LncRNA HAND2-AS1 exerts anti-oncogenic effects on ovarian cancer via restoration of BCL2L11 as a sponge of microRNA-340-5p

In the early stage of ovarian cancer (OC), molecular biomarkers are critical for its diagnosis and treatment. Nevertheless, there is little research on the mechanism underlying tumorigenesis in OC. Herein, we aimed to explore whether long noncoding RNA (lncRNA) HAND2-AS1 participated in the regulation of the cell proliferation, migration, and apoptosis of OC by regulating B-cell lymphoma 2 like 11 (BCL2L11) and microRNA-340-5p (miR-340-5p). Differentially expressed lncRNAs in OC were screened by microarray-based analysis. HAND2-AS1, BCL2L11, and miR-340-5p expression was assessed in normal ovarian and OC tissues and human OC cell lines. Then, the relationships among HAND2-AS1, BCL2L11, and miR-340-5p were explored. Ectopic expression and depletion experiments were applied to analyze the effects of HAND2-AS1, miR-340-5p and BCL2L11 on migration, invasion, and proliferation of OC cells, as well as apoptosis. Lastly, the tumor xenograft in nude mice was conducted to test the tumorigenesis in vivo. In silico analysis displayed poor expression of HAND2-AS1 in OC. HAND2-AS1 specifically sponged with miR-340-5p which was found to directly target BCL2L11. Importantly, HAND2-AS1 or BCL2L11 overexpression or miR-340-5p downregulation resulted in reduction of cell invasion and migration, together with decrease of cell proliferation and increase of cell apoptosis in OC. Besides, high-expressed HAND2-AS1 inhibited the tumorigenesis in nude mice. To sum up, these data suggests HAND2-AS1 as an anti-oncogene in OC through upregulation of BCL2L11 by competitively binding to miR-340-5p, which demonstrates that there are potential diagnosis and therapy values of HAND2-AS1 in OC.     

Long non-coding RNA ZNF667-AS1 retards the development of esophageal squamous cell carcinoma via modulation of microRNA-1290-mediated PRUNE2

Abnormal long non-coding RNAs (lncRNAs) have been detected in esophageal squamous cell carcinoma (ESCC). Here, we focused on lncRNA ZNF667-AS1 and its downstream mechanism in ESCC progression. Differentially expressed lncRNAs in ESCC were predicted by bioinformatics analysis. ZNF667-AS1, microRNA-1290 (miR-1290), and prune homolog 2 with BCH domain (PRUNE2) expression was determined with their relationship in cell biological processes analyzed also by means of gain- and loss-of-function assays. Xenograft mouse models were performed to re-produce the in vitro findings. We found a decline in ZNF667-AS1 expression in ESCC tissues and cell lines. ZNF667-AS1 overexpression indicated a favorable prognosis of ESCC sufferers. ZNF667-AS1 overexpression suppressed ESCC cell malignant potentials. ZNF667-AS1 reduced miR-1290 to result in upregulation of the miR-1290 target gene PRUNE2. The inhibiting property of ZNF667-AS1 on the malignant characteristics of ESCC cells was achieved by disrupting the miR-1290-mediated downregulation of PRUNE2. ZNF667-AS1 suppressed the tumorigenesis of ESCC in vivo. Collectively, our study demonstrates that ZNF667-AS1 can function as a tumor suppressor in ESCC by upregulating PRUNE2 and downregulating miR-1290.     

LncRNA HAND2-AS1 inhibits 5-fluorouracil resistance by modulating miR-20a/PDCD4 axis in colorectal cancer

BackgroundChemoresistance is one of the main obstacles in the therapy of human cancers, including colorectal cancer (CRC). Long non-coding RNA heart and neural crest derivatives expressed 2-antisense RNA 1 (lncRNA HAND2-AS1) has been demonstrated to be associated with CRC. However, the function of HAND2-AS1 in 5-Fluorouracil (5-FU) resistance of CRC remains unclear.MethodsQuantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expression of HAND2-AS1, miR-20a and programmed cell death factor 4 (PDCD4) mRNA. 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay was conducted to evaluate IC50 of 5-FU and cell proliferation. Flow cytometry analysis was used to determine cell apoptosis. Transwell assay was carried out to measure cell migration and invasion. Western blot assay was conducted to examine the protein levels of B-cell lymphoma-2 (Bcl-2), BCL2-Associated X (Bax), matrix metalloprotein 2 (MMP2), MMP9 and PDCD4. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull down assay were utilized to verify the combination between miR-20a and HAND2-AS1. Dual-luciferase reporter assay was used to analyze the association between miR-20a and PDCD4. Murine xenograft assay was used to confirm the function of HAND2-AS1 in vivo.ResultsHAND2-AS1 and PDCD4 were downregulated and miR-20a was upregulated in 5-FU-resistant CRC tissues and cells. HAND2-AS1 suppressed 5-FU resistance, cell proliferation, migration and invasion and promoted cell apoptosis in 5-FU-resistant CRC cells. HAND2-AS1 acted as a sponge of miR-20a to regulate PDCD4 expression. Moreover, HAND2-AS1 suppressed cell progression and 5-FU resistance by upregulating PDCD4 via sponging miR-20a in 5-FU-resistant CRC cells. Besides, HAND2-AS1 inhibited tumor growth in vivo.ConclusionHAND2-AS1/miR-20a/PDCD4 axis inhibited cell progression and 5-FU resistance in 5-FU-resistant CRC cells.     

Long noncoding RNA lnc-ABCA12-3 promotes cell migration,invasion, and proliferation by regulating fibronectin 1 in esophageal squamous cell carcinoma

Long noncoding RNAs (lncRNAs) have been shown to play important roles in human cancers, including esophageal squamous cell carcinoma (ESCC). We previously demonstrated that a novel lncRNA, lnc-ABCA12-3, was overexpressed in ESCC tissues. However, the exact function of lnc-ABCA12-3 is unknown. In the current study, we aimed to evaluate the expression of lnc-ABCA12-3 in ESCC and to explore the potential mechanism of lnc-ABCA12-3 in cell migration, invasion, and proliferation. We showed that lnc-ABCA12-3 was upregulated in ESCC tumor tissues and cell lines. The increased expression of lnc-ABCA12-3 was positively associated with advanced tumor-node-metastasis stages and poor prognosis. The knockdown of lnc-ABCA12-3 inhibited the cell migration, invasion, and proliferation abilities of KYSE-510 and Eca-109 cells. We also found that fibronectin 1 (FN1) was upregulated in ESCC tumor tissues. The expression of FN1 messenger RNA was positively correlated with the expression of lnc-ABCA12-3 in ESCC tumor tissues. After lnc-ABCA12-3 knockdown, the expression of FN1 was downregulated. In addition, the overexpression of FN1 restored the abilities of cell migration, invasion and proliferation in Eca-109 cells. Further studies indicated that lnc-ABCA12-3 acted as a competing endogenous RNA for miR-200b-3p to regulate FN1 expression. In conclusion, these results suggest that lnc-ABCA12-3 is a novel oncogene in tumorigenesis and that its high expression is related to a poor prognosis for patients with ESCC. lnc-ABCA12-3 promotes cell migration, invasion, and proliferation via the regulation of FN1 in ESCC. Our data suggest that lnc-ABCA12-3 might serve as a potential prognostic biomarker and therapeutic target for ESCC.     

lncRNA CASC11 promotes cancer cell proliferation in bladder cancer through miRNA-150

Long noncoding RNAs (lncRNAs) CASC11 is an oncogenic lncRNA in gastric cancer and colorectal cancer. Our study aimed to investigate the role of lncRNA CASC11 in bladder cancer. In this study we showed that plasma lncRNA CASC11 was upregulated, while plasma miRNA-150 was downregulated in patients with early-stage bladder cancer than in healthy controls. Altered expression of plasma lncRNA CASC11 and miRNA-150 separated patients with bladder cancer from healthy controls. lncRNA CASC11 expression was inversely correlated with miRNA-150 expression in patients with bladder cance but not in healthy controls. Overexpression of lncRNA CASC11 mediated the inhibition of miRNA-150 expression in cancer cells, while miRNA-150 overexpression did not significantly alter lncRNA CASC11 expression. lncRNA CASC11 overexpression promoted, while miRNA-150 overexpression inhibited cancer cell proliferation. miRNA-150 also attenuated the enhancing effects of lncRNA CASC11 overexpression on cancer cell proliferation. However, overexpression of lncRNA CASC11 showed no significant effects on cancer cell migration and invasion. Therefore, lncRNA CASC11 may promote cancer cell proliferation in bladder cancer, and the actions of lncRNA CASC11 are likely through miRNA-150.     

AGAP2-AS1 serves as an oncogenic lncRNA and prognostic biomarker in glioblastoma multiforme

Long noncoding RNA (lncRNA) AGAP2 antisense RNA 1 (AGAP2-AS1) has been suggested to function as an oncogenic lncRNA in lung cancer, breast cancer, and anaplastic glioma. However, the expression pattern and molecular mechanism of AGAP2-AS1 in glioblastoma multiforme (GBM) remains unknown. The purpose of this study is to present more evidence about the clinical and biological function of AGAP2-AS1 in GBM. In our results, we found AGAP2-AS1 expression was increased in GBM compared with adjacent normal brain tissues or low-grade glioma tissues, and there was no significantly different between low-grade glioma tissues and normal tissues. Kaplan-Meier survival analysis indicated patients with GBM having high-expression of AGAP2-AS1 had shorter overall survival time than those with low expression of AGAP2-AS1. The loss-of-function studies showed that downregulation of AGAP2-AS1 depressed cell proliferation, migration, and invasion, and promoted cell apoptosis in GBM. In summary, AGAP2-AS1 is a prognostic biomarker for patients with GBM, and functions as an oncogenic lncRNA to modulate GBM cell proliferation, apoptosis, migration, and invasion, which suggests that AGAP2-AS1 is potential therapeutic target for GBM.     

MiR-526b targets lncRNA SLC16A1-AS1 to suppress cell proliferation in triple-negative breast cancer

The present study investigated the potential interaction between miR-526b and lncRNA SLC16A1-AS1 in triple-negative breast cancer (TNBC). Expression of miR-526b and SLC16A1-AS1 in TNBC tumor tissues and paired nontumor tissues from 60 TNBC patients was detected by real-time polymerase chain reaction (RT-qPCR). The interaction between miR-526b and SLC16A1-AS1 was evaluated with overexpression experiments, followed by RT-qPCR. The proliferation and migration of cells were detected with cell counting kit-8 assay and Transwell assay, respectively. Apoptosis of cells was assessed by cell apoptosis assay. The expression of apoptosis-related proteins was quantified by Western blot analysis. MiR-526b was predicted to bind with SLC16A1-AS1. Overexpression of miR-526b in TNBC cells decreased the expression levels of SLC16A1-AS1, while overexpression of SLC16A1-AS1 did not affect the expression of miR-526b. In TNBC tissues, miR-526b was downregulated in TNBC tissues, while SLC16A1-AS1 was upregulated in TNBC tissues compared to that in nontumor tissues. The expression of SLC16A1-AS1 and miR-526b were inversely correlated. In vitro experiments showed that overexpression of SLC16A1-AS1 promoted cell proliferation and invasion but suppressed cell apoptosis. MiR-526b played an opposite role and suppressed the function of SLC16A1-AS1. MiR-526b is downregulated in TNBC and it targets SLC16A1-AS1 to regulate proliferation, apoptosis, and invasion of TNBC cells.     

Long noncoding RNA LINC-PINT is inhibited in gastric cancer and predicts poor survival

Long noncoding RNA (lncRNA) LINC-PINT expression is inhibited in many types of cancer cells, suggesting its role as a tumor suppressor. However, the functionality of LINC-PINT in gastric cancer and the clinical values are unknown. In the present study, we found that lncRNA LINC-PINT was downregulated, while microRNA-21 (miR-21) was upregulated in tumor tissues than in adjacent healthy tissues of gastric cancer patients. A significant and inverse correlation between expression levels of lncRNA LINC-PINT and miR-21 was found in both tumor tissues and adjacent healthy tissues. The low expression level of LINC-PINT and high expression level of the miR-21 tumor were correlated with poor prognosis. LINC-PINT overexpression casued miR-21 inhibition in cells of human gastric cancer cell lines, while miR-21 overexpression did not alter LINC-PINT expression. LINC-PINT overexpression led to inhibited, while miR-21 overexpression led to promoted proliferation, migration, and invasion of gastric cancer cells. Effects of LINC-PINT overexpression on cellular behaviors of gastric cancer cells were attenuated by miR-21 overexpression. Therefore, LINC-PINT may participate in gastric cancer through the crosstalk with miR-21.     

LncRNA PDCD4-AS1 alleviates triple negative breast cancer by increasing expression of IQGAP2 via miR-10b-5p

ObjectiveMounting evidence demonstrates that long non-coding RNA (lncRNA) is dysregulated in breast cancers. This study was designed to detect the influences and regulatory mechanism of lncRNA PDCD4-AS1 in triple-negative breast cancer (TNBC).MethodsqRT-PCR and Western blot were utilized to investigate the expression levels of PDCD4-AS1, miR-10b-5p and IQGAP2 in TNBC tissues and cells. Online software and luciferase reporter gene system were employed to testify the interactions among these molecules. Loss and gain of function of PDCD4-AS1, miR-10b-5p or IQGAP2 were performed before MTT and colony formation assay, TUNEL staining in addition to Transwell and scratch assays were applied to measure the cell biological functions.ResultsIn this work, PDCD4-AS1 and IQGAP2 were lowly expressed while miR-10b-5p was strongly expressed in TNBC tissues and cells. PDCD4-AS1 or IQGAP2 overexpression effectively attenuated TNBC cell proliferation, migration and invasion, and increased the apoptosis rate, while this effect was abandoned in response to miR-10b-5p mimics transfection. miR-10b-5p bound to IQGAP2 and acted as a downstream target of PDCD4-AS1.ConclusionOur findings identified lncRNA PDCD4-AS1 as a tumor suppressor in TNBC by regulating IQGAP2 expression via miR-10b-5p, giving a novel insight into the regulatory mechanism of PDCD4-AS1 in the pathogenesis of TNBC.     

LncRNA AWPPH and miRNA-21 regulates cancer cell proliferation and chemosensitivity in triple-negative breast cancer by interacting with each other

Long–non-coding RNAs (lncRNA) AWPPH promotes the progression of liver and bladder cancer, indicating its oncogenic role. The current study aimed to explore the involvement of AWPPH in triple-negative breast cancer (TNBC). In the current study, we found that plasma levels of lncRNA AWPPH and microRNA-21 (miRNA-21) were upregulated in patients with TNBC than in healthy controls, and the upregulation of plasma lncRNA AWPPH and miRNA-21 distinguished early-stage patients with TNBC from healthy controls. Plasma levels of lncRNA AWPPH and miRNA-21 were significantly and positively correlated in both patients with TNBC and healthy controls. LncRNA AWPPH and miRNA-21 overexpression led to promoted cancer cells proliferation and improved cancer cell viability under carboplatin treatment, while lncRNA AWPPH small interfering RNA (siRNA) silencing played an opposite role. In addition, miRNA-21 overexpression attenuated the effects of lncRNA AWPPH siRNA silencing on of cancer cell behaviors. LncRNA AWPPH overexpression led to upregulated miRNA-21 in TNBC cells, while miRNA-21 overexpression also led to significantly upregulated lncRNA AWPPH expression. Therefore, lncRNA AWPPH and miRNA-21 may regulate cancer cell proliferation and chemosensitivity in TNBC by interacting with each other.     

Long noncoding RNA SBF2-AS1 promotes colorectal cancer proliferation and invasion by inhibiting miR-619-5p activity and facilitating HDAC3 expression

Evidence, demonstrating long noncoding RNAs (lncRNAs) as critical players in cancer, remains to increase. lncRNA SBF2-AS1 was reported to be involved in several cancers, such as hepatocellular carcinoma. However, the role of SBF2-AS1 in colorectal cancer (CRC) is unknown. We showed lncRNA SBF2-AS1 expression was growing in CRC samples, especially in advanced cases. Accordingly, SBF2-AS1 possesses higher expression in CRC cell lines than in normal cell line. Moreover, SBF2-AS1 high expression indicated a low survival rate. Functionally, SBF2-AS1 knockdown suppressed the proliferation, migration, and invasion of CRC cells. In terms of mechanism, SBF2-AS1 upregulation restrained the activity of miR-619-5p and led to overexpression of HDAC3. Importantly, downregulation of miR-619-5p or HDAC3 overexpression reversed SBF2-AS1-silencing-caused suppression on proliferation and metastasis. Summarily, our findings elucidated a crucial role of SBF2-AS1 as a miR-619-5p sponge, shedding novel light on lncRNA-related prognostics.     

Comprehensive bioinformatics analysis identifies lncRNA HCG22 as a migration inhibitor in esophageal squamous cell carcinoma

Esophageal cancer is one of the most lethal malignancies worldwide, and esophageal squamous cell carcinoma (ESCC) is the dominant histological type. However, the long noncoding RNA (lncRNA) alterations in ESCC have not been elucidated to date. In this study, reliable databases from Gene Expression Omnibus (GEO), which analyzed lncRNA expression in ESCC tumor tissues and adjacent normal tissues were searched, and common differentially expressed lncRNAs and genes were analyzed. Next, cis- trans analysis was performed to predict the underlying relationships between altered lncRNAs and mRNAs, and the lncRNA-mRNA regulatory network was established. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of altered lncRNA-related genes were performed. The promising lncRNA HCG22 was validated by quantitative polymerase chain reaction (qPCR), and clinicopathological data were collected to identify the relationship between lncRNA HCG22 expression level and clinical features. Finally, Transwell assays were performed to explore the biological functions of lncRNA HCG22 in ESCC cells. Two hundred forty-one lncRNAs and 835 mRNAs were observed to be remarkably altered between ESCC tumor tissues and adjacent normal tissues. The lncRNA-mRNA regulatory network showed the coexpression association between lncRNA HCG22 and SPINK7 and ADAMTS12. GO and KEGG analyses showed that HCG22 and ADAMTS12 had potential biological functions in the cell migration of ESCC. The downregulation of lncRNA HCG22 in ESCC tumor tissues was validated by qPCR, and the clinicopathological data showed a noticeable correlation between lncRNA HCG22 expression level and the ESCC differentiational degree and clinical TNM stage. Kaplan-Meier analysis showed that patients with ESCC having low lncRNA HCG22 expression in ESCC tissues had considerably shorter overall survival compared with patients with ESCC having high lncRNA HCG22 expression. Following Transwell assays confirmed the migratory role of lncRNA HCG22 in ESCC cells. In conclusion, lncRNA HCG22 was downregulated in ESCC tissues and can be a migration inhibitor of ESCC cells, and SPINK7 and ADAMTS12 are promising to be the regulatory targets of lncRNA HCG22.     

Silencing of long noncoding RNA LEF1-AS1 prevents the progression of hepatocellular carcinoma via the crosstalk with microRNA-136-5p/WNK1

Long noncoding RNAs (lncRNAs) have been recognized as cancer-associated biological molecules, favoring hepatocellular carcinoma (HCC) progression. This study was conducted to elucidate the effects lncRNA lymphoid enhancer-binding Factor 1 antisense RNA (LEF1-AS1) on the pathological development of HCC, along with the crosstalk involving microRNA-136-5p (miR-136-5p) and with-no-K (lysine) kinase 1 (WNK1). The study recruited primary HCC tissues and their corresponding nonneoplastic liver tissues. The gain- and loss-of-function studies were performed in HCC cells HuH-7 and tumor xenografts in nude mice. The dual luciferase reporter gene assay system, RNA pull-down, and radioimmunoprecipitation assays were applied to detect their interactions among lncRNA LEF1-AS1, miR-136-5p, and WNK1. 5-Ethynyl-2′-deoxyuridine staining, scratch test, Transwell assays, and in vitro tube formation assays were conducted to examine HCC cell proliferation, migration, and invasion and HUVEC angiogenesis. HCC tissues and cells contained high lncRNA LEF1-AS1 expression. LncRNA LEF1-AS1 upregulation triggered markedly increased HCC cell proliferation, migration, and invasion and human umbilical vein endothelial cell angiogenesis. In vivo silencing lncRNA LEF1-AS1 resulted in reduced tumor cell vitality and matrix metalloproteinase-9 and the vascular endothelial growth factor expression. Additionally, the role of lncRNA LEF1-AS1 was found to be largely dependent on WNK1. Association of lncRNA LEF1-AS1 with WNK1 blocked the inhibitory effect of miR-136-5p on WNK1, which was confirmed by in vivo experiments. Altogether, our results revealed an important role of lncRNA LEF1-AS1 in regulating the HCC progression by regulating WNK1, providing a potential biomarker for the therapeutic modalities regarding HCC.     

Overexpression of long noncoding RNA SLC26A4-AS1 inhibits the epithelial–mesenchymal transition via the MAPK pathway in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is recognized as one of the most prevalent types of thyroid cancer with poor prognosis. Long noncoding RNA (lncRNA) has undergone an intensive study for their involvement in tumor treatment. This study intends to unravel the association of lncRNA SLC26A4-AS1 with PTC. Initially, PTC-related expression profiling data (GSE33630) was utilized to screen differentially expressed lncRNAs in PTC and the underlying mechanisms involved with the mitogen-activated protein kinase (MAPK) pathway. Moreover, PTC tumor tissues and paracancerous tissues were arranged to determine expressions of TP53, SLC26A4-AS1, and genes related to epithelial–mesenchymal transition (EMT) and the MAPK pathway. Furthermore, SLC26A4-AS1 was overexpressed or underexpressed and JNK was underexpressed through cell transfection to examine the effect of SLC26A4-AS1 on PTC via MAPK pathway. Besides, tumor formation in nude mice was used to verify the fore experiment. LncRNA SLC26A4-AS1 regulating TP53 had the potential to participate in PTC by regulating the MAPK pathway. SLC26A4-AS1 was expressed poorly in PTC. Notably, SLC26A4-AS1 elevated E-cadherin expression while it reduced that of ERK and Vimentin. In addition, the overexpression of SLC26A4-AS1 inactivated the MAPK pathway by promoting TP53 and decreased cell migration, proliferation, and invasion. In addition to all these effects, the overexpression of SLC26A4-AS1 promoted apoptosis of TPC-1 cells. Additionally, the overexpression of lncRNA SLC26A4-AS1 reduced xenograft tumor volume in nude mice. Furthermore, the effect of SLC26A4-AS1 overexpression was found to be promoted after the MAPK pathway inactivation. Taken together, the overexpression of lncRNA SLC26A4-AS1 coffered anti-oncogenic effects on PTC through the inactivation of the MAPK pathway.     

Long noncoding RNA SOX21-AS1 promotes cervical cancer progression by competitively sponging miR-7/VDAC1

Growing evidence has shown that long noncoding RNAs (lncRNAs) play crucial roles in cervical cancer. Dy000sregulation of lncRNA SOX21 antisense RNA 1 (SOX21-AS1) has been reported in several tumors. However, its expression pattern and potential biological function in cervical cancer (CC) have not been investigated. In this study, we first reported that SOX21-AS1 expression was significantly upregulated in both CC tissues and cell lines. High expression of SOX21-AS1 was found to be significantly correlated with Federation of Gynecology and Obstetrics (FIGO) stage, lymph node metastasis and depth of cervical invasion. Further clinical assay confirmed that high SOX21-AS1 expression was associated with shorter overall survival and could be used as a potential prognostic biomarker for CC patients. Functional investigation showed that knockdown of SOX21-AS1 suppressed CC cells proliferation, migration, and invasion, as well as epithelial to mesenchymal transition progress. Furthermore, our data showed that microRNA-7 (miR-7) interacted with SOX21-AS1 by directly targeting the miRNA-binding site in the SOX21-AS1 sequence, and quantitative real-time polymerase chain reaction results showed overexpression of SOX21-AS1 decreased the levels of miR-7 in CC cells. Moreover, we confirmed that miR-7 directly targeted the 3′-untranslated region of voltage dependent anion channel 1 (VDAC1). Final in vitro assay suggested that in CC cells with SOX21-AS1, VDAC1 overexpression resulted in an increase of cell proliferation, migration, and invasion. Overall, our findings illuminate how SOX21-AS1 formed a regulatory network to confer an oncogenic function in CC and SOX21-AS1 could be regarded as an efficient therapeutic target and potential biomarker for CC patients.     

Long non-coding RNA OIP5-AS1 promotes pancreatic cancer cell growth through sponging miR-342-3p via AKT/ERK signaling pathway

Opa-interacting protein 5 antisense RNA 1 (OIP5-AS1), a long non-coding RNA (lncRNA), has been reported to link with the progression of some cancers. However, its biological functions and underlying molecular mechanisms in pancreatic cancer are largely unknown. The aim of this study was to investigate the role of lncRNA OIP5-AS1 in pancreatic cancer. Quantitative real-time PCR analysis revealed that OIP5-AS1 is highly expressed in pancreatic cancer tissues versus adjacent non-tumor tissues. In vitro functional assays showed that downregulation of OIP5-AS1 or overexpression of miR-342-3p inhibited the proliferation, decreased Ki67 expression, and induced cell cycle arrest in pancreatic cancer cells. The expression of cyclinD1, CDK4, and CDK6 was decreased by knockdown of OIP5-AS1. Moreover, we found that OIP5-AS1 acted as a miR-342-3p sponge to suppress its expression and function. Dual-luciferase assay confirmed the interaction of OIP5-AS1 and miR-342-3p and verified anterior gradient 2 (AGR2) as a direct target of miR-342-3p. Results showed that depletion of miR-342-3p abolished the inhibitory effects of OIP5-AS1 knockdown on pancreatic cancer cell growth. The expression of Ki67, AGR2, cyclinD1, CDK4, CDK6, p-AKT, and p-ERK1/2 was reversed by silencing of miR-342-3p in pancreatic cancer cells with OIP5-AS1 knockdown. Further, knockdown of OIP5-AS1 suppressed tumor growth in a xenograft mouse model of pancreatic cancer. OIP5-AS1 induced pancreatic cancer progression via activation of AKT and ERK signaling pathways. Therefore, we demonstrate that OIP5-AS1 functions as oncogene in pancreatic cancer and its downregulation inhibits pancreatic cancer growth by sponging miR-342-3p via targeting AGR2 through inhibiting AKT/ERK signaling pathway.