Recent studies found that forkhead box protein O1 (FoxO1) does not only demonstrate important biological functions in cell proliferation, gluconeogenesis, energy metabolism, and oxidative stress, but it also plays a vital role in the remodeling process of bones. FoxO1 can regulate bone mass by affecting osteoblasts, osteoclasts, and precursor cells. In this article, we review the role of FoxO1 in bone metabolism and elucidate its underlying mechanism.
Bone and Bones ; metabolism ; Cell Proliferation ; Forkhead Box Protein O1 ; Humans ; Osteoblasts ; Osteoclasts

Silent information regulator factor 2-related enzyme 1 (Sirtuins 1, SIRT1) is a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase, which can deacetylate histone and non-histone proteins and other transcription factors, and is involved in the regulation of many physiological functions, including gene transcription, energy metabolism, cell senescence and oxidative stress. Recent studies show that through adjusting the activity of endothelial nitric oxide syntheses (eNOS), p53, forkhead box class O (FOXO) and nuclear factor kappa B (NF-kappaB), SIRT1 can protect the functions of vascular endothelia and nerves in a variety of pathological conditions. Therefore, SIRT1 may be used as a potential therapeutic target of these diseases, particularly erectile dysfunction, which are associated with endothelial dysfunction.
Endothelium, Vascular ; physiology ; Erectile Dysfunction ; Forkhead Box Protein O1 ; Forkhead Transcription Factors ; metabolism ; Humans ; Male ; NAD ; metabolism ; NF-kappa B ; metabolism ; Nitric Oxide Synthase Type III ; metabolism ; Oxidative Stress ; Sirtuin 1 ; physiology ; Tumor Suppressor Protein p53 ; metabolism

OBJECTIVETo explore the expression of miR-135b in endometrial carcinoma and the mechanism by which miR-135b promotes the proliferation of endometrial cancer cells.

METHODSThe expressions of miR-135b and FOXO1 were using RT-PCR detected in 22 fresh endometrial cancer tissues and paired adjacent tissues and also in endometrial cancer cell lines JEC, Ishikawa, HEC-1-B, and RL-952. The RL-952 and Ishikawa cell lines were transfected with miR-135b mimics or inhibitors, and the changes in their proliferative activity were detected with MTT assay; the expressions of FOXO1 mRNA and protein were detected by RT-PCR and Western blotting, respectively.

RESULTSThe expression of miRNA135b was significantly up-regulated and FOXO1 expression was down-regulated in endometrial carcinoma tissues as compared with the adjacent tissues (P<0.05). The mRNA expression of miR-135b was negatively correlated with the expression of FOXO1 in endometrial carcinoma. In RL-952 and Ishikawa cell lines, transfection with miR-135b mimics obviously promoted the cell proliferation (P<0.05). Up-regulation of miR-135b significantly decreased the expressions of FOXO1 protein and mRNA (P<0.05), and down- regulation of miR-135b increased FOXO1 expressions (P<0.05).

CONCLUSIONSMiR-135b plays an important role in the occurrence and development of endometrial carcinoma partially by regulating its target gene FOXO1.

Cell Line, Tumor ; Cell Proliferation ; Down-Regulation ; Endometrial Neoplasms ; genetics ; metabolism ; Female ; Forkhead Box Protein O1 ; Forkhead Transcription Factors ; genetics ; metabolism ; Gene Expression Regulation, Neoplastic ; Humans ; MicroRNAs ; genetics ; metabolism ; RNA, Messenger ; Transfection ; Up-Regulation

OBJECTIVETo investigate the effect of Metformin on the proliferation and collagen synthesis of the human keloids fibroblasts as well as the effect on phosphorylation of Akt/FoxO1 signal transduction pathway.

METHODSFibroblasts of keloid were divided into control group treated with medium solution and experimental groups treated with different concentrations of Metformin. 48 h later CCK-8 assay was adopted to evaluate cell survival; Western blot was performed to detect the Akt and FoxO1 phosphorylation; and Hydroxyproline reagent kit was used to detect the collagen synthesis.

RESULTSWith different concentrations (30, 60, 90, 120 mmol/L) of Metformin, the absorbance of cultured keloid fibroblasts detected by CCK8 assay decreased by (13.30 ± 2.04)%, (22.64 ± 4.70)%, (54.00 ± 5.34)% and (63.12 ± 3.48)%. The growth of fibroblasts was suppressed by Metformin in a dose-dependent manner. It showed that the level of phoshpo-akt and phoshpo-foxOl in keloids fibroblasts in experimental groups was lower than that in the control group and the collagen synthesis were also decreased in experimental groups, all in a dose-dependent manner (P < 0.05, P < 0.01).

CONCLUSIONSMetformin can effectively inhibit the proliferation and collagen synthesis of the human keloids fibroblasts in vitro, which may be associated with the suppression of phosphorylation of Akt/FoxO1 signaling pathway

Cell Proliferation ; drug effects ; Collagen ; biosynthesis ; Dose-Response Relationship, Drug ; Fibroblasts ; cytology ; drug effects ; metabolism ; Forkhead Box Protein O1 ; Forkhead Transcription Factors ; metabolism ; Humans ; Keloid ; pathology ; Metformin ; pharmacology ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Signal Transduction ; drug effects

OBJECTIVE: In this study, the combined effect of two stressors, namely, electromagnetic fields (EMFs) from mobile phones and fructose consumption, on hypothalamic and hepatic master metabolic regulators of the AMPK/SIRT1-UCP2/FOXO1 pathway were elucidated to delineate the underlying molecular mechanisms of insulin resistance. METHODS: Weaned Wistar rats (28 days old) were divided into 4 groups: Normal, Exposure Only (ExpO), Fructose Only (FruO), and Exposure and Fructose (EF). Each group was provided standard laboratory chow ad libitum for 8 weeks . Additionally, the control groups, namely, the Normal and FruO groups, had unrestricted access to drinking water and fructose solution (15%), respectively. Furthermore, the respective treatment groups, namely, the ExpO and EF groups, received EMF exposure (1,760 MHz, 2 h/day x 8 weeks). In early adulthood, mitochondrial function, insulin receptor signaling, and oxidative stress signals in hypothalamic and hepatic tissues were assessed using western blotting and biochemical analysis. RESULT: In the hypothalamic tissue of EF, SIRT1, FOXO 1, p-PI3K, p-AKT, Complex III, UCP2, MnSOD, and catalase expressions and OXPHOS and GSH activities were significantly decreased ( P < 0.05) compared to the Normal, ExpO, and FruO groups. In hepatic tissue of EF, the p-AMPKα, SIRT1, FOXO1, IRS1, p-PI3K, Complex I, II, III, IV, V, UCP2, and MnSOD expressions and the activity of OXPHOS, SOD, catalase, and GSH were significantly reduced compared to the Normal group ( P < 0.05). CONCLUSION The findings suggest that the combination of EMF exposure and fructose consumption during childhood and adolescence in Wistar rats disrupts the closely interlinked and multi-regulated crosstalk of insulin receptor signals, mitochondrial OXPHOS, and the antioxidant defense system in the hypothalamus and liver.
Humans ; Rats ; Animals ; Adult ; Rats, Wistar ; Fructose/metabolism* ; Catalase ; Receptor, Insulin/metabolism* ; AMP-Activated Protein Kinases/metabolism* ; Electromagnetic Fields/adverse effects* ; Sirtuin 1/metabolism* ; Cell Phone ; Phosphatidylinositol 3-Kinases/metabolism* ; Forkhead Box Protein O1/metabolism* ; Uncoupling Protein 2

Physalin B (PB), one of the major active steroidal constituents of Solanaceae Physalis plants, has a wide variety of biological activities. We found that PB significantly down-regulated β-amyloid (Aβ) secretion in N2a/APPsw cells. However, the underlying mechanisms are not well understood. In the current study, we investigated the changes in key enzymes involved in β-amyloid precursor protein (APP) metabolism and other APP metabolites by treating N2a/APPsw cells with PB at different concentrations. The results indicated that PB reduced Aβ secretion, which was caused by down-regulation of β-secretase (BACE1) expression, as indicated at both the protein and mRNA levels. Further research revealed that PB regulated BACE1 expression by inducing the activation of forkhead box O1 (FoxO1) and inhibiting the phosphorylation of signal transducer and activator of transcription 3 (STAT3). In addition, the effect of PB on BACE1 expression and Aβ secretion was reversed by treatment with FoxO1 siRNA and STAT3 antagonist S3I-201. In conclusion, these data demonstrated that PB can effectively down-regulate the expression of BACE1 to reduce Aβsecretion by activating the expression of FoxO1 and inhibiting the phosphorylation of STAT3.
Alzheimer Disease ; Amyloid Precursor Protein Secretases/metabolism* ; Amyloid beta-Peptides/metabolism* ; Aspartic Acid Endopeptidases/metabolism* ; Down-Regulation ; Forkhead Box Protein O1/genetics* ; Humans ; Phosphorylation ; STAT3 Transcription Factor/metabolism* ; Secosteroids

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.
Animals ; Mice ; Brain Neoplasms/genetics* ; Cell Line, Tumor ; Cell Proliferation ; Drug Resistance, Neoplasm ; Feedback ; Gene Expression Regulation, Neoplastic ; Glioblastoma/metabolism* ; MicroRNAs/metabolism* ; Temozolomide/therapeutic use* ; Humans ; Forkhead Box Protein O1/metabolism*

Aging-related oxidative stress and free radical theory has become accepted increasingly as explaination, at least in part of the aging process. In murine models of aging, a genetic deficiency of the p66(Shc) (66-kilodalton isoform of Shc gene products) gene, which encodes a phosphotyrosine signal adapter protein, extends life span by 30%, and confers resistance to oxidative stress. Upon oxidative stress, p66(Shc) is phosphorylated at Ser36, contributing to inactivation of the forkhead-type transcription factors (FKHR/ FoxO1), which regulates the gene expression of cellular antioxidants. The p66(Shc) has a direct connection with the life span related signaling, which is conserved evolutionarily. Shc is basically not expressed in mature neurons of the adult brain and spinal cord. Instead, two Shc homologues, Sck/ShcB and N-Shc/ ShcC, which have been proved to be effective on oxidative stress and aging, are expressed in neural system. The expression of Shc-related genes is affected in the aging process, which may be relevant to cellular dysfunction, stress response and/or cognitive decline during aging.
Aging ; physiology ; Animals ; Brain ; metabolism ; Forkhead Box Protein O1 ; Forkhead Transcription Factors ; metabolism ; Gene Deletion ; Humans ; Mice ; Neurons ; metabolism ; Oxidative Stress ; physiology ; Phosphorylation ; Shc Signaling Adaptor Proteins ; deficiency ; genetics ; metabolism ; physiology ; Signal Transduction ; physiology ; Spinal Cord ; metabolism ; Src Homology 2 Domain-Containing, Transforming Protein 1 ; Src Homology 2 Domain-Containing, Transforming Protein 2 ; Src Homology 2 Domain-Containing, Transforming Protein 3

This study was aimed to analyze the expression profiles of PI3K/AKT signaling pathway genes from bone marrow samples of AML and ALL patients and normal samples. AML, ALL and normal bone marrow samples were collected from 6 AML, 6 ALL patients and 4 normal persons. The expression of PI3K/AKT signaling pathway genes including PTEN, CCND1, mTOR, RICTOR, FOXO1 were detected by real-time fluorescent quantification RT-PCR while GAPDH gene expression was used as an internal reference. The relative gene expression level was calculated by the method of the 2(-ΔΔCt). The results showed that the gene expression profiles were different between normal and leukemic groups. PTEN, mTOR and RICTOR expression levels were down-regulated, while FOXO1 and CCND1 levels were up-regulated in AML and ALL. PTEN was down-regulated in 10 out of the 12 samples; mTOR was down-regulated in 9 out of the 12 samples; RICTOR was down-regulated in 7 out of the 12 samples; FOXO1 was up-regulated in 9 out of the 12 samples and CCND1 was up-regulated in 7 out of the 12 samples. It is concluded that PI3K/AKT signal pathway is activated in both AML and ALL leukemic cells.
Carrier Proteins ; genetics ; metabolism ; Case-Control Studies ; Cyclin D1 ; genetics ; metabolism ; Forkhead Box Protein O1 ; Forkhead Transcription Factors ; genetics ; metabolism ; Gene Expression Regulation, Leukemic ; Humans ; Leukemia ; genetics ; metabolism ; PTEN Phosphohydrolase ; genetics ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; RNA, Messenger ; genetics ; Rapamycin-Insensitive Companion of mTOR Protein ; Signal Transduction ; TOR Serine-Threonine Kinases ; genetics ; metabolism ; Transcriptome

BACKGROUNDPancreatic β cells are susceptible to fatty acid-induced apoptosis. The 17β-estradiol (E2) protects pancreatic β cells from apoptosis, mediated by the estrogen receptor-α (ERα). The mRNA level and promoter activity of leukemia-related protein (LRP) 16 were significantly increased by E2 in ER-α and LRP16 was a co-activator of ER-α. The aim of the study was to assess the effects of LRP16 on fatty acid-induced apoptosis in MIN6 cells.

METHODSCells with over-expressing LRP16 were obtained by lipidosome transfection. Insulin content and glucose-stimulated insulin secretion (GSIS) were examined by radioimmunoassay. Western blotting was applied to detect protein expression. Apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and flow cytometry. The forkhead boxO1 (FoxO1) subcellular localization was determined by immunocytochemical analysis.

RESULTSMIN6-LRP16 cells with overexpression of LRP16 were successfully established, and protein expression of LRP16 was 2.29-fold of that of control cells (MIN6-3.1, P < 0.05). Insulin content and GSIS in MIN6-LRP16 were substantially increased compared with those in control cells. When cells were stimulated with glucose, increased phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and serine-threonine kinase (Akt) were observed in MIN6-LRP16. When cells were under palmitate pressure, the TUNEL-positive rate in MIN6-LRP16 was (17.0 ± 0.5)%, while it in MIN6-3.1 was (22.0 ± 0.4)%. In palmitate-treated cells, attenuated Akt phosphorylation was observed, but the attenuation in Akt activity was partially restored in MIN6-LRP16 cells. Meanwhile, nuclear localization of FoxO1 in MIN6-LRP16 was apparently reduced compared with that in control cells.

CONCLUSIONSLRP16 regulated insulin content and GSIS in MIN6 cells by ERK1/2 and Akt activated way. Meanwhile, LRP16 overexpression protected MIN6 cells from fatty acid-induced apoptosis by partially restoring Akt phosphorylation and inhibiting FoxO1 nuclear redistribution. Therefore, LRP16 played important roles not only in insulin content and GSIS but also in the antilipotoxic effect mediated by Akt/FoxO1 signaling.

Animals ; Apoptosis ; drug effects ; Blotting, Western ; Cell Line, Tumor ; Fatty Acids ; pharmacology ; Forkhead Box Protein O1 ; Forkhead Transcription Factors ; genetics ; metabolism ; Mice ; Neoplasm Proteins ; genetics ; metabolism ; Phosphorylation ; drug effects ; Proto-Oncogene Proteins c-akt ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; drug effects ; genetics