miR-422a is an independent prognostic factor and functions as a potential tumor suppressor in colorectal cancer

Integrated analysis using ToppMiR uncovers altered miRNA- mRNA regulatory networks in pediatric hepatocellular carcinoma-A pilot study

BACKGROUND

Pediatric hepatocellular carcinoma (HCC) is a group of liver cancers whose mechanisms behind their pathogenesis and progression are poorly understood.

AIM

We aimed to identify alterations in the expression of miRNAs and their putative target mRNAs in not only tumor tissues of patients with pediatric HCC but also in corresponding non-tumorous background livers by using liver tissues without underlying liver disease as a control.

METHODS AND RESULTS

We performed a small-scale miRNA and mRNA profiling of pediatric HCC (consisting of fibrolamellar carcinoma [FLC] and non-FLC HCC) and paired liver tissues to identify miRNAs whose expression levels differed significantly from control livers without underlying liver disease. ToppMiR was used to prioritize both miRNAs and their putative target mRNAs in a gene-annotation network, and the mRNA profile was used to refine the prioritization. Our analysis generated prioritized lists of miRNAs and mRNAs from the following three sets of analyses: (a) pediatric HCC versus control; (b) FLC versus control; and (c) corresponding non-tumorous background liver tissues from the same patients with pediatric HCC versus control. No liver disease liver tissues were used as the control group for all analyses. Many miRNAs whose expressions were deregulated in pediatric HCC were consistent with their roles in adult HCC and/or other non-hepatic cancers. Our gene ontology analysis of target mRNAs revealed enrichment of biological processes related to the sustenance and propagation of cancer and significant downregulation of metabolic processes.

CONCLUSION

Our pilot study indicates that alterations in miRNA-mRNA networks were detected in not only tumor tissues but also corresponding non-tumorous liver tissues from patients with pediatric HCC, suggesting multi-faceted roles of miRNAs in disease progression. Our results may lead to novel hypotheses for future large-scale studies.

The role of miR-370 and miR-138 in the regulation of BMP2 suppressor gene expression in colorectal cancer: preliminary studies

PURPOSE

Colorectal cancer (CRC) is the fourth-most common cancer worldwide and the second most common cancer cause of death in the world. The components of the TGFβ-signalling pathway, which are often affected by miRNAs, are involved in the regulation of apoptosis and cell cycle. Therefore, in the current study, the expression of BMP2 gene in CRC tissues at different clinical stages compared to the non-tumour tissues has been assessed. Moreover, the plasma BMP2 protein concentration in the same group of CRC patients has been validated. Due to the constant necessity to conduct further research of the correlation between specific miRNAs and mRNAs in CRC, in silico analysis has been performed to select miRNAs that regulate BMP2 mRNA.

METHODS

The cDNA samples from tumor and non-tumor tissue were used in a qPCR reaction to determine the mRNA expression of the BMP2 gene and the expression of selected miRNAs. The concentration of BMP2 protein in plasma samples was also measured.

RESULTS

It was indicated that BMP2 was downregulated in CRC tissue. Moreover, miR-370 and miR-138 expression showed an upward trend. Decreased BMP2 with accompanied increasing miR-370 and miR-138 expression was relevant to the malignant clinicopathological features of CRC and consequently poor patient prognosis.

CONCLUSION

Our data suggest that miR-370 with its clear expression in plasma samples may be a potential diagnostic marker to determine the severity of the disease in patients at a later stage of colorectal cancer.

Downregulation of long non‑coding RNA GACAT1 suppresses proliferation and induces apoptosis of NSCLC cells by sponging microRNA‑422a

Increasing evidence has demonstrated the important roles of long non‑coding (lnc) RNA in non‑small cell lung cancer (NSCLC). lncRNA gastric cancer‑associated transcript 1 (GACAT1) has been reported to play an oncogenic role in different types of cancer; however, the function of GACAT1 in NSCLC remains unclear. The present study found that GACAT1 was overexpressed in NSCLC tissues and was associated with poor outcomes in patients with NSCLC. Functional experiments revealed that GACAT1 downregulation inhibited proliferation, induced apoptosis and cell cycle arrest of 2 NSCLC cell lines. GACAT1 was found to target microRNA(miR)‑422a mechanically and negatively regulated miR‑422a expression. Reduced expression of miR‑422a in NSCLC tissues was inversely correlated with that of GACAT1. Furthermore, YY1 transcription factor (YY1) was identified as a downstream miR‑422a target. Reduced expression of GACAT1 inactivated YY1 by sponging miR‑422a in NSCLC cells. YY1 reintroduction reversed the reduced proliferation of NSCLC cells via GACAT1 knockdown. Taken together, these results revealed the novel role of the GACAT1/miR‑422a pathway in the progression of NSCLC cell lines, providing a possible therapeutic strategy for NSCLC treatment.

Knockdown of circular RNA UBAP2 inhibits the malignant behaviours of esophageal squamous cell carcinoma by microRNA-422a/Rab10 axis

Esophageal squamous cell carcinoma (ESCC) is a major type of esophageal cancer, accounting for about 90% of cases. Circular RNA UBAP2 (circUBAP2) is involved in the progression of several types of cancers. However, the role of circUBAP2 in ESCC remains unclear. In the present study, circUBAP2 expression was found to be upregulated in ESCC tumour tissues. Knockdown of circUBAP2 through infection with lentiviral vector encoding shRNA targeting circUBAP2 (sh-circUBAP2) inhibited the proliferation, migration and invasion of ESCC cells. In addition, circUBAP2 significantly promoted the proliferation, migration and invasion of ESCC cells. In vivo xenograft assay demonstrated that circUBAP2 downregulation suppressed the tumour growth of ESCC. Further mechanism investigations proved that circUBAP2 exerted its role via sponging microRNA (miR)-422a, and miR-422a directly targeted Rab10 in ESCC cells. These findings suggested that circUBAP2 acted as oncogene through regulating the miR-422a/Rab10 axis in ESCC.

A novel lncRNA n384546 promotes thyroid papillary cancer progression and metastasis by acting as a competing endogenous RNA of miR-145-5p to regulate AKT3

Long noncoding RNAs (lncRNAs) are emerging as important regulators in the development of cancer cells. However, the role and mechanisms of most lncRNAs in papillary thyroid carcinoma (PTC) remain unknown. In this study, we investigated lncRNA expression profiles of PTC using RNA-seq in two groups of PTC tissues and adjacent normal tissues, and validated by real-time PCR analysis in another 53 pairs of tissues. We identified a novel lncRNA, n384546, which is highly expressed in PTC tissues and cell lines. n384546 expression was associated with clinicopathological features of PTC patients, such as tumor size, lymph node metastasis, and TNM stage. Functionally, knockdown of n384546 inhibited PTC cell proliferation, invasion, and migration both in vitro and in vivo. In addition, we identified miR-145-5p as a key miRNA target of n384546 using online bioinformatics tools. Anti-miR-145 could partially reverse the effects of n384546 knockdown. Furthermore, we found that n384546 could regulate the expression of AKT3 by sponging miR-145-5p, which was confirmed using an in vitro luciferase assay. In conclusion, we validated n384546 as a novel oncogenic lncRNA in PTC and determined that the n384546/miR-145-5p/AKT3 pathway contributes to PTC progression, which might be used as potential therapeutic targets for PTC patients.

Development of a preoperative prediction nomogram for lymph node metastasis in colorectal cancer based on a novel serum miRNA signature and CT scans

BACKGROUND

Preoperative prediction of lymph node (LN) status is of crucial importance for appropriate treatment planning in patients with colorectal cancer (CRC). In this study, we sought to develop and validate a non-invasive nomogram model to preoperatively predict LN metastasis in CRC.

METHODS

Development of the nomogram entailed three subsequent stages with specific patient sets. In the discovery set (n = 20), LN-status-related miRNAs were screened from high-throughput sequencing data of human CRC serum samples. In the training set (n = 218), a miRNA panel-clinicopathologic nomogram was developed by logistic regression analysis for preoperative prediction of LN metastasis. In the validation set (n = 198), we validated the above nomogram with respect to its discrimination, calibration and clinical application.

FINDINGS

Four differently expressed miRNAs (miR-122-5p, miR-146b-5p, miR-186-5p and miR-193a-5p) were identified in the serum samples from CRC patients with and without LN metastasis, which also had regulatory effects on CRC cell migration. The combined miRNA panel could provide higher LN prediction capability compared with computed tomography (CT) scans (P < .0001 in both the training and validation sets). Furthermore, a nomogram integrating the miRNA-based panel and CT-reported LN status was constructed in the training set, which performed well in both the training and validation sets (AUC: 0.913 and 0.883, respectively). Decision curve analysis demonstrated the clinical usefulness of the nomogram.

INTERPRETATION

Our nomogram is a reliable prediction model that can be conveniently and efficiently used to improve the accuracy of preoperative prediction of LN metastasis in patients with CRC.

Up-regulation of microRNA-19b is associated with metastasis and predicts poor prognosis in patients with colorectal cancer

Recent evidence has demonstrated that microRNA-19b (miR-19b) is elevated and functions as a prognosis predictor in hepatocellular carcinoma and melanoma. However, its expression and clinical significance in colorectal cancer (CRC) remain unclear. The study aimed to identify the correlation between miR-19b expression and the clinicopathological features and prognosis of patients with CRC. In this study, we found that the levels of miR-19b were significantly up-regulated in CRC tissues and cell lines compared with matched adjacent non-cancerous tissues and human colon mucosal epithelial cell lines, and its expression was also increased in patients with lymph node metastasis compared with those patients with no lymph node metastasis. Meanwhile, the patients with distal metastasis have a higher miR-19b expression than those patients with no distal metastasis. The high expression of miR-19b in patients with CRC was associated with lymph node metastasis and distant metastasis. miR-19b expression was an independent prognostic indicator for overall survival of CRC patients. Moreover, patients with a high miR-19b expression have shorter overall survival times than those patients with a low miR-19b expression. In addition, an in vitro functional assay showed that miR-19b knockdown restrained the migration and invasion of HCT116 and SW480 cells. In summary, the study provides the first convincing statistical and experimental evidence that the up-regulation of miR-19b is associated with metastasis and predicts unfavorable prognosis in patients with CRC, suggesting that miR-19b may serve as a novel and promising prognostic biomarker in CRC.

The Long Noncoding RNA D63785 Regulates Chemotherapy Sensitivity in Human Gastric Cancer by Targeting miR-422a

Gastric cancer is one of the most prevalent tumor types in the world. Chemotherapy is the most common choice for cancer treatment. However, chemotherapy resistance and adverse side effects limit its clinical applications. Aberrant expression of long noncoding RNAs (lncRNAs) has been found in various stages of gastric cancer development and progression. In this study, we identified that an oncogenic lncRNA, long intergenic non-protein-coding RNA D63785 (lncR-D63785), is highly expressed in gastric cancer tissues and cells. Silencing of lncR-D63785 inhibited cell proliferation, cell migration and invasion in gastric cancer cell lines and reduced tumor volume and size in mice. We found that the expression of lncR-D63785 was inversely correlated with microRNA 422a (miR-422a) expression, which was involved in the downregulation of expression of myocyte enhancer factor-2D (MEF2D) and drug sensitivity. Knockdown of lncR-D63785 increased the expression of miR-422a and the sensitivity of gastric cancer cells to apoptosis induced by the anticancer drug doxorubicin (DOX). This indicates that lncR-D63785 acts as a competitive endogenous RNA (ceRNA) of miR-422a and promotes chemoresistance by blocking miR-422-dependent suppression of MEF2D. Together, our results suggest that the therapeutic suppression of lncR-D63785 alone or in combination with chemotherapeutic agents may be a promising strategy for treating gastric cancer.

MiR-422a regulates cellular metabolism and malignancy by targeting pyruvate dehydrogenase kinase 2 in gastric cancer

Increasing evidence indicates that dysregulation of microRNAs (miRNAs) plays a crucial role in human malignancies. Here, we showed that microRNA-422a (miR-422a) expression was dramatically downregulated in gastric cancer (GC) samples and cell lines compared with normal controls, and that its expression level was inversely related to tumor size and depth of infiltration. Functional studies revealed that the overexpression of miR-422a in GC tumor cells suppressed cell proliferation and migration, and drove a metabolic shift from aerobic glycolysis to oxidative phosphorylation. Mechanistic analysis suggested that miR-422a repressed pyruvate dehydrogenase kinase 2 (PDK2) to restore activity of the pyruvate dehydrogenase (PDH), the gatekeeping enzyme that catalyzes the decarboxylation of pyruvate to produce acetyl-CoA. Importantly, we further demonstrated that the mir-422a–PDK2 axis also influenced another metabolic pathway, de novo lipogenesis in cancer cells, and that it subsequently affected reactive oxygen species (ROS) and RB phosphorylation levels, ultimately resulting in cell cycle arrest in G1 phase. Our findings show that the miR-422a–PDK2 axis is an important mediator in metabolic reprogramming and a promising therapeutic target for antitumor treatment.

Prognostic value of microRNAs in colorectal cancer: a meta-analysis

Background

Numerous studies have shown that miRNA levels are closely related to the survival time of patients with colon, rectal, or colorectal cancer (CRC). However, the outcomes of different investigations have been inconsistent. Accordingly, a meta-analysis was conducted to study associations among the three types of cancers.

Materials and methods

Studies published in English that estimated the expression levels of miRNAs with survival curves in CRC were identified until May 20, 2017 by online searches in PubMed, Embase, Web of Science, and the Cochrane Library by two independent authors. Pooled HRs with 95% CIs were used to estimate the correlation between miRNA expression and overall survival.

Results

A total of 63 relevant articles regarding 13 different miRNAs, with 10,254 patients were ultimately included. CRC patients with high expression of blood miR141 (HR 2.52, 95% CI 1.68-3.77), tissue miR21 (HR 1.31, 95% CI 1.12-1.53), miR181a (HR 1.52, 95% CI 1.26-1.83), or miR224 (HR 2.12, 95% CI 1.04-4.34), or low expression of tissue miR126 (HR 1.55, 95% CI 1.24-1.93) had significantly poor overall survival (P<0.05).

Conclusion

In general, blood miR141 and tissue miR21, miR181a, miR224, and miR126 had significant prognostic value. Among these, blood miR141 and tissue miR224 were strong biomarkers of prognosis for CRC.

miR-422a inhibits osteosarcoma proliferation by targeting BCL2L2 and KRAS

Osteosarcoma is the most common primary malignant bone tumor in children and adolescents. However, the underlying mechanism of osteosarcoma carcinogenesis and progression remains unknown. In the present study, we evaluated the expression profile of miRNAs in osteosarcoma tissues and the adjacent normal tissues. We found that the expression of miR-422a was down-regulated in osteosarcoma tissues and cell lines. In addition, we observed significantly elevated levels of repressive H3K9me3 and H3K27me3 and decreased active H3K4me3 on the promote region of miR-422a in osteosarcoma cells and clinical samples. Furthermore, up-regulation of miR-422a exhibited both in vitro and in vivo anti-tumor effects by inhibiting osteosarcoma cell growth and inducing apoptosis and cell cycle arrest. We also found that miR-422a targeted BCL2L2 and KRAS and negatively regulated their protein expression. Furthermore, restoration of miR-422a and knockdown of BCL2L2 and KRAS promoted apoptosis and induce cell cycle arrest in osteosarcoma cells. Taken together, the present study demonstrates that miR-422a may serve as a tumor suppressor in osteosarcoma via inhibiting BCL2L2 and KRAS translation both in vitro and in vivo. Therefore, miR-422a could be developed as a novel therapeutic target in osteosarcoma.

MiR-422a targets MAPKK6 and regulates cell growth and apoptosis in colorectal cancer cells

The important role of miR-422a in tumor has been reported in several studies. Recent research discovered that the expression of miR-422a was significantly decreased in colorectal cancer tissues, providing miR-422a as a tumor suppressor in CRC. However, the concrete mechanism of miR-422a regulating CRC cell is still unclear. In this study, we demonstrated that miR-422a could inhibit CRC cell growth and promote cell apoptosis via in vitro analyses. Moreover, computational methods were adopted to identify the targets of miR-422a. We found MAPKK6 was the direct target of miR-422a. Consequently, we further elucidated that miR-422a inhibited CRC cell growth and induced cell apoptosis by inhibiting p38/MAPK pathway. Besides that, we established the tumor xenograft model using nude mice and the inhibitory effects on tumor volumes and weights by miR-422a mimic transfection were also detected. Taken together, these findings demonstrated miR-422a exerted anti-cancer activities on CRC, which could be potentially used for CRC prognosis prediction and treatment.

Long intergenic non-protein coding RNA 00858 functions as a competing endogenous RNA for miR-422a to facilitate the cell growth in non-small cell lung cancer

The expression of long non-coding RNAs (lncRNAs) is dysregulated in non-small cell lung cancer (NSCLC). However, the functions and contributions of lncRNAs remain largely unknown. Here, we identified a critical role of long intergenic non-protein coding RNA 00858 (LINC00858) in NSCLC. Ectopic expression of LINC00858 in NSCLC cells promoted cell proliferation and induced cell migration and invasion. Moreover, LINC00858 functioned as a competitive endogenous RNA (ceRNA), effectively becoming sponge for miR-422a and thereby modulating the expression of kallikrein-related peptidase 4 (KLK4). In NSCLC patients, high expression of LINC00858 closely correlated with tumor progression. Thus, targeting the ceRNA network involving LINC00858 may be used as a treatment strategy against NSCLC.

miR-486-3p, miR-139-5p, and miR-21 as Biomarkers for the Detection of Oral Tongue Squamous Cell Carcinoma

Oral tongue squamous cell carcinoma (TSCC) is a complex disease with extensive genetic and epigenetic defects, including microRNA deregulation. The aims of the present study were to test the feasibility of performing the microRNA profiling analysis on archived TSCC specimens and to assess the potential diagnostic utility of the identified microRNA biomarkers for the detection of TSCC. TaqMan array-based microRNA profiling analysis was performed on 10 archived TSCC samples and their matching normal tissues. A panel of 12 differentially expressed microRNAs was identified. Eight of these differentially expressed microRNAs were validated in an independent sample set. A random forest (RF) classification model was built with miR-486-3p, miR-139-5p, and miR-21, and it was able to detect TSCC with a sensitivity of 100% and a specificity of 86.7% (overall error rate = 6.7%). As such, this study demonstrated the utility of the archived clinical specimens for microRNA biomarker discovery. The feasibility of using microRNA biomarkers (miR-486-3p, miR-139-5p, and miR-21) for the detection of TSCC was confirmed.

miR-422a inhibits cell proliferation in colorectal cancer by targeting AKT1 and MAPK1

BACKGROUND

miRNAs are regarded as molecular biomarkers and therapeutic targets for colorectal cancer (CRC), a series of miRNAs have been proven to involve into CRC carcinogenesis, invasion and metastasis. Aberrant miR-422a expression and its roles have been reported in some cancers. However, the function and underlying mechanism of miR-422a in the progression of CRC remain largely unknown.

METHODS

Real-time PCR were used to quantify miR-422a expression in CRC tissues. Both vivo and vitro functional assays showed miR-422a inhibits CRC cell proliferation. Target prediction program (miRBase) and luciferase reporter assays were conducted to confirm the target genes AKT1 and MAPK1 of miR-422a. Specimens from 50 patients with CRC were analyzed for the correlation between the expression of miR-422a and the expression of the target genes AKT1 and MAPK1 by real-time PCR.

RESULTS

MiR-422a was down‑regulated in CRC tissues and cell lines. Ectopic expression of miR-422a inhibited cell proliferation and tumor growth ability; inhibition of endogenous miR-422a, by contrast, promoted cell proliferation and tumor growth ability of CRC cells. MiR-422a directly targets 3'-UTR of the AKT1 and MAPK1, down-regulation of miR-422a led to the activation of Raf/MEK/ERK and PI3K/AKT signaling pathways to promote cell proliferation in CRC. In addition, miR-422a expression was negatively correlated with the expressions of AKT1 and MAPK1 in CRC tissues.

CONCLUSION

miR-422a inhibits cell proliferation in colorectal cancer by targeting AKT1 and MAPK1.

miR-486-3p, miR-139-5p, and miR-21 as Biomarkers for the Detection of Oral Tongue Squamous Cell Carcinoma

Oral tongue squamous cell carcinoma (TSCC) is a complex disease with extensive genetic and epigenetic defects, including microRNA deregulation. The aims of the present study were to test the feasibility of performing the microRNA profiling analysis on archived TSCC specimens and to assess the potential diagnostic utility of the identified microRNA biomarkers for the detection of TSCC. TaqMan array-based microRNA profiling analysis was performed on 10 archived TSCC samples and their matching normal tissues. A panel of 12 differentially expressed microRNAs was identified. Eight of these differentially expressed microRNAs were validated in an independent sample set. A random forest (RF) classification model was built with miR-486-3p, miR-139-5p, and miR-21, and it was able to detect TSCC with a sensitivity of 100% and a specificity of 86.7% (overall error rate = 6.7%). As such, this study demonstrated the utility of the archived clinical specimens for microRNA biomarker discovery. The feasibility of using microRNA biomarkers (miR-486-3p, miR-139-5p, and miR-21) for the detection of TSCC was confirmed.