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.

BACKGROUND AND OBJECTIVES: MicroRNAs are small non-coding RNAs involved in pathogenesis and progression of human malignancies. MicroRNA-491-5p (miR-491-5p) is down-regulated in many human cancers where it would serve as a tumour suppressor. However, the role played by miR-491-5p in pathogenesis of human osteosarcoma has remained largely unknown. This study has been conducted to examine effects of miR-491-5p on migration and proliferation of cells of the SAOS-2 and MG63 osteosarcoma lines, and mechanisms of those effects.
MATERIALS AND METHODS: Levels of miR-491-5p expression in osteosarcoma tissues and in human osteosarcoma cell lines were studied using qualitative real-time polymerase chain reaction (qRT-PCR) methods. Cell viability was detected using the CCK-8 and EdU assays, while the transwell assay was used to evaluate migration and invasion. Apoptosis was analysed uing flow cytometry and the Hoechst 33342 nuclear staining method. A dual-luciferase reporter system was used to confirm the target gene of miR-491-5p. The electrophoretic mobility shift assay (EMSA) with DIG-labelled double-stranded FOXP4 oligonucleotides was used to confirm whether or not miR-491-5p suppressed FOXP4 activation.
RESULTS: Cells of osteosarcoma tissues and cell lines had low levels of miR-491-5p expression, but high levels of forkhead-box P4 (FOXP4) expression. Transfection of SAOS-2 and MG63 cells with miR-491-5p mimics inhibited expression of FOXP4 protein, which suppressed cell growth and migration, but induced apoptosis. Dual-luciferase reporter assays confirmed FOXP4 as the target gene for miR-491-5p. Overexpression of miR-491-5p suppressed FOXP4 activity in SAOS-2 and MG63 cells. Knockdown of FOXP4 in SAOS-2 and MG63 cells using an RNAi strategy resulted in reduced levels of cell proliferation and migration, but increased levels of apoptosis.
CONCLUSION: Our in vitro studies showed that up-regulation of miR-491-5p suppressed proliferation of the human osteosarcoma cells and induced apoptosis by targeting FOXP4. These findings suggest that miR-491-5p could be further studied as a potential clinical diagnostic or predictive biomarker for human osteosarcoma.

The long non-coding RNA MFI2 antisense RNA is overexpressed in human cancer tissues and its increased expression is associated with occurrence and metastasis of cancer. However, the underlying mechanism in evolution and progression of human osteosarcoma is not well known. In the present study, we aimed to evaluate the molecular mechanism of lncRNA MFI2 in promoting osteosarcoma cell proliferation and suppressing apoptosis. We found that the lncRNA MFI2 was significantly overexpressed in human osteosarcoma tissues. Knockdown of lncRNA MFI2 expression suppressed MG63 and SAOS-2 cell proliferation, migration and invasion, and induced cell apoptosis. Furthermore, the expression of forkhead box P4 (FOXP4) was significantly increased and it was positively associated with lncRNA MFI2 expression in tumor tissues. In addition, knockdown of FOXP4 expression by RNA interference strategy inhibited osteosarcoma cell proliferation, migration and invasion, and promoted cell apoptosis. All the results indicated lncRNA MFI2 could promote proliferation and migration of osteosarcoma cells by regulating FOXP4 expression, which suggested critical roles of lncRNA MFI2 and FOXP4 in occurrence and development of human osteosarcoma.

In the past twenty-five years, over 700 case-control association studies on the risk of prostate cancer have been published worldwide, but their results were largely inconsistent. To facilitate following and explaining these findings, we performed a systematic meta-analysis using allelic contrasts for gene-specific SNVs from at least three independent population-based case-control studies, which were published in the field of prostate cancer between August 1, 1990 and August 1, 2015. Across 66 meta-analyses, a total of 20 genetic variants involving 584,100 subjects in 19 different genes (KLK3, IGFBP3, ESR1, SOD2, CAT, CYP1B1, VDR, RFX6, HNF1B, SRD5A2, FGFR4, LEP, HOXB13, FAS, FOXP4, SLC22A3, LMTK2, EHBP1 and MSMB) exhibited significant association with prostate cancer. The average summary OR was 1.33 (ranging from: 1.016-3.788) for risk alleles and 0.838 (ranging from: 0.757-0.896) for protective alleles. Of these positive variants, FOXP4 rs1983891, LMTK2 rs6465657 and RFX6 rs339331 had not been previously meta-analyzed. Further analyses with sufficient power design and investigations of the potential biological roles of these genetic variants in prostate cancer should be conducted.

BACKGROUND: The tumor suppressor forkhead box P4 (FOXP4) plays important roles in oncogenesis, and the FOXP4 variant rs1983891 is associated with prostate cancer (PCa) in several studies. However, association studies conducted in Northern and Southern Chinese have provided conflicting results. Therefore, here we performed fine mapping of FOXP4 to identify the association with PCa and the potential application in Chinese men.
METHODS: We examined 11 variants spaced approximately 55 kb apart spanning FOXP4 using high-resolution melting-curve analysis and sequencing methods in 286 PCa patients and 630 controls, and the association between these variants and PCa risk was evaluated. Additionally, we evaluated the cumulative effect of rs4714476 and 2 variants in 8q24 (rs16901966, rs10090154) confirmed in our previous study.
RESULTS: Of 11 SNPs, only rs4714476-C at the 5' near gene of FOXP4 was associated with increased age-adjusted PCa risk (p = 0.012, OR = 1.32, 95% CI = 1.06 - 1.63) and aggressive PCa (p = 0.026). The CG haplotype covering rs4714476-C demonstrated significant differences between PCa cases and controls (p = 0.009). The cumulative effect analysis showed men who carried any combination of 1, 2, or 3 risk genotypes had a gradually increased PCa risk (age-adjusted OR is from 1.244 to 3.312).
CONCLUSIONS: These data suggest that rs4714476 at the 5' near gene of FOXP4 potentially contributes to the susceptibility of PCa in Chinese men. The cumulative effect of rs4714476 at FOXP4 and 8q24 could increase PCa risk.

PURPOSE: Prostate cancer (PCa) is one of the most common malignancies in males, and multiple genetic studies have confirmed association with susceptibility to PCa. However, the risk conferred in men living in China is unkown. We selected 6 previously identified variants as candidates to define their association with PCa in Chinese men.
METHODS: We genotyped 6 single nucleotide polymorphisms (SNPs) (rs1465618, rs1983891, rs339331, rs16901966, rs1447295 and rs10090154) using high resolution melting (HRM) analysis and assessed their association with PCa risk in a case-control study of 481 patients and 480 controls in a Chinese population. In addition, the individual and cumulative contribution for the risk of PCa and clinical covariates were analysed.
RESULTS: We found that 5 of the 6 genetic variants were associated with PCa risk. The T allele of rs339331 and the G allele of rs16901966 showed a significant association with PCa susceptibility: OR (95%CI)= 0.78 (0.64-0.94), p<0.009 and OR (95%CI)= 0.66 (0.54-0.81), p<0.0001, as well as A allele of rs1447295 (OR [95%CI]=1.46 (1.17-1.84), p<0.001) and T allele of rs10090154 (OR [95%CI]= 0.58 (0.46-0.74), p<0.0001). rs339331(T) was associated with a 0.71-fold and 1.42-fold increase of PCa risk by dominant model (p=0.007) and recessive model (p=0.007). rs16901966 (G) was associated with a 0.51-fold and 1.98-fold increase of PCa risk by dominant model (p=0.006) and recessive model (p=0.0058). rs10090154 (T) was associated with a 1.89-fold and 0.53-fold increase of PCa risk by dominant model (p=0.000006) and recessive model (p=0.000006). And, rs1983891(C) was associated with a 0.77-fold increase of PCa risk by recessive model (p=0.045). rs1447295 was associated with a 1.57-fold increase of PCa risk by dominant model (p=0.008). rs1465618 showed no significant association with PCa. The cumulative effects test of risk alleles (rs rs1983891, rs339331, rs16901966, rs1447295 and rs10090154) showed an increasing risk to PCa in a frequency-dependent manner (ptrend=0.001), and men with more than 3 risk alleles had the most significant susceptibility to PCa (OR=1.99, p=0.001), compared with those who had one risk allele (OR=1.17, p=0.486).
CONCLUSION: Our results provide further support for association of the THADA, FOXP4, GPRC6A/RFX6 and 8q24 genes with Pca in Asian populations. Further work is still required to determine the functional variations and finally clarify the underlying biological mechanisms.

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.

BACKGROUND: KLK3 gene products, like human prostate-specific antigen (PSA), are important biomarkers in the clinical diagnosis of prostate cancer (PCa). G protein-coupled receptor RFX6, C2orf43 and FOXP4 signaling plays important roles in the development of PCa. However, associations of these genes with PCa in northern Chinese men remain to be detailed. This study aimed to investigate their impact on occurrence and level of malignancy.
METHODS: All subjects were from Beijing and Tianjin, including 266 cases with prostate cancer and 288 normal individuals as controls. We evaluated associations between clinical covariates (age at diagnosis, prostate specific antigen, Gleason score, tumor stage and aggressive) and 6 candidate PCa risk loci, genotyped by PCR- high resolution melting curve and sequencing methods.
RESULTS: Case-control analysis of allelic frequency of PCa associated with PCa showed that one of the 6 candidate risk loci, rs339331 in the RFX6 gene, was associated with reduced risk of prostate cancer (odds ratio (OR) = 0.73, 95% confidence interval (CI) =0.57-0.94, P = 0.013) in northern Chinese men. In addition, subjects with CX (CC+TC) genotypes had a decreased risk for prostrate cancer compared to those carrying the TT homozygote (OR =0.64, 95% CI = 0.45- 0.90, P = 0.008). The TT genotype of 13q22 (rs9600079, T) was associated with tumor stage (P=0.044, OR=2.34, 95% CI=0.94-5.87). Other SNPs were not significantly associated with clinical covariates in prostate cancer (P > 0.05). CONCLUSIONS. rs339331 in the RFX6 gene may be associated with prostate cancer as a susceptibility locus in northern Chinese men.

BACKGROUND: Prostate cancer represents the leading cause of male death across the world. A recent genome-wide association study (GWAS) identified five novel susceptibility loci for prostate cancer in the Japanese population. This study is to replicate and fine map the potential association of these five loci with prostate cancer in the Chinese Han population.
METHODS: In Phase I of the study, we tested the five single nucleotide polymorphisms (SNPs) which showed the strongest association evidence in the original GWAS in Japanese. The study sample consists of 1,169 Chinese Hans, comprising 483 patients and 686 healthy controls. Then in phase II, flanking SNPs of the successfully replicated SNPs in Phase I were genotyped and tested for association with prostate cancer to fine map those significant association signals.
RESULTS: We successfully replicated the association of rs13385191 (located in the C2orf43 gene, P = 8.60×10(-5)), rs12653946 (P = 1.33×10(-6)), rs1983891 (FOXP4, P = 6.22×10(-5)), and rs339331 (GPRC6A/RFX6, P = 1.42×10(-5)) with prostate cancer. The most significant odds ratio (OR) was recorded as 1.41 (95% confidence interval 1.18-1.68) for rs12653946. Rs9600079 did not show significant association (P = 8.07×10(-2)) with prostate cancer in this study. The Phase II study refined these association signals, and identified several SNPs showing more significant association with prostate cancer than the very SNPs tested in Phase I.
CONCLUSIONS: Our results provide further support for association of the C2orf43, FOXP4, GPRC6A and RFX6 genes with prostate cancer in Eastern Asian populations. This study also characterized the novel loci reported in the original GWAS with more details. Further work is still required to determine the functional variations and finally clarify the underlying biological mechanisms.

Prostate cancer is one of the most common malignancies in males throughout the world, and its incidence is increasing in Asian countries. We carried out a genome-wide association study and replication study using 4,584 Japanese men with prostate cancer and 8,801 control subjects. From the thirty-one associated SNPs reported in previous genome-wide association studies in European populations, we confirmed the association of nine SNPs at P < 1.0 x 10(-7) and ten SNPs at P < 0.05 in the Japanese population. The remaining 12 SNPs showed no association (P > 0.05). In addition, we report here five new loci for prostate cancer susceptibility, at 5p15 (lambda-corrected probability P(GC) = 3.9 x 10(-18)), GPRC6A/RFX6 (P(GC) = 1.6 x 10(-12)), 13q22 (P(GC) = 2.8 x 10(-9)), C2orf43 (P(GC) = 7.5 x 10(-8)) and FOXP4 (P(GC) = 7.6 x 10(-8)). These findings advance our understanding of the genetic basis of prostate carcinogenesis and also highlight the genetic heterogeneity of prostate cancer susceptibility among different ethnic populations.

FOXP2 mutation causes a severe inherited speech and language defect, while the related transcription factors FOXP1, FOXP3 and FOXP4 are implicated in cancer. FOXP2 mRNA and protein expression were characterised in normal human tissues, haematological cell lines and multiple myeloma (MM) patients' samples. FOXP2 mRNA and protein were absent in mononuclear cells from different anatomical sites, lineages and stages of differentiation. However, FOXP2 mRNA and protein was detected in several lymphoma (8/20) and all MM-derived cell lines (n = 4). FOXP2 mRNA was expressed in bone marrow samples from 96% of MM patients (24/25), 66.7% of patients with the pre-neoplastic plasma cell proliferation monoclonal gammopathy of undetermined significance (MGUS) (6/9), but not in reactive plasma cells. The frequency of FOXP2 protein expression in CD138(+) plasma cells was significantly higher in MGUS (P = 0.0005; mean 46.4%) and MM patients (P < or = 0.0001; mean 57.3%) than in reactive marrows (mean 2.5%). FOXP2 (>10% nuclear positivity) was detectable in 90.2% of MM (55/61) and 90.9% of MGUS (10/11) patients, showing more frequent expression than CD56 and labelling 75% of CD56-negative MM (9/12). FOXP2 represents the first transcription factor whose expression consistently differentiates normal and abnormal plasma cells and FOXP2 target genes are implicated in MM pathogenesis.

Chromosome translocations in the common epithelial cancers are abundant, yet little is known about them. They have been thought to be almost all unbalanced and therefore dismissed as mostly mediating tumour suppressor loss. We present a comprehensive analysis by array painting of the chromosome translocations of breast cancer cell lines HCC1806, HCC1187 and ZR-75-30. In array painting, chromosomes are isolated by flow cytometry, amplified and hybridized to DNA microarrays. A total of 200 breakpoints were identified and all were mapped to 1 Mb resolution on bacterial artificial chromosome (BAC) arrays, then 40 selected breakpoints, including all balanced breakpoints, were further mapped on tiling-path BAC arrays or to around 2 kb resolution using oligonucleotide arrays. Many more of the translocations were balanced at 1 Mb resolution than expected, either reciprocal (eight in total) or balanced for at least one participating chromosome (19 paired breakpoints). Second, many of the breakpoints were at genes that are plausible targets of oncogenic translocation, including balanced breaks at CTCF, EP300/p300 and FOXP4. Two gene fusions were demonstrated, TAX1BP1-AHCY and RIF1-PKD1L1. Our results support the idea that chromosome rearrangements may play an important role in common epithelial cancers such as breast cancer.

Gene expression profiling studies have reported up-regulated mRNA expression of the FOXP1 forkhead transcription factor in response to normal B-cell activation and high expression in a poor prognosis subtype of diffuse large B-cell lymphoma (DLBCL). The purpose of this study was to investigate the prognostic importance of FOXP1 protein expression in an independent series of DLBCL.First, the specificity of our FOXP1 monoclonal antibody was verified by confirming that it did not recognize the closely related FOXP2, FOXP3, or FOXP4 proteins. FOXP1 protein expression was then analyzed by immunohistochemistry using a DLBCL tissue microarray constructed from 101 previously untreated de novo cases from the British Columbia Cancer Agency. FOXP1 expression was scored as either positive (>30% positive nuclei) or negative (<30% positive nuclei). The overall survival curves clearly showed that patients grouped as FOXP1-positive (40%) had a significantly decreased overall survival (P = 0.0001). FOXP1-positive patients had a median overall survival of 1.6 years compared with 12.2 years in FOXP1-negative cases. In addition, FOXP1-positive patients showed a clear trend to earlier progression in comparison to the FOXP1-negative patients. The analysis of FOXP1 expression within low, medium, and high International Prognostic Index groupings found that FOXP1-negative patients had better overall survival within each group indicating that FOXP1 expression has predictive value independent of the International Prognostic Index subgrouping, a finding that was confirmed in multivariate analysis. These initial results suggest that FOXP1 expression may be important in DLBCL pathogenesis.

Human Forkhead-box (FOX) gene family consists of at least 43 members, including FOXA1, FOXA2, FOXA3, FOXB1, FOXC1, FOXC2, FOXD1, FOXD2, FOXD3, FOXD4, FOXD5 (FOXD4L1), FOXD6 (FOXD4L3), FOXE1, FOXE2, FOXE3, FOXF1, FOXF2, FOXG1 (FOXG1B), FOXH1, FOXI1, FOXJ1, FOXJ2, FOXJ3, FOXK1, FOXK2, FOXL1, FOXL2, FOXM1, FOXN1, FOXN2 (HTLF), FOXN3 (CHES1), FOXN4, FOXN5 (FOXR1), FOXN6 (FOXR2), FOXO1 (FOXO1A), FOXO2 (FOXO6), FOXO3 (FOXO3A), FOXO4 (MLLT7), FOXP1, FOXP2, FOXP3, FOXP4, and FOXQ1. FOXE3-FOXD2 (1p33), FOXQ1-FOXF2-FOXC1 (6p25.3), and FOXF1-FOXC2-FOXL1 (16q24.1) loci are FOX gene clusters within the human genome. Members of FOX subfamilies A-G, I-L and Q were grouped into class 1 FOX proteins, while members of FOX subfamilies H and M-P were grouped into class 2 FOX proteins. C-terminal basic region within the FOX domain was the common feature of class 1 FOX proteins. FOXH1 and FOXO1 mRNAs are expressed in human embryonic stem (ES) cells. FOXC1, FOXC2, FOXE1, FOXE3, FOXL2, FOXN1, FOXP2 and FOXP3 genes are mutated in human congenital disorders. FOXA1 gene is amplified and over-expressed in esophageal and lung cancer. FOXM1 gene is up-regulated in pancreatic cancer and basal cell carcinoma due to the transcriptional regulation by Sonic Hedgehog (SHH) pathway. FOXO1 gene is fused to PAX3 or PAX7 genes in rhabdomyosarcoma. FOXO3 and FOXO4 genes are fused to MLL gene in hematological malignancies. Deregulation of FOX family genes leads to congenital disorders, diabetes mellitus, or carcinogenesis. Expression profiles, genetic alterations and epigenetic changes of FOX family genes as well as binding proteins and target genes of FOX family transcription factors should be comprehensively investigated to develop novel therapeutics and preventives for human diseases.

Forkhead proteins have been demonstrated to play key roles in embryonic development, cell cycle regulation, and oncogenesis. We report the characterization of a new forkhead transcription factor, which is a member of the FoxP subfamily. In adult tissues FoxP4 is expressed in heart, brain, lung, liver, kidney, and testis. By Northern hybridization, very low levels of FoxP4 expression were found as early as E7 during embryonic development. Embryonic expression was highest at E11 and subsequently decreased at E15 and E17. In situ hybridization revealed expression of FoxP4 in the developing lung and gut, suggesting a role for FoxP4 during the development of these organs. In addition, FoxP4 was found to be significantly reduced in patients with kidney tumors. Lastly, FoxP4 matches an uncharacterized human EST that has previously been shown to be down-regulated in larynx carcinoma.