MiR-377 targets E2F3 and alters the NF-kB signaling pathway through MAP3K7 in malignant melanoma

Exosomes Derived from Hypertrophic Scar Fibroblasts Suppress Melanogenesis in Normal Human Epidermal Melanocytes

Post-burn hypertrophic scars often exhibit abnormal pigmentation. Exosomes play important roles in maintaining normal physiological homeostasis and in the pathological development of diseases. This study investigated the effects of the exosomes derived from hypertrophic scar fibroblasts (HTSFs) on melanocytes, which are pigment-producing cells. Normal fibroblasts (NFs) and HTSFs were isolated and cultured from normal skin and hypertrophic scar (HTS) tissue. Both the NF- and HTSF-exosomes were isolated from a cell culture medium and purified using a column-based technique. The normal human epidermal melanocytes were treated with both exosomes at a concentration of 100 μg/mL at different times. The cell proliferation, melanin content in the medium, apoptotic factors, transcription factors, melanin synthesis enzymes, signaling, signal transduction pathways, and activators of transcription factors (STAT) 1, 3, 5, and 6 were investigated. Compared with the Dulbecco's phosphate-buffered saline (DPBS)-treated controls and NF-exosomes, the HTSF-exosomes decreased the melanocyte proliferation and melanin secretion. The molecular patterns of apoptosis, proliferation, melanin synthesis, Smad and non-Smad signaling, and STATs were altered by the treatment with the HTSF-exosomes. No significant differences were observed between the DPBS-treated control and NF-exosome-treated cells. HTSF-derived exosomes may play a role in the pathological epidermal hypopigmentation observed in patients with HTS.

Inhibitory effect of miR-377 on the proliferative and invasive behaviors of prostate cancer cells through the modulation of MYC mRNA via its interaction with BCL-2/Bax, PTEN, and CDK4

The MYC gene is a regulatory and proto-oncogenic gene that is overexpressed in the majority of prostate cancers (PCa). Numerous studies have indicated that aberrant expression of microRNAs is involved in the initiation and progression of prostate cancer. In this investigation, we assessed the impact of miR-377 on MYC through luciferase assay. Real-time PCR was employed to determine whether miR-377 could reduce the levels of MYC mRNA in transfected PCa cell lines (PC-3 and DU145) and change in the mRNA levels of BCL-2/Bax, PTEN, and CDK4 as a consequence of MYC downregulation. Moreover, we analyzed the effects of miR-377 on apoptosis, proliferation, cell cycle, and wound healing. Our findings demonstrate that miR-377 effectively targets MYC mRNA, as confirmed by luciferase assay and Real-time PCR. We observed a significant reduction in BCL-2 and CDK4 expression, along with an increase in Bax and PTEN, in prostate cancer cell lines upon MYC suppression. Additionally, elevated levels of miR-377 in PCa cell lines induced apoptosis, inhibited proliferation and migration, and arrested the cell cycle. Taken together, these results unveil the inhibitory role of miR-377 in MYC function within PCa, thereby suggesting its potential as a therapeutic target for the treatment of this malignancy.

Inhibition of NF-κB signaling unveils novel strategies to overcome drug resistance in cancers

Drug resistance in cancer remains a major challenge in oncology, impeding the effectiveness of various treatment modalities. The nuclear factor-kappa B (NF-κB) signaling pathway has emerged as a critical player in the development of drug resistance in cancer cells. This comprehensive review explores the intricate relationship between NF-κB and drug resistance in cancer. We delve into the molecular mechanisms through which NF-κB activation contributes to resistance against chemotherapeutic agents, targeted therapies, and immunotherapies. Additionally, we discuss potential strategies to overcome this resistance by targeting NF-κB signaling, such as small molecule inhibitors and combination therapies. Understanding the multifaceted interactions between NF-κB and drug resistance is crucial for the development of more effective cancer treatment strategies. By dissecting the complex signaling network of NF-κB, we hope to shed light on novel therapeutic approaches that can enhance treatment outcomes, ultimately improving the prognosis for cancer patients. This review aims to provide a comprehensive overview of the current state of knowledge on NF-κB and its role in drug resistance, offering insights that may guide future research and therapeutic interventions in the fight against cancer.

MicroRNA-143 as a potential tumor suppressor in cancer: An insight into molecular targets and signaling pathways

MicroRNAs (MiRNAs), which are highly conserved and small noncoding RNAs, negatively regulate gene expression and influence signaling pathways involved in essential biological activities, including cell proliferation, differentiation, apoptosis, and cell invasion. MiRNAs have received much attention in the past decade due to their significant roles in cancer development. In particular, microRNA-143 (miR-143) is recognized as a tumor suppressor and is downregulated in most cancers. However, it seems that miR-143 is upregulated in rare cases, such as prostate cancer stem cells, and acts as an oncogene. The present review will outline the current studies illustrating the impact of miR-143 expression levels on cancer progression and discuss its target genes and their relevant signaling pathways to discover a potential therapeutic way for cancer.

The RNA interactome in the Hallmarks of Cancer

Ribonucleic acid (RNA) molecules are indispensable for cellular homeostasis in healthy and malignant cells. However, the functions of RNA extend well beyond that of a protein-coding template. Rather, both coding and non-coding RNA molecules function through critical interactions with a plethora of cellular molecules, including other RNAs, DNA, and proteins. Deconvoluting this RNA interactome, including the interacting partners, the nature of the interaction, and dynamic changes of these interactions in malignancies has yielded fundamental advances in knowledge and are emerging as a novel therapeutic strategy in cancer. Here, we present an RNA-centric review of recent advances in the field of RNA-RNA, RNA-protein, and RNA-DNA interactomic network analysis and their impact across the Hallmarks of Cancer. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes.

A preliminary study of calcium channel-associated mRNA and miRNA networks in post-traumatic epileptic rats

The calcium channels are the main pathogenesis and therapeutic target for post-traumatic epilepsy (PTE). However, differentially expressed miRNAs (DEMs) and mRNAs associated with calcium channels in PTE and their interactions are poorly understood. We produced a PTE model in rats and conducted RNA-seq in PTE rats. Gene annotation was used to verify differentially expressed mRNAs related to calcium channels. RNAhybrid, PITA, and Miranda prediction were used to build the miRNA-mRNA pairs. Furthermore, Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were used for the functional enrichment analysis of DEMs. The quantification changes of mRNA and miRNA were verified by RT-qPCR. There were 431 identified differentially expressed genes (DEGs) in PTE rats compared with the sham group, of which five mRNAs and 7 miRNAs were related to calcium channels. The miRNA-mRNA network suggested a negative correlation between 11 pairs of miRNA-mRNA involved in the p53 signaling pathway, HIF-1 signaling pathway. RT-qPCR verified three upregulated mRNAs in PTE rats, associated with 7 DEMs negatively related to them, respectively. This study has revealed the changes in miRNA-mRNA pairs associated with calcium channels in PTE, which might contribute to the further interpretation of potential underlying molecular mechanisms of PTE and the discovery of promising diagnostics.

MicroRNA-377: A therapeutic and diagnostic tumor marker

Cancer is considered as one of the main causes of human deaths globally. Despite the recent progresses in therapeutic modalities, there is still a high rate of mortality among cancer patients. Late diagnosis in advanced tumor stages is one of the main reasons for treatment failure in cancer patients. Therefore, it is required to suggest the novel strategies for the early tumor detection. MicroRNAs (miRNAs) have critical roles in neoplastic transformation by regulation of cell proliferation, migration, and apoptosis. They are always considered as non-invasive markers due to their high stability in body fluids. Since, all of the miRNAs have tissue-specific functions in different tumors as tumor suppressor or oncogene; it is required to investigate the molecular mechanisms of every miRNA in different tumors to introduce that as a suitable non-invasive diagnostic marker in cancer patients. For the first time in the present review, we discussed the role of miR-377 during tumor progression. It has been reported that miR-377 mainly functions as a tumor suppressor through the regulation of signaling pathways and transcription factors. This review is an important step toward introducing the miR-377 as a novel diagnostic marker as well as a therapeutic target in cancer patients.

Long non-coding RNAs involved in retinoblastoma

INTRODUCTION

Retinoblastoma (RB) is the most common childhood tumor that can occur in the retina and develop in a sporadic or heritable form. Although various traditional treatment options have been used for patients with RB, identifying novel strategies for childhood cancers is necessary.

MATERIAL AND METHODS

Recently, molecular-based targeted therapies have opened a greater therapeutic window for RB. Long non-coding RNAs (lncRNAs) presented a potential role as a biomarker for the detection of RB in various stages.

CONCLUSION

LncRNAs by targeting several miRNA/transcription factors play critical roles in the stimulation or suppression of RB. In this review, we summarized recent progress on the functions of tumor suppressors or oncogenes lncRNAs in RB.

Role of non-coding RNAs and exosomal non-coding RNAs in retinoblastoma progression

Retinoblastoma (RB) is a rare aggressive intraocular malignancy of childhood that has the potential to affect vision, and can even be fatal in some children. While the tumor can be controlled efficiently at early stages, metastatic tumors lead to high mortality. Non-coding RNAs (ncRNAs) are implicated in a number of physiological cellular process, including differentiation, proliferation, migration, and invasion, The deregulation of ncRNAs is correlated with several diseases, particularly cancer. ncRNAs are categorized into two main groups based on their length, i.e. short and long ncRNAs. Moreover, ncRNA deregulation has been demonstrated to play a role in the pathogenesis and development of RB. Several ncRNAs, such as miR-491-3p, miR-613,and SUSD2 have been found to act as tumor suppressor genes in RB, but other ncRNAs, such as circ-E2F3, NEAT1, and TUG1 act as tumor promoter genes. Understanding the regulatory mechanisms of ncRNAs can provide new opportunities for RB therapy. In the present review, we discuss the functional roles of the most important ncRNAs in RB, their interaction with the genes responsible for RB initiation and progression, and possible future clinical applications as diagnostic and prognostic tools or as therapeutic targets.

MiR-199a-3p Induces Mesenchymal to Epithelial Transition of Keratinocytes by Targeting RAP2B

Cutaneous squamous cell carcinoma (CSCC) is an epidermal skin cancer that evolves from normal epidermis along several pre-malignant stages. Previously we found specific miRNAs alterations in each step along these stages. miR-199a-3p expression decreases at the transition to later stages. A crucial step for epithelial carcinoma cells to acquire invasive capacity is the disruption of cell-cell contacts and the gain of mesenchymal motile phenotype, a process known as epithelial-to-mesenchymal transition (EMT). This study aims to study the role of decreased expression of miR-199a-3p in keratinocytes' EMT towards carcinogenesis. First, we measured miR-199a-3p in different stages of epidermal carcinogenesis. Then, we applied Photoactivatable Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation (PAR-CLIP) assay to search for possible biochemical targets of miR-199a-3p and verified that Ras-associated protein B2 (RAP2B) is a bona-fide target of miR-199a-3p. Next, we analyzed RAP2B expression, in CSCC biopsies. Last, we evaluated possible mechanisms leading to decreased miR-199a-3p expression. miR-199a-3p induces a mesenchymal to epithelial transition (MET) in CSSC cells. Many of the under-expressed genes in CSCC overexpressing miR-199a-3p, are possible targets of miR-199a-3p and play roles in EMT. RAP2B is a biochemical target of miR-199a-3p. Overexpression of miR-199a-3p in CSCC results in decreased phosphorylated focal adhesion kinase (FAK). In addition, inhibiting FAK phosphorylation inhibits EMT marker genes' expression. In addition, we proved that DNA methylation is part of the mechanism by which miR-199a-3p expression is inhibited. However, it is not by the methylation of miR-199a putative promoter. These findings suggest that miR-199a-3p inhibits the EMT process by targeting RAP2B. Inhibitors of RAP2B or FAK may be effective therapeutic agents for CSCC.

Non-coding RNAs in skin cancers:Biological roles and molecular mechanisms

Cutaneous malignancies, including basal cell carcinoma, cutaneous squamous cell carcinoma, and cutaneous melanoma, are common human tumors. The incidence of cutaneous malignancies is increasing worldwide, and the leading cause of death is malignant invasion and metastasis. The molecular biology of oncogenes has drawn researchers’ attention because of the potential for targeted therapies. Noncoding RNAs, including microRNAs, long noncoding RNAs, and circular RNAs, have been studied extensively in recent years. This review summarizes the aspects of noncoding RNAs related to the metastasis mechanism of skin malignancies. Continuous research may facilitate the identification of new therapeutic targets and help elucidate the mechanism of tumor metastasis, thus providing new opportunities to improve the survival rate of patients with skin malignancies.

Transcription factor YY1 contributes to human melanoma cell growth through modulating the p53 signaling pathway

BACKGROUND

Melanoma has a higher mortality rate than any other skin cancer, and its cases are increasing. The transcription factor YY1 has been proven to be involved in tumor progression; however, the role of YY1 in melanoma is not well understood.

METHODS

This study investigates how YY1 functions in melanoma progression, and it also elucidates the underlying mechanisms involved.

RESULTS

We have found that in clinical human melanoma tissues, YY1 is overexpressed compared to YY1 expression in normal melanocytes and skin tissues. Cellular immunofluorescence shows that YY1 is mainly located in the nucleus. YY1 knockdown reduces proliferation, migration, and invasion of melanoma cell lines. Moreover, the apoptosis rate of cells is significantly increased in low-YY1 environments. The overexpression of YY1 resulted in decreased apoptotic rates in melanoma cells. YY1 also affects the expression of EMT-related proteins. Additional experiments reveal that YY1 knockdown disrupts the interaction of MDM2-p53, and that it both stabilizes and increases p53 activity. The upregulation of p53 expression in turn stimulates p21 expression just as it suppresses CDK4 expression, which then induces cells that were arrested in the G1 phase. The effect then is to constrain cell proliferation in melanoma cells. Upon activation of the p53 pathway, Bax, a pro-apoptotic protein, is upregulated, and Bcl-2, an anti-apoptotic protein, was downregulated in A375 cells.

CONCLUSIONS

The findings of this study provide novel insights into the pathology of melanoma as well as the role that YY1 plays in tumor progression. The findings also suggest that targeting YY1 has the potential to improve the diagnosis and treatment of melanoma.

Overexpression of lncRNA HULC Attenuates Myocardial Ischemia/reperfusion Injury in Rat Models and Apoptosis of Hypoxia/reoxygenation Cardiomyocytes via Targeting miR-377-5p through NLRP3/Caspase‑1/IL‑1β Signaling Pathway Inhibition

OBJECTIVE

Acute myocardial infarction (AMI) is characterized by myocardial tissue necrosis and activation of inflammatory response. This study aims to elucidate the potential mechanism underlying the protective effects of long non-coding RNA (lncRNA) highly up-regulated in liver cancer (HULC) against myocardial ischemia/reperfusion (I/R) injury in rat models and apoptosis of cardiomyocytes.

METHODS

We firstly established rat models of myocardial I/R injury and rat cardiomyocyte (H9c2 cells) models of hypoxia/reoxygenation (H/R) injury. Sprague-Dawley (SD) neonatal rats were randomized into four groups: sham, I/R, I/R+ microRNA (miR) -377-5p mimic, and I/R+ miR-377-5p antagomir, respectively. Then, histopathological examination was applied. Apoptosis was evaluated by transferase-mediated dUTP nick end labeling (TUNEL) staining. Cell vitality was measured using MTT assay. The concentrations of creatine kinase MB (CK-MB), cardiac troponin I (cTnI), interleukin (IL) -6 (IL-6), and tumor necrosis factor-α (TNF-α) were detected by enzyme-linked immunosorbent assay (ELISA). The expression of Cleaved-Caspase-3, Caspase-3, NOD-like receptor P3 (NLRP3), Caspase-1, and IL-1β was analyzed by immunohistochemical (IHC) or Western blot analysis.

RESULTS

We found that HULC was downregulated and miR-377-5p was upregulated in IR-injured myocardial tissue and the H/R-induced H9c2 cell. Overexpression of miR-377-5p increased myocardial dysfunction and apoptosis and activated formation and secretion of IL-6 and TNF-α. The preprocessing of miR-377-5p silencing emerged opposite results. Strikingly, dual luciferase reporter assay showed that HULC was a sponge of miR-377-5p. Subsequently, mechanism experiments revealed that NLRP3/Caspase‑1/IL‑1β was a target axis of miR-377-5p. In vitro, the protective effect of HULC overexpression on H9c2 cell viability and inflammation was offset by miR-377-5p silencing. Finally, rescue assay suggested that HULC-miR-377-5p -NLRP3/Caspase‑1/IL‑1β axis regulated the apoptosis and inflammation of H/R-induced H9c2 cells.

CONCLUSIONS

Overall, these results indicate that the protective effect of HULC against myocardial I/R injury and H/R cardiomyocyte apoptosis partially relies on the inhibition of NLRP3/Caspase‑1/IL‑1β signaling pathway.

The role of miRNA-377 as a tumor suppressor in lung cancer by negative regulation of genes belonging to ErbB signaling pathway

BACKGROUND

The ErbB signaling pathway plays important role in the pathogenesis of lung cancer. We explored the role of miRNA-377 as a tumor suppressor in NSCLC through silencing of some genes in the ErbB pathway.

METHODS AND RESULTS

The targeting effect of miRNA-377 on EGFR, MAPK1, ABL2, and PAK2 was evaluated. The expression levels of these genes and miRNA-377 were surveyed in NSCLC and normal human tissues, Calu-6, and A549 cells. Real-time PCR was used to figure out whether miRNA-377 could decrease the target genes mRNAs in transfected lung cancer cell lines. The effects of miRNA-377 on apoptosis cell and proliferation were analyzed. We showed that miRNA-377 targets EGFR, MAPK1, and PAK2 mRNAs in in-silico and luciferase reporter assay. The expression of miRNA-377 was significantly downregulated in human NSCLC tissues, Calu-6 and A549 cells compared to their controls. We observed a negative correlation between EGFR, MAPK1, PAK2, and miRNA-377 expression in human NSCLC tissues. A significant reduction in EGFR, MAPK1, and PAK2 mRNA levels was detected, following miRNA-377 transfection in Calu-6 and A549 cells. The higher levels of miRNA-377 in Calu-6, and A549 cells induced apoptosis and reduced proliferation, significantly.

CONCLUSIONS

All these data reveal that miRNA-377 functions as a tumor suppressor in NSCLC and may serve as a potential therapeutic target for the treatment of NSCLC.

Overexpressed miR-375-Loaded Restrains Development of Cervical Cancer Through Down-Regulation of Frizzled Class Receptor 4 (FZD4) with Liposome Nanoparticle as a Carrier

Dysregulation expression of miR-375 is noted to correlate with progression of cervical cancer. This study attempted to investigate the impact of overexpressed miR-375-loaded liposome nanoparticles on proliferation of cervical cancer (CC), to provide an insight on pathogenesis of CC disorder. CC cells were co-cultured with pure liposome nanoparticles (empty vector group), miR-375 agonist-loaded liposome nanoparticles, or transfected with miR-375 antagonist. Besides, some cells were exposed to TGF-β/Smads signaling pathway inhibitor or activator whilst cell proliferation was assessed by MTT assay, and expressions of FZD4 and miR-375 were determined. Western blot analysis was carried out to detect the expression of TGF-β pathway factors (TGF-β, Smad2, Smad7, p-Smad2) and its downstream Smads pathway. The interaction between miR-375 and FZD4 was evaluated by dual-luciferase reporter gene assay. Overexpression of miR-375 induced arrest at the G0/G1 phase of cell cycle and elevation of Smad2 protein expression (P <0.05), with lower expressions of TGF-β, Smad7, p-Smad2, and FZD4, while transfection with miR-375 inhibitor exhibited opposite activity. Presence of miR-375 agonist-loaded liposome nanoparticles induced decreased cell proliferation. There was a targeting relationship between miR-375 and FZD4, and administration with TGF-β/Smads agonist resulted in increased miR-375 and Smad2 expressions, as well as decreased TGF-β, Smad7, p-Smad2, FZD4 protein expression, and the number of S phase and G2/M phase cells (P < 0.05). The signaling inhibitor oppositely suppressed cell proliferation decreasing miR-375 expression. miR-375-loaded liposome nanoparticles activated TGF-β/Smads signaling pathway to restrain cell cycle and suppress cell division, and proliferation through targeting FZD4 in CC. Its molecular mechanism is related to activation of TGF-β/Smads signaling pathway.

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.

Cisplatin inhibits the proliferation of Saos-2 osteosarcoma cells via the miR-376c/TGFA pathway

The transforming growth factor alpha (TGFA) gene is involved in the proliferation and metastasis of various tumors, but its role in cell sensitivity to cisplatin chemotherapy is unclear. In this study, we investigated the mechanism underlying inhibitory effects of cisplatin on growth and proliferation of osteosarcoma cells. Osteosarcoma and normal skeletal muscle tissues were collected from 26 patients by biopsy. TGFA was silenced or overexpressed in Saos-2 osteosarcoma cells by transfection with TGFA-shRNA or TGFA ORF clone, respectively. MiR-376c was inhibited or overexpressed by transfection of Saos-2 cells with miR-376c sponge or miR-376c mimics, respectively. Cell growth was analyzed by MTT assay and cell proliferation by BrdU assay. MiR-376c and TGFA mRNA expression was detected by quantitative reverse transcription PCR and TGFA protein expression by Western blot. The target relationship between miR-376c and TGFA was assessed by luciferase reporter assay. Both in osteosarcoma tissues and Saos-2 cells, miR-376c expression was significantly decreased and TGFA mRNA expression was significantly increased compared with control. Transfection of Saos-2 cells with TGFA-shRNA silenced TGFA expression and significantly inhibited cell growth and proliferation. TGFA mRNA and protein expression in Saos-2 cells significantly decreased with increasing cisplatin concentrations (2.5–10 mg/L). Transfection with TGFA ORF clone reversed the inhibitory effects of cisplatin on Saos-2 cell proliferation. Compared with cisplatin (10 mg/L) treatment alone, the combined treatment with cisplatin and miR-376c mimics inhibited the proliferation of Saos-2 cells more significantly. MiR-376c suppressed TGFA expression by directly interacting with its 3’ UTR region. Overall, cisplatin inhibited the proliferation of Saos-2 cells by upregulating miR-376c and downregulating TGFA expression.

Circ_0072088 Promotes Proliferation, Migration, and Invasion of Esophageal Squamous Cell Cancer by Absorbing miR-377

Circular RNA (circRNA) is an endogenous noncoding RNA. Accumulative investigations have confirmed that circRNAs play a vital role in carcinogenesis and tumor progression. Herein, we examined the expression and mechanism of circ_0072088 in esophageal squamous cell carcinoma (ESCC). As a result, circ_0072088 was significantly overexpressed in ESCC tissues and cells, which was closely associated with tumor size, invasion depth, clinical stage, and lymph node metastasis of esophageal cancer. Nuclear and cytoplasmic separation as well as FISH assays showed that circ_0072088 was mainly localized in the cytoplasm of ESCC cells. RNase R treatment assay revealed that circ_0072088 was steadier than linear ZFR mRNA. circ_0072088 promoted ESCC cell proliferation, migration and invasion in vitro, and cell proliferation in vivo. Mechanistically, circ_0072088 upregulated VEGF gene expression by acting as the sponge of miRNA-377. In conclusion, circ_0072088 might be used as a diagnostic biomarker and therapeutic target for ESCC.

IL6R is a target of miR-197 in human keratinocytes

Psoriasis is a chronic inflammatory disorder with cutaneous and systemic manifestations and substantial negative effects on patients' quality of life. MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression that play a role in the pathogenesis of psoriasis. Previously studies, from others and by us, highlighted specific miRNAs that are dysregulated in psoriatic lesions. MicroRNA-197-3p (miR-197) expression is downregulated in psoriatic lesions compared to normal or uninvolved skin in patients with psoriasis. We have previously reported that miR-197 could modulate IL-22 and IL-17 signalling in psoriasis. Herein, we identify additional biochemical targets of miR-197 in psoriasis. We applied a transcriptome-wide biochemical approach, Protein argonaute-2 photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation (Ago2 PAR-CLIP), to search for new targets of miR-197 in live keratinocytes, and validated its results using reporter assay and analysing by Western blot protein levels in cells overexpressing miR-197. Ago2 PAR-CLIP identified biochemical targets of miR-197, including the alpha subunit of the IL-6 receptor (IL6R). This work provides evidence that IL6R in bona-fide biochemical target of miR-197. IL6R is known to be up-regulated in psoriasis and even was considered as a possible therapeutic target. From the present data and our previous studies, it appears that miR-197 is a major regulator of the interaction between immune system cells and keratinocytes.

Downregulation of miR‑181b inhibits human colon cancer cell proliferation by targeting CYLD and inhibiting the NF‑κB signaling pathway

It has been reported that microRNA (miRNA/miR)-181b plays an important role in regulating cellular proliferation, invasion and apoptosis in various tumors. However, the role of miR-181b and its molecular mechanisms in colon cancer cells have not yet been elucidated. The present study thus aimed to investigate the mechanisms of miR-181b targeting cylindromatosis (CYLD) to regulate the nuclear factor-κB (NF-κB) signaling pathway, and to determine its role in colon cancer cell proliferation and apoptosis. For this purpose, miR-181b was overexpressed and silenced in the SW480 cell line. The cell proliferation and apoptotic rates were determined using a Cell Counting kit and colony formation assays, and Annexin V-FITC staining, respectively. The expression levels of proteins associated with the NF-κB signaling pathway and apoptosis were detected by western blot analysis. Furthermore, a dual luciferase assay was applied to confirm the interaction between miR-181b and CYLD. CYLD was also overexpressed and silenced in the SW480 cell line using a CYLD overexpression plasmid and siRNA technology, respectively. Transfected cells were used for subsequent experiments. In addition, a nude mouse model was established to measure tumor volume and weight. Immunohistochemistry and a TUNEL assay were performed to detect the Ki67 levels and the cell apoptotic rate, respectively. Compared with the control group, miR-181 silencing or CYLD overexpression significantly attenuated cell proliferation, invasion and migration, and notably increased the proportion of apoptotic cells. Furthermore, the expression levels of Bax and cleaved caspase-3 were markedly increased, whereas those of Bcl-2 were significantly decresaed (P<0.05). In addition, the protein expression levels of p-p65/p65 and p-IκBα/IκBα were significantly down-regulated and upregulated, respectively (P<0.05). Consistent with the results obtained in vitro, in vivo experiments using a nude mouse model yielded similar findings. The aforementioned results indicated that miR-181b down-regulation inhibited human colon cancer cell proliferation by targeting CYLD to attenuate the activity of the NF-κB signaling pathway.

The lncRNA XIST promotes proliferation, migration and invasion of gastric cancer cells by targeting miR-337

BACKGROUND AND STUDY AIMS

Gastric cancer (GC) is one of the most common malignant tumours worldwide. Long non-coding RNAs (lncRNAs) and microRNAs regulate the occurrence and development of various cancers and play an important role in GC progression. X-inactive specific transcript (XIST), a carcinogenic lncRNA, is involved in human tumourigenesis and is altered in GC. Janus kinase 2 (JAK2), a transcription factor, is involved in cancer cell metastasis and differentiation. However, the exact mechanism underlying the biological roles of XIST and JAK2 in cancer cells remains unclear.

MATERIAL AND METHODS

This study was conducted using GES-1, HGC-27, AGS and HEK-293 T cells. Quantitative polymerase chain reaction and western blotting were performed to detect XIST, microRNA-337 (miR-337) and JAK2 expressions. GC cell invasion was investigated by using the Transwell assay. Fluorescein reporter gene detection was used to determine the relationship between JAK2 and XIST.

RESULTS

Compared with that in GES-1 cells, XIST expression was significantly up-regulated in AGS and HGC-27 cells. miR-337 expression in GC cell lines was decreased. The proliferation, invasion and migration of GC cells were simultaneously inhibited by XIST knockdown, and the relationship between XIST and miR-337 was confirmed by bioinformatics analysis. JAK2 is expected to be the target gene of miR-337. MiR-337 can negatively regulate JAK2 expression in vitro. In addition, si-XIST decreased JAK2 expression by up-regulating miR-337 in vitro, thereby inhibiting GC cell proliferation and migration. Therefore, we speculated that XIST regulates JAK2 by competing with miR-337 as a competitive endogenous lncRNA in GC.

CONCLUSION

We elucidated the effects of migration and invasion after XIST inhibition, at least in part, by inhibiting miR-337 expression in GC cells to regulate JAK2. These data indicate that a positive feedback loop exists between XIST and JAK2 and suggest that JAK2 and XIST play a vital role in cancer cell migration and invasion.

microRNA-377 acts as a suppressor in esophageal squamous cell carcinoma through CBX3-dependent P53/P21 pathway

Stem cells play pivotal roles in esophageal squamous cell carcinoma (ESCC) recurrence and metastasis. The self-renewal ability of stem cells was associated with specific microRNAs (miRs). Herein, we identified the effects of miR-377 on ESCC stem cell activities. First, the expression of miR-377 in ESCC and adjacent normal tissues was determined. The relationship between miR-377 and chromobox protein homolog 3 (CBX3) was assessed by a dual-luciferase reporter gene assay. miR-377 was overexpressed or inhibited in ESCC stem cells to explore its role in ESCC. To further investigate the mechanism of miR-377 in ESCC, cells were introduced with short hairpin RNA against CBX3 or pifithrin-α (inhibitor of P53 pathway). Besides, the expression of P21, P53, CD133, CD13, Nanog, sex determining region Y-Box 2 (Sox2), and octamer-binding transcription factor 4 (Oct4), cell sphere formation, colony formation, and proliferation were evaluated respectively. Finally, limiting dilution assay in vivo and tumor xenograft in nude mice were conducted to confirm the roles of miR-377 in vivo. miR-377 was poorly expressed in ESCC. Overexpression of miR-377 could suppress the stem-like trait of ESCC as well as the tumor growth in vivo. miR-377 targeted CBX3 to activate the P53/P21 pathway. Besides, the expression of stem-like markers including CD133, CD13, Oct4, Sox2, and Nanog was decreased, and the abilities of cell sphere formation, colony formation, proliferation, and tumorigenicity were significantly reduced by overexpressing miR-377 or silencing CBX3. The results were reversed after inactivating the P53/P21 pathway. In summary, upregulation of miR-377 inhibits the self-renewal of ESCC stem cells by inhibiting CBX3 expression and promoting activation of the P53/P21 pathway.

Long non-coding RNA CASC9 promotes the progression of retinoblastoma via interacting with miR-145-5p

Abnormal expression of long non-coding RNA cancer susceptibility candidate 9 (CASC9) has been found to play vital roles in many human tumors. However, the role and the regulatory mechanism of CASC9 have not yet been demonstrated in retinoblastoma (RB). Hence, we performed this study to explore the function and mechanism of CASC9 in RB. CASC9 expression was firstly detected in human RB tissues and cells. The influence of CASC9 on the malignant phenotypes of RB cells, including cell proliferation, invasion, epithelial-mesenchymal transition (EMT) and apoptosis, was analyzed by overexpressing or silencing CASC9. The association between CASC9, miR-145-5p and E2F transcription factor 3 (E2F3) was determined by dual-luciferase reporter assay and RNA immunoprecipitation. We found that CASC9 expression was elevated in RB tissues and cells. Overexpression of CASC9 significantly facilitated the proliferation, invasion and EMT of RB cells. On the contrary, knockdown of CASC9 inhibited the proliferation, invasion and EMT, while enhanced the apoptosis of RB cells. CASC9 acted as a competing endogenous RNA (ceRNA) for miR-145-5p to regulate E2F3. Additionally, miR-145-5p inhibitor and E2F3 overexpression both partly reversed the malignant phenotypes of RB cells affected by CASC9 knockdown. However, miR-145-5p overexpression further strengthened these features induced by CASC9 downregulation. These findings suggested that CASC9 contributed to RB development by regulating E2F3 via sponging miR-145-5p. CASC9 might be a possible therapeutic target for RB.

A novel LncRNA transcript, RBAT1, accelerates tumorigenesis through interacting with HNRNPL and cis-activating E2F3

BACKGROUND

Long non-coding RNAs (lncRNAs) have been identified as important epigenetic regulators that play critical roles in human cancers. However, the regulatory functions of lncRNAs in tumorigenesis remains to be elucidated. Here, we aimed to investigate the molecular mechanisms and potential clinical application of a novel lncRNA, retinoblastoma associated transcript-1 (RBAT1), in tumorigenesis.

METHODS

RBAT1 expression was determined by real-time PCR in both retinoblastoma (Rb) and bladder cancer (BCa) cell lines and clinical tissues. Chromatin isolation using RNA purification (ChIRP) assays were performed to identify RBAT1-interacting proteins. Patient-derived xenograft (PDX) retinoblastoma models were established to test the therapeutic potential of RBAT1-targeting GapmeRs.

RESULTS

Here, we found that RBAT1 expression was significantly higher in Rb and BCa tissues than that in adjacent tissues. Functional assays revealed that RBAT1 accelerated tumorigenesis both in vitro and in vivo. Mechanistically, RBAT1 recruited HNRNPL protein to E2F3 promoter, thereby activating E2F3 transcription. Therapeutically, GapmeR-mediated RBAT1 silencing significantly inhibited tumorigenesis in orthotopic xenograft retinoblastoma models derived from Rb cell lines and Rb primary cells.

CONCLUSIONS

RBAT1 overexpression upregulates a known oncogene, E2F3, via directly recruiting HNPNPL to its promoter and cis-activating its expression. Our finding provides a novel mechanism of lncRNA biology and provides potential targets for diagnosis and treatment of Rb and BCa.

Long non-coding RNA CCDC144NL-AS1 sponges miR-143-3p and regulates MAP3K7 by acting as a competing endogenous RNA in gastric cancer

Gastric cancer (GC) has been one of the most leading cause of cancer-death worldwide. Long non-coding RNAs (lncRNAs) have been found to be related with the carcinogenesis and the development of various cancers, including GC. However, there are still many GC-related lncRNAs functional roles and molecular mechanisms that have not yet been clearly studied. Herein, we report lncRNA CCDC144NL-AS1, which has not been explored in GC, and it is markedly upregulated in GC tissues, which may serve as an independent predictor of poor prognosis. We found that CCDC144NL-AS1 expression was significantly positively associated with a larger tumor size and more pronounced lymph node metastasis. Through a series of in vivo and in vitro functional experiments, we observed that CCDC144NL-AS1 could facilitate cell proliferation, invasion and migration and inhibit cell apoptosis in GC. Further mechanism investigation revealed that CCDC144NL-AS1 acted as a competing endogenous RNA (ceRNA) for sponging miR-143-3p and upregulated the expression of its direct endogenous target MAP3K7 in GC. Taken together, our results elucidate the oncogenic roles of CCDC144NL-AS1/miR-143-3p/MAP3K7 axis in GC progression, providing inspiration for further understanding of the mechanism of GC and making CCDC144NL-AS1 as a potential novel diagnostic and therapeutic target for GC.

Long non-coding RNA POU6F2-AS2 promotes cell proliferation and drug resistance in colon cancer by regulating miR-377/BRD4

The aim of this study was to explore the molecular mechanism of lncRNA POU6F2‐AS2 in proliferation and drug resistance of colon cancer. Total paired 70 colon cancer and adjacent normal tissues were collected from colon cancer patients. Colon cancer and normal colonic epithelial cells were purchased. POU6F2‐AS2 was up‐ or down‐expressed by vectors. LC50 of all cell lines before and after transfection with these plasmids was detected. qRT‐PCR was used to detect the expression of POU6F2‐AS2, miR‐377 and BRD4 before or after transfection. In situ hybridization was also undertaken to detect the level of POU6F2‐AS2. Different concentrations of 5‐Fu (0, 1, 2.5, 5, 10, 20, 40 and 80 μg/mL) were used for 5‐FU insensitivity assay. CCK‐8 and crystal violet staining assay were used for detecting cell proliferation, and flow cytometry was used for identifying cell cycle distribution and apoptosis. In order to detect the fragmented DNA in apoptotic cells, TUNEL assay was used. RNA pull‐down assay and luciferase reporter assay were used to verify the binding site. Rescue assay confirmed the subtractive effect of miR‐377 inhibitors. POU6F2‐AS2 was highly expressed in colon cancer, which was associated with clinical pathology. Up‐regulated POU6F2‐AS2 promoted cell proliferation and cell cycle of colon cancer cells. Overexpression of POU6F2‐AS2 inhibited the expression of miR‐377 and then up‐regulated the expression of BRD4. Up‐regulated BRD4 ultimately promoted cell proliferation and cell survival Down‐regulated POU6F2‐AS2 showed enhanced sensitivity of 5‐FU. POU6F2‐AS2 promoted cell proliferation and drug resistance in colon cancer by regulating miR‐377/BRD4 gene.

CircPRMT5 circular RNA promotes proliferation of colorectal cancer through sponging miR-377 to induce E2F3 expression

CircPRTM5 is associated with cell proliferation and migration in many kinds of malignancies. However, the functions and mechanisms of CircPRTM5 in CRC progression remain unclear. We explored the role and the mechanisms of CircPRTM5 in the development of CRC. Tissues of CRC patients and matched adjacent non‐tumour tissues were collected to evaluate the expression of CircPRTM5. The expression of CircPRTM5 in CRC tissues was significantly higher than that in adjacent tissues. The biological functions of CircPRTM5 in CRC were determined by overexpression and down‐regulation of CircPRTM5 in CRC cells in vitro and in vivo. The results indicate that knockdown of CircPRTM5 can significantly inhibit the proliferation of CRC cells. The potential mechanisms of CircPRTM5 in CRC development were identified by RT‐qPCR, Western blotting analysis and luciferase reporter assay. CircPRTM5 competitively regulates the expression of E2F3 by capillary adsorption of miR‐377. CircPRMT5 regulates CRC proliferation by regulating the expression of E2F3, which affects the expression of the cell cycle‐associated proteins cyclinD1 and CDK2. CircPRTM5 exerts critical regulatory role in CRC progression by sponging miR‐377 to induce E2F3 expression.

Inhibition of endogenous miR-23a/miR-377 in CHO cells enhances difficult-to-express recombinant lysosomal sulfatase activity

Difficult-to-express (DTE) recombinant proteins such as multi-specific proteins, DTE monoclonal antibodies, and lysosomal enzymes have seen difficulties in manufacturability using Chinese hamster ovary (CHO) cells or other mammalian cells as production platforms. CHO cells are preferably used for recombinant protein production for their ability to secrete human-like recombinant proteins with posttranslational modification, resistance to viral infection, and familiarity with drug regulators. However, despite huge progress made in engineering CHO cells for high volumetric productivity, DTE proteins like recombinant lysosomal sulfatase represent one of the poorly understood proteins. Furthermore, there is growing interest in the use of microRNA (miRNA) to engineer CHO cells expressing DTE proteins to improve cell performance of relevant bioprocess phenotypes. To our knowledge, no research has been done to improve CHO cell production of DTE recombinant lysosomal sulfatase using miRNA. We identified miR-23a and miR-377 as miRNAs predicted to target SUMF1, an activator of sulfatases, using in silico prediction tools. Transient inhibition of CHO endogenous miR-23a/miR-377 significantly enhanced recombinant sulfatase enzyme-specific activity by ~15-21% compared to scramble without affecting cell growth. Though inhibition of miR-23a/miR-377 had no significant effect on the mRNA and protein levels of SUMF1, overexpression of miR-23a/377 caused ~30% and ~27-29% significant reduction in endogenous SUMF1 protein and mRNA expression levels, respectively. In summary, our data demonstrate the importance of using miRNA to optimize the CHO cell line secreting DTE recombinant lysosomal sulfatase.

Schistosomal extracellular vesicle-enclosed miRNAs modulate host T helper cell differentiation

During the chronic stage of Schistosoma infection, the female lays fertile eggs, triggering a strong anti-parasitic type 2 helper T-cell (Th2) immune response. It is unclear how this Th2 response gradually declines even though the worms live for years and continue to produce eggs. Here, we show that Schistosoma mansoni downregulates Th2 differentiation in an antigen-presenting cell-independent manner, by modulating the Th2-specific transcriptional program. Adult schistosomes secrete miRNA-harboring extracellular vesicles that are internalized by Th cells in vitro. Schistosomal miRNAs are found also in T helper cells isolated from Peyer's patches and mesenteric lymph nodes of infected mice. In T helper cells, the schistosomal miR-10 targets MAP3K7 and consequently downmodulates NF-κB activity, a critical transcription factor for Th2 differentiation and function. Our results explain, at least partially, how schistosomes tune down the Th2 response, and provide further insight into the reciprocal geographic distribution between high prevalence of parasitic infections and immune disorders such as allergy. Furthermore, this worm-host crosstalk mechanism can be harnessed to develop diagnostic and therapeutic approaches for human schistosomiasis and Th2-associated diseases.

Mirt2 functions in synergy with miR-377 to participate in inflammatory pathophysiology of Sjögren's syndrome

Background: The interaction of long non-coding RNAs (lncRNAs)-microRNAs (miRs) exerts crucial functions in mediating inflammatory reaction. It is still unclear whether myocardial infarction associated transcript 2 (Mirt2)-miR-377 mediates the inflammatory pathogenesis in Sjögren's syndrome (SS). Methods: The inflammatory lesion model was established by stimulating salivary gland epithelial cells (SGECs) by interferon gamma (IFN-γ). Mirt2- and/or miR-377-transfected SGECs, as well as their negative controls, were applied to investigate the biological functions in inflammation. Cell viability and apoptosis were examined using commercial kits. Western blot was applied to quantify protein level, and enzyme-linked immuno sorbent assay (ELISA) was used to value the secretion of cytokines. Results: The up-regulation of Mirt2 was observed in IFN-γ-treated SGECs. Mirt2 overexpression restored the expression of miR-377 which was repressed by IFN-γ. However, miR-377 silence abolished the protective effect on cell viability, inhibitory effect on apoptosis and prohibitive role in pro-inflammatory factors. Mirt2 diminished the phosphorylated expression of crucial regulators while miR-377 silence restored the phosphorylation in IFN-γ-treated SGECs. Conclusion: Mirt2 was elevated in IFN-γ-treated SGECs and then up-regulated miR-377 in response to inflammatory lesions. Mechanically, in synergy with miR-377 Mirt2 blocked IFN-γ-evoked activation of NF-κB and JAK/STAT signalling pathway.

MicroRNA-377 exerts a potent suppressive role in osteosarcoma through the involvement of the histone acetyltransferase 1-mediated Wnt axis

It has been demonstrated that microRNAs (miRNAs) may contribute to tumorigenesis and tumor growth in osteosarcoma (OS), which is a primary malignant tumor of bone frequently diagnosed in adolescents and young people. The purpose of our investigation was to evaluate the functional relevance of miR-377 in OS and to investigate whether the mechanism was related to the histone acetyltransferase 1 (HAT1)-mediated Wnt signaling pathway. By screening differentially expressed genes in microarray GSE47572, HAT1 was found to be a candidate gene of interest. Besides, the regulatory miRNA (miR-377) of HAT1 was also selected. The interaction among miR-377, HAT1, and the Wnt signaling pathway was evaluated. In addition, the miR-377 expression was altered in OS cells (U-2OS and SOSP-9607) to assess the in vitro cell apoptosis and the in vivo tumor growth. OS tissues presented elevated HAT1 expression and decreased miR-377 expression. A putative miR-377 binding site in HAT1 3'-UTR HAT1 was verified. Cells with miR-377 overexpression or HAT1 silencing were observed to exhibit reduced HAT1 expression and promoted apoptosis, accompanied by blockade of Wnt signaling. Moreover, the in vivo experiment revealed that miR-377 overexpression or HAT1 silencing inhibited tumor growth and reduced tumor size in nude mice. Taken together, our results conclude that miR-377 may promote OS cell apoptosis through inactivation of the HAT1-mediated Wnt signaling pathway, highlighting the potential therapeutic effect of miR-377 on OS treatment.

MiR-377 inhibits wear particle-induced osteolysis via targeting RANKL

Periprosthetic osteolysis caused by wear particles is the main factor that affects the long-term efficacy of artificial joint replacement, and macrophages play a vital role in the pathogenesis of periprosthetic osteolysis, while the potential mechanism underlying this is still unclear. To investigate the underlying role of miR-377 in wear particle-induced osteolysis (PIO), blood samples from patients undergoing arthroplasty were collected for analyzing the correlation between miR-377 expression and the clinicopathological parameters of PIO. Peripheral blood macrophages were obtained to compare the miR-377 and receptor activator of NF-κB ligand (RANKL) expressions. Bone marrow macrophages (BMMs) following titanium (Ti) particle treatment and/or miR-377 mimic transfection were used. The expressions of RANKL, pro-inflammatory cytokines interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α) and the osteoclast-related molecules tartrate-resistant acid phosphatase (TRAP) and cathepsin K (CTSK) were determined using real-time polymerase chain reaction or western blotting or enzyme-linked immunosorbent assay or TRAP staining, when appropriate. The interaction between miR-377 and RANKL was assessed by luciferase reporter assay. The in vivo role of miR-377 in PIO was evaluated using a mouse calvarial osteolysis model. There were significant differences in downregulated miR-377 expression between the different numbers of particles in the joint prostheses. The Ti particle treatment increased pro-inflammatory cytokine levels, downregulated RANKL and increased osteoclast activity in BMMs, while miR-377 overexpression led to the opposite effect. Taken together, miR-377 downregulated the target gene RANKL, resulting in PIO inhibition. MiR-377 relieved PIO by negatively regulating RANKL.

Role of miR-486-5p in regulating renal cell carcinoma cell proliferation and apoptosis via TGF-β-activated kinase 1

Renal cell carcinoma (RCC) is a common kidney tumor in adults. The role of miR-486-5p in RCC is unknown. The aim of our study was to identify new targets regulated by miR-486-5p in RCC, to obtain a deeper insight into the network and to better understand the role of these microRNAs and their targets in carcinogenesis of RCC. We performed a series of tests and found consistently lower expression levels of miR-486-5p in kidney cancer cells. Restoration of miR-486-5p expression in RCC cells could lead to the suppression of cell proliferation and the increase of cell apoptosis. Further studies demonstrated that TGF-β-activated kinase 1 was a target gene of miR-486-5p in kidney cancer cells. It was also shown that C-C motif chemokine ligand 2 (CCL2) from tumor-associated macrophages downregulated miR-486-5p expression, and miR-486-5p inhibited RCC cell proliferation and apoptosis resistance induced by CCL2. The study demonstrates that there are potential diagnosis and therapy values of miR-486-5p in RCC.

The long non-coding RNA SNHG5 regulates gefitinib resistance in lung adenocarcinoma cells by targetting miR-377/CASP1 axis

Gefitinib resistance is one of the major obstacles for the treatment of lung adenocarcinoma (LAD). The present study aimed to investigate the effects of the long non-coding RNA (lncRNA), small nucleolar RNA host gene 5SNHG5 on gefitinib resistance in LAD and explore the underlying mechanisms. The quantitative real-time PCR (qRT-PCR) results showed that SNHG5 expression was significantly down-regulated in LAD patients with acquired gefitinib resistance and gefitinib resistant LAD cell lines. SNHG5 overexpression sensitized gefitinib resistant LAD cells to gefitinib treatment, while knockdown of SNHG5 rendered gefitinib sensitive LAD cells to gefitinib treatment. Bioinformatics analysis showed that SNHG5 exerted its function through interaction with miR-377, which was further confirmed by luciferase reporter assay in 293T cells. Overexpression of SNHG5 suppressed the expression of miR-377, while the knockdown of SNHG5 increased the miR-377 expression. MiR-377 expression was significantly up-regulated in LAD specimens with acquired gefitinib resistance and was negatively correlated with SNHG5 expression. In addition, CASP1 was predicted as a downstream target of miR-377 Overexpression of miR-377 suppressed the expression of CASP1 in PC9 cells and knockdown of miR-377 increased the CASP1 expression in PC9GR cells. In vitro functional assay showed that knockdown of CASP1 in SNHG5-overexpressed PC9GR cells abolished their gefitinib resistance. Overall, the present study demonstrated, for the first time, that the SNHG5/miR-377/CASP1 axis functions as an important role in LAD cells gefitinib resistance and potentially contributes to the improvement of LAD diagnosis and therapy.

miR‑377 targets CUL4A and regulates metastatic capability in ovarian cancer

The incidence and recurrence rates of ovarian cancer are still high, and once the disease metastasizes, it is nearly always fatal. Cullin 4A (CUL4A) serves a significant role in tumourigenesis and tumour progression; however, the effect and mechanisms underlying CUL4A overexpression are still unknown. The role of microRNAs (miRs) in the regulation of metastatic capability in ovarian cancer cell lines was investigated. The interaction between miR‑377 and CUL4A was investigated using bioinformatics analyses and dual‑luciferase reporter assays. Furthermore, miR‑377 mRNA and protein levels were detected using reverse transcription‑quantitative polymerase chain reaction and western blotting, respectively and cell migration and invasion were detected using a Transwell assay. Results revealed that CUL4A expression was negatively associated with miR‑377 levels in ovarian cancer tissues and cell lines. Through in silico analysis, the targeting effect of miR‑377 on CUL4A was verified. Ectopic expression of miR‑377 in SKOV3 cells downregulated the level of CUL4A, and significantly reduced the migratory ability of the cells. miR‑377 overexpression led to reduced activity of the Wnt/β‑catenin signaling pathway, and regulated the expression of matrix metalloproteinase‑2, and 9, and epithelial‑mesenchymal transition (EMT)‑associated protein. These results suggested that miR‑377 is a significant negative regulator of CUL4A that controls cancer cell progression in ovarian cancer cell lines.

Differential Expression of MicroRNAs in Uterine Cervical Cancer and Its Implications in Carcinogenesis; An Integrative Approach

Objectives

Cervical cancer is the second most common cancer in women in developing countries, including India. Recently, microRNAs (miRNAs) are gaining importance in cancer biology because of their involvement in various cellular processes. The present study aimed to profile miRNA expression pattern in cervical cancer, identify their target genes, and understand their role in carcinogenesis.

Methods

Human papillomavirus (HPV) infection statuses in samples were assessed by heminested polymerase chain reaction followed by direct DNA sequencing. Next-generation sequencing and miRNA microarray were used for miRNA profiling in cervical cancer cell lines and tissue samples, respectively. MicroRNA signature was validated by quantitative real-time PCR, and biological significance was elucidated using various in silico analyses.

Results

Cervical cancer tissues samples were mostly infected by HPV type 16 (93%). MicroRNA profiling showed that the pattern of miRNA expression differed with respect to HPV positivity in cervical cancer cell lines. However, target and pathway analyses indicated identical involvement of these significantly deregulated miRNAs in HPV-positive cervical cancer cell lines irrespective of type of HPV infected. Microarray profiling identified a set of miRNAs that are differentially deregulated in cervical cancer tissue samples which were validated using quantitative real-time PCR. In silico analyses revealed that the signature miRNAs are mainly involved in PI3K-Akt and mTOR pathways.

Conclusions

The study identified that high-risk HPV induces similar carcinogenic mechanism irrespective of HPV type. The miRNA signature of cervical cancer and their target genes were also elucidated, thereby providing a better insight into the molecular mechanism underlying cervical cancer development.

The ten-year evolutionary trajectory of a highly recurrent paediatric high grade neuroepithelial tumour with MN1:BEND2 fusion

Astroblastomas are rare brain tumours which predominate in children and young adults, and have a controversial claim as a distinct entity, with no established WHO grade. Reports suggest a better outcome than high grade gliomas, though they frequently recur. Recently, they have been described to overlap with a newly-discovered group of tumours described as'high grade neuroepithelial tumour with MN1 alteration' (CNS HGNET-MN1), defined by global methylation patterns and strongly associated with gene fusions targeting MN1. We have studied a unique case of astroblastoma arising in a 6 year-old girl, with multiple recurrences over a period of 10 years, with the pathognomonic MN1:BEND2 fusion. Exome sequencing allowed for a phylogenetic reconstruction of tumour evolution, which when integrated with clinical, pathological and radiological data provide for a detailed understanding of disease progression, with initial treatment driving tumour dissemination along four distinct trajectories. Infiltration of distant sites was associated with a later genome doubling, whilst there was evidence of convergent evolution of different lesions acquiring distinct alterations targeting NF-κB. These data represent an unusual opportunity to understand the evolutionary history of a highly recurrent childhood brain tumour, and provide novel therapeutic targets for astroblastoma/CNS HGNET-MN1.

The regulation and function of microRNA-377/RASSF8 signaling axis in gastric cancer

Gastric cancer is a major cause of cancer-associated mortality worldwide. The aberrant expression of microRNA (miRNA) is involved in tumorigenesis. Ras proteins transfer information from the extracellular environment to internal cellular compartments and are essential in numerous signal transduction pathways. To investigate the regulation, function and clinical significance of the miRNA377/Ras association domain family (RASSF) 8 signaling axis in gastric cancer, reverse transcription-quantitative polymerase chain reaction, immunohistochemistry, cell counting kit-8, western blotting, and Transwell assays were used. The results revealed that expression of RASSF8 was significantly upregulated in normal gastric tissues compared with gastric cancer, which was further confirmed by immunohistochemical analysis, and its expression level was increased in normal gastric cells compared with gastric cancer cell lines. However, the expression of miR-377 was significantly upregulated in gastric cancer compared with normal gastric tissues. In addition, RASSF8 overexpression in BGC-823 gastric cancer cells significantly inhibited the proliferation, apoptosis and invasive abilities of cells. Whereas miR-377 attenuated these effects due to downregulated RASSF8 expression by directly targeting its 3′-untranslated region. Furthermore, in the current study, miR-377 was not able to reverse the effects of RASSF8 overexpression on gastric cancer cells. Collectively, the RASSF8 gene may represent a novel molecular target involved in gastric cancer development and may be useful in targeted therapy of patients with gastric cancer.

Resveratrol suppresses melanoma by inhibiting NF-κB/miR-221 and inducing TFG expression

Resveratrol (Res) is a natural compound with anti-cancer effects. The goal of this study is to evaluate the suppression of Res in melanoma and investigate its relationship with miRNAs during this process. The in vitro and in vivo anti-cancer abilities of Res were evaluated using cellular assays and animal model. Two melanoma cell lines (A375 and MV3) were used for both in vitro assay and in vivo experiments. qRT-PCR and Western blot were used to detect the changes in gene expressions and protein levels. Dual-luciferase reporter assay and bioinformatic tools were used to further confirm the protein binding and activation of targeted genes. In vitro experiments showed Res significantly decreased the expression of miR-221, an oncogenic microRNA, which was confirmed by the overexpression of miR-221 with or without Res treatment. Mechanistically, we showed that the inhibition of miR-221 by Res was achieved by regulating NF-κB (RELA) activity. In the meantime, we also identified that TFG, a tumor suppressor gene, was a target of miR-221. Finally, using in vivo melanoma model, we confirmed the tumor suppressive effects of Res and our in vitro regulatory network. Res displayed a significant anti-tumor effect on melanoma cells both in vitro and in vivo. The cellular mechanism under this effect involves miRNA regulation.

Alterations of microRNAs throughout the malignant evolution of cutaneous squamous cell carcinoma: the role of miR-497 in epithelial to mesenchymal transition of keratinocytes

Skin carcinogenesis is known to be a multi-step process with several stages along its malignant evolution. We hypothesized that transformation of normal epidermis to cutaneous squamous cell carcinoma (cSCC) is causally linked to alterations in microRNAs (miRNA) expression. For this end we decided to evaluate their alterations in the pathologic states ending in cSCC. Total RNA was extracted from formalin fixed paraffin embedded biopsies of five stages along the malignant evolution of keratinocytes towards cSCC: Normal epidermis, solar elastosis, actinic keratosis KIN1-2, advanced actinic keratosis KIN3 and well-differentiated cSCC. Next-generation small RNA sequencing was performed. We found that 18 miRNAs are overexpressed and 28 miRNAs are underexpressed in cSCC compared to normal epidermis. miR-424, miR-320, miR-222 and miR-15a showed the highest fold change among the overexpressed miRNAs. And miR-100, miR-101 and miR-497 showed the highest fold change among the underexpressed miRNAs. Heat map of hierarchical clustering analysis of significantly changed miRNAs and principle component analysis disclosed that the most prominent change in miRNAs expression occurred in the switch from 'early' stages; normal epidermis, solar elastosis and early actinic keratosis to the 'late' stages of epidermal carcinogenesis; late actinic keratosis and cSCC. We found several miRNAs with 'stage specific' alterations while others display a clear 'gradual', either progressive increase or decrease in expression along the malignant evolution of keratinocytes. The observed alterations focused in miRNAs involved in the regulation of AKT/mTOR or in those involved in epithelial to mesenchymal transition. We chose to concentrate on the evaluation of the molecular role of miR-497. We found that it induces reversion of epithelial to mesenchymal transition. We proved that SERPINE-1 is its biochemical target. The present study allows us to further study the pathways that are regulated by miRNAs along the malignant evolution of keratinocytes towards cSCC.

Regulator of G protein signaling 4 inhibits human melanoma cells proliferation and invasion through the PI3K/AKT signaling pathway

Melanoma is a tumor produced by skin melanocytes, which has a high metastatic rate and poor prognosis. So far, plenty of work has been done on melanoma, but mechanisms underlying melanoma development have not been fully elucidated. Here we identified regulator of G protein signaling 4(RGS4) as novel therapeutic target for malignant melanoma and its regulating effect on melanoma. We found that endogenous RGS4 expression was much lower in melanoma tissues and cells. In A375 cell line with low endogenous RGS4 expression, the function of RGS4 was detected by up-regulation its expression with pcDNA3.1-RGS4 and knockdown its expression with siRNA. Our results showed that RGS4 could significantly reduce the proliferation, migration and invasion of melanoma cells. RGS4 is an important regulator for the apoptosis of melanocyte, and the apoptosis rate is significantly decreased in low RGS4 enviroment. RGS4 induced non-activation of PI3K/AKT pathway, resulting in decreased expression of E2F1 and Cyclin D1, thus constraining cell proliferation and invasion. These results were further confirmed in M14 cell lines. Collectively, our findings show that RGS4 plays an important role in multiple cellular functions of melanoma development and is valuable to be a therapeutic target.

MiR-377 promotes white adipose tissue inflammation and decreases insulin sensitivity in obesity via suppression of sirtuin-1 (SIRT1)

Obesity is associated with a wide range of metabolic disorders including inflammation and insulin-resistance. Sirtuin-1 (SIRT1) is an important regulator of metabolic homeostasis and stress response pathways in white adipose tissue. However, involvement of microRNAs (miRNAs) in regulating SIRT1 during obesity-induced inflammation and insulin-resistance remains unclear. Here, we found that miR-377 was upregulated in adipose tissue and showed a negative correlation with SIRT1 in chronic high fat diet (HFD)-fed mice. MiR-377 belongs to a large miRNA cluster and functions as an important tumor suppressor in several human malignancies. Recently, it has also gained considerable attention in oxidative stress and diabetic nephropathy. In our present study, we found that overexpression of miR-377 decreased SIRT1 protein abundance and caused inflammation and insulin-resistance in differentiated 3T3-L1 cells. Conversely, miR-377 inhibition increased SIRT1 mRNA and protein levels, ameliorated inflammation and improved insulin sensitivity. Furthermore, we demonstrated that miR-377 targets the 3′-UTR of SIRT1 mRNA directly, and downregulates SIRT1 protein abundance. Inhibition of SIRT1 by EX527 significantly eliminated the downregulation of the inflammation and insulin-resistance levels induced by the miR-377 inhibitor. Furthermore, SIRT1 deficiency intensified adipose tissue inflammation and insulin-resistance, resulting in hepatic steatosis in chronic-HFD-fed mice. In conclusion, our findings suggest that miR-377 promotes white adipose tissue inflammation and decreases insulin sensitivity in obesity, at least in part, through suppressing SIRT1.

SOX4 promotes melanoma cell migration and invasion though the activation of the NF-κB signaling pathway

SOX4 has been reported to be abnormally expressed in many types of cancer, including melanoma. However, its role in cell proliferation and metastasis remains controversial. In this study, SOX4 was downregulated or overexpressed in A375, A2058 and A875 melanoma cells by siRNA or lentivirus transfection, respectively. Cell metastasis was observed by Transwell assay. In an aim to elucidate the underlying mechanisms, we determined the expression of nuclear factor-κB (NF-κB) by real-time PCR assay and western blot analysis. Our data indicated that SOX4 knockdown inhibited melanoma cell migration and invasion. In the melanoma cells in which SOX4 was downregulated, the expression levels of NF-κB/p65, matrix metalloproteinase (MMP)2 and MMP9 were suppressed at both the mRNA and protein levels. Conversely, the overexpression of SOX4 promoted melanoma cell migration and invasion. In the melanoma cells in which SOX4 was overexpressed, the expression levels of NF-κB/p65, MMP2 and MMP9 were increased at both the mRNA and protein level. On the whole, our findings indicate that SOX4 promotes melanoma cell migration and invasion through the activation of the NF-κB/p65 signaling pathway. Thus, SOX4 may prove to be a potential therapeutic target for the treatment of melanoma.

MiRNAs and E2F3: a complex network of reciprocal regulations in human cancers

E2F transcription factor 3 (E2F3) is oncogenic in tumorigenesis. Alterations in E2F3 functions correspond with poor prognosis in various cancers, underscoring their status for the clinical cancer phenotype. Latest reports discovered intricate networks between microRNAs (miRNAs) and E2F3 in regulating the balance of these events, including proliferation, apoptosis, metastasis, as well as drug resistance. miRNAs are non-coding small RNAs which negatively regulate gene expressions post-transcriptionally mainly through 3′-UTR binding of target mRNAs. Increasing evidence shows that E2F3 can be activated/inhibited by numerous miRNAs whose dysregulation has been implicated in malignancy. In turn, miRNAs themselves can be transcriptionally regulated by E2F3, thus forming a negative feedback loop. These findings add a new challenging layer of complexity to E2F3 network. Current understanding of the reciprocal link between E2F3 and miRNAs in human cancers were summarized, which could help to develop potential therapeutic strategies.

MiR-143 Targeting TAK1 Attenuates Pancreatic Ductal Adenocarcinoma Progression via MAPK and NF-κB Pathway In Vitro

BACKGROUND

Transforming growth factor (TGF)-β-activated kinase 1 (TAK1) is one of the major regulators of inflammation-induced cancer cell growth and progression. MiR-143 dysregulation is a common event in a variety of human diseases including pancreatic ductal adenocarcinoma (PDA).

AIMS

To identify the interaction between TAK1 and miR-143 in PDA.

METHODS

Data mining of TAK1 expression in PDA patient gene profiling was conducted. QRT-PCR and western blot were performed to detect the expression of TAK1 in PDA tissues and cell lines. Ectopic miR-143 and TAK1 were introduced to PDA cells. Cell growth, apoptosis and migration were examined. Xenograft models were used to examine the function of TAK1 in vivo. Western blot and luciferase assay were carried out to investigate the direct target of miR-143.

RESULTS

PDA patient gene profiling data (GSE15471 and GSE16515) showed that TAK1 mRNA was aberrantly up-regulated in PDA tissues. TAK1 protein levels were overexpressed in PDA tissues and cell lines. Overexpression of TAK1 was strongly associated with positive lymph node metastasis. Inhibition of TAK1 suppressed cell growth, migration, and induced cell apoptosis in vitro and in vivo. Further studies demonstrated that TAK1 was a direct target gene of miR-143. MiR-143 also inhibited PDA cells proliferation and migration, induced apoptosis and G₁/S arrest. Moreover, TAK1 depletion inactivated MAPK and NF-κB pathway, mimicking the function of miR-143.

CONCLUSIONS

The study highlights that miR-143 acts as a tumor suppressor in PDA through directly targeting TAK1, and their functional regulation may provide potential therapeutic strategies in clinics.

Effects of miR-145-5p through NRAS on the cell proliferation, apoptosis, migration, and invasion in melanoma by inhibiting MAPK and PI3K/AKT pathways

We aimed to detect the effects of miR-145-5p on the cell proliferation, apoptosis, migration, and invasion in NRAS-mutant, BRAF-mutant, and wild-type melanoma cells, in order to figure out the potential mechanisms and provide a novel therapeutic target of melanoma. RT-qPCR and western blot were used to detect the expression of miR-145-5p and NRAS in melanoma tumor tissues and cells, respectively. Luciferase assay was performed to determine whether miR-145-5p directly targeted NRAS. After transfecting miR-145-5p mimics, miR-145-5p inhibitors, NRAS cDNA and NRAS siRNA into CHL-1, VMM917 and SK-mel-28 cells, functional assays were used to detect the proliferation, apoptosis, invasion and migration, including MTT, flow cytometry, Transwell and wound healing assays. In addition, xenograft models in nude mice were also conducted to verify the role of miR-145-5p in vivo. MiR-145-5p was able to suppress proliferation, invasion, and migration of VMM917 and CHL-1 cells and induce apoptosis by inhibiting MAPK and PI3K/AKT pathways. However, aberrant expression of miR-145-5p and NRAS has little impact on the viability and metastasis of BRAF-mutant melanoma. The higher expression of miR-145-5p in xenograft models repressed the VMM917-induced and CHL-1-induced tumor growth observably and has little effect on SK-mel-28-induced tumor growth which was consistent with the results in vitro. Through targeting NRAS, miR-145-5p could suppress cell proliferation, invasion, and migration and induce apoptosis of CHL-1 and VMM917 melanoma cells by inhibiting MAPK and PI3K/AKT pathways.