circRACGAP1 Promotes Proliferation of Non-Small Cell Lung Cancer Cells through the miR-1296/CDK2 Pathway.

Circular RNAs (circRNAs) have played an essential role in cancer development. This study aimed to illustrate the impact and potential mechanism of circRACGAP1 action in NSCLC development. The expression patterns of circRACGAP1, miR-1296, and CDK2 in NSCLC tissues and cell lines were analysed by RT-qPCR. The function of circRACGAP1 in NSCLC cell proliferation and apoptosis was investigated using the CCK-8 assay, flow cytometry, TUNEL staining, and Western blot. The interaction among circRACGAP1, miR-1296, and CDK2 was clarified by dual-luciferase reporter assay while the correlation was confirmed by the Pearson correlation coefficient. The expression of circRACGAP1 and CDK2 was up-regulated in NSCLC tissues, while the expression of miR-1296 was down-regulated. Cell function studies further revealed that circRACGAP1 could promote NSCLC cell proliferation, accelerate the cell cycle process, up-regulate B-cell lymphoma 2 (Bcl2) expression, and down-regulate Bcl2-associated X (Bax) expression. miR-1296 was identified as a downstream target to reverse circRACGAP1-mediated cell proliferation. miR-1296 directly targeted the 3'-UTR of CDK2 to regulate proliferation and apoptosis of NSCLC cells. Additionally, the dual-luciferase reporter assay and Pearson correlation coefficient analysis proved that circRACGAP1 acted in NSCLC cells by negatively regulating miR-1296 expression and positively regulating CDK2 expression. In summary, our study revealed that circRACGAP1 promoted NSCLC cell proliferation by regulating the miR-1296/CDK2 pathway, providing potential diagnostic and therapeutic targets for NSCLC.

LncRNA GAS6-AS1 facilitates tumorigenesis and metastasis of colorectal cancer by regulating TRIM14 through miR-370-3p/miR-1296-5p and FUS.

BACKGROUND: Long non-coding RNAs (lncRNAs) are essential regulators of tumorigenesis and the development of colorectal cancer (CRC). Here, we aimed to investigate the role of lncRNA GAS6-AS1 in CRC and its potential mechanisms. METHODS: Bioinformatics analyses evaluated the level of GAS6-AS1 in colon cancer, its correlation with clinicopathological factors, survival curve and diagnostic value. qRT-PCR were performed to detect the GAS6-AS1 level in CRC samples and cell lines. The CCK8, EdU, scratch healing, transwell assays and animal experiments were conducted to investigate the function of GAS6-AS1 in CRC. RNA immunoprecipitation (RIP) and dual-luciferase reporter gene analyses were carried out to reveal interaction between GAS6-AS1, TRIM14, FUS, and miR-370-3p/miR-1296-5p. RESULTS: GAS6-AS1 was greatly elevated in CRC and positively associated with unfavorable prognosis of CRC patients. Functionally, GAS6-AS1 positively regulates CRC proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) in vitro and induces CRC growth and metastasis in vivo. Moreover, GAS6-AS1 exerted oncogenic function by competitively binding to miR-370-3p and miR-1296-5p, thereby upregulating TRIM14. Furthermore, we verified that GAS6-AS1 and TRIM14 both interact with FUS and that GAS6-AS1 stabilized TRIM14 mRNA by recruiting FUS. Besides, rescue experiments furtherly demonstrated that GAS6-AS1 facilitate progression of CRC by regulating TRIM14. CONCLUSION: Collectively, these findings demonstrate that GAS6-AS1 promotes TRIM14-mediated cell proliferation, migration, invasion, and EMT of CRC via ceRNA network and FUS-dependent manner, suggesting that GAS6-AS1 could be utilized as a novel biomarker and therapeutic target for CRC.

Improved delivery of miR-1296 loaded cationic nanoliposomes for effective suppression of triple negative breast cancer.

Nowadays, microRNA is considered an attractive strategy for the effective treatment of cancer. A significant delivery of microRNA for cancer therapy remains a significant obstacle to target cancer cells. The restoring microRNA-1296 (miR-1296) has immense therapeutic efficacy in triple-negative breast cancer (TNBC). TNBC is an aggressive subtype of breast tumors with the progression of malignant transformation. This study aimed to develop a cationic nanoliposome that can serve as a miR-1296 carrier and studied its efficiency in TNBC. The efficacy of miR-1296 liposomes was evaluated on its apoptotic effect, cellular uptake, and potential chemotherapy sensitization in the TNBC cell line (MDA-MB-231). For in vitro viability study, the apoptotic effect was performed to validate protein expression using Alamar blue kit and western blot. The transfection of miR-1296 into TNBC cells was also investigated using cisplatin as a TNBC resistance drug. The fluorescent miR-1296-cy3 liposome was used for cellular uptake study. The miR-liposome was successfully prepared with a particle size of 123.6 ± 1.3 nm and encapsulation efficiency of 94.33%. A dose of 0.5 uM has significantly reduced the viability of MDA-MB-231 to be 33.45%±5.29 (P < 0.001). This result was validated by down-expression of CCND1, and PARP1, the miR-1296 receptor, and apoptosis marker. The image of the miR-1296-cy3 liposome showed cytoplasmic intracellular localization. It was found high sensitization of TNBC cell line for miR-1296 liposome compared to cisplatin (P < 0.001). Future in vivo research may answer questions concerning safety and stability. This study demonstrates that miR-191 liposomes may have promising clinical applications for TNBC therapy.

MicroRNA-1296-5p suppresses the proliferation, migration, and invasion of human osteosarcoma cells by targeting NOTCH2.

Osteosarcoma (OS) is a highly aggressive bone tumor with a poor prognosis. MicroRNAs are revealed to exerts essential roles in the carcinogenesis and tumor invasion of OS. But, the function of miR-1296-5p and its related mechanism in OS progression have not yet been studied. This study discovered the levels of miR-1296-5p in OS and corresponding noncancerous tissues, and we demonstrated that miR-1296-5p level was markedly downregulated in tumor specimens as compared with nontumor tissues. In addition, we discovered that miR-1296-5p was also underexpressed in OS cells compared with the hFOB1.19 osteoblast cells. Interestingly, the reduced expression of miR-1296-5p was confirmed to associated with large tumor size, advanced tumor stages, and distance metastasis, respectively. Patients with OS low-expressing miR-1296-5p showed a prominent shorter survival. In addition, gain-of-function assays verified that miR-1296-5p overexpression remarkably repressed OS cell proliferation, migration, and invasion. Conversely, depletion of miR-1296-5p facilitated the growth and mobility of OS cells. Notably, miR-1296-5p inversely modulated notch receptor 2 (NOTCH2) in OS cells. The level of NOTCH2 messenger RNA was negatively correlated with miR-1296-5p level in OS samples. NOTCH2 knockdown markedly suppressed the abilities of MG-63 cell proliferation and mobility. More importantly, the restoration of NOTCH2 prominently rescued miR-1296-5p-induced tumor-suppressive effects on MG-63 cells. In conclusion, our study identified the reduced expression of miR-1296-5p, which contributed to OS progression. miR-1296-5p might be a promising prognostic marker and therapeutic target in OS.

miR-1296-5p decreases ERBB2 expression to inhibit the cell proliferation in ERBB2-positive breast cancer.

BACKGROUND: The tumor suppressive role of miR-1296 is observed in triple negative breast cancer (TNBC). However, the effect of miR-1296-5p in ERBB2-positive breast cancers remains obscure. METHODS: Whether ERBB2 was the target gene of the miR-1296-5p was predicted by online software, and determined by dual-luciferase activity assay. miR-1296-5p expression levels were determined in breast cancer samples (114 breast cancer tissues and 30 adjacent normal tissues) by using qRT-PCR. The effect of miR-1296-5p and inhibition of ERBB2/mTORC1 signaling on the downstream target was assessed by Western blot. SK-BR-3 and BT-474 breast cancer cell line was transfected with miR-1296-5p mimic after which cell proliferation and apoptosis were determined by the clonogenic assay and the flow cytometry system, respectively. In addition, the chemotherapeutic drug sensitivity of SK-BR-3 and BT-474 cells transfected with miR-1296-5p mimic were determined by MTT assay. RESULTS: The luciferase assay carrying ERBB2 3'-untranslated region-based reporters expressed in SK-BR-3 and BT-474 cells suggested that ERBB2 was the target gene of miR-1296-5p. MiR-1296-5p was significantly decreased in breast cancer tissues compared to adjacent normal tissues. Moreover, it was declined in ERBB2-positive breast cancer samples compared with that in ERBB2-negative breast cancer tissues. Overexpressed miR-1296-5p reduced its target protein level and mTORC1/S6 activation, inhibited the proliferation of ERBB2-positive breast cancer cells and sensitized these cells to cisplatin and 5-fluorouracil-induced apoptosis. CONCLUSIONS: Our findings suggest that miR-1296-5p is involved in the regulation of proliferation in breast cancer cells via targeting ERBB2/mTORC1 signaling pathway.

Decreased AGGF1 facilitates the progression of placenta accreta spectrum via mediating the P53 signaling pathway under the regulation of miR-1296-5p.

Placenta accreta spectrum (PAS), an emerging health issue worldwide, is the major causative factor of maternal morbidity and mortality in modern obstetrics, but limited studies have contributed to our understanding of the molecular biology of PAS. This study addressed the expression of AGGF1 and its specific role in the etiology of PAS. The expression of AGGF1 in the placentas of PAS was determined by quantitative PCR, western blot and immunohistochemistry. CCK-8 assay, wound healing assay, Transwell invasion assay and flow cytometry assay were performed to monitor cell proliferation, migration, invasion and apoptosis. The interaction between miR-1296-5p and AGGF1 was detected by dual-luciferase reporter gene assay. Results showed that the mRNA and protein expression of AGGF1 was decremented in placental tissues of PAS patients, compared with samples from women with placenta previa and normal pregnant women. Downregulation of AGGF1 promoted cell proliferation, invasion and migration, inhibited apoptosis in vitro, decreased P53 and Bax expression, and simultaneously increased Bcl-2 expression, whereas overexpression of AGGF1 had the opposite results. Additionally, the dual-luciferase assay confirmed AGGF1 as a target gene of miR-1296-5p in placental tissues of PAS. Particularly, miR-1296-5p fostered HTR8/SVneo cell proliferation, invasion, repression of apoptosis and regulation of P53 signaling axis by downregulating AGGF1 expression. Collectively, our study accentuated that downregulation of placental AGGF1 promoted trophoblast over-invasion by mediating the P53 signaling pathway under the regulation of miR-1296-5p.

Silencing of circUSPL1 represses breast cancer progression by targeting miR-1296-5p/MTA1 axis.

BACKGROUND: The effect of circular RNAs (circRNAs) is widely studied in various human cancers, including breast cancer (BC). Herein, circUSPL1 has been recognized as a new regulator for BC progression. However, the detailed biological function and molecular mechanism of circUSPL1 in BC remain vague. METHODS: The expression level of circUSPL1, miR-1296-5p and metastasis associated 1 (MTA1) was examined by quantitative reverse transcription PCR. BC cell proliferation, migration, invasion, apoptosis and aerobic glycolysis were analyzed by colony formation assay, 5-ethynyl-2'-deoxyuridine assay, wound healing assay, transwell assay, flow cytometry and glycolysis corresponding kits, respectively. The protein level of Bcl-2, Bax, HK2, GLUT1 and MTA1 was evaluated by western blot analysis. The relationship of miR-1296-5p and circUSPL1 or MTA1 was affirmed using dual-luciferase reporter or RIP assays. A murine xenograft model was conducted to analyze the tumor growth in vivo. RESULTS: CircUSPL1 and MTA1 expression level was increased, but miR-1296-5p was particularly reduced in BC tissues and cells. CircUSPL1 deficiency significantly inhibited BC cell proliferation, migration, invasion, glycolysis, and promoted cell apoptosis. In addition, circUSPL1 directly targeted miR-1296-5p, and downregulation of miR-1296-5p eliminated the inhibitory action of circUSPL1 knockdown. Additionally, overexpression of miR-1296-5p repressed cell malignant properties, while the suppressive effects were overturned by MTA1 elevation. Lastly, silencing of circUSPL1 inhibited tumor growth by sponging miR-1296-5p and regulating MTA1. CONCLUSION: CircUSPL1 deficiency repressed BC cell malignant phenotypes through reducing MTA1 via targeting miR-1296-5p, which might provide a theoretical basis for BC treatment.

Identification of circRNA-miRNA-mRNA network in luminal breast cancers by integrated analysis of microarray datasets.

Introduction: Circular RNAs (circRNAs) regulatory network is important in human cancer. We, therefore, mapped the regulatory networks driven by circRNA in luminal-subtype breast cancer. Methods: Breast cancer-related microarray datasets from GEO database were analyzed for the differentially expressed circRNAs, miRNAs, and mRNAs. The potential downstream RNAs were collected using Circular RNA Interactome or Targetscan database. Protein-protein interaction (PPI) analysis was performed for the filtered genes to identify hub genes. The functions were annotated by the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. CircRNA-miRNA-mRNA networks were mapped using Cytoscape software. Hsa_circ_0086735-miR-1296-5p-STAT1 axis was used for verification. The expression levels of hsa_circ_0086735, miR-1296-5p, and STAT1 mRNA were confirmed by qRT-PCR in luminal-subtype tissues and cell lines. The interactions among them were verified by Luciferase reporter assay and RNA pull-down assay. Cell proliferation and apoptosis were assayed. Overall and distant metastasis-free survival was analyzed. Results: A total of 70 genes were finally targeted and enriched in multi-process and multi-pathway. Networks containing 96 circRNA-miRNA-mRNA axes were constructed. Hsa_circ_0086735 and STAT1 mRNA was upregulated in luminal breast cancer, while miR-1296-5p was downregulated. Hsa_circ_0086735-miR-1296-5p-STAT1 axis promotes breast cancer progression and contributes to tamoxifen resistance. High hsa_circ_0086735 was associated with poor overall and distant metastasis-free survival. Discussion: This study identified the hsa_circ_0086735-miR-1296-5p-STAT1 as an important regulatory axis in luminal-subtype breast cancer, aiding to determine potential therapeutic targets.

hsa_circ_0000519 promotes the progression of lung adenocarcinoma through the hsa-miR-1296-5p/DARS axis.

Emerging research indicates that circRNAs serve a crucial role in occurrence and development of cancers. This study aimed to uncover the biological role of hsa_circ_0000519 in the progression of LUAD (lung adenocarcinoma). hsa_circ_0000519 was identified by bioinformatic analysis, and its differential expression was validated in LUAD tissues and cell lines. CCK8, colony formation, wound healing, transwell assays, and xenograft tumor models were used to observe the biological functions of hsa_circ_0000519. FISH, RIP, dual luciferase reporter assays, and recovery experiments were implemented to explore the underlying mechanisms of hsa_circ_0000519. hsa_circ_0000519 was significantly upregulated in LUAD tissues and cell lines. The expression of hsa_circ_0000519 was positively correlated with T grade and TNM stage in patients with LUAD. Downregulation of hsa_circ_0000519 remarkably reduced cell proliferation, migration, invasion in vitro, and tumor growth in vivo. Mechanistic investigation demonstrated that hsa_circ_0000519 directly sponged hsa-miR-1296-5p to reduce its repressive impact on DARS as well as activate the PI3K/AKT/mTOR signaling pathway. The malignant phenotypes of LUAD cells induced by upregulation of hsa_circ_0000519 could be rescued by hsa-miR-1296-5p overexpression or knockdown of DARS. In conclusion, hsa_circ_0000519 promotes LUAD progression through the hsa-miR-1296-5p/DARS axis and may be expected as a novel biomarker and therapeutic for LUAD.

Circular RNA circ_0048764 promotes the development of breast cancer by regulating microRNA-1296-5p/tripartite motif containing 14 axis.

Breast cancer (BC) is one of the leading causes of cancer-related deaths in females. Circular RNA (circRNA), as reported, is involved in the progression of BC. This work focuses on clarifying the biological function of circ_0048764 in BC and its hidden mechanism. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expressions of circ_0048764, microRNA-1296-5p (miR-1296-5p), and tripartite motif containing 14 (TRIM14) in BC tissues and cell lines. Besides, the status of proliferation, migration, invasion and apoptosis of BC cells was probed by cell counting kit-8 (CCK-8), EdU, transwell and flow cytometry assays. Western blot was adopted to examine the level of TRIM14 protein in BC cells. In addition, dual-luciferase reporter gene assay and RNA immunoprecipitation (RIP) assay were conducted to corroborate the targeting relationships between miR-1296-5p and circ_0048764 or TRIM14. It was revealed that circ_0048764 expression was remarkably up-regulated in BC tissues and cells, and circ_0048764 expression was associated with TNM stage and tumor size. Functionally, overexpression of circ_0048764 significantly promoted BC cell proliferative, migrative and invasive abilities and inhibited apoptosis, while circ_0048764 knockdown exerted the opposite effects. Mechanistically, circ_0048764 directly targeted miR-1296-5p and could negatively modulate its expression in BC cells. Besides, miR-1296-5p could reverse the influence of circ_0048764 on BC viability, migration, invasion and apoptosis. Moreover, TRIM14 was confirmed to be a downstream target of miR-1296-5p. Circ_0048764 positively regulated TRIM14 expression in BC cells via targeting miR-1296-5p. Collectively, it is concluded that circ_0048764 promotes the development of BC via modulating the miR-1296-5p/TRIM14 axis.

Hsa_circ_0017639 regulates cisplatin resistance and tumor growth via acting as a miR-1296-5p molecular sponge and modulating sine oculis homeobox 1 expression in non-small cell lung cancer.

Cisplatin (DDP)-induced chemoresistance is an important reason for the failure of non-small cell lung cancer (NSCLC) treatment. Circular RNAs (circRNAs) participate in the chemoresistance of diverse cancers. However, the function of hsa_circ_0017639 (circ_0017639) in the DDP resistance of NSCLC is unclear. Forty-one NSCLC samples (21 DDP-resistant samples and 20 DDP-sensitive samples) were utilized in the research. The relative expression levels of some genes were determined by real-time quantitative polymerase chain reaction (RT-qPCR). 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay for half-maximal inhibitory concentration (IC50) value of DDP and cell viability, colony formation and 5-ethynyl-2'-deoxyuridine (EDU) assays for cell proliferation, flow cytometry assay for cell apoptosis, transwell assay for cell invasion and wound-healing assay for cell migration were performed. The regulation mechanism of circ_0017639 was demonstrated by a dual-luciferase reporter assay. We observed higher levels of circ_0017639 in DDP-resistant NSCLC samples and cells. Functionally, circ_0017639 silencing decreased tumor growth and elevated DDP sensitivity in vivo and induced apoptosis, repressed proliferation, invasion, and migration of DDP-resistant NSCLC cells in vitro. Mechanically, circ_0017639 modulated sine oculis homeobox 1 (SIX1) expression via sponging microRNA (miR)-1296-5p. Also, miR-1296-5p inhibitor restored circ_0017639 knockdown-mediated impacts on cell DDP resistance in DDP-resistant NSCLCs. Furthermore, SIX1 overexpression counteracted the inhibiting impact of miR-1296-5p upregulation on DDP resistance and malignant phenotypes of DDP-resistant NSCLC cells. In conclusion, circ_0017639 conferred DDP resistance and promoted tumor growth via elevating SIX1 expression through sequestering miR-1296-5p in NSCLC, providing a new mechanism for understanding the chemoresistance and progression of NSCLC.

microRNA-1296 Inhibits Glioma Cell Growth by Targeting ABL2.

Aberrant expression of microRNAs (miRNAs) has been reported to play a role in tumorigenesis. Dysfunction of miR-1296 was found in a variety of cancers, however, the function of miR-1296 in the progression of glioma remains largely understood. Here, our results showed that miR-1296 was significantly down-regulated in glioma tissues and cell lines. Decreased expression of miR-1296 was associated with the tumor size, WHO grade and karnofsky performance scale (KPS) of glioma patients. Low expression of miR-1296 was significantly correlated with the shorter 5-year overall survival of glioma patients. Overexpression of miR-1296 inhibited the proliferation, colony formation, migration and induced apoptosis of glioma cells. MiR-1296 was found to bind the 3'-untranslated region (UTR) of ABL proto-oncogene 2 (ABL2) and subsequently repressed both the mRNA and protein expression of ABL2. ABL2 was overexpressed in glioma tissues and inversely correlated with that of miR-1296. Ectopic expressed ABL2 could reverse the inhibitory effects of miR-1296 on glioma cell proliferation. Our results illustrated the novel tumor-suppressive function of miR-1296 in glioma via repressing ABL2, suggesting a potential application of miR-1296 in the treatment of glioma.

Circ_0000520 contributes to triple-negative breast cancer progression through mediating the miR-1296/ZFX axis.

BACKGROUND: Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with a high incidence of local recurrence and metastasis. Circular RNAs (circRNAs) are implicated in the pathomechanism of TNBC. Here, we investigated the function of circ_0000520 in TNBC and its associated mechanism. METHODS: Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot assay were used to measure RNA and protein expression. Cell proliferation was analyzed by cell counting kit-8 (CCK8) assay, flow cytometry and colony formation assay. Cell apoptosis was assessed by flow cytometry. Cell migration ability was analyzed by transwell migration and wound healing assays. Transwell invasion assay was conducted to analyze the invasion ability. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay, and RNA-pulldown assay were performed to verify the interaction between microRNA-1296 (miR-1296) and circ_0000520 or zinc finger protein X-linked (ZFX). Xenograft mice model was established to analyze the role of circ_0000520 in xenograft tumor growth in vivo. RESULTS: Circ_0000520 expression was upregulated in TNBC tissues and cell lines. Circ_0000520 knockdown suppressed the proliferation, migration, and invasion whereas induced the apoptosis of TNBC cells. miR-1296 was verified as a target of circ_0000520, and circ_0000520 silencing-mediated suppressive effects on the malignant potential of TNBC cells were partly overturned by miR-1296 knockdown. miR-1296 interacted with the 3' untranslated region (3'UTR) of ZFX, and ZFX overexpression partly reversed miR-1296 overexpression-mediated effects in TNBC cells. Circ_0000520 absence reduced ZFX expression by upregulating miR-1296 in TNBC cells. Circ_0000520 silencing suppressed xenograft tumor growth in vivo. CONCLUSIONS: Circ_0000520 contributed to TNBC development by binding to miR-1296 to induce ZFX expression.

Blocking circ_0000520 Suppressed Breast Cancer Cell Growth, Migration and Invasion Partially via miR-1296/SP1 Axis Both in vitro and in vivo.

BACKGROUND: Breast cancer (BCa) is an overwhelming malignant tumor mainly in women globally. Circular RNAs (circRNAs) are a special type of noncoding RNAs involved in competing endogenous RNA (ceRNA) network, a classic molecular mechanism of the tumorigenesis of human cancers, including BCa. Here, we intended to explore the role and mechanism of hsa_circ_0000520 (circ_0000520) in BCa cells. METHODS: Expression of circ_0000520, miRNA-1296-5p (miR-1296) and specificity protein 1 (SP1) was measured by real time-quantitative PCR and Western blotting. Cell growth was measured by cell counting kit-8, colony formation assay and flow cytometry method. Cell migration and invasion were assessed by transwell assays and Western blotting. Tumor growth was determined by xenograft models. The direct interaction among circ_0000520, miR-1296 and SP1 was confirmed by dual-luciferase reporter assay and RNA pull-down assay. RESULTS: circ_0000520 was upregulated in BCa tumors and cell lines (T47D, MCF7, MDA-MB-231, BT549, and SKBR3), and circ_0000520 high expression was associated with poor overall survival. Blocking circ_0000520 suppressed cell viability, colony formation, migration and invasion, but promoted cell cycle arrest and apoptosis rate in MDA-MB-231 and MCF7 cells. circ_0000520 could directly regulate miR-1296 expression, and SP1 was a novel target for miR-1296. Moreover, the anti-tumor role of circ_0000520 silencing was abrogated by miR-1296 downregulation or SP1 restoration. Notably, tumor growth of MDA-MB-231 cells in mice was restrained by circ_0000520 deletion. CONCLUSION: circ_0000520 knockdown could suppress cell growth, migration and invasion both in vitro and in vivo through regulating miR-1296/SP1 pathway.

Circ_0000517 Contributes to Hepatocellular Carcinoma Progression by Upregulating TXNDC5 via Sponging miR-1296-5p.

BACKGROUND: Circular RNAs (circRNAs) function as essential regulators in diverse human cancers, including hepatocellular carcinoma (HCC). However, the function of circ_0000517 in HCC was unknown. We aimed to explore the roles and mechanisms of circ_0000517 in HCC. MATERIALS AND METHODS: The levels of circ_0000517, RPPH1 mRNA and microRNA-1296-5p (miR-1296-5p) were measured using quantitative real-time polymerase chain reaction (qRT-PCR). The characteristics of circ_0000517 were explored by RNase R digestion and actinomycin D assays. Cell proliferation was evaluated by Cell Counting Kit-8 (CCK-8) and colony formation assays. Cell cycle process and cell apoptosis were analyzed by flow cytometry analysis. The function of circ_0000517 in vivo was explored by a murine xenograft model. The association between miR-1296-5p and circ_0000517 or thioredoxin domain containing 5 (TXNDC5) was determined by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. The protein level of TXNDC5 was detected by Western blot assay. RESULTS: Circ_0000517 was upregulated in HCC tissues and cells. Silencing of circ_0000517 suppressed HCC cell viability and colony formation and promoted cell cycle arrest and apoptosis in vitro and hampered tumor growth in vivo. MiR-1296-5p was a target of circ_0000517 and the effects of circ_0000517 silencing on HCC cell viability, cell cycle, colony formation and apoptosis were abolished by miR-1296-5p inhibition. TXNDC5 functioned as a target gene of miR-1296-5p, and the inhibitory effect of miR-1296-5p on HCC cell progression was rescued by TXNDC5 overexpression. Moreover, circ_0000517 promoted TXNDC5 expression via targeting miR-1296-5p. CONCLUSION: Circ_0000517 accelerated HCC progression by upregulating TXNDC5 through sponging miR-1296-5p.

The tumor-suppressive function of miR-1296-5p by targeting EGFR and CDK6 in gastric cancer.

We aimed to confirm the role of miR-1296-5p in gastric cancer and to identify its target genes. The expression of miR-1296-5p was measured in gastric cancer tissues and cell lines. The function of miR-1296-5p was examined by the overexpression and inhibition of its expression in typical gastric cell lines as well as SGC-7901 and MGC-803 cells. The targets of miR-1296-5p were identified by a luciferase activity assay. We found that miR-1296-5p was down-regulated in gastric cancer tissue and cell lines, and low expression levels of miR-1296-5p were associated with advanced clinical stage. Moreover, miR-1296-5p inhibited cell proliferation, migration, and invasion in SGC-7901 and MGC-803 cells. Then, we identified CDK6 and EGFR as novel targets of miR-1296-5p by a luciferase activity assay. Furthermore, the overexpression of miR-1296-5p suppressed the expression of CDK6 and EGFR. Our results indicated a tumor-suppressive role of miR-1296-5p through the translational repression of oncogenic CDK6 and EGFR in gastric cancer.