LINC00261 suppresses human colon cancer progression via sponging miR-324-3p and inactivating the Wnt/β-catenin pathway

Growing evidence indicates long noncoding RNAs (lncRNAs) are significant regulators in the progression of various malignant tumors including colon cancer. Dysregulation of lncRNA LINC00261 has been identified in many cancers. Investigations on LINC00261 function have revealed that LINC00261 could act as a crucial tumor suppressor in various cancers. But, the biological involvement of LINC00261 in colon cancer is still barely known. Here, we found LINC00261 was reduced in colon cancer cells. Meanwhile, overexpressed LINC00261 repressed colon cancer cell viability and proliferation capacity. In addition, colony cancer cell colony formation was inhibited and apoptosis was enhanced by upregulation of LINC00261. Also, colon cancer cell migration and invasion both were restrained by LINC00261. miR-324-3p can exert important functions in several carcinomas, but its role in colon cancer is uninvestigated. In the current study, miR-324-3p was examined and miR-324-3p was greatly increased in colon cancer cells. Moreover, the association between miR-324-3p and LINC00261 was confirmed via performing RNA immunoprecipitation and RNA-pull-down experiments. In cancer biology, aberrant modulation of the Wnt signaling pathway remains a prevalent theme. Overexpression of LINC00261 obviously impaired colon cancer progression via inactivating the Wnt pathway. Furthermore, in the xenograft model assay, an increase of LINC00261 could suppress colon tumor growth via sponging miR-324-3p and inactivating the Wnt pathway. Overall, our results showed that LINC00261 repressed colon cancer progression via regulating miR-324-3p and the Wnt pathway. LINC00261 could be established as a novel therapeutic target for colon cancer.     

LINC01133 aggravates the progression of hepatocellular carcinoma by activating the PI3K/AKT pathway

LncRNAs exhibit crucial roles in various pathological diseases, including hepatocellular carcinoma (HCC). Therefore, it is significant to recognize the dysregulated lncRNAs in HCC progression. Recently, LINC01133 has been identified in several tumors. However, the biological role of LINC01133 in HCC remains poorly understood. Currently, we focused on the function of LINC01133 in HCC development. We observed that LINC01133 was significantly increased in HCC cells including HepG2, Hep3B, MHCC-97L, SK-Hep-1, and MHCC-97H cells compared with the normal human liver cell line HL-7702. In addition, PI3K/AKT signaling was highly activated in HCC cells. Knockdown of LINC01133 was able to inhibit HCC cell proliferation, cell colony formation, cell apoptosis, and blocked cell cycle arrest in the G1 phase. For another, downregulation of LINC01133 repressed HCC cell migration and invasion. Subsequently, the PI3K/AKT signaling pathway was strongly suppressed by silence of LINC01133 in Hep3B and HepG2 cells. Then, in vivo tumor xenografts models were established using Hep3B cells to explore the function of LINC01133 in HCC progression. Consistently, our study indicated that knockdown of LINC01133 dramatically repressed HCC tumor progression through targeting the PI3K/AKT pathway in vivo. Taken these together, we revealed that LINC01133 contributed to HCC progression by activating the PI3K/AKT pathway.     

Down-regulated expression of LINC00518 prevents epithelial cell growth and metastasis in breast cancer through the inhibition of CDX2 methylation and the Wnt signaling pathway

Breast cancer (BC)-related mortality is associated with the potential metastatic properties of the primary breast tumors. The following study was conducted with the main focus on the effect of LINC00518 on the growth and metastasis of BC epithelial cells via the Wnt signaling pathway through regulation of the methylation of CDX2 gene. Initially, differentially expressed long intergenic non-protein coding RNAs (lincRNAs) related to BC were screened out in the Cancer Genome Atlas (TCGA) database, after which we detected the LINC00518 expression and localization in BC tissues and cells. Then the CDX2 positive expression and methylation level were identified. The targeting relationship of LINC00518 and CDX2, and binding methyltransferase in the promoter region were examined. BC epithelial cell proliferation, colony formation ability, invasion, migration and apoptosis were further evaluated. The lincRNA expression data related to BC downloaded from the TCGA database revealed that there was a high expression of LINC00518 in BC, and a negative correlation between LINC00518 and CDX2. In addition, LINC00518 promotes CDX2 methylation by recruiting DNA methyltransferase through activating the Wnt signaling pathway. The down-regulation of LINC00518 inhibited proliferation, invasion, migration, and EMT of BC epithelial cells while enhancing apoptosis. The inhibitory effects of LINC00518 down-regulation was reversed by CDX2 down-regulation. In conclusion, our findings revealed that down-regulation of LINC00518 might have the ability to suppress BC progression by up-regulating CDX2 expression through the reduction of methylation and blockade of the Wnt signaling pathway, resulting in the inhibition of proliferation and promotion of apoptosis of BC epithelial cells.     

Sevoflurane protects cardiomyocytes against hypoxia/reperfusion injury via LINC01133/miR-30a-5p axis

Previous studies failed to elucidate the detailed mechanisms of anesthetic preconditioning as a protective approach against ischemic/reperfusion (I/R) injury in cells. The present study mainly centered on discovering the mechanisms of Sevoflurane (Sev) in preventing cardiomyocytes against I/R injury. Human cardiomyocyte AC16 cell line was used to simulate I/R injury based on a hypoxia/reperfusion (H/R) model. After Sev treatment, cell viability and apoptosis were detected by MTT assay and flow cytometry, respectively. Lactate dehydrogenase (LDH) content was measured using an LDH Detection Kit. Relative mRNA and protein expressions of LINC01133, miR-30a-5p and apoptosis-related proteins were detected using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot as needed. Target gene of miR-30a-5p and their potential binding sites were predicted using Starbase and confirmed by dual-luciferase reporter assay. Cell behaviors were assessed again after miR-30a-5p and LINC01133 transfection. Sev could improve cell viability, reduce LDH leakage, and down-regulate the expressions of apoptosis-related proteins (Bax, cleaved caspase-3 and cleaved caspase-9) and LINC01133 as well as up-regulate miR-30a-5p and Bcl-2 expressions in H/R cells. MiR-30a-5p was the target of LINC01133, and up-regulating miR-30a-5p enhanced the effects of Sev in H/R cells, with a suppression on H/R-induced activation of the p53 signaling pathway. However, up-regulating LINC01133 reversed the enhancing effects of miR-30a-5p on Sev pretreatment in H/R cells. Sev could protect cardiomyocytes against H/R injury through the miR-30a-5p/LINC01133 axis, which may provide a possible therapeutic method for curing cardiovascular I/R injury.     

LINC00665 induces gastric cancer progression through activating Wnt signaling pathway

Long noncoding RNAs (lncRNAs) are recently recognized as noteworthy regulators of different tumors, counting gastric cancer (GC). Lately, long intergenic noncoding RNA (LINC) 00665 has been verified to display significant parts in several cancers. Be that as it may, its role and mechanism in GC movement still stay uninvestigated. As of now, we observed LINC00665 was obviously GC cells (MKN28, BGC-823, SGC7-901, AGS, HGC-27) in comparison to GES-1 cells, which was identified as human normal gastric epithelial cells. Then, LINC00665 was obviously downregulated in GC cells including AGS and BGC-823 cells. Loss of LINC00665 greatly repressed AGS and BGC-823 cell survival and cell expansion. Moreover, GC cell apoptosis was significantly induced by the loss of LINC00665. For another, we found that the GC cell cycle was also captured in G1 and G2 phases. The experiments on cell migration and invasion indicated that knockdown of LINC00665 restrained GC cell migration and invasion. Modifications in Wnt signaling are closely associated with the development of cancers. Here, we found that Wnt signaling was significantly inactivated by the silence of LINC00665 in GC cells. β-catenin and cyclinD1 were restrained whereas GSK-3β was induced by the inhibition of LINC00665 in GC cells. Furthermore, we confirmed the impact of LINC00665 in vivo using xenograft models. Taken these together, we indicated that LINC00665 could function as a novel biomarker in GC progression.     

LINC01133 inhibits breast cancer invasion and metastasis by negatively regulating SOX4 expression through EZH2

Mounting evidence highlights long non‐coding RNAs (lncRNAs) as crucial regulators in multiple types of biological processes and contributing to tumourigenesis. LINC01133, located in chromosome 1q23.2, was a recently identified novel lncRNA with a length of 1154nt. It was involved in the development of colorectal cancer and non‐small cell lung cancer. However, its clinical relevance, biological functions and potential molecular mechanism in breast cancer are still unclear. In this study, we found that the LINC01133 expression was significantly down‐regulated in breast cancer samples and was associated with progression and poor prognosis of breast cancer. Further experiments demonstrated that overexpression of LINC01133 inhibited invasion and metastasis in breast cancer both in vitro and in vivo. Mechanistic investigations revealed that LINC01133 repressed SOX4 expression by recruiting EZH2 to SOX4 promoter. Moreover, rescue experiments further confirmed that LINC01133 functional acted as an anti‐oncogene, at least partly, via repressing SOX4 in breast cancer. Taken together, these findings imply that LINC01133 could serve as a novel prognostic biomarker and potential therapeutic target for breast cancer.     

LINC01451 drives epithelial-mesenchymal transition and progression in bladder cancer cells via LIN28/TGF-β/Smad pathway

BackgroundThe pathogenesis of bladder cancer (BLCa) is still unclear. Long non-coding RNAs (lncRNAs) participate in diverse biological processes across every branch of life, especially in cancer. Dysregulated lncRNAs in BLCa and their biological significance require further investigations.MethodsHerein, a differential expression profile of lncRNAs in BLCa was conducted by microarray data. The expression level of lncRNA LINC01451 in 70 pairs of BLCa tissue samples and different BLCa cell lines were analyzed via real-time quantitative PCR. The CRISPR-CAS9 technique was employed to establish the LINC01451 stably transfected cell lines. Loss-of-function, as well as gain-of-function assays were carried out to evaluate the effects of LINC01451 on cell proliferation, migration, and invasion. Patient-derived xenograft (PDX) mouse models were adopted in the in vivo experiments. Western blot, biotinylated RNA probe pull-down assay, fluorescence in situ hybridization, and immunohistochemistry were utilized to assess the underlying molecular mechanisms of LINC01451 in BLCa.ResultsLINC01451 was identified a novel functional lncRNA, whose expression level in BLCa tissues was significantly higher compared with the normal tissues. Furthermore, it was found that LINC01451 directly docked LIN28A and LIN28B, and promoted the proliferation, invasion, and metastasis of BLCa. Mechanistically, LINC0145 was shown to depend on LIN28A and LIN28B, facilitated epithelial-mesenchymal transition (EMT) through activating the TGF-β/Smad signaling pathway, which subsequently aggravated BLCa progression.ConclusionsWe demonstrates that LINC01451 drives EMT-induced BLCa progression by activating the LIN28/TGF-β/Smad signaling pathway. Promisingly, LINC01451 acts as a prognostic biomarker and a novel therapeutic target for BLCa.     

Overexpression of LINC00037 represses cervical cancer progression by activating mTOR signaling pathway

Long non-coding RNAs have been reported to play crucial roles in tumorigenesis including cervical cancer. LINC00037 has been identified as a significant regulator in several cancers. Our study was aimed to investigate the function of LINC00037 in cervical cancer progression. LINC00037 was significantly downregulated in human cervical cancer cells (HeLa, HCC94, HT-3, Caski, and SiHa cells) compared with the ectocervical epithelial cells (End1/E6E7 cells). Overexpression of LINC00037 was able to inhibit cervical cancer cell proliferation, induce cell apoptosis, and restrain the cell migration/invasion capacity. Reversely, knockdown of LINC00037 exhibited an opposite process in vitro. mTOR has been recognized as an atypical serine/threonine kinase that is involved in regulating significant cellular functions. In our present study, we observed that the mTOR signaling pathway was strongly activated in human cervical cancer cells. Meanwhile, upregulation of LINC00037 contributed to the inactivation of mTOR signaling whereas downregulation of LINC00037 activated the pathway. Subsequently, in vivo animal models using SiHa cells were established and we proved that LINC00037 repressed cervical cancer progression via targeting the mTOR signaling pathway. All these findings implied that LINC00037 could regulate cervical cancer pathogenesis via mTOR signaling. In conclusion, a novel role of LINC00037 was manifested in cervical cancer progression.     

Cancer-associated fibroblasts–derived exosomes-mediated transfer of LINC00355 regulates bladder cancer cell proliferation and invasion

The aim of this study was to investigate the regulatory mechanism of cancer-associated fibroblasts (CAFs) exosome in bladder cancer (BC) cell proliferation and invasion. CAFs and normal fibroblasts (NFs) were isolated from tumor tissues and adjacent normal tissues of BC patients, and examined by immunocytochemistry for the expression of fibroblast activation protein alpha (FAP) and α-smooth muscle actin (α-SMA). Exosomes were extracted from CAFs and NFs and observed under a transmission electron microscope, and expression of the exosome markers CD9 and CD63 was confirmed by western blotting. The distribution and intensity of fluorescence were observed by confocal laser microscopy to analyze exosomes uptake by BC cell lines T24 or 5367. BC cell proliferation and invasion were detected by MTT and Transwell assays, respectively. LINC00355 levels in CAFs, NFs, CAFs exosome, NFs exosome, and BC cells were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Results showed that CAFs exosome significantly promoted BC cell proliferation and invasion relative to NFs exosome. LINC00355 expression was significantly elevated in CAFs exosome when compared with that in NFs-exosome. Up-regulated LINC00355 expression was observed both in T24 and 5367 cells co-incubated with CAFs exosome. Exosomes derived from LINC00355 siRNA-transfected CAFs observably repressed BC cell proliferation and invasion when compared with control siRNA-CAFs exosome. In conclusion, CAFs exosome–mediated transfer of LINC00355 regulates BC cell proliferation and invasion. Significance of the study. In this study, our data suggest that the exosomes released from CAFs promote BC cell proliferation and invasion. The mechanism of this effect is, at least in part, related to the increased LINC00355. Regulation of LINC00355 expression in exosomes released from CAFs might be a putative therapeutic strategy against the pathogenesis of BC.     

LINC00461 promotes cell migration and invasion in breast cancer through miR-30a-5p/integrin β3 axis

Mounting evidence has demonstrated that long noncoding RNAs (lncRNAs) are dysregulated and implicated in the occurrence and development of a wide range of human malignancies. LINC00461, a novel cancer-related lncRNA, has been reported to be highly expressed and serve as oncogene in glioma; however, its biological role in breast cancer (BC) remains obscure. This study aimed to explore the role of LINC00461 in BC and elucidate the potential molecular mechanisms involved. In the current study, LINC00461 was found to be significantly upregulated in both BC tissues and cell lines. Besides, we found that high LINC00461 expression was associated with TNM stage and differentiation. Furthermore, functional studies demonstrated that LINC00461 expedited BC cell migration and invasion. Notably, LINC00461 was observed to enhance the expression of vimentin and zinc-finger E-box binding homeobox factor 1, suppress the expression of E-cadherin, and promote the activation of extracellular signal-regulated kinase and AKT signaling pathways. Mechanical investigations revealed that LINC00461 positively modulated integrin β3 (ITGB3) expression as miR-30a-5p sponge in BC cells. Taken together, LINC00461 exerts an oncogenic role in BC through miR-30a-5p/ITGB3 axis. Our data indicate that LINC00461 may be used to be a novel candidate therapeutic target and a valuable diagnostic biomarker for BC.     

Novel splice variants of LINC00963 suppress colorectal cancer cell proliferation via miR-10a/miR-143/miR-217/miR-512-mediated regulation of PI3K/AKT and Wnt/β-catenin signaling pathways

Emerging evidence has shown lncRNAs play important roles in signaling pathways involved in colorectal cancer (CRC) carcinogenesis. However, only a few functional lncRNAs have been extensively researched, especially in CRC-related signaling pathways. Looking for novel candidate regulators of CRC incidence and progression, using available RNA-seq and microarray datasets, LINC00963 was introduced as a bona fide oncogenic-lncRNA. Consistently, RT-qPCR results showed that LINC00963 was up-regulated in CRC tissues. However, our attempt to amplify the full-length lncRNA from cDNA resulted in the discovery of two novel variants (LINC00963-v2 & LINC00963-v3) that surprisingly, were downregulated in CRC tissues, detected by RT-qPCR. Overexpression of LINC00963-v2/-v3 in HCT116 and SW480 cells resulted in downregulation of the major oncogenes and upregulation of the main tumor suppressor genes involved in PI3K and Wnt signaling, verified through RT-qPCR, western blotting, and TOPFlash assays. Mechanistic studies revealed that LINC00963-v2/-v3 exert their effect on PI3K and Wnt signaling through sponging miR-10a-5p, miR-143-3p, miR-217, and miR-512-3p, which in turn these miRNAs are fine-regulators of PTEN, APC1, and Axin1 tumor suppressor genes verified by dual-luciferase assay and RT-qPCR. At cellular levels, LINC00963-v2/-v3 overexpression suppressed cell proliferation, viability, and migration while increasing the apoptosis of CRC cell lines, detected by PI flow cytometry, colony formation, MTT, RT-qPCR, wound-healing, Transwell, AnnexinV-PE/7AAD, caspase3/7 activity assays, and Hoechst/PI-AO/EB staining. Overall, our results indicate that LINC00963-v2 & -v3 are novel tumor suppressor ceRNAs that attenuate the PI3K and Wnt pathways during CRC incidence and these lncRNAs may serve as potential targets for CRC therapy.