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Accumulating studies have demonstrated the important role of circular RNAs (circRNAs) in the progression of different human tumors, including non-small-cell lung cancer (NSCLC). The purpose of this study was to deeply study the function and mechanism of circ_0017956 in NSCLC. Real-time quantitative polymerase chain reaction (RT-qPCR) was applied to detect the expression of circ_0017956, microRNA-758-3p (miR-758-3p), and Forkhead Box P4 (FOXP4). Western blot was performed to determine the protein levels. Cell proliferation was examined by cell counting kit-8 (CCK-8) assay and 5-ethynyl-2'-deoxyuridine (EdU) assay. Flow cytometry was used to evaluate the apoptosis of NSCLC cells. Transwell assay was applied to detect cell migratory and invasive capacities. The angiogenesis ability was evaluated by tube formation experiment. The target relationship between miR-758-3p and circ_0017956 or FOXP4 was confirmed by dual-luciferase reporter assay. Animal experiment was conducted to assess the effect of circ_0017956 in vivo. Circ_0017956 and FOXP4 were upregulated, while miR-758-3p was downregulated in NSCLC tissues and cells. Silencing of circ_0017956 significantly suppressed cell proliferation, migration, invasion, and angiogenesis, but promoted cell apoptosis in NSCLC cells. Mechanically, circ_0017956 functioned as a sponge for miR-758-3p and miR-758-3p could directly interact with FOXP4. Moreover, silencing of miR-758-3p or overexpression of FOXP4 could overturn the anticancer influence of circ_0017956 interference on NSCLC cells. Besides that, circ_0017956 knockdown hindered tumor growth in vivo. Altogether, circ_0017956 promoted the progression of NSCLC by regulating FOXP4 through sponging miR-758-3p., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

MicroRNAs (miRNAs) belong to the subgroup of small noncoding RNAs, which typically serve as important gene regulators to participate in different biological events, such as tumor cell growth and apoptosis. Recent studies indicated microRNA-4651 (miR-4651) was involved in hepatocellular carcinoma (HCC) progression. The certain role of miRNA-4651 during the progression of HCC, however, remains unclear. Herein, we investigated the mRNA expression level of miR-4651 in HCC tissues and HCC cell lines and found miR-4651 was noticeably down-regulated compared with the normal liver tissues and QSG-7701 cell line, respectively. Then, miR-4561 overexpression obviously repressed the proliferation and promoted apoptosis in two HCC cell lines. Interestingly, we further identified that miR-4561 could directly interact with FOXP4 in HCC cells by using bio-informatic method and report assay. Moreover, forced expression of FOXP4 showed an opposite effect compared with miR-4561 in HCC cell lines. Hence, our findings strongly indicated that miR-4561 regulated the HCC cell growth and apoptosis mainly through targeting the FOXP4 genes. Clinically, the miR-4561/FOXP4 axis might be a potential target for therapeutic application of HCC patient treatment., (© 2020 The Author(s).)

In recent years, circular RNAs (circRNAs) have been identified to be essential regulators of various human cancers. However, knowledge of the functions of circRNAs in prostate cancer remains very limited. The correlation between circABCC4 and human cancer is largely unknown. This study aims to investigate the biological functions of circABCC4 in prostate cancer progression and illustrate the underlying mechanism. We found that circABCC4 was remarkably up-regulated in prostate cancer tissues and cell lines and promoted FOXP4 expression by sponging miR-1182 in prostate cancer cells. CircABCC4 knockdown markedly suppressed prostate cancer cell proliferation, cell-cycle progression, migration and invasion in vitro. Furthermore, silencing of the circRNA also delayed tumor growth in vivo. Taken together, our findings indicated that circABCC4 facilitates the malignant behaviour of prostate cancer by promoting FOXP4 expression through sponging of miR-1182. The circABCC4-miR-1182-FOXP4 regulatory loop may be a promising therapeutic target for prostate cancer intervention., (© 2019 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)

MicroRNAs are noncoding RNAs of 21 to 23 nucleotides in length that play important roles in almost all biological pathways. The roles of microRNA-299-3p in the development and progression of oral squamous cell carcinoma remain unclear. Expression level of microRNA-299-3p in oral squamous cell carcinoma cell lines was analyzed. Then, the effects of microRNA-299-3p on oral squamous cell carcinoma cell proliferation and migration were investigated. Moreover, bioinformation algorithm and Western blot were conducted to explore whether forkhead box P4 was a direct target of miR-299-3p. We showed that microRNA-299-3p expression was significantly reduced in oral squamous cell carcinoma cell lines. Next, overexpression of microRNA-299-3p was found to inhibit oral squamous cell carcinoma cell proliferation and migration but promote apoptosis. In addition, forkhead box P4 was identified as a functional target of microRNA-299-3p. Our results provide a new perspective for the mechanisms underlying the progression of oral squamous cell carcinoma and a novel target for the treatment of oral squamous cell carcinoma.

Recently, circular RNAs (circRNAs) have been demonstrated as essential regulators in human cancers. However, the function and mechanism of circRNAs in breast cancer (BC) remain largely unknown and require to be investigated. In the present study, we found that circMYO9B was highly expressed in BC tissues by bioinformatics analysis. And we showed that circMYO9B expression was positively correlated with patients' prognosis. Moreover, we found that circMYO9B knockdown significantly suppressed the proliferation, migration and invasion of BC cells in vitro. In vivo assays also indicated that circMYO9B silence delayed tumor growth. In mechanism, we found that circMYO9B promoted the expression of FOXP4 by sponging miR-4316 in BC cells. We showed that the expression of miR-4316 was inversely associated with that of circMYO9B or FOXP4 in BC tissues. Finally, we found that restoration of FOXP4 expression significantly reversed the effects of circMYO9B knockdown on BC cell proliferation, migration and invasion. In conclusion, our findings demonstrated a key role of circMYO9B/miR-4316/FOXP4 axis in regulating BC progression., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Family of forkhead box transcription factors, including forkhead box P4 (FOXP4), plays an important role in oncogenesis. The current study is to evaluate the role of FOXP4 in regulating human non-small cell lung cancer (NSCLC). Quantitative RT-PCR and Western blot were performed to evaluate the gene and protein expressions of FOXP4 in six NSCLC cell lines and 55 NSCLC patients. Lentivirus of small hairpin RNA (FOXP4-shRNA) was used to downregulate FOXP4 in NSCLC cell lines A549 and H1703 cells. Its effect on NSCLC growth, invasion, and cell cycle were evaluated by cell proliferation assay, migration assay, and cell cycle assay, respectively. Dual luciferase assay and Western blot were used to examine whether microRNA-138 (miR-138) was an upstream regulator of FOXP4. The dependence of FOXP4 on miR-138 associated signaling pathway was evaluated by ectopically overexpressing enhancer of zeste homolog 2 (EZH2), a known miR-138 target in NSCLC. FOXP4 was highly expressed in both NSCLC cell lines and NSCLC patients. FOXP4 downregulation by FOXP4-shRNA markedly reduced cancer cell growth and invasion, as well as induced cell cycle arrest in A549 and H1703 cells. MiR-138 was confirmed to be an upstream regulator of FOXP4 and directly regulated FOXP4 expression in A549 and H1703 cells. FOXP4 downregulation-mediated inhibition on cancer cell growth and invasion was independent on overexpressing EZH2, another direct target of miR-138 in NSCLC. Our data demonstrated that FOXP4 was a critical regulator in NSCLC and independently associated with miR-138 regulation.

MicroRNAs (miRNAs) are a class of small, non-coding RNAs, which have demonstrated to important gene regulators, and have critical roles in diverse biological processes including cancer cell proliferation. Previous studies suggested microRNA-338-3p (miR-338-3p) was down-regulated and play tumor suppressor roles in gastric cancer, colorectal carcinoma and lung cancer. However, the role of miR-338-3p in hepatocellular carcinoma (HCC) is still unclear. In this study, we analyzed the expression of miR-338-3p in HCC tissues and HCC cell lines. We find that miR-338-3p was downregulated in HCC tissues and cell lines. Then functional studies demonstrate ectopic miR-338-3p expression significantly suppressed the in vitro proliferation and colony formation of HCC cells and cause to cell cycle arrest. Using bio-informatic method and report assay we identified a novel miR-338-3p target, FOXP4 in HCC cells. Furthermore, knockdown of FOXP4 have the similar effects in HCC corrected with miR-338-3p. These findings suggest that miR-338-3p regulates survival of HCC cells partially through the downregulation of FOXP4. Therefore, targeting with the miR-338-3p/FOXP4 axis might serve as a novel therapeutic application to treat HCC patients.