[MIR503HG promotes esophageal squamous cell carcinoma cell proliferation, invasion and migration via hsa-miR-503 pathway].

Objective: To explore the function and mechanism of long non-coding RNA MIR503HG in esophageal squamous cell carcinoma (ESCC). Methods: The MIR503HG expression data in 60, 119 and 23 cases of ESCC and their paired adjacent tissues were chosen from three ESCC datasets GSE53622, GSE53624 and GSE130078, respectively. The expression data of MIR503HG in 81 ESCC tissues and 271 unpaired normal esophageal tissues were screened from the combined dataset of Cancer Genome Atlas and Genotype-Tissue Expression Database (TCGA+ GTEx). The MIR503HG knockdown plasmid was constructed, packaged into lentivirus. The lentivirus was used to infect with esophageal squamous cell carcinoma cell lines KYSE30 and KYSE510 to screen out the stable MIR503HG knockdown cell lines. ESCC cell line KYSE30 was transiently transfected with miRNA mimics to overexpress hsa-miR-503-3p and hsa-miR-503-5p.The expression levels of MIR503HG, hsa-miR-503-3p and hsa-miR-503-5p were detected by quantitative real-time polymerase chain reaction. The proliferation ability of the cells was detected by cell counting kit 8 and clone formation assay. The invasion and migration ability of the cells were detected by Transwell assay. Cell cycle was detected by flow cytometry. The effect of MIR503HG on the proliferation of ESCC was detected by xenograft experiment in BALB/c-nu/nu mice. Results: Both GEO and TCGA+ GTEx databases showed that the expression of MIR503HG in ESCC tissues was higher than that in adjacent tissues and normal esophageal tissues (P<0.01). Compared with shNC group, the proliferation rates of KYSE30 and KYSE510 cells after knockdown of MIR503HGwere significantly inhibited (P<0.001). The colony formation numbers of KYSE30 cells in shMIR503HG1 group and shMIR503HG2 group were (2.00±1.41) and (1.33±0.47), respectively, significantly lower than that of the shNC group (P=0.002). The clone formation numbers of KYSE510 cells in shMIR503HG1 group and shMIR503HG2 group were (174.67±15.97) and (80.33±6.34), respectively, significantly lower than that of the shNC group (P<0.001). The invasive numbers of KYSE30 cells in shMIR503HG1 group and shMIR503HG2 group were 75.33±6.02 and 45.67±7.59, significantly lower than that of the shNC group(P<0.001). The migrating number of KYSE30 cells in shMIR503HG1 group and shMIR503HG2 group were 244.00±10.23 and 210.67±13.52, significantly lower than that of the shNC group(P<0.001), and the cell cycle was arrested in G(0)/G(1) phase. The xenograft experiment showed that the subcutaneous tumor in shMIR503HG group was significantly smaller than that in shNC group, and the tumor weight in shMIR503HG group was (0.097±0.026) g, which was lower than (0.166±0.021) g in shNC group (P<0.001). After knockdown of MIR503HG, the relative expression levels of hsa-miR-503-3p in KYSE30 cells of shMIR503HG1 group and shMIR503HG2 group were 0.66±0.02 and 0.58±0.00, respectively, the relative expression levels of hsa-miR-503-5p were 0.64±0.00 and 0.68±0.03, respectively, which were all lower than those in shNC group (P<0.01). After knockdown of MIR503HG, overexpression of hsa-miR-503-3p and hsa-miR-503-5p attenuated the inhibitory effects of knockdown of MIR503HG on proliferation (P<0.001), invasion (P<0.01) and migration (P<0.001) of KYSE30 cells. Conclusions: MIR503HG promotes the proliferation, invasion and migration of ESCC cells by regulating hsa-miR-503 pathway and can be used as a new potential target for targeted therapy of ESCC.

LncRNA MIR503HG promotes hypertrophic scar progression via miR-143-3p-mediated Smad3 expression.

Hypertrophic scars (HSs) form due to unchecked proliferation of fibrous tissue after an injury to the skin. Recently, lncRNA MIR503HG was shown to be involved in HS. However, the mechanism by which MIR503HG affects the formation and progression of HS still needs further study. qRT-PCR was applied to examine the levels of MIR503HG and miR-143-3p in HS tissues and human hypertrophic scar fibroblasts (hHSFs). The relationships of MIR503HG, miR-143-3p and Smad3 were explored with a dual-luciferase reporter assay. Cell proliferation, apoptosis, and invasion were measured by CCK-8 assay, flow cytometry and transwell assay, respectively. The protein level of Smad3 was tested via Western blotting. MIR503HG was upregulated and miR-143-3p was downregulated in HS versus normal skin tissues. The knockdown of MIR503HG and the overexpression of miR-143-3p suppressed the proliferation and invasion of hHSF, and promoted cell apoptosis. MIR503HG bound to miR-143-3p while miR-143-3p directly targeted Smad3 to inhibit its expression. Suppression of miR-143-3p and overexpression of Smad3, respectively, reversed these effects of knockdown of MIR503HG and overexpression of miR-143-3p on hHSFs. Our research supports a model in which the MIR503HG/miR-143-3p/Smad3 axis serves as a critical regulator of HS, highlighting a promising therapeutic option for HS.

Long non-coding RNA MIR503HG inhibits the proliferation, migration and invasion of colon cancer cells via miR-107/Par4 axis.

PURPOSE: Colon cancer is a common caner with high death rate in the world. The study aimed to detect the effect and mechanism of long non-coding RNA (LncRNA) MIR503HG on colon cancer. METHODS: The MIR503HG expression was measured in colon cancer tissues and cell lines by qRT-PCR. The proliferation, apoptosis, migration and invasion of colon cancer cells were measured by MTT, flow-cytometry, wound healing and transwell assay. The protein expression of E-cadherin, N-cadherin, and Vimentin was detected by Western blot. The target relationships among MIR503HG, miR-107 and Par4 were predicted by StarBase and TargetScan, and verified by luciferase reporter and RNA pull-down assay. The xenograft tumor model was constructed in mice to verify the inhibitory effect of MIR503HG in vivo. RESULTS: The expression of MIR503HG was decreased in colon cancer tissues and cell lines. MIR503HG overexpression inhibited cell proliferation, migration and invasion, promoted cell apoptosis, down-regulated N-cadherin and Vimentin, and up-regulated E-cadherin in colon cancer. MIR503HG negatively regulated its target miR-107. MiR-107 overexpression reversed the anti-tumor effects of MIR503HG overexpression on colon cancer cells. Par4 was a target of miR-107, which was positively regulated by MIR503HG. The promoting effects of MIR503HG silencing on colon cancer cells were eliminated by Par4 overexpression. CONCLUSION: MIR503HG regulated Par4 via sponging miR-107 in colon cancer, which promoting a new idea for the treatment of colon cancer.

LncRNA MIR503HG inhibits cell migration and invasion via miR-103/OLFM4 axis in triple negative breast cancer.

Long non-coding RNA MIR503 host gene (MIR503HG) is located on chromosome Xq26.3, and has been found to be deregulated in many types of human malignancy and function as tumour suppressor or promoter based on cancer types. The role of MIR503HG in breast cancer was still unknown. In our study, we found MIR503HG expression was significantly decreased in triple-negative breast cancer tissues and cell lines. Furthermore, we observed low MIR503HG expression was correlated with late clinical stage, lymph node metastasis and distant metastasis. In the survival analysis, we observed that triple-negative breast cancer patients with low MIR503HG expression had a statistically significant worse prognosis compared with those with high MIR503HG expression, and low MIR503HG expression was a poor independent prognostic factor for overall survival in triple-negative breast cancer patients. The study in vitro suggested MIR503HG inhibits cell migration and invasion via miR-103/OLFM4 axis in triple negative breast cancer. In conclusion, MIR503HG functions as a tumour suppressive long non-coding RNA in triple negative breast cancer.

lncRNA MIR503HG functioned as a tumor suppressor and inhibited cell proliferation, metastasis and epithelial-mesenchymal transition in bladder cancer.

Bladder cancer is the most common malignancy with high recurrence. Currently, the long noncoding RNAs (lncRNAs) have been suggested to play vital roles in the pathogenesis of bladder cancer. The present study investigated the role of lncRNA MIR503 host gene (MIR503HG) in the pathogenesis of bladder cancer by using both in vitro and in vivo functional assays. The expression of MIR503HG was downregulated in bladder cancer tissues and cell lines. Low expression of MIR503HG was associated with advanced tumor stage, advanced histological grade, and lymph node metastasis. Ectopic expression of MIR503HG inhibited cell proliferation, cell growth, cell invasion, and migration, and also promoted cell apoptosis and inhibited cell cycle progression in SW780 cells. In parallel, T24 cells were used for loss-of-function studies. Knockdown of MIR503HG promoted the cancer cell proliferation and increased the migration and invasion abilities of T24 cells. In addition, knockdown of MIR503HG reduced the cell apoptotic rate in cancer cells and promoted cell cycle progression. Furthermore, MIR503HG overexpression decreased the epithelial-mesenchymal transition-related mRNA and protein levels of ZEB1, Snail, N-cadherin, and vimentin, with an increase in E-cadherin level. Consistently, knockdown of MIR503HG showed the opposite effects. In vivo xenograft, nude mice results showed that overexpression of MIR503HG suppressed the tumor growth and tumor metastasis. In conclusion, our results identified a novel lncRNA MIR503HG that exhibited significant antiproliferation, antimigration/invasion effects on bladder cancer cells both in vitro and in vivo, which may hold a therapeutic promise to treat bladder cancer.

The Long Non-Coding RNA MIR503HG Enhances Proliferation of Human ALK-Negative Anaplastic Large-Cell Lymphoma.

Anaplastic lymphoma kinase (ALK)-negative anaplastic large-cell lymphoma (ALCL) is a rare type of highly malignant, non-Hodgkin lymphoma. Currently, only a few gene rearrangements have been linked to ALK-negative ALCL progression. However, the specific molecular mechanisms underlying the growth of ALK-negative ALCL tumors remain unclear. Here, we investigated aberrantly expressed, long non-coding RNAs (lncRNAs) in ALK-negative ALCL and assessed their potential biological function. MIR503HG (miR-503 host gene) was highly expressed in ALK-negative cell lines and was significantly upregulated in tumors in mice formed from ALK-negative ALCL cell lines. Depletion of MIR503HG suppressed tumor cell proliferation in vivo and in vitro; conversely, its overexpression enhanced tumor cell growth. MIR503HG-induced proliferation was mediated by the induction of microRNA-503 (miR-503) and suppression of Smurf2, resulting in stabilization of the tumor growth factor-ß receptor (TGFBR) and enhanced tumor cell growth. Collectively, these findings support a potential role for MIR503HG in cancer cell proliferation through the miR-503/Smurf2/TGFBR axis and indicate that MIR503HG is a potential marker in ALK-negative ALCL.

MIR503HG: A potential diagnostic and therapeutic target in human diseases.

LncRNAs are involved in many physiological and pathological processes, including chromatin remodeling, transcription, posttranscriptional gene expression, mRNA stability, translation, and posttranslational modification, and their functions depend on subcellular localization. MIR503HG is a lncRNA as well as a host gene for the miRNAs miR-503 and miR-424. MIR503HG functions independently or synergistically with miR-503. MIR503HG affects cell proliferation, invasion, metastasis, apoptosis, angiogenesis, and other biological behaviors. The mechanism of MIR503HG in disease includes interaction with protein, sponging miRNA to regulate downstream target gene, and participation in NF-κB, TGF-ß, ERK/MAPK, and PI3K/AKT signaling pathways. In this review, we summarize the molecular mechanisms of MIR503HG in disease and its potential applications in diagnosis, prognosis, and treatment. We also raise some unanswered questions in this area, providing insights for future research.

MIR503HG silencing promotes endometrial stromal cell progression and metastasis and suppresses apoptosis in adenomyosis by activating the Wnt/ß­catenin pathway via targeting miR­191.

MIR503HG is a 786 bp long lncRNA located on chromosome Xq26.3, and it can regulate diverse cellular processes. The pathogenesis of adenomyosis (AD) is associated with endometrial stromal cells (ESCs). The present study investigated the specific role of MIR503HG in AD pathogenesis and progression using ESCs derived from the endometrium of patients with AD as a model. Expression of MIR503HG and microRNA (miR)-191 were assessed using reverse transcription-quantitative PCR. An immunocytochemistry assay was used to detect cytokeratin- or vimentin-positive ESCs. Transfections of ESCs with MIR503HG overexpression plasmid, short hairpin-MIR503HG and miR-191 inhibitor were performed. ESC viability, migration, invasion and apoptosis were evaluated using Cell Counting Kit-8, Transwell and flow cytometry assays. The association between MIR503HG and miR-191 was predicted by StarBase and confirmed using a dual-luciferase reporter assay. Expression of epithelial-mesenchymal transition-related markers (E-cadherin and N-cadherin) and Wnt/ß-catenin pathway-related molecules (ß-catenin) in ESCs were analyzed by western blotting. The isolated ESCs were vimentin-positive and cytokeratin-negative. MIR503HG was lowly expressed in the endometrial tissues derived from patients with AD. MIR503HG overexpression hindered ESC viability, migration and invasion while enhancing the apoptosis and downregulating miR-191 expression. MIR503HG knockdown induced the opposite effects, accompanied by downregulation of the E-cadherin expression and upregulation of N-cadherin and ß-catenin levels. MIR503HG directly targeted miR-191 that was highly expressed in endometrial tissues derived from patients with AD. In ESCs, downregulation of miR-191 inhibited the viability, migration and invasion and the expression of N-cadherin and ß-catenin levels while enhancing the apoptosis and E-cadherin expression in ESCs. Moreover, downregulation of miR-191 partially reversed the effect of MIR503HG knockdown. Collectively, overexpressed MIR503HG impeded the proliferation and migration of ESCs derived from endometrium of patients with AD, while promoting apoptosis via inhibition of the Wnt/ß-catenin pathway via targeting miR-191.

MIR503HG impeded ovarian cancer progression by interacting with SPI1 and preventing TMEFF1 transcription.

MIR503 host gene (MIR503HG) acts as an important tumor suppressor in many human cancers, but its role and regulatory mechanism in ovarian cancer need to be further studied. In this study, lower expressed MIR503HG was observed in ovarian tumor tissues and cells than in adjacent normal tissues and normal human ovarian epithelial cells. MIR503HG overexpression impaired the proliferative, invasive and EMT properties, and facilitated cell apoptosis in ovarian cancer cells. Nuclear and cytoplasmic separation test suggested that MIR503HG was mainly expressed in the nucleus. RNA immunoprecipitation and RNA pull-down assays confirmed that MIR503HG could bind to transcription factor SPI1 (Spi-1 proto-oncogene), and dual luciferase reporter gene and Chromatin immunoprecipitation assays verified that SPI1 could bind to TMEFF1 (Transmembrane protein with EGF like and two follistatin like domains 1) promoter, suggesting that MIR503HG suppressed TMEFF1 expression by competitively binding SPI1 and blocking transcriptional activation of TMEFF1. Moreover, interference with TMEFF1 reversed the promotion effect of MIR503HG silence on the malignant behaviors of ovarian cancer cells. Moreover, MIR503HG knockdown activated the MAPK and PI3K/AKT pathways by increasing the expression of TMEFF1. In addition, overexpression of MIR503HG in vivo suppressed the tumorigenic ability in nude mice. In conclusion, MIR503HG acted as a tumor suppressor lncRNA in ovarian cancer by suppressing transcription factor SPI1-mediated transcriptional activation of TMEFF1.

A Novel MIR503HG/miR-497-5p/CCL19 Axis Regulates High Glucose-Induced Cell Apoptosis, Inflammation, and Fibrosis in Human HK-2 Cells.

Long non-coding RNAs (lncRNAs) play crucial roles in the development of diabetic nephropathy (DN). Here, we explored the activity and mechanism of MIR503 host gene (MIR503HG) in high glucose (HG)-evoked cytotoxicity in HK-2 cells. MIR503HG, microRNA (miR)-497-5p, and C-C motif chemokine ligand 19 (CCL19) were quantified by quantitative real-time PCR (qRT-PCR) and western blot. The direct relationship between miR-497-5p and MIR503HG or CCL19 was confirmed by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Cell viability and apoptosis were evaluated by XTT assay and flow cytometry, respectively. Our data showed that MIR503HG was overexpressed in HG-stimulated HK-2 cells. Knockdown of MIR503HG alleviated HG-evoked cell apoptosis, inflammation, and fibrosis in HK-2 cells. Mechanistically, MIR503HG regulated miR-497-5p expression via a binding site. MIR503HG depletion reduced HG-evoked cell apoptosis, inflammation, and fibrosis in HK-2 cells by up-regulating miR-497-5p. Moreover, miR-497-5p directly targeted and suppressed CCL19. MiR-497-5p-mediated suppression of CCL19 relieved HG-induced cell apoptosis, inflammation, and fibrosis in HK-2 cells. Furthermore, MIR503HG regulated CCL19 expression via miR-497-5p competition. Our findings identify a new MIR503HG/miR-497-5p/CCL19 network in the regulating HG-evoked cell apoptosis, inflammation, and fibrosis in HK-2 cells.

Neutrophil Extracellular Traps (NETs) Promote Non-Small Cell Lung Cancer Metastasis by Suppressing lncRNA MIR503HG to Activate the NF-κB/NLRP3 Inflammasome Pathway.

Neutrophil extracellular traps (NETs) that are produced in the tumour microenvironment (TME) have been suggested to play an essential role in the dissemination of metastatic cancer under multiple infectious and inflammatory conditions. However, the functions of NETs in promoting non-small cell lung cancer (NSCLC) metastasis and the underlying mechanisms remain incompletely understood. Here, we found that NETs promoted NSCLC cell invasion and migration by inducing epithelial to mesenchymal transition (EMT). To explore how NETs contribute to NSCLC metastasis, microarrays were performed to identify substantial numbers of long noncoding RNAs (lncRNAs) and mRNAs that were differentially expressed in NSCLC cells after stimulation with NETs. Interestingly, we observed that the expression of lncRNA MIR503HG was downregulated after NETs stimulation, and ectopic MIR503HG expression reversed the metastasis-promoting effect of NETs in vitro and in vivo. Notably, bioinformatics analysis revealed that differentially expressed genes were involved in the NOD-like receptor and NF-κB signalling pathways that are associated with inflammation. NETs facilitated EMT and thereby contributed to NSCLC metastasis by activating the NF-κB/NOD-like receptor protein 3 (NLRP3) signalling pathway. Further studies revealed that MIR503HG inhibited NETs-triggered NSCLC cell metastasis in an NF-κB/NLRP3-dependent manner, as overexpression of NF-κB or NLRP3 impaired the suppressive effect of MIR503HG on NETs-induced cancer cell metastasis. Together, these results show that NETs activate the NF-κB/NLRP3 pathway by downregulating MIR503HG expression to promote EMT and NSCLC metastasis. Targeting the formation of NETs may be a novel therapeutic strategy for treating NSCLC metastasis.

lncRNA MIR503HG inhibits cell proliferation and promotes apoptosis in TNBC cells via the miR-224-5p/HOXA9 axis.

Triple-negative breast cancer (TNBC) is a highly invasive subtype of breast cancer. This study investigated the molecular mechanism and influences of MIR503HG, miR-224-5p, and homeobox A9 (HOXA9) on TNBC cell growth and migration. Dual-luciferase reporter gene and RNA immunoprecipitation were performed to examine the regulation of MIR503HG, miR-224-5p, and HOXA9. Cell proliferation, apoptosis, migration, and invasion were evaluated by colony formation, flow cytometry, and Transwell assays. Finally, nude mice were employed to investigate the influence of MIR503HG on TNBC tumor growth. HOXA9 protein levels were detected by immunohistochemical staining. MIR503HG and HOXA9 expression were reduced in TNBC, while miR-224-5p was increased. Overexpression of MIR503HG or HOXA9 reduced the cell migration ability and proliferation and promoted apoptosis, and knockdown of MIR503HG or overexpression of miR-224-5p exhibited the opposite effects. Furthermore, MIR503HG promoted HOXA9 expression by inhibiting miR-224-5p. Overexpression of miR-224-5p reversed the effects of MIR503HG overexpression on TNBC cells, while overexpression of HOXA9 reversed the effect of MIR503HG knockdown. Additionally, an in vivo study proved that MIR503HG inhibited TNBC tumor growth via the miR-224-5p/HOXA9 axis. MIR503HG inhibited cell proliferation and promoted the apoptosis of TNBC cells via the miR-224-5p/HOXA9 axis, which may function as a novel target for the treatment of TNBC.

The LncRNA MIR503HG/miR-224-5p/TUSC3 Signaling Cascade Suppresses Gastric Cancer Development via Modulating ATF6 Branch of Unfolded Protein Response.

BACKGROUND: Unfolded protein response (UPR)-mediated tumor-promoting functions have been identified in multiple cancers, and this study focused on investigating the role and molecular mechanisms of UPR in modulating gastric cancer (GC) pathogenesis. METHODS: The bioinformatics analysis was performed to examine the expression status of cancer associated genes in patients with stomach adenocarcinoma (STAD) and predict the targeting sites of miR-224-5p with LncRNA MIR503HG and TUSC3. Genes expressions were quantified by Real-Time qPCR, Western Blot and immunohistochemistry (IHC). Cell proliferation, viability, apoptosis and mobility were evaluated by MTT assay, trypan blue staining assay, flow cytometer and transwell assay, respectively. The binding sites were validated by dual-luciferase reporter gene system assay. RESULTS: LncRNA MIR503HG and TUSC3 were downregulated, but miR-224-5p was upregulated in GC tissues and cells, in contrast with their normal counterparts. Further gain- and loss-of-function experiments validated that the malignant phenotypes in GC cells, including cell proliferation, invasion, epithelial-mesenchymal transition (EMT) and tumorigenesis, were negatively regulated by LncRNA MIR503HG. Mechanistically, LncRNA MIR503HG upregulated TUSC3 in GC cells through sponging miR-224-5p, resulting in the repression of GC progression. Finally, we validated that knock-down of ATF6, but not other two branches of UPR (PERK1 and IRE1), partially rescued cell proliferation and EMT in the GC cells with LncRNA MIR503HG overexpression. CONCLUSIONS: Targeting the LncRNA MIR503HG/miR-224-5p/TUSC3 signaling cascade suppressed ATF6-mediated UPR, resulting in the blockage of GC development.

LncRNA miR503HG inhibits epithelial-mesenchymal transition and angiogenesis in hepatocellular carcinoma by enhancing PDCD4 via regulation of miR-15b.

OBJECTIVE: To reveal the effect of lncRNA miR503HG on epithelial-mesenchymal transition (EMT) and angiogenesis in hepatocellular carcinoma (HCC). METHODS: The expressions of miR503HG, miR-15b and PDCD4 in HCC tissues and cell lines were measured. After cell transfection, Transwell assay tested the migration and invasion ability of HCC cells. qRT-PCR and Western blot detected the expressions of EMT markers (E-cad, N-cad, Vim and Snail-1). Matrigel-based tube formation assay assessed the angiogenesis capacity of human umbilical vein endothelial cells (HUVECs) cultured in conditioned medium of treated HCC cells. ELISA detected the level of VEGF in supernatant of HUVECs. RIP, RNA pulldown and dual-luciferase reporter assay were applied to verify the binding of miR-15b to miR503HG or PDCD4. pcDNA3.1-miR503HG-BEL-7404 cells or pcDNA3.1-BEL-7404 cells were implanted into nude mice for construction of HCC model in vivo. RESULTS: miR503HG and PDCD4 were under-expressed and miR-15b was over-expressed in HCC cells and tissues. Up-regulation of miR503HG and PDCD4 or inhibition of miR-15b hindered migration, invasion and EMT of HCC cells and angiogenesis of HUVECs. Both miR503HG and PDCD4 could bind to miR-15b. Over-expression of miR503HG suppressed HCC growth and angiogenesis in nude mice. CONCLUSION: LncRNA miR503HG suppresses EMT and angiogenesis in HCC via miR-15b/PDCD4 axis.

LncRNA miR503HG interacts with miR-31-5p through multiple ways to regulate cancer cell invasion and migration in ovarian cancer.

The role of lncRNA miR503HG has been investigated in several types of cancer, but its functions in ovarian cancer (OC) is unclear. Analysis of TCGA dataset revealed a 50-fold lower expression level of miR503HG in OC tissues than that in non-tumor tissues, indicating the involvement of miR503HG in OC. Results in this study showed that miR503HG was downregulated in OC and predicted poor survival. Expression of miR503HG negatively correlated with the expression of miR-31-5p across OC and non-tumor tissues. RNA-RNA interaction analysis revealed that miR503HG can interact with miR-31-5p. Dual-luciferase assay showed that miR-31-5p and miR503HG may directly interact with each other. Methylation specific PCR (MSP) showed that overexpression of miR503HG led to increased methylation level of miR-31-5p gene. Transwell assay showed that overexpression of miR-31-5p resulted in increased invasion and migration rates of OC cells. Overexpression of MiR503HG played an opposite role and attenuated the effects of overexpressing miR-31-5p. Therefore, miR503HG may promote the methylation of miR-31-5p and serve as its sponge to inhibit OC cell invasion and migration.

LncRNA MIR503HG Promotes High-Glucose-Induced Proximal Tubular Cell Apoptosis by Targeting miR-503-5p/Bcl-2 Pathway.

AIM: More than half of microRNAs are located in genes. LncRNAs are host genes of intronic microRNAs that regulate intracellular splicing to form pre-miRNAs that are processed to mature miRNAs. MicroRNAs work as partners or antagonists of their host lncRNAs by fine-tuning their target genes. However, whether lncRNA-MIR503HG (miR-503 host gene) is co-transcribed with miR-503 and affects miR-503 splicing, thereby affecting its target gene Bcl-2 expression and cell mitochondrial apoptotic pathway in diabetic nephropathy (DN) is currently unknown. METHODS: Human proximal tubular (HK-2) cells cultured in high glucose were transfected with lncRNA MIR503HG overexpression/inhibition plasmid and miR-503 mimics/inhibitor. Real-time quantitative PCR was used to measure the expression levels of lncRNA MIR503HG, pre-miR-503, miR-503 and Bcl-2. Western blot was used to measure the protein expressions of Bcl-2, Bax, Cytc and cleaved-caspase 9/3. Annexin V/PI flow cytometry was used to measure apoptosis. RESULTS: Host lncRNA MIR503HG was co-transcribed with miR-503. MIR503HG regulated the expression of miR-503 by affecting miR-503 splicing synthesis. In the presence of high glucose, the expression levels of lncRNA MIR503HG and miR-503 were up-regulated in HK-2 cells cultured in high glucose. Bcl-2 expression was inhibited and levels of apoptosis-related proteins Cytc and Bax were increased in HK-2 cells cultured in high glucose, all of which promoted the caspase cascade reaction, leading to increased caspase-9 and caspase-3 shear fragments inducing apoptosis of the mitochondrial pathway. Inhibition of MIR503HG led to a reduction in miR-503 expression, up-regulated its target gene Bcl-2, inhibited the expression levels of Bax and other apoptosis-related proteins and attenuated HK-2 cell apoptosis induced by high glucose. Co-transfection of miRNA-503 partially offset the effect of MIR503HG-siRNA. CONCLUSION: MIR503HG indirectly regulates Bcl-2 by promoting the co-transcription of miRNA-503 to participate high-glucose-induced proximal tubular cell apoptosis, providing a new target for diabetic nephropathy treatment.

Structure and expression of the long noncoding RNA gene MIR503 in humans and non-human primates.

Recent technical and other advances in genomics provide unique opportunities to improve our understanding of human physiology and disease predisposition through a detailed analysis of gene structure and expression by examining data in public genome and gene-expression repositories. Yet, the vast majority of human genes remain understudied. This is particularly true of genes for long noncoding RNAs (lncRNAs). Here, we describe the detailed characterization of MIR503HG, a lncRNA gene found on the X chromosome in humans. Using information extracted from public databases, we show that human MIR503HG is a 5-exon gene, and that it is highly conserved among 5 non-human primates spanning over 85 million years ago of evolutionary diversification. MIR503HG is transcribed and processed into multiple distinct RNAs in each of these species through differential exon use and alternative RNA splicing, with a higher abundance of transcripts being found in reproductive tissues, especially during the early stages of ovary and testis development, indicating a possible role in reproductive biology. Furthermore, in select reproductive system cancers, MIR503HG transcripts are downregulated, with higher levels of RNA expression being associated with clinical outcomes. Collectively, these investigations show how the use of genomic, gene expression, and other genetic resources can lead to new insights about human biology and disease, and argue that MIR503HG is worthy of additional study.

LncRNA miR503HG Regulates the Drug Resistance of Recurrent Cervical Squamous Cell Carcinoma Cells by Regulating miR-155/Caspase-3.

INTRODUCTION: The purpose of this study is to investigate the role of long non-coding RNA (lncRNA) miR503 Host Gene (miR503HG) in cervical squamous cell carcinoma (CSCC). METHODS: Analysis of TCGA dataset revealed that expression levels of miR503HG in CSCC tissues were over 12 times lower than those in non-tumor tissues, indicating its involvement in CSCC. RESULTS: In this study, we observed that levels of miR503HG in plasma were significantly lower in CSCC patients than in healthy participants. The cisplatin-based treatment further downregulated miR503HG in both patients and CSCC cells. MiR503HG overexpression in CSCC cells led to the suppression of miR-155 and elevation of Caspase-3, acting as the downstream target of miR-155. Cell apoptosis analysis showed that miR503HG and Caspase-3 overexpression led to an increased cell apoptosis rate under Cisplatin treatment. MiR-155 played the opposite role and attenuated the functions of Caspase-3 and miR503HG overexpression. CONCLUSION: Therefore, miR503HG may regulate the drug resistance of CSCC cells by regulating mir-155/Caspase-3.

Knockdown of lncRNA MIR503HG suppresses proliferation and promotes apoptosis of non-small cell lung cancer cells by regulating miR-489-3p and miR-625-5p.

The long noncoding RNA (lncRNA) MIR503HG has been shown to play an important role in cancer development. The aim of the present study was to investigate the potential roles of MIR503HG in the proliferation and apoptosis of non-small cell lung cancer cell (NSCLC). We used short hairpin RNA (shRNA) against MIR503HG to knock down and vector containing full length of MIR503HG to overexpress MIR503HG in NSCLC cells. The expression of MIR503HG in NSCLC tissues and cells was detected and the effects of MIR503HG on the cell proliferation and apoptosis were determined. Results showed that the expression of MIR503HG was significantly upregulated in NSCLC tissues compared with adjacent tissues. We found that downregulation of MIR503HG could clearly suppressed cell proliferation and cell cycle progression. Moreover, MIR503HG knockdown also promoted apoptosis of NSCLC cells. As expected, overexpression of MIR503HG significantly promoted cell proliferation and inhibited cell apoptosis in NSCLC NCI-H1975 cells. We predicted and verified miR-489-3p and miR-625-5p as the direct targets of MIR503HG by bioinformatics analysis and luciferase reporter assay. Mechanically, MIR503HG negatively regulated miR-489-3p and miR-625-5p expressions in NSCLC cells. Moreover, downregulation of miR-489-3p and miR-625-5p weaken the decreased cell proliferation and increased apoptosis of A549 cells after MIR503HG knocking down. In conclusion, knockdown of MIR503HG suppressed proliferation and promoted apoptosis of NSCLC cells through regulating miR-489-3p and miR-625-5p. Our findings of this study suggested that MIR503HG could be a potential therapeutic target for NSCLC development.

LncRNA MIR503HG Inhibits Non-Small Cell Lung Cancer Cell Proliferation by Inducing Cell Cycle Arrest Through the Downregulation of Cyclin D1.

INTRODUCTION: LncRNA MIR503HG has been reported to participate in liver cancer and ALK-negative anaplastic large-cell lymphoma, while its role in non-small cell lung cancer (NSCLC) is unknown. We therefore investigated the functions of lncRNA MIR503HG in NSCLC. METHODS: MIR503HG expression in paired cancer and non-cancer tissues from NSCLC patients was analyzed by RT-qPCR. The interaction between cyclin D1 and MIR503HG was analyzed by overexpression experiments. Cell cycle analysis was performed by flow cytometry. Cell proliferation was analyzed by CCK-8 assay. RESULTS: MIR503HG was downregulated in NSCLC and low levels of MIR503HG were associated with poor survival. In contrast, cyclin D1 was upregulated in NSCLC, and cyclin D1 and MIR503HG were inversely correlated. In NSCLC cells, overexpression experiments revealed that MIR503HG functioned as an upstream inhibitor of cyclin D1. MIR503HG overexpression led to G1 cell cycle arrest, while overexpression of cyclin D1 attenuated the effects of MIR503HG overexpression. Similarly, MIR503HG overexpression resulted in reduced cell proliferation rate, while overexpression of cyclin D1 caused the increased cell proliferation rate and attenuated effects of MIR503HG overexpression. CONCLUSION: MIR503HG inhibits NSCLC cell proliferation by inducing cell cycle arrest through the downregulation of cyclin D1.