MiRNA-16 inhibited oral squamous carcinoma tumor growth in vitro and in vivo via suppressing Wnt/β-catenin signaling pathway

Review of Disease-Specific microRNAs by Strategically Bridging Genetics and Epigenetics in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most prevalent human malignancies and a global health concern with a poor prognosis despite some therapeutic advances, highlighting the need for a better understanding of its molecular etiology. The genomic landscape of OSCC is well-established and recent research has focused on miRNAs, which regulate gene expression and may be useful non-invasive biomarkers or therapeutic targets. A plethora of findings regarding miRNA expression have been generated, posing challenges for the interpretation and identification of disease-specific molecules. Hence, we opted to identify the most important regulatory miRNAs by bridging genetics and epigenetics, focusing on the key genes implicated in OSCC development. Based on published reports, we have developed custom panels of fifteen major oncogenes and five major tumor suppressor genes. Following a miRNA/target gene interaction analysis and a comprehensive study of the literature, we selected the miRNA molecules which target the majority of these panels that have been reported to be downregulated or upregulated in OSCC, respectively. As a result, miR-34a-5p, miR-155-5p, miR-124-3p, miR-1-3p, and miR-16-5p appeared to be the most OSCC-specific. Their expression patterns, verified targets, and the signaling pathways affected by their dysregulation in OSCC are thoroughly discussed.

Salivary miR-30c-5p as Potential Biomarker for Detection of Oral Squamous Cell Carcinoma

The levels of different classes of extracellular RNAs (exRNAs) remain stable in bodily fluids. The detection of either enriched or depleted specific subsets of salivary microRNAs (miRNAs) has the potential to serve as a non-invasive approach for biomarker development. Thus, salivary miRNAs have emerged as a promising molecular tool for early diagnosis and screening of oral squamous cell carcinoma (OSCC). Total RNA was extracted from saliva supernatant of 33 OSCC patients and 12 controls (discovery set), and the differential expression of 8 cancer-related miRNAs was detected by TaqMan assay. Among the screened miRNAs, miR-30c-5p (p < 0.04) was significantly decreased in OSCC saliva. The same transcriptional behavior of miR30c-5p was observed in an additional validation set. miR-30c-5p showed a significant statistical difference between cases and controls with areas under the curve (AUC) of 0.82 (95% CI: 0.71–0.89). The sensitivity and the specificity of miR-30c-5p were 86% and 74%, respectively. The target identification analysis revealed enrichment of miR-30c-5p targets in p53 and Wnt signaling pathways in OSCC. Additionally, the miR-30c-5p targets had clinical significance related to overall survival. In conclusion, these findings show that downregulated miR-30c-5p has the potential to serve as a novel, non-invasive biomarker for early OSCC detection.

LINC00662 Promotes Oral Squamous Cell Carcinoma Cell Growth and Metastasis through miR-144-3p/EZH2 Axis

PURPOSE

Long non-coding RNA (lncRNA) is identified as an important regulator involved in oral squamous cell carcinoma (OSCC) tumorigenesis. This study aimed to investigate the functional role and underlying mechanism of LINC00662 in OSCC.

MATERIALS AND METHODS

The expression levels of LINC00662, miR-144-3p, and enhancer of zeste homolog 2 (EZH2) mRNA were quantified with quantitative real-time polymerase chain reaction in OSCC tissues and cell lines. Western blot analysis was used to assay the expression levels of E-cadherin, Vimentin, and EZH2. Cell proliferation, migration, and invasion were monitored by cell counting kit-8 and Transwell assays. Dual-luciferase reporter and RNA immunoprecipitation assays were employed to verify the regulatory relationship between LINC00662 and miR-144-3p.

RESULTS

The expression of LINC00662, positively associated with the increased TNM stage and lymph node metastasis of the patients, was up-regulated in OSCC tissues and cells. The overexpression of LINC00662 facilitated the proliferation, migration, and invasion of OSCC cells. MiR-144-3p could bind to LINC00662, and the promoting effect of LINC00662 overexpression was counteracted by miR-144-3p mimic. Moreover, EZH2 expression was negatively regulated by miR-144-3p and positively regulated by LINC00662. The silencing of EZH2 attenuated the promoting effects of overexpression of LINC00662 on cell proliferation, migration, invasion, and epithelial-mesenchymal transition.

CONCLUSION

LINC00662, as an oncogenic lncRNA of OSCC, accelerates OSCC progression by repressing miR-144-3p expression and increasing EZH2 expression.

Regulatory Role of microRNAs in Tumor Angiogenesis

The process of neoangiogenesis is one of the classic hallmarks of a cancer. Its intricate mechanisms have long been one of the major domains in cancer research and a hope for a therapeutic breakthrough. Last decade a new subgroup of non-coding RNA molecules was reported called microRNAs. Literally hundreds of new molecules in this class are being uncovered as pivotal regulators in virtually all intracellular processes. The aim of this study is to classify and review those microRNA molecules that have a role in the processes of tumor angiogenesis and map their places in the regulatory framework of the classical proangiogenic genes and their canonical cascades.

LncRNA MORT Inhibits Cancer Cell Proliferation and Promotes Apoptosis in Mantle Cell Lymphoma by Upregulating miRNA-16

Introduction

LncRNA mortal obligate RNA transcript (MORT) is downregulated in different types of cancer, indicating its involvement in cancer biology.

Methods

In this study, MORT and miRNA-16 were both downregulated in plasma of mantle cell lymphoma (MCL) patients than that in the controls. The low levels of MORT and miRNA-16 were correlated with poor survival of MCL patients. The expression of MORT and miRNA-16 was positively correlated only in MCL patients.

Results

Overexpression of MORT and miRNA-16 suppressed cell proliferation but promoted cancer cell apoptosis, while miRNA-16 inhibitor reduced the effects of MORT overexpression. Overexpression of MORT led to upregulated expression of miRNA-16, while overexpression of miRNA-16 had no effect on the expression of MORT.

Conclusion

Therefore, MORT may inhibit cancer cell proliferation and promote apoptosis in mantle cell lymphoma by upregulating miRNA-16.

miR-16 enhances miR-302/367-induced reprogramming and tumor suppression in breast cancer cells

Overexpression of either miR-302 or miR-302/367 cluster induces reprogramming of cancer cells and exerts tumor-suppressive effects by induction of mesenchymal-to-epithelial transition, apoptosis and a less proliferative capacity. Several reports have described miR-16 as a tumor suppressor microRNA (miRNA). Here, we studied the impact of exogenous induction of miR-16 in MDA-MB-231 and SK-BR-3 breast cancer cells following overexpression of miR-302/367 cluster and investigated whether transfection of these cells by a mature miR-16 mimic could affect the reprogramming state of the cells and their tumorigenicity. miR-16 enhanced the expression levels of OCT4A, SOX2, and NANOG, generally known as transcription or pluripotency factors, and suppressed proliferation and invasiveness of these cells. Meanwhile, inhibition of miR-16 counteracted both the reprogramming effect and the antitumor function of miR-302/367 in the breast cancer cells. Current results indicate that miR-16 can work as an adjuvant to improve both cancer cell reprogramming and tumor-suppressive function of miR-302/367 cluster in MDA-MB-231 and SK-BR-3 cells, while its inhibition counteracts all of these effects. Combined application of miRNAs that share some common targets in cancer cell signaling pathways may provide new approaches for repression of multiple hallmarks of cancer.

The role and mechanism of microRNA‑18a‑5p in oral squamous cell carcinoma

The purpose of this study was mainly to explore the role and mechanism of microRNA-18a-5p (miR-18a-5p) in oral squamous cell carcinoma (OSCC). The expression of miR-18a-5p in OSCC cells and normal cells was firstly detected using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The cell viability, apoptosis, migration and invasion abilities of OSCC cells were determined by MTT, cell apoptosis, wound healing and Transwell assays respectively. Additionally, bioinformatics software analysis and luciferase reporter assays were performed to predict and confirm the candidate target of miR-18a-5p. Western blot analysis was used to assess protein expression. It was revealed that the expression of miR-18a-5p in OSCC cells was higher than that in normal cells. In vitro studies revealed that the cell viability, migration and invasion abilities of OSCC cells were promoted and cell apoptosis was inhibited by miR-18a-5p overexpression. In addition, Smad2 was identified as a target of miR-18a-5p. It was also revealed that miR-18a-5p overexpression significantly inhibited the expression of Smad2, Smad4 and E-cadherin, and the levels of Smad7, collagen I, transforming growth factor-β (TGF-β), α-smooth muscle actin (α-SMA), vimentin were enhanced. While miR-18a-5p downregulation presented the opposite effects. In conclusion, the results indicated that miR-18a-5p can regulate the biological process of OSCC by targeting Smad2 and miR-18a-5p/Smad2 may be potential therapeutic targets for OSCC.

HMGA2 regulates acute myeloid leukemia progression and sensitivity to daunorubicin via Wnt/β-catenin signaling

Acute myeloid leukemia (AML) is a malignant disease with an increasing prevalence in adults and children. However, valuable molecular diagnostic research is rare. In the present study, plasmids silencing and overexpressing high‑mobility group AT‑hook 2 (HMGA2) were respectively transfected in HL60 and NB4 cells. The effects of HMGA2 on AML cell viability, apoptosis, migration and invasion were determined by preforming MTT, flow cytometry, wound scratch and Transwell assays, respectively. Genes associated with apoptosis and Wnt signaling were evaluated by reverse transcription‑quantitative (RT‑q)‑PCR and western blotting. AML cell sensitivity to daunorubicin (DNR) and the regulatory effects of the Wnt signaling pathway via HMGA2 following treatment with the agonist LiCl or antagonist XAV939 were detected by MTT, RT‑qPCR and western blot analysis. The results revealed that the expression of HMGA2 was elevated more so in HL60, KG1, U937, Kasumi‑1, THP‑1 and K562 cells than in NB4 cells. Silencing HMGA2 suppressed cell viability, migration and invasion, enhanced cell apoptosis and sensitivity to DNR, and almost restored the DNR inhibitory function that was promoted by LiCl treatment. In addition, low expression of HMGA2 attenuated X‑linked inhibitor of apoptosis and Bcl‑2 mRNA and protein levels, and upregulated the expression of Bax and cleaved‑caspase‑3. Furthermore, silencing HMGA2 not only decreased Wnt and non‑phospho‑β‑catenin expressions, but also partially reversed the increased expressions of these proteins induced by LiCl treatment. On the other hand, overexpression of HMGA2 exhibited the opposite results after transfection in NB4 cells. The results of the present study demonstrated that HMGA2 played important roles in driving AML progression and chemosensitivity in HL60 and NB4 cells, potentially by activating the Wnt/β‑catenin signaling pathway. Therefore, it was suggested that HMGA2 may be a promising molecular marker for AML diagnosis.