AKTions by Cytoplasmic lncRNA CASC9 Promote Hepatocellular Carcinoma Survival

Abnormal activation of genomic LINE1 elements caused by DNA demethylation contributes to lncRNA CASC9 overexpression in esophageal squamous cell carcinoma

Long noncoding RNA (lncRNA) cancer susceptibility 9 (CASC9) has been found to be overexpressed and functions as an oncogene in many cancer types. We investigated the molecular mechanism underlying CASC9 overexpression in esophageal squamous cell carcinoma (ESCC). Transcripts containing exons 2 and 6 and exons 4 and 6 showed the highest CASC9 expression levels in ESCC, no transcripts were detected in the normal esophageal epithelial Het1A cell line. The Long Interspersed Nuclear Element-1 (LINE1 or L1) element in the genome was found to participate in the evolution of lncRNA CASC9, the antisense promoter (ASP) of L1 provides the cis-regulatory elements necessary for CASC9 activation, and the antisense chain of L1 participates in the formation of exons of CASC9. The activation of the antisense promoter was due to the aberrant hypomethylation of L1 elements. An active enhancer element was identified in the downstream region of CASC9 gene by ChIP-seq and ChIP-qPCR. The interaction between ASP and the enhancer elements was confirmed by chromosome conformation capture (3C). Thus, our results suggest that the L1 ASP activation due to aberrant hypomethylation and downstream enhancer interaction plays a key role in the overexpression of lncRNA CASC9 in ESCC.

LncRNA CASC9 activated by STAT3 promotes the invasion of breast cancer and the formation of lymphatic vessels by enhancing H3K27ac-activated SOX4

Numerous long noncoding RNAs (lncRNAs) are abnormally expressed in breast cancer (BC), but the underlying mechanisms remain large unknown. Here, we aimed to investigate the functions and mechanisms of lncRNA cancer susceptibility candidate 9 (CASC9) in BC. Western blotting and quantitative real-time PCR (qRT-PCR) were performed to assess gene and protein expression, respectively. The proliferative and metastatic abilities of BC cells were tested by cell counting kit-8 and transwell assays, respectively. The formation of lymphatic vessels was detected by tube formation assay. Chromatin immunoprecipitation (ChIP) and dual luciferase reporter assays were performed to verify molecular interactions. CASC9 was found to be highly expressed in BC tissues and cell lines, and ectopic overexpression was positively associated with tumor volume, TNM stage, and lymph node metastasis. In addition, CASC9 silencing significantly inhibited the proliferation and invasion of BC cells, as well as BC-associated invasion and formation of lymphatic vessels of human dermal lymphatic endothelial cells. Mechanical studies demonstrated that CASC9 could be transcriptionally activated by STAT3 and elevate SOX4 expression by enhancing the acetylation of its promoter region. Our results illustrated that STAT3-activated CASC9 served as a tumor-promoting gene involved in promoting BC invasion and BC-associated formation of lymphatic vessels by upregulating SOX4 through altering H3K27ac level. This finding elucidated a new underlying network of CASC9 in the metastasis of BC.

LncRNA CASC9 promotes proliferation, migration and inhibits apoptosis of hepatocellular carcinoma cells by down-regulating miR-424-5p

INTRODUCTION AND OBJECTIVES

CASC9 and miR-424-5p are closely related with hepatocellular carcinoma (HCC) progression. This study aimed to evaluate the effect of CASC9 involved with miR-424-5p on the development of HCC.

MATERIALS AND METHODS

qRT-PCR was performed to determine the mRNA expressions of CASC9 and miR-424-5p in HCC tissues/cells and adjacent normal tissues/human hepatic epithelial cells, and to analyze the relationship of CASC9 with the clinico-pathological characteristics and prognosis of HCC patients. Then, cell proliferation was measured by CCK-8 and¹ clone formation assays. Apoptosis of HCC cells was measured by flow cytometry. Besides, cell migration and invasion were determined by scratch wound-healing and Transwell assays, respectively. DIANA-LncBase V2 and dual luciferase reporter gene assay were used to verify the targeted relationship between CASC9 and miR-424-5p. Bcl-2, Bax and cleaved caspase-3 expressions were detected by Western blot.

RESULTS

Higher expression of CASC9 was observed in HCC tissues/ cells than in adjacent normal tissues/ human hepatic epithelial cells, and was closely linked to poor prognosis of HCC, tumor size, TNM stage, differentiation degree, lymph node metastasis and alpha-fetoprotein (AFP). Down-regulation of CASC9 decreased the proliferation, invasion and migration of HCC cells while enhancing apoptosis. Besides, CASC9 was negatively correlated with miR-424-5p. MiR-424-5p inhibitor enhanced cell proliferation, invasion and migration while decreasing apoptosis. Interestingly, siRNA-CASC9 partially offset the effects of miR-424-5p inhibitor on HCC cells.

CONCLUSION

CASC9 promoted proliferation, invasion and migration and inhibited apoptosis in HCC cells by inhibiting miR-424-5p.

Long noncoding RNA ZFPM2-AS1 promotes the proliferation, migration, and invasion of hepatocellular carcinoma cells by regulating the miR-576-3p/HIF-1α axis

Long noncoding RNA (LncRNA) zinc finger protein multitype 2 antisense RNA 1 (ZFPM2-AS1) is highly expressed in a variety of tumors and is involved in promoting the malignant biological behaviors of cancer cells. However, the mechanism of ZFPM2-AS1 in the progression of hepatocellular carcinoma (HCC) remains to be explored. The ZFPM2-AS1 expression in HCC was measured by quantitative real-time PCR (qRT-PCR); cell counting kit-8, 5-bromo-2'-deoxyuridine (BrdU), and transwell assays were used to confirm the biological functions of ZFPM2-AS1 in regulating the malignant biological behaviors of HCC cells; the luciferase reporter gene assay was employed to detect whether ZFPM2-AS1 could bind to microRNA (miR)-576-3p; the regulatory relationship between ZFPM2-AS1 and miR-576-3p was probed by qRT-PCR; the effects of ZFPM2-AS1 and miR-576-3p on the expression of hypoxia-inducible factor 1α (HIF-1α) were detected by qRT-PCR and Western blot. The expression of ZFPM2-AS1 in HCC tissues, compared with that in normal liver tissues, was significantly upregulated. Knockdown of ZFPM2-AS1 markedly inhibited HCC cell proliferation, migration, and invasion while the overexpression of ZFPM2-AS1 worked oppositely. miR-576-3p could reverse the effects of ZFPM2-AS1 on the biological behaviors of HCC cells. Besides, ZFPM2-AS1 could bind to miR-576-3p and positively regulate the expression of HIF-1α, a target gene of miR-576-3p, by adsorbing miR-576-3p. ZFPM2-AS1 is abnormally highly expressed in HCC and facilitates proliferation, migration, and invasion of HCC cells by adsorbing miR-576-3p and upregulating HIF-1α expression.

Oncogenic LncRNA CASC9 in Cancer Progression

BACKGROUND

Long non-coding RNAs (LncRNAs), with the length of over 200 nucleotides, that originate from intergenic, antisense, or promoter-proximal regions, are a large family of RNAs that lack coding capacity. Emerging evidences illustrated that LncRNAs played significant roles in a variety of cellular functions and biological processes in profuse human diseases, especially in cancers. Cancer susceptibility candidate 9 (CASC9), as a member of the LncRNAs group, firstly found its oncogenic function in esophageal cancer. In the following recent studies, a growing amount of human malignancies are verified to be correlated with CASC9, most of which are derived from the squamous epithelium tissue. This present review attempts to highlight the latest insights into the expression, functional roles, and molecular mechanisms of CASC9 in different human malignancies.

METHODS

In this review, the latest findings related to the pathophysiological processes of CASC9 in human cancers were summarized and analyzed, and the associated studies collected in systematic retrieval of PubMed used lncRNA and CASA9 as keywords.

RESULTS

CASC9 expression is identified to be aberrantly elevated in a variety of malignancies. The over-expression of CASC9 has been suggested to accelerate cell proliferation, migration, cell growth and drug resistance of cancer cells, while depressing cell apoptosis, revealing its role as an oncogene. Moreover, the current review demonstrated CASC9 as closely related to the neoplastic transformation of squamous epithelial cells and squamous metaplasia in non-squamous epithelial tissues. Finally, we discuss the limitations and tremendous diagnostic/ therapeutic potential of CASC9 in various human cancers.

CONCLUSION

Long non-coding RNA CASC9 likely serve as useful disease biomarkers or therapeutic targets which be effectively applied in the treatment of different kinds of cancers.

Long non-coding ribonucleic acid W5 inhibits progression and predicts favorable prognosis in hepatocellular carcinoma

BACKGROUND

Accumulating evidence has revealed that several long non-coding ribonucleic acids (lncRNAs) are crucial in the progress of hepatocellular carcinoma (HCC).

AIM

To classify a long non-coding RNA, i.e., lncRNA W5, and to determine the clinical significance and potential roles of lncRNA W5 in HCC.

METHODS

The results showed that lncRNA W5 expression was significantly downregulated in HCC cell lines and tissues. Analysis of the association between lncRNA W5 expression levels and clinicopathological features suggested that low lncRNA W5 expression was related to large tumor size (P < 0.01), poor histological grade (P < 0.05) and serious portal vein tumor thrombosis (P < 0.05). Furthermore, Kaplan-Meier survival analysis showed that low expression of lncRNA W5 predicts poor overall survival (P = 0.016).

RESULTS

Gain-of-loss function experiments, including cell counting kit8 assays, colony formation assays, and transwell assays, were performed in vitro to investigate the biological roles of lncRNA W5. In vitro experiments showed that ectopic overexpression of lncRNA W5 suppressed HCC cell proliferation, migration and invasion; conversely, silencing of lncRNA W5 promoted cell proliferation, migration and invasion. In addition, acting as a tumor suppressor gene in HCC, lncRNA W5 inhibited the growth of HCC xenograft tumors in vivo.

CONCLUSION

These results showed that lncRNA W5 is down-regulated in HCC, and it may suppress HCC progression and predict poor clinical outcomes in patients with HCC. LncRNA W5 may serve as a potential HCC prognostic biomarker in addition to a therapeutic target.

Identification of a Nine Immune-Related lncRNA Signature as a Novel Diagnostic Biomarker for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) ranks fifth among common cancers and is the second most common cause of cancer-related mortality worldwide. This study is aimed at identifying an immune-related long noncoding RNA (lncRNA) signature as a potential biomarker with prognostic value to improve early diagnosis and provide potential therapeutic targets for HCC patients. The subjects of this study were HCC samples with complete transcriptome data and clinical information downloaded from The Cancer Genome Atlas (TCGA) database. We then extracted the immune-related mRNA and lncRNA expression profiles. Based on the expression profiles of immune-related lncRNAs, we identified a nine-lncRNA signature that was related to the progression of HCC. The risk score was calculated based on the expression level of the nine lncRNAs of each sample, which divided patients into high-risk and low-risk groups. We found that the increased risk score was associated with a poor prognosis of HCC patients. To assess the accuracy of the survival model, we calculated a receiver operating characteristic (ROC) for validation. The curve showed that the area under the curve (AUC) for the risk score was 0.792. Besides, both principal component analysis (PCA) and gene set enrichment analysis (GSEA) were further used for functional annotation. We found that the distribution patterns were different between the low-risk and high-risk groups in PCA, and the underlying mechanism by which the nine lncRNAs promoted the progression of HCC involved an abnormal immune status. Finally, we analyzed the infiltration of twenty-nine kinds of immune cells and the activation of immune function in HCC using the ssGSEA algorithm. The results showed that aDCs, iDCs, macrophages, Tfh, Th1, Treg, and NK cells were correlated with the progress of HCC patients. And the immune functions including APC costimulation, CCR, check point, HLA, MHC class I, and Type II IFN responses were also significantly different between the high-risk and low-risk groups. In conclusion, our study identified a nine-lncRNA signature with potential prognostic value for patients with HCC, which could be used as a new biomarker for the diagnosis and immunotherapy of HCC.

Silencing long non-coding RNA CASC9 inhibits colorectal cancer cell proliferation by acting as a competing endogenous RNA of miR-576-5p to regulate AKT3

Increasing studies have shown that long non-coding RNAs (lncRNAs) are regarded as important regulators in the occurrence and development of colorectal cancer (CRC). Although lncRNA CASC9 has been studied in CRC, the detailed regulatory mechanism of CASC9 in CRC is still unclear. In this study, we found that CASC9 was significantly upregulated in CRC tissues and cell lines compared to normal controls and that aberrant expression was associated with the tumor-node-metastasis (TNM) stage of CRC. Functionally, CASC9 depletion efficiently inhibited the proliferation of CRC cells and induced cell apoptosis in vitro. Mechanistically, CASC9 was mainly enriched in the cytoplasm of CRC cells and interacted directly with miR-576-5p. Downregulation of miR-576-5p reversed the inhibitory effect of CASC9 siRNA on CRC cell progression. Furthermore, AKT3 has been identified as a downstream target of miR-576-5p. Spearman’s correlation analysis revealed that AKT3 was negatively correlated with miR-576-5p but positively correlated with CASC9. Downregulation of miR-576-5p restored the effect of CASC9 silencing on AKT3 expression. Therefore, silencing CASC9 could downregulate the expression of AKT3 by reducing the competitive binding of CASC9 to miR-576-5p, thus suppressing CRC cell proliferation and promoting cell apoptosis. In summary, we identified CASC9 as an oncogenic lncRNA in CRC and defined the CASC9/miR-576-5p/AKT3 axis, which might be considered a potential therapeutic target for CRC patients, as a novel molecular mechanism implicated in the proliferation and apoptosis of CRC.

All-Trans Retinoic Acid Rescues the Tumor Suppressive Role of RAR-β by Inhibiting LncHOXA10 Expression in Gastric Tumorigenesis

Numerous long noncoding RNAs (LncRNAs) were having recently been shown to be involved in cancer development, including gastric cancer (GC). However, the precise mechanism and treatments to target these molecules have rarely been studied. Thus, we aimed to investigate the function of LncHOXA10 in gastric tumorigenesis and targeted therapy. First, we measured the differences in LncHOXA10 and retinoic acid receptor β (RAR-β) levels in gastric cancer tissues and cell lines compared with those in noncancerous tissues and cell lines. We observed that LncHOXA10 was significantly upregulated in gastric cancer tissues and cell lines, whereas RAR-β showed the opposite trend. Subsequently, loss and gain of LncHOXA10 cell lines were constructed to determine whether LncHOXA10 plays a role in gastric tumorigenesis. The results showed that LncHOXA10 promoted the proliferation, migration, and invasion of cells, whereas apoptosis was markedly inhibited. Subsequently, mechanistic investigations revealed that LncHOXA10 can repress RAR-β expression and that all-trans retinoic acid (ATRA) can rescue the expression of RAR-β. Finally, we showed that ATRA can reverse the pro-cancerous function of LncHOXA10. We showed that LncHOXA10 may be a prognostic and therapeutic factor of gastric cancer by negatively regulating RAR-β. Furthermore, ATRA can inhibit the role of LncHOXA10 in gastric tumorigenesis.

Long non-coding RNA CASC9 promotes the progression of retinoblastoma via interacting with miR-145-5p

Abnormal expression of long non-coding RNA cancer susceptibility candidate 9 (CASC9) has been found to play vital roles in many human tumors. However, the role and the regulatory mechanism of CASC9 have not yet been demonstrated in retinoblastoma (RB). Hence, we performed this study to explore the function and mechanism of CASC9 in RB. CASC9 expression was firstly detected in human RB tissues and cells. The influence of CASC9 on the malignant phenotypes of RB cells, including cell proliferation, invasion, epithelial-mesenchymal transition (EMT) and apoptosis, was analyzed by overexpressing or silencing CASC9. The association between CASC9, miR-145-5p and E2F transcription factor 3 (E2F3) was determined by dual-luciferase reporter assay and RNA immunoprecipitation. We found that CASC9 expression was elevated in RB tissues and cells. Overexpression of CASC9 significantly facilitated the proliferation, invasion and EMT of RB cells. On the contrary, knockdown of CASC9 inhibited the proliferation, invasion and EMT, while enhanced the apoptosis of RB cells. CASC9 acted as a competing endogenous RNA (ceRNA) for miR-145-5p to regulate E2F3. Additionally, miR-145-5p inhibitor and E2F3 overexpression both partly reversed the malignant phenotypes of RB cells affected by CASC9 knockdown. However, miR-145-5p overexpression further strengthened these features induced by CASC9 downregulation. These findings suggested that CASC9 contributed to RB development by regulating E2F3 via sponging miR-145-5p. CASC9 might be a possible therapeutic target for RB.

The Prognostic Signature and Potential Target Genes of Six Long Non-coding RNA in Laryngeal Squamous Cell Carcinoma

Studies have shown that long non-coding RNA (lncRNA) may act as the carcinogenic factor or tumor suppressor of laryngeal squamous cell carcinoma (LSCC). This study aims to identify the prognostic value and potential target protein-coding genes (PCGs) of lncRNAs in LSCC. The LSCC datasets were collected from The Cancer Genome Atlas (TCGA). Statistical and bioinformatic methods were used to establish and evaluate the prognostic model, identify the correlation between lncRNAs and clinical characteristics, and screen for PCGs co-expressed with lncRNAs. Weighted gene co-expression network analysis (WGCNA) identified PCG modules associated with clinical characteristics. The expression of lncRNAs and PCGs was analyzed using our LSCC patients by RT-qPCR. LINC02154, LINC00528, SPRY4-AS1, TTTY14, LNCSRLR, and KLHL7-DT were selected to establish the prognostic model. The overall survival (OS) of low-risk patients forecasted by the model was significantly better than high-risk patients. Receiver operating characteristic (ROC) curve and concordance index (C-index) validated the accuracy of the prognostic model. Chi-square test showed that six lncRNAs were associated with one of the clinical characteristics, i.e., gender, clinical stage, T and N stage, respectively. WGCNA identified PCG modules associated with gender, clinical stage, T and N stage. We took the intersection of the PCG modules of WGCNA, the differentially expressed PCGs between LSCC and normal samples, and the PCGs co-expressed with six lncRNAs. The intersection PCGs survival analysis showed that four PCGs, i.e., STC2, TSPAN9, SMS, and TCEA3 affected the OS of LSCC. More importantly, the differential expression of six lncRNAs and four PCGs between LSCC and normal samples was verified by our LSCC patients. In conclusion, we successfully established a prognostic model based on six-lncRNA RiskScore and initially screened the potential target PCGs of six lncRNAs for further basic and clinical research.

Long Non-coding RNA LINC01420 Contributes to Pancreatic Cancer Progression Through Targeting KRAS Proto-oncogene

BACKGROUND

Long non-coding RNAs (lncRNAs) have been increasingly uncovered to participate in multiple human cancers, including pancreatic cancer (PC). However, the underlying mechanisms of most of the lncRNAs have not been fully understood yet.

AIMS

In this study, we probed the role and latent mechanism of LINC01420 in PC.

METHODS

Several online tools were applied. Gene expression was evaluated by qRT-PCR or Western blot. Both in vitro and in vivo assays were conducted to probe LINC01420 function in PC. ChIP, RIP, and luciferase reporter assays were performed to determine relationships between genes.

RESULTS

The bioinformatics analyses revealed LINC01420 was highly expressed in PC tissues. Besides, LINC01420 was pronouncedly upregulated in PC cell lines and its depletion controlled PC cell proliferation and EMT in vitro and hindered tumor growth in vivo. Importantly, KRAS was proved to mediate LINC01420-facilitated PC cell proliferation. Further, we explained that KRAS transcription was regulated by MYC, while LINC01420 enhanced the binding of MYC to KRAS promoter in the nucleus of PC cells. Intriguingly, LINC01420 boosted MYC expression in the cytoplasm of PC cells by sponging miR-494-3p.

CONCLUSION

This study illustrated that LINC01420 accelerates PC progression through releasing miR-494-3p-silenced MYC in cytoplasm and upregulating MYC-activated KRAS in nucleus, unveiling LINC01420 as a latent therapeutic strategy for PC patients.

LncRNA CASC9 Affects Cell Proliferation, Migration, and Invasion of Tongue Squamous cell Carcinoma via Regulating miR-423-5p/SOX12 Axes

Introduction

The incidence of tongue squamous cell carcinoma (TSCC) has increased in recent decades. However, the function of long non-coding RNA (lncRNA) CASC9 in the occurrence and progression of TSCC is unclear. In this work, we attempted to clarify the role of lncRNA CASC9 in determining the phenotype of TSCC cells, and to clarify the underlying mechanisms.

Methods

We used qRT-PCR analysis to identify the level of CASC9 mRNA expression in TSCC clinical samples and cell lines. We investigated cell proliferation, and cell migration and invasion of TSCC cells transfected with siCASC9 or siNC using CCK-8 and transwell assays. Bioinformatics analysis and a luciferase reporter assay were employed to predict and verify the target microRNA (miRNA).

Results

CASC9 was up-regulated in the TSCC tissues and cells, and predicted a poor prognosis. CASC9 silencing significantly inhibited cell proliferation, migration, and invasion of the TSCC cells compared with the non-targeting control small interfering RNA (siCtrl) treatment. miR-423-5p was predicted as the targeting miRNA of CASC9; this was verified by a luciferase reporter assay. CASC9 expression showed a negative correlation with miR-423-5p expression and a positive correlation with SOX12 expression. The miR-423-5p inhibitor can rescue the carcinogenesis effect of CASC9 on TSCC cells.

Conclusion

Our work indicates that CASC9 plays a role in TSCC tumorigenesis; this novel information will improve TSCC molecular targeting therapy.

Diagnostic and prognostic value of lncRNA cancer susceptibility candidate 9 in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a common malignant gastrointestinal tumor. There are currently few clinical diagnostic and prognostic markers for HCC. LncRNA cancer susceptibility candidate 9 (CASC9) is a long-chain non-coding RNA discovered in recent years, and previous studies have found that lncRNA CASC9 participates in the occurrence and development of HCC, but its clinical value remains unclear.

AIM

To determine the expression of lncRNA CASC9 in HCC and its diagnostic and prognostic value.

METHODS

Data on CASC9 expression in patients with HCC were collected from the Cancer Genome Atlas (TCGA) database to analyze the relationship between CASC9 and patient survival. A total of 80 HCC patients treated in The First Affiliated Hospital of Guangxi Medical University from May 2012 to January 2014 were enrolled in the patient group, and 50 healthy subjects were enrolled in the control group during the same period. CASC9 expression in the two groups was determined using quantitative real-time polymerase chain reaction, and its diagnostic and prognostic value was analyzed based on the CASC9 data and pathological data in these HCC patients. The relationship between CASC9 and patient survival was assessed during the 5-year follow-up period.

RESULTS

Analysis of data from TCGA database revealed that control samples showed significantly lower CASC9 expression than carcinoma tissue samples (P < 0.001); the low CASC9 expression group had a higher survival rate than the high CASC9 expression group (P = 0.011), and the patient group showed significantly increased expression of serum CASC9, with the area under the curve (AUC) of 0.933. CASC9 expression was related to tumor size, combined hepatitis, tumor, node, metastasis (TNM) staging, lymph node metastasis, differentiation and alpha fetoprotein, and the high CASC9 expression group showed lower 1-year, 3-year and 5-year survival rates than the low CASC9 expression group (all ^aP < 0.05). Multivariate Cox regression analysis revealed that TNM staging, lymph node metastasis, differentiation, alpha fetoprotein and CASC9 were independent factors affecting the prognosis of patients. Stage I+II patients with lymph node metastasis, low differentiation, and alpha fetoprotein > 200 ng/mL had a poor 5-year survival rate.

CONCLUSION

High CASC9 expression is beneficial in the prognosis of HCC patients. CASC9 is expected to be a potential diagnostic and prognostic indicator of HCC.

lncRNA SNHG7 affects malignant tumor behaviors through downregulation of EZH2 in uveal melanoma cell lines

Previous studies have demonstrated that the long non-coding RNA, small nucleolar RNA host gene 7 (SNHG7) plays an important role in several types of cancer; however, its role in the development of uveal melanoma (UM) remains unclear. The present study investigated the effect of SNHG7 on the prognosis of UM, as well as on cell proliferation, cell cycle and apoptosis of UM cell lines. Furthermore, the present study aimed to determine the molecular mechanisms underlying these effects. The association between SNHG7 and prognosis of UM was analyzed using detailed SNHG7 mRNA expression data and clinical information from The Cancer Genome Atlas database. Reverse transcription-quantitative PCR was used in order to detect the differential expression of SNHG7 in UM tissues and cell lines. Cell proliferation was detected using Cell Counting Kit-8 assays, following overexpression of SNHG7. A cell cycle assay was performed using propidium iodide/RNase staining. An apoptosis assay was performed using the Annexin-V-Fluorescein isothiocyanate apoptosis detection kit. The expression of enhancer of zeste homolog 2 (EZH2) was measured via western blotting. The results of the present study indicated that low expression of SNHG7 was associated with poor prognosis. Furthermore, increasing the expression of SNHG7 inhibited the proliferation of UM cells, suppressed cell cycle progression and promoted apoptosis. Western blot analysis results revealed that overexpression of SNHG7 downregulated EZH2 protein expression levels in UM cell lines. The results of the present study demonstrated that SNHG7 inhibited malignant transformation of UM cells by regulating EZH2 expression.

Long Non-Coding RNA CASC9 And HIF-1α Form A Positive Feedback Loop To Facilitate Cell Proliferation And Metastasis In Lung Cancer

Background

The long noncoding RNA cancer susceptibility 9 (CASC9) has been recognized as an important modulator of cell growth and metastasis in many cancers. However, its detailed roles in lung cancer remain unclear. In this study, we aimed to investigate its functions and molecular mechanism in lung cancer progression.

Methods

Expression of CASC9 was determined in lung cancer tissues and cell lines by real-time PCR. CCK-8, colony formation, wound healing and transwell assays were done to evaluate the cell proliferation, migration and invasion capacities in vitro. Real-time PCR, Western blot and RNA immunoprecipitation (RIP) assays were performed to dissect the mechanisms.

Results

CASC9 was overexpressed in lung cancer specimens and cell lines. Knockdown of CASC9 inhibited cell proliferation, migration, invasion and EMT in lung cancer cells. While overexpression of CASC9 in normal lung epithelial cells did the opposite. CASC9 interacted with HIF-1α and enhanced its protein stability. They formed a positive feedback loop by reciprocally inducing each other expression and regulated cell proliferation and metastasis.

Conclusion

Our findings demonstrated a novel regulatory signaling pathway, namely the CASC9/HIF-1α axis, which was involved in lung cancer progression. These findings can provide valuable insights on the potential therapy application for lung cancer.

Long noncoding RNA DLGAP1-AS1 promotes cell proliferation in hepatocellular carcinoma via sequestering miR-486-5p

Hepatocellular carcinoma (HCC) is most prevalent tumor in liver and one of the most fatal cancers in the world. Long noncoding RNAs (lncRNAs) have been accepted as important regulators in carcinomas. But there are still many lncRNAs including DLGAP1-AS1 unannotated in HCC. First of all, GEPIA suggested that DLGAP1-AS1 presented high expression in HCC tissue samples relative to the normal tissues. Besides, overexpression of DLGAP1-AS1 was also proved in HCC cell lines. Moreover, DLGAP1-AS1 knockdown efficiently suppressed cell proliferation in HCC. Interestingly, miR-486-5p was predicted and validated to interact with DLGAP1-AS1, while the level of miR-486-5p was significantly increased In HCC after DLGAP1-AS1 knockdown. Moreover, we uncovered that ectopic expression of miR-486-5p induced suppression on HCC cell proliferation and that miR-486-5p inhibition offset the effect of DLGAP1-AS1 silence on HCC cell proliferation and apoptosis. Furthermore, H3F3B was identified as target of miR-486-5p and was therefore positively regulated by DLGAP1-AS1 in HCC. Of note, H3F3B upregulation partly revived the declined cell proliferative capacity in response to DLGAP1-AS1 knockdown. To conclude, DLGAP1-AS1 exerted its oncogenic role in HCC via miR-486-5p/H3F3B axis. Our new findings provided novel theoretical basis for discovery of therapeutic targets of HCC.

Long noncoding RNA STXBP5-AS1 inhibits cell proliferation, migration, and invasion via preventing the PI3K/AKT against STXBP5 expression in non-small-cell lung carcinoma

Long noncoding RNAs participate in carcinogenesis and tumor progression in non-small-cell lung carcinoma (NSCLC), but the mechanisms underlying NSCLC tumorigenesis remain to be fully elucidated. Here, we reported the functional role and potential mechanism of long noncoding RNA syntaxin-binding protein 5-antisense RNA 1 (STXBP5-AS1) in NSCLC. First, our data revealed that the expression levels of STXBP5-AS1 in 31 NSCLC tissues were lower than in adjacent tissues using quantitative polymerase chain reaction (qPCR) and its expression was significantly associated with tumor metastasis of NSCLC patients. Moreover, CCK-8, scratch wound healing and transwell assay suggested that upregulation of STXBP5-AS1 repressed the proliferation, migration, and invasion in A549, NCI-H292, and NCI-H460 cells. To explore the potential mechanism of STXBP5-AS1 in NSCLC, we first investigated the relationship among STXBP5-AS1, STXBP5, and AKT1 in A549 cells. Results indicated that STXBP5-AS1 was negatively related with STXBP5 and AKT1 at messenger RNA expression level using qPCR. In addition, we observed that STXBP5-AS1 had reverse effects on the protein levels of STXBP5 and phosphorylated AKT1 (p-AKT1) in A549 cells via Western blot assay, despite no significant effects on AKT1. Subsequently, LY294002, as the phosphatidylinositol 3 kinase/protein kinase B (PI3K/AKT) pathway inhibitor, was used to further confirm the regulatory mechanism of STXBP5-AS1, which showed that knockdown of STXBP5-AS1 could rescue the expression of STXBP5 and p-AKT1 protein expression levels in A549 cells. Taken together, our results suggested that STXBP5-AS1, as a tumor suppressor, inhibits cell proliferation, migration, and invasion by preventing the PI3K/AKT against STXBP5 expression in NSCLC.

Long noncoding RNA CASC9 promotes LIN7A expression via miR-758-3p to facilitate the malignancy of ovarian cancer

The long noncoding RNA cancer susceptibility 9 (CASC9) has been reported to be a pivot modulator in growth and metastasis of breast cancer, liver cancer, esophageal squamous cell carcinoma, lung adenocarcinoma, gastric cancer, and nasopharyngeal cancer. However, its potential roles in ovarian cancer remain unclear. In this study, we aimed at its functions and molecular mechanism in ovarian cancer progression. We showed that CASC9 was highly expressed in ovarian cancer tissues and cell lines. An elevated level of CASC9 predicts an unfavorable prognosis in patients with ovarian cancer. Loss-of-function and gain-of-function assays illustrated that CASC9 promotes ovarian cancer cell proliferation, migration, and invasion in vitro, and accelerates tumor growth in vivo. We showed that CASC9 works as a competing endogenous RNA (ceRNA) for miR-758-3p which targets LIN7A. CASC9 inhibits the level of miR-758-3p, and in turn stimulates LIN7A expression in ovarian cancer. Overexpression of LIN7A reverses the suppressive roles of CASC9 depletion on ovarian cancer. In sum, our findings reveal a novel undefined regulatory signaling pathway, namely CASC9/miR-758-3p/LIN7A axis, involved in ovarian cancer progression.