lncRNA DSCAM-AS1 downregulates miR-216b to promote the migration and invasion of colorectal adenocarcinoma cells

METTL3-modified lncRNA DSCAM-AS1 promotes breast cancer progression through inhibiting ferroptosis

Numerous studies have indicated that N6-methyladenosine (m6A) and lncRNAs play pivotal roles in human cancer. However, the underlying functions and mechanisms of m6A-lncRNA in the physiological processes of breast cancer remain unclear. Here, we found that DSCAM-AS1 is an m6A-modified lncRNA that was overexpressed in breast cancer tissues and cells, indicating poor clinical prognosis. Gain/loss functional assays suggested that DSCAM-AS1 inhibited erastin-induced ferroptosis in breast cancer cells. Mechanistically, there were remarkable m6A modification sites on both the 3'-UTR of DSCAM-AS1 and the endogenous antioxidant factor SLC7A11. M6A methyltransferase methyltransferase-like 3 (METTL3) methylated both SLC7A11 and DSCAM-AS1. Moreover, DSCAM-AS1 recognized m6A sites on the SLC7A11 mRNA, thereby enhancing its stability. Taken together, these findings indicated a potential therapeutic strategy for breast cancer ferroptosis in an m6A-dependent manner.

Mutual interaction of lncRNAs and epigenetics: focusing on cancer

Long noncoding RNAs are characterized as noncoding transcripts longer than 200 nucleotides in response to a variety of functions within the cells. They are involved in almost all cellular mechanisms so as epigenetics. Given that epigenetics is an important phenomenon, which participates in the biology of complex diseases, many valuable studies have been performed to demonstrate the control status of lncRNAs and epigenetics. DNA methylation and histone modifications as epigenetic mechanisms can regulate the expression of lncRNAs by affecting their coding genes. Reciprocally, the three-dimensional structure of lncRNAs could mechanistically control the activity of epigenetic-related enzymes. Dysregulation in the mutual interaction between epigenetics and lncRNAs is one of the hallmarks of cancer. These mechanisms are either directly or indirectly involved in various cancer properties such as proliferation, apoptosis, invasion, and metastasis. For instance, lncRNA HOTAIR plays a role in regulating the expression of many genes by interacting with epigenetic factors such as DNA methyltransferases and EZH2, and thus plays a role in the initiation and progression of various cancers. Conversely, the expression of this lncRNA is also controlled by epigenetic factors. Therefore, focusing on this reciprocated interaction can apply to cancer management and the identification of prognostic, diagnostic, and druggable targets. In the current review, we discuss the reciprocal relationship between lncRNAs and epigenetic mechanisms to promote or prevent cancer progression and find new potent biomarkers and targets for cancer diagnosis and therapy.

Notch-associated lncRNAs profiling circuiting epigenetic modification in colorectal cancer

Background

Colorectal cancer (CRC) is one of the most prevalent digestive cancers, ranking the 2nd cause of cancer-related fatality worldwide. The worldwide burden of CRC is predicted to rise by 60% by 2030. Environmental factors drive, first, inflammation and hence, cancer incidence increase.

Main

The Notch-signaling system is an evolutionarily conserved cascade, has role in the biological normal developmental processes as well as malignancies. Long non-coding RNAs (LncRNAs) have become major contributors in the advancement of cancer by serving as signal pathways regulators. They can control gene expression through post-translational changes, interactions with micro-RNAs or down-stream effector proteins. Recent emerging evidence has emphasized the role of lncRNAs in controlling Notch-signaling activity, regulating development of several cancers including CRC.

Conclusion

Notch-associated lncRNAs might be useful prognostic biomarkers or promising potential therapeutic targets for CRC treatment.

Therefore, here-in we will focus on the role of “Notch-associated lncRNAs in CRC” highlighting “the impact of Notch-associated lncRNAs as player for cancer induction and/or progression.”

Graphical Abstract

DSCAM-AS1 promotes cervical carcinoma cell proliferation and invasion via sponging miR-338-3p

Deregulated lncRNA DSCAM-AS1 expression was found in several tumors. However, mechanism and functional role of DSCAM-AS1 in cervical carcinoma remain unknown. DSCAM-AS1 was detected in cervical carcinoma specimens and cells by RT-qPCR. CCK-8, Matrigel transwell, and flow cytometry were conducted to determine cell functions. In this research, we firstly we explored DSCAM-AS1 expression in cervical carcinoma cells and specimens. We revealed that DSCAM-AS1 was upregulated in cervical carcinoma lines (C4-1, Caski, Hela, and Siha) compared to GH329 cells. DSCAM-AS1 was upregulated in cervical carcinoma specimens compared to control no-tumor specimens. Overexpression of DSCAM-AS1 induced cervical carcinoma cell growth and cycle. Moreover, our data revealed that miR-338-3p expression was downregulated in cervical carcinoma cells and specimens. There was a negative correlation between miR-338-3p expression and DSCAM-AS1 expression in cervical carcinoma specimens. Elevated expression of miR-338-3p decreased cervical carcinoma cell growth and cycle and invasion. Furthermore, luciferase reporter analysis revealed that miR-338-3p overexpression suppressed luciferase activity of WT-DSCAM-AS1 vector but not the mut-DSCAM-AS1. Ectopic expression of DSCAM-AS1 decreased miR-338-3p expression in the Siha cell. Overexpression of DSCAM-AS1 promoted cervical carcinoma cell growth and cycle via regulating miR-338-3p. These results suggested that DSCAM-AS1 functions as one oncogene through sponging miR-338-3p in cervical carcinoma.

Long non-coding RNA PCED1B-AS1 promotes the proliferation of colorectal adenocarcinoma through regulating the miR-633/HOXA9 axis

Long non-coding RNA (lncRNA) PCED1B-AS1 was shown to play essential roles in human cancers, while its function in colorectal adenocarcinoma remains unclear. This study was carried out to investigate the function of PCED1B-AS1 in regulating the microRNA(miR)-633/HOXA9 axis in colorectal adenocarcinoma. The expression of PCED1B-AS1, miR-633 and HOXA9 was measured by quantitative real-time PCR (qRT-PCR) or Western blot analysis. Cell behaviors of colorectal adenocarcinoma cell lines were assessed by CCK-8, EdU, Transwell and flow cytometry assays. The interaction among PCED1B-AS1, miR-633 and HOXA9 was determined by luciferase reporter and RIP assays. Rescue experiments were performed to determine the regulatory axis in colorectal adenocarcinoma. Moreover, an animal model was established to verify the role of PCED1B-AS1. We found that PCED1B-AS1 was upregulated and miR-633 was downregulated in colorectal adenocarcinoma tissues and corresponding cell lines. Knockdown of PCED1B-AS1 inhibited cell proliferation and promoted apoptosis, while miR-633 inhibitor elevated proliferation and reduced apoptosis of cancer cell lines. In addition, overexpression of HOXA9 obviously attenuated the protective role of knockdown of PCED1B-AS1 or miR-633 mimics in colorectal adenocarcinoma progression. PCED1B-AS1 could negatively regulate the expression of HOXA9 by sponging miR-633. The in vivo experiments confirmed the role of PCED1B-AS1 and miR-633 in colorectal adenocarcinoma, as well as the regulatory relationship of this axis. Our results demonstrated that knockdown of PCED1B-AS1 inhibited the progression of colorectal adenocarcinoma by regulating the miR-633/HOXA9 axis.

Long non-coding RNA DSCAM-AS1 promotes pancreatic cancer progression via regulating the miR-136-5p/PBX3 axis

LncRNA down syndrome cell adhesion molecule antisense 1 (DSCAM-AS1) plays an important role in tumor progression, but its function in pancreatic cancer is unknown. DSCAM-AS1 level was evaluated by in situ hybridization (ISH) assay and qRT-PCR. DSCAM-AS1 was knocked down in pancreatic cancer cells, and its impacts on cell proliferation, invasion, and migration were detected. The binding relationship among DSCAM-AS1, miR-136-5p, and pre-B-cell leukemia homeobox 3 (PBX3) was investigated by bioinformatic analysis and luciferase reporter assay. An in vivo animal model was constructed to determine the role of DSCAM-AS1 in tumor growth. Our results showed that DSCAM-AS1 was elevated in tumor tissues of pancreatic cancer patients and cell lines. DSCAM-AS1 knockdown efficiently inhibited PANC-1 cell proliferation, migration, and invasion and suppressed tumor growth. DSCAM-AS1 could promote PBX3 expression by sponging miR-136-5p, and its function in pancreatic cancer was partially mediated by the miR-136-5p/PBX3 axis. Overall, DSCAM-AS1 knockdown inhibits pancreatic cancer progression by modulating the miR-136-5p/PBX3 axis.

LINC01354/microRNA-216b/KRAS Axis Promotes the Occurrence and Metastasis of Endometrial Cancer

OBJECTIVE

LINC01354 has been defined as a tumor driver in several cancers. Nevertheless, whether LINC01354 involves in endometrial cancer (EC) has been little navigated. Thus, the mechanism of LINC01354 was explored in the disease.

METHODS

Measurements of LINC01354, microRNA (miR)-216b and kirsten rat sarcoma viral oncogene (KRAS) levels in EC tissues and cells were performed. LINC01354 low expression and miR-216b overexpression vectors were introduced into EC cells (lshikawa), thereby their effects on cell viability, apoptosis, migration and invasion were manifested. Rescue experiments were also carried out by down-regulating LINC01354 and miR-216b spontaneously. Tumorigenesis in vivo was also assessed. The relationships of LINC01354/miR-216b/KRAS were analyzed.

RESULTS

Increased LINC01354 and KRAS and reduced miR-216b levels were measured in EC. Silencing LINC01354 or overexpressing miR-216b retarded EC cellular development. LINC01354 counteracted with miR-216b to target KRAS. Suppression of miR-216b antagonized silenced LINC01354-induced impacts on EC cell development. LINC01354/miR-216b/KRAS axis enhanced tumorigenesis in mice with EC.

CONCLUSION

It is testified that silencing LINC01354 inhibits KRAS by up-regulating miR-216b, thereby discouraging cell malignant phenotype in EC.

A Review on the Carcinogenic Roles of DSCAM-AS1

Long non-coding RNAs (lncRNAs) are a group of transcripts with fundamental roles in the carcinogenesis. DSCAM Antisense RNA 1 (DSCAM−AS1) is an example of this group of transcripts which has been firstly identified in an attempt to find differentially expressed transcripts between breast tumor cells and benign breast samples. The pathogenic roles of DSCAM-AS1 have been vastly assessed in breast cancer, yet its roles are not restricted to this type of cancer. Independent studies in non-small cell lung cancer, colorectal cancer, osteosarcoma, hepatocellular carcinoma, melanoma and cervical cancer have validated participation of DSCAM-AS1 in the carcinogenic processes. miR-577, miR-122-5p, miR-204-5p, miR-136, miR−137, miR−382, miR−183, miR−99, miR-3173-5p, miR-874-3p, miR-874-3p, miR-150-5p, miR-2467-3p, miR-216b, miR-384, miR-186-5p, miR-338-3p, miR-877-5p and miR-101 are among miRNAs which interact with DSCAM-AS1. Moreover, this lncRNA has interactions with Wnt/β-catenin pathway. The current study aims at summarization of the results of studies which focused on the assessment of oncogenic role of DSCAM-AS1.

Metastatic colorectal cancer: Perspectives on long non-coding RNAs and promising therapeutics

Metastatic colorectal cancer (mCRC) has long been lethal despite the continuous efforts of researchers worldwide to discover and improve therapeutic regimens. Thanks to the emergence of long non-coding RNAs (lncRNAs), which has strongly reshaped our inherent perspectives on the pathophysiological patterns of disease, research in the field has been reinvigorated. Here, we focus on current understanding of the modes of action of lncRNAs, and review their regulatory roles in metastatic colorectal cancer, and discuss correlated potential lncRNA-based therapeutics. All of the discussed studies share clear and promising perspectives on future diagnostic and therapeutic remedies for metastatic colorectal cancer.

LncRNA TUG1 Regulates Proliferation of Cardiac Fibroblast via the miR-29b-3p/TGF-β1 Axis

Background: Atrial fibrillation (AF) is a very common clinical arrhythmia, accompanied by the overproliferation of cardiac fibroblasts (CFs). This study aimed to investigate the role of the long non-coding RNA(lncRNA) taurine upregulated gene 1 (TUG1) in the proliferation of CFs and further investigated its underlying mechanism.

Methods: One hundred four paroxysmal AF patients and 94 healthy controls were recruited. Human cardiac fibroblasts (HCFs) were applied to establish an AF cell model through treatment with angiotensin II (AngII). qRT-PCR was used for the measurement of gene levels. The cell proliferation was detected by cell counting kit-8 (CCK-8). Luciferase reporter assay was performed for target gene analysis.

Results: Elevated levels of TUG1 and low expression of miR-29b-3p were detected in the serum of AF patients compared with the healthy controls. Pearson's correlation analysis exhibited an inverse relationship between TUG1 and miR-29b-3p expression in AF patients (r = −7.106, p < 0.001). Knockdown of TUG1 inhibited AngII-induced CF proliferation. Taurine upregulated gene 1 (TUG1) functions as a competing endogenous RNA (ceRNA) for miR-29b-3p, and downregulation of miR-29b-3p reversed the role of TUG1 in CF proliferation. TGF-β1 is a direct target gene of miR-29b-3p.

Conclusions: Long non-coding RNA taurine upregulated gene 1 is a key regulator in the occurrence of AF. Slicing TUG1 inhibits CF proliferation by regulating the miR-29b-3p/TGF-β1 axis.

Knockdown of lncRNA PVT1 inhibits the proliferation and accelerates the apoptosis of colorectal cancer cells via the miR‑761/MAPK1 axis

Colorectal cancer (CRC) is associated with high morbidity rates. Long non‑coding RNAs (lncRNAs) participate in the development of CRC. However, the potential roles of lncRNA plasmacytoma variant translocation 1 (PVT1) in CRC remain unknown. Therefore, the aim of the present study was to investigate the potential roles of PVT1 in CRC. Reverse transcription‑quantitative PCR and western blot analyses were conducted to determine the mRNA and protein expression levels. The cellular behaviors were detected using 5‑Ethynyl‑2'‑deoxyuridine, Cell Counting Kit‑8 and flow cytometry assays. The interaction between PVT1 and microRNA (miR)‑761 or MAPK1 was confirmed using a dual‑luciferase reporter assay. Moreover, the Pearson's method was applied for correlation analysis. The results demonstrated that the expression levels of PVT1 and MAPK1 were upregulated, while miR‑761 was downregulated in CRC tissues. The expression of PVT1 was positively correlated with MAPK1 and negatively correlated with miR‑761. In addition, PVT1 sponged miR‑761 to upregulate MAPK1 expression. It was found that the knockdown of PVT1 expression inhibited the proliferation and promoted the apoptosis of CRC cells, which was more potent in cells transfected with miR‑761. The regulatory role of small interfering RNA‑PVT1 on the expression of apoptosis‑related genes was reduced by MAPK1. Collectively, the present results suggested that knockdown of PVT1 may inhibit the progression of CRC by regulating the miR‑761/MAPK1 axis, which may provide a promising biomarker for the treatment of CRC.

Long non-coding RNA Down syndrome cell adhesion molecule-anti-sense 1 promotes gastric carcinoma cell proliferation and migration by regulating the miR-204/TPT1 axis

Background: Several recent studies have suggested that the long non-coding RNA (lncRNA) DSCAM-AS1 (Down syndrome cell adhesion molecule - anti-sense 1) is aberrantly expressed in many malignancies. Purpose: In this study, we aimed to explore the the role of DSCAM-AS1 in gastric carcinoma. Research Design: Expression of DSCAM-AS1 mRNA, miR-204, and TPT1 (Tumor Protein, Translationally-Controlled 1) were detected using quantitative real-time polymerase chain reaction (qRT-PCR). Proliferation and apoptosis of GC cells were determined using the CCK-8 cell counting assay and flow cytometry. The rate of cell migration and invasion was determined using a transwell assay. The relationships between DSCAM-AS1, miR-204, and TPT1 were predicted and confirmed using a dual-luciferase reporter assay. Expression of TPT1 protein was quantified by Western blot. Results: In this study, we found that DSCAM-AS1 was significantly overexpressed in GC tissues and cell lines. Functional experiments indicated that GC cells with DSCAM-AS1 silencing exhibited a dynamic reduction in proliferation and migration. We identified miR-204 as a target of DSCAM-AS1 and found that it targeted TPT1 in GC cells, which further led to decreased expression of miR-204 in GC tissues and cell lines. A rescue assay revealed that knocked-down DSCAM-AS1 hindered GC progression, which was reversed upon miR-204 downregulation or TPT1 overexpression. Conclusion: We conclude that DSCAM-AS1 is expressed as a tumor oncogene in GC progression, modulated via the miR-204/TPT1 axis. These findings indicate the potential of DSCAM-AS1 as a therapeutic target for GC prevention.

Long non-coding RNA (lncRNA) DSCAM-AS1 is upregulated in breast cancer

BACKGROUND

Accumulating evidence highlights that long noncoding RNA (lncRNA) DSCAM-AS1 play a key regulatory role in different stages of cancer development and progression. This study aimed to investigate whether the expression of DSCAM-AS1 is deregulated in breast cancer.

MATERIALS AND METHODS

The relative expression of DSCAM-AS1 was measured in fifty breast cancerous and matched adjacent non-neoplastic tissue samples using quantitative real-time polymerase chain reaction (qPCR) technique. The association between DSCAM-AS1 expression and patients' clinicopathological features was evaluated. Sensitivity and specificity of the DSCAM-AS1 expression for diagnosing breast cancer was obtained by the receiver operating characteristic (ROC) curve analysis.

RESULTS

Our results showed that the expression of DSCAM-AS1 was significantly up-regulated in breast cancerous tissues compared with the matched adjacent non-neoplastic tissues (P < 0.05). Furthermore, we observed a significant association between the DSCAM-AS1 expression and lymph node metastasis (P = 0.011) but no other clinicopathological characteristics (P > 0.05). ROC curve analysis resulted in an area under the curve (AUC) of 0.67 and showed that the DSCAM-AS1 expression level may discriminate cancerous and non-cancerous tissues with 68% sensitivity and 76% specificity.

CONCLUSION

This study provides further evidence that the expression of DSCAM-AS1 is deregulated in breast cancer and highlights its potential in breast cancer development.

Long Noncoding RNA DSCAM-AS1 Facilitates Colorectal Cancer Cell Proliferation and Migration via miR-137/Notch1 Axis

Growing evidences demonstrate that long noncoding RNAs (lncRNAs) participate in various cancers including colorectal cancer (CRC). In the current study, we found that the expression of DSCAM-AS1 in CRC tissues and cell lines was significantly upregulated, and was positively correlated with metastasis status and advanced stage of CRC. In addition, Kaplan-Meier assays also indicated that the expression of DSCAM-AS1 was correlated with poor prognosis in patients with CRC. Silence of DSCAM-AS1 inhibited proliferation and migration of CRC cells. Subcellular fractionation and FISH analyses suggested that DSCAM-AS1 was majorly distributed in cytoplasm of HT29 and LOVO cells. Thus, DSCAM-AS1 might act as a competing endogenous RNA (ceRNA). Subsequently, RT-qPCR results displayed that the expression of miR-137 in CRC tissues was relatively lower than that in the neighboring normal tissues. The interaction between miR-137 and DSCAM-AS1 was demonstrated by luciferase reporter assay. Functionally, miR-137 reversed the pro-proliferation and -metastasis effect of DSCAM-AS1 on CRC cells. Collectively, DSCAM-AS1 promotes CRC progression via sponging miR-137. MiR-137 can suppress the expression of Notch-1, a novel signaling regulating cell proliferation and EMT, by working on the 3'UTR of Notch-1. At last, Notch-1 overexpression or miR-137 inhibition could restore the DSCAM-AS1 silencing-mediated repressive function on cell proliferation and migration. The above data suggested that, DSCAM-AS1 may contribute to CRC cell proliferation and migration by targeting miR-137/Notch-1 axis.

LEMD1-AS1 Suppresses Ovarian Cancer Progression Through Regulating miR-183-5p/TP53 Axis

Background/Aims

Long noncoding RNAs (lncRNAs) play a critical role in tumorigenesis and progression of ovarian cancer (OC). This study focused on the function and potential mechanism toward LEMD1-AS1 (LEMD1 antisense RNA 1) in the progression of ovarian cancer.

Materials and Methods

The expression of LEMD1-AS1 in OC tissues was evaluated in TCGA and Gene Expression Omnibus datasets (GSE119056) and confirmed in OC cell lines via qRT-PCR (quantitative real-time polymerase chain reaction). Then, the location of LEMD1-AS1 in the cytoplasmic and nuclear RNAs extracted from OV cells was detected by qRT-PCR. Cell Counting Kit-8 (CCK-8), colony formation, wound-healing and transwell assays were applied to examine cell viability, proliferation, migration and invasion, respectively. Further, the effect of LEMD1-AS1 on OC tumor growth was determined via subcutaneous xenotransplanted tumor model. The potential target for LEMD1-AS1 was validated via dual-luciferase activity assay, RNA pull-down and RNA immunoprecipitation.

Results

The expression of LEMD1-AS1 was decreased in OC tissues and cell lines. Forced overexpression of LEMD1-AS1 inhibited the proliferation, migration and invasion of ovarian cancer cells and transplanted tumor growth in nude mice. We found that LEMD1-AS1 was mainly located in the cytoplasm of OC cells and contained complementary sites of miR-183-5p. Mechanistically, our results showed that LEMD1-AS1 could directly interact with miR-183-5p and tumor protein p53 (TP53). The anti-tumor role of LEMD1-AS1 on OC progression depended on miR-183-5p-mediated TP53 expression.

Conclusion

LEMD1-AS1 suppresses OC progression through sponging miR-183-5p and regulation of TP53, suggesting a novel biomarker and target for OC.

LncRNA DSCAM-AS1 promotes colorectal cancer progression by acting as a molecular sponge of miR-384 to modulate AKT3 expression

Down Syndrome Cell Adhesion Molecule antisense1 (DSCAM-AS1), a novel long non-coding RNA (lncRNA), reportedly contributes to the development and progression of several cancers. There is a lack of information on its biological role and regulatory mechanism with respect to colorectal cancer (CRC). Here, we discovered that the expression of DSCAM-AS1 exhibited a significant upregulation in CRC tissues and cell lines in comparison with the corresponding control. Increased DSCAM-AS1 expression was associated with poor prognosis for those diagnosed with CRC. Loss-of function assay illustrated that knockdown of DSCAM-AS1 resulted in significant inhibition of cell proliferation, invasion and migration in vitro, and impaired tumor growth in vivo. MicroRNA-384(miR-384) was directly targeted by DSCAM-AS1 in CRC cells, and repression of DSCAM-AS1 inhibited the expression of AKT3, a known target of miR-384 in CRC. In addition, repression of miR-384 or overexpression of AKT3 could partially rescue the inhibitory effect of DSCAM-AS1 knockdown on CRC progression. In summary, DSCAM-AS1 exerted an oncogenic role in CRC by functioning as a competing endogenous RNA of miR-384 to bring about regulation of AKT3 expression. These results implied that DSCAM-AS1 might be a novel therapeutic target for patients suffering from CRC.

Long non-coding RNA DSCAM-AS1 upregulates USP47 expression through sponging miR-101-3p to accelerate osteosarcoma progression

Osteosarcoma (OS) originating from mesenchyme is one of the most common invasive tumors of bone, and has an extremely high mortality rate. Previous studies have reported that long non-coding RNAs (lncRNAs) play essential roles in the tumorigenesis and progression of a multitude of human cancers. The lncRNA DSCAM-AS1 has been reported to be an oncogenic gene in many cancers. However, the roles and regulatory mechanisms of DSCAM-AS1 in OS have not been deeply investigated. In this study, our findings prove that DSCAM-AS1 is highly expressed in OS cells. Knockdown of DSCAM-AS1 suppressed cell proliferation, migration, and invasiveness, and induced cell apoptosis in OS. Additionally, knockdown of DSCAM-AS1 inactivated the Wnt-β-catenin signaling pathway. Moreover, research into its molecular mechanisms confirmed that DSCAM-AS1 functions as a sponge for miR-101-3p, and that ubiquitin-specific peptidase 47 (USP47) is a target gene of miR-101-3p. Furthermore, a negative relationship between miR-101-3p and DSCAM-AS1 or USP47 was discovered. The results from our rescue assays suggest that DSCAM-AS1 regulates the progression of OS through binding with miR-101-3p to control the expression of USP47. Finally, we discovered that AKT-mTOR signaling pathway mediates the activity of DSCAM-AS1 in OS. Taken together, our results show that DSCAM-AS1 accelerates the progression of OS via the miR-101-3p-USP47 axis, which could present a new potential therapeutic treatment for OS.