miR-596 Modulates Melanoma Growth by Regulating Cell Survival and Death

Case report: Cytokine and miRNA profiling in multisystem inflammatory syndrome in children

Multisystem inflammatory syndrome in children (MIS-C) is an imperative pediatric inflammatory condition closely linked to COVID-19, which garners substantial attention since the onset of the pandemic. Like Kawasaki illness, this condition is characterized by an overactive immune response, leading to symptoms including pyrexia, cardiac and renal complications. To elucidate the pathogenesis of MIS-C and identify potential biomarkers, we conducted an extensive examination of specific cytokines (IL-6, IL-1β, IL-6R, IL-10, and TNF-α) and microRNA (miRNA) expression profiles at various intervals (ranging from 3 to 20 days) in the peripheral blood sample of a severely affected MIS-C patient. Our investigation revealed a gradual decline in circulating levels of IL-6, IL-1β, IL-10, and TNF-α following intravenous immune globulin (IVIG) therapy. Notably, IL-6 exhibited a significant reduction from 74.30 to 1.49 pg./mL, while IL-6R levels remained consistently stable throughout the disease course. Furthermore, we observed an inverse correlation between the expression of hsa-miR-596 and hsa-miR-224-5p and the aforementioned cytokines. Our findings underscore a robust association between blood cytokine and miRNA concentrations and the severity of MIS-C. These insights enhance our understanding of the genetic regulatory mechanisms implicated in MIS-C pathogenesis, offering potential avenues for early biomarker detection and therapy monitoring through miRNA analysis.

Epigenome-wide analysis of frailty: Results from two European twin cohorts

Epigenetics plays an important role in the aging process, but it is unclear whether epigenetic factors also influence frailty, an age-related state of physiological decline. In this study, we performed a meta-analysis of epigenome-wide association studies in four samples drawn from the Swedish Adoption/Twin Study of Aging (SATSA) and the Longitudinal Study of Aging Danish Twins (LSADT) to explore the association between DNA methylation and frailty. Frailty was defined using the frailty index (FI), and DNA methylation levels were measured in whole blood using Illumina's Infinium HumanMethylation450K and MethylationEPIC arrays. In the meta-analysis consisting of a total of 829 participants, we identified 589 CpG sites that were statistically significantly associated with either the continuous or categorical FI (false discovery rate <0.05). Many of these CpGs have previously been associated with age and age-related diseases. The identified sites were also largely directionally consistent in a longitudinal analysis using mixed-effects models in SATSA, where the participants were followed up to a maximum of 20 years. Moreover, we identified three differentially methylated regions within the MGRN1, MIR596, and TAPBP genes that have been linked to neuronal aging, tumor growth, and immune functions. Furthermore, our meta-analysis results replicated 34 of the 77 previously reported frailty-associated CpGs at p < 0.05. In conclusion, our findings demonstrate robust associations between frailty and DNA methylation levels in 589 novel CpGs, previously unidentified for frailty, and strengthen the role of neuronal/brain pathways in frailty.

GroEL of Porphyromonas gingivalis-induced microRNAs accelerate tumor neovascularization by downregulating thrombomodulin expression in endothelial progenitor cells

We found that GroEL in Porphyromonas gingivalis accelerated tumor growth and increased mortality in tumor-bearing mice; GroEL promoted proangiogenic function, which may be the reason for promoting tumor growth. To understand the regulatory mechanisms by which GroEL increases the proangiogenic function of endothelial progenitor cells (EPCs), we explored in this study. In EPCs, MTT assay, wound-healing assay, and tube formation assay were performed to analyze its activity. Western blot and immunoprecipitation were used to study the protein expression along with next-generation sequencing for miRNA expression. Finally, a murine tumorigenesis animal model was used to confirm the results of in vitro. The results indicated that thrombomodulin (TM) direct interacts with PI3 K/Akt to inhibit the activation of signaling pathways. When the expression of TM is decreased by GroEL stimulation, molecules in the PI3 K/Akt signaling axis are released and activated, resulting in increased migration and tube formation of EPCs. In addition, GroEL inhibits TM mRNA expression by activating miR-1248, miR-1291, and miR-5701. Losing the functions of miR-1248, miR-1291, and miR-5701 can effectively alleviate the GroEL-induced decrease in TM protein levels and inhibit the proangiogenic abilities of EPCs. These results were also confirmed in animal experiments. In conclusion, the intracellular domain of the TM of EPCs plays a negative regulatory role in the proangiogenic capabilities of EPCs, mainly through direct interaction between TM and PI3 K/Akt to inhibit the activation of signaling pathways. The effects of GroEL on tumor growth can be reduced by inhibiting the proangiogenic properties of EPCs through the inhibition of the expression of specific miRNAs.

Exosomal circPRRX1 functions as a ceRNA for miR-596 to promote the proliferation, migration, invasion, and reduce radiation sensitivity of gastric cancer cells via the upregulation of NF-κB activating protein

Exosomes, which are small extracellular vesicles, have been unveiled to carry circular RNAs (circRNAs). CircRNA paired-related homeobox 1 (circPRRX1) can be transferred by exosomes derived from gastric cancer cells. Here, we investigated the activity and mechanism of exosomal circPRRX1 in gastric tumorigenesis and radiation sensitivity. CircPRRX1, microRNA (miR)-596, and NF-κB activating protein (NKAP) were quantified by quantitative real-time PCR and immunoblotting. Cell proliferation, motility, and invasion were detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide and transwell assays, respectively. Cell colony formation and survival were assessed by colony formation assays. Dual-luciferase reporter assays were performed to verify the direct relationship between miR-596 and circPRRX1 or NKAP. In-vivo xenograft studies were used to evaluate the role of exosomal circPRRX1 in tumor growth. Our data showed that circPRRX1 expression was elevated in human gastric cancer, and circPRRX1 could be transferred by exosomes from gastric cancer cells. Exosomal circPRRX1 affected cell proliferation, motility, invasion, and radiation sensitivity in vitro and tumor growth in vivo. Mechanistically, circPRRX1 directly regulated miR-596 expression, and exosomal circPRRX1 affected cell biological functions at least in part through miR-596. NKAP was identified as a direct target and functionally downstream effector of miR-596. Exosomal circPRRX1 modulated NKAP expression by acting as a competing endogenous RNA (ceRNA) for miR-596. Our findings suggest a new mechanism, the exosomal circPRRX1/miR-596/NKAP ceRNA crosstalk, in regulating gastric tumorigenesis and radiation sensitivity.

Myeloid cell leukemia 1 (MCL-1): Structural characteristics and application in cancer therapy

Apoptosis, a major hallmark of cancer cells, regulates cellular fate and homeostasis. BCL-2 (B-cell CLL/Lymphoma 2) protein family is popularly known to mediate the intrinsic mode of apoptosis, of which MCL-1 is a crucial member. Myeloid cell leukemia 1 (MCL-1) is an anti-apoptotic oncoprotein and one of the most investigated members of the BCL-2 family. It is commonly known to be genetically altered, aberrantly overexpressed, and primarily associated with drug resistance in various human cancers. Recent advancements in the development of selective MCL-1 inhibitors and evaluating their effectiveness in cancer treatment establish its popularity as a molecular target. The overall aim is the selective induction of apoptosis in cancer cells by using a single or combination of BCL-2 family inhibitors. Delineating the precise molecular mechanisms associated with MCL-1-mediated cancer progression will certainly improve the efficacy of clinical interventions aimed at MCL-1 and hence patient survival. This review is structured to highlight the structural characteristics of MCL-1, its specific interactions with NOXA, MCL-1-regulatory microRNAs, and at the same time focus on the emerging therapeutic strategies targeting our protein of interest (MCL-1), alone or in combination with other treatments.

Identification of a methylomics-associated nomogram for predicting overall survival of stage I-II lung adenocarcinoma

The aim of this paper was to identify DNA methylation based biomarkers for predicting overall survival (OS) of stage I–II lung adenocarcinoma (LUAD) patients. Methylation profile data of patients with stage I–II LUAD from The Cancer Genome Atlas (TCGA) database was used to determine methylation sites-based hallmark for stage I–II LUAD patients’ OS. The patients were separated into training and validation datasets by using median risk score as cutoff. Univariate Cox, least absolute shrinkage and selection operator (LASSO) and multivariate Cox analyses were employed to develop a DNA methylation signature for OS of patients with stage I–II LUAD. As a result, an 11-DNA methylation signature was determined to be critically associated with the OS of patients with stage I–II LUAD. Analysis of receiver operating characteristics (ROC) suggested a high prognostic effectiveness of the 11-DNA methylation signature in patients with stage I–II LUAD (AUC at 1, 3, 5 years in training set were (0.849, 0.879, 0.831, respectively), validation set (0.742, 0.807, 0.904, respectively), entire TCGA dataset (0.747, 0.818, 0.870, respectively). Kaplan–Meier survival analyses exhibited that survival was significantly longer in the low-risk cohort compared to the high-risk cohort in the training dataset (P = 7e − 07), in the validation dataset (P = 1e − 08), and in the all-cohort dataset (P = 6e − 14). In addition, a nomogram was developed based on molecular factor (methylation risk score) as well as clinical factors (age and cancer status) (AUC at 1, 3, 5 years entire TCGA dataset were 0.770, 0.849, 0.979, respectively). The result verified that our methylomics-associated nomogram had a strong robustness for predicting stage I–II LUAD patients’ OS. Furthermore, the nomogram combined clinical and molecular factors to determine an individualized probability of recurrence for patients with stage I–II LUAD, which stood for a major advance in the field of personalized medicine for pulmonary oncology. Collectively, we successfully identified a DNA methylation biomarker and a DNA methylation-based nomogram to predict the OS of patients with stage I–II LUAD.

MicroRNA Signature in Melanoma: Biomarkers and Therapeutic Targets

Melanoma is the utmost fatal kind of skin neoplasms. Molecular changes occurring during the pathogenic processes of initiation and progression of melanoma are diverse and include activating mutations in BRAF and NRAS genes, hyper-activation of PI3K/AKT pathway, inactivation of p53 and alterations in CDK4/CDKN2A axis. Moreover, several miRNAs have been identified to be implicated in the biology of melanoma through modulation of expression of genes being involved in these pathways. In the current review, we provide a summary of the bulk of information about the role of miRNAs in the pathobiology of melanoma, their possible application as biomarkers and their emerging role as therapeutic targets for this kind of skin cancer.

Targeting MCL-1 in cancer: current status and perspectives

Myeloid leukemia 1 (MCL-1) is an antiapoptotic protein of the BCL-2 family that prevents apoptosis by binding to the pro-apoptotic BCL-2 proteins. Overexpression of MCL-1 is frequently observed in many tumor types and is closely associated with tumorigenesis, poor prognosis and drug resistance. The central role of MCL-1 in regulating the mitochondrial apoptotic pathway makes it an attractive target for cancer therapy. Significant progress has been made with regard to MCL-1 inhibitors, some of which have entered clinical trials. Here, we discuss the mechanism by which MCL-1 regulates cancer cell apoptosis and review the progress related to MCL-1 small molecule inhibitors and their role in cancer therapy.

Plasma exosomal miR-596: a novel biomarker predicts survival in patients with idiopathic pulmonary artery hypertension

Objective

To determine if plasma exosomal microRNAs (miRNAs) can predict survival in patients with idiopathic pulmonary arterial hypertension (IPAH).

Methods

The study enrolled patients with IPAH that underwent right heart catheterization. Plasma was collected and exosomal miRNAs were extracted. Exosomes were evaluated using transmission electron microscopy, Western blot analysis and particle size distribution analysis. MiRNAs were evaluated using a miRNA microarray and validated using real-time polymerase chain reaction.

Results

This study included 12 patients with IPAH in the study group and 48 patients with IPAH in the validation group. The mean ± SD follow-up duration was 60.3 ± 35.4 months in the overall cohort. The levels of miR-596 were higher in the nonsurvivors compared with the survivors. The levels of miR-596 significantly correlated with survival time, mean right atrial pressure, pulmonary vascular resistance (PVR) and cardiac index. High levels of miR-596 and PVR were significantly associated with poor overall survival. Multivariate analysis demonstrated that exosomal miR-596 (hazard ratio [HR] = 2.119; 95% confidence interval [CI] 1.402, 3.203) and PVR (HR = 1.146; 95% CI 1.010, 1.300) were independent predictors of survival.

Conclusions

High levels of plasma exosomal miR-596 were significantly associated with disease severity and poor prognosis of patients with IPAH.

MicroRNA-596 is epigenetically inactivated and suppresses prostatic cancer cell growth and migration via regulating Wnt/β-catenin signaling

OBJECTIVES

Although studies have reported that miR-596 extensively participates in multiple cancer progression, the biological mechanisms and effects of miR-596 in prostatic cancer remain unclear. The literature is aimed to reveal the function and possible molecular mechanisms of miR-596 in prostatic cancer carcinogenesis.

MATERIALS AND METHODS

qRT-PCR was applied to examine miR-596 expression in prostatic cancer cell lines and samples, also methylation-specific PCR was used to detect the methylation status of the promoter CpG islands in prostatic cancer samples. Meanwhile, the tumor-related effects of miR-596 were detected via cell viability, clone formation assay, migration assay, flow cytometric and AO/EB assay. qRT-PCR and Western blots were applied to investigate the function of miR-596 on malignant behavior in prostatic cancer cells.

RESULTS

We found that miR-596 mRNA was decreased in prostatic cancer samples and cell lines. miR-596 mRNA level was also correlated to cancer stage, Gleason scores, while miR-596 promoter methylation was related to cancer tumor stage, Gleason score and preoperative PSA levels. miR-596 inhibited the cell growth and activity by causing cell apoptosis, and also suppressed the migration of prostatic cancer cells by revealing the epithelial-mesenchymal transition process. In addition, Western blot indicates that miR-596 overexpression deregulated Wnt/β-catenin signaling, by restraining phosphorylation levels of β-catenin and expression levels of downstream targets.

CONCLUSIONS

In summary, this research indicates that miR-596 overexpression could be potentially useful in the cell growth and migration of prostatic cancer and serves as a potential molecular marker in prostatic cancer.

CircularRNA_0119872 regulates the microRNA-582-3p/E2F transcription factor 3 pathway to promote the progression of malignant melanoma

OBJECTIVES

Malignant melanoma (MM) is an invasive tumor that poses a threat to patient health. Circular RNAs (circRNAs) are important regulators of MM carcinogenesis. In this study, we investigated the expression characteristics and biological functions of, and mechanism underlying, circ_0119872 expression in MM.

METHODS

Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was employed to examine the circ_0119872, microRNA (miR)-582-3p, and E2F transcription factor 3 (E2F3) mRNA expression levels in MM tissues and cell lines. Western blotting was performed to quantify E2F3 protein expression. MM cells with circ_0119872 knockdown were established, and cell counting kit 8 (CCK-8) and transwell assays were utilized to examine the function of circ_0119872 and its effects on the malignant characteristics of MM cells. The MiRDB and TargetScan databases were used to predict the target genes of miR-582-3p. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was used to explore the biological functions of the target genes of miR-582-3p. Additionally, a dual-luciferase reporter gene experiment was performed to verify the targeting relationship between circ_0119872 and miR-582-3p as well as that between miR-582-3p and E2F3.

RESULTS

Circ_0119872 was remarkably upregulated in MM tissues and cell lines. Circ_0119872 knockdown suppressed the cell proliferation and metastasis In addition, miR-582-3p was identified as a downstream target of circ_0119872. The target genes of miR-193a-3p are involved in melanogenesis and cancer-related signaling pathways. Mechanistically, circ_0119872 facilitated MM progression by adsorbing miR-582-3p and upregulating E2F3 expression.

CONCLUSION

Circ_0119872 is an oncogenic circRNA that participates in the promotion of MM progression by regulating the miR-582-3p/E2F3 axis.

Silencing of lncRNA DLEU1 inhibits tumorigenesis of ovarian cancer via regulating miR-429/TFAP2A axis

Long non-coding RNAs (lncRNAs) are known as crucial regulators in the development of OC. In the current study, we aim to explore the function and molecular mechanism of lncRNA DLEU1 in OC. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to determine the expression of DLEU1, miR-429, and TFAP2A in OC cells and tissues. The relationship among DLEU1, miR-429, and TFAP2A was tested by dual-luciferase reporter (DLR) assay. Besides, the proliferative, migratory and invasive abilities of OC cells were analyzed by MTT, wound healing, and transwell assays, respectively. Western blot was performed to determine the protein expression of TFAP2A. The expression of lncRNA DLEU1 and TFAP2A were upregulated, and miR-429 was downregulated in OC tissues. Silencing of DLEU1 inhibited the proliferation, migration, and invasion of OC cells. Bioinformation and DLR assay showed that DLEU1 acted as the sponge for miR-429. Moreover, miR-429 could directly target TFAP2A and inhibit the proliferation, migration, and invasion of OC cells. Moreover, we observed a negative correlation between miR-429 and DLEU1, and between miR-429 and TFAP2A in OC tissues. The transfection of miR-429 inhibitor or pcDNA-TFAP2A reversed the inhibitory effects of si-DLEU1 on the proliferation, migration, and invasion of OC cells. Silencing of DLEU1 inhibited the proliferation, migration, and invasion of OC cells by regulating miR-429/TFAP2A axis, indicating a potential therapeutic target for OC.

miR-524-5p reduces the progression of the BRAF inhibitor-resistant melanoma

BRAF inhibitors were approved for the treatment of BRAF-mutant melanoma. However, most patients acquire the resistance to BRAF inhibitors after several months of treatment. miR-524-5p is considered as a tumor suppressor in many cancers, including melanoma. In this study, we investigated the biological functions of miR-524-5p in melanoma with acquired resistance to BRAF inhibitor and evaluated the endogenous miR-524-5p expression as a biomarker for melanoma. The results showed that the expression of miR-524-5p was 0.481-fold lower in melanoma tissues (n = 117) than in nevus tissues (n = 40). Overexpression of miR-524-5p significantly reduced proliferative, anchorage-independent growth, migratory and invasive abilities of BRAF inhibitor-resistant melanoma cells. Moreover, the introduction of miR-524-5p led to a reduced development of BRAF inhibitor-resistant melanoma in vivo. Remarkably, the MAPK/ERK signaling pathway was decreased after treatment with miR-524-5p. Furthermore, next-generation sequencing analysis implied that the complement system, leukocyte extravasation, liver X receptor/retinoid-X-receptor activation, and cAMP-mediated signaling may be related to miR-524-5p-induced pathways in the resistant cells. The miR-524-5p level was higher on average in complete response and long-term partial response patients than in progressive disease and short-term partial response patients treated with BRAF inhibitors. Our results proposed that miR-524-5p could be considered as a target for treatment BRAF inhibitor-resistant melanoma and a prognostic marker in the response of patients to BRAF inhibitors for melanoma.

MiR-596 activated by EP300 controls the tumorigenesis in epithelial ovarian cancer by declining BRD4 and KPNA4

Background

Epithelial ovarian cancer (EOC), a subclass of ovarian cancer (OC), is usually diagnosed at advanced stages due to the lack of effective screening means. Mounting reports have disclosed the vitally important roles of microRNAs (miRNAs) in carcinogenesis. Here, we aimed to find out possible miRNAs participating in EOC development.

Methods

qRT-PCR ad western blot respectively examined the mRNA and protein levels of studied genes. CCK-8, colony formation, flow cytometry, TUNEL and spheroid formation assays were appropriately employed for examining cell proliferation, cell cycle, apoptosis and stemness. The interaction between molecules was affirmed by luciferase reporter, RNA pull down and ChIP assays.

Results

In consistent with the observation of a past study, miR-596 expression was relatively low in EOC cells. Up-regulating miR-596 suppressed EOC cell proliferation and stemness. EP300 transcriptionally activated miR-596 to serve as a tumor-repressor in EOC. Then BRD4 and KPNA4, whose knockdown led to restraining effects on cell growth and stemness, were both revealed to be targeted by miR-596 in EOC. Lastly, rescue assays affirmed the tumor-restraining role of miR-596-BRD4/KPNA4 axis in EOC.

Conclusion

EP300-activated miR-596 hampered cell growth and stemness via targeting BRD4 and KPNA4 in EOC, proofing miR-596 as a promising therapeutic target in treating EOC patients.

RHPN1-AS1 Drives the Progression of Hepatocellular Carcinoma via Regulating miR-596/IGF2BP2 Axis

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most deadly cancer types worldwide, and its incidence is high in China. Multiple long non-coding RNAs (lncRNAs) have been recently identified as crucial oncogenic factors or tumor suppressors. In this study, we explored the effects of LncRNA RHPN1 antisense RNA 1 (RHPN1-AS1) on the progression of HCC.

METHODS

Expression levels of RHPN1-AS1 and miR-596 in HCC samples were measured by qRT-PCR. The association between pathological indexes and the expression level of RHPN1-AS1 was also analyzed. Human HCC cell lines Huh7 and SMMC-7721 were used as cell models. CCK-8 and colony formation assays were performed to assess the effect of RHPN1-AS1 on HCC cell line proliferation. The flow cytometer instrument was used to study the effect of RHPN1-AS1 on apoptosis of HCC cells. The transwell assay was conducted to detect the effect of RHPN1-AS1 on migration and invasion. Furthermore, luciferase reporter assay was used to confirm targeting of miR-596 by RHPN1-AS1. Additionally, the regulatory function of RHPN1-AS1 on insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) was detected by western blot.

RESULTS

The expression level of RHPN1-AS1 in HCC samples was observed to significantly increase compared with normal tissues and its high expression was correlated with unfavorable pathological indexes. Highly expressed RHPN1-AS1 was associated with shorter overall survival time. RHPN1-AS1 overexpression remarkably accelerated proliferation and metastasis of HCC cells, while reduced apoptosis. Accordingly, RHPN1-AS1 knockdown suppressed the malignant phenotypes of HCC cells. RHPN1-AS1 overexpression significantly reduced miR-596 expression by sponging it, but enhanced IGF2BP2 expression.

CONCLUSION

RHPN1-AS1 acts as a sponge of tumor suppressor miR-596 in HCC that can indirectly enhance the IGF2BP2 expression and function as an oncogenic lncRNA.

MiR-596 inhibits osteoblastic differentiation and cell proliferation by targeting Smad3 in steroid-induced osteonecrosis of femoral head

Background

It is reported that miR-596 has a potential diagnostic value for non-traumatic osteonecrosis of the femoral head (NOFH), but its underlying mechanisms in NOFH is unclear.

Methods

The expression of miR-596 and Smad3 was detected by western blot and quantitative real-time PCR. The relationship between the two molecules was explored using Dual-Luciferase Reporter Assay. Glucocorticoid (GC)—dexamethasone, was used to induce bone marrow mesenchymal stem cell (BMSC) osteogenic differentiation, and the effects of miR-596 on BMSC osteogenic differentiation and proliferation were determined.

Results

MiR-596 expression was upregulated, while Smad3 expression was inhibited in the bone marrow samples of patients with steroid-induced osteonecrosis of femoral head (SANFH). Overexpression of miR-596 inhibited the proliferation and osteogenic differentiation of BMSCs induced by GC. Meanwhile, the opposite results were observed in the miR-596 inhibitor group. In addition, Smad3 was a target gene of miR-596, and negatively regulated by miR-596. The promotion effect of the miR-596 inhibitor on BMSC proliferation and osteogenic differentiation was reversed by si-Smad3.

Conclusion

MiR-596 can suppress GC-BMSC osteoblastic differentiation and proliferation by regulating Smad3 expression.

Long non-coding RNA RHPN1-AS1 promotes tumorigenesis and metastasis of ovarian cancer by acting as a ceRNA against miR-596 and upregulating LETM1

Background: In recent decades, long non-coding RNAs (lncRNAs) have been reported as crucial functional regulators involved in ovarian cancer. In the present study, we explored how lncRNA RHPN1-AS1 influences the progression of epithelial ovarian cancer (EOC) through tumor cell-dependent mechanisms.

Results: The expression of RHPN1-AS1 in EOC tissues was higher than that in para-cancerous control tissues. High expression of RHPN1-AS1 was closely associated with poor prognosis in EOC patients. N6-methyladenosine (m6A) improved the stability of RHPN1-AS1 methylation transcript by reducing RNA degradation, which resulted in upregulation of RHPN1-AS1 in EOC. In vitro and in vivo functional experiments showed that RHPN1-AS1 promoted EOC cell proliferation and metastasis. RHPN1-AS1 acted as a ceRNA to sponge miR-596, consequently increasing LETM1 expression and activating the FAK/PI3K/Akt signaling pathway.

Conclusion: RHPN1-AS1-miR-596-LETM1 axis plays a crucial role in EOC progression. Our findings may provide promising drug targets for EOC treatment.

Methods: We determined the aberrantly expressed lncRNAs in EOC via microarray analysis and validated RHPN1-AS1 expression by qRT-PCR. The RHPN1-AS1-miR-596-LETM1 axis was examined by dual-luciferase reporter assay and RIP assay. The mechanism of RHPN1-AS1 was investigated through gain- and loss-of-function studies both in vivo and in vitro.

High-Resolution Bisulfite-Sequencing of Peripheral Blood DNA Methylation in Early-Onset and Familial Risk Breast Cancer Patients

PURPOSE

Understanding and explaining hereditary predisposition to cancer has focused on the genetic etiology of the disease. However, mutations in known genes associated with breast cancer, such as BRCA1 and BRCA2, account for less than 25% of familial cases of breast cancer. Recently, specific epigenetic modifications at BRCA1 have been shown to promote hereditary breast cancer, but the broader potential for epigenetic contribution to hereditary breast cancer is not yet well understood.

EXPERIMENTAL DESIGN

We examined DNA methylation through deep bisulfite sequencing of CpG islands and known promoter or regulatory regions in peripheral blood DNA from 99 patients with familial or early-onset breast or ovarian cancer, 6 unaffected BRCA mutation carriers, and 49 unaffected controls.

RESULTS

In 9% of patients, we observed altered methylation in the promoter regions of genes known to be involved in cancer, including hypermethylation at the tumor suppressor PTEN and hypomethylation at the proto-oncogene TEX14. These alterations occur in the form of allelic methylation that span up to hundreds of base pairs in length.

CONCLUSIONS

Our observations suggest a broader role for DNA methylation in early-onset, familial risk breast cancer. Further studies are warranted to clarify these mechanisms and the benefits of DNA methylation screening for early risk prediction of familial cancers.

CREPT promotes glioma cell proliferation and invasion by activating Wnt/β-catenin pathway and is a novel target of microRNA-596

Cell cycle-related and expression elevated protein in tumor (CREPT) is emerging as a novel cancer-related gene that is dysregulated in many kinds of malignancies. However, the expression and biological role of CREPT in glioma remains unclear. In the present study, we aimed to explore the potential function and regulation mechanism of CREPT in glioma. Results showed that CRETP expression was significantly upregulated in glioma cell lines. Depletion of CREPT by siRNA-mediated gene silencing markedly decreased the proliferative and invasive capabilities of glioma cells. Bioinformatics analysis predicted CREPT as a target gene of microRNA-596 (miR-596), which was further verified by real-time quantitative polymerase chain reaction and Western blot analysis. miR-596 was significantly decreased in glioma tissues and cell lines, and inversely correlated with CREPT expression in clinical specimens. Knockdown of CREPT or overexpression of miR-596 significantly restricted the activation of Wnt/β-catenin signaling in glioma cells. Moreover, overexpression of CREPT partially reversed the miR-596-mediated inhibitory effect on proliferation, invasion and Wnt/β-catenin signaling in glioma cells. Overall, these results demonstrate that CREPT exerts an oncogenic role in glioma and its expression is regulated by miR-596. Our study highlights the important role miR-596/CREPT/Wnt/β-catenin signaling axis may play in glioma.

MicroRNA-596 acts as a tumor suppressor in gastric cancer and is upregulated by promotor demethylation

BACKGROUND

In the present study, we investigated a suppressive role of microRNA-596 (miR-596) in gastric cancer (GC). Moreover, the downregulation of miR-596 in GC cell lines was associated with an increase of miR-596 promoter methylation. We also established that miR-596 controls the expression of peroxiredoxin 1 (PRDX1), which has never been reported before, suggesting that this interaction could play an important role in GC progression.

AIM

To study the potential role and possible regulatory mechanism of miR-596 in GC.

METHODS

The expression levels of miR-596 and PRDX1 in gastric cancer tissues and cell lines were detected by quantitative real-time PCR (qRT-PCR). Western blot and luciferase reporter assay were used to detect the effect of miR-596 on PRDX1 expression. Then, the proliferation, metastasis, and invasion of GC cell lines transfected with miR-596 mimics were analyzed, respectively, by Cell Counting Kit-8 proliferation assay, wound healing assay, and transwell invasion assay. Meanwhile, the methylation status of the promoter CpG islands of miR-596 in GC cell lines was detected by methylation-specific PCR (MSP).

RESULTS

Expression of miR-596 was decreased and PRDX1 was upregulated in GC tissues and cell lines. Overexpression of miR-596 decreased the expression of PRDX1 and luciferase reporter assays detected the direct binding of miR-596 to the 3'-untranslated region (UTR) of PRDX1 transcripts. Furthermore, we found that overexpression of miR-596 remarkably suppressed cell proliferation, migration, and invasion in GC cells. We further analyzed miR-596 promoter methylation by MSP and qRT-PCR, and found the downregulation of miR-596 was associated with promoter methylation status in GC cell lines. Moreover, DNA demethylation and reactivation of miR-596 after treatment with 5-Aza-2’-deoxycytidine inhibited the proliferative ability of GC cells.

CONCLUSION

MiR-596 has a tumor suppressive role in GC and is downregulated partly due to promoter hypermethylation. Furthermore, PRDX1 is one of the putative target genes of miR-596.