Transcription Factor Forkhead Box Research Articles

Lengthening the Guanidine-Aryl Linker of Phenylpyrimidinylguanidines Increases Their Potency as Inhibitors of FOXO3-Induced Gene Transcription.

Increased FOXO3 nuclear localization is involved in neuroblastoma chemoresistance and tumor angiogenesis. Accordingly, FOXO3 inhibition is a promising strategy for boosting antitumor immune responses and suppressing FOXO3-mediated therapy resistance in cancer cells. However, no FOXO3 inhibitors are currently available for clinical use. Nevertheless, we have recently identified (4-propoxy)phenylpyrimidinylguanidine as a FOXO3 inhibitor in cancer cells in the low micromolar range. Here, we report the synthesis and structure–activity relationship study of a small library of its derivatives, some of which inhibit FOXO3-induced gene transcription in cancer cells in a submicromolar range and are thus 1 order of magnitude more potent than their parent compound. By NMR and molecular docking, we showed that these compounds differ in their interactions with the DNA-binding domain of FOXO3. These results may provide a foundation for further optimizing (4-propoxy)phenylpyrimidinylguanidine and developing therapeutics for inhibiting the activity of forkhead box (FOX) transcription factors and their interactions with other binding partners.

Regulation and roles of FOXK2 in cancer.

Forkhead box K2 (FOXK2) is a member of the forkhead box transcription factor family that contains an evolutionarily conserved winged-helix DNA-binding domain. Recently, an increasing number of studies have demonstrated that FOXK2 plays an important role in the transcriptional regulation of cancer. Here, we provide an overview of the mechanisms underlying the regulation of FOXK2 expression and function and discuss the roles of FOXK2 in tumor pathogenesis. Additionally, we evaluated the prognostic value of FOXK2 expression in patients with various cancers. This review presents an overview of the different roles of FOXK2 in tumorigenesis and will help inform the design of experimental studies involving FOXK2. Ultimately, the information presented here will help enhance the therapeutic potential of FOXK2 as a cancer target.

In Vivo Application of CRISPR/Cas9 Revealed Implication of Foxa1 and Foxp1 in Prostate Cancer Proliferation and Epithelial Plasticity.

Simple SummaryProstate cancer is diagnosed in one out of eight men, with large implications on life quality. Forkhead box proteins are often found mutated in prostate cancer but their functions are still not fully understood. In this study, we applied CRISPR to investigate the function of two Forkhead box proteins, Foxa1 and Foxp1, in the mouse prostate in combination with loss of Pten. Our results reveal that Foxp1 is a tumor suppressor in prostate cancer progression by controlling proliferation and genes regulated by the androgen receptor. Foxa1 controls cell plasticity, as loss of Foxa1 converted the prostatic luminal cells to basal cells. Hereby, this study sheds light on two distinct functions of Forkhead box proteins in prostate cancer.Prostate cancer is the most common cancer in men in the Western world and the number is rising. Prostate cancer is notoriously heterogeneous, which makes it hard to generate and study in pre-clinical models. The family of Forkhead box (FOX) transcription factors are often altered in prostate cancer with especially high mutation burden in FOXA1 and FOXP1. FOXA1 harbors loss or gain of function mutations in 8% of prostate cancer, which increases to 14% in metastatic samples. FOXP1 predominately occurs with loss of function mutations in 7% of primary tumors, and similar incidents are found in metastatic samples. Here, we applied in vivo CRISPR editing, to study the loss of functions of these two FOX transcription factors, in murine prostate in combination with loss of Pten. Deficiency of Foxp1 increased proliferation in combination with loss of Pten. In contrast, proliferation was unchanged when androgen was deprived. The expression of Tmprss2 was increased when Foxp1 was mutated in vivo, showing that Foxp1 is a repressor for this androgen-regulated target. Furthermore, analysis of FOXP1 and TMPRSS2 expression in a human prostate cancer data set revealed a negative correlation. Mutation of Foxa1 in the murine prostate induces cell plasticity to luminal cells. Here, epithelial cells with loss of Foxa1 were transdifferentiated to cells with expression of the basal markers Ck5 and p63. Interestingly, these cells were located in the lumen and did not co-express Ck8. Overall, this study reveals that loss of Foxp1 increases cell proliferation, whereas loss of Foxa1 induces epithelial plasticity in prostate cancer.

Inhibition of the cardiac fibroblast-enriched histone methyltransferase Dot1L prevents cardiac fibrosis and cardiac dysfunction

BackgroundCardiac fibrosis is characterized by excessive extracellular matrix deposition that contributes to compromised cardiac function and potentially heart failure. Disruptor of telomeric silencing 1-like (Dot1L) is the catalytic enzyme required for histone H3K79 methylation which has been demonstrated to play a role in transcriptional activation. However, the functions of Dot1L in the process of cardiac fibrosis still remain unknown.ResultsIn the present study, we found that endogenous Dot1L is upregulated in cardiac fibroblasts (CFs) treated with angiotensin II (Ang II) or transforming growth factor (TGF)-β1, along with elevated extracellular matrix (ECM) such as fibronectin, collagen I and III. Silencing or inhibiting Dot1L mitigated Ang II-induced myofibroblast generation and fibrogenesis. We identified the transcription factor-forkhead box O (FoxO) 3a as a novel substrate of Dot1L, the transcriptional activating mark H3K79me3 level on the promoter of FoxO3a was increase in activated-CFs, and inhibition of Dot1L markedly decreased FoxO3a transcription accompanied by a significant decrease in the expression of fibrogenic gene. Knockdown of FoxO3a could alleviate ECM deposition induced by Ang II, on the contrary, overexpression FoxO3a resulting in CFs activation. Consistently, in vivo Dot1L ablation rescued myocardial ischemia-induced cardiac fibrosis and improved cardiac function.ConclusionsOur findings conclude that upregulation of Dot1L results in activation of the cardiac fibroblasts to promote profibrotic gene, eventually causes cardiac fibrosis. Pharmacological targeting for Dot1L might represent a promising therapeutic approach for the treatment of human cardiac fibrosis and other fibrotic diseases.

The Effects of Tamoxifen on Tolerogenic Cells in Cancer.

Simple SummaryTamoxifen is a very well-known hormonal therapy used to treat breast cancer patients. It works by blocking the effects of estrogen in breast tissue by competing with estradiol (E2) in the receptor site and binding to DNA to inhibit carcinogenesis. Moreover, it is less clarified that TAM is also involved indirectly via a Foxp3 knockout model through the CreER system to target specific immune checkpoints, especially checkpoints arising in cancer therapy. The suppressive function of tolerogenic cells is very important in the TME. Hence, in our study, we observed the effects of TAM on Tregs, in which it is involved indirectly via the CreER system. In addition, we also review the effects of TAM on other cells, which are MDSCs and DCs, that act by bridging the innate and adaptive immune systems.Tamoxifen (TAM) is the most prescribed selective estrogen receptor modulator (SERM) to treat hormone-receptor-positive breast cancer patients and has been used for more than 20 years. Its role as a hormone therapy is well established; however, the potential role in modulating tolerogenic cells needs to be better clarified. Infiltrating tumor-microenvironment-regulatory T cells (TME-Tregs) are important as they serve a suppressive function through the transcription factor Forkhead box P3 (Foxp3). Abundant studies have suggested that Foxp3 regulates the expression of several genes (CTLA-4, PD-1, LAG-3, TIM-3, TIGIT, TNFR2) involved in carcinogenesis to utilize its tumor suppressor function through knockout models. TAM is indirectly concomitant via the Cre/loxP system by allowing nuclear translocation of the fusion protein, excision of the floxed STOP cassette and heritable expression of encoding fluorescent protein in a cohort of cells that express Foxp3. Moreover, TAM administration in breast cancer treatment has shown its effects directly through MDSCs by the enrichment of its leukocyte populations, such as NK and NKT cells, while it impairs the differentiation and activation of DCs. However, the fundamental mechanisms of the reduction of this pool by TAM are unknown. Here, we review the vital effects of TAM on Tregs for a precise mechanistic understanding of cancer immunotherapies.

Protective mechanisms of loquat leaf extract and ursolic acid against diabetic pro-inflammation.

The pharmacological effectiveness of loquat leaf extract (LE) and its important component, ursolic acid (UA), in the treatment of diabetes mellitus, has been well established in traditional medicine; however, the mechanism underlying their action is still unclear. We evaluated the protective effects of LE and UA against hyperglycemia-induced advanced glycation end product (AGE) formations and hepatic pro-inflammation. Oral administration of UA and LE at a dose of 50mg/kg/day for 15days yielded no significant hypoglycemic effect in diabetic db/db mice. UA and LE suppressed hepatic oxidative stress and AGE formation in diabetic mice, and this was followed by the downregulated mitogen-activated protein kinase signaling and nuclear factor κ B (NF-κB) activity. To identify the molecular target of LE and UA, a docking simulation was performed, and this predicted UA to bind to liver kinase B1 (LKB1), an upstream of AMP-activated protein kinase (AMPK)/transcription factor forkhead box O3 (FOXO3) axis. UA reversed the high-glucose-induced downregulation of LKB1-AMPK1-FOXO3 activation and antioxidant gene transcription. These findings demonstrated the antioxidant and anti-inflammatory effects of UA and LE against hyperglycemia-induced hepatic inflammation. Furthermore, we speculate that the LKB1/AMPK/FOXO3 pathway is a potential target responsible for these beneficial effects of LE and UA.

The Essential Role of FoxO1 in the Regulation of Macrophage Function.

Macrophages are widely distributed in various tissues and organs. They not only participate in the regulation of innate and adaptive immune response, but also play an important role in tissue homeostasis. Dysregulation of macrophage function is closely related to the initiation, development and prognosis of multiple diseases, including infection and tumorigenesis. Forkhead box transcription factor O1 (FoxO1) is an important member among the forkhead box transcription factor family. Through directly binding to the promoter regions of downstream target genes, FoxO1 is implicated in cell proliferation, apoptosis, metabolic activities and other biological processes. In this review, we summarized the regulatory role of FoxO1 in macrophage phagocytosis, migration, differentiation and inflammatory activation. We also emphasized that macrophage reciprocally modulated FoxO1 activity via a post-translational modification (PTM) dominant manner.

Perspectives for Forkhead box transcription factors in diabetic cardiomyopathy: Their therapeutic potential and possible effects of salvianolic acids.

Diabetic cardiomyopathy (DCM) is the primary cause of morbidity and mortality in diabetic cardiovascular complications, which initially manifests as cardiac hypertrophy, myocardial fibrosis, dysfunctional remodeling, and diastolic dysfunction, followed by systolic dysfunction, and eventually end with acute heart failure. Molecular mechanisms underlying these pathological changes in diabetic hearts are complicated and multifactorial, including but not limited to insulin resistance, oxidative stress, lipotoxicity, cardiomyocytes apoptosis or autophagy, inflammatory response, and myocardial metabolic dysfunction. With the development of molecular biology technology, accumulating evidence illustrates that members of the class O of Forkhead box (FoxO) transcription factors are vital for maintaining cardiomyocyte metabolism and cell survival, and the functions of the FoxO family proteins can be modulated by a wide variety of post-translational modifications including phosphorylation, acetylation, ubiquitination, arginine methylation, and O-glycosylation. In this review, we highlight and summarize the most recent advances in two members of the FoxO family (predominately FoxO1 and FoxO3a) that are abundantly expressed in cardiac tissue and whose levels of gene and protein expressions change as DCM progresses, with the goal of providing valuable insights into the pathogenesis of diabetic cardiovascular complications and discussing their therapeutic potential and possible effects of salvianolic acids, a natural product.

Effect of Insulin Receptor on Juvenile Hormone Signal and Fecundity in Spodoptera litura (F.).

Simple SummaryThe tobacco cutworm, Spodoptera litura (F.), exemplifies strong reproductive capacities and damages many agricultural crops. The insulin signaling pathway is known as a key determinant of female reproduction in insects. However, the detailed molecular mechanisms in these processes are poorly studied. Here, we injected bovine insulin into the newly emerged moth, resulting in gene expression changes in the insulin pathway, while knockdown of SlInR caused an inverse gene expression change involved in the insulin pathway. Further studies indicated that the content of JH-III, Vg, total proteins and triacylgycerol could be suppressed by SlInR dsRNA injection. Furthermore, stunted ovaries and lower fecundity were observed by RNAi. Our studies indicated that SlInR plays a key role in JH-III synthesis and the ovarian development in S. litura.Insulin signaling can regulate various physiological functions, such as energy metabolism and reproduction and so on, in many insects, including mosquito and locust. However, the molecular mechanism of this physiological process remains elusive. The tobacco cutworm, Spodoptera litura, is one of the most important pests of agricultural crops around the world. In this study, phosphoinositide 3-kinase (SlPI3K), protein kinase B (SlAKT), target of rapamycin (SlTOR), ribosomal protein S6 kinase (SlS6K) and transcription factor cAMP-response element binding protein (SlCREB) genes, except transcription factor forkhead box class O (SlFoxO), can be activated by bovine insulin injection. Then, we studied the influence of the insulin receptor gene (SlInR) on the reproduction of S. litura using RNA interference technology. qRT-PCR analysis revealed that SlInR was most abundant in the head. The SlPI3K, SlAKT, SlTOR, SlS6K and SlCREB genes were decreased, except SlFoxO, after the SlInR gene knockdown. Further studies revealed that the expression of vitellogenin mRNA and protein, Methoprene-tolerant gene (SlMet), could be down-regulated by the injection of dsRNA of SlInR significantly. Furthermore, a depletion in the insulin receptor by RNAi significantly decreased the content of juvenile hormone III (JH-III), total proteins and triacylgycerol. These changes indicated that a lack of SlInR could impair ovarian development and decrease fecundity in S. litura. Our studies contribute to a comprehensive insight into reproduction, regulated by insulin and the juvenile hormone signaling pathway through nutrition, and a provide theoretical basis for the reproduction process in pest insects.

PGRMC1 Regulates Cellular Senescence via Modulating FOXO1 Expression in Decidualizing Endometrial Stromal Cells.

The appropriate differentiation of endometrial stromal cells (ESCs) into decidual cells is required for embryo implantation and subsequent placentation into humans. Decidualization is accompanied by the appearance of senescent-like cells. We recently reported the secretory phase-specific downregulation of endometrial progesterone receptor membrane component 1 (PGRMC1) and enhanced decidualization upon PGRMC1 knockdown and inhibition in cultured ESCs. However, it remains unknown whether PGRMC1 is involved in cellular senescence during decidualization. Here, we showed that the small interfering RNA (siRNA)-mediated knockdown of PGRMC1 and the inhibition of PGRMC1 by AG-205 increased the expression of the transcription factor forkhead box protein O1 (FOXO1) and the senescence-associated β-galactosidase activity in cAMP analog- and progesterone-treated ESCs. Furthermore, the knockdown of FOXO1 repressed the decidual senescence induced by siRNA-based PGRMC1 knockdown or AG-205 treatment. Taken together, the decreased PGRMC1 expression in ESCs may accelerate decidualization and cellular senescence via the upregulation of FOXO1 expression for appropriate endometrial remodeling and embryo implantation during the secretory phase.

Oncogenic Mutations in the DNA-Binding Domain of FOXO1 that Disrupt Folding: Quantitative Insights from Experiments and Molecular Simulations.

FOXO1, a member of the family of winged-helix motif Forkhead box (FOX) transcription factors, is the most abundantly expressed FOXO member in mature B cells. Sequencing of diffuse large B-cell lymphoma (DLBCL) tumors and cell lines identified specific mutations in the forkhead domain linked to loss of function. Differential scanning calorimetry and thermal shift assays were used to characterize how eight of these mutations affect the stability of the FOX domain. Mutations L183P and L183R were found to be particularly destabilizing. Electrophoresis mobility shift assays show these same mutations also disrupt FOXO1 binding to their canonical DNA sequences, suggesting that the loss of function is due to destabilization of the folded structure. Computational modeling of the effect of mutations on FOXO1 folding was performed using alchemical free energy perturbation (FEP), and a Markov model of the entire folding reaction was constructed from massively parallel molecular simulations, which predicts folding pathways involving the late folding of helix α3. Although FEP can qualitatively predict the destabilization from L183 mutations, we find that a simple hydrophobic transfer model, combined with estimates of unfolded-state solvent-accessible surface areas from molecular simulations, is able to more accurately predict changes in folding free energies due to mutations. These results suggest that the atomic detail provided by simulations is important for the accurate prediction of mutational effects on folding stability. Corresponding disease-associated mutations in other FOX family members support further experimental and computational studies of the folding mechanism of FOX domains.

FOXM1 Is a Novel Molecular Target of AFP-Positive Hepatocellular Carcinoma Abrogated by Proteasome Inhibition.

Alpha-fetoprotein (AFP) is an oncofetal protein that is elevated in a subset of hepatocellular carcinoma (HCC) with poor prognosis, but the molecular target activated in AFP-positive HCC remains elusive. Here, we demonstrated that the transcription factor forkhead box M1 (FOXM1) is upregulated in AFP-positive HCC. We found that FOXM1 expression was highly elevated in approximately 40% of HCC cases, and FOXM1-high HCC was associated with high serum AFP levels, a high frequency of microscopic portal vein invasion, and poor prognosis. A transcriptome and pathway analysis revealed the activation of the mitotic cell cycle and the inactivation of mature hepatocyte metabolism function in FOXM1-high HCC. The knockdown of FOXM1 reduced AFP expression and induced G2/M cell cycle arrest. We further identified that the proteasome inhibitor carfilzomib attenuated FOXM1 protein expression and suppressed cell proliferation in AFP-positive HCC cells. Carfilzomib in combination with vascular endothelial growth factor receptor 2 (VEGFR2) blockade significantly prolonged survival by suppressing AFP-positive HCC growth in a subcutaneous tumor xenotransplantation model. These data indicated that FOXM1 plays a pivotal role in the proliferation of AFP-positive liver cancer cells. Carfilzomib can effectively inhibit FOXM1 expression to inhibit tumor growth and could be a novel therapeutic option in patients with AFP-positive HCC who receive anti-VEGFR2 antibodies.

Hepatic p53 is regulated by transcription factor FOXO1 and acutely controls glycogen homeostasis

The tumor suppressor p53 is involved in the adaptation of hepatic metabolism to nutrient availability. Acute deletion of p53 in the mouse liver affects hepatic glucose and triglyceride metabolism. However, long-term adaptations upon the loss of hepatic p53 and its transcriptional regulators are unknown. Here we show that short-term, but not chronic, liver-specific deletion of p53 in mice reduces liver glycogen levels, and we implicate the transcription factor forkhead box O1 protein (FOXO1) in the regulation of p53 and its target genes. We demonstrate that acute p53 deletion prevents glycogen accumulation upon refeeding, whereas a chronic loss of p53 associates with a compensational activation of the glycogen synthesis pathway. Moreover, we identify fasting-activated FOXO1 as a repressor of p53 transcription in hepatocytes. We show that this repression is relieved by inactivation of FOXO1 by insulin, which likely mediates the upregulation of p53 expression upon refeeding. Strikingly, we find that high-fat diet–induced insulin resistance with persistent FOXO1 activation not only blunted the regulation of p53 but also the induction of p53 target genes like p21 during fasting, indicating overlapping effects of both FOXO1 and p53 on target gene expression in a context-dependent manner. Thus, we conclude that p53 acutely controls glycogen storage in the liver and is linked to insulin signaling via FOXO1, which has important implications for our understanding of the hepatic adaptation to nutrient availability.

Immune Evasion and Drug Resistance Mediated by USP22 in Cancer: Novel Targets and Mechanisms.

Regulation of ubiquitination is involved in various processes in cancer occurrence and development, including cell cycle arrest, cell proliferation, apoptosis, invasion, metastasis, and immunity. Ubiquitination plays an important role not only at the transcriptional and post-translational levels but also at the protein level. When ubiquitination is in a pathological state, abnormally activated biological processes will not only induce cancer progression but also induce immune evasion. The main function of deubiquitinases (DUBs) is to remove ubiquitin chains from substrates, changing the biological activity of the substrates. It has great potential to improve the prognosis of cancer by targeting DUB to regulate proteome. Ubiquitin-specific peptidase 22 (USP22) belongs to the ubiquitin-specific protease (USP) family of DUBs and has been reported to be related to various physiological and pathological processes. USP22 is abnormally expressed in various malignant tumors such as prostate cancer, lung cancer, liver cancer, and colorectal cancer, which suggests that USP22 may play an important role in tumors. USP22 may stabilize programmed death ligand 1 (PD-L1) by deubiquitination while also regulating T-cell infiltration into tumors. Regulatory T cells (Tregs) are a unique class of immunosuppressive CD4+ T cells that primarily suppress the immune system by expressing the master transcription factor forkhead box protein 3 (FOXP3). USP22 was found to be a positive regulator of stable FOXP3 expression. Treg-specific ablation of USP22 leads to reduced tumor volume in multiple cancer models. This suggests that USP22 may regulate tumor resistance to immunotherapy. In this article, we review and summarize the biological functions of USP22 in multiple signal transduction pathways during tumorigenesis, immune evasion, and drug resistance. Furthermore, we propose a new possibility of combining USP22 with chemotherapeutic, targeted, and immunosuppressive drugs in the treatment of cancer.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

Bifidobacterium infantis regulates the programmed cell death 1 pathway and immune response in mice with inflammatory bowel disease

BACKGROUNDInflammatory bowel disease (IBD) is caused by an abnormal immune response. Programmed cell death 1 (PD-1) is an immunostimulatory molecule, which interacts with PD ligand (PD-L1) playing a prime important role among autoimmune diseases. Bifidobacterium infantis (B. infantis) can promote the differentiation of CD (cluster of differentiation) 4+ T cells into regulatory T cells (Tregs). Tregs participate in the development of IBD and may be related to disease activity. B. infantis amplify the expression level of PD-1, PD-L1 and Tregs’ nuclear transcription factor forkhead box protein 3 (Foxp3). But the mechanism of B. infantis on PD-1/PD-L1 signaling remains unclear.AIMTo explore the mechanism of B. infantis regulating the immune response in IBD.METHODSForty-eight-week-old BALB/c mice were randomly divided into five groups: The control group, dextran sulphate sodium (DSS) model group, DSS + B. infantis group, DSS + B. infantis + anti-PD-L1 group, and DSS + anti-PD-L1 group. The control group mice were given drinking water freely, the other four groups were given drinking water containing 5% DSS freely. The control group, DSS model group, and DSS + anti-PD-L1 group were given normal saline (NS) 400 μL daily by gastric lavage, and the DSS + B. infantis group and DSS + B. infantis + anti-PD-L1 group were given NS and 1 × 109 colony-forming unit of B. infantis daily by gastric lavage. The DSS + B. infantis + anti-PD-L1 group and DSS + anti-PD-L1 group were given 200 μg of PD-L1 blocker intraperitoneally at days 0, 3, 5, and 7; the control group, DSS + anti-PD-L1 group, and DSS + B. infantis group were given an intraperitoneal injection of an equal volume of phosphate buffered saline (PBS). Changes in PD-L1, PD-1, Foxp3, interleukin (IL)-10, and transforming growth factor β (TGF-β) 1 protein and gene expression were observed. Flow cytometry was used to observe changes in CD4+, CD25+, Foxp3+ cell numbers in the blood and spleen.RESULTSCompared to the control group, the expression of PD-1, Foxp3, IL-10, and TGF-β1 was significantly decreased in the intestinal tract of the DSS mice (P < 0.05). Compared to the control group, the proportion of CD4+, CD25+, Foxp3+ cells in spleen and blood of DSS group was visibly katabatic (P < 0.05). B. infantis upgraded the express of PD-L1, PD-1, Foxp3, IL-10, and TGF-β1 (P < 0.05) and increased the proportion of CD4+, CD25+, Foxp3+ cells both in spleen and blood (P < 0.05). After blocking PD-L1, the increase in Foxp3, IL-10, and TGF-β1 protein and gene by B. infantis was inhibited (P < 0.05), and the proliferation of CD4+, CD25+, Foxp3+ cells in the spleen and blood was also inhibited (P < 0.05). After blocking PD-L1, the messenger ribonucleic acid and protein expression of PD-1 were invariant.CONCLUSIONIt is potential that B. infantis boost the proliferation of CD4+, CD25+, Foxp3+ T cells in both spleen and blood, as well as the expression of Foxp3 in the intestinal tract by activating the PD-1/PD-L1 pathway.

The Function of FoxK Transcription Factors in Diseases.

Forkhead box (FOX) transcription factors play a crucial role in the regulation of many diseases, being an evolutionarily conserved superfamily of transcription factors. In recent years, FoxK1/2, members of its family, has been the subject of research. Even though FoxK1 and FoxK2 have some functional overlap, increasing evidence indicates that the regulatory functions of FoxK1 and FoxK2 are not the same in various physiological and disease states. It is important to understand the biological function and mechanism of FoxK1/2 for better understanding pathogenesis of diseases, predicting prognosis, and finding new therapeutic targets. There is, however, a lack of comprehensive and systematic analysis of the similarities and differences of FoxK1/2 roles in disease, prompting us to perform a literature review.

Human FOXP3 and tumour microenvironment.

The tumour microenvironment (TME) is a complex system composed of cancer cells, stromal cells and immune cells. Regulatory T cells (Tregs) in the TME impede immune surveillance of tumours and suppress antitumor immune responses. Transcription factor forkhead box protein 3 (FOXP3) is the main marker of Tregs, which dominates the function of Tregs. FOXP3 was originally thought to be a Tregs-specific expression molecule, and recent studies have found that FOXP3 is expressed in a variety of tumours with inconsistent functional roles. This review summarizes the recent progress of infiltrating Treg-FOXP3 and tumour-FOXP3 in TME, discusses the communication mechanism between FOXP3+ cells and effector T cells in TME, the relationship between FOXP3 and clinical prognosis, and the potential of FOXP3-targeted therapy.

FOXO3a‑modulated DEPDC1 promotes malignant progression of nephroblastoma via the Wnt/β‑catenin signaling pathway.

DEP domain containing 1 (DEPDC1) and forkhead box transcription factor 3a (FOXO3a) serve a role in tumor cells. To the best of our knowledge, however, the expression of DEPDC1 and FOXO3a in nephroblastoma and their role and potential mechanisms in nephroblastoma cells have not been reported. The aim of the present study was to characterize the expression of DEPDC1 and FOXO3a in nephroblastoma, as well as the underlying mechanisms. The expression levels of DEPDC1 and FOXO3a were detected using reverse transcription-quantitative PCR and western blotting. Cell viability, proliferation, invasion and migration were detected using Cell Counting Kit-8, colony formation, Transwell and wound healing assays, respectively. The activity of DEPDC1 promoter was detected by dual-luciferase reporter assay and the association between FOXO3a and DEPDC1 was detected using immunoprecipitation. DEPDC1 expression was significantly increased in nephroblastoma cells, particularly WiT49 cells. Compared with the negative control, DEPDC1 knockdown significantly inhibited proliferation, invasion and migration of WiT49 cells, while DEPDC1 overexpression (Ov) reversed these effects. By contrast, expression of FOXO3a was decreased in WiT49 cells and immunoprecipitation showed that FOXO3a bound to the DEPDC1 promoter. Ov-FOXO3a inhibited WiT49 cell proliferation, invasion and migration, as well as protein expression levels of phosphorylated-glycogen synthase kinase-3β, Wnt3a and β-catenin, while DEPDC1 Ov reversed the inhibitory effects of FOXO3a Ov on WiT49 cells. In conclusion, DEPDC1 promoted malignant progression of nephroblastoma via the Wnt/β-catenin signaling pathway; this may be regulated by FOXO3a.

Examination of the role of the forkhead box L2 (Foxl2) in gonadal and embryonic development in the boring giant clam Tridacna crocea

Tridacna crocea, the smallest and earliest sexually maturing giant clam species, harbours important ecological value in maintaining coral reefs and holds potential for development as an ornamental species. At present, the molecular mechanism of gonadal development of this species remains largely unclear, and this hinders its artificial breeding and subsequent resource proliferation. The transcription factor forkhead box L subfamily member 2 (FoxL2) is one of the most conserved genes involved in the process of ovarian differentiation and development in many vertebrates and invertebrates. In this study, the Foxl2 gene (Tc-Foxl2) was cloned and characterized from T. crocea for the first time. The ORF of Tc-Foxl2 cDNA encoded a putative protein of 384 amino acid residues with a deduced molecular mass of 43.39 kDa and a theoretical isoelectric point (pI) of 8.92. Phylogenetic analysis indicated that the amino acid sequence of Tc-Foxl2 contained a typical FH domain and clustered with molluscan Foxl2 homologues. Tc-Foxl2 was mainly expressed in the gonads of females and hermaphroditic individuals but was fairly low in the gonads of males and resting individuals. Quantitative RT–PCR revealed that the expression of Tc-Foxl2 mRNA was significantly upregulated during vitellogenesis, while in situ hybridization indicated that Tc-Foxl2 mRNA was mainly detectable in follicle cells in the ovary. Furthermore, RNAi-mediated Tc-Foxl2 knockdown impeded the further growth of oocytes on the 14th day postinjection in the process of early vitellogenesis. Whole-mount in situ hybridization and qRT–PCR analyses demonstrated that during embryonic development, Tc-Foxl2 mRNA had a conserved expression profile, which may be involved in the formation of primordial germ cells. These results collectively suggest that Tc-Foxl2 is a female-biased gene that is involved in the vitellogenesis and embryonic development in Tridacna crocea.