways to Inhibit Cellular Proliferation and Invasion in Papillary Thyroid Carcinoma

Profile of MicroRNAs Associated with Death Due to Disease Progression in Metastatic Papillary Thyroid Carcinoma Patients

Papillary thyroid carcinoma (PTC) is the most common neoplasm of the endocrine system and has an excellent long-term prognosis, with low rates of distant metastatic disease. Although infrequent, there are cases of deaths directly related to PTC, especially in patients with metastatic disease, and the factors that could be associated with this unfavorable outcome remain a major challenge in clinical practice. Recently, research into genetic factors associated with PTC has gained ground, especially mutations in the TERT promoter and BRAF gene. However, the role of microRNAs remains poorly studied, especially in those patients who have an unfavorable outcome at follow-up. This paper aims to evaluate molecular markers related to the different pathological processes of PTC, as well as the histological characteristics of the neoplasm, and to compare this profile with prognosis and death from the disease using an analysis of patients treated for metastatic disease in a single tertiary cancer center. Evaluation of microRNA expression in paraffin-embedded tumor specimens was carried out by quantitative PCR using the TaqMan® Low Density Array (TLDA) system. Metastatic patients who died from progression of PTC had higher expressions of miR-101-3p, miR-17-5p, and miR-191-5p when compared to patients with stable metastatic disease. These findings are of great importance but should be considered as preliminary because of the small sample.

MiR-101: An Important Regulator of Gene Expression and Tumor Ecosystem

MiRNAs are small single-stranded non-coding RNAs. MiRNA contributes to the transcriptional and post-transcriptional regulation of mRNA in different cell types, including mRNA transcription inhibition and mRNA decay and phenotypes via the effect of several essential oncogenic processes and tumor microenvironment. MiR-101 is a highly conserved miRNA that was found to alter the expression in various human cancers. MiR-101 has been reported to have tumor oncogenic and suppressive effects to regulate tumorigenesis and tumor progression. In this review, we summarize the new findings about the roles of miR-101 in cancers and the underlying mechanisms of targeting genes degradation and microenvironment regulation, which will improve biological understanding and design of novel therapeutics.

EMT in salivary gland tumors: the expression of microRNAs miR-155 and miR-200c is associated with clinical-pathological parameters

BACKGROUND

Epithelial to mesenchymal transition promotes cell adhesion loss, enabling invasion and metastasis. MicroRNAs are a class of small non-codifying RNAs that regulate gene expression.

OBJECTIVES

The aim of this study was to evaluate the expression of microRNAs that could regulate the expression of EMT factors in salivary gland tumors (SGTs).

METHODS AND RESULTS

The expression of microRNAs miR-9, miR-34a, miR-101, miR-138, miR-155, and miR-200c-described in the literature to target EMT factors-was evaluated by Real-time RT-PCR (qPCR) in pleomorphic adenoma (PA), mucoepidermoid carcinoma (MEC) and adenoid cystic carcinoma (ACC) samples. Bioinformatics tools were applied to identify miR targets and immunohistochemistry was used to examine the expression of the proteins E-cadherin, Twist, ZEB-1, β-Catenin, and c-Kit. Comparing miR expression among SGT types, we observed increased expression of miR-9, and miR-138 in PAs, and increased miR-155 expression in MECs. Low-grade MECs exhibited increased miR-155 expression (p = 0.032). MECs that generated lymph node metastases had increased miR-200c levels (p = 0.018). MECs tended to have decreased expression of EMT-related proteins when compared to the other SGT types (c-Kit p < 0.001, Twist p = 0.014, and ZEB p = 0.012). Notably, increased c-Kit expression was associated with the presence of perineural infiltration in ACC (p = 0.050).

CONCLUSIONS

This study provides evidence of alterations in the expression of EMT-factors regulating miRs, especially of miR-9, miR-138, miR-155, and miR-200c. No significant relationships were found between the expression of these miRs and proteins associated with EMT in SGTs.

Research trends in pharmacological modulation of tumor-associated macrophages

As one of the most abundant immune cell populations in the tumor microenvironment (TME), tumor-associated macrophages (TAMs) play important roles in multiple solid malignancies, including breast cancer, prostate cancer, liver cancer, lung cancer, ovarian cancer, gastric cancer, pancreatic cancer, and colorectal cancer. TAMs could contribute to carcinogenesis, neoangiogenesis, immune-suppressive TME remodeling, cancer chemoresistance, recurrence, and metastasis. Therefore, reprogramming of the immune-suppressive TAMs by pharmacological approaches has attracted considerable research attention in recent years. In this review, the promising pharmaceutical targets, as well as the existing modulatory strategies of TAMs were summarized. The chemokine-chemokine receptor signaling, tyrosine kinase receptor signaling, metabolic signaling, and exosomal signaling have been highlighted in determining the biological functions of TAMs. Besides, both preclinical research and clinical trials have suggested the chemokine-chemokine receptor blockers, tyrosine kinase inhibitors, bisphosphonates, as well as the exosomal or nanoparticle-based targeting delivery systems as the promising pharmacological approaches for TAMs deletion or reprogramming. Lastly, the combined therapies of TAMs-targeting strategies with traditional treatments or immunotherapies as well as the exosome-like nanovesicles for cancer therapy are prospected.

MicroRNA in Papillary Thyroid Carcinoma: A Systematic Review from 2018 to June 2020

Simple Summary

The most common form of endocrine cancer - papillary thyroid carcinoma, has an increasing incidence. Although this disease usually has an indolent behavior, there are cases when it can evolve more aggressively. It has been known for some time that it is possible to use microRNAs for the diagnosis, prognosis and even treatment monitoring of papillary thyroid cancer. The purpose of this study is to summarize the latest information provided by publications regarding the involvement of microRNAs in papillary thyroid cancer, underling the new clinical perspectives offered by these publications.

Abstract

The involvement of micro-ribonucleic acid (microRNAs) in metabolic pathways such as regulation, signal transduction, cell maintenance, and differentiation make them possible biomarkers and therapeutic targets. The purpose of this review is to summarize the information published in the last two and a half years about the involvement of microRNAs in papillary thyroid carcinoma (PTC). Another goal is to understand the perspective offered by the new findings. Main microRNA features such as origin, regulation, targeted genes, and metabolic pathways will be presented in this paper. We interrogated the PubMed database using several keywords: “microRNA” + “thyroid” + “papillary” + “carcinoma”. After applying search filters and inclusion criteria, a selection of 137 articles published between January 2018–June 2020 was made. Data regarding microRNA, metabolic pathways, gene/protein, and study utility were selected and included in the table and later discussed regarding the matter at hand. We found that most microRNAs regularly expressed in the normal thyroid gland are downregulated in PTC, indicating an important tumor-suppressor action by those microRNAs. Moreover, we showed that one gene can be targeted by several microRNAs and have nominally described these interactions. We have revealed which microRNAs can target several genes at once.

Docosahexaenoic acid (DHA) inhibits pro-angiogenic effects of breast cancer cells via down-regulating cellular and exosomal expression of angiogenic genes and microRNAs

AIMS

Docosahexaenoic acid (DHA) as an omega 3 free fatty acid has been reported to exert anti-angiogenesis effects. However, our current understanding regarding the precise mechanisms of such effects is still limited. Exosomes secreted by cancer cells may act as angiogenesis promoters. The aim of the study was to determine altered expression levels of HIF-1α, TGF-β, VEGFR, Snail1, Snail2 and SOX2 and their regulating microRNAs in MDA-MB-231 and BT-474 cell lines after treatment with DHA in both normoxic and hypoxic conditions.

MAIN METHODS

Human breast cancer cell lines including MDA-MB-231 and BT-474 were treated for 24 h with 100 uM DHA under normoxic and hypoxic conditions. Exosomes were isolated from untreated and treated cells and characterized by transmission electron microscopy (TEM) and western blotting. RNAs from cells and isolated exosomes were extracted and cDNAs were synthesized. Expression levels of miRNAs and their pro-angiogenic target genes were analyzed using quantitative real-time PCR (qRT-PCR).

KEY FINDINGS

We showed significant decrease in the expression of pro-angiogenic genes including HIF1-α, TGF-β, SOX2, Snail1, Snail2 and VEGFR in cells and also their secreted exosomes after treatment with DHA in normoxic and hypoxic conditions. Also the expression levels of tumor suppressor miRs including miR-101, miR-199, miR-342 were increased and the expression levels of oncomiRs including mir-382 and miR-21 were decreased after treatment with DHA in cells and exosomes.

SIGNIFICANCE

DHA can alter the expression of pro-angiogenic genes and microRNA contents in breast cancer cells and their derived-exosomes in favor of the inhibition of angiogenesis. Our data demonstrated new insight into DHA's anti-cancer action to target not only breast cancer cells but also their derived exosomes to suppress tumor angiogenesis.

Interplay among SNAIL Transcription Factor, MicroRNAs, Long Non-Coding RNAs, and Circular RNAs in the Regulation of Tumor Growth and Metastasis

SNAIL (SNAI1) is a zinc finger transcription factor that binds to E-box sequences and regulates the expression of genes. It usually acts as a gene repressor, but it may also activate the expression of genes. SNAIL plays a key role in the regulation of epithelial to mesenchymal transition, which is the main mechanism responsible for the progression and metastasis of epithelial tumors. Nevertheless, it also regulates different processes that are responsible for tumor growth, such as the activity of cancer stem cells, the control of cell metabolism, and the regulation of differentiation. Different proteins and microRNAs may regulate the SNAIL level, and SNAIL may be an important regulator of microRNA expression as well. The interplay among SNAIL, microRNAs, long non-coding RNAs, and circular RNAs is a key event in the regulation of tumor growth and metastasis. This review for the first time discusses different types of regulation between SNAIL and non-coding RNAs with a focus on feedback loops and the role of competitive RNA. Understanding these mechanisms may help develop novel therapeutic strategies against cancer based on microRNAs.