FOXO1-miR-506 axis promotes chemosensitivity to temozolomide and suppresses invasiveness in glioblastoma through a feedback loop of FOXO1/miR-506/ETS1/FOXO1 / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

To explore the role of forkhead box protein O1 (FOXO1) in the progression of glioblastoma multiforme (GBM) and related drug resistance, we deciphered the roles of FOXO1 and miR-506 in proliferation, apoptosis, migration, invasion, autophagy, and temozolomide (TMZ) sensitivity in the U251 cell line using in vitro and in vivo experiments. Cell viability was tested by a cell counting kit-8 (CCK8) kit; migration and invasion were checked by the scratching assay; apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining and flow cytometry. The construction of plasmids and dual-luciferase reporter experiment were carried out to find the interaction site between FOXO1 and miR-506. Immunohistochemistry was done to check the protein level in tumors after the in vivo experiment. We found that the FOXO1-miR-506 axis suppresses GBM cell invasion and migration and promotes GBM chemosensitivity to TMZ, which was mediated by autophagy. FOXO1 upregulates miR-506 by binding to its promoter to enhance transcriptional activation. MiR-506 could downregulate E26 transformation-specific 1 (ETS1) expression by targeting its 3'-untranslated region (UTR). Interestingly, ETS1 promoted FOXO1 translocation from the nucleus to the cytosol and further suppressed the FOXO1-miR-506 axis in GBM cells. Consistently, both miR-506 inhibition and ETS1 overexpression could rescue FOXO1 overactivation-mediated TMZ chemosensitivity in mouse models. Our study demonstrated a negative feedback loop of FOXO1/miR-506/ETS1/FOXO1 in GBM in regulating invasiveness and chemosensitivity. Thus, the above axis might be a promising therapeutic target for GBM.

Value of serum miR-922 and miR-506 expression levels in the diagnosis and prognostic assessment of childhood acute lymphoblastic leukemia / 中国当代儿科杂志

OBJECTIVES@#To study the value of serum miR-922 and miR-506 expression levels in the diagnosis and prognostic assessment of childhood acute lymphoblastic leukemia (ALL).@*METHODS@#A total of 132 children with ALL (ALL group) and 80 healthy children (healthy control group) were prospectively selected in this study. Quantitative real-time polymerase chain reaction was used to measure the expression levels of serum miR-922 and miR-506 in both groups. Receiver operating characteristic (ROC) curves were plotted to analyze the diagnostic value of miR-922 and miR-506 for childhood ALL. The Kaplan-Meier method was used to plot survival curves, and multivariate COX regression models were used to analyze the risk factors for poor prognosis in children with ALL.@*RESULTS@#The ALL group had significantly higher expression levels of serum miR-922 and miR-506 than the control group (@*CONCLUSIONS@#The expression levels of miR-922 and miR-506 are of good value in the diagnosis and prognostic assessment of childhood ALL.

MiR-506-3p suppresses the proliferation of ovarian cancer cells by negatively regulating the expression of MTMR6

MicroRNAs have been reported to play a crucial role in ovarian cancer (OC) as the most lethal malignancy of the women.Here, we found miR-506-3p was significantly down-regulated in OC tissues compared with corresponding adjacent nontumor tissues. Ectopic miR-506-3p expression inhibited OC cell growth and proliferation using MTT and colony formationassay. Additionally, flow cytometry analysis showed that the overexpression of miR-506-3p induced cell cycle G0/G1phase arrest and cell apoptosis in OC cells. A luciferase reporter assay confirmed that the myotubularin-related protein 6(MTMR6) was the target of miR-506-3p. The expression of MTMR6 was increased in OC tissues compared with adjacenttissues using immunohistochemistry. Elevated MTMR6 protein levels were confirmed in OC cells lines compared withimmortalized fallopian tube epithelial cell line FTE187 using western blotting. In addition, knockdown of MTMR6 imitatedthe effects of miR-506-3p on cell proliferation, cell cycle progression and apoptosis in OC cells. Furthermore, rescueexperiments using MTMR6 overexpression further verified that MTMR6 was a functional target of miR-506-3p. Our dataindicate that miR-506-3p might serve as a tumor suppressor gene and propose a new regulatory mechanism of MTMR6 bymiR-506-3p in OC.

lncRNA FOXD2-AS1 regulates proliferation and apoptosis of cervical cancer cells via targeting miR-506-5p / 中国肿瘤生物治疗杂志

@#Objective: To investigate whether long non-coding RNA (lncRNA) FOXD2-AS1 targets miR-506-5p to regulate proliferation and apoptosis of cervical cancer cells. Methods: Human normal cervical cells Ect1/E6E7 and cervical cancer cell lines (HeLa, Siha and Caski) were cultured in vitro, and the expression levels of FOXD2-AS1 and miR-506-5p in cells were detected by qPCR. The cervical cancer cells with FOXD2-AS1 knockdown and miR-506-5p over-expression were constructed by liposome transfection technology, and the proliferation and apoptosis of cells were detected by MTT assay and flow cytometry respectively, the expression of proliferation-related proteins CyclinD1, p21, p27 and apoptosis-related proteins Bcl-2, BAX, cleaved-capase-3 were detected by WB. Dual luciferase reporter assay was used to verify whether FOXD2-AS1 would target miR-506-5p; and the effects of simultaneous inhibition of FOXD2-AS1 and miR-506-5p on proliferation and apoptosis of cervical cancer cells were also analyzed. Results: Compared with Ect1/E6E7 cells, the expression of FOXD2-AS1 significantly increased while the expression of miR-506-5p significantly decreased in cervical cancer HeLa, Siha and Caski cells (all P<0.01). FOXD2-AS1 knockdown significantly inhibited the protein expressions of CyclinD1, Bcl-2 and cell proliferationin cervical cancer cells, but promoted the protein expressions of p21, p27, BAX, cleavedcapase-3, and cell apoptosis (all P<0.01). miR-506-5p over-expression significantly inhibited the protein expressions of CyclinD1, Bcl2 and cell proliferation in cervical cancer cells, but promoted the protein expressions of p21, BAX, and cell apoptosis (all P<0.01). Dual luciferase reporter gene assay confirmed that FOXD2-AS1 negatively regulated the expression of miR-506-5p in cervical cancer cells (P<0.01). Inhibition of miR-506-5p expression reversed the effect of FOXD2-AS1 knockdown on proliferation and apoptosis of cervical cancer cell (P<0.01). Conclusion: FOXD2-AS1 modulates proliferation and apoptosis of cervical cancer cells by negatively regulating the expression of miR-506-5p.

MiR-506 Promotes Natural Killer Cell Cytotoxicity against Human Hepatocellular Carcinoma Cells by Targeting STAT3

PURPOSE: It is well documented that natural killer (NK) cytotoxicity against hepatocellular carcinoma (HCC) cells is impaired in HCC, which might account for the failure of anti-tumor immune response. miRNAs are considered as important regulators for the development and functions of NK cells. However, the entire role of miR-506 in NK cells remains far from being addressed. MATERIALS AND METHODS: The expressions of miR-506 and signal transducer and activator of transcription 3 (STAT3) mRNA in primary NK cells from HCC patients and healthy controls were detected by quantitative real-time PCR. NK cell cytotoxicity was assessed by CFSE/7AAD cytotoxicity assay and lactate dehydrogenase assay. Luciferase reporter assay, RNA immunoprecipitation assay, and western blot were conducted to confirm the interaction between miR-506 and STAT3. RESULTS: miR-506 expression was downregulated and STAT3 mRNA was upregulated in primary NK cells from HCC patients. Primary NK cells from HCC patients showed remarkably reduced cytotoxicity against SMMC7721 or HepG2 cells. NK cell cytotoxicity was positively correlated with miR-506 expression and negatively correlated with STAT3 mRNA expression. Additionally, miR-506 overexpression enhanced NK cell cytotoxicity against HCC cells, while miR-506 inhibitor showed the reverse effect. Moreover, miR-506 could suppress STAT3 expression by directly targeting 3′-untranslated regions of STAT3. A negative correlation between miR-506 and STAT3 mRNA expression in HCC patients was observed. Mechanistically, overexpressing STAT3 greatly reversed miR-506-mediated promotion of NK cell cytotoxicity against HCC cells. CONCLUSION: miR-506 enhanced NK cell cytotoxicity against HCC cells by targeting STAT3, suggesting that modulating miR-506 expression maybe a promising approach for enhancing NK cell-based antitumor therapies.

Effects of miR-506 on malignance phenotypes of hepatocellular carcinoma cells / 天津医药

Objective To investigate effects of microRNA-506 (miR-506) on malignant phenotypes of hepatocellular carcinoma (HCC) cells, including cellular viability, proliferation and invasion. Methods HCC cell lines HepG2 and QGY-7703 were served as model. Five experimental groups were established in this study, including cell control, pcDNA 3 blank vector control, miR-506 over-expression, pSIH1 blank vector control and miR-506 suppression groups. Real-time reverse transcription PCR assay was performed to measure miR-506 level. CCK-8, colony formation and Transwell assays were performed to detect viability, colony formation activity and invasion activity of HCC cell lines, respectively. Effects of miR-506 on these indexes were evaluated. Results In HepG2 and QGY-7703 cell lines, miR-506 level increased in the miR-506 over-expression group (P0.05). Conclusion miR-506 plays a tumor suppressor role in HCC cells by inhibiting cell viability, colony formation and invasion.

MicroRNA-506 inhibits malignancy of colorectal carcinoma cells by targeting LAMC1 / 实用医学杂志

Objective To investigate the effects of microRNA-506 (miR-506) on malignant phenotype of colorectal carcinoma cells. To identify the target gene of miR-506 in colon carcinoma. Methods SW480 cells were divided into five groups, known as normal cell group, miR-506 overexpression and, miR-506 inhibition groups with their vehicle groups.The migration and invasion abilities of SW480 cells were measured with Transwell migration assay. Cell viability and colony forming activities were measured by CCK8 and colony formation assays, respectively. Furthermore, bioinformatic method, green fluorescent protein (GFP) reporter assays, quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot were applied to predict potential target genes of miR-506. Results The number of migrated and invasive cells, viability and clonality in the miR-506 overexpression groups reduced. LAMC1 mRNA and protein levels in the miR-506 overexpression groups were lower than those in the control groups. Conclusion LAMC1 is a direct target gene for miR-506 and miR-506 could inhibit the cell migratioin and invasion.