MicroRNA-9 inhibits the gastric cancer cell proliferation by targeting TNFAIP8

The role of microRNA-9 in ovarian and cervical cancers: An updated overview

Ovarian and cervical cancers are the two most frequent kind of gynaecological cancers (GCs). In spite of advances in prevention, screening and treatment, cervical cancer still leads to an increased morbidity and mortality worldwide. Ovarian cancer is often detected at a late stage, which significantly reduces the effectiveness of available treatments. Therefore, novel methods are desperately needed to improve the clinical care of GC patients. MicroRNAs, also known as short noncoding RNAs (miRNAs/miRs), are a diverse group of RNAs with a length of 22 nucleotides. These typically cause translational repression and mRNA degradation by interacting with target mRNAs' 3' untranslated region (3'-UTR), together with other regions and gene promoters. Under certain conditions, they are also able to activate translation or regulate transcription. It has been demonstrated that miRNAs are crucial to several biological processes leading to tumorigenesis, including GCs. Recent research has shown that miR-9 affects carcinogenesis. In this review, we will provide an overview of current research on the potential utility of miR-9 in the diagnosis, prognosis, and therapy of ovarian and cervical malignancies.

Synovial fluid exosome-derived miR-182-5p alleviates osteoarthritis by downregulating TNFAIP8 and promoting autophagy through LC3 signaling

OBJECTIVE

To investigate the role of exosomal miRNAs from synovial fluid (SF) in osteoarthritis (OA) patients and investigate the underlying molecular mechanism.

METHODS

Degenerated knee tissues were collected from male and female OA patients. Enzyme-linked immunosorbent assay (ELISA) was used to detect the differences in the expression of inflammatory indicators, including TNF-α, IL-6, and IL-10, between the degenerative and injury groups. Exosomes were isolated from SF using the Exoquick kit, and a microarray was used to identify differentially expressed miRNAs (DEmiRNAs), which were analyzed using bioinformatics. The predicted relationship between DEmiRNAs and target genes was verified using a luciferase reporter gene assay. CCK-8 and transwell assays were used to assess cell viability and migration. Immunofluorescence and TUNEL assay were used to detect cell autophagy and apoptosis. The interaction between proteins was detected by immunoprecipitation and verified by Mab rescue assay.

RESULTS

The relative expression of TNF-α/IL6 was significantly higher in the degeneration group than in the injury group. The OA degeneration group released significantly more and smaller exosomes than the injury group. The expression of miR-182-5p was markedly reduced in OA patients and had a higher correlation with inflammatory indicators. Tumor necrosis factor α-induced protein 8 (TNFAIP8) was a target of miR-182-5p, and its overexpression promoted chondrocyte proliferation, migration, and invasion and enhanced the wound healing efficiency. We also found a direct interaction of TNFAIP8 with autophagy-related gene 3 (ATG3). TNFAIP8 triggered ATG3 LC3-mediated autophagy.

CONCLUSION

The downregulation of exosomal miR-182-5p inhibits OA degeneration by targeting TNFAIP8 via the ATG/LC3 pathway.

Tumor cells-derived exosomal circVCP promoted the progression of colorectal cancer by regulating macrophage M1/M2 polarization

BACKGROUND

Colorectal cancer (CRC) is among the most frequent tumors of the digestive tract and the second leading cause of cancer death worldwide. Tumor-associated macrophages (TAMs) are one of the most critical immune cells in the tumor microenvironment, which closely interact with tumor cells to promote tumor incidence and progression. However, the precise mechanism of action between CRC cells and TAMs polarization is still being investigated.

METHODS

Transmission electronic microscopy (TEM), NanoSight and western blotting were used to characterize exosomes (Exo) isolated from the culture medium of CRC cells. The cellular uptake and internalization of Exo were detected by confocal laser scanning microscopy. M1/ M2 phenotype markers expression were examined by ELISA and flow cytometry. Cell migration, invasion and proliferation were determined by transwell and CCK-8 assay, respectively. A xenograft tumor model was established to explore the role of circVCP in vivo. The target genes of circVCP or miR-9-5p were predicted by StarBase2.0. The target association among miR-9-5p and circVCP or NRP1 was confirmed using the luciferase assay and RNA-pull down assay.

RESULTS

circVCP was highly accumulated in exosomes derived from plasma of CRC patients and CRC cells. Additionally, exosomal circVCP derived from CRC cells promoted cell proliferation, migration and invasion by regulating the miR-9-5p/NRP1 axis, and induced macrophage M2 polarization and inhibited macrophage M1 polarization.

CONCLUSIONS

Over-expressed exosomal circVCP promoted the progression of CRC by regulating macrophage M1/M2 polarization through miR-9-5p/NRP1 axis. CircVCP may be a diagnostic biomarker and potential target for CRC therapy.

Identification of the biological function of miR-9 in spinal cord ischemia-reperfusion injury in rats

Spinal cord ischemia–reperfusion injury (SCII) is still a serious problem, and the mechanism is not fully elaborated. In the rat SCII model, qRT-PCR was applied to explore the altered expression of miR-9 (miR-9a-5p) after SCII. The biological function of miR-9 and its potential target genes based on bioinformatics analysis and experiment validation in SCII were explored next. Before the surgical procedure of SCII, miR-9 mimic and inhibitor were intrathecally infused. miR-9 mimic improved neurological function. In addition, miR-9 mimic reduced blood-spinal cord barrier (BSCB) disruption, inhibited apoptosis and decreased the expression of IL-6 and IL-1β after SCII. Gene Ontology (GO) analysis demonstrated that the potential target genes of miR-9 were notably enriched in several biological processes, such as “central nervous system development”, “regulation of growth” and “response to cytokine”. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that the potential target genes of miR-9 were significantly enriched in several signaling pathways, including “Notch signaling pathway”, “MAPK signaling pathway”, “Focal adhesion” and “Prolactin signaling pathway”. We further found that the protein expression of MAP2K3 and Notch2 were upregulated after SCII while miR-9 mimic reduced the increase of MAP2K3 and Notch2 protein. miR-9 mimic or MAP2K3 inhibitor reduced the release of IL-6 and IL-1β. miR-9 mimic or si-Notch2 reduced the increase of cleaved-caspase3. Moreover, MAP2K3 inhibitor and si-Notch2 reversed the effects of miR-9 inhibitor. In conclusion, overexpression of miR-9 improves neurological outcomes after SCII and might inhibit BSCB disruption, neuroinflammation, and apoptosis through MAP2K3-, or Notch2-mediated signaling pathway in SCII.

MicroRNA-205-5p inhibits skin cancer cell proliferation and increase drug sensitivity by targeting TNFAIP8

Tumor necrosis factor-α-induced protein 8 (TNFAIP8) is a member of the TIPE/TNFAIP8 family which regulates tumor growth and survival. Our goal is to delineate the detailed oncogenic role of TNFAIP8 in skin cancer development and progression. Here we demonstrated that higher expression of TNFAIP8 is associated with basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma development in patient tissues. Induction of TNFAIP8 expression by TNFα or by ectopic expression of TNFAIP8 in SCC or melanoma cell lines resulted in increased cell growth/proliferation. Conversely, silencing of TNFAIP8 decreased cell survival/cell migration in skin cancer cells. We also showed that miR-205-5p targets the 3'UTR of TNFAIP8 and inhibits TNFAIP8 expression. Moreover, miR-205-5p downregulates TNFAIP8 mediated cellular autophagy, increased sensitivity towards the B-RAF^V600E mutant kinase inhibitor vemurafenib, and induced cell apoptosis in melanoma cells. Collectively our data indicate that miR-205-5p acts as a tumor suppressor in skin cancer by targeting TNFAIP8.

Expression of TIPE family members in human colorectal cancer

The tumor necrosis factor α-induced protein 8 (TNFAIP8)-like (TIPE) protein family comprises four members, namely TNFAIP8, TIPE1, TIPE2 and TIPE3, which are involved in multiple processes in cancer. The current study aimed to investigate the expression patterns and potential clinical roles of the TIPE family members in human colorectal cancer (CRC). Paired tumor and adjacent tissue samples were collected from 49 patients with CRC, and the relative mRNA expression levels of the TIPE family members in these samples were evaluated by using reverse transcription-quantitative PCR, and the protein levels in five randomly selected pairs of tumor and adjacent tissue samples were detected by western blot analysis. The mRNA expression levels of the TIPE family members were significantly downregulated in CRC tumor tissues compared with those in the adjacent tissues; however, within each sample, TNFAIP8 and TIPE3 protein levels were only partially consistent with their mRNA levels. In addition, the mRNA expression levels between each pair of TIPE family members exhibited a positive linear relationship, and TIPE2 mRNA levels exhibited strong linear associations with those of TNFAIP8 and TIPE1. TNFAIP8 mRNA expression levels in tumor tissues were significantly associated with the tumor differentiation grade, and TIPE2 mRNA expression levels in tumor tissues were significantly associated with sex. TIPE1 and TIPE3 mRNA expression levels in tumor tissues exhibited no associations with patient clinicopathological characteristics. In addition, the mRNA expression patterns of the TIPE family members were analyzed using data from The Cancer Genome Atlas data set, and the results also demonstrated that TNFAIP8, TIPE2 and TIPE3 mRNA levels were downregulated in patients with colon adenocarcinoma compared with those in normal controls. These results provided evidence that the four members of the TIPE family may affect each other to mediate the carcinogenesis of CRC, and that TIPE2 may serve an important role in CRC.

SPATS2, negatively regulated by miR-145-5p, promotes hepatocellular carcinoma progression through regulating cell cycle

Spermatogenesis associated serine rich 2 (SPATS2) has been reported to contribute to the tumorigenesis of multiple malignancies. The molecular function of SPATS2 in hepatocellular carcinoma (HCC) is still not fully understood. In this study, we aimed to investigate the expression pattern and function roles of SPATS2 in HCC. The regulation of SPATS2 expression was also explored. We found that SPATS2 was highly expressed in HCC tissues in comparison with that in adjacent normal tissues. High expression of SPATS2 was associated with vascular invasion, advanced TNM stages, tumor multiplicity, and poor survival. Functionally, SPATS2 was found to promote the proliferation and metastasis of HCC cells both in vitro and in vivo, while knockdown of SPATS2 enhanced apoptosis and G1 arrest of HCC cells in vitro. Mechanistically, bioinformatics analysis revealed that MiR-145-5p directly targeted SPATS2 and functional rescue experiments verified that MiR-145-5p overexpression could abolish the effect of SPATS2 on the regulation of HCC malignant phenotype. Taken together, our findings suggest that SPATS2 functions as an oncogene in HCC. The MiR-145-5p/SPATS2 axis provides a novel mechanism underlying HCC progression and may serve as a potential therapeutic target for HCC.

Downregulation of miR-9 correlates with poor prognosis in colorectal cancer

INTRODUCTION

microRNAs (miRNAs) are frequently dysregulated in many human cancers including colorectal cancer (CRC) and are useful candidate biomarkers in liquid biopsy of cancer for their stability in the blood.

METHODS

We compared the expression of microRNA-9 (miR-9) in tissues (n = 357) and sera (n = 109) of CRC patients to determine whether miR-9 in serum reflects that in the cancer tissue in parallel. Also, we examined the miR-9 role in CRC by in vitro functional studies in four CRC cell lines.

RESULTS

On multivariate analysis of colorectal cancer tissues and sera, miR-9 low expressions were significantly associated pN stage (tissues; p < 0.01, serum; p = 0.013), and clinical stage (tissues; p < 0.01, serum; p = 0.031). Moreover, patients with low miR-9 expression had shorter survival than those with high miR-9 expression (log-rank test, tissue; p = 0.021, serum; p = 0.011). miR-9 level in serum reflects that in the tumor. The CRC cells with low miR-9 expression was significantly increased cell proliferation, migration, invasion and colony formation than cells with high miR-9 expression.

CONCLUSION

Serum miR-9 is an useful early detection marker in liquid biopsy of CRC and overexpression of miR-9 in CRC may be a novel prognostic marker as well.

MicroRNA-4268 inhibits cell proliferation via AKT/JNK signalling pathways by targeting Rab6B in human gastric cancer

MicroRNAs (miRNAs) play critical roles in the tumorigenesis and progression of gastric cancer (GC). However, the biological function of miR-4268 in GC and its mechanism remain unclear. In the present study, qTR-PCR found that the expression of miR-4268 was significantly downregulated in GC tissues and cell lines. The overexpression of miR-4268 inhibited GC cell proliferation and the cell cycle G1/S phase transition, and induced cell apoptosis. In contrast, inhibition of miR-4268 promoted cell proliferation and G1-S transition, and suppressed cell apoptosis. Further analyses revealed that miR-4268 expression was negatively correlated with Rab6B expression in GC tissues. Rab6B was verified to be a direct target of miR-4268. Notably, silencing Rab6B resulted in the same biological effects in GC cells as those induced by overexpression of miR-4268. Importantly, both miR-4268 overexpression and Rab6B silence inhibited the AKT/JNK signaling pathways, which modulated cell cycle regulators (Cyclin D1 and CDK4). In contrast, inhibition of miR-4268 promoted the AKT/JNK signaling pathways. MiR-4268 overexpression also promoted the p38 MAPK signaling pathway. Taken together, miR-4268 suppresses GC cell proliferation through inhibiting the AKT/JNK signaling pathways by targeting Rab6B and induces cell apoptosis through promoting the p38 MAPK signaling pathway. Our findings indicate a tumor-suppressor role of miR-4268 in GC pathogenesis and the potential of miR-4268 in GC theropy.

Tumor Necrosis Factor Alpha-Induced Proteins in Malignant Tumors: Progress and Prospects

Tumor necrosis factor (TNF) is the first cytokine used in tumor biotherapy, but TNF-related drugs are limited by the lack of specific targets. Tumor necrosis factor alpha-induced proteins (TNFAIPs), derived from TNF, is a protein family and participates in proliferation, invasion and metastasis of tumor cells. In order to better understand biological functions and potential roles of TNFAIPs in malignant tumors, this paper in the form of “Gene–Protein–Tumor correlation” summarizes the biological characteristics, physiological functions and mechanisms of TNFAIPs by searching National Center of Biotechnology Information, GeneCards, UniProt and STRING databases. The relationship between TNFAIPs and malignant tumors is analyzed, and protein–protein interaction diagram in members of TNFAIPs is drawn based on TNF for the first time. We find that TNF as a key factor is related to TNFAIP1, TNFAIP3, TNFAIP5, TNFAIP6, TNFAIP8 and TNFAIP9, which can be directly involved in activating TNFAIP1, TNFAIP5, TNFAIP8 and TNFAIP9. We confirm that the mechanism of TNFAIP1, TNFAIP2 and TNFAIP3 inducing tumors may be related to NF-κB signaling pathway, but the mechanism of tumor induction by other members of TNFAIPs is not clear. In the future, translational studies are needed to explore the mechanisms of TNF-TNFAIPs-tumors.

TIPE regulates VEGFR2 expression and promotes angiogenesis in colorectal cancer

Background: Metastasis is the leading cause of death in colorectal cancer (CRC) patients. It is regulated mainly by tumor cell angiogenesis, and angiogenesis is caused by the binding of vascular endothelial growth factor (VEGF) to vascular endothelial growth factor receptor 2 (VEGFR2). Tumor necrosis factor-α-induced protein 8 (TNFAIP8, hereto after TIPE) plays an important role in tumorigenesis, development, and prognosis. However, the relationship between TIPE and VEGFR2 in CRC angiogenesis and the mechanism of action remain unknown.

Method: In this study, we used quantitative real-time PCR, Western blotting and immunohistochemistry to detect TIPE and VEGFR2 expression in 55 specimens from CRC patients. We also used HCT116 CRC cells and human umbilical vein endothelial cells (HUVECs) for in vitro experiments by stably transducing shTIPE and shRNA control lentivirus into HCT116 cells, detecting VEGFR2 expression after TIPE knockdown and repurposing the culture supernatant as conditioned medium to stimulate angiogenesis of HUVECs. In vivo experiments with chicken chorioallantoic membranes (CAMs) and a nude mouse matrix subcutaneous tumor model were performed to validate the effects of TIPE on angiogenesis. Additionally, we analyzed the expression and phosphorylation levels of PDK1 and blocked PDK1 expression using inhibitors to determine whether TIPE-induced changes in VEGFR2-mediated angiogenesis acted via the PI3K-Akt pathway.

Results: We found that TIPE and VEGFR2 are highly expressed in CRC and act as oncogenes. TIPE knockdown also downregulated VEGFR2 expression, which resulted in simultaneous inhibition of cell proliferation, cell migration and angiogenesis. Then, in vivo experiments further demonstrated that TIPE promotes angiogenesis in CRC. Finally, we found that TIPE promotes VEGFR2-mediated angiogenesis by upregulating PDK1 expression and phosphorylation and that blocking PDK1 expression can inhibit this process.

Conclusion: TIPE promotes angiogenesis in CRC by regulating the expression of VEGFR2, which may be a target for antiangiogenic cancer therapy.

The long non-coding RNA TUG1-miR-9a-5p axis contributes to ischemic injuries by promoting cardiomyocyte apoptosis via targeting KLF5

Non-coding RNAs participate in many cardiac pathophysiological processes, including myocardial infarction (MI). Here we showed the interplay between long non-coding RNA taurine-upregulated gene 1 (lncR-TUG1), miR-9a-5p (miR-9) and Krüppel-like factor 5 (KLF5). LncR-TUG1 was upregulated in ischemic heart and in cultured cardiomyocytes exposed to H₂O₂. Knockdown of lncR-TUG1 markedly ameliorated impaired cardiac function of MI mice. Further study showed that lncR-TUG1 acted as a competitive endogenous RNA of miR-9, and silencing of lncR-TUG1 inhibited cardiomyocyte apoptosis by upregulating miR-9 expression. Furthermore, the miR-9 overexpression obviously prevented ischemia injury and significantly inhibited H₂O₂-induced cardiomyocyte apoptosis via inhibition of mitochondrial apoptotic pathway. KLF5, as a target gene of miR-9 by dual-luciferase reporter assay, was involved in the process of miR-9 in regulating cardiomyocyte apoptosis. Our data identified the KLF5 was downregulated by miR-9 overexpression and knockdown of KLF5 inhibited cardiomyocyte apoptosis induced by H₂O₂. MiR-9 exerts anti-cardiomyocyte apoptotic affects by targeting KLF5. Collectively, our data identify a novel function of lncR-TUG1/miR-9/KLF5 axis in regulating cardiomyocyte apoptosis that affects myocardial infarction progression.

MicroRNA-1269 promotes cell proliferation via the AKT signaling pathway by targeting RASSF9 in human gastric cancer

Background

MicroRNAs (miRNAs) play key roles in tumorigenesis and progression of gastric cancer (GC). miR-1269 has been reported to be upregulated in several cancers and plays a crucial role in carcinogenesis and cancer progression. However, the biological function of miR-1269 in human GC and its mechanism remain unclear and need to be further elucidated.

Methods

The expression of miR-1269 in GC tissues and cell lines was detected by quantitative real-time PCR (qRT-PCR). Target prediction programs (TargetScanHuman 7.2 and miRBase) and a dual-luciferase reporter assay were used to confirm that Ras-association domain family 9 (RASSF9) is a target gene of miR-1269. The expression of RASSF9 was measured by qRT-PCR and Western blotting in GC tissues. MTT and cell counting assays were used to explore the effect of miR-1269 on GC cell proliferation. The cell cycle and apoptosis were measured by flow cytometry. RASSF9 knockdown and overexpression were used to further verify the function of the target gene.

Results

We found that miR-1269 expression was upregulated in human GC tissues and cell lines. The overexpression of miR-1269 promoted GC cell proliferation and cell cycle G1-S transition and suppressed apoptosis. The inhibition of miR-1269 inhibited cell growth and G1-S transition and induced apoptosis. miR-1269 expression was inversely correlated with RASSF9 expression in GC tissues. RASSF9 was verified to be a direct target of miR-1269 by using a luciferase reporter assay. The overexpression of miR-1269 decreased RASSF9 expression at both the mRNA and protein levels, and the inhibition of miR-1269 increased RASSF9 expression. Importantly, silencing RASSF9 resulted in the same biological effects in GC cells as those induced by overexpression of miR-1269. Overexpression of RASSF9 reversed the effects of miR-1269 overexpression on GC cells. Both miR-1269 overexpression and RASSF9 silencing activated the AKT signaling pathway, which modulated cell cycle regulators (Cyclin D1 and CDK2). In contrast, inhibition of miR-1269 and RASSF9 overexpression inhibited the AKT signaling pathway. Moreover, miR-1269 and RASSF9 also regulated the Bax/Bcl-2 signaling pathway.

Conclusions

Our results demonstrate that miR-1269 promotes GC cell proliferation and cell cycle G1-S transition by activating the AKT signaling pathway and inhibiting cell apoptosis via regulation of the Bax/Bcl-2 signaling pathway by targeting RASSF9. Our findings indicate an oncogenic role of miR-1269 in GC pathogenesis and the potential use of miR-1269 in GC therapy.

MiR-9-5p Inhibits Glioblastoma Cells Proliferation Through Directly Targeting FOXP2 (Forkhead Box P2)

Glioblastoma (GBM) is the most malignant tumor in the central nervous system and the treatment is still unsatisfactory because the mechanism of the disease remains unclear. The abnormal expression of miRNAs and its target proteins play a crucial role in the development of glioblastoma. In this study, we demonstrated that high expression of miR-9-5p and low expression of forkhead box P2 (FOXP2) were related with better outcome in patients with GBM, and down regulated FOXP2 expression was able to inhibit glioma cells proliferation by cell cycle arrest. Furthermore, we found that FOXP2 was the target protein of miR-9-5p in luciferase assay. The results of this study suggest a novel regulatory mechanism that miR-9-5p can inhibit glioma cells proliferation by downregulating FOXP2.

PAK4, a target of miR-9-5p, promotes cell proliferation and inhibits apoptosis in colorectal cancer

Background

Colorectal cancer (CRC) is a leading cause of cancer-related death worldwide. P21-activated kinase 4 (PAK4) and miR-9-5p have emerged as attractive therapeutic targets in several tumor types, but in CRC, the regulation of their biological function and their target association remain unclear.

Methods

The expression of PAK4 in CRC tissues was determined using quantitative real-time PCR and immunohistochemistry analyses. The targeted regulation between miR-9-5p and PAK4 was predicted and confirmed with bioinformatics analysis and the dual-luciferase reporter assay. Functional experiments, including the MTT assay and flow cytometry, were performed to investigate the impact of PAK4 knockdown and miR-9-5p overexpression on cell proliferation and apoptosis in CRC cells.

Results

We found that the expression of PAK4 was upregulated in CRC tissues. PAK4 knockdown significantly suppressed cell proliferation and promoted apoptosis in cells of the CRC cell lines HCT116 and SW1116. We also found that miR-9-5p directly targeted the 3′-UTR of PAK4 mRNA and negatively regulated its expression. The degree of downregulation of miR-9-5p inversely correlated with PAK4 expression. Intriguingly, enforced expression of miR-9-5p suppressed cell proliferation and promoted apoptosis. This could be partially reversed by PAK4 overexpression.

Conclusion

These results suggest that miR-9-5p targeting of PAK4 could have therapeutic potential for CRC treatment.

miR-9-5p Suppresses Malignant Biological Behaviors of Human Gastric Cancer Cells by Negative Regulation of TNFAIP8L3

BACKGROUND

MicroRNA is essential for the malignant progression of human gastric cancer (GC), which is a leading cause of cancer deaths. However, the mechanism is still not so clear.

AIMS

In our present research, we investigated the effect of miR-9-5p in GC.

METHODS

We detected miR-9-5p expression in human gastric epithelial cell (GES-1) and GC cells (AGS, BGC-823, MKN-45, and MGC-803), plasma of normal or GC patients, as well as orthotopic xenograft mouse models by real-time PCR. The migration ability was detected by Transwell assays after miR-9-5p mimic or inhibitor transfection in GC cells.

RESULTS

Our results showed that miR-9-5p expression in GC cells and plasma was significantly decreased. miR-9-5p inhibited migration of GC cells by regulating TNFAIP8L3 directly. Low expression of miR-9-5p in GC patients hardly suppressed the migration mediated by TNFAIP8L3.

CONCLUSIONS

miR-9-5p, as a potential tumor suppressor gene, is closely related to the malignant progression of GC. Exploring the regulation between miR-9-5p and TNFAIP8L3 may provide a novel strategy for GC treatment.

Shiga-like toxin I exerts specific and potent anti-tumour efficacy against gastric cancer cell proliferation when driven by tumour-preferential Frizzled-7 promoter

OBJECTIVES

Tumour-targeted gene therapy is a promising approach for effective control of gastric cancer cell proliferation. Our study aims to develop a cancer therapy which combines tumour-targeting promoters with cytotoxins.

METHODS

The expression of globotriaosylceramide (Gb3), which is a Shiga-like toxin I (Stx1) receptor, was verified in gastric cancer compared with normal stomach tissues as assessed by flow cytometry and immunohistochemical analysis. We therefore constructed the recombinant pFZD7-Stx1 plasmid vectors with tumour-preferential Frizzled-7 promoter and Stx1. pFZD7-Stx1 was used to treat gastric cancer in vitro and in vivo. The gastric cancer cell proliferation and tumour growth were identified after the transfection with the pFZD7-Stx1.

RESULTS

Globotriaosylceramide was obviously increased in gastric cancer compared with normal stomach. The gastric cancer cell proliferation and tumour growth decreased significantly after the transfection with the pFZD7-Stx1.

CONCLUSION

Frizzled-7 promoter is preferentially active, and Gb3 is abundant in gastric cancer cells. Frizzled-7 promoter and Stx1 may be used to determine a novel and relatively specific and potent gastric cancer therapeutic strategy.

MiR-9 promotes tumorigenesis and angiogenesis and is activated by MYC and OCT4 in human glioma

BACKGROUND

Glioma, characterized by its undesirable prognosis and poor survival rate, is a serious threat to human health and lives. MicroRNA-9 (miR-9) is implicated in the regulation of multiple tumors, while the mechanisms underlying its aberrant expression and functional alterations in human glioma are still controversial.

METHODS

Expressions of miR-9 were measured in GEO database, patient specimens and glioma cell lines. Gain- and loss-of-function assays were applied to identify the effects of miR-9 on glioma cells and HUVECs in vitro and in vivo. Potential targets of miR-9 were predicted by bioinformatics and further verified via in vitro experiments. Transcriptional regulation of miR-9 by MYC and OCT4 was determined in glioma cells.

RESULTS

MiR-9 was frequently up-regulated in glioma specimens and cells, and could significantly enhance proliferation, migration and invasion of glioma cells. In addition, miR-9 could be secreted from glioma cells via exosomes and was then absorbed by vascular endothelial cells, leading to an increase in angiogenesis. COL18A1, THBS2, PTCH1 and PHD3 were verified as the direct targets of miR-9, which could elucidate the miR-9-induced malignant phenotypes in glioma cells. MYC and OCT4 were able to bind to the promoter region of miR-9 to trigger its transcription.

CONCLUSIONS

Our results highlight that miR-9 is pivotal for glioma pathogenesis and can be treated as a potential therapeutic target for glioma.

miR-9 Enhances the Chemosensitivity of AML Cells to Daunorubicin by Targeting the EIF5A2/MCL-1 Axis

Daunorubicin (Dnr) is at the forefront of acute myeloid leukemia (AML) therapy, but drug resistance poses a major threat to treatment success. MicroRNA (miR)-9 has been shown to have a pivotal role in AML development. However, little is known about the role of miR-9 in Dnr resistance in AML. We explored the potential role of miR-9 in Dnr resistance in AML cells and its mechanism of action. AML cell lines with high half-maximal inhibitory concentration to Dnr in vivo had significantly low miR-9 expression. miR-9 overexpresssion sensitized AML cells to Dnr, inhibited cell proliferation, and enhanced the ability of Dnr to induce apoptosis; miR-9 knockdown had the opposite effects. Mechanistic studies demonstrated that eukaryotic translation initiation factor 5A-2 (EIF5A2) was a putative target of miR-9, which was inversely correlated with the expression and role of miR-9 in AML cells. miR-9 improved the anti-tumor effects of Dnr by inhibiting myeloid cell leukemia-1 (MCL-1) expression, which was dependent on downregulation of EIF5A2 expression. These results suggest that miR-9 has an essential role in Dnr resistance in AML cells through inhibition of the EIF5A2/MCL-1 axis in AML cells. Our data highlight the potential application of miR-9 in chemotherapy for AML patients.

Oncogenic Role of Tumor Necrosis Factor α-Induced Protein 8 (TNFAIP8)

Tumor necrosis factor (TNF)-α-induced protein 8 (TNFAIP8) is a founding member of the TIPE family, which also includes TNFAIP8-like 1 (TIPE1), TNFAIP8-like 2 (TIPE2), and TNFAIP8-like 3 (TIPE3) proteins. Expression of TNFAIP8 is strongly associated with the development of various cancers including cancer of the prostate, liver, lung, breast, colon, esophagus, ovary, cervix, pancreas, and others. In human cancers, TNFAIP8 promotes cell proliferation, invasion, metastasis, drug resistance, autophagy, and tumorigenesis by inhibition of cell apoptosis. In order to better understand the molecular aspects, biological functions, and potential roles of TNFAIP8 in carcinogenesis, in this review, we focused on the expression, regulation, structural aspects, modifications/interactions, and oncogenic role of TNFAIP8 proteins in human cancers.

TNFAIP8 promotes cell growth by regulating the Hippo pathway in epithelial ovarian cancer

Tumor necrosis factor-α-induced protein 8 (TNFAIP8) is an independent prognostic factor for cancer-specific and disease-free survival in patients with epithelial ovarian cancer (EOC). However, the exact mechanism of the biological role of TNFAIP8 in EOC remains unclear. In the present study, a siRNA specifically targeting TNFAIP8 was prepared to knock down TNFAIP8 in EOC cells. Cell growth, colony formation, apoptosis, and cell cycle distribution in TNFAIP8-deficient EOC cells were determined. In addition, the underlying molecular mechanisms were investigated by western blot analysis and reverse transcription quantitative polymerase chain reaction assays. It was demonstrated that the knockdown of TNFAIP8 inhibited EOC cell growth and colony formation, along with increased levels of apoptosis and cell cycle arrest. The results of the western blot analysis suggested that TNFAIP8 inhibited the expression of phosphorylated yes-associated protein 1 (YAP) while promoting total and nuclear YAP expression, followed by the regulation of apoptosis and cell cycle checkpoint protein expression in EOC. Overexpression of YAP in EOC cells efficiently attenuated cell growth inhibition in TNFAIP8-deficient EOC cells. In addition, knockdown of TNFAIP8 significantly impaired EOC tumor growth in vivo. Collectively, the data from the present study suggested that TNFAIP8 is an oncogene and a novel therapeutic target for EOC.

TNFAIP8 promotes the proliferation and cisplatin chemoresistance of non-small cell lung cancer through MDM2/p53 pathway

Background

The highly refractory nature of non-small cell lung cancer (NSCLC) to chemotherapeutic drugs is an important factor resulting in its poor prognosis. Recent studies have revealed that tumour necrosis factor alpha-induced protein 8 (TNFAIP8) is involved in various biological and pathological processes of cells, but their underlying mechanisms in processes ranging from cancer development to drug resistance have not been fully elucidated.

Methods

TNFAIP8 expression in clinical NSCLC samples was examined through immunohistochemistry (IHC). After adjusting for patients’ characteristics with propensity score matching, Kaplan-Meier analysis and Cox regression analysis were performed for comparison of patients’ survival according to the TNFAIP8 level. Lentiviral transfection with TNFAIP8-specific shRNAs was used to establish stable TNFAIP8 knockdown (TNFAIP8 KD) NCI-H460, A549 and cis-diamminedichloroplatinum II resistant A549 (A549/cDDP) cell lines. Cell proliferation and viability were assessed by CCK-8 assay. Cell cycle was examined by flow cytometry. Multiple pathways regulated by TNFAIP8 KD were revealed by microarray analysis.

Results

We found that high TNFAIP8 expression was associated with advanced pT stage, advanced pTNM stage, lymph node metastasis and unfavourable survival in NSCLC patients. TNFAIP8 shRNAs reduced in vitro cancer cell proliferation and in vivo tumor growth. Additionally, TNFAIP8 KD increased the sensitivity of NSCLC cells to cisplatin in vitro and in vivo. Conversely, up-regulation of TNFAIP8 promoted the proliferation and drug resistance to cisplatin of NSCLC cells. TNFAIP8 influences cancer progression pathways involving the MDM2/p53 pathway. Indeed, we observed that TNFAIP8 KD mediated the MDM2 downregulation and the p53 ubiquitination, thereby decreasing the degradation of p53 protein. shRNA p53 reversed TNFAIP8 shRNA-mediated regulation of cell proliferation, cell cycle, cisplatin sensitivity, and expression levels of RAD51, a DNA repair gene.

Conclusion

Our work uncovers a hitherto unappreciated role of TNFAIP8 in NSCLC proliferation and cisplatin chemoresistance that is mediated through the MDM2/p53 pathway. These findings might offer potential therapeutic targets for reversing cisplatin resistance in NSCLC patients with high TNFAIP8 expression.

Electronic supplementary material

The online version of this article (10.1186/s12964-018-0254-x) contains supplementary material, which is available to authorized users.

Tumor Necrosis Factor-α Induced Protein 8: Pathophysiology, Clinical Significance, and Regulatory Mechanism

Tumor necrosis factor-α-induced protein-8 (TNFAIP8) is the earliest discovered component of TNFAIP8 family [tumor necrosis factor-α-induced protein-8 like (TIPE) family]. TNFAIP8 contains a putative death effector domain (DED) homologous to DED II in FLIP (Fas-associated death domain-like interleukin-1β-converting enzyme-inhibitory protein), which may affect cell survival/death process. Recently, it has been demonstrated that TNFAIP8 could inhibit apoptosis and autophagy in various types of cells. Moreover, TNFAIP8 level fluctuated evidently in patients with inflammatory, malignant, and autoimmune diseases, indicating that it might be an anti-apoptotic and oncogenetic protein. Herein we will review the discovery, gene/protein structure, pathophysiological functions, and clinical significance of TNFAIP8 together with its potential regulatory mechanism.

microRNA-9 functions as a tumor suppressor in colorectal cancer by targeting CXCR4

MicroRNAs (miRs) dysregulation has been proven to play a crucial role in the initiation and progression of colorectal cancer (CRC). miR-9 functions as a tumor suppressor in many cancer types, including CRC. However, the precise role of miR-9 and the underlying molecular mechanisms that miR-9 involves in CRC progression remain largely unknown. In this study, it was reported that miR-9 had lower expression in CRC tissue samples than in those matched adjacent non-tumor tissues. Deregulated miR-9 expression was inverse correlated with the TNM stage, lymph node metastasis, and prognosis of CRC patients. Ectopic miR-9 expression suppressed CRC cell proliferation, migration, and invasion. Dual-Luciferase Reporter Assay confirmed that C-X-C Motif Chemokine Receptor 4 (CXCR4) was a direct miR-9 target, and the effects of miR-9 were mimicked through CXCR4 depletion in vitro. CXCR4 rescue experiments further verified that CXCR4 is a functional target of miR-9. Animal xenograft assays also provided evidence that miR-9 functions as a tumor suppressor via targeting CXCR4 in vivo. Mechanistically, miR-9 overexpression or CXCR4 knockdown influenced cell proliferation and epithelial-mesenchymal transition (EMT). Results suggest that miR-9 acts as a tumor suppressor in CRC progression by regulating CXCR4.

MicroRNA‑382 inhibits cell proliferation and invasion of retinoblastoma by targeting BDNF‑mediated PI3K/AKT signalling pathway

It has previously been demonstrated that multiple microRNAs (miRNAs or miRs) are aberrantly expressed in retinoblastoma (RB) and contribute to RB initiation and progression. miR‑382 has been revealed to be aberrantly expressed and therefore exhibits a key role in the progression of various types of cancer. However, the expression pattern, functional roles and underlying molecular mechanism of miR‑382 in RB remain unknown. The present study investigated the expression levels of miR‑382 and its effects on RB cells and the underlying regulatory mechanism of its action. It was demonstrated that miR‑382 was downregulated in RB tissues and cell lines. Upregulation of miR‑382 inhibited RB cell proliferation and invasion in vitro. Additionally, brain‑derived neurotrophic factor (BDNF) was identified as a novel target of miR‑382 in RB. BDNF was upregulated in RB tissues and negatively associated with miR‑382 expression levels. Furthermore, BDNF overexpression rescued the tumour‑suppressing effects on RB cells induced by miR‑382. miR‑382 inactivated the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signalling pathway in RB. These findings suggested that miR‑382 serves as a tumour suppressor in RB, in part, by targeting the BDNF‑mediated PI3K/AKT signalling pathway. The results of the present study suggest a potential therapeutic strategy for treating RB patients in the future.

MicroRNA-9 inhibits the gastric cancer cell proliferation by targeting TNFAIP8

BACKGROUND AND OBJECTIVES

MicroRNA-9 is frequently dysregulated in many human carcinoma types, including gastric cancer (GC). Previous studies demonstrated that the expression of TNFAIP8 in GC is correlated with tumour occurrence, development, invasion, metastasis and prognosis. However, till now, the relationship between MicroRNA-9 and TNFAIP8 in GC has not been reported.

MATERIALS AND METHODS

Levels of miR-9 and TNFAIP8 expression in GC tissues and in human GC cell lines were studied using qualitative real-time PCR (qRT-PCR) and Western blotting. Cell viability was detected using the CCK-8 and clone formation assays. A dual-luciferase reporter system was used to confirm the target gene of miR-9.

RESULTS

We found that the expression level of MicroRNA-9 in GC tissues and cell lines was significantly lower than that in adjacent non-cancerous tissues and human immortalized gastric epithelial cell (GES) line, respectively. In addition, overexpression of MicroRNA-9 markedly inhibited GC cell proliferation in vitro and tumour growth in vivo. Further experiments revealed that TNFAIP8 was a direct and functional target of MicroRNA-9 in GC and overexpression of MicroRNA-9 obviously down-regulated the expression of TNFAIP8, which was involved in the gastric carcinogenesis and cancer progression.

CONCLUSION

Our results suggested that MicroRNA-9-TNFAIP8 might represent a promising diagnostic biomarker for GC patients and could be a potential therapeutic target in the prevention and treatment of GC.