Explore the vast range of titles available.

Circular RNAs are a class of non-coding RNAs that are receiving extensive attention. Despite reports showing circular RNAs acting as microRNA sponges, the biological functions of circular RNAs remain largely unknown. We show that in patient tumor samples and in a panel of cancer cells, circ-Foxo3 was minimally expressed. Interestingly, during cancer cell apoptosis, the expression of circ-Foxo3 was found to be significantly increased. We found that silencing endogenous circ-Foxo3 enhanced cell viability, whereas ectopic expression of circ-Foxo3 triggered stress-induced apoptosis and inhibited the growth of tumor xenografts. Also, expression of circ-Foxo3 increased Foxo3 protein levels but repressed p53 levels. By binding to both, circ-Foxo3 promoted MDM2-induced p53 ubiquitination and subsequent degradation, resulting in an overall decrease of p53. With low binding affinity to Foxo3 protein, circ-Foxo3 prevented MDM2 from inducing Foxo3 ubiquitination and degradation, resulting in increased levels of Foxo3 protein. As a result, cell apoptosis was induced by upregulation of the Foxo3 downstream target PUMA.

Purpose. To explore the effects of ulinastatin on the proliferation and apoptosis of breast cancer cells and the relevant mechanism of action. Methods. Breast cancer cells (MCF-7) were cultured and randomly divided into three groups, namely, control group, ulinastatin group, and ulinastatin+extracellular-regulated protein kinase (ERK) inhibitor group. Then, the Cell Counting Kit-8 (CCK-8) assay was carried out to detect the effect of ulinastatin on the viability of breast cancer cells. The effects of ulinastatin on the proliferation and apoptosis of breast cancer cells were determined via EdU staining and Hoechst 33258 staining assays, respectively. The messenger ribonucleic acid (mRNA) and protein expression levels of ERK and forkhead box O3 (FOXO3) in breast cancer cells were measured through reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. Results. In comparison with the control group, the ulinastatin group displayed decreased viability of breast cancer cells, a decreased positive rate of 5-ethynyl-2′-deoxyuridine (EdU) staining, an increased positive rate of Hoechst 33258 staining, and reduced mRNA and protein levels of ERK and FOXO3 in breast cancer cells. Compared with those in the ulinastatin group, the viability of breast cancer cells was lowered, the positive rate of EdU staining was reduced, the positive rate of Hoechst 33258 staining was raised, and the mRNA and protein levels of ERK and FOXO3 in breast cancer cells clearly declined in the ulinastatin+ERK inhibitor group. Conclusion. Ulinastatin inhibits the proliferation and promotes the apoptosis of breast cancer cells. The possible mechanism of action is associated with the suppression of the ERK signaling pathway.

The objective of this study was to examine FoxO expression and FoxO function in meniscus. In menisci from human knee joints with osteoarthritis (OA), FoxO1 and 3 expression were significantly reduced compared with normal menisci from young and old normal donors. The expression of FoxO1 and 3 was also significantly reduced in mouse menisci during aging and OA induced by surgical meniscus destabilization or mechanical overuse. Deletion of FoxO1 and combined FoxO1, 3, and 4 deletions induced abnormal postnatal meniscus development in mice and these mutant mice spontaneously displayed meniscus pathology at 6 mo. Mice with Col2Cre-mediated deletion of FoxO3 or FoxO4 had normal meniscus development but had more severe aging-related damage. In mature AcanCreERT2 mice, the deletion of FoxO1, 3, and 4 aggravated meniscus lesions in all experimental OA models. FoxO deletion suppressed autophagy and antioxidant defense genes and altered several meniscus-specific genes. Expression of these genes was modulated by adenoviral FoxO1 in cultured human meniscus cells. These results suggest that FoxO1 plays a key role in meniscus development and maturation, and both FoxO1 and 3 support homeostasis and protect against meniscus damage in response to mechanical overuse and during aging and OA.

Maintenance of a healthy proteome is essential for cellular homeostasis and loss of proteostasis is associated with tissue dysfunction and neurodegenerative disease. The mechanisms that support proteostasis in healthy cells and how they become defective during aging or in disease states are not fully understood. Here, we investigate the transcriptional programs that are essential for neural stem and progenitor cell (NSPC) function and uncover a program of autophagy genes under the control of the transcription factor FOXO3. Using genomic approaches, we observe that FOXO3 directly binds a network of target genes in adult NSPCs that are involved in autophagy, and find that FOXO3 functionally regulates induction of autophagy in these cells. Interestingly, in the absence of FOXO activity, aggregates accumulate in NSPCs, and this effect is reversed by TOR (target of rapamycin) inhibition. Surprisingly, enhancing FOXO3 causes nucleation of protein aggregates, but does not increase their degradation. The work presented here identifies a genomic network under the direct control of a key transcriptional regulator of aging that is critical for maintaining a healthy mammalian stem cell pool to support lifelong neurogenesis.

Intervertebral disk (IVD) degeneration is a prevalent age‐associated musculoskeletal disorder and a major cause of chronic low back pain. Aging is the main risk factor for the disease, but the molecular mechanisms regulating IVD homeostasis during aging are unknown. The aim of this study was to investigate the function of FOXO, a family of transcription factors linked to aging and longevity, in IVD aging and age‐related degeneration. Conditional deletion of all FOXO isoforms (FOXO1, 3, and 4) in IVD using the Col2a1Cre and AcanCreER mouse resulted in spontaneous development of IVD degeneration that was driven by severe cell loss in the nucleus pulposus (NP) and cartilaginous endplates (EP). Conditional deletion of individual FOXO in mature mice showed that FOXO1 and FOXO3 are the dominant isoforms and have redundant functions in promoting IVD homeostasis. Gene expression analyses indicated impaired autophagy and reduced antioxidant defenses in the NP of FOXO‐deficient IVD. In primary human NP cells, FOXO directly regulated autophagy and adaptation to hypoxia and promoted resistance to oxidative and inflammatory stress. Our findings demonstrate that FOXO are critical regulators of IVD homeostasis during aging and suggest that maintaining or restoring FOXO expression can be a therapeutic strategy to promote healthy IVD aging and delay the onset of IVD degeneration.

Rab escort protein 1 (REP1) is a component of Rab geranyl-geranyl transferase 2 complex. Mutations in REP1 cause a disease called choroideremia (CHM), which is an X-linked eye disease. Although it is postulated that REP1 has functions in cell survival or death of various tissues in addition to the eye, how REP1 functions in normal and cancer cells remains to be elucidated. Here, we demonstrated that REP1 is required for the survival of intestinal cells in addition to eyes or a variety of cells in zebrafish, and also has important roles in tumorigenesis. Notably, REP1 is highly expressed in colon cancer tissues and cell lines, and silencing of REP1 sensitizes colon cancer cells to serum starvation- and 5-FU-induced apoptosis. In an effort to elucidate the molecular mechanisms underlying REP1-mediated cell survival under those stress conditions, we identified FOXO3 as a binding partner of REP1 using a yeast two-hybrid (Y2H) assay system, and we demonstrated that REP1 blocked the nuclear trans-localization of FOXO3 through physically interacting with FOXO3, thereby suppressing FOXO3-mediated apoptosis. Importantly, the inhibition of REP1 combined with 5-FU treatment could lead to significant retarded tumor growth in a xenograft tumor model of human cancer cells. Thus, our results suggest that REP1 could be a new therapeutic target in combination treatment for colon cancer patients.

ObjectiveTo observe the effects of electroacupuncture (EA) on reproductive outcomes in women with Shen (Kidndy) deficiency syndrome after in vitro fertilization-embryo transfer (IVF-ET), and explore the underlying molecular mechanism.MethodsSixty-six infertile patients with Shen deficiency syndrome undergoing IVF-ET were divided into EA or control groups according to a random table, 33 cases in each group. Before undergoing IVF, patients in the EA and control groups received EA therapy and placebo needle puncture, respectively, for 3 menstrual cycles. Shen deficiency syndrome scores were assessed. Other outcome measures included the number of retrieved oocytes and fertilization, high-quality embryo and clinical pregnancy rates. Follicular fluid was collected on the day of oocyte retrieval, and granulosa cell expression of phosphatidylinositide 3-kinases (PI3K), serine-threonine kinase (Akt) and forkhead box O3 (Foxo3a) mRNA were measured by reverse transcribed and quantitative real-time polymerase chain reaction.ResultsSyndrome scores for pre- versus post-treatments decreased significantly (16.53±1.75 to 8.67±1.61) in the EA group (P<0.05), but showed no significant change in the control group (17.18±1.58 to 14.74±1.58). A significant difference in score change was found between the EA and control groups (P<0.05). High-quality embryo and clinical pregnancy rates were both increased in the EA group compared with the control group [69.15% (195/282) vs. 60.27% (176/292) and 66.67% (22/33) vs. 42.42% (14/33), respectively, P<0.05]. The fertilization rate was equivalent in EA and control groups. No difference was found in the number of retrieved oocytes between the two groups. Granulosa cell expression levels of PI3K and Akt mRNA were significantly increased in the EA group compared with the control group, while the expression of Foxo3a was reduced (all P<0.05).ConclusionsFor infertile patients with Shen deficiency syndrome undergoing IVF, EA for tonifying Shen as an adjunct treatment may alleviate clinical symptoms and improve the high-quality embryo rate. The EA-induced mechanism may involve regulation of PI3K/Akt/Foxo3a expression in granulosa cells to improve the developmental microenvironment of oocytes and inhibit granulosa cell apoptosis, possibly contributing to the improved clinical pregnancy rate (Registration No. ChiCTR 1800016217).

Muscle atrophy, a side effect from administration of the anti-inflammatory medication dexamethasone (DEX), is preventable by concomitant administration of the major monomeric constituent of Panax ginseng C.A. Meyer, 20(S)-ginsenoside Rg3 (S-Rg3). Putative S-Rg3-associated prevention of DEX-induced muscle atrophy may involve S-Rg3 mitigation of DEX-induced mitochondrial dysfunction. In the present study, MTT assays revealed enhanced cell viability following S-Rg3 treatment of DEX-injured C2C12 myotubes. Subsequent PCR and western blotting results demonstrated S-Rg3-induced reduction of expression of muscle atrophy F-box protein (atrogin-1) and muscle RING-finger protein-1, proteins previously linked to muscle atrophy. Additionally, S-Rg3 treatment of DEX-injured myotubes led to aggregation of Rg3 monomers in cells and dose-dependent increases in cellular mitochondrial basal respiratory oxygen consumption rate and intracellular ATP levels compared with their levels in untreated DEX-injured myotubes. In addition, S-Rg3 treatment significantly reversed DEX-induced reductions of expression of key mitochondrial respiratory electron transport chain subunits of protein complexes II, III and V in DEX-injured myotube cells. Furthermore, S-Rg3 alleviation of mitochondrial dysfunction associated with DEX-induced injury of C2C12 myotubes was linked to S-Rg3-associated decreases in both forkhead box O3 (FoxO3) protein expression and phosphorylation of AMP-activated protein kinase (AMPK). Collectively, these results implicate S-Rg3 modulation of signaling within the AMPK-FoxO3 pathway as a putative mechanism underlying S-Rg3 alleviation of DEX-induced muscle atrophy.

Osteoarthritis (OA) is a prevalent degenerative joint disease. This study combines bioinformatics analysis with in vivo and in vitro experiments to elucidate the molecular mechanisms through which melatonin (MT) regulates mitophagy to alleviate OA. Rat and chondrocyte OA models were established via anterior cruciate ligament transection or interleukin (IL)‐1β induction, followed by treatment with MT, Cyclosporine A (a mitophagy inhibitor), and 740Y‐P (a phosphatidylinositol‐3 kinase [PI3K] activator). Pathological changes in cartilage, histological scores, and cell apoptosis were evaluated alongside chondrocyte viability, apoptosis, mitochondrial morphology, mitochondrial membrane potential, and mitophagy using H&E and Safranin O‐fast green staining, Osteoarthritis Research Society International scoring (OARSI), TUNEL staining, CCK‐8, flow cytometry, transmission electron microscopy, JC‐1 staining, and immunofluorescence. Levels of inflammatory factors and mitophagy‐related protein levels were determined by ELISA and western blot. Bioinformatics analysis was applied to investigate the regulatory mechanisms of MT on mitophagy in OA. In vivo, MT mitigated OA by enhancing mitophagy and reducing apoptosis of cartilage cells. In vitro, MT attenuated IL‐1β‐induced chondrocyte apoptosis through mitophagy activation, and this effect was partially reversed by mitophagy inhibition. Mechanistically, the PI3K/protein kinase B (AKT)/forkhead box O3 (FoxO3) axis appeared to play a central role. MT suppressed PI3K/AKT signaling, thereby upregulating FoxO3 expression and promoting mitophagy, ultimately reducing chondrocyte apoptosis. Collectively, these findings suggest that MT enhances mitophagy via inhibition of the PI3K/AKT pathway, and subsequent upregulation of FoxO3, leading to reduced apoptosis of cartilage cells and attenuation of OA progression in rats.

FOXO3 is a member of the FOXO transcription factors thought to play a tumor-suppressor role in gastrointestinal cancer, while tumor-promoting function of FOXO3 has also been reported. These results suggest a context-dependent function of FOXO3 in tumor development. However, the relationship between the FOXO3 expression pattern and its role in tumorigenesis has not been elucidated. We examined the FOXO3 expression in 65 human primary gastric cancer and patient-derived xenograft tissues by immunohistochemistry and identified three subtypes according to subcellular localization: FOXO3-nuclear accumulated (FOXO3-Nuc), FOXO3-nuclear/cytoplasmic or cytoplasmic distributed (FOXO3-Cyt), and FOXO3-negative. In the FOXO3-Cyt gastric cancer cells, the expression of the constitutive active mutant FOXO3 (Act-ER FOXO3) induced the nuclear accumulation of FOXO3 and significantly suppressed colony formation and proliferation. The inhibition of the PI3K-AKT pathway by inhibitor treatment also suppressed the proliferation of FOXO3-Cyt gastric cancer cells, which was associated with the nuclear accumulation of endogenous FOXO3. Furthermore, the expression of Act-ER FOXO3 by an endogenous promoter significantly suppressed gastric tumorigenesis in Gan mice, a model of gastric cancer. Finally, treatment of FOXO3-Cyt human gastric cancer-derived organoids with an AKT inhibitor significantly suppressed the survival and proliferation. These results indicate that FOXO3 is a latent tumor suppressor for FOXO3-Cyt-type gastric cancer cells and that activation of the PI3K-AKT pathway protects this type of gastric cancer cell from FOXO3-mediated growth suppression via constitutive nuclear export. Thus, the inhibition of the PI3K-AKT pathway and nuclear translocation of endogenous FOXO3 may have therapeutic applications in the treatment of FOXO3-positive and cytoplasmic-type gastric cancer.