MicroRNA-197 inhibits cell proliferation by targeting GAB2 in glioblastoma

Comparison of Oncogenes, Tumor Suppressors, and MicroRNAs Between Schizophrenia and Glioma: The Balance of Power

The risk of cancer in schizophrenia has been controversial. Confounders of the issue are cigarette smoking in schizophrenia, and antiproliferative effects of antipsychotic medications. The author has previously suggested comparison of a specific cancer like glioma to schizophrenia might help determine a more accurate relationship between cancer and schizophrenia. To accomplish this goal, the author performed three comparisons of data; the first a comparison of conventional tumor suppressors and oncogenes between schizophrenia and cancer including glioma. This comparison determined schizophrenia has both tumor-suppressive and tumor-promoting characteristics. A second, larger comparison between brain-expressed microRNAs in schizophrenia with their expression in glioma was then performed. This identified a core carcinogenic group of miRNAs in schizophrenia offset by a larger group of tumor-suppressive miRNAs. This proposed "balance of power" between oncogenes and tumor suppressors could cause neuroinflammation. This was assessed by a third comparison between schizophrenia, glioma and inflammation in asbestos-related lung cancer and mesothelioma (ALRCM). This revealed that schizophrenia shares more oncogenic similarity to ALRCM than glioma.

Circ_0060055 Promotes the Growth, Invasion, and Radioresistance of Glioblastoma by Targeting MiR-197-3p/API5 Axis

Circular RNA (circRNA) has been shown to be involved in the regulation of human disease progression. Our study aims to reveal the role of circ_0060055 in the progression of glioblastoma (GBM) and its potential molecular mechanism. The expression of circ_0060055, microRNA (miR)-197-3p, and apoptosis inhibitor 5 (API5) was determined by quantitative real-time PCR. GBM cell proliferation, apoptosis, and invasion were assessed using cell counting kit 8 assay, colony formation assay, EdU assay, flow cytometry, and transwell assay. Besides, the radiosensitivity of cells also was assessed using colony formation assay. The interaction between miR-197-3p and circ_0060055 or API5 was analyzed by dual-luciferase reporter assay and RNA pull-down assay. Animal experiments were conducted to measure the effect of circ_0060055 on GBM tumor growth and radiosensitivity in vivo. Circ_0060055 was overexpressed in GBM tumor tissues and cells, and its silencing suppressed GBM cell proliferation and invasion, while promoted apoptosis and radiosensitivity. In terms of mechanism, circ_0060055 could interact with miR-197-3p, and miR-197-3p could target API5. API5 expression also could be positively regulated by circ_0060055. Function experiments suggested that miR-197-3p inhibitor abolished the effect of circ_0060055 knockdown on GBM cell growth, invasion, and radiosensitivity. MiR-197-3p repressed GBM cell progression and improved radiosensitivity, and this effect was eliminated by API5 upregulation. In vivo experiments confirmed that circ_0060055 knockdown reduced GBM tumor growth and enhanced the radiosensitivity of tumors. This study revealed that circ_0060055 contributed to GBM progression and radioresistance through miR-197-3p/API5 pathway, providing a potential target for GBM treatment.

Machine learning and bioinformatics approaches for classification and clinical detection of bevacizumab responsive glioblastoma subtypes based on miRNA expression

For the precise treatment of patients with glioblastoma multiforme (GBM), we classified and detected bevacizumab (BVZ)-responsive subtypes of GBM and found their differential expression (DE) of miRNAs and mRNAs, clinical characteristics, and related functional pathways. Based on miR-21 and miR-10b expression z-scores, approximately 30% of GBM patients were classified as having the GBM BVZ-responsive subtype. For this subtype, GBM patients had a significantly shorter survival time than other GBM patients (p = 0.014), and vascular endothelial growth factor A (VEGF) methylation was significantly lower than that in other GBM patients (p = 0.005). It also revealed 14 DE miRNAs and 7 DE mRNAs and revealed functional characteristics between GBM BVZ subgroups. After comparing several machine learning algorithms, the construction and cross-validation of the SVM classifier were performed. For clinical use, miR-197 was optimized and added to the miRNA panel for better classification. Afterwards, we validated the classifier with several GBM datasets and discovered some key related issues. According to this study, GBM BVZ subtypes can be classified and detected by a combination of SVM classifiers and miRNA panels in existing tissue GBM datasets. With certain modifications, the classifier may be used for the classification and detection of GBM BVZ subtypes for future clinical use.

Member Domain 3 (LRIG3) Activates Hypoxia-Inducible Factor-1 α/Vascular Endothelial Growth Factor (HIF-1α/VEGF) Pathway to Inhibit the Growth of Bone Marrow Mesenchymal Stem Cells in Glioma

Member domain 3 (LRIG3) of the LRIG gene family is down-regulated in several cancers. However, its role in bone marrow mesenchymal stem cells (BMSCs) in gliomas and the related mechanisms is unknown. The qRT-PCR assessed LRIG3 mRNA level. Rat BMSCs were randomly assigned into glioma group (BMSCs cultured in glioma microenvironment); LRIG3 overexpression group; and si-LRIG3 inhibitor group followed by analysis of LRIG3 expression, cell proliferation, PCNA and Ki-67 apoptosis, TNF-α; and HIF-1α/VEGF mRNA level. LRIG3 mRNA expression was decreased in gliomas patients (P < 0.05). BMSCs cultured in glioma microenvironment showed decreased LRIG3, increased cell proliferation, decreased PCNA, Ki-67 and TNF-α secretion as well as elevated HIF-1α and VEGF level (P < 0.05). Transfection of LRIG3 siRNA further promoted the above changes. Conversely, LRIG3 plasmid transfection significantly promoted its expression in glioma BMSCs (P < 0.05), inhibited cell proliferation, promoted PCNA, Ki-67, and TNF-α secretion, and increased HIF-1α and VEGF level (P < 0.05). LRIG3 in rat BMSCs cultured in the glioma microenvironment is decreased. Down-regulation of LRIG3 inhibits TNF-α secretion by activating HIF-1α/VEGF pathway regulating BMSCs proliferation and apoptosis.

miRNA signature in glioblastoma: Potential biomarkers and therapeutic targets

MicroRNAs (miRNAs) are transcripts with sizes of about 22 nucleotides, which are produced through a multistep process in the nucleus and cytoplasm. These transcripts modulate the expression of their target genes through binding with certain target regions, particularly 3' suntranslated regions. They are involved in the pathogenesis of several kinds of cancers, such as glioblastoma. Several miRNAs, including miR-10b, miR-21, miR-17-92-cluster, and miR-93, have been up-regulated in glioblastoma cell lines and clinical samples. On the other hand, expression of miR-7, miR-29b, miR-32, miR-34, miR-181 family members, and a number of other miRNAs have been decreased in this type of cancer. In the current review, we explain the role of miRNAs in the pathogenesis of glioblastoma through providing a summary of studies that reported dysregulation of these epigenetic effectors in this kind of brain cancer.

miR-197-3p reduces epithelial-mesenchymal transition by targeting ABCA7 in ovarian cancer cells

The present study was designed to explore the role of microRNA-197-3p in regulating the epithelial-mesenchymal cellular transition in ovarian cancer. The results showed that miR-197 to be significantly (P < 0.05) downregulated in human ovarian cancer tissues and cell lines. Overexpression of miR-197 significantly (P < 0.05) reduced the proliferation of OVACAR-3 cancer cells. Additionally, the colony formation of the OVACAR-3 cells was inhibited by 59% relative to control. The migration and invasion of the OVACAR-3 cells was inhibited by 64% and 72%, respectively, upon miR-197 overexpression. Western blot analysis showed miR-197 was found to upregulate the expression of E-cadherin, while the expression of N-cadherin, vimentin, and snail proteins was found to decrease significantly (P < 0.05). TargetScan analysis together with dual luciferase assay revealed that miR-197 exerts its effects by targeting ABCA7 in ovarian cancer. ABCA7 was significantly (P < 0.05) overexpressed in ovarian cancer tissues and cell lines. However, silencing of ABCA7 resulted in significant inhibition of cell proliferation, migration, and invasion. Nonetheless, overexpression of ABCA7 could abolish the tumor-suppressive effects of miR-197 on the OVACAR-3 cells. Taken together, miR-197 acts a tumor-suppressive in ovarian cancer and points towards its therapeutic implications in the treatment of ovarian cancer.

The Role of Circulating MicroRNA in Glioblastoma Liquid Biopsy

Glioblastoma multiforme (GBM) is the most common and aggressive primary malignancy of the central nervous system. The standard used to monitor disease progression and therapeutic response has been magnetic resonance imaging, which is usually obtained preoperatively and postoperatively. Patients with GBM are monitored every 2-3 months and scans are repeated until progression is detected. Sometimes there is an inability to detect tumor progression or difficulty in differentiating tumor progression from pseudoprogression. With the difficulty of distinguishing disease progression, as well as the cost of imaging, there may be a need for the existence of a noninvasive liquid biopsy. There is no reliable biomarker for GBM that can be used for liquid biopsy, but if one could be detected in serum or cerebrospinal fluid and vary with tumor burden, then, it could be developed into one. MicroRNAs (miRNAs) are short, single-stranded, noncoding RNAs that posttranscriptionally control gene expression. They play vital roles in tumor progression, migration, invasion, and stemness. Because miRNAs are secreted in stable forms in bodily fluid, either via extracellular vesicles or in cell-free form, they have great potential as biomarkers that can be used for liquid biopsy. Various miRNAs that are dysregulated in GBM have been identified in tissue, cerebrospinal fluid, and serum samples. There needs to be standardization of sample collection and quantification for both cell-free and exosomal-derived samples. Further studies need to be performed on larger cohorts to evaluate the sensitivity and specificity of not just miRNAs but most potential biomarkers.

MicroRNA Dysregulation in Pulmonary Arteries from Chronic Obstructive Pulmonary Disease. Relationships with Vascular Remodeling

Pulmonary vascular remodeling is an angiogenic-related process involving changes in smooth muscle cell (SMC) homeostasis, which is frequently observed in chronic obstructive pulmonary disease (COPD). MicroRNAs (miRNAs) are small, noncoding RNAs that regulate mRNA expression levels of many genes, leading to the manifestation of cell identity and specific cellular phenotypes. Here, we evaluate the miRNA expression profiles of pulmonary arteries (PAs) of patients with COPD and its relationship with the regulation of SMC phenotypic change. miRNA expression profiles from PAs of 12 patients with COPD, 9 smokers with normal lung function (SK), and 7 nonsmokers (NS) were analyzed using TaqMan Low-Density Arrays. In patients with COPD, expression levels of miR-98, miR-139-5p, miR-146b-5p, and miR-451 were upregulated, as compared with NS. In contrast, miR-197, miR-204, miR-485-3p, and miR-627 were downregulated. miRNA-197 expression correlated with both airflow obstruction and PA intimal enlargement. In an in vitro model of SMC differentiation, miR-197 expression was associated with an SMC contractile phenotype. miR-197 inhibition blocked the acquisition of contractile markers in SMCs and promoted a proliferative/migratory phenotype measured by both cell cycle analysis and wound-healing assay. Using luciferase assays, Western blot, and quantitative PCR, we confirmed that miR-197 targets the transcription factor E2F1. In PAs from patients with COPD, levels of E2F1 were increased as compared with NS. In PAs of patients with COPD, remodeling of the vessel wall is associated with downregulation of miR-197, which regulates SMC phenotype. The effect of miR-197 on PAs might be mediated, at least in part, by the key proproliferative factor, E2F1.

miR-486-5p inhibits cell proliferation and invasion through repressing GAB2 in non-small cell lung cancer

Previous studies have reported that cell metastasis is the main reason for the high mortality of non-small cell lung cancer (NSCLC). Many miRNAs have been identified to be involved in the development of NSCLC. In this study, we explored the effect of miR-486-5p and GAB2 on cell proliferation and invasion in NSCLC. First, miR-486-5p and GAB2 expression levels were detected in NSCLC through quantitative RT-qPCR, and downregulation of miR-486-5p and upregulation of GAB2 were both identified in NSCLC. Then MTT and Transwell analysis were performed to confirm the functions of miR-486-5p and GAB2 for cell proliferation and invasion in NSCLC. Moreover, miR-486-5p overexpression was found to inhibit proliferation and invasion by suppressing GAB2 in NSCLC cells. Besides, miR-486-5p overexpression lessened GAB2 expression level in NSCLC, while miR-486-5p knockout enhanced GAB2 expression level. Additionally, miR-486-5p was identified to directly target GAB2 through dual luciferase reporter assay. The silence of GAB2 was found to inhibit proliferation and invasion of NSCLC cells. Collectively, miR-486-5p contributed to inhibiting proliferation and invasion of NSCLC cells through regulating GAB2, and miR-486-5p/GAB2 axis may provide a breakthrough for diagnosing NSCLC.

Overexpression of miR-1283 Inhibits Cell Proliferation and Invasion of Glioma Cells by Targeting ATF4

It is well known that activating transcription factor 4 (ATF4) expression is closely associated with progression of many cancers. We found that miR-1283 could directly target ATF4. However, the precise mechanisms of miR-1283 in glioma have not been well clarified. Our study aimed to explore the interaction between ATF4 and miR-1283 in glioma. In this study, we found that the level of miR-1283 was dramatically decreased in glioma tissues and cell lines, the expression of ATF4 was significantly increased, and the low level of miR-1283 was closely associated with high expression of ATF4 in glioma tissues. Moreover, introduction of miR-1283 significantly inhibited proliferation and invasion of glioma cells. However, knockdown of miR-1283 promoted the proliferation and invasion in glioma cells. Bioinformatics analysis predicted that the ATF4 was a potential target gene of miR-1283. Luciferase reporter assay demonstrated that miR-1283 could directly target ATF4. In addition, knockdown of ATF4 had similar effects with miR-1283 overexpression on glioma cells. Upregulation of ATF4 in glioma cells partially reversed the inhibitory effects of miR-1283 mimic. Overexpression of miR-1283 inhibited cell proliferation and invasion of glioma cells by directly downregulating ATF4 expression.

miR-197 is downregulated in cervical carcinogenesis and suppresses cell proliferation and invasion through targeting forkhead box M1

Cervical cancer is the second most common type of cancer in females worldwide. It has been demonstrated that microRNAs (miRs) serve important roles in the occurrence and development of various types of cancer, including cervical cancer. The results of the present study revealed that miR-197 was downregulated in cervical cancer tissues and cell lines. Restoration of miR-197 expression significantly inhibited cell viability and invasion of cervical cancer. Additionally, forkhead box M1 (FOXM1) was identified as a direct target gene of miR-197. Bioinformatic analysis revealed that FOXM1 was a potential target gene of miR-197. Luciferase reporter assay, reverse transcription-quantitative polymerase chain reaction and western blot analysis demonstrated that miR-197 decreased FOXM1 expression through direct binding to its 3'-untranslated region. Furthermore, the effects of FOXM1 underexpression were comparable with the effects induced by miR-197 overexpression in cervical cancer cells, suggesting that FOXM1 acted as a downstream effector in miR-197-mediated proliferation and invasion of cervical cancer cells. The results of the present study suggested that miR-197 inhibited growth and metastasis of cervical cancer by directly targeting FOXM1.

MicroRNA-103 suppresses glioma cell proliferation and invasion by targeting the brain-derived neurotrophic factor

Glioma is the most common and aggressive of malignant brain tumours. MicroRNAs (miRNAs/miRs) are involved in tumour development of various human cancers, including glioma. Therefore, miRNAs may have potential tumour diagnostic, prognostic and therapeutic values in human glioma. miR‑103 is abnormally expressed in various human cancer types. However, the detailed expression pattern, biological functions and underlying molecular mechanism of miR‑103 in glioma remain unclear. Therefore, the present study aimed to investigate the expression, biological roles and underlying mechanisms of miR‑103 in glioma. Results of the present study demonstrated that miR‑103 was significantly down‑regulated in glioma tissues and cell lines. Functional experiments demonstrated that miR‑103 overexpression inhibited the proliferation and invasion of glioma cells in vitro. Additionally, brain‑derived neurotrophic factor (BDNF) was identified as a direct functional target of miR‑103 in glioma. Furthermore, mRNA and protein expression levels of BDNF were highly upregulated in glioma tissues compared with normal brain tissues. Spearman's correlation analysis indicated a negative association between miR‑103 and BDNF mRNA expression levels in glioma tissues. Furthermore, rescue experiments demonstrated that BDNF up‑regulation reversed the suppressive effects of miR‑103 on glioma cell proliferation and invasion. Therefore, the authors of the present study hypothesized that the interaction between miR‑103 and BDNF serves a role in glioma progression and, in the future, may serve as a therapeutic target for glioma treatment.

The Long Noncoding RNA HOTAIR Promotes Colorectal Cancer Progression by Sponging miR-197

The long noncoding RNA HOX transcript antisense RNA (HOTAIR) has been found to be overexpressed in many human malignancies and involved in tumor progression and metastasis. Although the downstream target through which HOTAIR modulates tumor metastasis is not well known, evidence suggests that microRNA-197 (miR-197) might be involved in this event. In the present study, the significance of HOTAIR and miR-197 in the progression of colorectal cancer was detected in vitro and in vivo. We found that HOTAIR expression was significantly increased in colorectal cancer cells and tissues. In contrast, the expression of miR-197 was obviously decreased. We further demonstrated that HOTAIR knockdown promoted apoptosis and inhibited cell proliferation, migration, and invasion in vitro and in vivo. Moreover, HOTAIR modulated the progression of colorectal cancer by competitively binding miR-197. Taken together, our study has identified a novel pathway through which HOTAIR exerts its oncogenic role and provided a molecular basis for potential applications of HOTAIR in the prognosis and treatment of colorectal cancer.

MicroRNA-197 inhibits gastric cancer progression by directly targeting metadherin

Gastric cancer is the fifth most frequent malignancy and the fourth most common cause of cancer‑associated mortality worldwide. MicroRNAs (miRNAs) are a group of small RNAs that regulate several cellular processes. In particular, a large number of miRNAs are involved in gastric cancer formation and progression. Thus, miRNAs may be considered as effective diagnostic biomarkers and therapeutic methods for gastric cancer. The aim of the current study was to detect miRNA (miR)‑197 expression in gastric cancer and to investigate its biological role and associated mechanism in gastric cancer. In the present study, miR‑197 expression was demonstrated to be considerably downregulated in gastric cancer tissues and cell lines. Its low expression level was associated with tumour size, invasive depth, tumour‑node‑metastasis staging and lymph node metastasis. High expression of miR‑197 inhibited tumour cell proliferation and invasion in vitro. Subsequently, metadherin (MTDH) was identified as a direct target gene of miR‑197 in gastric cancer, and this was confirmed by bioinformatics analysis, Dual‑luciferase reporter assay, reverse transcription quantitative polymerase chain reaction and western blot analysis. MTDH expression was upregulated in gastric cancer and was inversely correlated with miR‑197 expression levels. In addition, MTDH overexpression prevented the proliferation and inhibited invasion induced by miR‑197 overexpression. In addition, miR‑197 was demonstrated to regulate the phosphatase and tensin homolog (PTEN)/AKT signalling pathway in gastric cancer. The results of the present study suggested that miR‑197 serves a tumour‑suppressing role in human gastric carcinogenesis and progression by regulating the MTDH/PTEN/AKT signalling pathway. The miR‑197/MTDH axis may provide a novel effective therapeutic target for patients with gastric cancer.

Gab2 mediates hepatocellular carcinogenesis by integrating multiple signaling pathways

Our previous studies have found that Growth factor receptor-bound protein 2-associated binding protein 2 (Gab2)-a docking protein-governs the development of fatty liver disease. Here, we further demonstrate that Gab2 mediates hepatocarcinogenesis. Compared with a faint expression in para-carcinoma tissue, Gab2 was highly expressed in ∼60-70% of human hepatocellular carcinoma (HCC) specimens. Deletion of Gab2 dramatically suppressed diethylnitrosamine-induced HCC in mice. The oncogenic effects of Gab2 in HepG2 cells were promoted by Gab2 overexpression but were rescued by Gab2 knockdown. Furthermore, Gab2 knockout in HepG2 cells restrained cell proliferation, migration and tumor growth in nude mice. Signaling pathway analysis with protein kinase inhibitors demonstrated that oncogenic regulation by Gab2 in hepatic cells involved multiple signaling molecules, including ERK, Akt, and Janus kinases (Jaks), especially those that mediate inflammatory signaling. IL-6 signaling was increased by Gab2 overexpression and impaired by Gab2 deletion via regulation of Jak2 and signal transducer and activator of transcription 3 phosphorylation and the expression of downstream genes, such as Bcl-2 (B-cell lymphoma 2), c-Myc, MMP7 (matrix metalloproteinase-7), and cyclin D1in vitro and in vivo These data indicate that Gab2 mediates the pathologic progression of HCC by integrating multiple signaling pathways and suggest that Gab2 might be a powerful therapeutic target for HCC.-Cheng, J., Zhong, Y., Chen, S., Sun, Y., Huang, L., Kang, Y., Chen, B., Chen, G., Wang, F., Tian, Y., Liu, W., Feng, G.-S., Lu, Z. Gab2 mediates hepatocellular carcinogenesis by integrating multiple signaling pathways.