miR-137 plays tumor suppressor roles in gastric cancer cell lines by targeting KLF12 and MYO1C

A noncanonical E3 ubiquitin ligase RNF41-mediated MYO1C stability promotes prostate cancer metastasis by inducing actin remodeling

Prostate cancer bone metastasis is a predominant cause of death for prostate cancer (PCa) patients. However, the underlying mechanisms are poorly understood. Here, we report that high levels of RNF41 are associated with metastatic human prostate cancer. RNF41 silencing inhibits prostate cancer cell growth, cell migration and invasion in vitro and in vivo. Mechanistically, we identify that RNF41 induces K27- and K63-linked noncanonical polyubiquitination of MYO1C to enhance its stability and induce actin remodeling, which promotes PCa bone metastasis. RNF41 was significantly upregulated in metastatic prostate cancer tissues and positively associated with MYO1C expression. Furthermore, we show in intraarterial injected-bone metastasis xenograft model that targeting MYO1C stability by inhibition of RNF41 markedly suppressed PCa bone metastasis. Collectively, our findings identify RNF41 is an important regulator of prostate cancer cell growth and metastasis and targeting RNF41/MYO1C could be a valuable strategy to ameliorate prostate cancer progression and metastasis.

Zinc Finger Proteins in the War on Gastric Cancer: Molecular Mechanism and Clinical Potential

According to the 2020 global cancer data released by the World Cancer Research Fund (WCRF) International, gastric cancer (GC) is the fifth most common cancer worldwide, with yearly increasing incidence and the second-highest fatality rate in malignancies. Despite the contemporary ambiguous molecular mechanisms in GC pathogenesis, numerous in-depth studies have demonstrated that zinc finger proteins (ZFPs) are essential for the development and progression of GC. ZFPs are a class of transcription factors with finger-like domains that bind to Zn²⁺ extensively and participate in gene replication, cell differentiation and tumor development. In this review, we briefly outline the roles, molecular mechanisms and the latest advances in ZFPs in GC, including eight principal aspects, such as cell proliferation, epithelial-mesenchymal transition (EMT), invasion and metastasis, inflammation and immune infiltration, apoptosis, cell cycle, DNA methylation, cancer stem cells (CSCs) and drug resistance. Intriguingly, the myeloid zinc finger 1 (MZF1) possesses reversely dual roles in GC by promoting tumor proliferation or impeding cancer progression via apoptosis. Therefore, a thorough understanding of the molecular mechanism of ZFPs on GC progression will pave the solid way for screening the potentially effective diagnostic indicators, prognostic biomarkers and therapeutic targets of GC.

Class I Myosins, molecular motors involved in cell migration and cancer

Class I Myosins are a subfamily of motor proteins with ATPase activity and a characteristic structure conserved in all myosins: A N-Terminal Motor Domain, a central Neck and a C terminal Tail domain. Humans have eight genes for these myosins. Class I Myosins have different functions: regulate membrane tension, participate in endocytosis, exocytosis, intracellular trafficking and cell migration. Cell migration is influenced by many cellular components including motor proteins, like myosins. Recently has been reported that changes in myosin expression have an impact on the migration of cancer cells, the formation of infiltrates and metastasis. We propose that class I myosins might be potential markers for future diagnostic, prognostic or even as therapeutic targets in leukemia and other cancers.Abbreviations: Myo1g: Myosin 1g; ALL: Acute Lymphoblastic Leukemia, TH1: Tail Homology 1; TH2: Tail Homology 2; TH3: Tail Homology 3.

miR-2682-3p antagonizes its host lncRNA-MIR137HG by interacting with the same target FUS to regulate the progression of gastric cancer

Background

The mechanism of long non-coding RNA MIR137HG in human gastric cancer (GC) is currently unknown. In the present study, we aimed to explore the function and mechanism of MIR137HG in gastric cancer.

Methods

The expression of lncRNA-MIR137HG in 69 gastric cancer samples and their paired surgical margin (SM) tissue samples were tested by QRT-PCR. UCSC was used to find the gene location relationship among MIR137HG and its embedded miRNAs. TargetScan was used to predict the targets of miR-2682-3p. Starbase was used to predict the candidate proteins that interacted with MIR137HG. Western blot, co-focus, and RIP assay were used to verify the direct interaction between MIR137HG and FUS (fused in sarcoma/translocated in liposarcoma, FUS/TLS), while dual-luciferase reporter assay was used to confirm the interaction between miR-2682-3p and FUS. Cell migration assays, colony formation, and xenografts assay were used to investigate the function of MIR137HG and miR-2682-3p to tumor growth and metastasis. Western blot assay was used to explore the downstream candidate protein of FUS.

Results

Data showed that MIR137HG expressed significantly higher in GC than in SM. MIR137HG promoted colony formation and migration in vitro and promoted tumor formation and metastasis in vivo. MIR137HG is distributed in both the nucleus and cytoplasm. It was co-located with FUS and could directly interact with FUS, which might interact with other proteins, such as MET(MET-proto-oncogene, receptor tyrosine kinase), RHOC(ras homolog family member), and CTNNB1(catenin beta1). These proteins may involve different signaling pathways to regulate gastric cancer progression. By contrast, the embedded miR-2682-3p could antagonize the series functions of its host lncRNA-MIR137HG by targeting FUS.

Conclusions

lncRNA-MIR137HG promoted growth and metastasis in gastric cancer by interacting with FUS, while miR-2682-3p could inhibit the function of MIR137HG via the same target FUS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09740-9.

Significant Association of Variable Number Tandem Repeat Polymorphism rs58335419 in the MIR137 Gene With the Risk of Gastric and Colon Cancers

The purpose of the article: The MIR137 gene acts as a tumor-suppressor gene in colon and gastric cancers. The aim of this study was to investigate the association of functional variable number tandem repeat (VNTR) polymorphism rs58335419 locating in the upstream of the MIR137 gene with the risk of colon and gastric cancers.

Materials and methods: Totally, 429 individuals were contributed in the study, including 154 colon and 120 gastric cancer patients and 155 healthy controls. The target VNTR was genotyped using PCR and electrophoresis for all samples. Statistical analysis was performed using SPSS 21.0 software and by T, χ2 and logistic regression tests.

Results: Excluding the rare genotypes, our results showed that genotype 3/5 (95% CI = 1.08–3.73, OR = 2.01, p = 0.026) significantly increased the risk of colon cancer but not gastric cancer (95% CI = 0.88–3.30, OR = 1.70, p = 0.114). Also, in the stratification analysis for VNTRs and sex, genotypes 3/4 (95% CI = 1.00–6.07, OR = 2.46, p = 0.049) and 3/5 (95% CI = 1.25–7.18, OR = 2.99, p = 0.014) significantly increased the risk of colon cancer in men but not in women. In addition, all genotypes including the rare genotypes as a group, significantly increase the risk of gastric (95% CI = 1.14–3.00, OR = 1.85, p = 0.012) and colon (95% CI = 1.38–3.43, OR = 2.17, p = 0.001) cancers compared to the genotype 3/3 as a reference.

Conclusion: The results show that increasing the copy of VNTR in the MIR137 gene, increases the risk of colon and gastric cancers and can serve as a marker for susceptibility to colon and gastric cancers.

Long non-coding RNA p53 upregulated regulator of p53 levels (PURPL) promotes the development of gastric cancer

Gastric cancer (GC), one of the most prevalent malignancies across the world, has an increasing incidence rate. Long non-coding RNA (lncRNA) PURPL (also referred to as LINC01021) has been demonstrated to influence malignant GC behaviors and partake in other cancers. Notwithstanding, reports pertaining to the underlying mechanism of PURPL in GC haven’t been rarely seen. Presently, in-vivo and ex-vivo experiments were implemented to examine the PURPL-miR-137-ZBTB7A-PI3K-AKT-NF-κB regulatory axis in GC. Our statistics revealed that PURPL presented a high expression in GC tissues and cell lines. PURPL overexpression remarkably exacerbated colony formation, migration, and invasion and repressed apoptosis in GC cells (AGS and MNK-45). In-vivo experiments also corroborated that cell growth was boosted by PURPL up-regulation. Mechanistic investigations verified that PURPL interacted with miR-137 and lowered its profile in GC cell lines. miR-137 overexpression or ZBTB7A knockdown upended the oncogenic function mediated by PURPL. PURPL initiated the PI3K/AKT/NF-κB pathway. PI3K and NF-κB inhibition impaired the promoting impact on GC cells elicited by PURPL overexpression and contributed to PURPL down-regulation. These findings disclosed that PURPL serves as an oncogene in the context of GC via miR-137-ZBTB7A-PI3K-AKT-NF-κB axis modulation.

lncRNA DSCR8 mediates miR-137/Cdc42 to regulate gastric cancer cell proliferation, invasion, and cell cycle as a competitive endogenous RNA

lncRNA DSCR8 (Down syndrome critical region 8) is involved in progression of many cancers, but its specific role in gastric cancer (GC) is still unclear. Here, qRT-PCR detected upregulated expression of DSCR8 and Cdc42 and downregulated expression of miR-137 in GC. The protein expression level of Cdc42 in GC was upregulated as tested by western blot. Statistical analysis showed that DSCR8 was closely associated with some malignant clinicopathological features (such as tumor size, metastasis, and stage) in GC patients. Fluorescence in situ hybridization showed that DSCR8 was localized in the nucleus and cytoplasm. Dual-luciferase reporter gene, RNA immunoprecipitation, and biotin pull-down assays showed that DSCR8 could bind to miR-137 could bind to Cdc42. In vitro and in vivo assays showed that DSCR8 could promote proliferation, invasion, and the cycle of GC cells and inhibit cell apoptosis. In addition, a rescue experiment showed that DSCR8 regulated progression of GC cells via miR-137. Furthermore, DSCR8 regulated Cdc42 in GC cells by inhibiting miR-137. Taken together, these data indicated that DSCR8 could adsorb miR-137 to reduce its inhibitory effect on Cdc42 expression, thereby promoting the progression of GC cells and regulating the cell cycle. These results provide a novel direction for DSCR8 as a target of GC.

Suppression of ANT2 by miR-137 Inhibits Prostate Tumorigenesis

Prostate cancer (PCa) is a serious disease that affects men’s health. To date, no effective and long-lasting treatment option for this condition is available in clinical practice. ANT2 is highly expressed in a variety of hormone-related cancers, but its relationship and regulatory mechanism with PCa are unclear. In this study, we found that ANT2 expression was significantly upregulated in PCa tissues relative to control samples. Genetic knockdown of ANT2 effectively inhibited, while overexpression promoted, proliferation, migration, and invasion of PCa cells. In addition, miR-137 expression was reduced in prostate cancer tissues relative to control tissues. We identified a regulatory site for miR-137 in the 3′-UTR of ANT2 mRNA; luciferase reporter assays indicated that ANT2 is a direct target gene for miR-137. Transfecting cells with miR-137 mimics and/or an ANT2-encoding plasmid revealed that ANT2 promotes proliferation, migration, and invasion of PCa, whereas co-expression of miR-137 mimics inhibited these behaviors. These observations suggest that miR-137 mimics inhibit development of PCa by antagonizing expression of ANT2. Furthermore, tumorigenic assays in nude mice showed that miR-137 inhibitors abolished the inhibitory effect of ANT2 knockdown on PCa tumor growth. Collectively, our findings suggest that ANT2, a target gene of miR-137, is intimately involved in development of PCa, providing new evidence for the mechanism underlying pathogenesis of PCa as well as new options for targeted therapy.

Integrated analysis of Solute carrier family-2 members reveals SLC2A4 as an independent favorable prognostic biomarker for breast cancer

Most of Solute carrier family-2 (SLC2) members play a key role of facilitative transporters, and glucose transporter (GLUT) proteins encoded by SLC2s can transport hexoses or polyols. However, the function and mechanism of SLC2s remain unclear in human cancers. Here, we explored the dysregulated expression, prognostic values, epigenetic, genetic alterations, and biomolecular network of SLC2s in human cancers. According to the data from public-omicsrepository, SLC2A4 (GLUT4) was found to be significantly downregulated in most cancers, and higher messenger RNA (mRNA) expression of SLC2A4 significantly associated with better prognosis of breast cancer (BRCA) patients. Moreover, DNA hypermethylation in the promoter of SLC2A4 may affect the regulation of its mRNA expression, and SLC2A4 was strongly correlated with pathways, including the translocation of SLC2A4 to the plasma membrane and PID INSULIN PATHWAY. In conclusion, these results provide insight into SLC2s in human cancers and suggest that SLC2A4 could be an unfavorable prognostic biomarker for the survival of BRCA patients.

Circ-RNF111 aggravates the malignancy of gastric cancer through miR-876-3p-dependent regulation of KLF12

Background

The aberrant expression of circular RNAs (circRNAs) plays vital roles in the advancement of human cancers, including gastric cancer (GC). In this study, the functions of circRNA ring finger protein 111 (circ-RNF111) in GC were investigated.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) assay was performed for the levels of circ-RNF111, microRNA-876-3p (miR-876-3p) and krueppel-like factor 12 (KLF12) mRNA. RNase R assay was conducted for the feature of circ-RNF111. Cell Counting Kit-8 (CCK-8) assay, colony formation assay, wound-healing assay, and transwell assay were applied for cell viability, colony formation, migration, and invasion, respectively. Flow cytometry analysis was used to analyze cell apoptosis and cell cycle process. The glycolysis level was examined using specific commercial kits. Western blot assay was carried out to measure the protein levels of hexokinase 2 (HK-2) and KLF12. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were employed to verify the combination between miR-876-3p and circ-RNF111 or KLF12. Murine xenograft model was constructed for the role of circ-RNF111 in vivo. Immunohistochemistry (IHC) was used for KLF12 level.

Results

Circ-RNF111 was higher expressed in GC tissues and cells than normal tissues and cells. Silencing of circ-RNF111 restrained cell viability, colony formation, migration, invasion, cell cycle process and glycolysis and induced apoptosis in GC cells in vitro. Circ-RNF111 positively regulated KLF12 expression via absorbing miR-876-3p. MiR-876-3p downregulation reversed the impacts of circ-RNF111 silencing on GC cell malignant phenotypes. MiR-876-3p overexpression repressed GC cell growth, metastasis and glycolysis, inhibited apoptosis and arrested cell cycle, while KLF12 elevation weakened the effects. Besides, circ-RNF111 knockdown inhibited tumor growth in vivo.

Conclusion

Circ-RNF111 knockdown relieved the development of GC by regulating miR-876-3p/KLF12 axis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02373-5.

Prognostic Value of miR-137 in Children with Medulloblastoma and its Regulatory Effect on Tumor Progression

Medulloblastoma is a malignant tumor with high incidence and poor prognosis in adolescents and children. MicroRNA-137 (miR-137) has been found to be abnormally expressed in cancers such as pancreatic cancer. The purpose of this study is to explore the expression of miR-137 in MB and its role in cell physiological activities to determine the significance of miR-137 in the prognosis of MB. First, the expression of miR-137 in MB tissues and cell lines was analyzed by qRT-PCR. Then the Kaplan-Meier survival curve was used to analyze the significance of miR-137 expression in the prognosis, and the Cox regression model was used to explore the correlation between miR-137 expression and clinical characteristics. The effects of miR-137 on MB cell activities were analyzed by MTT assay, Transwell assays, and flow cytometry. It can be concluded from the results that the expression of miR-137 is down-regulated in MB tissues and cells. The down-regulation of miR-137 was significantly related to the poor prognosis of MB, and significantly related to clinical indicators. Up-regulated miR-137 inhibited cell proliferation, migration, invasion, and cell cycle progression, as well as induced cell apoptosis by targeting KDM1A. This study can conclude that miR-137 may be used as a prognostic biomarker of MB.

Circular RNA circHECTD1 prevents Diosbulbin-B-sensitivity via miR-137/PBX3 axis in gastric cancer

Backgrounds

Gastric cancer (GC) is general disease in human digestive system with malignancy. Emerging findings indicated that hsa_circ_0031452 (circHECTD1) was strictly associated with carcinogenesis. Nevertheless, the role of circHECTD1 in drug-resistance still needed to be explained.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to examine the expression profiles of circHECTD1, microRNA (miR)-137, and pre-leukemia transcription factor 3 (PBX3). The function of circHECTD1 in tumorigenesis was evaluated via xenograft tumor model. The IC₅₀ of Diosbulbin-B (DB) was detected using Cell Counting Kit-8 (CCK8). Cell-cycle and apoptosis were reckoned by flow cytometry. Besides, western blot was administrated to reckon the levels of PBX3 and cell apoptotic indicators. Moreover, the interrelation between miR-137 and circHECTD1 or PBX3 was expounded by dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull down assays.

Results

We uncovered that circHECTD1 was ectopically up-regulated in GC tissues and cells. CircHECTD1 deficiency sensitized DB-treatment in DB-evoked AGS and HGC-27 cells. In vivo assay, circHECTD1 silencing led to the tumor reduction. Also, circHECTD1 served as miR-137 sponge in a sequence-complementary manner. Furthermore, transfection of miR-137 inhibitor markedly eliminated circHECTD1 absence-mediated promotion of DB-sensitivity in GC cells. Moreover, PBX3, a target of miR-137, play a DB-resistant role in GC cells. Fascinatingly, the deletion of PBX3 reversed the impact of miR-137 repression and circHECTD1 knockdown on DB-sensitivity in vitro.

Conclusions

CircHECTD1 served as an oncogene by a novel miR-137/PBX3 axis, which might supply an underlying biomarker for the diagnosis and prognosis of GC management.

Depletion of Circular RNA circ_CORO1C Suppresses Gastric Cancer Development by Modulating miR-138-5p/KLF12 Axis

Background

Gastric cancer (GC) is a common and deadly malignancy in the world. CircRNAs have emerged as important regulators in human diseases, including GC. In this work, we intended to explore the role of circ_CORO1C in GC progression and potential mechanism.

Methods

Quantitative real-time PCR (qRT-PCR) or Western blot assay was performed to examine the expression of circRNA coronin-like actin-binding protein 1C (circ_CORO1C), microRNA (miR)-138-5p and Krueppel-like factor 12 (KLF12) in clinical samples and cells. Cell colony formation ability and viability were measured by colony formation assay and methyl thiazolyl tetrazolium (MTT) assay, respectively. Expression of cell proliferation and epithelia-mesenchymal transition (EMT) biomarker was detected by Western blot analysis. And cell metastasis, including migration and invasion, and apoptosis were analyzed via Transwell assay and flow cytometry, respectively. Target relationship among circ_CORO1C, miR-138-5p and KLF12 was validated by dual-luciferase reporter assay. The in vivo role of circ_CORO1C was investigated by tumor xenograft assay.

Results

Circ_CORO1C and KLF12 were upregulated, while miR-138-5p was downregulated in GC tissues and cells. Circ_CORO1C knockdown suppressed colony formation ability, viability, migration, invasion and EMT in GC cells, while promoted cell apoptosis in vitro. Circ_CORO1C targeted miR-138-5p, the inhibition of which could attenuate silenced circ_CORO1C-induced inhibitory effects on GC progression. MiR-138-5p repressed the aggressive malignant behaviors of GC cells by directly targeting KLF12. Circ_CORO1C deficiency inhibited GC tumor growth in vivo.

Conclusion

Depletion of circ_CORO1C suppressed GC progression by regulating miR-138-5p/KLF12 axis, offering a potential molecular target for GC therapy.

Atrx Deletion in Neurons Leads to Sexually Dimorphic Dysregulation of miR-137 and Spatial Learning and Memory Deficits

ATRX gene mutations have been identified in syndromic and non-syndromic intellectual disabilities in humans. ATRX is known to maintain genomic stability in neuroprogenitor cells, but its function in differentiated neurons and memory processes remains largely unresolved. Here, we show that the deletion of neuronal Atrx in mice leads to distinct hippocampal structural defects, fewer presynaptic vesicles, and an enlarged postsynaptic area at CA1 apical dendrite-axon junctions. We identify male-specific impairments in long-term contextual memory and in synaptic gene expression, linked to altered miR-137 levels. We show that ATRX directly binds to the miR-137 locus and that the enrichment of the suppressive histone mark H3K27me3 is significantly reduced upon the loss of ATRX. We conclude that the ablation of ATRX in excitatory forebrain neurons leads to sexually dimorphic effects on miR-137 expression and on spatial memory, identifying a potential therapeutic target for neurological defects caused by ATRX dysfunction.

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Loss of ATRX in neurons has sexually dimorphic effects on long-term spatial memory

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Targeted deletion of neuronal ATRX in mice causes ultrastructural synaptic defects

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ATRX null neurons show sex-specific changes in miR-137 and target synaptic transcripts

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ATRX directly binds and suppresses miR-137 in males via enrichment of H3K27me3

Upregulation of miR-137 Expression Suppresses Tumor Growth and Progression via Interacting with DNMT3a Through Inhibiting the PTEN/Akt Signaling in HCC

Background

Downregulation of miR-137 regulates tumor growth in hepatocellular carcinoma (HCC). Yet, the underlying molecular mechanisms stay unclear.

Materials and Methods

miR-137 and DNA methyltransferase 3a (DNMT3a) expression levels were detected by Western blot, immunohistochemistry and qRT-PCR assays. Luciferase reporter and Western blot assays were also carried out to explore the correlation of miR-137 and DNMT3a. Flow cytometry assay, MTT analysis, transwell and wound healing assay were used to evaluate cell apoptosis, proliferation, as well as invasive and migratory abilities. Western blot was used to examine the caspase-3, cleaved caspase-3, PCNA, MMP-2, and MMP-7 protein levels, as well as PTEN/Akt signaling alternations. Methylation-specific PCR was applied to detect the PTEN promoter methylation status. Xenograft tumor assay, Western blot and immunohistochemistry analyses were taken to confirm the miR-137 regulation in vivo.

Results

Downregulation of miR-137, upregulation of DNMT3a, as well as an inverse correlation between them were observed in HCC clinical samples and cells. Moreover, miR-137 targeted directly and inhibited DNMT3a in HCC cells, which further retarded cell proliferative, migratory and invasive capabilities, while promoted apoptotic ones. Additionally, miR-137 overexpression inactivated the PTEN/Akt pathway in HCC cell by decreasing DNMT3a expression. Furthermore, miR-137 overexpression inhibited tumor growth in vivo in HCC via interacting with DNMT3a through inhibiting the PTEN/Akt cascades.

Conclusion

Our findings suggested that miR-137 inhibited HCC tumor growth and progression via interacting with DNMT3a and suppressing the PTEN/Akt signaling in vitro and in vivo.

The methylation landscape and its role in domestication and gene regulation in the chicken

Domestication is one of the strongest examples of artificial selection and has produced some of the most extreme within-species phenotypic variation known. In the case of the chicken, it has been hypothesized that DNA methylation may play a mechanistic role in the domestication response. By inter-crossing wild-derived red junglefowl with domestic chickens, we mapped quantitative trait loci for hypothalamic methylation (methQTL), gene expression (eQTL) and behaviour. We find large, stable methylation differences, with 6,179 cis and 2,973 trans methQTL identified. Over 46% of the trans effects were genotypically controlled by five loci, mainly associated with increased methylation in the junglefowl genotype. In a third of eQTL, we find that there is a correlation between gene expression and methylation, while statistical causality analysis reveals multiple instances where methylation is driving gene expression, as well as the reverse. We also show that methylation is correlated with some aspects of behavioural variation in the inter-cross. In conclusion, our data suggest a role for methylation in the regulation of gene expression underlying the domesticated phenotype of the chicken.

MicroRNA‑137 regulates hypoxia‑mediated migration and epithelial‑mesenchymal transition in prostate cancer by targeting LGR4 via the EGFR/ERK signaling pathway

MicroRNAs (miRs) serve an integral role in prostate cancer. The present study aimed to investigate the effects and mechanisms of miR‑137 in hypoxia‑mediated migration and epithelial‑mesenchymal transition (EMT). PC3 and DU145 prostate cancer cells were exposed to hypoxia for 24 h, after which the expression of miR‑137 was determined by reverse transcription‑quantitative PCR (RT‑qPCR). The cells were transfected with a miR‑137 mimic or inhibitor, followed by hypoxia exposure. The results demonstrated that hypoxia reduced miR‑137 expression. Further results from the Cell Counting Kit‑8, Cell Death Detection ELISA plus kit, Transwell assay, RT‑qPCR and western blotting assays revealed that the miR‑137 mimic prevented cell proliferation, facilitated apoptosis and repressed cell migration, invasiveness, and expression of N‑cadherin, vimentin and matrix metalloproteinase 2; the miR‑137 inhibitor exerted the opposite effects. A dual‑-luciferase reporter assay determined that miR‑137 directly targeted leucine‑rich repeat‑containing G protein‑coupled receptor 4 (LGR4). Additionally, miR‑137 negatively regulated the epidermal growth factor receptor/extracellular signal‑-regulated kinase (EGFR/ERK) signaling pathway by targeting LGR4. LGR4 silencing or EGFR/ERK inhibition abolished the effects of miR‑137 inhibitor on cell migration and EMT. In conclusion, by targeting LGR4 via the EGFR/ERK signaling pathway, miR‑137 inhibited prostate cancer cell migration and EMT.

MicroRNA-137 Inhibits Cancer Progression by Targeting Del-1 in Triple-Negative Breast Cancer Cells

MicroRNAs (miRNAs) can be used to target a variety of human malignancy by targeting their oncogenes or tumor suppressor genes. The developmental endothelial locus-1 (Del-1) might be under miRNA regulation. This study investigated microRNA-137 (miR-137) function and Del-1 expression in triple-negative breast cancer (TNBC) cells and tissues. Del-1 mRNA and miRNA-137 levels were determined via qRT-PCR in breast cancer cells (MDA-MB-231, MCF7, SK-BR3, and T-47D) and tissues from 30 patients with TNBC. The effects of miR-137 on cell proliferation, migration, and invasion were determined using MTT assays, wound healing, and Matrigel transwell assays. The luciferase reporter assay revealed direct binding of miR-137 to the 3'-UTR of Del-1. miR-137 inhibited cell proliferation, migration, and invasion of MDA-MB-231 cells. Among the 30 TNBC specimens, miR-137 was downregulated and Del-1 level in plasma was significantly elevated relative to normal controls. It is concluded that miR-137 regulates Del-1 expression in TNBC by directly binding to the Del-1 gene and cancer progression. The results implicate miR-137 as a new therapeutic biomarker for patients with TNBC.

miR-137 alleviates doxorubicin resistance in breast cancer through inhibition of epithelial-mesenchymal transition by targeting DUSP4

Acquired resistance to chemotherapy is a major obstacle in breast cancer (BC) treatment. Accumulated evidence has uncovered that microRNAs (miRNAs) are vital regulators of chemoresistance in cancer. Growing studies reveal that miR-137 acts as a suppressor in tumor progression. However, it remains obscure the role of miR-137 in modulating the sensitivity of BC cells to doxorubicin (DOX). In this study, we demonstrate that miR-137 exerts a significant effect on repressing the development of chemoresistance of BC cells in response to DOX via attenuating epithelial-mesenchymal transition (EMT) of tumor cells in vitro and in vivo. MiR-137 overexpression dramatically elevated the sensitivity of BC cells to DOX as well as impaired the DOX-promoted EMT of tumor cells. Mechanistically, miR-137 directly targeted dual-specificity phosphatase 4 (DUSP4) to impact on the EMT and chemoresistance of BC cells upon DOX treatment. Consistently, decreased DUSP4 efficiently enhanced the sensitivity of BC cells to DOX while overexpressed DUSP4 significantly diminished the beneficial effect of miR-137 on BC cells chemoresistance. Moreover, the increased miR-137 heightened the sensitivity of BC cells-derived tumors to DOX through targeting DUSP4 in vivo. Together, our results provide a novel insight into the DOX resistance of BC cells and miR-137 may serve as a new promising therapeutic target for overcoming chemoresistance in BC.

Genome-wide analysis to identify a novel microRNA signature that predicts survival in patients with stomach adenocarcinoma

Objective: Using genome-wide screening, this study was aimed at identifying prognostic microRNA (miRNA) in those patients suffering from stomach adenocarcinoma (STAD).

Methods: A genome-wide miRNA sequencing dataset and relevant STAD clinical information was obtained via The Cancer Genome Atlas (TCGA). Prognostic miRNA selection was carried out through a whole genome multivariate Cox regression model in order to establish a prognostic STAD signature.

Results: Eleven miRNAs (hsa-mir-509-2, hsa-mir-3917, hsa-mir-495, hsa-mir-653, hsa-mir-3605, hsa-mir-2115, hsa-mir-1292, hsa-mir-137, hsa-mir-6511b-1, hsa-mir-145, and hsa-mir-138-2) were recognized as prognostic and used for the construction of a STAD prognostic signature. This signature exhibited good performance in predicting prognosis (adjusted P<0.0001, adjusted hazard ratio= 3.047, and 95% confidence interval=2.148-4.323). The time-dependent receiver operating characteristic examination exhibited area under curve values of 0.711, 0.697, 0.716, 0.733, 0.805, and 0.805, for 1-, 2-, 3-, 4-, 5-, and 10-year overall survival (OS) estimation, respectively. Comprehensive survival analysis suggests that the 11-miRNA prognostic signature acts as an independent feature of STAD prognosis and exhibits superior performance in OS prediction when compared to traditional clinical parameters. Furthermore, fourteen miRNA target genes were linked to STAD OS. These included SERPINE1, MLEC, ANGPT2, C5orf38, FZD7, MARCKS, PDGFD, DUSP6, IRS1, PSAT1, TENM3, TMEM127, BLMH, and TIRAP. Functional and gene set enrichment analysis suggested that target genes and the 11-miRNA prognostic signature were both participate in various biological processes and pathways, including the growth factor beta, Wnt, and Notch signaling pathways.

Conclusions: By means of a genome-wide analysis, an 11-miRNA expression signature that may serve as an underlying prognostic indicator for those patients suffering from STAD has been identified and described here.

KLF12 Regulates Mouse NK Cell Proliferation

NK cells are innate lymphocytes that play an integral role in tumor rejection and viral clearance. Unlike their other lymphocyte counterparts, NK cells have the unique ability to recognize and lyse target cells without prior exposure. However, there are no known NK cell-specific genes that are exclusively expressed by all NK cells. Therefore, identification of NK cell-specific genes would allow a better understanding of why NK cells are unique cytotoxic lymphocytes. From the Immunological Genome (ImmGen) Consortium studies, we identified kruppel-like factor 12 (Klf12), encoding a novel transcription factor, preferentially expressed in C57BL/6 mouse NK cells. KLF12 was dispensable for NK cell development, IFN-γ production, degranulation, and proliferation in Klf12 knockout mice. RNA-sequencing analysis revealed increased expression of Btg3, an antiproliferative gene, in KLF12-deficient NK cells compared with wild-type NK cells. Interestingly, competitive mixed bone marrow chimeric mice exhibited reduced development of KLF12-deficient NK cells, altered IFN-γ production and degranulation, and impairment of NK cell proliferation in vitro and in vivo in response to mouse CMV infection. KLF12-deficient NK cells from bone marrow chimeric mice also expressed higher levels of the IL-21R, which resulted in increased IL-21R signaling and correlated with greater inhibition of NK cell proliferation. Furthermore, IL-21 induced Btg3 expression, which correlated with arrested NK cell maturation and proliferation. In summary, we found that KLF12 regulates mouse NK cell proliferation potentially by regulating expression of Btg3 via IL-21.

Analysis of microRNA expression profiles reveals a 5‑microRNA prognostic signature for predicting overall survival time in patients with gastric adenocarcinoma

There is growing evidence supporting dysregulated microRNAs (miRNAs) as potential prognostic biomarkers in cancer. The present study aimed to identify an miRNA model set with prognostic power for patients with gastric adenocarcinoma. miRNA‑seq data from 155 patients and 37 controls were downloaded from The Cancer Genome Atlas (TCGA) database for a comprehensive analysis of miRNA expression profiles and were used as training data. A total of 5 prognostic miRNAs, which have not been previously reported, were identified using univariate and multivariate Cox regression analyses. A separate 155‑patient TCGA cohort was used as a validation set for evaluation of the risk model. Patients in the training set were assigned into high‑ and low‑risk groups according to the 5‑miRNA signature risk scores. Kaplan‑Meier survival analyses demonstrated that patients with high risk scores had significantly shorter survival times than those with low risk scores. The risk model validation confirmed the prognostic ability of this 5‑miRNA signature in predicting the risk status of patients. Stratification analysis for clinical prognostic variables demonstrated recurrence and age were significant prognostic factors in the low‑ and high‑risk groups, respectively. In conclusion, the present 5‑miRNA signature is a potential independent risk factor for patient outcomes. The risk model based on the 5‑miRNA signature performed well in predicting overall survival time in patients with gastric adenocarcinoma.

Mechanism of miR-137 regulating migration and invasion of melanoma cells by targeting PIK3R3 gene

OBJECTIVE

To investigate the effect of microRNA-137 (miR-137) on the migration and invasion of melanoma cells and its mechanism.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of miR-137 in melanoma tissues and cells. miR-137 mimics, phosphoinositide-3-kinase regulatory subunit 3 (PIK3R3) small interfering RNA and corresponding controls were transfected into A375 and WM451 cells by lipofection. The expression of PIK3R3 was examined by qRT-PCR and Western blot analysis. The Trans-well assay was conducted to measure cell migration and invasion. Dual luciferase reporter assay was used to detect the interaction between miR-137 and PIK3R3.

RESULTS

Compared with normal pigmented nevus tissue, miR-137 expression was significantly reduced in melanoma tissues. Compared with keratinous HaCaT cells, the level of miR-137 was significantly decreased in melanoma SK-MEL-1, A375, and WM451 cells. Knockdown of miR-137 significantly reduced the migrated and invasive abilities of melanoma A375 and WM451 cells. Moreover, inhibition of PIK3R3 obviously suppressed the migration and invasion abilities of melanoma A375 and WM451 cells. Luciferase activity assay showed that PIK3R3 was a direct target of miR-137. In addition, overexpression of miR-137-inhibited PIK3R3 expression, while knockdown of miR-137-enhanced PIK3R3 abundance. Restoration of PIK3R3 reversed the regulatory effect of miR-137 on cell migration and invasive in melanoma A375 and WM451 cells.

CONCLUSION

miR-137 inhibited melanoma cell migration and invasion by targeting PIK3R3 gene.

MicroRNA-137 reduces stemness features of pancreatic cancer cells by targeting KLF12

Background

Cancer stem cells (CSCs) play an important role in the development of pancreatic cancer. We previously showed that the microRNA miR-137 is downregulated in clinical samples of pancreatic cancer, and its expression negatively regulates the proliferation and invasiveness of pancreatic cancer cells.

Methods

The stemness features of pancreatic cancer cells was detected by flow cytometry, immunofluorescence and sphere formation assay. Xenograft mouse models were used to assess the role of miR-137 in stemness features of pancreatic cancer cells in vivo. Dual-luciferase reporter assays were used to determine how miR-137 regulates KLF12. Bioinformatics and Chromatin immunoprecipitation analysis of KLF12 recruitment to the DVL2 promoters. Involvement of the Wnt/β-catenin pathways was investigated by western blot and Immunohistochemistry.

Results

miR-137 inhibits pancreatic cancer cell stemness in vitro and vivo. KLF12 as miR-137 target inhibits CSC phenotype in pancreatic cancer cells. Suppression of KLF12 by miR-137 inhibits Wnt/β-catenin signalling. KLF12 expression correlates with DVL2 and canonical Wnt pathway in clinical pancreatic cancer.

Conclusion

Our results suggest that miR-137 reduces stemness features of pancreatic cancer cells by Targeting KLF12-associated Wnt/β-catenin pathways and may identify new diagnostic and therapeutic targets in pancreatic cancer.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1105-3) contains supplementary material, which is available to authorized users.

DANCR contributed to hepatocellular carcinoma malignancy via sponging miR-216a-5p and modulating KLF12

Long noncoding RNA (lncRNA) differentiation antagonizing nonprotein coding RNA (DANCR) has been identified as an oncogene in several cancers. However, the biological function and role of DANCR in hepatocellular carcinoma (HCC) remain unclear. Our current study aimed to investigate the detailed mechanism of DANCR in HCC. We found that DANCR was significantly upregulated in HCC cell lines in comparison to LO2 cells. Then, we observed that knockdown of DANCR could greatly inhibit Huh7 and HepG2 cell proliferation. In addition, HCC cell apoptosis was increased by silence of DANCR and meanwhile, cell cycle progression was blocked in G1 phase. Apart from these, downregulation of DANCR repressed HCC cell migration and invasion ability obviously. As predicted by the bioinformatics analysis, microRNA-216a-5p (miR-216a-5p) could serve as a direct target of DANCR. MiR-216a-5p has been reported to be involved in many cancers. Here, the correlation between miR-216a-5p and DANCR was confirmed using dual-luciferase reporter assay and radioimmunoprecipitation assay. Subsequently, Kruppel-like factor 12 (KLF12) exerts an important role in different tumor types. KLF12 can function as a downstream target of miR-216a-5p. Finally, the in vivo experiments were used and the data proved that DANCR also strongly suppressed HCC tumor growth in vivo via targeting miR-216a-5p and KLF12. In conclusion, our study indicated that DANCR might provide a new perspective for HCC treatment.

Dysregulation of Krüppel-like factor 12 in the development of endometrial cancer

OBJECTIVE

Endometrial cancer (EC) remains a malignancy with poor survival outcome. To investigate the role of Krüppel-like factor 12 (KLF12), a transcription factor, in the progression of human EC.

METHODS

Immunohistochemistry, real time-PCR and western blot analysis of KLF12 expression in EC patients' tissues. Bioinformatics analysis revealed the clinical importance of KLF12 expression and survival ratio. Overexpression of KLF12 was generated using the ViraPower Adenoviral Expression System in EC cell lines. Cell viability assay, cell apoptosis assay and cell migration assay were used to determine cell proliferation, cell apoptosis and cell migration, respectively. Western blot analysis was carried out to determine the protein levels in cell lines and animal tissues.

RESULTS

The expression of KLF12 was observed to be much higher in human EC tissues compared with normal endometrium. Moreover, KLF12 expression was correlated positively with disease recurrence and was also associated with decreased survival probability. The overexpression of KLF12 in EC cell lines resulted in increased cell proliferation, decreased cell apoptosis and enhanced cell migration. Furthermore, overexpression of KLF12 also increased tumor size in vivo. Moreover, up-regulation of KLF12 dramatically increased the expression levels of MMP2, MMP9, pAKT S473 and CCND1. Our research reveals that overexpressed KLF12 contributes the growth of EC tumor by activating AKT signaling and increasing CCND1expression level.

CONCLUSIONS

To our knowledge, this is the first study to explore the significance of KLF12 in the development of EC, and KLF12 is expected to provide a novel potential therapeutic target for EC treatment.

The down-regulation of microRNA-137 contributes to the up-regulation of retinoblastoma cell proliferation and invasion by regulating COX-2/PGE2 signaling

MicroRNA-137 (miR-137) plays an important role in the development and progression of many types of human cancers; however, the role of miR-137 in retinoblastoma (RB) remains unclear. In this study, we aimed to investigate the functional significance and molecular mechanisms of miR-137 in RB. We reported that miR-137 was frequently down-regulated in RB tissues and cell lines. The overexpression of miR-137 inhibited RB cell proliferation and invasion, while the suppression of miR-137 promoted RB cell proliferation and invasion. Bioinformatic analysis predicted that cyclooxygenase-2 (COX-2) was a potential target gene of miR-137, which was validated by a dual-luciferase reporter assay. Moreover, our results showed that miR-137 negatively regulated the expression of COX-2 and the production of prostaglandin E2 (PGE2) in RB cells. The knockdown of COX-2 suppressed the proliferation and invasion of RB cells as well as the production of PGE2. The overexpression of COX-2 significantly reversed the inhibitory effect of miR-137 overexpression on RB cell proliferation and invasion. Taken together, these results suggest that miR-137 suppresses the proliferation and invasion of RB cells by targeting COX-2/PGE2. Our study reveals a tumor suppressive role of miR-137 in the progression of RB and suggests miR-137 as a potentially effective therapeutic target for the treatment of RB.

MiR-129-5p functions as a tumor suppressor in gastric cancer progression through targeting ADAM9

MicroRNAs (miRNAs) are identified as key regulators in cancer initiation, progression and metastasis including gastric cancer (GC). The aim of the study is to explore clinical significance and potential mechanism of miR-129-5p in GC development. In the study, our results found that miR-129-5p expression was significantly downregulated in GC tissues, compared with adjacent normal tissues using qRT-PCR analyses. Furthermore, lower miR-129-5p expression closely associated with tumor size and lymph node invasion and poor prognosis of GC patients. Using CCK8 assay, cell colony formation, transwell invasion assay, we demonstrated that miR-129-5p overexpression reduced cell proliferation, cell colony formation and cell invasion capacity in MKN45 (higher miR-129-5p expression) and SGC-7901 (lower miR-129-5p expression). However, downregulation of miR-129-5p had reverse effects on cell proliferation and invasion. Targeting association analysis, dual luciferase assay, qRT-PCR and western blot analysis results verified that miR-129-5p could target the 3'UTR of ADAM9 mRNA and regulated its protein expression. Furthermore, we confirmed that miR-129-5p suppressed cell proliferation and invasion ability through regulating ADAM9. In vivo, upregulation of miR-129-5p also inhibited tumor growth. Therefore, these results indicated that miR-129-5p functioned as a tumor suppressor in GC and may be a potential target of GC treatment.

Expression of miR-634 in gastric carcinoma and its effects on proliferation, migration, and invasion of gastric cancer cells

This study aims to observe the expression of microRNA (miR)‐634 in different gastric cancer cell lines and tissues, and to study the effects of miR‐634 on the proliferation, migration, and invasion of the gastric cancer cells. The miR‐634 mimics and miR‐634 inhibitors were transfected by lentivirus into human gastric cancer SGC‐7901 and MGC‐803 cells, and the miR‐634 cells without transfection were used as the control group (NC group). The expression of miR‐634 in the transfected cells was detected by qRT‐PCR. Cell viability was measured by the CCK8 assay. The migration and invasion ability of the cells were detected by scratch assays and Transwell^® chamber assays, respectively, and the luciferase assay verified the binding of miR‐634 to the target gene JAG1. The expression level of miR‐634 in gastric cancer tissues and cell lines was significantly lower than that in normal adjacent tissues and control cells. The survival of cells was significantly decreased, and number of cells migrating and invading was decreased in the miR‐634 mimics group. However, in the miR‐634 inhibitor group, the opposite results were observed. Over‐expression of miR‐634 inhibited the proliferation, migration, and invasion of gastric cancer cell lines, and the miR‐634 target gene was JAG1.

Long non-coding RNA LOC100129148 functions as an oncogene in human nasopharyngeal carcinoma by targeting miR-539-5p

Emerging studies have shown that long noncoding RNAs (lncRNAs) play critical roles in carcinogenesis and progression, including human nasopharyngeal carcinoma (NPC). The correlation between lncRNAs expression and NPC development has not been well identified in the recent literature. Recently, high-through put analysis reveals that LOC100129148 is highly expressed in NPC. However, whether the aberrant expression of LOC100129148 in NPC is corrected with tumorigenesis or prognosis has not been investigated. Herein, we identified that LOC100129148 was up-regulated in NPC tissues and cell lines, and higher expression of LOC100129148 resulted in a markedly poorer survival time. Over-expressed LOC100129148 favored, but silenced LOC100129148 hampered cell proliferation in NPC cells. Additionally, LOC100129148 enhanced the KLF12 expression through functioning as a competitive 'sponge' for miR-539-5p. Thus, our study reports a novel mechanism underlying NPC carcinogenesis, and provides a potential novel diagnosis and treatment biomarker for NPC.

MiR-137 inhibited cell proliferation and migration of vascular smooth muscle cells via targeting IGFBP-5 and modulating the mTOR/STAT3 signaling

Abnormal proliferation of vascular smooth muscle cells (VSMCs) contributes to the development of cardiovascular diseases. Studies have shown the great impact of microRNAs (miRNAs) on the cell proliferation of VSMCs. This study examined the effects of miR-137 on the cell proliferation and migration of VSMCs and also explored the underlying molecular mechanisms. The mRNA and protein expression levels were determined by qRT-PCR and western blot assays, respectively. The CCK-8 assay, wound healing assay and transwell migration assay were performed to measure cell proliferation and migration of VSMCs. The miR-137-targeted 3’untranslated region of insulin-like growth factor-binding protein-5 (IGFBP-5) was confirmed by luciferase reporter assay. Platelet-derived growth factor-bb (PDGF-bb) treatment enhanced cell proliferation and suppressed the expression of miR-137 in VSMCs. The gain-of-function and loss-of-function assays showed that overexpression of miR-137 suppressed the cell proliferation and migration, and also inhibited the expression of matrix genes of VSMCs; down-regulation of miR-137 had the opposite effects on VSMCs. Bioinformatics analysis and luciferase report assay results showed that IGFBP-5 was a direct target of miR-137, and miR-137 overexpression suppressed the IGFBP-5 expression and down-regulation of miR-137 increased the IGFBP-5 expression in VSMCs. PDGF-bb treatment also increased the IGFBP-5 mRNA expression. In addition, enforced expression of IGFBP-5 reversed the inhibitory effects of miR-137 on cell proliferation and migration of VSMCs. More importantly, overexpression of miR-137 also suppressed the activity of mTOR/STAT3 signaling in VSMCs. Taken together, the results suggest that miR-137 may suppress cell proliferation and migration of VSMCs via targeting IGFBP-5 and modulating mTOR/STAT3 signaling pathway.

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

BACKGROUND

Previous articles have reported that expression levels of microRNAs (miRNAs) are associated with survival time of patients with gastric cancer (GC). A systematic review and meta-analysis was performed to study the outcome of it.

DESIGN

Meta-analysis.

METHODS

English studies estimating expression levels of miRNAs with any of survival curves in GC were identified up till March 19, 2017 through performing online searches in PubMed, EMBASE, Web of Science and Cochrane Database of Systematic Reviews by two authors independently. The pooled hazard ratios (HR) with 95% confidence intervals (CI) were used to estimate the correlation between miRNA expression and overall survival (OS).

RESULTS

Sixty-nine relevant articles about 26 miRNAs with 6148 patients were ultimately included. GC patients with high expression of miR-20b (HR=2.38, 95%CI=1.16-4.87), 21 (HR=1.77, 95%CI=1.01-3.08), 106b (HR=1.84, 95%CI=1.15-2.94), 196a (HR=2.66, 95%CI=1.94-3.63), 196b (HR=1.67, 95%CI=1.38-2.02), 214 (HR=1.84, 95%CI=1.27-2.67) or low expression of miR-125a (HR=2.06, 95%CI=1.26-3.37), 137 (HR=3.21, 95%CI=1.68-6.13), 141 (HR=2.47, 95%CI=1.34-4.56), 145 (HR=1.62, 95%CI=1.07-2.46), 146a (HR=2.60, 95%CI=1.63-4.13), 206 (HR=2.85, 95%CI=1.73-4.70), 218 (HR=2.61, 95%CI=1.74-3.92), 451 (HR=1.73, 95%CI=1.19-2.52), 486-5p (HR=2.45, 95%CI=1.65-3.65), 506 (HR=2.07, 95%CI=1.33-3.23) have significantly poor OS (P<0.05).

CONCLUSIONS

In summary, miR-20b, 21, 106b, 125a, 137, 141, 145, 146a, 196a, 196b, 206, 214, 218, 451, 486-5p and 506 demonstrate significantly prognostic value. Among them, miR-20b, 125a, 137, 141, 146a, 196a, 206, 218, 486-5p and 506 are strong biomarkers of prognosis in GC.