MicroRNA-605 functions as a tumor suppressor by targeting INPP4B in melanoma

Small Nucleolar Derived RNAs as Regulators of Human Cancer

In the past decade, RNA fragments derived from full-length small nucleolar RNAs (snoRNAs) have been shown to be specifically excised and functional. These sno-derived RNAs (sdRNAs) have been implicated as gene regulators in a multitude of cancers, controlling a variety of genes post-transcriptionally via association with the RNA-induced silencing complex (RISC). In this review, we have summarized the literature connecting sdRNAs to cancer gene regulation. SdRNAs possess miRNA-like functions and are able to fill the role of tumor-suppressing or tumor-promoting RNAs in a tissue context-dependent manner. Indeed, there are many miRNAs that are actually derived from snoRNA transcripts, meaning that they are truly sdRNAs and as such are included in this review. As sdRNAs are frequently discarded from ncRNA analyses, we emphasize that sdRNAs are functionally relevant gene regulators and likely represent an overlooked subclass of miRNAs. Based on the evidence provided by the papers reviewed here, we propose that sdRNAs deserve more extensive study to better understand their underlying biology and to identify previously overlooked biomarkers and therapeutic targets for a multitude of human cancers.

Context-Dependent Regulation of Gene Expression by Non-Canonical Small RNAs

In recent functional genomics studies, a large number of non-coding RNAs have been identified. It has become increasingly apparent that noncoding RNAs are crucial players in a wide range of cellular and physiological functions. They have been shown to modulate gene expression on different levels, including transcription, post-transcriptional processing, and translation. This review aims to highlight the diverse mechanisms of the regulation of gene expression by small noncoding RNAs in different conditions and different types of human cells. For this purpose, various cellular functions of microRNAs (miRNAs), circular RNAs (circRNAs), snoRNA-derived small RNAs (sdRNAs) and tRNA-derived fragments (tRFs) will be exemplified, with particular emphasis on the diversity of their occurrence and on the effects on gene expression in different stress conditions and diseased cell types. The synthesis and effect on gene expression of these noncoding RNAs varies in different cell types and may depend on environmental conditions such as different stresses. Moreover, noncoding RNAs play important roles in many diseases, including cancer, neurodegenerative disorders, and viral infections.

Prostanoid Signaling in Cancers: Expression and Regulation Patterns of Enzymes and Receptors

Cancer-associated disturbance of prostanoid signaling provides an aberrant accumulation of prostanoids. This signaling consists of 19 target genes, encoding metabolic enzymes and G-protein-coupled receptors, and prostanoids (prostacyclin, thromboxane, and prostaglandins E2, F2α, D2, H2). The study addresses the systems biology analysis of target genes in 24 solid tumors using a data mining pipeline. We analyzed differential expression patterns of genes and proteins, promoter methylation status as well as tissue-specific master regulators and microRNAs. Tumor types were clustered into several groups according to gene expression patterns. Target genes were characterized as low mutated in tumors, with the exception of melanoma. We found at least six ubiquitin ligases and eight protein kinases that post-translationally modified the most connected proteins PTGES3 and PTGIS. Models of regulation of PTGIS and PTGIR gene expression in lung and uterine cancers were suggested. For the first time, we found associations between the patient’s overall survival rates with nine multigene transcriptomics signatures in eight tumors. Expression patterns of each of the six target genes have predictive value with respect to cytostatic therapy response. One of the consequences of the study is an assumption of prostanoid-dependent (or independent) tumor phenotypes. Thus, pharmacologic targeting the prostanoid signaling could be a probable additional anticancer strategy.

The INPP4B paradox: Like PTEN, but different

Cancer is a complex and heterogeneous disease marked by the dysregulation of cancer driver genes historically classified as oncogenes or tumour suppressors according to their ability to promote or inhibit tumour development and growth, respectively. Certain genes display both oncogenic and tumour suppressor functions depending on the biological context, and as such have been termed dual-role cancer driver genes. However, because of their context-dependent behaviour, the tumourigenic mechanism of many dual-role genes is elusive and remains a significant knowledge gap in our effort to understand and treat cancer. Inositol polyphosphate 4-phosphatase type II (INPP4B) is an emerging dual-role cancer driver gene, primarily known for its role as a negative regulator of the phosphoinositide 3-kinase (PI3K)/AKT signalling pathway. In response to growth factor stimulation, class I PI3K generates PtdIns(3,4,5)P₃ at the plasma membrane. PtdIns(3,4,5)P₃ can be hydrolysed by inositol polyphosphate 5-phosphatases to generate PtdIns(3,4)P₂, which, together with PtdIns(3,4,5)P₃, facilitates the activation of AKT to promote cell proliferation, survival, migration, and metabolism. Phosphatase and tensin homology on chromosome 10 (PTEN) and INPP4B are dual-specificity phosphatases that hydrolyse PtdIns(3,4,5)P₃ and PtdIns(3,4)P₂, respectively, and thus negatively regulate PI3K/AKT signalling. PTEN is a bona fide tumour suppressor that is frequently lost in human tumours. INPP4B was initially characterised as a tumour suppressor akin to PTEN, and has been implicated as such in a number of cancers, including prostate, thyroid, and basal-like breast cancers. However, evidence has since emerged revealing INPP4B as a paradoxical oncogene in several malignancies, with increased INPP4B expression reported in AML, melanoma and colon cancers among others. Although the tumour suppressive function of INPP4B has been mostly ascribed to its ability to negatively regulate PI3K/AKT signalling, its oncogenic function remains less clear, with proposed mechanisms including promotion of PtdIns(3)P-dependent SGK3 signalling, inhibition of PTEN-dependent AKT activation, and enhancing DNA repair mechanisms to confer chemoresistance. Nevertheless, research is ongoing to identify the factors that dictate the tumourigenic output of INPP4B in different human cancers. In this review we discuss the dualistic role that INPP4B plays in the context of cancer development, progression and treatment, drawing comparisons to PTEN to explore how their similarities and, importantly, their differences may account for their diverging roles in tumourigenesis.

MicroRNA Signature in Melanoma: Biomarkers and Therapeutic Targets

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

lncRNA RAET1K Promotes the Progression of Acute Myeloid Leukemia by Targeting miR-503-5p/INPP4B Axis

Background

Although long non-coding RNA (lncRNA) RAET1K has been observed to be abnormally expressed in patients with various cancers, its role and molecular mechanism in acute myeloid leukemia (AML) remain unclear.

Methods

The expression of RAET1K and miR-503-5p in bone marrow tissues and cell lines was detected by qRT-PCR. Cell proliferation was evaluated by cell counting kit-8 and 5-ethynyl-20-deoxyuridine (EdU) staining assay. Cell invasion and migration were detected by transwell assay. Cell apoptosis was evaluated by flow cytometry. The relationship between RAET1K and miR-503-5p, as well as miR-503-5p and INPP4B, was determined by luciferase reporter assay and RNA immunoprecipitation (RIP) assay. In addition, the tumorigenesis of leukemia cells was evaluated by using a xenograft mouse model in vivo.

Results

RAET1K was significantly upregulated and miR-503-5p was markedly downregulated in bone marrow tissues and cell lines (HL-60 and THP-1). Silencing of RAET1K (si-RAET1K) and overexpression of miR-503-5p inhibited cell proliferation, migration, and invasion but promoted apoptosis of HL-60 and THP-1 cells. RAET1K functioned as a sponge of miR-503-5p, and miR-503-5p inhibitor obviously attenuated the effect of si-RAET1K on AML progression in vitro. INPP4B was identified as a target of miR-503-5p, and INPP4B overexpression obviously reversed the effect of miR-503-5p mimics on cell proliferation, migration, invasion, and apoptosis of HL-60 and THP-1 cells in vitro. Knockdown of RAET1K effectively inhibited the tumorigenesis of leukemia cells in vivo.

Conclusion

Our results demonstrated that RAET1K/miR-503-5p/INPP4B axis contributed to AML progression, suggesting that RAET1K might be a potential target for the treatment of AML.

Export Control: Post-transcriptional Regulation of the COPII Trafficking Pathway

The coat protein complex II (COPII) mediates forward trafficking of protein and lipid cargoes from the endoplasmic reticulum. COPII is an ancient and essential pathway in all eukaryotes and COPII dysfunction underlies a range of human diseases. Despite this broad significance, major aspects of COPII trafficking remain incompletely understood. For example, while the biochemical features of COPII vesicle formation are relatively well characterized, much less is known about how the COPII system dynamically adjusts its activity to changing physiologic cues or stresses. Recently, post-transcriptional mechanisms have emerged as a major mode of COPII regulation. Here, we review the current literature on how post-transcriptional events, and especially post-translational modifications, govern the COPII pathway.

Identification of 6 Hub Proteins and Protein Risk Signature of Colorectal Cancer

Background

Colorectal cancer (CRC) is the second most common cause of cancer death in the United States and the third most common cancer globally. The incidence of CRC tends to be younger, and we urgently need a reliable prognostic assessment strategy.

Methods

Protein expression profile and clinical information of 390 CRC patients/samples were downloaded from the TCPA and TCGA database, respectively. The Kaplan-Meier, Cox regression, and Pearson correlation analysis were applied in this study.

Results

Based on the TCPA and TCGA database, we screened 6 hub proteins and first constructed protein risk signature, all of which were significantly associated with CRC patients' overall survival (OS). The risk score was an independent prognostic factor and significantly related with the size of the tumor in situ (T). 6 hub proteins were differentially expressed in cancer and normal tissues and in different CRC stages, which were validated at the ONCOMINE database. Next, 40 coexpressed proteins of 6 hub proteins were extracted from the TCPA database. In the protein-protein interaction (PPI) network, HER1, HER2, and CTNNB1 were at the center. Function enrichment analysis illustrated that 46 proteins were mainly involved in the EGFR (HER1) tyrosine kinase inhibitor resistance pathway.

Conclusion

Studies indicated that 6 hub proteins might be considered as new targets for CRC therapies, and the protein risk signature can be used to predict the OS of CRC patients.

Downregulation of microRNA-605 indicates poor prognosis and promotes the progression of osteosarcoma

Osteosarcoma (OS) is a type of primary bone tumor, which is one of the leading causes of cancer-related death. MicroRNA (miR)-605 has been demonstrated to act as a prognostic biomarker and therapeutic target in various cancers, such as breast cancer and non-small cell lung cancer, but its function in OS remains unclear. The aim of the present study was to investigate the prognostic value of miR-605 in patients with OS by evaluating its expression levels and to explore the biological function of miR-605 in OS progression. For this purpose, tumor tissues and adjacent normal tissues were collected from OS patients, and the expression of miR-605 in the collected tissues and OS MG63, U2OS, HOS, and SAOS-2 cell lines was detected by quantitative real-time PCR. The prognostic value of miR-605 was evaluated by Kaplan-Meier survival curves and Cox regression analysis. The effects of miR-605 on OS cell proliferation, migration and invasion were analyzed by the CCK-8 and transwell assays, respectively. The results of the present study revealed that miR-605 was significantly downregulated in OS tissues compared with adjacent normal tissues, which was associated with the clinical stage and distant metastasis of patients. Additionally, the downregulation of miR-605 predicted the poor prognosis of patients with OS and served as an independent prognostic indicator. The downregulation of miR-605 enhanced cell proliferation, migration, and invasion of OS cells, which suggested that miR-605 may be involved in the progression of OS. The findings of the present study provide a new therapeutic target for the treatment of patients with OS.

MicroRNA-3666 Suppresses Cell Growth in Head and Neck Squamous Cell Carcinoma Through Inhibition of PFKFB3-Mediated Warburg Effect

Purpose

MicroRNA-3666 (miR-3666) is aberrantly expressed and plays critical roles in numerous human tumors. However, the expression pattern, biological role, and mechanisms of action of miR-3666 in head and neck squamous cell carcinoma (HNSCC) remain unknown. Therefore, we attempted to determine the expression status and function of miR-3666 in HNSCC and to explore the underlying mechanisms in detail.

Methods

In this study, quantitative real-time polymerase chain reaction was carried out to measure the expression of miR-3666 HNSCC tissues. A series of experiments, including a Cell Counting Kit-8 assay, colony formation assay, BrdU incorporation and apoptosis analysis, were applied to test whether miR-3666 affects the growth of HNSCC cells. Glucose uptake and lactate production measurements and extracellular acidification and oxygen consumption rate assays were conducted to determine the effect of miR-3666 on glycolysis.

Results

We found that miR-3666 showed a decreased expression in HNSCC tissues. Further functional studies demonstrated that miR-3666 inhibited the growth of HNSCC cells by suppressing cell proliferation and promoting apoptosis. Bioinformatics analysis and luciferase reporter assays identified phosphofructokinase-2/fructose-2,6-bisphosphatase 3 (PFKFB3), a key enzyme regulating glycolysis, as a direct target of miR-3666. Through inhibition of PFKFB3, miR-3666 decreased glycolysis in HNSCC cells by reducing the production of F2,6BP. Importantly, glycolysis suppression caused by miR-3666 was found to be required for its inhibitory effect on HNSCC cell growth.

Conclusion

Our data suggest that miR-3666 functions as a tumor suppressor by decreasing the rate of glycolysis through inhibition of PFKFB3 activity, and this miRNA may present a potential candidate for HNSCC therapy.

The miRNAs Role in Melanoma and in Its Resistance to Therapy

Melanoma is the less common but the most malignant skin cancer. Since the survival rate of melanoma metastasis is about 10–15%, many different studies have been carried out in order to find a more effective treatment. Although the development of target-based therapies and immunotherapeutic strategies has improved chances for patient survival, melanoma treatment still remains a big challenge for oncologists. Here, we collect recent data about the emerging role of melanoma-associated microRNAs (miRNAs) currently available treatments, and their involvement in drug resistance. We also reviewed miRNAs as prognostic factors, because of their chemical stability and resistance to RNase activity, in melanoma progression. Moreover, despite miRNAs being considered small conserved regulators with the limitation of target specificity, we outline the dual role of melanoma-associated miRNAs, as oncogenic and/or tumor suppressive factors, compared to other tumors.

Investigating the duality of Inpp4b function in the cellular transformation of mouse fibroblasts

Inositol Polyphosphate 4-Phosphatase, Type II (INPP4B) is a tumour suppressor in breast, ovarian, prostate, thyroid and other cancers, attributed to its ability to reduce oncogenic Akt-signaling. However, emerging studies show that INPP4B also has tumour-promoting properties in cancers including acute myeloid leukemia, colon cancer, melanoma and breast cancer. Together these findings suggest that INPP4B may be a context dependent cancer gene. Whether INPP4B functions solely in a tumour suppressing or tumour promoting manner, or both in non-transformed cells is currently not clear. In this study, consequences of deficiency and overexpression of INPP4B on cellular transformation was investigated using a mouse embryonic fibroblast (MEF) model of cellular transformation. We observed that neither deficiency nor overexpression of INPP4B was sufficient to induce neoplastic transformation, alone or in combination with H-Ras ^V12 or E1A overexpression. However, Inpp4b-deficiency did cooperate with SV40 T-Large-mediated cellular transformation, a finding which was associated with increased phosphorylated-Akt levels. Transformation and phosphorylated-Akt levels were dampened upon overexpression of INPP4B in SV40 T-Large-MEF. Together, our findings support a model where INPP4B function suppresses transformation mediated by SV40 T-Large, but is inconsequential for Ras and E1A mediated transformation.

microRNA-605 directly targets SOX9 to alleviate the aggressive phenotypes of glioblastoma multiforme cell lines by deactivating the PI3K/Akt pathway

Background

Aberrant microRNA (miRNA) expression has been widely reported to play a crucial role in the progression and development of glioblastoma (GBM). miR-605 has been identified as a tumor-suppressing miRNA in several types of human cancers. Nevertheless, the expression profile and detailed roles of miR-605 in GBM remain unclear and need to be further elucidated.

Materials and methods

RT-qPCR analysis was utilized for the determination of miR-605 expression in GBM tissues and cell lines. In addition, CCK-8 assay, transwell migration and invasion assays, as well as sub-cutaneous xenograft mouse models were utilized to evaluate the effects of miR-605 upregulation in GBM cells. Notably, the potential mechanisms underlying the activity of miR-605 in the malignant phenotypes of GBM were explored.

Results

We observed that expression of miR-605 was reduced in GBM tissues and cell lines. Decreased miR-605 expression exhibited significant correlation with KPS score. The overall survival rate in GBM patients with low miR-605 expression was lower than that of patients with high miR-605 expression. Increased miR-605 expression suppressed the proliferation, migration, and invasion of U251 and T98 cells. In addition, miR-605 upregulation impaired tumor growth in vivo. Furthermore, SRY-Box 9 (SOX9) was identified as a direct target gene of miR-605 in U251 and T98 cells. SOX9 expression was shown to exhibit an inverse correlation with miR-605 expression in GBM tissues. Moreover, silencing of SOX9 expression mimicked the tumor-suppressing roles of miR-605 in U251 and T98 cells, while SOX9 restoration rescued the suppressive effects of miR-605 overexpression in the same. Notably, miR-605 suppressed the PI3K/Akt pathway in GBM in vitro and in vivo.

Conclusion

These results demonstrated that miR-605 acts as a tumor suppressor in the development of GBM by directly targeting SOX9 and inhibiting the activation of the PI3K/Akt pathway, suggesting its potential role as a therapeutic target for GBM.

microRNA-605 inhibits the oncogenicity of non-small-cell lung cancer by directly targeting Forkhead Box P1

Background and aims: microRNA-605 (miR-605) is dysregulated in multiple cancers and plays crucial roles in regulating cancer progression. However, little is known about the expression pattern and detailed roles of miR-605 in non-small-cell lung cancer (NSCLC). Thus, in this study, we evaluated miR-605 expression in NSCLC along with its clinical significance. More importantly, the detailed roles and the underlying molecular mechanisms of miR-605 in NSCLC were explored.

Material and methods: Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was employed to detect miR-605 expression in NSCLC tissues and cell lines. A series of experiments were performed to determine the effects of miR-605 upregulation on NSCLC cell proliferation, apoptosis, migration and invasion in vitro and tumor growth in vivo. In addition, the downstream regulatory mechanisms of miR‐605 action in NSCLC cells were explored.

Results: Decreased expression of miR-605 was frequently detected in NSCLC tissues and cell lines. Low expression of miR-605 was significantly correlated with the tumor size, TNM stage, and distane metastasis in NSCLC patients. Exogenous miR-605 expression inhibited proliferation, increased apoptosis, and inhibited metastasis of NSCLC cells in vitro. Additionally, miR-605 overexpression hindered the growth of NSCLC cells in vivo. Furthermore, Forkhead Box P1 (FOXP1) was identified as a direct target gene of miR-605 in NSCLC cells. Moreover, FOXP1 was highly expressed in NSCLC cells and showed an inverse correlation with miR-605 expression levels. Besides, silencing of FOXP1 simulated roles similar to miR-605 upregulation in NSCLC cells. FOXP1 reintroduction partially abolished the anticancer effects of miR-605 in NSCLC cells.

Conclusion: Our results revealed that miR-605 inhibited the oncogenicity of NSCLC cells in vitro and in vivo by directly targeting FOXP1, suggesting the importance of the miR-605/FOXP1 pathway in the malignant development of NSCLC.

INPP4B promotes colorectal cancer cell proliferation by activating mTORC1 signaling and cap-dependent translation

Background and objective

Inositol polyphosphate 4-phosphatase type II (INPP4B) is over-expressed in CRC tissues, and emerges as an oncogene. However, the mechanism by which INPP4B regulates CRC cell proliferation remains largely unclear. In this study, we aimed to investigate the regulatory mechanisms of INPP4B in CRC.

Materials and methods

The expression levels of mRNA were detected by qRT-PCR. The expression levels of protein were determined by Western blot. Cell Counting Kit-8 (CCK-8) assays and BrdU incorporation assays were performed to evaluate cell proliferation abilities. Bicistronic luciferase assays and the m7GTP pull down assay were performed to measure the cap-dependent translation in cells.

Results

INPP4B promotes CRC cell proliferation by increasing mTORC1 activity. Furthermore, it was shown that the activation of mTORC1 signaling by INPP4B led to increased cap-dependent translation, which is essential for INPP4B-mediated CRC cell proliferation. Finally, it was demonstrated that increased AKT and serum and glucocorticoid-inducible kinase 1 activity contributed to the activation of cap-dependent translation induced by INPP4B.

Conclusion

Collectively, the present study reveals INPP4B promotes colorectal cancer cell proliferation by activating mTORC1 signaling and cap-dependent translation.

IRF2-INPP4B-mediated autophagy suppresses apoptosis in acute myeloid leukemia cells

BACKGROUND

The present study aimed to investigate the underlying role of interferon-regulatory factor 2 (IRF2)-inositol polyphosphate-4-phosphatase, type-II (INPP4B) axis in the regulation of autophagy in acute myeloid leukemia (AML) cells.

METHODS

Quantitative real time PCR (QRT-PCR) and western blot were performed to determine the expression levels of IRF2, INPP4B and autophagy-related markers in AML cell lines. Autophagy was assessed by elevated Beclin-1 expression, the conversion of light chain 3 (LC3)-I to LC3-II, downregulated p62 expression and green fluorescent protein (GFP)-LC3 puncta formation. The colony formation and apoptosis assays were performed to determine the effects of IRF2 and INPP4B on the growth of AML cells.

RESULTS

IRF2 and INPP4B were highly expressed in AML cell lines, and were positively correlated with autophagy-related proteins. Overexpression of IRF2 or INPP4B stimulated autophagy of AML cells, whereas inhibition of IRF2 or INPP4B resulted in the attenuation of autophagy. More importantly, IRF2 or INPP4B overexpression reversed autophagy inhibitor, 3-methyladenine (3-MA)-induced proliferation-inhibitory and pro-apoptotic effects, while IRF2 or INPP4B silencing overturned the proliferation-promoting and anti-apoptotic effects of autophagy activator rapamycin.

CONCLUSION

IRF2-INPP4B signaling axis attenuated apoptosis through induction of autophagy in AML cells.

The role of microRNAs in prostate cancer migration, invasion, and metastasis

Prostate cancer (PCa) is considered the most prevalent malignancy and the second major cause of cancer-related death in males from Western countries. PCa exhibits variable clinical pictures, ranging from dormant to highly metastatic cancer. PCa suffers from poor prognosis and diagnosis markers, and novel biomarkers are required to define disease stages and to design appropriate therapeutic approach by considering the possible genomic and epigenomic differences. MicroRNAs (miRNAs) comprise a class of small noncoding RNAs, which have remarkable functions in cell formation, differentiation, and cancer development and contribute in these processes through controlling the expressions of protein-coding genes by repressing translation or breaking down the messenger RNA in a sequence-specific method. miRNAs in cancer are able to reflect informative data about the current status of disease and this might benefit PCa prognosis and diagnosis since that is concerned to PCa patients and we intend to highlight it in this paper.

Lack of Association between miR-605 rs2043556 Polymorphism and Overall Cancer Risk: A Meta-analysis of Case-control Studies

Growing evidence propose an association between miRNA polymorphisms and cancer susceptibility. This study aimed to examine the impact of miR-605 rs2043556 polymorphism on cancer risk through a meta-analysis based on 3198 cancer cases and 4943 controls. Eligible studies were retrieved by searching Web of Science, PubMed, Scopus, and Google Scholar databases up to August 27, 2018. The pooled Odds Ratios (ORs) with 95% Confidence Intervals (CIs) were calculated using a random-effect model to estimate the strength of association between rs2043556 variant of miR-605 and cancer risk. Overall, no significant association was found between miR-605 rs2043556 polymorphism and cancer risk in heterozygous codominant (OR=0.93, 95% CI=0.76-1.13, p=0.44, AG vs. AA), homozygous codominant (OR=1.01, 95%CI=0.78-1.30, p=0.94, GG vs. AA), dominant (OR=0.95, 95% CI=0.79-1.13, p=0.55, AG+GG vs. AA), recessive (OR=1.07, 95%CI=0.84-1.38, p=0.57, GG vs. AG+AA), overdominant (OR=0.93, 95% CI=0.76-1.12, p=0.43, AG vs. GG+AA), and allele (OR=0.98, 95% CI=0.87-1.10, p=0.73, G vs. A) genetic models tested. Stratified analysis by cancer type revealed that the rs2043556 variant was not associated with digestive tract cancer, breast cancer, gastric cancer as well as lung cancer. Taken together, the findings of this meta-analysis did not support an association between miR-605 rs2043556 polymorphism and cancer susceptibility.

LncRNA SNHG5 promotes the progression of osteosarcoma by sponging the miR-212-3p/SGK3 axis

Background

Long non-coding RNA (lncRNA) SNHG5 has been found to play an important role in tumors. Nevertheless, the function and mechanism of lncRNA SNHG5 in osteosarcoma (OS) remains unclear. The purpose of this study was to investigate whether lncRNA SNHG5 can regulate the occurrence and development of OS cells.

Methods

We performed quantitative real time PCR to detect the expression of lncRNA SNHG5 in OS cells. 143B, MG63 (knockdown) and U2OS, U2R (overexpression) cell lines were chosen for the function study of SNHG5. The effect of SNHG5, miR-212-3p, and SGK3 in OS cells was explored by MTT assays, clony formation, flow cytometry, transwell assays, wound healing assays, and cell spreading assays. Quantitative real-time PCR, Western blot analysis and luciferase assays were used to detect the interaction between lncRNA SNHG5 and miR-212-3p.

Results

In this study, knockdown of lncRNA SNHG5 suppressed the growth and metastasis of OS cells, whereas the overexpression of SNHG5 produced an opposite result. Mechanistically, lncRNA SNHG5 functions as a sponger against miR-212-3p and suppresses the miR-212-3p/SGK3 signaling pathway. Introduction of miR-212-3p mimics or inhibitors reverses SNHG5 overexpression or silences the exerted tumor promoting or suppressing effect. In addition, our results showed that the function of SNHG5 can be rescued by miR-212-3p and can regulate the growth and metastasis of OS cells via SGK3, the downstream target of miR-212-3p.

Conclusions

In summary, our study demonstrated that lncRNA SNHG5 can regulate the proliferation and metastasis of OS cells through the miR-212-3p/SGK3 axis. This axis may provide a new target for future clinical treatment.

Electronic supplementary material

The online version of this article (10.1186/s12935-018-0641-9) contains supplementary material, which is available to authorized users.

MicroRNA Expression Levels Are Altered in the Cerebrospinal Fluid of Patients with Young-Onset Alzheimer's Disease

Clinical diagnosis of Alzheimer’s disease (AD) prior to the age of 65 years is classified as young-onset (YOAD), whereas diagnosis after the age of 65 years is considered late-onset (LOAD). Although rare autosomal mutations more commonly associate with YOAD, most YOAD and LOAD cases are sporadic. YOAD and LOAD share amyloid and tau pathology, but many YOAD patients show increased disease severity and rate of progression. The current study examined the microRNA (miRNA) expression profile from exosomes isolated from the cerebrospinal fluid (CSF) of YOAD patients with biomarker-confirmed AD. Results uncovered miR-16-5p, miR-125b-5p, miR-451a, and miR-605-5p as differentially expressed in the CSF-derived exosomes of YOAD patients when compared with healthy controls (HC). In a cohort of LOAD patients, miR-125b-5p, miR-451a, and miR-605-5p were similarly altered in expression, but miR-16-5p showed similar expression to control. Analysis of the mRNA targets of these miRNAs revealed transcripts enriched in biological processes relevant to the post-mortem posterior cingulate cortex transcriptome in YOAD from a previously published microarray study, including those related to neuron projections, synaptic signaling, metabolism, apoptosis, and the immune system. Hence, these miRNAs represent novel targets for uncovering disease mechanisms and for biomarker development in both YOAD and LOAD.

Long non-coding RNA CASC2 inhibits tumorigenesis via the miR-181a/PLXNC1 axis in melanoma

Melanoma is the most malignant and aggressive form of skin carcinoma originating in the pigment-producing melanocytes. In this study, to further investigate the molecular mechanisms of the development and progression of melanoma, we explored the impacts of long non-coding RNA (lncRNA) CASC2 on melanoma cell functions. Microarray analysis was carried out to identify the expression of lncRNA CASC2 in melanoma cells. MiR-181a was predicted as a sponging target of CASC2 by miRcode, while the 3'-UTR of Plexin C1 (PLXNC1) was a potential target of miR-181a according to the TargetScan database. The correlation among CASC2, miR-181a, and PLXNC1 was verified by dual luciferase reporter assay and qRT-PCR. After manipulation of CASC2, miR-181a and PLXNC1 expression with transfection in A375 and M14 cells, cell viability, apoptosis, and invasive ability were evaluated using CCK-8, flow cytometry and Transwell assays, respectively. A low expression of CASC2 was detected in melanoma tissues and cells. Dual luciferase reporting assay confirmed that miR-181a targeted the 3'-UTR of PLXNC1. Furthermore, CASC2 could efficiently sponge miR-181a, thereby facilitating the expression of PLXNC1. Up-regulation of CASC2 suppressed the cell proliferation and invasion, but induced the apoptosis of melanoma cells. Our results demonstrated that lncRNA CASC2 can promote PLXNC1 expression by sponging miR-181a, thereby inhibiting the proliferation and invasion of melanoma cells, indicating that lncRNA CASC2 functions via the miR-181a/PLXNC1 axis in melanoma.