Effects of lentiviral-mediated Foxp1 and Foxq1 RNAi on the hepatocarcinoma cell

Impact of FOXP1 rs2687201 genetic variant on the susceptibility to HCV-related hepatocellular carcinoma in Egyptians

Hepatocellular carcinoma (HCC) constitutes a challenging health problem in Egypt due to the high incidence of hepatitis C virus (HCV) infection. Improved understanding of genetic mechanisms underlying the individual predisposition to HCC will lead to enhancements in the early diagnosis, treatment, and prevention of this disease. Transcription factor forkhead box P1 (FOXP1) is involved in the cellular processes of proliferation, differentiation, metabolism, and longevity. In addition, it has been implicated in hepatic tumorigenesis. The present study explored the association of C/A single-nucleotide polymorphism in the FOXP1 gene (rs2687201) with HCC susceptibility in HCV Egyptian patients. The study included 108 patients with HCV-dependant HCC, 86 HCV patients, and 80- age and gender-matched healthy controls. rs2687201 genotyping was performed by allelic discrimination method using TaqMan real-time PCR assays while FOXP1 gene expression and protein level were determined using qRT-PCR and enzyme-linked immunoassay, respectively. Our results revealed a significant association between FOXP1 rs2687201 and HCC risk where (A) allele was significantly more frequent in patients with HCC compared to controls (odds ratio [OR]: 1.88, 95% confidence interval [CI]: 1.17-3.04, p = 0.01) and to HCV patients (OR: 1.85, 95% CI: 1.62-2.94, p = 0.012). Furthermore, FOXP1 gene and protein expression levels were remarkably higher in (CA + AA) than in CC genotype carriers in a dominant model. The (CA + AA) genotype displayed a significantly shorter overall survival than the CC genotype in HCC patients. In conclusion, FOXP1 gene polymorphism rs2687201 is significantly associated with HCC, but not with HCV infection, in Egyptian patients.

Retracted: Lentivirus-Mediated siRNA Targeting ER-α Inhibits Tumorigenesis and Induces Apoptosis in Hepatocarcinoma Cells

[This retracts the article DOI: 10.1155/2015/490681.].

The role of Foxq1 in proliferation of human dental pulp stem cell

This study aimed to investigate the role for Foxq1 in proliferation activity regulation of dental pulp stem cells (DPSCs). Proliferation of DPSC was induced by calcium hydroxide, then expression alteration of Foxq1 was evaluated. Lentivirus was employed to manipulate Foxq1 level in DPSC, and proliferation activities were evaluated. To look into mechanism regulating Foxq1 level after calcium hydroxide stimulation, expressions of various microRNAs were evaluated, then bioinformatics study and dual-luciferase study were carried out to confirm targeting relationship between microRNA and Foxq1. The result of our study indicated that proliferation activities of DPSCs were enhanced after calcium hydroxide stimulation, during which expression of Foxq1 was also up-regulated. Cell viability and progression from G1 to S phase were both improved with overexpression of Foxq1, and microRNAs profiling study and dual-luciferase result suggested miR-320b contributed to the up-regulation of Foxq1 after calcium hydroxide stimulation. These results suggested that miR-320b mediated Foxq1 up-regulation promote proliferation of dental pulp stem cells.

FOXP1 enhances tumor cell migration by repression of NFAT1 transcriptional activity in MDA-MB-231 cells

Until now, forkhead box P1 (FOXP1) has been identified as a tumor suppressor in several correlation studies in breast cancer. Although FOXP1 is defined as a transcriptional repressor that interacts with other transcription factors in various mechanistic studies, there is no study that explains its repressor functions in breast cancer biology. This study demonstrated the repressor function of FOXP1 on nuclear factor of activated T cells (NFAT1) and the migratory effect of this repression in MDA-MB-231 breast cancer cells. Co-immunoprecipitation experiments were performed for the investigation of protein-protein interaction between two transcription factors. Protein-protein interaction on DNA was investigated with EMSA and transcriptional effects of FOXP1 on NFAT1, luciferase reporter assay was performed. Wound healing assay was used to analyze the effects of overexpression of FOXP1 on tumor cell migration. This study showed that FOXP1 has protein-protein interaction with NFAT1 on DNA and enhances breast cancer cell migration by repressing NFAT1 transcriptional activity and FOXP1 shows oncogenic function by regulating breast cancer cell motility.

Downregulation of FOXP1 Inhibits Cell Proliferation in Hepatocellular Carcinoma by Inducing G1/S Phase Cell Cycle Arrest

Forkhead box P1 (FOXP1) belongs to a family of winged-helix transcription factors that are involved in the processes of cellular proliferation, differentiation, metabolism, and longevity. FOXP1 can affect cell proliferation and migratory ability in hepatocellular carcinoma (HCC) in vitro. However, little is known about the mechanism of FOXP1 in the proliferation of HCC cells. This study aimed to further explore the function of FOXP1 on the proliferation of HCC cells as well as the relevant mechanism involved. Western blot analysis, tumor xenograft models, and flow cytometry analysis were performed to elucidate the function of FOXP1 in the regulation of cell proliferation in human HCC. We observed that silencing FOXP1 significantly suppressed the growth ability of HCC cells both in vitro and in vivo. In addition, knockdown of FOXP1 induced G1/S phase arrest, and the expression of total and phosphorylated Rb (active type) as well as the levels of E2F1 were markedly decreased at 24 h; however, other proteins, including cyclin-dependent kinase (CDK) 4 and 6 and cyclin D1 did not show noticeable changes. In conclusion, downregulation of FOXP1 inhibits cell proliferation in hepatocellular carcinoma by inducing G1/S phase cell cycle arrest, and the decrease in phosphorylated Rb is the main contributor to this G1/S phase arrest.

FOXP1 forkhead transcription factor is associated with the pathogenesis of endometrial cancer

Endometrial cancers are mostly estrogen-dependent. FOXP1 is a P subfamily of forkhead box (FOX), and known as an estrogen-responsive transcription factor. The aims of this study were to examine histological location of FOXP1 in normal and malignant endometrium, and to investigate a possible association between FOXP1 and other factors considered to be involved in pathogenesis of endometrial cancer. The levels of FOXP1, estrogen receptor (ER)α, and ERβ expression were examined immunohistochemically in normal and malignant endometrium obtained from 75 women (8 normal, 8 atypical endometrial hyperplasia, and 59 endometrial cancers from grade 1 to 3). The effects of estrogen on ERα, FOXP1, KRAS, and PTEN expression were analyzed in telomerase-immortalized human endometrial stromal cells (T HESCs) by Western blotting. Western blotting was also used to examine the effect of FOXP1 plasmid DNA or siRNA transfection on KRAS and PTEN expression in Ishikawa cells (well differentiated endometrioid adenocarcinoma), HEC-50B cells (poorly differentiated endometrioid adenocarcinoma), and T HESCs, respectively. FOXP1 was expressed in normal and malignant endometrium, but the rate of expression was different depending upon menstrual cycle and pathological grade of malignancy. FOXP1 expression in nucleus and cytoplasm of grade 3 endometrioid cancers was significantly lower than that of grade 1 and 2 ones. Estradiol increased levels of FOXP1 and KRAS expression in a dose- and time-dependent manner in T HESCs cells, and FOXP1 transfection or knockdown led to increase or decrease of KRAS expression but not PTEN. KRAS expression level was significantly related to FOXP1 and ERα levels in cancer tissues. Estradiol did not affect KRAS expression in T HESCs cells transfected with FOXP1 siRNA. These results suggest that FOXP1 is involved in estrogen dependent endometrial cancers through KRAS pathway.

FOXQ1 is overexpressed in laryngeal carcinoma and affects cell growth, cell cycle progression and cell invasion

Forkhead box Q1 (FOXQ1) is a forkhead transcription factor that is involved in numerous biological processes and has been shown to participate in tumorigenesis. However, the clinical significance of the expression of this protein in laryngeal carcinoma, and the mechanisms underlying its regulation in this disease remain unclear. The aim of present study was to measure the expression of FOXQ1 in laryngeal carcinoma, and to examine its effect on tumorigenesis. In the present study, reverse transcription-quantitative polymerase chain reaction and western blotting were employed to measure FOXQ1 expression in laryngeal carcinoma tissue samples, small interfering RNA specific to FOXQ1, was transfected into Hep2 cells and its effect on cell proliferation, cell cycle progression and cell migration was examined, using a CCK-8 assay, flow cytometry and a transwell migration assay, respectively. The results showed overexpression of FOXQ1 mRNA and protein in laryngeal cancer tissue samples. Inhibition of FOXQ1 suppressed cell growth and invasion, and arrested cells in the G0/G1 phase. Overexpression of FOXQ1 is associated with the development of laryngeal carcinoma and may enhance tumorigenesis through its effects on cell proliferation, cell cycle progression and cell migration.

FOXP1 regulation via the PI3K/Akt/p70S6K signaling pathway in breast cancer cells

Loss of Forkhead box P1 (FOXP1) protein expression confers a poor prognosis in sporadic and familial breast cancer patients, and the FOXP1 gene maps to a tumor suppressor locus at chromosome 3p14. Although correlation studies have indicated that FOXP1 has a role in tumor suppression, determination of the regulatory mechanism of FOXP1 is required to establish its function in breast cancer. It has previously been identified that FOXP1 is regulated by estrogen in breast cancer and that treatment with bisphenol A is effective for regulating the transformation of the normal human breast epithelial cell line, MCF-10F. In addition, FOXO-regulated activation of FOXP1 inhibits the apoptosis of MCF-10F cells following tamoxifen and Akt inhibitor VIII administration. The present study indicates that FOXP1 regulation occurs via a PI3K/Akt/p70S6 kinase (p70S6K) signaling pathway. Following treatment with wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3K)/Akt, MCF7 and MDA-MB-231 breast cancer cells demonstrated decreased FOXP1 protein expression levels; this result was also observed in the small interfering (si)RNA silencing of Akt. By contrast, overexpression of Akt resulted in increased FOXP1 protein expression levels in the MDA-MB-231 cells compared with the control cell lysates. Furthermore, treatment with rapamycin, a specific inhibitor of the mammalian target of rapamycin/p70S6K cascade, resulted in decreased FOXP1 expression in the MCF7 cells, but not in the MDA-MB-231 cells, which were resistant to rapamycin-induced inhibition. In addition, silencing of p70S6K using siRNA produced a marked decrease in FOXP1 expression. These data indicate that FOXP1 protein expression is regulated by a PI3K/Akt/p70S6K signaling cascade in breast cancer.