OBJECTIVE: To investigate the drug resistant related FOXO3/Bcl-6 signaling pathway in K562/G cell line and its related microRNA(miRNA) mechanisms. METHODS: The drug resistance potency of imatinib on K562/G was detected by MTT assay. The expression of FOXO3 and Bcl-6 proteins in K562 and K562/G cells was detected by Western blot. Real-time PCR (RT-PCR) was used to detect the expression of FOXO3 and Bcl-6 mRNA. The miRNA expression profiling in K562 and K562/G cells was analyzed by microarray technique, and the miRNA targeted to FOXO/Bcl-6 signaling pathway was identified. RESULTS: The expression of FOXO3 and Bcl-6 protein was significantly increased in K562/G cells as compared with that in K562 cells (P<0.01), the expression level of Bcl-6 mRNA showed no increase in K562/G cells. However, FOXO3 mRNA was up-regulated in K562/G cells (P<0.05). MiRNA microarray results showed that 109 miRNAs were expressed differentially in K562 and K562/G cells. The expression of 81 miRNAs were up-regulated while 28 miRNAs were down-regulated. Through reverse prediction by bioinformatics, miR-6718-5p, miR-5195-5p, miR-4711-3p, miR-4763-5p, miR-4664-5p and miR-3176 were related to FOXO/Bcl-6 signaling pathway. CONCLUSION The FOXO3/Bcl-6 signaling pathway contributes to imatinib resistance in K562/G cell line, and the miRNA expression profiles showed significant differences between K562/G and K562 cells.
Forkhead Box Protein O3/genetics* ; Humans ; Imatinib Mesylate/pharmacology* ; K562 Cells ; MicroRNAs/genetics* ; RNA, Messenger ; Signal Transduction

OBJECTIVETo explore the effects of EGFR-TKI AG1478 on the expression of FoxMl and FOXO3a genes in non-small cell cancer (NSCLC) cell lines, and explore the effect on cell proliferation and drug sensitivity to AG1478 after down-regulation of FOXMl and FOXO3a expression by RNAi technique.

METHODSHuman lung cancer cells were treated with AG1478 at different concentrations. RT-PCR and Western blot were used to examine the expression of P-EGFR, FOXM1, FOXO3a mRNA and protein. After transient transfection of FOXM1 and FOXO3a siRNA, RT-PCR and Western blot were employed to determine the transfection efficiency and expression of the related proteins. CCK-8 assay, colony formation assay and flow cytometry were performed to evaluate the cell proliferation, colony formation ability and the changes in cell cycle distribution.

RESULTSThe expressions of FOXM1 mRNA and protein were inhibited by AG1478 in a dose-dependent manner (both P < 0.05). After transfection with FOXM1 siRNA, the expressions of FOXM1 mRNA and protein, and proteins of cyclin B1, c-Myc, and Bcl-2 were significantly down-regulated, and the expressions of p21 and cleaved-PARP proteins were significantly up-regulated (all P < 0.05). The colony number of FOXM1siRNA transfection group was 37.3 ± 8.6, significantly lower than that of the blank control (135.3 ± 7.0) and negative control group (125.3 ± 7.5, P < 0.05). The colony formation inhibition rate was (7.40 ± 0.94)% in the negative control group and (72.4 ± 6.09)% in the FOXM1 siRNA transfection group. FOXM1siRNA transfection induced cell cycle arrest at G2/M phase with a percentage of (55.6 ± 4.83)%, significantly higher than that of the blank control [(24.30 ± 1.95)%] and negative control group [(21.3 ± 2.06)%, P < 0.05]. Additionally, the FOXM1siRNA transfection significantly increased the chemosensitivity of A549 cells to AG1478 (P < 0.05). Besides, AG1478 induced expression and nuclear relocation of FOXO3a. After the FOXO3a siRNA transfection, the expression of FOXM1 protein was significantly up-regulated, and resulted in a reduction of AG1478-induced inhibition of FOXM1.

CONCLUSIONSThe expression of FOXM1 is down-regulated by AG1478 via FOXO3a in the NSCLC cell lines, and then increases the chemosensitivity of A549 cells to AG1478. It suggests that FOXM1 could be a potential target for the therapy and drug exploitation for NSCLC.

Adenocarcinoma ; metabolism ; pathology ; Apoptosis ; Cell Cycle ; Cell Line, Tumor ; Cell Proliferation ; Dose-Response Relationship, Drug ; Down-Regulation ; Forkhead Box Protein M1 ; Forkhead Box Protein O3 ; Forkhead Transcription Factors ; genetics ; metabolism ; Humans ; Lung Neoplasms ; metabolism ; pathology ; Quinazolines ; administration & dosage ; pharmacology ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; genetics ; Receptor, Epidermal Growth Factor ; antagonists & inhibitors ; Transfection ; Tyrphostins ; administration & dosage ; pharmacology

The FOXO3a and FOXM1 forkhead transcription factors are key players in cancer initiation, progression, and drug resistance. Recent research shows that FOXM1 is a direct transcriptional target of FOXO3a, a vital downstream effector of the PI3K-AKT-FOXO signaling cascade. In addition, FOXM1 and FOXO3a also antagonize each other's activity by competitively binding to the same target genes, which are involved in chemotherapeutic drug sensitivity and resistance. Understanding the role and regulation of the FOXO-FOXM1 axis will provide insight into chemotherapeutic drug action and resistance in patients, and help to identify novel therapeutic approaches as well as diagnostic and predictive biomarkers.
Antineoplastic Agents ; pharmacology ; therapeutic use ; Carcinogenesis ; genetics ; metabolism ; Drug Resistance, Neoplasm ; Forkhead Box Protein M1 ; Forkhead Box Protein O3 ; Forkhead Transcription Factors ; genetics ; metabolism ; Humans ; Neoplasms ; drug therapy ; metabolism ; pathology ; Phosphatidylinositol 3-Kinases ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Signal Transduction

Transforming growth factor-β (TGF-β) exerts apoptotic effects on various types of malignant cells, including liver cancer cells. However, the precise mechanisms by which TGF-β induces apoptosis remain poorly known. In the present study, we have showed that threonine 32 (Thr32) residue of FoxO3 is critical for TGF-β to induce apoptosis via Bim in hepatocarcinoma Hep3B cells. Our data demonstrated that TGF-β induced FoxO3 activation through specific de-phosphorylation at Thr32. TGF-β-activated FoxO3 cooperated with Smad2/3 to mediate Bim up-regulation and apoptosis. FoxO3 (de)phosphorylation at Thr32 was regulated by casein kinase I-ε (CKI-ε). CKI inhibition by small molecule D4476 could abrogate TGF-β-induced FoxO/Smad activation, reverse Bim up-regulation, and block the sequential apoptosis. More importantly, the deregulated levels of CKI-ε and p32FoxO3 were found in human malignant liver tissues. Taken together, our findings suggest that there might be a CKI-FoxO/Smad-Bim engine in which Thr32 of FoxO3 is pivotal for TGF-β-induced apoptosis, making it a potential therapeutic target for liver cancer treatment.
Apoptosis ; genetics ; Apoptosis Regulatory Proteins ; biosynthesis ; Bcl-2-Like Protein 11 ; Carcinoma, Hepatocellular ; genetics ; pathology ; Cell Line, Tumor ; Forkhead Box Protein O3 ; Forkhead Transcription Factors ; genetics ; Gene Expression Regulation, Neoplastic ; Humans ; Liver Neoplasms ; genetics ; pathology ; Membrane Proteins ; biosynthesis ; Proto-Oncogene Proteins ; biosynthesis ; Threonine ; genetics ; Transforming Growth Factor beta ; genetics

This study investigated the effects of miRNA-155 on malignant biological characteristics of NK/T-cell lymphoma cell lines and the possible mechanism. The expression of miRNA-155 was detected in lymphoma cell lines from different sources (SNK-6, YTS, Jurkat and DOHH2) by real-time PCR. Lentiviral vectors (pLL3.7) that could overexpress or downexpress miRNA-155 were constructed. Recombinant lentiviral particles were prepared and purified, and their titers determined. The expression of miRNA-155 in the infected SNK-6 cells and the cell proliferation were detected by PCR and CCK-8, respectively. Flow cytometry was used to determine the apoptosis of infected SNK-6 cells. The target of miRNA155 was predicted from Targetscan website. The effect of miRNA155 on FOXO3a expression was examined by Western blotting. The results showed that among the human NK/T-cell lymphoma cell lines SNK-6, YTS, Jurkat and DOHH2, the expression of miRNA-155 was highest in SNK-6. The infection efficiency of the recombinant lentivirus in SNK-6 was more than 70% at multiplicity of infection (MOI) of 100. The expression of miRNA-155 was significantly increased in SNK-6 cells infected by lentivirus vectors with high expression of miRNA-155 (4 times higher than the control group), and profoundly decreased in those infected with lentiviruses with low expression of miRNA-155. The proliferation of letivirus-infected SNK-6 cells was decreased as the expression of miRNA-155 reduced. The apoptosis rate was increased with the reduction in the expression of miRNA-155. FOXO3a was found to be a possible target of miRNA155, as suggested by Targetscan website. Western blotting showed that the expression of FOXO3a was significantly elevated in SNK-6 cells with miRNA-155 inhibition. It was concluded that reduction in miRNA-155 expression can inhibit the proliferation of SNK-6 lymphoma cells and promote their apoptosis, which may be associated with regulation of FOXO3a gene.
Apoptosis ; genetics ; Forkhead Box Protein O3 ; Forkhead Transcription Factors ; genetics ; metabolism ; Gene Expression Regulation, Neoplastic ; Humans ; Jurkat Cells ; Lymphoma, T-Cell ; genetics ; metabolism ; pathology ; MicroRNAs ; biosynthesis ; genetics ; Natural Killer T-Cells ; metabolism ; pathology ; Neoplasm Proteins ; genetics ; metabolism ; RNA, Neoplasm ; biosynthesis ; genetics ; Transduction, Genetic

OBJECTIVETo observe the effect of Sam68 gene silencing on proliferation of nasopharyngeal carcinoma (NPC) cell line 5-8F and explore its possible molecular mechanism.

METHODSThe NPC cell line 5-8F was transfected with a small interfering RNA (siRNA) targeting Sam68 and the cell proliferation changes were observed. Quantitative RT-PCR and Western blotting were used to examine the changes in the expressions of Sam68, cell cycle-related proteins, and some up-stream proteins in the transfected cells.

RESULTSTransfection of 5-8F cells with Sam68-specific siRNA significantly lowered the mRNA and proteins levels of Sam68, suppressed cell proliferation, decreased the expression of Cyclin D1, and increased the expression of p27. The transfected cells showed obviously decreased expressions of p-FOXO3a, p-Akt and p-GSK-3β, but the expressions of FOXO3a, Akt and GSK-3β were not obviously affected.

CONCLUSIONSSam68 modulates the proliferation of NPC cells probably by activating Akt/FOXO3a pathway and regulating the cell proliferation-related molecules.

Adaptor Proteins, Signal Transducing ; genetics ; metabolism ; Carcinoma ; Cell Line, Tumor ; Cell Proliferation ; DNA-Binding Proteins ; genetics ; metabolism ; Forkhead Box Protein O3 ; Forkhead Transcription Factors ; metabolism ; Gene Silencing ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; Humans ; Nasopharyngeal Neoplasms ; genetics ; pathology ; Proto-Oncogene Proteins c-akt ; metabolism ; RNA, Messenger ; genetics ; metabolism ; RNA, Small Interfering ; genetics ; RNA-Binding Proteins ; genetics ; metabolism

OBJECTIVETo evaluate the effect of Foxo3a gene over-expression on the development of rat ovarian granulosa cells and in prevention of cisplatin-induced ovarian damage in rats.

METHODSRat ovarian granulose cells released mechanically from the ovaries were cultured in vitro and identified with HE staining and immunohistochemical staining for FSHR. A recombinant adenovirus carrying Foxo3a gene was constructed for infecting the granulose cells, and the cell growth and expressions of cyclin D1, p27, Bax, and Bim were detected; the cell apoptosis and cell cycle changes were detected using Hoechst/PI 33342 staining and flow cytometry, respectively. The transfected cells were challenged with cisplatin and the cell apoptosis was detected with flow cytometry.

RESULTSOver 90% of the cultured cells survived and contained more than 95% ovarian granulose cells. Infection of the cells with the recombinant adenovirus resulted in over-expressions of Foxo3a at the mRNA and protein levels at 36 h and 48 h after the infection, respectively. The infected cells showed suppressed proliferation, increased apoptotic rate and cell cycle arrest in G1 phase with increased expressions of Bim, p27, and cyclin D1 but without significant changes in Bax expression. Cisplatin exposure caused a significantly higher apoptosis rate in the infected cells than in the control cells.

CONCLUSIONOver-expression of Foxo3a gene can promote granulose cell apoptosis by increasing Bim expression and cause cell cycle arrest in G1 phase by increasing cyclin D1 and p27 expressions, but can not prevent the toxic effects of cisplatin on ovarian granulosa cells.

Animals ; Apoptosis ; Apoptosis Regulatory Proteins ; metabolism ; Bcl-2-Like Protein 11 ; Cell Cycle Checkpoints ; Cell Proliferation ; Cells, Cultured ; Cisplatin ; adverse effects ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Female ; Forkhead Box Protein O3 ; Forkhead Transcription Factors ; genetics ; metabolism ; Gene Expression ; Granulosa Cells ; cytology ; drug effects ; Membrane Proteins ; metabolism ; Proto-Oncogene Proteins ; metabolism ; Rats ; Transfection ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo investigate whether the ERK/FoxO3a signal axis could induce the inhibitory effect of vitexin 1 (VB-1) in HepG2 cell proliferation.

METHODThe MTT method was adopted to observe the effect of different concentrations of VB-1 on human hepatoma carcinoma cell line HepG2 and immortalized human embryo liver cell line L-02. The cell growth was assessed by the clone formation assay. The protein phosphorylation levels of ERK1/2 and FoxO3a were measured by the western blot.

RESULTVB-1 inhibited the viability of HepG2 cell line in a concentration-dependent manner, with a weak effect on L-02 cell line. VB-1 could effectively inhibit the anchorage-dependent growth of HepG2 cells, and reduce the expression levels of pERK1/2 and pFoxO3a in a concentration-dependent manner. MEK1/2 inhibitor PD98059 could enhance VB-1' s effect in inhibiting HepG2 cell proliferation and ERK1/2, FoxO3a phosphorylation.

CONCLUSIONVB-1 inhibits the proliferative activity of hepatoma carcinoma cell line HepG2 by blocking the ERK/FoxO3a signal axis.

Apigenin ; pharmacology ; Carcinoma, Hepatocellular ; drug therapy ; genetics ; metabolism ; physiopathology ; Cell Proliferation ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Extracellular Signal-Regulated MAP Kinases ; genetics ; metabolism ; Forkhead Box Protein O3 ; Forkhead Transcription Factors ; genetics ; metabolism ; Growth Inhibitors ; pharmacology ; Hep G2 Cells ; Humans ; Liver Neoplasms ; drug therapy ; genetics ; metabolism ; physiopathology ; Signal Transduction ; drug effects

OBJECTIVETo investigate the protective effect of ginsenoside Rg1 on oxygen-glucose deprivation (OGD) in PC-12 cells, and preliminarily discuss the potential molecular mechanism of mTOR/Akt/FoxO3 signaling pathway.

METHODThe OGD PC-12 cell model was established. The cell viability was measured by MTT assay. After the pretreatment with Rg1 with the concentration of 10, 20, 40 micromol x L(-1) for 24 h, the cell viability was observed. Lactate dehydrogenase (LDH) release, superoxide dismutase (SOD) ac- tivity and malondialdehyde (MDA) level were detected by colorimetry assay. mTOR, p-Akt(ser473), p-Akt(tjr308), Akt, p-FoxO3, FoxO3 in cytoplasm and nucleus, and total FoxO3 protein expression were detected by Western blot assay.

RESULTOGD could significantly in- hibit cell proliferation in 4-24 h in a time-dependent manner. After pretreatment for 24 h, Rg1 (20, 40 micromol x L(-1)) could notably elevate the cell viability and SOD viability and reduce the LDH release and MDA content. Besides, Rg1 also inhibited OGD-induced mTOR and p-Akt(ser473) decreases. After treatment for 6 h, OGD could reduce FoxO3 phosphorylation and promote FoxO3 in cytoplasm. This data suggested that Rg1 could protect PC-12 cell injury through mTOR/p-Akt/FoxO3 signaling pathway.

CONCLUSIONGinsenoside Rg1 could attenuate OGD-induced PC-12 cell injury. Its action mechanism may be closely related to activation of mTOR/p-Akt/FoxO3 signaling pathway.

Animals ; Apoptosis ; drug effects ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Forkhead Box Protein O3 ; Forkhead Transcription Factors ; genetics ; metabolism ; Ginsenosides ; pharmacology ; Glucose ; metabolism ; Oxygen ; metabolism ; PC12 Cells ; Protective Agents ; pharmacology ; Proto-Oncogene Proteins c-akt ; genetics ; metabolism ; Rats ; Signal Transduction ; drug effects ; TOR Serine-Threonine Kinases ; genetics ; metabolism

OBJECTIVETo explore the role and mechanisms of FOXO3a nuclear translocation in neuronal apoptosis after hypoxia-ischemia (HI).

METHODSOne hundred and sixty 10-day-old Sprague-Dawly rats were randomly divided into two groups: HI and sham-operated. The right common carotid artery was ligated followed by hypoxia exposure for 2.5 hours in the HI group. The sham-operated group rats were not subjected to carotid artery ligation or hypoxia treatment. Rat cerebral cortex was collected at 0.5, 2, 4, 8 and 24 hours after hypoxia. Western blot was used to detect expression of total FOXO3a protein, pnuclear and cytoplasmic FOXO3a and Bim. TUNEL staining was used to detect apoptotic cells.

RESULTSThe nuclear protein of FOXO3a obviously increased from 0.5 to 24 hours after HI in a time-dependent manner compared with the sham-operated group (P<0.01). On the contrary, cytoplasmic protein evidently decreased from 0.5 to 24 hours in the HI group compared with the sham-operated group (P<0.01). Bim protein increased from 0.5 hour, peaked at 2 hours, started to decline at 4 hours (P<0.01), and returned to baseline level at 8 and 24 hours after HI in the HI group compared with the sham-operated group. TUNEL positive cells started to express at 4 hours, and peaked at 24 hours after HI (P<0.01). However, TUNEL positive cells were rarely found in the sham-operated group.

CONCLUSIONSHI induces FOXO3a translocation from cytoplasm to nucleus, and enhances protein expression of its target gene Bim in the neonatal rat brain. The upregulation of Bim expression might be related to neuronal apoptosis.

Animals ; Animals, Newborn ; Apoptosis ; Apoptosis Regulatory Proteins ; analysis ; Bcl-2-Like Protein 11 ; Female ; Forkhead Box Protein O3 ; Forkhead Transcription Factors ; genetics ; physiology ; Hypoxia-Ischemia, Brain ; pathology ; Male ; Membrane Proteins ; analysis ; Neurons ; pathology ; Proto-Oncogene Proteins ; analysis ; Rats ; Rats, Sprague-Dawley