Long non-coding RNA SNHG6 enhances cell proliferation, migration and invasion by regulating miR-26a-5p/MAPK6 in breast cancer

ERK3 is involved in regulating cardiac fibroblast function

ERK3/MAPK6 activates MAP kinase-activated protein kinase (MK)-5 in selected cell types. Male MK5 haplodeficient mice show reduced hypertrophy and attenuated increase in Col1a1 mRNA in response to increased cardiac afterload. In addition, MK5 deficiency impairs cardiac fibroblast function. This study determined the effect of reduced ERK3 on cardiac hypertrophy following transverse aortic constriction (TAC) and fibroblast biology in male mice. Three weeks post-surgery, ERK3, but not ERK4 or p38α, co-immunoprecipitated with MK5 from both sham and TAC heart lysates. The increase in left ventricular mass and myocyte diameter was lower in TAC-ERK3+/- than TAC-ERK3+/+ hearts, whereas ERK3 haploinsufficiency did not alter systolic or diastolic function. Furthermore, the TAC-induced increase in Col1a1 mRNA abundance was diminished in ERK3+/- hearts. ERK3 immunoreactivity was detected in atrial and ventricular fibroblasts but not myocytes. In both quiescent fibroblasts and "activated" myofibroblasts isolated from adult mouse heart, siRNA-mediated knockdown of ERK3 reduced the TGF-β-induced increase in Col1a1 mRNA. In addition, intracellular type 1 collagen immunoreactivity was reduced following ERK3 depletion in quiescent fibroblasts but not myofibroblasts. Finally, knocking down ERK3 impaired motility in both atrial and ventricular myofibroblasts. These results suggest that ERK3 plays an important role in multiple aspects of cardiac fibroblast biology.

The Role of lncRNA-miR-26a-mRNA Network in Cancer Progression and Treatment

The role of non-coding RNAs in regulating biological processes associated with cancer progression, such as proliferation, migration, and apoptosis, has been extensively studied. Long non-coding RNAs (lncRNAs) play a role in regulating these processes through various mechanisms, including transcriptional and post-transcriptional modifications. In post-transcriptional regulation, lncRNAs can bind to specific miRNAs and affect their function, which can either promote or inhibit cancer development. The interaction between lncRNAs, miRNAs, and mRNAs forms a network known as competitive endogenous RNA (ceRNA), which is involved in cancer progression or inhibition. One specific miRNA called miR-26a-5p has been identified as having tumor-suppressive properties. However, when lncRNAs bind to and inhibit miR-26a-5p, it can lead to cancer progression. Therefore, targeting this ceRNA network could be a promising strategy for preventing cancer development. This review will first discuss the anticancer effects of miR-26a-5p and then explore the involvement of the lncRNA-miR26a-5p-mRNA axis in cancer progression and potential targeted therapies.

Expression of selected long non-coding RNAs in gastric cancer cells treated with coumarin: Possible mechanisms for anti-cancer activity

Long non-coding RNAs (lncRNAs) can be utilized as prognostic indicators of gastric cancer since they can affect several cancer-related processes. Coumarin is a natural product with some useful anti-cancer properties. Here, we measured the expression of selected lncRNAs (RuPAR, SNHG6, CASC11, and their targets, miR-340-5p, p21, E-cadherin, and CDK1) in AGS gastric cancer cells treated with coumarin. MTT test has been utilized for assessing the AGS cells' cell viability after exposure to coumarin. The expression of the lncRNAs (RuPAR, SNHG6, and CASC11) and miR-340-5p was evaluated via qRT-PCR. Western blot analysis has been utilized to determine changes in p21, E-cadherin, and CDK1 expression. Coumarin decreased AGS viability in a dose-dependent manner. The coumarin treated cells had lower levels of the mRNAs known to be targets of lncRNAs SNHG6 and CASC11 compared to control. Additionally, the coumarin group had increased levels of lncRNA RuPAR expression when compared with the control group. Some lncRNA targets, including p21, E-cadherin, and CDK1, showed lower expression in the coumarin group compared to the control by Western blotting. Coumarin could be a promising pharmacological candidate to be included in gastric cancer treatment regimens because it modulates lncRNAs and their targets.

LncRNA SNHG6 role in clinicopathological parameters in cancers

RNA sequencing has revealed that a substantial portion of the human genome undergoes transcription, yet a minimal fraction of these transcripts translates into proteins. LncRNAs, RNA molecules less than 200 nt in length, once deemed as transcriptional noise, have now emerged as crucial regulators of numerous cellular processes. This review focuses on the lncRNA SNHG6, aiming to elucidate its biogenesis, the pivotal roles it plays, and its mechanisms in facilitating the hallmarks of cancer. A comprehensive literature review and analysis were undertaken to delve into the biogenesis of SNHG6, its roles in cellular processes, and the mechanisms through which it contributes to the hallmarks of cancer. SNHG6 is a notable lncRNA, observed to be overexpressed in various cancer types; its perturbation has been linked to tumor progression, emphasizing its significance in oncogenesis. This lncRNA contributes to a range of cellular aberrations, influencing transcriptional, post-transcriptional, and epigenetic processes of mRNA, ultimately driving cancerous transformations. LncRNA SNHG6 serves as a potential biomarker and therapeutic target due to its association with tumorigenesis. Understanding its mechanism and role in cancer can pave the way for novel diagnostic and therapeutic strategies.

A comprehensive insight into the role of small nucleolar RNAs (snoRNAs) and SNHGs in human cancers

Long non-coding RNAs (lncRNAs), which comprise most non-coding RNAs (ncRNAs), have recently become a focus of cancer research. How many functional ncRNAs exist is still a matter of debate. Although insufficient evidence supports that most lncRNAs function as transcriptional by-products, it is widely known that an increasing number of lncRNAs play essential roles in cells. Small nucleolar RNAs (snoRNAs), 60-300 nucleotides in length, have been better studied than long non-coding RNAs (lncRNAs) and are predominantly present in the nucleolus. Most snoRNAs are encoded in introns of protein- and non-protein-coding genes called small nucleolar RNA host genes (SNHGs). In this article, we explore the biology and characteristics of SNHGs and their role in developing human malignancies. In addition, we provide an update on the ability of these snoRNAs to serve as prognostic and diagnostic variables in various forms of cancer.

The potential role of miRNAs in the pathogenesis of gallbladder cancer - A focus on signaling pathways interplay

microRNAs (also known as miRNAs or miRs) are a class of small non-coding RNAs that play a critical role in post-transcriptional gene regulation as negative gene regulators by binding complementary sequences in the 3'-UTR of target messenger RNAs (mRNAs) leading to translational repression and/or target degradation a wide range of genes and biological processes, including cell proliferation, invasion, migration, and apoptosis. The development and progression of cancer have been linked to the anomalous expression of miRNAs. According to recent studies, miRNAs have been found to regulate the expression of cancer-related genes through multiple signaling pathways in gallbladder cancer (GBC). Besides, miRNAs are implicated in several modulatory signaling pathways of GBC, including the Notch signaling pathway, JAK/STAT signaling pathway, protein kinase B (AKT), and Hedgehog signaling pathway. This review summarizes our current knowledge of the functions of miRNAs in the mechanisms underlying the pathogenic symptoms of GBC and illustrates their potential significance as treatment targets.

Long noncoding RNA SNHG6 promotes the malignant phenotypes of ovarian cancer cells via miR-543/YAP1 pathway

The long non-coding RNA small nucleolar RNA host gene 6 (SNHG6) acts as an oncogene in several cancers, and is highly expressed in ovarian cancer. MiR-543, a tumor suppressor, was expressed lowly in ovarian cancer. However, whether SNHG6 performed its oncogenic role via miR-543 in ovarian cancer, as well as the underlying mechanism is still not clear. In this study, we showed that the levels of SNHG6 and Yes-associated protein 1 (YAP1) were significantly elevated, while the level of miR-543 was significantly decreased, in ovarian cancer tissues compared with adjacent normal samples. We demonstrated that overexpression of SNHG6 significantly promoted the proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of ovarian cancer cells SKOV3 and A2780. Knockdown of SNHG6 showed the opposite effects. MiR-543 level was negatively correlated with the SNHG6 level in ovarian cancer tissues. SHNG6 overexpression significantly inhibited the expression of miR-543, and SHNG6 knockdown significantly elevated the expression of miR-543 in ovarian cancer cells. The effects of SNHG6 on ovarian cancer cells were abrogated by miR-543 mimic, and strengthened by anti-miR-543. YAP1 was identified as a target of miR-543. Forced expression of miR-543 significantly inhibited the expression of YAP1. Moreover, YAP1 overexpression could reverse the effects of SNHG6 downregulation on the malignant phenotypes of ovarian cancer cells. In summary, our study showed that SNHG6 promoted the malignant phenotypes of ovarian cancer cells via miR-543/YAP1 pathway.

CircDNAJC11 interacts with TAF15 to promote breast cancer progression via enhancing MAPK6 expression and activating the MAPK signaling pathway

BACKGROUND

Breast cancer (BC) is a common malignant tumor in women worldwide. Circular RNA (circRNA) has been proven to play a critical role in BC progression. However, the exact biological functions and underlying mechanisms of circRNAs in BC remain largely unknown.

METHODS

Here, we first screened for differentially expressed circRNAs in 4 pairs of BC tissues and adjacent non-tumor tissues using a circRNA microarray. Functionally, gain- and loss-of-function experiments in vitro and in vivo showed that circDNAJC11 promoted BC cell proliferation, migration, invasion, and tumor growth. Mechanistically, RNA pull-down, mass spectrum, RNA immunoprecipitation, fluorescence in situ hybridization assays, and rescue experiments were executed.

RESULTS

We found that circDNAJC11 was significantly upregulated in triple-negative breast cancer tissues and cells. Clinical data revealed that the high expression of circDNAJC11 was closely correlated with a poor prognosis of BC patients and could be an independent risk factor for BC prognosis. Functionally, gain- and loss-of-function experiments in vitro and in vivo showed that circDNAJC11 promoted BC cell proliferation, migration, invasion, and tumor growth. Mechanistically, RNA pull-down, mass spectrum, RNA immunoprecipitation, fluorescence in situ hybridization assays, and rescue experiments were executed. We demonstrated that circDNAJC11 combined with TAF15 to promote BC progression via stabilizing MAPK6 mRNA and activating the MAPK signaling pathway.

CONCLUSIONS

The circDNAJC11/TAF15/MAPK6 axis played a crucial role in the progression and development of BC, suggesting that circDNAJC11 might be a novel biomarker and therapeutical target for BC.

LncRNA SNHG6 Upregulates KPNA5 to Overcome Gemcitabine Resistance in Pancreatic Cancer via Sponging miR-944

Gemcitabine (GEM) is the gold-standard therapeutic regimen for patients with pancreatic cancer (PC); however, patients may receive limited benefits due to the drug resistance of GEM. LncRNA SNHG6 is reported to play key roles in drug resistance, but its role and molecular mechanism in PC remain incompletely understood. We found that LncRNA SNHG6 is drastically downregulated in GEM-resistant PC and is positively correlated with the survival of PC patients. With the help of bioinformatic analysis and molecular approaches, we show that LncRNA SNHG6 can sponge miR-944, therefore causing the upregulation of the target gene KPNA5. In vitro experiments showed that LncRNA SNHG6 and KPNA5 suppress PC cell proliferation and colony formation. The Upregulation of LncRNA SNHG6 and KPNA5 increases the response of GEM-resistant PANC-1 cells to GEM. We also show that the expression of KPNA5 is higher in patients without GEM resistance than in those who developed GEM resistance. In summary, our findings indicate that the LncRNA SNHG6/miR944/KPNA5 axis plays a pivotal role in overcoming GEM resistance, and targeting this axis may contribute to an increasing of the benefits of PC patients from GEM treatment.

Coding roles of long non-coding RNAs in breast cancer: Emerging molecular diagnostic biomarkers and potential therapeutic targets with special reference to chemotherapy resistance

Dysregulation of epigenetic mechanisms have been depicted in several pathological consequence such as cancer. Different modes of epigenetic regulation (DNA methylation (hypomethylation or hypermethylation of promotor), histone modifications, abnormal expression of microRNAs (miRNAs), long non-coding RNAs, and small nucleolar RNAs), are discovered. Particularly, lncRNAs are known to exert pivot roles in different types of cancer including breast cancer. LncRNAs with oncogenic and tumour suppressive potential are reported. Differentially expressed lncRNAs contribute a remarkable role in the development of primary and acquired resistance for radiotherapy, endocrine therapy, immunotherapy, and targeted therapy. A wide range of molecular subtype specific lncRNAs have been assessed in breast cancer research. A number of studies have also shown that lncRNAs may be clinically used as non-invasive diagnostic biomarkers for early detection of breast cancer. Such molecular biomarkers have also been found in cancer stem cells of breast tumours. The objectives of the present review are to summarize the important roles of oncogenic and tumour suppressive lncRNAs for the early diagnosis of breast cancer, metastatic potential, and chemotherapy resistance across the molecular subtypes.

Silencing lncRNA Snhg6 mitigates bleomycin-induced pulmonary fibrosis in mice via miR-26a-5p/TGF-β1-smads axis

Idiopathic pulmonary fibrosis (IPF) is an interstitial pulmonary disease with slow onset and high mortality. Epithelial-mesenchymal transition (EMT) is a significant condition for tissue fibrosis, and lncRNA-Snhg6 (small nucleolar RNA host gene 6) is related to EMT in some cancer cells, but its role in pulmonary fibrosis remains obscure. Here, we found that TGF-β1 and Snhg6 were up-regulated in lung tissues of BLM-induced lung fibrosis mouse, and Snhg6 expression was significantly increased in primary lung fibroblasts after BLM treatment. Snhg6 knockdown notably alleviated the pulmonary dysfunction, and the increase of fibrosis area and collagen deposition induced by BLM. MiR-26a-5p was downregulated in BLM-induced fibrotic lung tissues, and it was negatively regulated by Snhg6. Silencing Snhg6 markedly alleviated the TGF-β1-induced increase in fibrotic marker expression, cell proliferation, migration and differentiation, as well as the nuclear transport of p-Smad2/3 by modulating miR-26a-5p expression in mouse lung fibroblasts. Moreover, overexpressing Snhg6-induced collagen accumulation and fibroblast activation in fibroblasts, which was reversed by treatment with miR-26a-5p mimic or oxymatrine (an inhibitor of TGF-β1-Smads pathway). Interestingly, silencing Snhg6 in vivo mitigated BLM-driven pulmonary fibrosis by regulating the miR-26a-5p/TGF-β1-Smads axis. Our data revealed that Snhg6 contributed to the process of BLM-driven lung fibrosis in mouse by modulating the miR-26a-5p/TGF-β1-Smads axis, suggesting that Snhg6 might be a therapeutic target for lung fibrosis.

LncRNA LINC00665 Promotes Ovarian Cancer Cell Proliferation and Inhibits Apoptosis via Targeting miR-181a-5p/FHDC

Previous reports indicate that long intergenic non-coding RNA LINC00665 naturally occurred vital effects in various cancers. Herein, the role of LINC00665 in ovarian cancer progress was explored. We found that LINC00665 was upregulated in ovarian cancer cell lines. Besides, a series of assays including flow cytometry, wound-healing, transwell, cell counting Kit-8 (CCK-8), and EdU assay confirmed that the knockdown of LINC00665 could reduce the viability, proliferation, and migration of SKOV-3 and OVCAR-3 cells. Accumulating evidence indicates that many lncRNAs can function as endogenous miRNA sponges by competitively binding common miRNAs. In this study, the bioinformatics analysis suggests that LNC00665 specifically binds to miR-181a-5p. LINC00665 downregulated the miR-181a-5p in SKOV-3 and OVCAR-3 cells. The knockdown of miR-181a-5p evidently reverses the inhibitory effect of sh-LINC00662. Besides, FH2 domain containing 1 (FHDC1) has been proved to deed as an effective target of miR-181a-5p. The results reveal the knockdown of LINC00665 facilitates ovarian cancer via development by sponging miR-181a-5p and up-regulating FHDC1 expression. These may contribute to ovarian cancer therapy.

Vitamin D May Protect against Breast Cancer through the Regulation of Long Noncoding RNAs by VDR Signaling

Dietary vitamin D3 has attracted wide interest as a natural compound for breast cancer prevention and therapy, supported by in vitro and animal studies. The exact mechanism of such action of vitamin D3 is unknown and may include several independent or partly dependent pathways. The active metabolite of vitamin D3, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D, calcitriol), binds to the vitamin D receptor (VDR) and induces its translocation to the nucleus, where it transactivates a myriad of genes. Vitamin D3 is involved in the maintenance of a normal epigenetic profile whose disturbance may contribute to breast cancer. In general, the protective effect of vitamin D3 against breast cancer is underlined by inhibition of proliferation and migration, stimulation of differentiation and apoptosis, and inhibition of epithelial/mesenchymal transition in breast cells. Vitamin D3 may also inhibit the transformation of normal mammary progenitors into breast cancer stem cells that initiate and sustain the growth of breast tumors. As long noncoding RNAs (lncRNAs) play an important role in breast cancer pathogenesis, and the specific mechanisms underlying this role are poorly understood, we provided several arguments that vitamin D3/VDR may induce protective effects in breast cancer through modulation of lncRNAs that are important for breast cancer pathogenesis. The main lncRNAs candidates to mediate the protective effect of vitamin D3 in breast cancer are lncBCAS1-4_1, AFAP1 antisense RNA 1 (AFAP1-AS1), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), long intergenic non-protein-coding RNA 511 (LINC00511), LINC00346, small nucleolar RNA host gene 6 (SNHG6), and SNHG16, but there is a rationale to explore several other lncRNAs.

Aberrant expression of lncRNAs SNHG6, TRPM2-AS1, MIR4435-2HG, and hypomethylation of TRPM2-AS1 promoter in colorectal cancer

Accumulating evidence has indicated that deregulation of lncRNAs plays essential roles in colorectal cancer (CRC) carcinogenesis. The goal of this study was to analyze the expression of lncRNAs in colorectal cancer and their association with clinicopathological variables. Bioinformatics analysis of published CRC microarray data was performed to identify the important lncRNAs. The expression levels of candidate genes were assessed in the human colon cancer/normal cell lines, CRC, adenomatous colorectal polyps, and their marginal tissues by qRT-PCR. Moreover, the methylation status of the TRPM2-AS1 promoter was studied using qMSP assay. Furthermore, we investigated the molecular mechanisms of these lncRNAs in CRC progression using in silico analysis. Microarray analysis revealed that lncRNAs SNHG6, MIR4435-2HG, and TRPM2-AS1 were upregulated in CRC. These results were validated in colon cell lines. Moreover, qRT-PCR showed that the expression levels of SNHG6 and TRPM2-AS1 were upregulated in the colorectal tumor tissues compared with their paired tissues. Nonetheless, there was no significant increase in MIR4435-2HG expression in CRC samples. Furthermore, we observed a significant hypomethylation of TRPM2-AS1 promoter and its activation in CRC tissues. By in silico analysis, we found that the lncRNAs upregulation could promote proliferation and drug resistance of colorectal cancer cells via miRNAs sponging and modulation of their targets expression. In conclusion, based on our results upregulation of SNHG6 and TRPM2-AS1, and hypomethylation of TRPM2-AS1 promoter might be considered as potential diagnostic biomarkers for CRC initiation and development.

Long non-coding RNA VCAN-AS1 promotes the malignant behaviors of breast cancer by regulating the miR-106a-5p-mediated STAT3/HIF-1α pathway

An accumulating number of studies have found that long noncoding RNAs (lncRNAs) participate in breast cancer (BC) development. LncRNA VCAN-AS1, a novel lncRNA, has been confirmed to regulate the progression of gastric cancer, while its role in BC is elusive. Here, our results illustrate that VCAN-AS1 is overexpressed in BC tissues and cells, while miR-106a-5p was downregulated and negatively correlated with VCAN-AS1. In addition, high VCAN-AS1 expression and low miR-106a-5p expression were closely correlated with poor overall survival in BC patients. Functional experiments confirmed that VCAN-AS1 overexpression notably accelerated BC cell proliferation, migration, invasion, and epithelial–mesenchymal transition (EMT) and enhanced tumor cell growth while also suppressing cell apoptosis. However, overexpression of miR-106a-5p had the opposite effects. In addition, rescue experiments confirmed that overexpression of VCAN-AS1 inhibited the tumor-suppressive effects mediated by miR-106a-5p. Mechanistically, through bioinformatics analysis, we found that VCAN-AS1 functions as a competitive endogenous RNA (ceRNA) of miR-106a-5p, which targets the 3ʹ untranslated region (UTR) of signal transducer and activator of transcription 3 (STAT3). Further experiments indicated that miR-106a-5p downregulated the STAT3/hypoxia-inducible factor-1alpha (HIF-1α) pathway, while activating the STAT3 pathway reversed miR-106a-5p-mediated antitumor effects. Collectively, our data suggest that VCAN-AS1 is upregulated in breast cancer and promotes its progression by regulating the miR-106a-5p-mediated STAT3/HIF-1α pathway. This study provides a new target for BC therapy.

lncRNAs as Potential Targets in Small Cell Lung Cancer: MYC -dependent Regulation

BACKGROUND

Small Cell Lung Cancer (SCLC) is a highly aggressive malignancy. MYC family oncogenes are amplified and overexpressed in 20% of SCLCs, showing that MYC oncogenes and MYC regulated genes are strong candidates as therapeutic targets for SCLC. c-MYC plays a fundamental role in cancer stem cell properties and malignant transformation. Several targets have been identified by the activation/repression of MYC. Deregulated expression levels of lncRNAs have also been observed in many cancers.

OBJECTIVE

The aim of the present study is to investigate the lncRNA profiles which depend on MYC expression levels in SCLC.

METHODS

Firstly, we constructed lentiviral vectors for MYC overexpression/inhibition. MYC expression is suppressed by lentiviral shRNA vector in MYC amplified H82 and N417 cells, and overexpressed by lentiviral inducible overexpression vector in MYC non-amplified H345 cells. LncRNA cDNA is transcribed from total RNA samples, and 91 lncRNAs are evaluated by qRT-PCR.

RESULTS

We observed that N417, H82 and H345 cells require MYC for their growth. Besides, MYC is not only found to regulate the expressions of genes related to invasion, stem cell properties, apoptosis and cell cycle (p21, Bcl2, cyclinD1, Sox2, Aldh1a1, and N-Cadherin), but also found to regulate lncRNAs. With this respect, expressions of AK23948, ANRIL, E2F4AS, GAS5, MEG3, H19, L1PA16, SFMBT2, ZEB2NAT, HOTAIR, Sox2OT, PVT1, and BC200 were observed to be in parallel with MYC expression, whereas expressions of Malat1, PTENP1, Neat1, UCA1, SNHG3, and SNHG6 were inversely correlated.

CONCLUSION

Targeting MYC-regulated genes as a therapeutic strategy can be important for SCLC therapy. This study indicated the importance of identifying MYC-regulated lncRNAs and that these can be utilized to develop a therapeutic strategy for SCLC.

Angiogenesis-related non-coding RNAs and gastrointestinal cancer

Gastrointestinal (GI) cancers are among the main reasons for cancer death globally. The deadliest types of GI cancer include colon, stomach, and liver cancers. Multiple lines of evidence have shown that angiogenesis has a key role in the growth and metastasis of all GI tumors. Abnormal angiogenesis also has a critical role in many non-malignant diseases. Therefore, angiogenesis is considered to be an important target for improved cancer treatment. Despite much research, the mechanisms governing angiogenesis are not completely understood. Recently, it has been shown that angiogenesis-related non-coding RNAs (ncRNAs) could affect the development of angiogenesis in cancer cells and tumors. The broad family of ncRNAs, which include long non-coding RNAs, microRNAs, and circular RNAs, are related to the development, promotion, and metastasis of GI cancers, especially in angiogenesis. This review discusses the role of ncRNAs in mediating angiogenesis in various types of GI cancers and looks forward to the introduction of mimetics and antagonists as possible therapeutic agents.

LncRNA SNHG6/miR-125b-5p/BMPR1B Axis: A New Therapeutic Target for Triple-Negative Breast Cancer

Background

Triple-negative breast cancer (TNBC) is a significant cause of patient morbidity. The exactly pathobiological features of this condition has yet to be completely elucidated.

Methods

Breast cancer data obtained from The Cancer Genome Atlas (TCGA) database were evaluated for lncRNA SNHG6 expression. Normal human breast epithelial cell line (MCF-10A) and other breast cancer cell lines (BT-549, MDA-MB-231, Hs 578t, ZR-75-30, SK-BR-3, MCF-7) were also assessed for lncRNA SNHG6 expressions. Cellular proliferative ability was evaluated with colony formation and CCK-8 assays. The ability of cells to migrate was scrutinized with the wound healing and Boyden chamber cell migration assays. qRT-PCR enabled for detection of lncRNA SNHG6, miR-125b-5p and BMPR1B mRNA expressions. Protein BMPR1B expressions were further assessed using Western Blotting. Direct binding sites between transcripts were determined using dual-luciferase reporter assays. We also constructed a xenograft mouse model to further dissect the vivo implications of lncRNA SNHG6. Ki-67 and c-Caspase-3 expressions were detected using immunohistochemistry staining.

Results

Breast cancer cell lines demonstrated higher lncRNA SNHG6 expressions, particularly TNBC cell lines, in contrast to normal breast epithelial cell lines. This finding coincided with those noted on analysis of TCGA breast cancer data. lncRNA SNHG6 knockdown inhibited TNBC cell proliferation, migration, while promoted cell apoptosis. Furthermore, suppressed lncRNA SNHG6 expressions resulted in lower tumor weights and volumes in a xenograft mouse model, as evidenced by Ki-67 and c-Caspase-3 expression profiles in tumor tissues. miR-125b-5p and lncRNA SNHG6/BMPR1B both possessed direct binding sites for each other which was validated utilizing a dual-luciferase reporter assay. Decreasing lncRNA SNHG6 expression in TNBC cells upregulated miR-125b-5p expression. Another side, inhibiting miR-125b-5p upregulated BMPR1B expression in these cells. Moreover, knocking down lncRNA SNHG6 downregulated BMPR1B expression in TNBC cells, and the finding was rescued in cells which were exposed to miR-125b-5p inhibitor. Downregulating miR-125b-5p mitigated the effect of suppressing lncRNA SNHG6 on TNBC cell proliferation, migration, and apoptosis.

Conclusion

Downregulation of lncRNA SNHG6 could inhibit TNBC cell proliferative, migratory capabilities and promote apoptosis capability, likely through modulation of the miR-125b-5p/BMPR1B axis. This axis may be targeted in formulating new therapies for TNBC.

miR‑653‑5p suppresses the growth and migration of breast cancer cells by targeting MAPK6

Breast cancer is the worldwide leading cause of cancer‑related deaths among women. Increasing evidence has demonstrated that microRNAs (miRNAs) play critical roles in the carcinogenesis and progression of breast cancer. miR‑653‑5p was previously reported to be involved in cell proliferation and apoptosis. However, the role of miR‑653‑5p in the progression of breast cancer has not been studied. In the present study, it was found that overexpression of miR‑653‑5p significantly inhibited the proliferation, migration and invasion of breast cancer cells in vitro. Moreover, overexpression of miR‑653‑5p promoted cell apoptosis in breast cancer by regulating the Bcl‑2/Bax axis and caspase‑9 activation. Additionally, the epithelial‑mesenchymal transition and activation of the Akt/mammalian target of rapamycin signaling pathway were also inhibited by miR‑653‑5p. Furthermore, the data demonstrated that miR‑653‑5p directly targeted mitogen‑activated protein kinase 6 (MAPK6) and negatively regulated its expression in breast cancer cells. Upregulation of MAPK6 could overcome the inhibitory effects of miR‑653‑5p on cell proliferation and migration in breast cancer. In conclusion, this study suggested that miR‑653‑5p functions as a tumor suppressor by targeting MAPK6 in the progression of breast cancer, and it may be a potential target for breast cancer therapy.

Small nucleolar RNA and its potential role in breast cancer - A comprehensive review

Small Nucleolar RNAs (snoRNAs) are known for their canonical functions, including ribosome biogenesis and RNA modification. snoRNAs act as endogenous sponges that regulate miRNA expression. Thus, precise snoRNA expression is critical for fine-tuning miRNA expression. snoRNAs processed into miRNA-like sequences play a crucial role in regulating the expression of protein-coding genes similar to that of miRNAs. Recent studies have linked snoRNA deregulation to breast cancer (BC). Inappropriate snoRNA expression contributes to BC pathology by facilitating breast cells to acquire cancer hallmarks. Since snoRNAs show significant differential expression in normal and cancer conditions, measuring snoRNA levels could be useful for BC prognosis and diagnosis. The present article provides a comprehensive overview of the role of snoRNAs in breast cancer pathology. More specifically, we have discussed the regulation, biological function, signaling pathways, and clinical utility of abnormally expressed snoRNAs in BC. Besides, we have also discussed the role of snoRNA host genes in breast tumorigenesis and emerging and future research directions in the field of snoRNA and cancer.

A competing endogenous RNA network reveals key lncRNAs associated with sepsis

BACKGROUND

This study set out to determine key lncRNAs correlated with sepsis via constructing competing endogenous RNA (ceRNA) network.

METHODS

Three septic patients and three healthy controls were recruited to obtain lncRNA profiles in this current study. Combined with the mRNA profiles by RNA-sequencing, an integrated analysis of mRNA expression profiles downloaded from GEO was performed to obtain the differentially expressed mRNAs (DEmRNAs). Based on differentially expressed lncRNAs (DElncRNAs) and DEmRNAs acquired in this present study and differentially expressed miRNAs (DEmiRNAs) acquired in previous study, a ceRNA network was constructed. Furthermore, LINC00963 was validated in THP-1 cells by performing loss of function assays.

RESULTS

In this analysis, a total of 290 DEmRNAs and 46 DElncRNAs were detected in sepsis. Parkinson's disease, Oxidative phosphorylation and Cardiac muscle contraction were significantly enriched KEGG pathways in sepsis. XPO1, CUL4A, and NEDD8 were three hub proteins of sepsis-specific PPI network. A ceRNA network, which contained 16 DElncRNA-DEmiRNA pairs and 82 DEmiRNA-DEmRNA pairs, involving 5 lncRNAs, 10 miRNAs, and 60 mRNAs, was obtained. The function experiments indicated that knockdown of LINC00963 could promote cell proliferation, reduce cytokine expression, and suppress inflammasome activation and phagocytosis in LPS-induced THP-1 cells.

CONCLUSION

This study determined key lncRNAs involved in sepsis, which may contribute to the development for novel treatment strategy of sepsis.

Long Noncoding RNA LINC02163 Accelerates Malignant Tumor Behaviors in Breast Cancer by Regulating the MicroRNA-511-3p/HMGA2 Axis

Long intergenic nonprotein-coding RNA 02163 (LINC02163) has been reported to be upregulated and work as an oncogene in gastric cancer. The aims of the present study were to determine the expression profile and clinical value of LINC02163 in breast cancer. Additionally, the detailed functions of LINC02163 in breast cancer were explored, and relevant molecular events were elucidated. In this study, LINC02163 was upregulated in breast cancer, and its expression level was closely associated with tumor size, lymph node metastasis, and TNM stage. Patients with breast cancer presenting high LINC02163 expression exhibited shorter overall survival than those presenting low LINC02163 expression. Knockdown of LINC02163 resulted in a decrease in breast cancer cell proliferation, migration, and invasion and an increase in cell apoptosis in vitro. In addition, silencing of LINC02163 impeded breast cancer tumor growth in vivo. Mechanistic investigation revealed that LINC02163 served as a competing endogenous RNA for microRNA-511-3p (miR-511-3p) and consequently upregulated the expression of the high-mobility group A2 (HMGA2), a downstream target of miR-511-3p. Intriguingly, miR-511-3p inhibition and HMGA2 restoration counteracted the effects of LINC02163 deficiency on the malignant properties of breast cancer cells. LINC02163 exerts cancer-promoting effects during the initiation and progression of breast cancer via regulation of the miR-511-3p/HMGA2 axis. Our findings add to our understanding of the roles of the LINC02163/miR-511-3p/HMGA2 pathway as a regulator of breast cancer pathogenesis and may be useful in the development of lncRNA-directed cancer diagnosis, prognosis, and therapy.

let7f‑5p attenuates inflammatory injury in in vitro pneumonia models by targeting MAPK6

Pneumonia accounts for ~1.3 million mortalities in children per year worldwide. MicroRNAs are implicated in several diseases, including cancer and pneumonia; however, the role of let7f-5p in pneumonia is not completely understood. In the present study, lipopolysaccharide (LPS) was used to establish an in vitro pneumonia model in A549 and WI-38 cells. The reverse transcription-quantitative PCR (RT-qPCR) and western blotting results demonstrated that let7f-5p expression levels were significantly decreased, whereas MAPK6 expression levels were significantly increased in the peripheral venous blood of patients with pneumonia and in LPS-induced A549 and WI-38 cells compared with healthy volunteers and control cells, respectively. Furthermore, the dual-luciferase reporter assay demonstrated that let7f-5p targeted the 3′-untranslated region of MAPK6. The ELISA and RT-qPCR results demonstrated that let7f-5p mimic ameliorated LPS-induced inflammatory injury in A549 and WI-38 cells, as demonstrated by decreased expression levels of proinflammatory cytokines, including TNF-α and IL-6. In addition, the Cell Counting Kit-8 assay results indicated that let7f-5p mimic ameliorated LPS-induced reductions in cell viability, and the western blotting results demonstrated that let7f-5p mimic reversed LPS-induced activation of the STAT3 signaling pathway. Notably, the aforementioned let7f-5p-mediated effects were reversed by MAPK6 overexpression. Collectively, the results of the present study suggested that let7f-5p inhibited inflammation by targeting MAPK6 in the in vitro pneumonia model, thus let7f-5p may serve as a potential novel therapeutic target for pneumonia.

Long non-coding RNA LSINCT5 inactivates Wnt/β-catenin pathway to regulate MCF-7 cell proliferation and motility through targeting the miR-30a

Background

Breast cancer (BC) is the most common malignant tumor among women. Earlier studies showed that long stress-induced non-coding transcript 5 (LSINCT5) was implicated in BC. However, the potential mechanisms of LSINCT5 in BC is still elusive.

Methods

Relative expression of LSINCT5 in BC tissues and cells were quantified by quantitative real-time reverse transcription PCR (qRT-PCR). shRNA was employed to specifically knockdown endogenous LSINCT5 in BC cells. Cell growth and invasion activity of BC cells was assessed by colony formation and transwell migration assay, respectively. The association between LSINCT5 and miR-30a was conducted by luciferase reporter assay. Subcutaneous injection of sh-LSINCT5 transfected MCF-7 cells into the ventral regions of mice to form tumors. Mice were divided into three groups (n=10): control group, sh-NC group, sh-LSINCT5 group (sh-NC or sh-LSINCT5 transfected MCF-7 cells injected into mice). Tumor weight was checked after 30 days post-injection.

Results

LSINCT5 was significantly up-regulated in BC tissues and cells. LSINCT5 knockdown suppressed proliferation, invasion, and epithelial-mesenchymal transition (EMT) in vitro and in vivo. LSINCT5 acted as a sponge molecule and targeted miR-30a in BC cells. Further mechanistic study exhibited that overexpression of LSINCT5 promoted the expression of Wnt/β-catenin-related proteins (β-catenin, TCF4, and c-Myc). In vivo, xenograft nude mice experiment indicated sh-LSINCT5 inhibited tumor growth and motility by targeting miR-30a through modulating Wnt/β-catenin pathway.

Conclusions

The present results uncovered that LSINCT5 knockdown suppressed BC growth and metastasis via the miR-30a/Wnt/β-catenin axis, and it served as a potential therapeutic target for early diagnosis and treatment of BC patients..

The comparison of miRNAs that respond to anti-breast cancer drugs and usnic acid for the treatment of breast cancer

This study was designed to compare usnic acid with anti-breast cancer drug molecules (A-BCDM) routinely used in the treatment of breast cancer. The miRNA information of 17 anti-breast cancer drug used in breast cancer treatment was obtained from the Small Molecule-miRNA Network-Based Inferance (SMIR-NBI) tool. We had been determined common and different expressed miRNAs between 17 A-BCDM & usnic acid and were classified according to the common miRNAs to reveal molecular similarity. As a result of the bioinformatic analyzes, 20 common miRNAs were determined between 17 A-BCDM and usnic acid. The common miRNAs were analyzed with bioinformatic tolls for determining pathways and targets. The most common miRNAs for 6 of 17 A-BCDM and usnic acid were determined as miR-374a-5p and miR-26a-5p. We compared the anti-proliferative effect of usnic acid and one of the 17 A-BCDM that tamoxifen on MDA-MB-231 triple negative breast cancer cell with real-time cell analysis system. The real time PCR assay was carried out with miR-26a-5p for evaluate to expression level of MDA-MB-231 breast cancer cell and MCF-12A non-cancerous epithelial breast cell. As a result of study, usnic acid as novel candidate drug molecule showed high similarity ratio with 5-Fluorouracil, Sulindac Sulfide, Curcumin and Cisplatin A-BCDM used in treatment of breast cancer. miR-26a-5p as common response miRNA of usnic acid and tamoxifen was showed a decreased level of expression by validated qRT-PCR assay. The obtained from study, in addition to 17 A-BCDM, usnic acid has also the potential to be used as a candidate molecule in the treatment of breast cancer. Moreover, miR-26a-5p might be used as a biomarker in the treatment of breast cancer but further analysis is required.

Silencing of Long Noncoding RNA SNHG6 Inhibits Esophageal Squamous Cell Carcinoma Progression via miR-186-5p/HIF1α Axis

AIMS

Long noncoding RNA (lncRNA) small nucleolar RNA host gene 6 (SNHG6) has been shown to be upregulated in esophageal squamous cell carcinoma (ESCC). However, its detailed function in ESCC remains unknown. We investigated its specific roles in ESCC cell proliferation, invasion, and migration.

METHODS

Gene expression was evaluated by quantitative reverse transcriptase polymerase chain reaction and western blot. The subcellular localization of lncRNA SNHG6 was determined using subcellular location assay. Luciferase reporter assay and RNA pull-down assay were applied to determine the interaction between lncRNA SNHG6, miR-186-5p, and hypoxia-inducible factor 1α (HIF1α). The cell proliferation, migration, and invasion abilities were evaluated by using cell count kit-8, colony formation assay, and transwell migration and invasion assays.

RESULTS

LncRNA SNHG6 and HIF1α were upregulated, while miR-186-5p was downregulated in ESCC tissues and cell lines. Knockdown of lncRNA SNHG6 inhibits ESCC cell proliferation, migration, and invasion. A negative correlation between lncRNA SNHG6 and miR-186-5p expression was found in ESCC tissues. Similarly, there is a positive correlation between lncRNA SNHG6 and HIF1α expression in ESCC tissues. Conversely, miR-186-5p expression was negatively correlated with HIF1α expression in ESCC tissues. Furthermore, lncRNA SNHG6 was identified as a decoy for miR-186-5p, thereby promoting the expression of miR-186-5p target HIF1α. More significantly, restoration of SNHG6 or HIF1α could reverse the inhibitory effect of miR-186-5p on ESCC cell proliferation, migration, and invasion.

CONCLUSIONS

Downregulation of SNHG6 inhibited the proliferation, migration, and invasion of ESCC cells through regulating miR-186-5p/HIF1α axis, providing a novel therapeutic target for ESCC.

Long non-coding RNA SNHG6 regulates the sensitivity of prostate cancer cells to paclitaxel by sponging miR-186

Background

Chemo-resistance is one of the main obstacles in the treatment of prostate cancer (PCa). Long non-coding RNA small nucleolar RNA host gene 6 (SNHG6) is involved in the chemo-resistance of various tumors. We aim to survey the role and underlying molecular mechanism of SNHG6 in PCa resistance to paclitaxel (PTX).

Methods

The expression of SNHG6 and miR-186 was detected using quantitative real time polymerase chain reaction (qRT-PCR). The proliferation, migration, invasion, and apoptosis of PTX-resistant PCa cells were determined via 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), transwell assay, or flow cytometry assay. Protein levels of CyclinD1, matrix metalloproteinase 9 (MMP9), Vimentin, E-cadherin, Cleaved-caspase-3 (Cleaved-casp-3) Cleaved-caspase-9 (Cleaved-casp-9), Multidrug Resistance associated Protein 1 (MRP1), and multidrug resistance-1 (MDR1) were assessed by western blot analysis. The relationship between SNHG6 and miR-186 were confirmed by dual-luciferase reporter assay. The role of SNHG6 in vivo was confirmed by xenograft tumor model.

Results

SNHG6 expression was increased and miR-186 expression was reduced in drug-resistant PCa tissues and cells. SNHG6 knockdown elevated PTX-resistant PCa cells sensitivity to PTX in vitro and in vivo, and repressed proliferation, migration, and invasion of PTX-resistant PCa cells in vitro. Importantly, SNHG6 acted as a sponge of miR-186. Furthermore, miR-186 downregulation reversed SNHG6 silencing-mediated cell sensitivity to PTX, proliferation, migration, and invasion in PTX-resistant PCa cells.

Conclusions

SNHG6 knockdown elevated the sensitivity of PTX-resistant PCa cells to PTX by sponging miR-186, indicating that SNHG6 might be a therapeutic target for PCa.

Long Non-Coding Small Nucleolar RNA Host Genes (SNHGs) in Endocrine-Related Cancers

Long non-coding RNAs (lncRNAs) are emerging regulators of a diverse range of biological processes through various mechanisms. Genome-wide association studies of tumor samples have identified several lncRNAs, which act as either oncogenes or tumor suppressors in various types of cancers. Small nucleolar RNAs (snoRNAs) are predominantly found in the nucleolus and function as guide RNAs for the processing of transcription. As the host genes of snoRNAs, lncRNA small nucleolar RNA host genes (SNHGs) have been shown to be abnormally expressed in multiple cancers and can participate in cell proliferation, tumor progression, metastasis, and chemoresistance. Here, we review the biological functions and emerging mechanisms of SNHGs involved in the development and progression of endocrine-related cancers including thyroid cancer, breast cancer, pancreatic cancer, ovarian cancer and prostate cancer.

The prognostic value of lncRNA SNHG6 in cancer patients

Background

Although tremendous improvement has been seen in cancer diagnosis and treatment, its morbidity and mortality is still high due to lack of ideal biomarkers. An increasing number of studies have demonstrated that the expression of lncRNA small nucleolar RNA host gene 6 (SNHG6) has significantly negative correlation with various cancer prognosis. The present meta-analysis was aimed to clarify the potential of clinical application of SNHG6 in cancers.

Methods

A detailed literature review was conducted by searching through PubMed and Web of Science databases. The expression level of SNHG6, clinicopathological features and survival outcomes were extracted from eligible studies. Pooled analysis was performed with a DerSimonian-Laird random-effect model. The results were further validated through the Cancer Genome Atlas (TCGA) dataset.

Results

Five studies with a total of 487 cases were finally included in this meta-analysis. The results demonstrated that a high expression of SNHG6 was significantly associated with an increased risk of poor overall survival (OS) in cancer patients (HR = 2.06, 95% CI 1.56–2.73). Similar results from the TCGA dataset further confirmed our findings.

Conclusions

Overexpressed SNHG6 was significantly associated with poor prognosis in various cancers. Therefore, SNHG6 may become a novel molecular target for treatment and prognostic evaluation.

The Regulatory Role of circRNA_101308 in Cervical Cancer and the Prediction of Its Mechanism

Purpose

Accumulating evidence indicates that circular RNAs (circRNAs) are closely involved in canceration and cancer progression. However, the role of circRNAs in cervical cancer (CC) is largely unknown. Here, we characterized the role of circRNA_101308 in CC.

Materials and Methods

The expression of circRNA_101308 in CC tissues was measured by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Then, circRNA_101308 was overexpressed in CC cells to detect its function by proliferation and apoptosis assays, Transwell assays and animal experiments. The potential mechanism of circRNA_101308 in CC was explored by RNA pull-down, Gene Ontology (GO) and pathway analyses.

Results

CircRNA_101308 was significantly downregulated in CC tissues. The level of circRNA_101308 was much lower in CC patients with lymph node metastasis or deep myometrial invasion compared to those patients without lymph node metastasis and superficial myometrial invasion. CircRNA_101308 overexpression inhibited CC cell proliferation, invasion and migration. MiR-26a-5p, miR-196a-5p, miR-196b-5p, miR-335-3p, and miR-1307-3p were found to be sponged by circRNA_101308 in CC cells. Further, GO and pathway analyses predicted the potential functional processes and pathways of circRNA_101308 in CC.

Conclusion

CircRNA_101308 is downregulated and acts as a tumor suppressor in CC. CircRNA_101308 can participate in many different processes by sponging different miRNAs in CC cells. This exploration of circRNA_101308 provides new directions for research on cancer development and the clinical treatment of CC.

Long noncoding RNA SNHG6 mainly functions as a competing endogenous RNA in human tumors

Increased expression of the small nucleolar RNA host gene 6 (SNHG6) has been reported in different cancers, such as hepatocellular carcinoma, colorectal cancer, and lung cancer. The high expression level of SNHG6 is associated with tumor progression and poor prognosis. This paper provides an overview of recent studies on the oncogenic role and potential clinical utilities of SNHG6. Upregulated SNHG6 arrests tumor cell cycle and reduces apoptosis but promotes migration, invasion, metastasis, epithelial-mesenchymal transition (EMT), and chemoresistance in tumors. Mechanically, SNHG6 primarily sponges tumor suppressor microRNA (miRNA), functioning as a competing endogenous RNA. Once sponged, miRNA is unable to degrade, silence, or hamper the translation of its downstream, mostly oncogenic genes, ultimately driving cancer-related processes. Thus, SNHG6 might serve as a biomarker for cancer diagnosis and prognosis.

LncRNA MCM3AP-AS1 promotes breast cancer progression via modulating miR-28-5p/CENPF axis

Breast cancer is one of the commonly occurred cancers among women and poses a huge threat against female health. Abnormal expression of lncRNA has been confirmed to be an important inducer of cancer. By searching GEO and TCGA database, we found that CENPF was upregulated in breast cancer tissues. Through RT-qPCR, CENPF was found to be upregulated in breast cancer cells. Functional experiments revealed that CENPF had positive effect on the cellular functions, including proliferation, migration and invasion. Subsequently, CENPF was confirmed to combine with miR-28-5p, and its expression was suppressed by miR-28-5p. Furthermore, it was found that miR-28-5p bound to MCM3AP-AS1, and MCM3AP-AS1 expressed at a high level in breast cancer cells. Besides, MCM3AP-AS1 was confirmed as a cytoplasmic RNA. In addition, there was a positive expression correlation between MCM3AP-AS1 and CENPF. Therefore, MCM3AP-AS1 was confirmed to regulate CENPF via competitively binding to miR-28-5p. At last, rescue assays demonstrated that knockdown of CENPF restored miR-28-5p repression-induced cellular processes in MCM3AP-AS1-silenced cells. In vivo assay revealed that MCM3AP-AS1 could hasten tumor growth in breast cancer by targeting CENPF. All results indicated that MCM3AP-AS1/miR-28-5p/CENPF axis accelerates breast cancer progression.

LncRNA SNHG17 aggravated prostate cancer progression through regulating its homolog SNORA71B via a positive feedback loop

Prostate cancer (PC) is a prevalent male malignancy with high occurrence rate. Recent studies have showed that small nucleolar host genes (SNHGs) and their homolog small nucleolar RNAs (snoRNAs) elicit regulatory functions in carcinogenesis. Present study aimed to investigate the role of SNHG17 and its homolog SNORA71B in PC. Function of SNHG17 and SNORA71B in PC is detected by CCK-8, colony formation, flow cytometry analysis of apoptosis, and transwell migration assay. The mechanism whereby SNHG17 regulated SNORA71B was detected by RIP, pulldown, ChIP, and luciferase reporter assays. Results depicted that transcript 6 of SNHG17 and SNORA71B were upregulated in PC. Knockdown of SNHG17 or SNORA71B weakened proliferation, invasion, migration, and epithelial-to-mesenchymal transition (EMT) and strengthened apoptosis. Mechanistically, SNHG17 and SNORA71B were transcriptionally activated by signal transducer and activator of transcription 5A (STAT5A). SNHG17 positively regulated SNORA71B in PC cell lines and other cell lines. SNHG17 sponged miR-339-5p to upregulate STAT5A and therefore to cause transactivation of SNORA71B. Rescue experiments delineated that SNORA71B was required for the regulation of SNHG17 on PC. Moreover, SNHG17 silence hindered tumorigenesis of PC in vivo. In conclusion, current study first revealed that lncRNA SNHG17 aggravated prostate cancer progression through regulating its homolog SNORA71B via a positive feedback loop, which might do help to the pursuit of better PC treatment.

Long non-coding RNA small nucleolar RNA host gene 6 aggravates pancreatic cancer through upregulation of far upstream element binding protein 1 by sponging microRNA-26a-5p

BACKGROUND

Pancreatic cancer (PC) is a highly deadly malignancy with few effective therapies. We aimed to unmask the role that long non-coding RNA small nucleolar RNA host gene 6 (SNHG6) plays in PC cells by targeting far upstream element binding protein 1 (FUBP1) via microRNA-26a-5p (miR-26a-5p).

METHODS

SNHG6 expression was predicted by bioinformatics, followed by verification via reverse transcription quantitative polymerase chain reaction. Then, the interactions among SNHG6, miR-26a-5p, and FUBP1 were detected through online software analysis, dual luciferase reporter assay and RNA pull-down. After that, cells were treated with different small interfering RNAs and/or mimic to determine the interactions among SNHG6, miR-26a-5p, and FUBP1 and their roles in PC cells. Finally, the role of SNHG6 in tumor growth in vivo was evaluated by measuring the growth and weight of transplanted tumors in nude mice. A t-test, one-way and two-way analysis of variance were used for data analysis.

RESULTS

Compared with that in normal tissues, SNHG6 was highly expressed in PC tissues (1.00 ± 0.05 vs. 1.56 ± 0.06, t = 16.03, P < 0.001). Compared with that in human pancreatic duct epithelial cells (HPDE6-C7), SNHG6 showed the highest expression in PANC-1 cells (1.00 ± 0.06 vs. 3.87 ± 0.13, t = 34.72, P < 0.001) and the lowest expression in human pancreatic cancer cells (MIAPaCa-2) (1.00 ± 0.06 vs. 1.41 ± 0.07, t = 7.70, P = 0.0015). Compared with the levels in the si-negative control group, SNHG6 (0.97 ± 0.05 vs. 0.21 ± 0.06, t = 16.85, P < 0.001), N-cadherin (0.74 ± 0.05 vs. 0.41 ± 0.04, t = 8.93, P < 0.001), Vimentin (0.55 ± 0.04 vs. 0.25 ± 0.03, t = 10.39, P < 0.001), and β-catenin (0.62 ± 0.05 vs. 0.32 ± 0.03, t = 8.91, P < 0.001) were decreased, while E-cadherin (0.65 ± 0.06 vs. 1.36 ± 0.07, t = 13.34, P < 0.001) was increased after SNHG6 knockdown or miR-26a-5p overexpression, accompanied by inhibited cell proliferation, migration, and invasion. SNHG6 overexpression exerted the opposite effects. SNHG6 upregulated FUBP1 expression by sponging miR-26a-5p. Silencing SNHG6 blocked the growth of PC in vivo.

CONCLUSION

Silencing SNHG6 might ameliorate PC through inhibition of FUBP1 by sponging miR-26a-5p, thus providing further supporting evidence for its use in PC treatment.

Downregulation of LINC00665 confers decreased cell proliferation and invasion via the miR-138-5p/E2F3 signaling pathway in NSCLC

Non-small cell lung cancer (NSCLC) is a type of malignant tumor which threatens human health and life. Recently, some researches on long non-coding RNAs (lncRNAs) in NSCLC has elucidated critical regulatory roles in cell proliferation, migration, and invasion, the relative clinical significance and mechanisms of action are still unclear. This study focuses on the important role of a novel lncRNA LINC00665 in the development of NSCLC. Long intergenic non-protein coding RNA 665 gene (LINC00665) was found through microarray analysis and was measured by real-time quantitative PCR (RT-qPCR). The interactions between LINC00665 and miR-138-5p as well as the interactions between miR-138-5p and E2F3 (E2F transcription factor 3) were explored by bioinformatics analysis and dual-luciferase assays. CCK-8, transwell and mouse xenograft assays were performed to investigate the effects of LINC00665 and miR-138-5p on NSCLC proliferation and invasion. As a result, LINC00665 expression was upregulated in NSCLC lung tissues and cells. Downregulated LINC00665 could arrest A549 and H1299 cell proliferation and invasion in vitro, and this finding was recapitulated in vivo. LINC00665 directly regulated the expression of miR-138-5p. Additionally, E2F3 was one of the targets of miR-138-5p; E2F3 without 3'UTR could reverse the inhibitory effects of downregulated LINC00665 on proliferation and invasion in A549 and H1299 cells. In conclusion, dysregulation of LINC00665 plays a vital role in NSCLC progression, indicating that its downregulation may confer decreased cell proliferation and invasion via the miR-138-5p/E2F3 signaling pathway.

Clinicopathological and prognostic value of SNHG6 in cancers: a systematic review and a meta-analysis

BACKGROUND

Dysregulation of the long non-coding RNA small nucleolar RNA host gene 16 (lncRNA SNHG6) has been found in multiple cancers. However, a definite conclusion on the clinical value of lncRNA SNHG6 expression in human cancers has not been determined. The purpose of the present meta-analysis was to comprehensively elucidate the association between SNHG6 expression and clinical outcomes in cancers.

METHODS

A systematic search was performed through the PubMed, Web of Science, Chinese National Knowledge Infrastructure (CNKI), and Wangfang databases for relevant studies. The pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were collected to estimate the prognostic value, and the odds ratios (ORs) with 95% CIs were used to evaluate the relationship between lncRNA SNHG6 expression and clinicopathological features, including tumor invasion depth, lymph node metastasis (LNM), distance metastasis (DM), and TNM stage.

RESULTS

In total, 914 patients from 13 studies were included in this meta-analysis. The pooled results suggested that evaluated SNHG6 expression could predict an unfavorable overall survival (OS) (HR = 2.04, 95% CI:1.56-2.52) with no heterogeneity (I² = 0.0%, p = 0.996). Subgroup analysis indicated a significant association between high SNHG6 expression and shorter OS in those studies with digestive system cancers (HR = 2.05, 95% CI: 1.47-2.62), or with sample size < 70 (HR = 2.70, 95% CI: 1.29-4.11), or with multivariate analysis (HR = 2.04, 95% CI: 1.44-2.64). Moreover, elevated SNHG6 expression was positively associated with tumor invasion depth (OR = 1.76, 95% CI: 1.18-2.63), LNM (OR = 1.60, 95% CI: 1.18-2.17), DM (OR = 1.90, 95% CI: 1.37-2.64) and advanced TNM stage (OR = 1.88, 95% CI: 1.36-2.60) in patients with cancers.

CONCLUSIONS

High lncRNA SNHG6 expression was correlated with tumor invasion depth, LNM, DM, and advanced TNM stage, suggesting that SNHG6 may serve as a promising prognostic biomarker of human cancers.

Long noncoding RNA HOST2, working as a competitive endogenous RNA, promotes STAT3-mediated cell proliferation and migration via decoying of let-7b in triple-negative breast cancer

Background

Human ovarian cancer specific transcript 2 (HOST2) is a long non-coding RNA (lncRNA) reported to be specifically high expressed in human ovarian cancer. However, the mechanism that how HOST2 regulates triple negative breast cancer (TNBC) need to be explored.

Methods

In this study, expression of HOST2 was determined in 40 TNBC patients and matched non-cancerous tissues by qRT-PCR and in situ hybridization (ISH) assay. The biological functions of HOST2 was measured by losing features. The effect of HOST2 on viability, proliferation and migration was evaluated by MTT, colony formation assay, EDU analysis, transwell invasion assay and nude mouse xenograft model. Fluorescence in situ hybridization (FISH), Luciferase report assay, RNA immunoprecipitation (RIP) assay and Western blot were fulfilled to measure molecular mechanisms.

Results

The results showed that HOST2 was up-regulated in BC tissues and cell lines. Clinical outcome analysis demonstrated that high expression of HOST2 was associated with poor prognosis of TNBC patients. Functional experiments illustrated that knockdown of HOST2 significantly suppressed TNBC cell proliferation and migration. Western blot assays, qRT-PCR assays, RIP assays and luciferase reporter assays revealed that HOST2 regulated STAT3 via crosstalk with let-7b. Depression of HOST2 suppressed STAT3-mediated proliferation and migration in TNBC cells. HOST2 could function as a decoy of let-7b to depress expression of STAT3.

Conclusions

HOST2 could function as a oncogene and promoted STAT3-mediated proliferation and migration through acting as a competing endogenous RNA, which might act as a potential biomarker for TNBC patients.

Long Noncoding RNA SNHG6 Promotes Proliferation and Inhibits Apoptosis in Non-small Cell Lung Cancer Cells by Regulating miR-490-3p/RSF1 Axis

Background: Nonsmall cell lung cancer (NSCLC) is a malignant cancer type and has developed into the leading cause of cancer-related death worldwide. Small nucleolar RNA host gene 6 (SNHG6) has been identified as an oncogene in multiple cancers. However, the functions of SNHG6 in tumorigenesis and progression of NSCLC are still poorly understood. Materials and Methods: The expression of SNHG6, miR-490-3p, and remodeling and spacing factor 1 (RSF1) in NSCLC tumors and cells was measured by quantitative real-time polymerase chain reaction. The correlation between miR-490-3p and SNHG6 or RSF1 was analyzed by Pearson's correlation coefficient. Luciferase reporter assay was employed for verifying the interaction between miR-490-3p and SNHG6 or RSF1. Cell viability was examined by 3-(4, 5)-dimethylthiazole-2-y1)-2, 5-biphenyl tetrazolium bromide (MTT) assay. Cell apoptosis was evaluated by flow cytometry and Western blot, respectively. Protein expression of RSF1, Bcl-2, Bax, and cleaved caspase-3 (cleaved casp-3) was detected by Western blot assay. Xenograft mice models were established by subcutaneously injecting H460 cells stably transfected with sh-SNHG6 and sh-NC. Results: SNHG6 and RSF1 expression were upregulated, whereas miR-490-3p was downregulated in NSCLC tumors and cell lines compared with normal tissues and cells. Pearson's correlation coefficient analysis indicated that miR-490-3p was correlated with SNHG6 and RSF1 inversely. Then, luciferase reporter assay confirmed the interaction between miR-490-3p and SNHG6 or RSF1. More importantly, the rescue experiments clarified that miR-490-3p inhibitor could relieve SNHG6 silencing-mediated inhibition on proliferation and promotion on apoptosis in NSCLC. In addition, the authors discovered that SNHG6 promoted cell progression by regulating miR-490-3p/RSF1 axis. However, SNHG6 knockdown hindered tumor growth in vivo by regulating RSF1 by targeting miR-490-3p. Conclusion: The authors demonstrated that SNHG6 promoted proliferation and inhibits apoptosis in NSCLC by regulating miR-490-3p/RSF1 axis, representing promising targeted therapeutic strategies against NSCLC.

Long noncoding RNA SNHG6 promotes proliferation and angiogenesis of cholangiocarcinoma cells through sponging miR-101-3p and activation of E2F8

Cholangiocarcinoma (CCA) development is an extremely complex process with alterations occurring in numerous genes. SNHG6, a validated lncRNA, has been reported to regulate the expression of multiple tumor-related genes in hepatocellular carcinoma, colorectal cancer and breast cancer. Here, we elucidated the function and possible molecular mechanisms of SNHG6 in human CCA cells. Our results proved that the expression SNHG6 was upregulated in CCA tissues and cell lines. Ectopic expression of SNHG6 promoted cell proliferation, cell cycle progression, migration, and angiogenesis in CCA cells, whereas knockdown of SNHG6 repressed these cellular processes. Further mechanistic studies revealed that SNHG6 could compete with the transcription factor E2F8 to bind with miR-101-3p, thus affecting E2F8 expression. Taken together, these results provided a comprehensive analysis of the role of SNHG6 in CCA cells and offered important clues to understand the key roles of competing endogenous RNA (ceRNA) mechanisms in human cholangiocarcinoma.

Long Noncoding RNA SNHG6 Functions as an Oncogene in Non-Small Cell Lung Cancer via Modulating ETS1 Signaling

Background

Non-small cell lung cancer (NSCLC) is a great threat to human health and the biology of the NSCLC still remains largely unknown. Aberrantly expressed long non-coding RNA (lncRNA) Small nucleolar RNA host gene 6 (SNHG6) was involved in the tumorigenesis and progression of various cancers. The aim of this study is to investigate the roles of SNHG6 in NSCLC.

Methods

qRT-PCR and Western blot assays were applied to detect gene expressions. Cell proliferation and migration assays were used to analyze the gene functions. Luciferase reporter assay, RNA Immunoprecipitation assay and Chromatin immunoprecipitation assay were performed to investigate the molecular mechanism.

Results

We found that SNHG6 expression was significantly increased in NSCLC tissues and cell lines and its high expression was correlated with malignant features of NSCLC. In in vitro assays, knockdown of SNHG6 significantly depressed the proliferation vitality and migration activity of NSCLC cells. Research on mechanisms revealed that SNHG6 exerted its tumorigenesis role by promoting ETS1 expression via competitively binding with miR-944 and miR-181d-5p. We also demonstrated that ETS1 enhanced the expression of WIPF1 via binding to its promoter and SNHG6 could thereby regulate the expression of ETS1 target genes including WIPF1, MMP2 and MMP9.

Conclusion

Our study illustrates that SNHG6 is an oncogene in NSCLC and involved in NSCLC tumorigenesis by regulating ETS1 signaling via miR-944 and miR-181d-5p.

Prognostic and clinicopathological significance of SNHG6 in human cancers: a meta-analysis

Background

Recently, accumulating evidence has suggested that the aberrant expression of SNHG6 exists in a variety of tumors and has a correlation with poor clinical outcomes across cancer patients. Considering the inconsistent data among published studies, we aim to assess the prognostic effect of SNHG6 on malignancies.

Methods

We retrieved relevant publications in Web of Science, Embase, MEDLINE, PubMed and Cochrane Library based on predefined selection criteria, up to October 1, 2019. Pooled hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs) were utilized to evaluate the correlation between SNHG6 and overall survival (OS), recurrence-free survival (RFS) and progression-free survival (PFS) as well as clinicopathology.

Results

In total, 999 patients from 14 articles were enrolled in our meta-analysis. The results revealed that augmented SNHG6 expression was significantly correlated with poor OS (HR = 2.20, 95% CI = 1.76–2.75, P < 0.001) and RFS (HR = 3.10, 95% CI = 1.90–5.07, P < 0.001), but not with PFS (HR = 2.11, 95% CI = 0.82–5.39, P = 0.120). In addition to lung cancer and ovarian cancer, subgroup analysis showed that the prognostic value of SNHG6 across multiple tumors was constant as the tumor type, sample size, and methods of data extraction changed. Moreover, cancer patients with enhanced SNHG6 expression were prone to advanced TNM stage (OR = 3.31, 95% CI = 2.46–4.45, P < 0.001), distant metastasis (OR = 4.67, 95% CI = 2.98–7.31, P < 0.001), lymph node metastasis (OR = 2.59, 95% CI = 1.41–4.77, P = 0.002) and deep tumor invasion (OR = 3.75, 95% CI = 2.10–6.69, P < 0.001), but not associated with gender, histological grade and tumor size.

Conclusions

SNHG6 may serve as a promising indicator in the prediction of prognosis and clinicopathological features in patients with different kinds of tumors.

An update review of deregulated tumor suppressive microRNAs and their contribution in various molecular subtypes of breast cancer

BACKGROUND

Breast cancer (BC) is histologically classified into hormone-receptor+ (ER+, PR + ), human epidermal growth factor receptor-2+ (Her2 + ), and triple-negative breast cancer (TNBC) types. The important contribution of tumor-suppressive (TS) microRNAs (miRs) in BC development and treatment have been well-acknowledged in the literature.

OBJECTIVE

The present review focused on the contribution of recently examined TS miRs in the progression and treatment of various histological subtypes of BC.

RESULTS

In summary, various miRs have tumor-suppressive roles in BC, so that their aberrant expression leads to the abnormality in the cellular processes such as enhanced cell growth, decreased apoptosis, cell migration and metastasis, and decreased sensitivity to chemotherapy through deregulated expression of oncogene targets of TS miRs.

CONCLUSION

TS miRs could be regarded as a proper molecular target for target therapy of BC. However, further in vitro and in vivo investigations are required to confirm the exact molecular functions of TS miRs in BC cells to offer more efficient targeted therapies.

LncRNA SNHG6 inhibits cell proliferation and metastasis by targeting ETS1 via the PI3K/AKT/mTOR pathway in colorectal cancer

The term ‘long non-coding RNAs’ (lncRNAs) refers to all non-protein coding transcripts >200 nucleotides in length. Dysregulation of lncRNAs has been identified in colorectal cancer, which is one of the more serious types of cancer worldwide, third place in the mortality rates, and is associated with poor prognoses. Novel evidence suggests that lncRNAs serve an important role in regulating the development and progression of colorectal cancer. In the present study, it was demonstrated that SNHG6 expression was downregulated in colorectal cancer tissues by reverse transcription quantitative polymerase chain reaction assays; however, ETS1 expression levels were upregulated. Overexpression of SNHG6 not only inhibited the proliferation of colon cancer cells in vitro by inducing apoptosis, but also inhibited cell proliferation, invasion and migration. The overexpression of SNHG6 inhibited colon cell viability and proliferation by targeting ETS1 through the phosphoinositide 3-kinase/protein kinase B/mechanistic target of rapamycin signaling pathway. These results suggested that SNHG6 may directly suppress ETS1, which may be one of potential mechanisms through which it inhibits the viability and proliferation of colorectal cancer cells, and it provides novel insight into the carcinogenesis of colorectal cancer. In addition, it may assist in the development of a treatment approach for ETS1-activated colorectal cancer.

Exploring the Molecular Mechanism of the Drug-Treated Breast Cancer Based on Gene Expression Microarray

: Breast cancer (BRCA) remains the leading cause of cancer morbidity and mortality worldwide. In the present study, we identified novel biomarkers expressed during estradiol and tamoxifen treatment of BRCA. The microarray dataset of E-MTAB-4975 from Array Express database was downloaded, and the differential expressed genes (DEGs) between estradiol-treated BRCA sample and tamoxifen-treated BRCA sample were identified by limma package. The pathway and gene ontology (GO) enrichment analysis, construction of protein-protein interaction (PPI) network, module analysis, construction of target genes-miRNA interaction network and target genes-transcription factor (TF) interaction network were performed using bioinformatics tools. The expression, prognostic values, and mutation of hub genes were validated by SurvExpress database, cBioPortal, and human protein atlas (HPA) database. A total of 856 genes (421 up-regulated genes and 435 down-regulated genes) were identified in T47D (overexpressing Split Ends (SPEN) + estradiol) samples compared to T47D (overexpressing Split Ends (SPEN) + tamoxifen) samples. Pathway and GO enrichment analysis revealed that the DEGs were mainly enriched in response to lysine degradation II (pipecolate pathway), cholesterol biosynthesis pathway, cell cycle pathway, and response to cytokine pathway. DEGs (MCM2, TCF4, OLR1, HSPA5, MAP1LC3B, SQSTM1, NEU1, HIST1H1B, RAD51, RFC3, MCM10, ISG15, TNFRSF10B, GBP2, IGFBP5, SOD2, DHF and MT1H) , which were significantly up- and down-regulated in estradiol and tamoxifen-treated BRCA samples, were selected as hub genes according to the results of protein-protein interaction (PPI) network, module analysis, target genes-miRNA interaction network and target genes-TF interaction network analysis. The SurvExpress database, cBioPortal, and Human Protein Atlas (HPA) database further confirmed that patients with higher expression levels of these hub genes experienced a shorter overall survival. A comprehensive bioinformatics analysis was performed, and potential therapeutic applications of estradiol and tamoxifen were predicted in BRCA samples. The data may unravel the future molecular mechanisms of BRCA.

Prognostic value of long non-coding RNA FOXD2-AS1 expression in patients with solid tumors

BACKGROUND

Although increasing evidence has revealed that FOXD2-AS1 overexpression exists in various solid tumors, the value of FOXD2-AS1 as a prognostic marker in such cancers remains uncertain. Accordingly, the present research aimed to assess the association of FOXD2-AS1 with cancer prognosis and predict the biological function of FOXD2-AS1.

METHODS

We systematically retrieved PubMed, PMC, Web of Science, EMBASE and Wiley Online Library databases for eligible articles published up to December 2018. Pooled hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (95%CIs) were calculated to evaluate the correlation of FOXD2-AS1 expression with overall survival (OS), disease free survival (DFS) and clinicopathological characteristics. We also used five Gene Expression Omnibus (GEO) datasets from breast cancer patients to explore the relationship between FOXD2-AS1 expression and prognosis. Finally, we validated FOXD2-AS1 expression in various carcinomas and predicted its biological function based on the public databases.

RESULTS

A total of 13 studies with 2502 tumor patients were included. The pooled HRs demonstrated that FOXD2-AS1 overexpression was significantly associated with unfavorable OS (HR = 1.39, 95%CI: 1.23-1.57, p < 0.001) and DFS (HR = 2.24, 95%CI: 1.55-3.23, p < 0.001) in tumor patients. The pooled ORs indicated that FOXD2-AS1 upregulation was related to large tumor size (OR = 1.53, 95%CI: 1.26-1.85, p < 0.001), deep invasion depth (OR = 1.99, 95%CI: 1.53-2.58, p < 0.001), distant metastasis (OR = 2.03, 95%CI: 1.69-2.43, p < 0.001) and advanced TNM stage (OR = 1.35, 95%CI: 1.06-1.72, p = 0.0150), but not to lymph node metastasis nor differentiation. Moreover, a similar pooled result for the OS of breast cancer patients was obtained (HR = 1.55, 95%CI: 1.14-2.11, p = 0.0052) by analyzing GEO data. Finally, elevated FOXD2-AS1 expression in various solid tumor tissues was verified based on The Cancer Genome Atlas (TCGA) data. Further functional prediction demonstrated that FOXD2-AS1 may participate in some cancer-related pathways.

CONCLUSION

Elevated FOXD2-AS1 expression was associated with poor survival in patients with solid tumors and may serve as a potential prognostic biomarker for a variety of cancers.