LINC00473: A novel oncogenic long noncoding RNA in human cancers.

Long noncoding RNAs (lncRNAs) have been found to play essential roles in the occurrence and development of multiple human cancers. Accumulating evidence has shown that LINC00473, an oncogenic lncRNA, is upregulated in various human malignancies and related to poor clinical outcomes. Besides, LINC00473 overexpression can promote cell proliferation, migration, and invasion through multiple potential mechanisms, indicating that it may serve as a novel prognostic biomarker and therapeutic target for human cancers. Here, we reviewed the biological functions, molecular mechanisms, and clinical implications of LINC00473 in human cancers.

Knockdown of Long Non-coding RNA LINC00473 Protects CHON-001 Cells against Interleukin-1ß-Induced Cell Injury.

Osteoarthritis (OA) is a chronic joint disease with high prevalence. However, effective treatment options for OA are still lacking. It was previously reported that LINC00473 was upregulated in patients with OA and upregulated LINC00473 might be associated with the progression of OA; however, the role of LINC00473 in OA remains to be investigated. CHON-001 human chondrocyte cells stimulated with 10 ng/mL interleukin (IL)-1ß were utilized to mimic OA in vitro. Protein expression, cell apoptosis and cell proliferation of CHON-001 cells were investigated by Western blot, Annexin V and propidium iodide (PI) double staining, cell counting-8 kit assay and immunofluorescence staining respectively. The result indicated IL-1ß triggered viability decrease and apoptosis in CHON-001 cells, which was alleviated by LINC00473 knockdown. Meanwhile, IL-1ß-induced upregulation of cleaved caspase 3 and Bax were ameliorated by LINC00473 knockdown. Likewise, IL-1ß-induced downregulation of X-linked inhibitor of apoptosis protein was alleviated by LINC00473 knockdown. In addition, LINC00473 knockdown protected CHON-001 cells against IL-1ß by inhibiting the methylation of LIM mineralization protein (LMP)-1 gene. Moreover, c-Jun N-terminal kinase (JNK)/nuclear factor-kappaB (NF-κB) signaling pathway was proved to be involved in the cell protective effect of LINC00473 knockdown in IL-1ß treated CHON-001 cells. Taken together, LINC00473 knockdown defended CHON-001 cells from IL-1ß induced cell injury via inhibition of the methylation of LMP-1. Thus, LINC00473 might possibly act as a novel therapeutic target for OA.

LINC00473 protects against cerebral ischemia reperfusion injury via sponging miR-15b-5p and miR-15a-5p to regulate SRPK1 expression.

BACKGROUND: Cerebral ischemia is associated with a high burden of neurological disability. Recently, emerging evidence has demonstrated that long non-coding RNAs (lncRNAs) are crucial regulators in cerebral ischemia reperfusion (I/R) injury. Herein, we investigated the function and potential mechanism of long intergenic non-protein coding RNA 473 (LINC00473) in cerebral I/R injury. METHODS: We established oxygen glucose deprivation/reperfusion (OGD/R) model in Neuro-2a (N2a) cells to mimic the cerebral I/R injury in vitro. RT-qPCR and Western blot assays were conducted to detect target gene expression. Functional assays measured the effects of LINC00473 on cell viability, apoptosis and reactive oxygen species (ROS) production. A series of mechanism assays were carried out to detect the potential mechanism of LINC00473 in cerebral I/R injury. RESULTS: LINC00473 was significantly down-regulated in OGD/R-induced injury model. LINC00473 overexpression reversed the reduced cell viability as well as the enhanced apoptosis and ROS level induced by OGD/R. Moreover, LINC00473 functioneds as a competing endogenous RNA (ceRNA) to sponge miR-15b-5p and miR-15a-5p and thereby regulated SRSF protein kinase 1 (SRPK1) expression. CONCLUSIONS: Our findings confirmed the protective role of LINC00473 in cerebral I/R injury, which might provide a novel target for treating ischemic brain injury.

LINC00473 downregulation facilitates trophoblast cell migration and invasion via the miR-15a-5p/LITAF axis in pre-eclampsia.

More and more evidence has identified that long non-coding RNAs (lncRNAs) are involved in various biological process of numerous diseases. It has been reported that long intergenic non-protein coding RNA 473 (LINC00473) was associated with pre-eclampsia (PE) development. However, role and molecular mechanism of LINC00473 in PE remains elusive. Therefore, we designed this research to figure out the specific biological function of LINC00473 in trophoblasts. Firstly, we testified expressions of LINC00473 in trophoblasts of PE with RT-qPCR analysis. Then, to probe biological function of LINC00473 in trophoblasts of PE, CCK-8 assay, trans-well assays and western blot analysis were conducted in Wish and JAR cells. As for verifying interaction of microRNA-15a-5p (miR-15a-5p) and LINC00473 or lipopolysaccharide induced TNF factor (LITAF), RNA pull-down and luciferase reporter assays were carried out. Finally, rescue experiments were conducted to probe regulatory pattern of the LINC00473/miR-15a-5p/LITAF axis in trophoblasts of PE. As a result, LINC00473 presented a significant upregulation in trophoblasts of PE. Moreover, LINC00473 knockdown induced trophoblast viability, migration, invasion, and epithelial-to-mesenchymal transition (EMT) in trophoblasts. Additionally, miR-15a-5p interacted with LINC00473 and miR-15a-5p was negatively regulated by LINC00473 in trophoblasts. Simultaneously, miR-15a-5p negatively modulated LITAF in trophoblasts. Moreover, LITAF overexpression or miR-15a-5p downregulation reversed the promotive impact of silenced LINC00473 on trophoblast viability, migration, invasion and EMT. In conclusion, LINC00473 regulated migration and invasion in trophoblasts via the miR-15a-5p/LITAF axis. Our study may provide a novel insight for clinical treatment of PE.

Linc00473 potentiates cholangiocarcinoma progression by modulation of DDX5 expression via miR-506 regulation.

BACKGROUND: Cholangiocarcinoma (CCA) is a mortal cancer with high mortality, whereas the function and mechanism of occurrence and progression of CCA are still mysterious. Long non-coding RNAs (lncRNAs) could function as important regulators in carcinogenesis and cancer progression. Growing evidences have indicated that the novel lncRNA linc00473 plays an important role in cancer progression and metastasis. However, its function and molecular mechanism in CCA remain unknown. METHODS: The linc00473 expression in CCA tissues and cell lines was analyzed using qRT-PCR. Gain- and loss-of-function experiments were conducted to investigate the biological functions of linc00473 both in vitro and in vivo. Insights into the underlying mechanisms of competitive endogenous RNAs (ceRNAs) were determined by bioinformatics analysis, dual-luciferase reporter assays, qRT-PCR arrays, RNA immunoprecipitation (RIP) and rescue experiments. RESULTS: Linc00473 was highly expressed in CCA tissues and cell lines. Linc00473 knockdown inhibited CCA growth and metastasis. Furthermore, linc00473 acted as miR-506 sponge and regulated its target gene DDX5 expression. Rescue assays verified that linc00473 modulated the tumorigenesis of CCA by regulating miR-506. CONCLUSIONS: The data indicated that linc00473 played an oncogenic role in CCA growth and metastasis, and could serve as a novel molecular target for treating CCA.

LINC00473 promotes lung adenocarcinoma progression by regulating miR-1294/ROBO1 axis.

Long noncoding RNA (lncRNA) LINC00473 has been reported to be involved in the regulation of several human cancers. However, the regulatory mechanism of LINC00473 is still unknown in lung adenocarcinoma. In this study, RT-qPCR was used to measure the expression of LINC00473, miR-1294 and ROBO1. The functional mechanism of the LINC00473/miR-1294/ROBO1 pathway was investigated by CCK-8, Transwell and dual luciferase reporter assays. The results showed that LINC00473 was up-regulated and miR-1294 was down-regulated in lung adenocarcinoma tissues and cells. LINC00473 can bind to miR-1294, and reciprocal inhibition between LINC00473 and miR-1294 expression was identified in lung adenocarcinoma. Functionally, LINC00473 promoted cell proliferation and motility in lung adenocarcinoma by downregulating miR-1294. In addition, miR-1294 directly targets ROBO1. ROBO1 served as an oncogene in lung adenocarcinoma. In particular, LINC00473 promoted the progression of lung adenocarcinoma by upregulating ROBO1. In conclusion, LINC00473 acts as a tumor promoter in lung adenocarcinoma by regulating the miR-1294/ROBO1 axis.

Long noncoding RNA LINC00473 drives the progression of pancreatic cancer via upregulating programmed death-ligand 1 by sponging microRNA-195-5p.

Pancreatic cancer (PC) is a great health burden to patients owing to its poor overall survival rate. Long noncoding RNAs (lncRNAs) interact with microRNAs (miRs) to participate in tumorigenesis. Therefore, we aim to uncover the role and related mechanism of LINC00473 in PC through the modulation of miR-195-5p and programmed death-ligand 1 (PD-L1). Increased LINC00473 and PD-L1 but declined miR-195-5p were determined in PC tissues and cell lines, and it was found that LINC00473 mainly situated in the cytoplasm. Also, miR-195-5p was verified to bind with both LINC00473 and PD-L1. Next, with the aim to examine the ability of LINC00473, miR-195-5p, and PD-L1 on the PC progression, the expression of LINC00473, miR-195-5p and PD-L1 were altered with mimics, inhibitors, overexpression vectors or siRNAs in PC cells and cocultured CD8+ T cells. It was demonstrated that LINC00473 sponged miR-195-5p to upregulate PD-L1 expression. More important, the obtained results revealed that LINC00473 silencing or miR-195-5p upregulation elevated the expression of Bcl-2 associated X protein (Bax), interferon (IFN)-γ, and interleukin (IL)-4 but reduced the expression of B-cell lymphoma-2 (Bcl-2), matrix metalloproteinase (MMP)-2, MMP-9, and IL-10, thus inducing the enhancement of the apoptosis as along with the inhibition of proliferation, invasion, and migration of the PC cells. LINC00473 silencing or miR-195-5p elevation activated the CD8+ T cells. Taken together, LINC00473 silencing blocked the PC progression through enhancing miR-195-5p-targeted downregulation of PD-L1. This finding offers new therapeutic options for treating this devastating disease.

LINC00473/miR-374a-5p regulates esophageal squamous cell carcinoma via targeting SPIN1 to weaken the effect of radiotherapy.

Esophageal squamous cell carcinoma (ESCC) is the most prevalent type in esophageal cancers. Despite accumulating achievements in treatments of ESCC, patients still suffer from recurrence because of the treatment failures, one of the reasons for which is radioresistance. Therefore, it is a necessity to explore the molecular mechanism underlying ESCC radioresistance. Long intergenic noncoding RNA 473 (LINC00473) has been reported to be aberrantly expressed in several human malignancies. However, its biological function in radiosensitivity of ESCC remains to be fully understood. This study explored the role of LINC00473 in radiosensitivity of ESCC cells and whether LINC00473 acted as a competing endogenous RNA to realize its modulation on radioresistance. We found that LINC00473 was markedly upregulated in ESCC tissues and cell lines, and its expression was remarkably related to cellular response to irradiation. In addition, knockdown of LINC00473 could sensitize ESCC cells to radiation in vitro. As for the underlying mechanism, we uncovered that there was a mutual inhibition between LINC00473 and miR-374a-5p. Spindlin1 (SPIN1) was verified as a downstream target of miR-374a-5p, and LINC00473 upregulated SPIN1 expression through negatively modulating miR-374a-5p expression. Furthermore, we revealed that SPIN1 could aggravate the radioresistance of ESCC cells. Finally, overexpression of SPIN1 reversed the LINC00473 silencing-enhanced radiosensitivity in ESCC cells. To sum up, we demonstrated that LINC00473 facilitated radioresistance by regulating the miR-374a-5p/SPIN1 axis in ESCC.

The placental blood perfusion and LINC00473-mediated promotion of trophoblast apoptosis in fetal growth restriction.

This study aimed to investigate placental microblood flow perfusion in fetal growth restriction (FGR) both pre- and post-delivery, and explore the influence of LINC00473 and its downstream targets on FGR progression in trophoblast cells. Placental vascular distribution, placental vascular index (VIMV), CD34 expression, and histological changes were compared between control and FGR groups. FGR-related differentially expressed genes (DEGs) were analyzed and validated by quantitative real-time polymerase chain reaction (qPCR) and immunohistochemistry (IHC) in placentae. In vitro experiments examined the regulatory relationships among LINC00473, miR-5189-5p, and StAR, followed by investigations into their impacts on cell proliferation and apoptosis. FGR placentae exhibited irregular shapes, uneven parenchymal echo, stromal dysplasia, ischemic infarction, and variable degrees of thickening in some cases. FGR samples showed less prominent mother vessel lakes, significantly lower VIMV, and decreased CD34 expression. Hematoxylin & eosin (H&E) staining revealed placental fibrosis, fibrin adhesion, infarction, and interstitial dysplasia in FGR. LINC00473, miR-5189-5p, and StAR were identified as DEG, with qPCR demonstrating a significant increase in LINC00473 and a decrease in miR-5189-5p in FGR, while both qPCR and IHC indicated a significant increase in StAR expression. LINC00473 served as an endogenous sponge against miR-5189-5p in human HTR-8/SV neo cells, and StAR expression was regulated by both LINC00473 and miR-5189-5p. Dysregulation of these genes affected cell proliferation and apoptosis. Pathological changes in the placenta are significant contributors to FGR, with placental microblood flow potentially serving as an indicator for monitoring its progression. LINC00473 and its downstream targets may modulate trophoblasts proliferation and apoptosis, thus influencing the onset of FGR, suggesting novel avenues for diagnosis and treatment.

Long Non-coding RNA LINC00473 Promotes Breast Cancer Progression via miR-424-5p/CCNE1 Pathway.

BACKGROUND: There has been a large increase in the incidence of breast cancer (BC) among women. LINC00473 is a cancer-related lncRNA, participating in the progression of many cancers, but its role in the progression of BC awaits more elaboration. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) was used to quantify LINC00473, miR-424-5p, and cyclin E1 (CCNE1) mRNA expression levels in BC tissues and cells. Cell counting kit-8 (CCK-8) assay was employed to detect the cell viability; the cell migration and invasion abilities were evaluated by the Transwell assay. Western blot and immunohistochemistry (IHC) were adopted to study CCNE1 protein expression; dual-luciferase reporter assay was performed to clarify the targeting relationships among LINC00473, miR-424-5p, and CCNE1. RESULTS: LINC00473 expression was elevated in BC tissues and cell lines, which was associated with lymph node metastasis and higher clinical stage of the patients with BC. LINC00473 proved to be a molecular sponge for miR-424-5p; LINC00473 knockdown impeded the growth, migration, invasion, and epithelial-mesenchymal transition of BC cells, while these effects were abolished by miR-424-5p inhibitors; miR-424-5p targeted CCNE1 to restrain its expression. LINC00473 positively regulated CCNE1 expression, and CCNE1 restoration counteracted the effects induced by LINC00473 knockdown in BC cells. CONCLUSION: LINC00473 facilitates the progression of BC through miR-424-5p/CCNE1 axis.

Noninvasive early detection of colorectal cancer by hypermethylation of the LINC00473 promoter in plasma cell-free DNA.

BACKGROUND: Current noninvasive assays have limitations in the early detection of colorectal cancer. We evaluated the clinical utility of promoter methylation of the long noncoding RNA LINC00473 as a noninvasive biomarker to detect colorectal cancer and associated precancerous lesions. METHODS: We evaluated the epigenetic regulation of LINC00473 through promoter hypermethylation in colorectal cancer cell lines using bisulfite genomic sequencing and expression analyses. DNA methylation of LINC00473 was analyzed in primary colorectal tumors using 450K arrays and RNA-seq from The Cancer Genome Atlas (TCGA). Tissue-based findings were validated in several independent cohorts of colorectal cancer and advanced colorectal polyp patients by pyrosequencing. We explored the clinical utility of LINC00473 methylation for the early detection of colorectal cancer in plasma cell-free DNA by quantitative methylation-specific PCR and droplet digital PCR. RESULTS: LINC00473 showed transcriptionally silencing due to promoter hypermethylation in colorectal cancer cell lines and primary tumors. Methylation of the LINC00473 promoter accurately detected primary colorectal tumors in two independent clinical cohorts, with areas under the receiver operating characteristic curves (AUCs) of 0.94 and 0.89. This biomarker also identified advanced colorectal polyps from two other tissue-based clinical cohorts with high diagnostic accuracy (AUCs of 0.99 and 0.78). Finally, methylation analysis of the LINC00473 promoter in plasma cell-free DNA accurately identified patients with colorectal cancer and advanced colorectal polyps (AUCs of 0.88 and 0.84, respectively), which was confirmed in an independent cohort of patients. CONCLUSIONS: Hypermethylation of the LINC00473 promoter is a new promising biomarker for noninvasive early detection of colorectal cancer and related precancerous lesions.

LINC00473-modified bone marrow mesenchymal stem cells incorporated thermosensitive PLGA hydrogel transplantation for steroid-induced osteonecrosis of femoral head: A detailed mechanistic study and validity evaluation.

The pathogenesis of steroid-induced osteonecrosis of the femoral head (SONFH) involves a glucocorticoid-induced imbalance of osteogenic and adipogenic differentiation, and apoptosis of bone marrow mesenchymal stem cells (BMSCs). An increasing number of genes, especially noncoding RNAs, have been implicated in the function of BMSCs. Our previous studies have confirmed the key role of LINC00473 and miR-23a-3p on the osteogenic, adipogenic differentiation, and apoptosis of BMSCs. However, the underlying mechanism of this process is still unclear. Based on bioinformatics analysis, here we investigated the effects of LINC00473 on the LRP5/Wnt/ß-catenin signaling pathway in the osteogenesis and adipogenesis of BMSCs, as well as the PEBP1/Akt/Bad/Bcl-2 signaling pathway in dexamethasone- (Dex-) induced apoptosis of BMSCs. Our data showed that LINC00473 could promote osteogenesis and suppress the adipogenesis of BMSCs through the activation of the miR-23a-3p/LRP5/Wnt/ß-catenin signaling pathway axis, while rescuing BMSCs from Dex-induced apoptosis by activating the miR-23a-3p/PEBP1/Akt/Bad/Bcl-2 signaling pathway axis. Notably, we observed that LINC00473 interacted with miR-23a-3p in an Argonaute 2 (AGO2)-dependent manner based on dual-luciferase reporter assay, AGO2-related RNA immunoprecipitation, and RNA antisense purification assay. Furthermore, injectable thermosensitive polylactic-co-glycolic acid (PLGA) hydrogel loaded with rat-derived BMSCs (rBMSCs) modified by LINC00473 were used for the treatment of SONFH in a rat model. Our results demonstrated that PLGA hydrogels provided a suitable environment for harboring rBMSCs. Besides, transplantation of PLGA hydrogels loaded with rBMSCs modified by LINC00473 could significantly promote the bone repair and reconstruction of the necrotic area at the femoral head in our SONFH rat model. Surprisingly, compared with the transplantation of BMSCs alone, the transplanted rBMSCs encapsulated within the PLGA hydrogel could migrate from the medullary cavity to the femoral head. In summary, LINC00473 promoted osteogenesis, inhibited adipogenesis, and antagonized Dex-induced apoptosis of BMSCs. Therefore, LINC00473 could provide a new strategy for the treatment of SONFH.

LncRNA LINC00473 promoted colorectal cancer cell proliferation and invasion by targeting miR-195 expression.

Long noncoding RNAs (lncRNAs) have been shown to play crucial roles in cancer development. However, the role of LINC00473 in colorectal cancer has not been explored. In our study, we showed that LINC00473 expression was upregulated in colorectal cancer samples compared to nontumor samples. The expression of LINC00473 in colorectal cancer tissues from patients with distant metastasis was higher than that from cases without distant metastasis. The higher expression level of LINC00473 was positively correlated with advanced clinical stage. The elevated expression of LINC00473 accelerated colorectal cancer cell proliferation, cell cycle progression and invasion. Moreover, overexpression of LINC00473 induced epithelial to mesenchymal (EMT) progression in HT29 and SW480 cells. Ectopic expression of LINC00473 suppressed miR-195 expression in colorectal cancer cells. miR-195 expression was downregulated in colorectal cancer samples compared with nontumor samples. The expression of miR-195 in colorectal cancer tissues from patients with distant metastasis was lower than that from cases without distant metastasis. The lower expression level of miR-195 was positively correlated with advanced clinical stage. In addition, we showed that the expression of miR-195 was negatively correlated with the LINC00473 expression level in colorectal cancer tissues. LINC00473 accelerated colorectal cancer cell proliferation and cell cycle progression and regulated EMT progression by regulating miR-195 expression. These data suggested that LINC00473 induced cell proliferation, cell cycle progression and EMT progression by acting as a ceRNA for miR-195 in colorectal cancer.

Long intergenic ncRNA 00473 improves the invasion of trophoblastic cells via miR-16-5p.

Preeclampsia (PE) is a common disease among pregnant women and is characterized by high blood pressure, edemas, proteinuria, etc. However, the underlying mechanism of PE is still not clear. Our results may provide a new understanding of the pathogenesis of PE and a therapeutical target for the treatment of the disease. Levels of long intergenic ncRNA 00473 (LINC00473), miR-16-5p, MMP2, MMP9, Bcl-2, Bax, and C caspase-3 in placental tissues or human trophoblastic cells were assessed. HTR8/SVneo and JEG-3 cells were transfected with LINC00473, miR-16-5p mimic, LINC00473 siRNA, or miR-16-5p inhibitor alone, or co-transfected with LINC00473 and miR-16-5p mimic or LINC00473 siRNA and miR-16-5p inhibitor. Viability, apoptosis, migration and invasion of cells were assessed by Cell Counting Kit-8, flow cytometry, wound healing assay and Transwell assay, respectively. The target gene of LINC00473 was analyzed using Starbase and dual-luciferase reporter assay. LINC00473 level was down-regulated in placental tissues of PE patients. LINC00473 overexpression increased cell viability, migration, invasion, and MMP2, MMP9 and Bcl-2 levels, yet decreased the apoptosis rates and Bax and C caspase-3 levels in cells; however, LINC00473 silencing had the opposite effect. LINC00473 targeted miR-16-5p and miR-16-5p level was negatively related to LINC00473 level. MiR-16-5p mimic reversed the promoting effect of LINC00473 overexpression on the invasion of HTR8/SVneo and JEG-3 cells, while miR-16-5p inhibitor reversed the inhibitory effect of LINC00473 silencing on the invasion of these cells. In conclusion, LINC00473 improved the invasion of human trophoblastic cells via miR-16-5p.

lncRNA LINC00473 promotes proliferation, migration, invasion and inhibition of apoptosis of non-small cell lung cancer cells by acting as a sponge of miR-497-5p.

Lung cancer is the leading cause of cancer-associated death worldwide and exhibits a poor prognosis. The present study aimed to determine the effect of long non-coding (lnc)RNA-LINC00473 on the development of non-small cell lung cancer (NSCLC) cells by regulating the expression of microRNA (miR)-497-5p. Reverse transcription-quantitative PCR was conducted to detect the level of LINC00473 and miR-497-5p. An MTT assay, flow cytometry and Transwell tests were performed to evaluate the proliferation, apoptosis, migration and invasion of NSCLC cells. Western blotting was performed to detect the expression of apoptosis- and migration-related proteins. RNA immunoprecipitation and a luciferase reporter assay were performed to verify the regulatory relationship between lncRNA-LINC00473 and miR-497-5p. LINC00473 expression was upregulated in lung cancer tissues and NSCLC cells (A549 and H1299) when compared with adjacent tissues or human bronchial epithelial cell lines and the 5-year survival rate was lower in patients with high LINC00473 expression compared with in patients with low LINC00473 expression. A negative correlation between LINC00473 and miR-497-5p was observed in lung cancer tissues. Proliferation, migration and invasion as well as the related protein levels were increased in A549 and H1299 transfected with pcDNA3.1-LINC00473, while the opposite results were obtained in A549 and H1299 transfected with small interfering (si)-LINC00473. Notably, it was demonstrated that LINC00473 could bind directly with miR-497-5p and inhibit its expression. miR-497-5p inhibitors reversed the effect of si-LINC00473. Furthermore, the present study demonstrated that LINC00473 promoted the malignant behaviour of NSCLC cells via regulating the ERK/p38 and MAPK signalling pathways and the expression of miR-497-5p.

LINC00473 rescues human bone marrow mesenchymal stem cells from apoptosis induced by dexamethasone through the PEBP1­mediated Akt/Bad/Bcl­2 signaling pathway.

The inhibition of the proliferation and apoptosis of bone marrow­derived mesenchymal stem cells (BMSCs) triggered by the excessive use of glucocorticoids, is considered a potential mechanism for the pathogenesis of steroid­induced osteonecrosis of the femoral head (SONFH). Long non­coding RNAs (lncRNAs) have been proven to influence the proliferation, apoptosis and differentiation of BMSCs by regulating the expression of critical genes. A previous microarray analysis by the authors confirmed the significant downregulation of LINC00473 in human BMSCs (hBMSCs) from patients with SONFH. However, the underlying role and molecular mechanisms of LINC00473 on dexamethasone (Dex)­stimulated hBMSCs remains unknown. In the present study, the expression of LINC00473 was determined in the hBMSCs of patients with SONFH and control patients. In addition, the protective effects and underlying molecular mechanisms of LINC00473 in Dex­stimulated hBMSCs were investigated. The results revealed that LINC00473 expression was significantly downregulated in hBMSCs from patients with SONFH compared with the controls, and that the upregulation of LINC00473 attenuated the inhibitory effects exerted by 1 µM Dex on the proliferation and apoptosis of hBMSCs. Moreover, the upregulation of LINC00473 significantly promoted the protein expression of phosphorylated (p­)Akt, p­Bcl­2­associated death promoter (p­Bad) and B­cell lymphoma 2 (Bcl­2), whereas it decreased the cleavage of caspase­3, thus preventing the Dex­induced apoptosis of hBMSCs. Of note, the regulatory effects of LINC00473 on the Akt/Bad/Bcl­2 signaling pathway and its anti­apoptotic effects were similar to those of SC79 (an Akt activator), and were inhibited by MK­2206 (an Akt inhibitor). In further experiments, it was found that the upregulation of LINC00473 markedly promoted the phosphorylation of Akt in Dex­stimulated hBMSCs, and increased the protein level of phosphatidylethanolamine­binding protein 1 (PEBP1). Alternatively, the promoting effect on Akt phosphorylation induced by LINC00473 was significantly attenuated following the knockdown of PEBP1. Furthermore, the upregulation of PEBP1 triggered a marked increase in the levels of Akt phosphorylation in Dex­stimulated hBMSCs, which was line with the upregulation of LINC00473. Taken together, the results of the present study demonstrate that LINC00473 has the ability to rescue hBMSCs from Dex­induced apoptosis through the PEBP1­mediated activation of the Akt/Bad/Bcl­2 signaling pathway.

Knockdown of LINC00473 promotes radiosensitivity of non-small cell lung cancer cells via sponging miR-513a-3p.

Non-small cell lung cancer (NSCLC) is the most common form of lung cancer. Radioresistance is a significant obstacle in NSCLC radiotherapy. Long non-coding RNA LINC00473 has been found to impact the radiotherapy in several malignant tumours. This study aimed to investigate the underlying role and mechanism of LINC00473 in regulating radiosensitivity of NSCLC cells. The levels of LINC00473 and miR-513a-3p were measured by quantitative Real-Time PCR. The relationship of LINC00473 with overall survival was tested by the Kaplan-Meier method. The effects of LINC00473 on cell viability and cell survival were assessed by cell counting kit-8 (CCK-8) and colony survival assay in NSCLC cells exposed to different doses of radiation. A luciferase reporter assay was used to investigate the correlation between LINC00473 and miR-513a-3p. The present study showed that the relative LINC00473 expression was upregulated and miR-513a-3p expression was downregulated in radioresistant NSCLC patients compared with radiosensitive patients. And upregulated LINC00473 expression was associated with poor prognosis of NSCLC patients after radiotherapy. Radiation led to an increase in LINC00473 expression in a dose- and time-dependent manner. The knockdown of LINC00473 markedly promoted radiosensitivity in NSCLC cells under different doses of radiation. LINC00473 was a sponge of miR-513a-3p and negatively regulated the miR-513a-3p expression. In conclusion, the inhibition of miR-513a-3p markedly reversed the promoted effect of LINC00473 knockdown on cell radiosensitivity. LINC00473 inhibition enhances radiosensitivity of NSCLC by sponging miR-513a-3p, providing a promising therapeutic target to increase the sensitivity of radiotherapy in NSCLC patients.

LINC00473 regulated apoptosis, proliferation and migration but could not reverse cell cycle arrest of human bone marrow mesenchymal stem cells induced by a high-dosage of dexamethasone.

Dysfunction of bone marrow mesenchymal stem cells (BMSCs) is involved in the pathogenesis of steroid-induced osteonecrosis of the femoral head (SONFH). Long noncoding RNAs (lncRNAs) contribute to biological effects exerted on BMSCs by regulating the expression of genes. However, most recent studies have focused on the role of lncRNAs in modulating the imbalance between osteogenic and adipogenic differentiation but not apoptosis, proliferation, cell cycle and migration of BMSCs, especially in Dex-treated BMSCs. In this study, we conducted a microarray analysis to investigate the differential expression profiles of lncRNAs between human BMSCs (hBMSCs) obtained from patients with SONFH and control patients with femoral neck fracture. The microarray analysis showed that a total of 48 differentially expressed lncRNAs were identified in hBMSCs between the two groups, including 24 upregulated lncRNAs and 24 downregulated lncRNAs. Among of them, LINC00473 was found to be significantly downregulated. In the following study, we found that 10-6 mol/L Dex significantly inhibited proliferation, arrested cell cycle at the G1 phase, increased caspase-3 activity, induced apoptosis and impeded the migration of hBMSCs, while downregulation of the expression of LINC00473 produced results that were in line with the results of the microarray analysis in a time-dependent manner. Interestingly, upregulation of LINC00473 attenuated the negative effects caused by 10-6 mol/L Dex on hBMSCs, except for cell cycle arrest. Furthermore, it should be noted that LINC00473 had no effect on the proliferation and cell cycle of hBMSCs in the absence of Dex. Collectively, our data revealed that LINC00473 attenuated apoptosis, promoted the proliferation and migration of Dex-induced hBMSCs, which are not involved in interference with the cell cycle of hBMSCs.

Knockdown of LINC00473 Enhances Radiosensitivity in Hepatocellular Carcinoma via Regulating the miR-345-5p/FOXP1 Axis.

BACKGROUND: Hepatocellular carcinoma (HCC) is the most common form of liver cancer. Radioresistance is a significant obstacle in HCC therapy. Long non-coding RNA 473 (LINC00473) has been found to impair the effect of radiotherapy. This study aimed to explore the function and molecular basis of LINC00473 in the radiosensitivity of HCC cells. METHODS: The levels of LINC00473, miR-345-5p and Forkhead Box P1 (FOXP1) were determined by quantitative real-time polymerase chain reaction. Cell viability was assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Survival fraction was calculated by colony survival assay after exposure to different doses of radiation. Cell apoptosis was evaluated by flow cytometry. The interaction among LINC00473, miR-345-5p and FOXP1 was confirmed by dual-luciferase reporter assay. The protein level of FOXP1 was detected by Western blot assay. RESULTS: LINC00473 and FOXP1 were up-regulated, while miR-345-5p was down-regulated in HCC tissues and cells. Radiation elevated LINC00473 expression in a dose- and time-dependent manner. Depletion of LINC00473 inhibited proliferation and heightened radiosensitivity and apoptosis in HCC cells. In addition, LINC00473 was a sponge of miR-345-5p. Also, miR-345-5p overexpression sensitized HCC cells to radiation. Moreover, miR-345-5p directly targeted FOXP1. MiR-345-5p inhibition or FOXP1 up-regulation reversed the enhanced radiosensitivity caused by LINC00473 knockdown. CONCLUSION: LINC00473 contributed to radioresistance in HCC via modulating the miR-345-5p/FOXP1 axis, which might provide a promising diagnostic marker for HCC radiotherapy.

LINC00473 inhibits vascular smooth muscle cell viability to promote aneurysm formation via miR-212-5p/BASP1 axis.

Abdominal aortic aneurysm (AAA), as the most common type of aortic aneurysm, is closely related to the proliferation and apoptosis ability of vascular smooth muscle cells (VSMCs). Long non-coding RNAs (lncRNAs) are emerging regulators in disease development. LncRNA LINC00473 has been shown to affect cell proliferation and apoptosis in various cancers, but its role in AAA is still blank. In this work, in vitro AAA models were successfully established since cell viability was inhibited whereas apoptosis stimulated in VSMCs treated with H2O2. LINC00473 was up-regulated in VSMCs after H2O2 treatment. Overexpression of LINC00473 inhibited VSMC cell proliferation and promoted cell apoptosis and its silence mitigated H2O2-induced injuries to VSMCs. Additionally, we uncovered that LINC00473 sponged miR-212-5p to regulate brain acid soluble protein 1 (BASP1) expression. Finally, rescue assays uncovered that overexpression of miR-212-5p or suppression of BASP1 reversed the effects of LINC00473 up-regulation on cell proliferation and cell apoptosis. And the positive correlation between LINC00473 and BASP1 as well as the negative relation of miR-212-5p to both LINC00473 and BASP1 were confirmed in AAA tissues. All finding illuminated that LINC00473 participated in AAA development by regulating miR-212-5p/BASP1 pathway, suggesting LINC00473 as a promising target for AAA therapy.