FRAT1 promotes the angiogenic properties of human glioblastoma cells via VEGFA.

Glioblastoma is a common central nervous system tumor and despite considerable advancements in treatment patient prognosis remains poor. Angiogenesis is a significant prognostic factor in glioblastoma, anti­angiogenic treatments represent a promising therapeutic approach. Vascular endothelial growth factor A (VEGFA) is a predominant regulator of angiogenesis and mounting evidence suggests that the Wnt signaling pathway serves a significant role in tumor angiogenesis. As a positive regulator of the Wnt/ß­catenin signaling pathway, frequently rearranged in advanced T­cell lymphomas­1 (FRAT1) is highly expressed in human glioblastoma and is significantly associated with glioblastoma growth, invasion and migration, as well as poor patient prognosis. Bioinformatics analysis demonstrated that both VEGFA and FRAT1 were highly expressed in most tumor tissues and associated with prognosis. However, whether and how FRAT1 is involved in angiogenesis remains to be elucidated. In the present study, the relationship between FRAT1 and VEGFA in angiogenesis was investigated using the human glioblastoma U251 cell line. Small interfering RNAs (siRNAs) were used to silence FRAT1 expression in U251 cells, and the mRNA and protein expression levels of VEGFA, as well as the concentration of VEGFA in U251 cell supernatants, were determined using reverse transcription­quantitative PCR, western blotting and ELISA. A tube formation assay was conducted to assess angiogenesis. The results demonstrated that siRNA knockdown significantly decreased the protein expression levels of FRAT1 in U251 cells and markedly decreased the mRNA and protein expression levels of VEGFA. Furthermore, the concentration of VEGFA in the cell supernatant was significantly reduced and angiogenesis was suppressed. These results suggested that FRAT1 may promote VEGFA secretion and angiogenesis in human glioblastoma cells via the Wnt/ß­catenin signaling pathway, supporting the potential use of FRAT1 as a promising therapeutic target in human glioblastoma.

WNT signaling pathway regulator-FRAT2 affects oncogenesis and prognosis of basal-like breast cancer.

BACKGROUND: Breast cancer is the most common malignant cancer in women worldwide and is one of the leading causes of cancer death. Basal-like breast cancer (BLBC) is an aggressive subtype of breast cancer for which targeted therapy has poor efficacy. Therefore, research into the molecular pathogenesis of BLBC is urgent for developing effective targeted therapeutic treatments. METHODS: We collected relevant data from the Cancer Genome Atlas (TCGA), including transcriptome, copy number variation, and survival data. We also gathered 30 pairs clinical samples of cancer tissues and non-cancerous tissues to perform Western Blotting (WB) to reveal the encoded protein expression levels. Besides, we knocked down frequently rearranged in advanced T-cell lymphomas 2 (FRAT2) expression in two representative cell lines (T47D and MDA-MB-231 cells). The cell cycle progression was analyzed, while the apoptosis experiments were also conducted to explore the molecular pathogenesis of FRAT2 in BLBC. RESULTS: The aberrant activation of the WNT pathway and highly expressed FRAT2 were specifically identified across the BLBC genome comparing to other types of tumor. In addition, FRAT2 expression was found to be positively associated with its copy number variations (P=9.126×10-23). For further investigation, we found the expression level of FRAT2 was related to the poor overall survival of BLBC patients (P=0.049). The results of WB revealed that FRTA2-encoded protein was overexpressed in BLBC tissues. Based on results in T47D and MDA-MB-231 cells in vitro, we found that knocking down FRAT2 can inhibit the proliferation of these two cell lines. In cell cycle progression experiments, cell cycle arrested in the G2/M phase. Meanwhile, increased apoptosis was also found in the shFRAT2 cell group in vitro. CONCLUSIONS: In BLBC basal-like breast cancer, we can assume that FRAT2 is a potential treatment target.

STAT1 is a modulator of the expression of frequently rearranged in advanced T-cell lymphomas 1 expression in U251 cells.

Aberrant expression of frequently rearranged in advanced T-cell lymphomas 1 (FRAT1) contributes to poor prognosis in a number of carcinomas. However, its role in glioma remains controversial. In the present study, gene expression profiling was performed using Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO) functional enrichment and ingenuity pathway analysis (IPA) to evaluate the differential expression of genes and proteins in FRAT1 knockdown U251 glioma cells in comparison with the control. Western blot analysis was conducted to assess the expression levels of FRAT1 and STAT1. A total of 895 downregulated genes were identified in FRAT1-silenced U251 cells. The most enriched processes determined by GO and KEGG analysis of the 895 differentially expressed genes were associated with proliferation, migration and invasion. According to IPA, significant canonical pathways, including the interferon, hepatic fibrosis and Wnt/ß-catenin signaling pathways, were identified to be the major enriched pathways. The elevated expression of STAT1 in U251 cells was validated. These results highlighted the regulatory role of FRAT1 in glioma cells with upregulated STAT1 expression.

FRAT1 Enhances the Proliferation and Tumorigenesis of CD133+Nestin+ Glioma Stem Cells In Vitro and In Vivo.

Glioma stem cells (GSCs) are considered the source for development, recurrence, and poor prognosis of glioma, so treatment targeted GSCs is of great interest. The frequently rearranged in advanced T cell lymphomas-1 (FRAT1) gene is an important member of the Wnt/ß-catenin signaling transduction pathway, and aberrantly activation of Wnt signaling has been identified to contribute to the tumorigenesis, proliferation, invasion of a variety kinds of cancer stem cells. However, correlations between FRAT1 and GSCs and the specific mechanisms remain unclear. In this study, we aimed to investigate the effect of FRAT1 on GSCs proliferation, colony formation, sphere formation and tumorigenesity in vitro and in vivo and its underlying mechanism. Lentiviral transfection was used to construct GSCs with low FRAT1 expression. The expression of FRAT1 on GSCs proliferation in vitro was assessed by cell counting kit-8(CCK-8). Colony formation and sphere formation assays were conducted to assess the colony and sphere formation ability of GSCs. Then, an intracranial glioma nude mouse model was built to measure the effect of low FRAT1 expression on GSCs proliferation and tumorigenesity in vivo. Real-time PCR, Western blot, and Immunohistochemistry were processed to detect the mRNA and protein expressions of FRAT1, ß-catenin in the glioma tissue of xenograft mice to study their correlations. The functional assays verifed that low FRAT1 expression inhibited CD133+Nestin+ GSCs proliferation, colony formation, sphere formation ability in vitro. In vivo GSCs xenograft mice model showed that low FRAT1 expression suppressed the proliferation and tumorigenesity of CD133+Nestin+ GSCs and reduced ß-catenin mRNA and protein expression. Furthermore, the expression of FRAT1 and ß-catenin were positively correlated. Altogether, results indicate that FRAT1 enhances the proliferation, colony formation, sphere formation and tumorigenesity of CD133+Nestin+ glioma stem cells in vitro and in vivo as well as the expression of ß-catenin. Therefore, inhibiting proliferation of GSCs and FRAT1 may be a molecular target to GSCs in treating human glioma in the future.

Epigenetic silencing of miR-490-3p promotes development of an aggressive colorectal cancer phenotype through activation of the Wnt/ß-catenin signaling pathway.

The Wnt/ß-catenin pathway is known to contribute to colorectal cancer (CRC) progression, although little is known about the contribution of ß-catenin on this process. We investigated the role of miR-490-3p, which was recently reported to suppress tumorigenesis through its effect on Wnt/ß-catenin signaling. We found that hypermethylation of the miR-490-3p promoter down-regulates miR-490-3p expression in CRC tissue. Gain- and loss-of-function assays in vitro and in vivo reveal that miR-490-3p suppresses cancer cell proliferation by inducing apoptosis and inhibits cell invasiveness by repressing the initiation of epithelial-to-mesenchymal transition (EMT), a key mechanism in cancer cell invasiveness and metastasis. The frequently rearranged in advanced T-cell lymphomas (FRAT1) protein was identified as a direct target of miR-490-3p and contributes to its tumor-suppressing effects. miR-490-3p appears to have an inhibitory effect on ß-catenin expression in nuclear fractions of CRC cells, whereas FRAT1 expression is associated with the accumulation of ß-catenin in the nucleus of cells, which could be weakened by transfection with miR-490-3p. Our findings suggest that the miR-490-3p/FRAT1/ß-catenin axis is important in CRC progression and provides new insight into the molecular mechanisms underlying CRC. They may help to confirm the pathway driving CRC aggressiveness and serve for the development of a novel miRNA-targeting anticancer therapy.

Silencing of FRAT1 by siRNA inhibits the proliferation of SGC7901 human gastric adenocarcinoma cells.

Frequently rearranged in advanced T cell lymphomas-1 (FRAT1) positively regulates the Wnt/ß-catenin signaling pathway by inhibiting glycogen synthase kinase-3 mediated phosphorylation of ß-catenin. FRAT1 is a proto-oncogene, implicated in tumorigenesis. The present study aimed to investigate the effects of FRAT1 silencing on the proliferation and apoptosis of SGC7901 cells. FRAT1 in SGC7901 cells was silenced by RNA interference. Reverse transcription-quantitative polymerase chain reaction was used for the analysis of FRAT1 mRNA and western blotting was used to evaluate FRAT1 and ß-catenin protein levels. Cell proliferation was analyzed by the MTT assay. Cell cycle distribution and apoptosis were analyzed by flow cytometry. The expression of FRAT1 mRNA, FRAT1 and ß-catenin protein in FRAT1-silenced SGC7901 cells were reduced significantly compared to untreated cells. The proliferation of FRAT1 silenced SGC7901 cells decreased significantly The FRAT1 silenced SGC7901 cells were arrested at G0/G1 stage to a greater degree, and apoptosis was increased. In summary, silencing of FRAT1 inhibits SGC7901 cell proliferation and induces apoptosis, possible through a reduction in ß-catenin expression. FRAT1 may serve as a prognostic biomarker and therapeutic target for gastric cancer.

Classifying chemical mode of action using gene networks and machine learning: a case study with the herbicide linuron.

The herbicide linuron (LIN) is an endocrine disruptor with an anti-androgenic mode of action. The objectives of this study were to (1) improve knowledge of androgen and anti-androgen signaling in the teleostean ovary and to (2) assess the ability of gene networks and machine learning to classify LIN as an anti-androgen using transcriptomic data. Ovarian explants from vitellogenic fathead minnows (FHMs) were exposed to three concentrations of either 5α-dihydrotestosterone (DHT), flutamide (FLUT), or LIN for 12h. Ovaries exposed to DHT showed a significant increase in 17ß-estradiol (E2) production while FLUT and LIN had no effect on E2. To improve understanding of androgen receptor signaling in the ovary, a reciprocal gene expression network was constructed for DHT and FLUT using pathway analysis and these data suggested that steroid metabolism, translation, and DNA replication are processes regulated through AR signaling in the ovary. Sub-network enrichment analysis revealed that FLUT and LIN shared more regulated gene networks in common compared to DHT. Using transcriptomic datasets from different fish species, machine learning algorithms classified LIN successfully with other anti-androgens. This study advances knowledge regarding molecular signaling cascades in the ovary that are responsive to androgens and anti-androgens and provides proof of concept that gene network analysis and machine learning can classify priority chemicals using experimental transcriptomic data collected from different fish species.