FOXO3a represses VEGF expression through FOXM1-dependent and -independent mechanisms in breast cancer

FOXM1 c.1205 C > A mutation is associated with unilateral Moyamoya disease and inhibits angiogenesis in human brain endothelial cells

Unilateral moyamoya disease (MMD) represents a distinct subtype characterised by occlusive changes in the circle of Willis and abnormal vascular network formation. However, the aetiology and pathogenesis of unilateral MMD remain unclear. In this study, genetic screening of a family with unilateral MMD using whole-genome sequencing helped identify the c.1205 C > A variant of FOXM1, which encodes the transcription factor FOXM1 and plays a crucial role in angiogenesis and cell proliferation, as a susceptibility gene mutation. We demonstrated that this mutation significantly attenuated the proangiogenic effects of FOXM1 in human brain endothelial cells, leading to reduced proliferation, migration, and tube formation. Furthermore, FOXM1 c.1205 C > A results in increased apoptosis of human brain endothelial cells, mediated by the downregulation of the transcription of the apoptosis-inhibiting protein BCL2. These results suggest a potential role for the FOXM1 c.1205 C > A mutation in the pathogenesis of unilateral MMD and may contribute to the understanding and treatment of this condition.

Decrease in GPSM2 mediated by the natural product luteolin contributes to colon adenocarcinoma treatment and increases the sensitivity to fluorouracil

Luteolin, a monomeric substance, is a natural product of the Brucea javanica (BJ) plant. Brucea javanica oil emulsion injection (BJOEI) is a proprietary Chinese medicine purified from BJ that is widely used clinically as an anti-tumor treatment. Although a growing body of research suggests that luteolin and BJOEI have anti-tumor effects, the molecular mechanism of action has not been fully elucidated. In this study, through molecular docking technology, we found that luteolin can interact directly with GPSM2 and regulate the FoxO signaling pathway through GPSM2. In addition, the inhibitory effect of luteolin on colon adenocarcinoma (COAD) cells was found to be offset by knockdown of GPSM2. In contrast, the anti-proliferative effects of luteolin could be notably reversed by overexpression of GPSM2. The results reveal that GPSM2 is crucial in luteolin-mediated anti-proliferative effects. The mediation of anti-proliferative effects by GPSM2 has also been indirectly demonstrated in RKO and SW480 xenograft mice models. In addition, we verified that BJOEI inhibits the progression of COAD by mediating GPSM2 and regulating the FoxO signaling pathway. We also found that BJOEI achieved a better anti-tumor effect when combined with fluorouracil injection. Collectively, our data show that the anti-tumor effects of BJOEI and luteolin on COAD are GPSM2-dependent and downregulating the expression of GPSM2 to regulate the FoxO signaling pathway may be an effective way to treat COAD.

LncRNAs as nodes for the cross-talk between autophagy and Wnt signaling in pancreatic cancer drug resistance

Pancreatic cancer is a malignancy with high mortality. In addition to the few symptoms until the disease reaches an advanced stage, the high fatality rate is attributed to its rapid development, drug resistance and lack of appropriate treatment. In the selection and research of therapeutic drugs, gemcitabine is the first-line drug for pancreatic cancer. Solving the problem of gemcitabine resistance in pancreatic cancer will contribute to the progress of pancreatic cancer treatment. Long non coding RNAs (lncRNAs), which are RNA transcripts longer than 200 nucleotides, play vital roles in cellular physiological metabolic activities. Currently, our group and others have found that some lncRNAs are aberrantly expressed in pancreatic cancer cells, which can regulate the process of cancer through autophagy and Wnt/β-catenin pathways simultaneously and affect the sensitivity of cancer cells to therapeutic drugs. This review presents an overview of the recent evidence concerning the node of lncRNA for the cross-talk between autophagy and Wnt/β-catenin signaling in pancreatic cancer, together with the practicability of lncRNAs and the core regulatory factors as targets in therapeutic resistance.

Linagliptin, a DPP-4 inhibitor, activates AMPK/FOXO3a and suppresses NFκB to mitigate the debilitating effects of diethylnitrosamine exposure in rat liver: Novel mechanistic insights

Accumulating evidence suggests that dysregulation of FOXO3a plays a significant role in the progression of various malignancies, including hepatocellular carcinoma (HCC). FOXO3a inactivation, driven by oncogenic stimuli, can lead to abnormal cell growth, suppression of apoptosis, and resistance to anticancer drugs. Therefore, FOXO3a emerges as a potential molecular target for the development of innovative treatments in the era of oncology. Linagliptin (LNGTN), a DPP-4 inhibitor known for its safe profile, has exhibited noteworthy anti-inflammatory and anti-oxidative properties in previous in vivo studies. Several potential molecular mechanisms have been proposed to explain these effects. However, the capacity of LNGTN to activate FOXO3a through AMPK activation has not been investigated. In our investigation, we examined the potential repurposing of LNGTN as a hepatoprotective agent against diethylnitrosamine (DENA) intoxication. Additionally, we assessed LNGTN's impact on apoptosis and autophagy. Following a 10-week administration of DENA, the liver underwent damage marked by inflammation and early neoplastic alterations. Our study presents the first experimental evidence demonstrating that LNGTN can reinstate the aberrantly regulated FOXO3a activity by elevating the nuclear fraction of FOXO3a in comparison to the cytosolic fraction, subsequent to AMPK activation. Moreover, noteworthy inactivation of NFκB induced by LNGTN was observed. These effects culminated in the initiation of apoptosis, the activation of autophagy, and the manifestation of anti-inflammatory, antiproliferative, and antiangiogenic outcomes. These effects were concomitant with improved liver function and microstructure. In conclusion, our findings open new avenues for the development of novel therapeutic strategies targeting the AMPK/FOXO3a signaling pathway in the management of chronic liver damage.

FOXM1 Participates in Trophoblast Migration and Early Trophoblast Invasion: Potential Role in Blastocyst Implantation

Successful implantation requires coordinated migration and invasion of trophoblast cells into a receptive endometrium. Reduced forkhead box M1 (FOXM1) expression limits trophoblast migration and angiogenesis in choriocarcinoma cell lines, and in a rat model, placental FOXM1 protein expression was significantly upregulated in the early stages of pregnancy compared to term pregnancy. However, the precise role of FOXM1 in implantation events remains unknown. By analyzing mice blastocysts at embryonic day (E3.5), we have demonstrated that FOXM1 is expressed as early as the blastocyst stage, and it is expressed in the trophectoderm of the blastocyst. Since controlled oxygen tension is determinant for achieving normal implantation and placentation and a chronic hypoxic environment leads to shallow trophoblast invasion, we evaluated if FOXM1 expression changes in response to different oxygen tensions in the HTR-8/SVneo first trimester human trophoblast cell line and observed that FOXM1 expression was significantly higher when trophoblast cells were cultured at 3% O2, which coincides with oxygen concentrations in the uteroplacental interface at the time of implantation. Conversely, FOXM1 expression diminished in response to 1% O2 that resembles a hypoxic environment in utero. Migration and angiogenesis were assessed following FOXM1 knockdown and overexpression at 3% O2 and 1% O2, respectively, in HTR-8/SVneo cells. FOXM1 overexpression increased transmigration ability and tubule formation. Using a 3D trophoblast invasion model with trophospheres from HTR-8/SVneo cells cultured on a layer of MATRIGEL and of mesenchymal stem cells isolated from menstrual fluid, we observed that trophospheres obtained from 3D trophoblast invasion displayed higher FOXM1 expression compared with pre-invasion trophospheres. Moreover, we have also observed that FOXM1-overexpressing trophospheres increased trophoblast invasion compared with controls. HTR-8/SVneo-FOXM1-depleted cells led to a downregulation of PLK4, VEGF, and MMP2 mRNA expression. Our current findings suggest that FOXM1 participates in embryo implantation by contributing to trophoblast migration and early trophoblast invasion, by inducing transcription activation of genes involved in these processes. Maternal-fetal communication is crucial for trophoblast invasion, and maternal stromal cells may induce higher levels of FOXM1 in trophoblast cells.

FOXO3a-interacting proteins' involvement in cancer: a review

Due to its role in apoptosis, differentiation, cell cycle arrest, and DNA damage repair in stress responses (oxidative stress, hypoxia, chemotherapeutic drugs, and UV irradiation or radiotherapy), FOXO3a is considered a key tumor suppressor that determines radiotherapeutic and chemotherapeutic responses in cancer cells. Mutations in the FOXO3a gene are rare, even in cancer cells. Post-translational regulations are the main mechanisms for inactivating FOXO3a. The subcellular localization, stability, transcriptional activity, and DNA binding affinity for FOXO3a can be modulated via various post-translational modifications, including phosphorylation, acetylation, and interactions with other transcriptional factors or regulators. This review summarizes how proteins that interact with FOXO3a engage in cancer progression.

IKBKE regulates angiogenesis by modulating VEGF expression and secretion in glioblastoma

PURPOSE

As a noncanonical inflammatory kinase, IKBKE is frequently overexpressed and activated and has been identified as an oncogenic protein in glioblastoma. However, the potential function and underlying mechanism of IKBKE contributing to tumor angiogenesis remain elusive.

METHODS

First, we analyzed the correlation between IKBKE and VEGF expression in glioma samples by immunohistochemistry (IHC). Second, HUVEC-related assays and Western blot were used to detect the regulatory effect of IKBKE on angiogenesis by modulating VEGF expression. Third, IKBKE depletion could alleviate the influence of VEGF expression on IHC of intracranial glioma model.

RESULTS

We demonstrate that depletion of IKBKE markedly inhibits tumor growth and angiogenesis in glioblastoma. Mechanistically, IKBKE induces VEGF expression and secretion by regulating AKT/FOXO3a in glioblastoma.

CONCLUSIONS

This study reveals that IKBKE is a novel oncogenic molecule that induces angiogenesis through the promotion of VEGF expression and highlights the potential of targeting IKBKE for glioblastoma therapy.

Heparanase-mediated histone 3 acetylation regulates VEGF gene transcription in the hyperglycemia and hypoxia human retinal endothelial cells

Heparanase (HPA) is believed that might mediate histone 3 lysine 9 acetylation (H3K9ac) to regulate vascular endothelial growth factor (VEGF) gene expressions in the hyperglycemia and hypoxia human retinal endothelial cells (HRECs). Cultured human retinal endothelial cells (HRECs) in hyperglycemia, hypoxia, siRNA, and normal medium, respectively. Distributions of H3K9ac and HPA in HRECs were analyzed by immunofluorescence. Western blot and real-time PCR were respectively used to evaluate the expression of HPA, H3K9ac, and VEGF. The differences in occupancies of H3K9ac and RNA polymerase II at VEGF gene promoter among three groups were studied by Chromatin immunoprecipitation (ChIP) combined with real-time PCR. Co-immunoprecipitation (Co-IP) was used to measure the status of HPA and H3K9ac. Re-ChIP was used to verify whether HPA and H3K9ac associate to the transcription of VEGF gene. HPA was consistent with that of H3K9ac in the hyperglycemia and hypoxia groups. And the fluorescent lights of H3K9ac and HPA in siRNA groups were similar to the control group, fainter than that of hyperglycemia, hypoxia, and non-silencing groups. Western blot results showed that the expressions of HPA, H3K9ac, and VEGF in hyperglycemia and hypoxia HRECs were statistically higher than that of the control. HPA, H3K9ac, and VEGF expressions in siRNA groups were statistically lower than hyperglycemia and hypoxia HRECs. The same trends also were found in real-time PCR. ChIP exhibited the occupancies of H3K9ac and RNA Pol II at VEGF gene promoter in hyperglycemia and hypoxia groups were significantly more increased than in the control group. Co-IP revealed that HPA combined with H3K9ac in hyperglycemia and hypoxia groups; while it was not discovered in the control group. Re-ChIP showed that HPA combined with H3K9ac at VEGF gene promoter in the hyperglycemia and hypoxia HRECs nuclear. In our study HPA can influence expressions of H3K9ac and VEGF in the hyperglycemia and hypoxia HRECs. HPA can probably combine with H3K9ac and regulate the transcription of the VEGF gene in the hyperglycemia and hypoxia HRECs.

The Role of Polo-Like Kinase 1 in Regulating the Forkhead Box Family Transcription Factors

Polo-like kinase 1 (PLK1) is a serine/threonine kinase with more than 600 phosphorylation substrates through which it regulates many biological processes, including mitosis, apoptosis, metabolism, RNA processing, vesicle transport, and G₂ DNA-damage checkpoint recovery, among others. Among the many PLK1 targets are members of the FOX family of transcription factors (FOX TFs), including FOXM1, FOXO1, FOXO3, and FOXK1. FOXM1 and FOXK1 have critical oncogenic roles in cancer through their antagonism of apoptotic signals and their promotion of cell proliferation, metastasis, angiogenesis, and therapeutic resistance. In contrast, FOXO1 and FOXO3 have been identified to have broad functions in maintaining cellular homeostasis. In this review, we discuss PLK1-mediated regulation of FOX TFs, highlighting the effects of PLK1 on the activity and stability of these proteins. In addition, we review the prognostic and clinical significance of these proteins in human cancers and, more importantly, the different approaches that have been used to disrupt PLK1 and FOX TF-mediated signaling networks. Furthermore, we discuss the therapeutic potential of targeting PLK1-regulated FOX TFs in human cancers.

Heat shock proteins and cancer: The FoxM1 connection

Heat shock proteins (Hsp) and FoxM1 have significant roles in carcinogenesis. According to their relative molecular weight, Hsps are divided into Hsp110, Hsp90, Hsp70, Hsp60, Hsp40, and small Hsps. Hsp70 can play essential functions in cancer initiation and is overexpressed in several human cancers. Hsp70, in combination with cochaperones HIP and HOP, refolds partially denatured proteins and acts as a cochaperone for Hsp90. Also, Hsp70, in combination with BAG3, regulates the FoxM1 signaling pathway. FoxM1 protein is a transcription factor of the Forkhead family that is overexpressed in most human cancers and is involved in many cancers' development features, including proliferation, migration, invasion, angiogenesis, metastasis, and resistance to apoptosis. This review discusses the Hsp70, Hsp90, and FoxM1 structure and function, the known Hsp70 cochaperones, and Hsp70, Hsp90, and FoxM1 inhibitors.

Increased Sparc release from subchondral osteoblasts promotes articular chondrocyte degeneration under estrogen withdrawal

OBJECTIVE

The incidence of osteoarthritis (OA) in menopausal women is significantly higher than in same-aged men. Investigating the role of subchondral osteoblasts in estrogen deficiency-induced OA may help elucidate the pathological mechanism, providing new insights for the diagnosis and treatment of menopausal OA.

METHODS

A classical ovariectomy-induced OA (OVX-OA) rat model was utilized to isolate primary articular chondrocytes and subchondral osteoblasts, which were identified and then cocultured in Transwell. The expression of chondrocyte anabolic and catabolic indicators was evaluated. The differentially expressed proteins in the conditioned medium (CM) of osteoblasts were identified by Liquid Chromatograph-Mass Spectrometer (LC-MS/MS). Normal chondrocytes were treated with osteoblast CM, and then RNA sequencing was performed on the treated chondrocytes. KEGG was used to identify significant enrichment of signaling pathways, and Simple Western was used to verify the expression of related proteins in the signaling pathways.

RESULTS

Coculture of OVX-OA subchondral osteoblasts with chondrocytes significantly downregulated the expression of the anabolic indicators and upregulated the expression of the catabolic indicators in chondrocytes. 1,601 proteins were identified in both normal and OVX osteoblast culture supernatants. Protein-protein interaction network analysis revealed that Sparc was one of the hub proteins. The AMPK/Foxo3a signaling pathway of chondrocytes was downregulated by OVX-OA osteoblasts CM. AICAR, the AMPK agonist, partially reversed the catabolic effect of OVX-OA osteoblasts on chondrocytes.

CONCLUSIONS

Sparc secreted by OVX-OA subchondral osteoblasts can downregulate the AMPK/Foxo3a signaling pathway of chondrocytes, thereby promoting chondrocyte degeneration.

Rational Combinations of PARP Inhibitors with HRD-Inducing Molecularly Targeted Agents

Cancers with wild-type BRCA, homologous recombination proficiency, or de novo or acquired resistance to PARP inhibition represent a growing population of patients who may benefit from combinatorial PARP inhibitor strategies. We review targeted inhibitors of angiogenesis, epigenetic regulators, and PI3K, MAPK, and other cellular signaling pathways as inducers of homologous recombination deficiency, providing support for the use of PARP inhibitors in contexts not previously considered susceptible to PARP inhibition.

Structure-based virtual screening identified novel FOXM1 inhibitors as the lead compounds for ovarian cancer

Ovarian cancer (OC) is a gynecological tumor with possibly the worst prognosis, its 5-year survival rate being only 47.4%. The first line of therapy prescribed is chemotherapy consisting of platinum and paclitaxel. The primary reason for treatment failure is drug resistance. FOXM1 protein has been found to be closely associated with drug resistance, and inhibition of FOXM1 expression sensitizes cisplatin-resistant ovarian cancer cells. Combining existing first-line chemotherapy drugs with FOXM1 prolongs the overall survival of patients, therefore, FOXM1 is considered a potential therapeutic target in ovarian cancer. Previous research conducted by our team revealed a highly credible conformation of FOXM1 which enables binding by small molecules. Based on this conformation, the current study conducted virtual screening to determine a new structural skeleton for FOXM1 inhibitors which would enhance their medicinal properties. DZY-4 showed the highest affinity towards FOXM1, and its inhibitory effect on proliferation and migration of ovarian cancer at the cellular level was better than or equal to that of cisplatin, while its efficacy was equivalent to that of cisplatin in a nude mouse model. In this study, the anti-tumor effect of DZY-4 is reported for the first time. DZY-4 shows potential as a drug that can be used for ovarian cancer treatment, as well as a drug lead for future research.

Nutrition regulates the expression of storage proteins in Bombyx mori via insulin-like/FoxO signaling pathway

Insect serum proteins, also termed storage proteins (SPs), are hexamer proteins that form amino acid reservoirs important for the development of pupae and embryos in most insects. In this study, we investigated the SP genes expression and regulation pathways in silkworms (Bombyx mori). We observed that B. mori SPs (BmSPs) in the fat body of larvae were strongly decreased by starvation, suggesting they respond to nutrition deprivation. Further, we examined the relationship between BmSP expression and the insulin-like signaling pathway (ILS) to study the regulation of BmSPs expression. The results showed that insulin up-regulated the expression of BmSPs, but an inhibitor of the ILS pathway protein PI3K downregulated the expression of BmSPs in B. mori larvae. Similar results were observed in cultured fat body in vitro and BmE cells. We then over-expressed FoxO, an ILS transcriptional factor, in BmE cells and B. mori larvae to further verify the regulatory role of ILS on expression of BmSPs and found BmFoxO negatively regulates the expression of BmSPs in both BmE cells and larvae. Moreover, BmFoxO was dephosphorylated and translocated from the cytoplasm to the nucleus under starvation treatment. Finally, an element on -2627-2644 bp upstream of the transcription start site of BmSP1 was identified as the binding site of BmFoxO by electrophoretic mobility shift assay and verified by chromatin immunoprecipitation. In summary, our results indicate that nutrient uptake triggers the expression of BmSPs via the ILS/FoxO signaling pathway. This study provides a reference for further study on the expression and regulation of insect SP genes.

Laminarin Attenuates ROS-Mediated Cell Migration and Invasiveness through Mitochondrial Dysfunction in Pancreatic Cancer Cells

Background: Pancreatic ductal adenocarcinoma (PDAC) is a notoriously aggressive type of cancer with a high metastasis rate. It is conventionally treated by surgical resection and neoadjuvant chemotherapy. However, continuous chemotherapy leads to relapse in most PDAC patients due to chemical resistance. Therefore, novel anticancer agents need to be identified and developed. The antitumor activities of laminarin extracted from brown algae against hepatocarcinoma, lung, and colon cancer have been established. However, its effects on pancreatic cancer have remained obscure. Purpose: Our study identified the anticancer effects of laminarin on pancreatic cancer cells and tried to explain its intracellular mechanisms. Methods: We assessed the cell viability of PANC-1 and MIA PaCa-2 cells using MTT assay. Hanging drop method was used for the spheroid formation. Flow cytometry was conducted to evaluate the several intracellular alterations including apoptosis, ROS production, mitochondrial membrane potential (MMP), and calcium concentration induced by laminarin. An invasion test was performed to assess the inhibitory effect of laminarin on cell migration and the invasive genes were evaluated by RT-qPCR. Signaling pathway related with anticancer effects of laminarin was analyzed by western blot. Results: We report that inhibiting laminarin increased the proliferation and viability of the representative pancreatic cancer cell lines, MIA PaCa-2 and PANC-1. Laminarin triggered apoptosis and mitochondrial impairment as evidenced by depolarized mitochondrial membranes, disrupted calcium, and suppressed cell migration caused by reactive oxygen species production and related intracellular signaling pathways. Moreover, laminarin showed synergistic effects when combined with 5-FU, a standard anticancer agent for PDAC. Conclusion: The present study is the first to report that laminarin exerts anticancer effect through ROS production in pancreatic cancer cells. Laminarin shows potential to serve as a new anticancer agent for treating PDAC.

Structure-based virtual screening towards the discovery of novel FOXM1 inhibitors

Aim: Given the importance of FOXM1 in the treatment of ovarian cancer, we aimed to identify an excellent specific inhibitor and examined its underlying therapeutic effect. Materials & methods: The binding statistics for FDI-6 with FOXM1 were calculated through computer-aided drug design (CADD). We selected XST-119 through virtual screening, performed surface plasmon resonance and in vitro cell antiproliferative activity analysis and evaluated its antitumor efficacy in a mouse model. Results: XST-119 had significantly higher affinity for FOXM1 and antiproliferative activity than FDI-6. XST-119 had a definite inhibitory activity in a xenograft mouse model. Conclusion: We identified XST-119, a FOXM1 inhibitor, with better efficacy for treatment of ovarian cancer. FOXM1 binding sites for small molecules are also highlighted, which may provide the foundation for further drug discovery.

Establishing and Validating an Aging-Related Prognostic Four-Gene Signature in Colon Adenocarcinoma

Background

Aging is a process that biological changes accumulate with time and lead to increasing susceptibility to diseases like cancer. This study is aimed at establishing an aging-related prognostic signature in colon adenocarcinoma (COAD).

Methods

The transcriptome data and clinical variables of COAD patients were downloaded from TCGA database. The genes in GOBP_AGING gene set was used for prognostic evaluation by the univariate and multivariate Cox regression analyses. The model was presented by a nomogram and assessed by the Kaplan-Meier curves and calibration curves. The drug response and gene mutation were also performed to implicate the clinical significance. The GO and KEGG analyses were employed to unravel the potential functional mechanism.

Results

The Gene Set Enrichment Analysis result indicates that GOBP_AGING pathway is significantly enriched in COAD samples. Four aging-related genes are finally used to construct the aging-related prognostic signature: FOXM1, PTH1R, KL, and CGAS. The COAD patients with high risk score have much shorter overall survival in both train cohort and test cohort. The nomogram is then assembled to predict 1-year, 3-year, and 5-year survival. Patients with high risk score have elevated infiltrating B cell naïve and attenuated cisplatin sensitivity. The mutation landscape shows that the TTN, FAT4, ZFHX4, APC, and OBSCN gene mutation are different between high risk score patients and low risk score patients. The differentially expressed genes between patients with high score and low score are enriched in B cell receptor signaling pathway.

Conclusion

We constructed an aging-related signature in COAD patients, which can predict oncological outcome and optimize therapeutic strategy.

A narrative review of research progress on FoxM1 in breast cancer carcinogenesis and therapeutics

OBJECTIVE

The purpose of this review is to clarify the potential roles of forkhead box transcription factor M1 (FoxM1) in the occurrence and progression of breast cancer, as well as the predictive value of FoxM1 as a prognostic biomarker and potential therapeutic target for breast cancer.

BACKGROUND

Breast cancer, well-known as a molecularly heterogeneous cancer, is still one of the most frequently diagnosed malignant tumors among females worldwide. Tumor recurrence and metastasis are the central causes of high mortality in breast cancer patients. Many factors contribute to the occurrence and progression of breast cancer, including FoxM1. FoxM1, widely regarded as a classic proliferation-related transcription factor, plays pivotal roles in the occurrence, proliferation, invasion, migration, drug resistance, and epithelial-mesenchymal transition (EMT) processes of multiple human tumors including breast cancer.

METHODS

The PubMed database was searched for articles published in English from February 2008 to May 2021 using related keywords such as "forkhead box transcription factor M1", "human breast cancer", "FoxM1", and "human tumor". About 90 research papers and reports written in English were identified, most of which were published after 2015. These papers mainly concentrated on the functions of FoxM1 in the occurrence, development, drug resistance, and treatment of human breast cancer.

CONCLUSIONS

Considering that the abnormal expression of FoxM1 plays a significant role in the proliferation, invasion, metastasis, and chemotherapy drug resistance of breast cancer, and its overexpression is closely correlated with the unfavorable clinicopathological characteristics of breast tumor patients, it is considerably important to comprehend the regulatory mechanism of FoxM1 in breast cancer. This will provide strong evidence for FoxM1 as a potential biomarker for the targeted treatment and prognostic evaluation of breast cancer patients.

Targeting Histone Modifications in Breast Cancer: A Precise Weapon on the Way

Histone modifications (HMs) contribute to maintaining genomic stability, transcription, DNA repair, and modulating chromatin in cancer cells. Furthermore, HMs are dynamic and reversible processes that involve interactions between numerous enzymes and molecular components. Aberrant HMs are strongly associated with tumorigenesis and progression of breast cancer (BC), although the specific mechanisms are not completely understood. Moreover, there is no comprehensive overview of abnormal HMs in BC, and BC therapies that target HMs are still in their infancy. Therefore, this review summarizes the existing evidence regarding HMs that are involved in BC and the potential mechanisms that are related to aberrant HMs. Moreover, this review examines the currently available agents and approved drugs that have been tested in pre-clinical and clinical studies to evaluate their effects on HMs. Finally, this review covers the barriers to the clinical application of therapies that target HMs, and possible strategies that could help overcome these barriers and accelerate the use of these therapies to cure patients.

Resistance to Intervention: Paclitaxel in Breast Cancer

Breast cancer stands as the most prevalent cancer in women globally, and contributes to the highest percentage of mortality due to cancer-related deaths in women. Paclitaxel (PTX) is heavily relied on as a frontline chemotherapy drug in breast cancer treatment, especially in advanced metastatic cancer. Generation of resistance to PTX often derails clinical management and adversely affects patient outcomes. Understanding the molecular mechanism of PTX resistance is necessary to device methods to aid in overcoming the resistance. Recent studies exploring the mechanism of development of PTX resistance have led to unveiling of a range novel therapeutic targets. PTX resistance pathways that involve major regulatory proteins/RNAs like RNF8/Twist/ROR1, TLR, ErbB3/ErbB2, BRCA1- IRIS, MENA, LIN9, MiRNA, FoxM1 and IRAK1 have expanded the complexity of resistance mechanisms, and brought newer insights into the development of drug targets. These resistance-related targets can be dealt with synthetic/natural therapeutics in combination with PTX. The present review encompasses the recent understanding of PTX resistance mechanisms in breast cancer and possible therapeutic combinations to overcome resistance.

MiR-223-3p targets FOXO3a to inhibit radiosensitivity in prostate cancer by activating glycolysis

AIMS

The incidence and detection rate of prostate cancer in China have been increasing in recent years. Radiotherapy is the ideal treatment for non-metastatic prostate cancer (PCa), but the effectiveness of radiotherapy is greatly discounted due to radio resistance. Therefore, relieving the radiotherapy resistance of PCa is key to improve the clinical efficacy of PCA.

MAIN METHODS

Cell proliferation was estimated using the MTT and clone formation assays. Cell apoptosis was estimated using the Annexin V-FITC/propidium iodide (PI) staining assay. Glucose uptake and lactose and ATP production were used to detect glycolysis.

KEY FINDINGS

miR-223-3p was significantly upregulated in clinically collected urine samples and PCa cells with low radiosensitivity. Enhancing miR-223-3p reduced radiosensitivity further, while inhibiting miR-223-3p improved the radiosensitivity of PC3 and LNCaP cells. Importantly, miR-223-3p regulated radiosensitivity by enhancing cell glycolysis. FOXO3a was a key target of miRNA-223-3p regulating glycolysis and radiosensitivity. Overexpression of FOXO3a abated the glycolysis level and alleviated the radioresistance caused by enhancing miR-223-3p to a certain extent.

SIGNIFICANCE

This is novel research on the role of miR-223-3p in promoting radiotherapy resistance of PCa cells by activating glycolysis. This approach provides a new perspective and ideas for alleviating radiotherapy resistance of PCa cells.

FOXM1: A Multifunctional Oncoprotein and Emerging Therapeutic Target in Ovarian Cancer

Forkhead box M1 (FOXM1) is a member of the conserved forkhead box (FOX) transcription factor family. Over the last two decades, FOXM1 has emerged as a multifunctional oncoprotein and a robust biomarker of poor prognosis in many human malignancies. In this review article, we address the current knowledge regarding the mechanisms of regulation and oncogenic functions of FOXM1, particularly in the context of ovarian cancer. FOXM1 and its associated oncogenic transcriptional signature are enriched in >85% of ovarian cancer cases and FOXM1 expression and activity can be enhanced by a plethora of genomic, transcriptional, post-transcriptional, and post-translational mechanisms. As a master transcriptional regulator, FOXM1 promotes critical oncogenic phenotypes in ovarian cancer, including: (1) cell proliferation, (2) invasion and metastasis, (3) chemotherapy resistance, (4) cancer stem cell (CSC) properties, (5) genomic instability, and (6) altered cellular metabolism. We additionally discuss the evidence for FOXM1 as a cancer biomarker, describe the rationale for FOXM1 as a cancer therapeutic target, and provide an overview of therapeutic strategies used to target FOXM1 for cancer treatment.

Prognostic Significance of ACP5 in Human Gastric Cancer

INTRODUCTION

Tartrate-resistant acid phosphatase (ACP5) plays crucial roles in multiple pathological processes, including the genesis and progression of malignant tumors. We performed this study with the purpose of determining whether ACP5 is a crucial biomarker significantly related to prognoses of gastric cancer (GC) patients.

METHODS

The expression level of ACP5 level was assessed among 170 GC specimens using immunohistochemistry. The associations between ACP5 expression and clinicopathological variables were evaluated. Univariate and multivariate Cox regression analyses were performed to confirm independent prognostic factors for GC patients.

RESULTS

It was revealed that ACP5 expression level in GC tissue was significantly associated with depth of invasion (p = 0.029) and TNM stage (p = 0.036). ACP5 was demonstrated by multivariate Cox regression analysis to be an independent prognostic factor for overall survival (OS) (p = 0.001) and recurrence-free survival (RFS) (p = 0.011) of GC patients.

CONCLUSIONS

The expression of ACP5 in GC tissue was significantly higher than that in normal tissues, and its overexpression was associated with a poorer prognosis, suggesting its potential roles in preventing and treating GC.

MiR-940 promotes malignant progression of breast cancer by regulating FOXO3

Breast cancer (BC) is a common cancer with poor survival. The present study aimed to explore the effect of miR-940 on the process of BC cells and its target gene FOXO3. The expression of miR-940 was assessed in BC tissues and cells using qRT-PCR. Furthermore, the correlation between miR-940 and prognosis of BC patients from the TCGA database was analyzed. CCK8 assays and colony formation assays were used to explore the effect of miR-940 on BC cell proliferation. The invasion abilities were detected by transwell assays. Luciferase reporter assay was performed to scrutinize the relationship between miR-940 and FOXO3. Finally, rescue experiments were performed through FOXO3 down-regulation and miR-940 inhibitors by using CCK8 assays, colony formation assays and transwell assays. miR-940 was significantly up-regulated in BC cells and tissues. In addition, the high level of miR-940 correlated with poor survival of BC patients (P=0.023). CCK8 assays, colony formation assays and transwell assays indicated that miR-940 promoted the proliferation and invasion abilities of BC cells. The luciferase reporter assay suggested that miR-940 directly targeted FOXO3. Moreover, we found that the effect of si-FOXO3 was rescued by miR-940 inhibitors in BC cells. miR-940 may promote the proliferation and invasion abilities of BC cells by targeting FOXO3. Our study suggested that miR-940 could be a novel molecular target for therapies against BC.

Suicide gene therapy-mediated purine nucleoside phosphorylase/fludarabine system for in vitro breast cancer model with emphasis on evaluation of vascular endothelial growth factor promoter efficacy

In this study, a suicide gene therapy approach was optimized by a non-viral polyplex system based on pEGFP-N1 vector harboring purine nucleoside phosphorylase gene conducted by vascular endothelial growth factor promoter for an in vitro breast cancer model (4T1 cell line). The VEGF promoter and purine nucleoside phosphorylase gene were cloned into the vector from the source of 4T1 and E. coli genomic DNA, respectively. A gene construct was developed by replacing VEGF promoter instead of CMV promoter in pEGFP-N1vector. PNP gene was integrated in to the multiple cloning site of the obtained vector. On the other hand, a construct from pEGFP-N1 harboring PNP gene under the control of the original CMV promoter was developed. The transfection method using cationic polymer was optimized based on N/P ratio, cell cytotoxicity, polyplex size, zeta potential and the green fluorescent protein (GFP) expression by fluorescent microscopy and flowcytometry. Also, the effect of hypoxia condition induced by 0.5 mM H₂O₂ on the promoter efficiency was investigated. The results showed that the performed gene delivery system is capable of the gene transfection to more than 30% of the cancer cells with both VEGF-PNP-pEGFP-N1 and PNP-pEGFP-N1 plasmids. The hypoxia condition did not show a significant effect on the VEGF promoter. But, it revealed that bystander effect can improve the efficacy of this system and reduce drug IC50 to 2 and fourfold for plasmids VEGF-PNP-pEGFP-N1 and PNP-pEGFP-N1, respectively. These results showed that the bystander effect could almost compensate the low efficiency of non-viral gene delivery systems. We suggest that the tumor-specific gene expression system mediated by the VEGF promoter can be especially useful in the present model of breast cancer gene therapy.

Aberrantly high activation of a FoxM1-STMN1 axis contributes to progression and tumorigenesis in FoxM1-driven cancers

Fork-head box protein M1 (FoxM1) is a transcriptional factor which plays critical roles in cancer development and progression. However, the general regulatory mechanism of FoxM1 is still limited. STMN1 is a microtubule-binding protein which can inhibit the assembly of microtubule dimer or promote depolymerization of microtubules. It was reported as a major responsive factor of paclitaxel resistance for clinical chemotherapy of tumor patients. But the function of abnormally high level of STMN1 and its regulation mechanism in cancer cells remain unclear. In this study, we used public database and tissue microarrays to analyze the expression pattern of FoxM1 and STMN1 and found a strong positive correlation between FoxM1 and STMN1 in multiple types of cancer. Lentivirus-mediated FoxM1/STMN1-knockdown cell lines were established to study the function of FoxM1/STMN1 by performing cell viability assay, plate clone formation assay, soft agar assay in vitro and xenograft mouse model in vivo. Our results showed that FoxM1 promotes cell proliferation by upregulating STMN1. Further ChIP assay showed that FoxM1 upregulates STMN1 in a transcriptional level. Prognostic analysis showed that a high level of FoxM1 and STMN1 is related to poor prognosis in solid tumors. Moreover, a high co-expression of FoxM1 and STMN1 has a more significant correlation with poor prognosis. Our findings suggest that a general FoxM1-STMN1 axis contributes to cell proliferation and tumorigenesis in hepatocellular carcinoma, gastric cancer and colorectal cancer. The combination of FoxM1 and STMN1 can be a more precise biomarker for prognostic prediction.

FOXO transcription factor family in cancer and metastasis

Forkhead box O (FOXO) transcription factors regulate diverse biological processes, affecting development, metabolism, stem cell maintenance and longevity. They have also been increasingly recognised as tumour suppressors through their ability to regulate genes essential for cell proliferation, cell death, senescence, angiogenesis, cell migration and metastasis. Mechanistically, FOXO proteins serve as key connection points to allow diverse proliferative, nutrient and stress signals to converge and integrate with distinct gene networks to control cell fate, metabolism and cancer development. In consequence, deregulation of FOXO expression and function can promote genetic disorders, metabolic diseases, deregulated ageing and cancer. Metastasis is the process by which cancer cells spread from the primary tumour often via the bloodstream or the lymphatic system and is the major cause of cancer death. The regulation and deregulation of FOXO transcription factors occur predominantly at the post-transcriptional and post-translational levels mediated by regulatory non-coding RNAs, their interactions with other protein partners and co-factors and a combination of post-translational modifications (PTMs), including phosphorylation, acetylation, methylation and ubiquitination. This review discusses the role and regulation of FOXO proteins in tumour initiation and progression, with a particular emphasis on cancer metastasis. An understanding of how signalling networks integrate with the FOXO transcription factors to modulate their developmental, metabolic and tumour-suppressive functions in normal tissues and in cancer will offer a new perspective on tumorigenesis and metastasis, and open up therapeutic opportunities for malignant diseases.

FOXO3a-driven miRNA signatures suppresses VEGF-A/NRP1 signaling and breast cancer metastasis

Metastasis remains the major obstacle to improved survival for breast cancer patients. Downregulation of FOXO3a transcription factor in breast cancer is causally associated with the development of metastasis through poorly understood mechanisms. Here, we report that FOXO3a is functionally related to the inhibition of VEGF-A/NRP1 signaling and to the consequent suppression of breast cancer metastasis. We show that FOXO3a directly induces miR-29b-2 and miR-338 expression. Ectopic expression of miR-29b-2/miR-338 significantly suppresses EMT, migration/invasion, and in vivo metastasis of breast cancer. Moreover, we demonstrate that miR-29b-2 directly targets VEGF-A while miR-338 directly targets NRP1, and show that regulation of miR-29b-2 and miR-338 mediates the ability of FOXO3a to suppress VEGF-A/NRP1 signaling and breast cancer metastasis. Clinically, our results show that the FOXO3a-miR-29b-2/miR-338-VEGF-A/NRP1 axis is dysregulated and plays a critical role in disease progression in breast cancer. Collectively, our findings propose that FOXO3a functions as a metastasis suppressor, and define a novel signaling axis of FOXO3a-miRNA-VEGF-A/NRP1 in breast cancer, which might be potential therapeutic targets for breast cancer.

Vagus nerve stimulation optimized cardiomyocyte phenotype, sarcomere organization and energy metabolism in infarcted heart through FoxO3A-VEGF signaling

Vagus nerve stimulation (VNS) restores autonomic balance, suppresses inflammation action and minimizes cardiomyocyte injury. However, little knowledge is known about the VNS’ role in cardiomyocyte phenotype, sarcomere organization, and energy metabolism of infarcted hearts. VNS in vivo and acetylcholine (ACh) in vitro optimized the levels of α/β-MHC and α-Actinin positive sarcomere organization in cardiomyocytes while reducing F-actin assembly of cardiomyocytes. Consistently, ACh improved glucose uptake while decreasing lipid deposition in myocytes, correlating both with the increase of Glut4 and CPT1α and the decrease of PDK4 in infarcted hearts in vivo and myocytes in vitro, attributing to improvement in both glycolysis by VEGF-A and lipid uptake by VEGF-B in response to Ach. This led to increased ATP levels accompanied by the repaired mitochondrial function and the decreased oxygen consumption. Functionally, VNS improved the left ventricular performance. In contrast, ACh-m/nAChR inhibitor or knockdown of VEGF-A/B by shRNA powerfully abrogated these effects mediated by VNS. On mechanism, ACh decreased the levels of nuclear translocation of FoxO3A in myocytes due to phosphorylation of FoxO3A by activating AKT. FoxO3A overexpression or knockdown could reverse the specific effects of ACh on the expression of VEGF-A/B, α/β-MHC, Glut4, and CPT1α, sarcomere organization, glucose uptake and ATP production. Taken together, VNS optimized cardiomyocytes sarcomere organization and energy metabolism to improve heart function of the infarcted heart during the process of delaying and/or blocking the switch from compensated hypertrophy to decompensated heart failure, which were associated with activation of both P13K/AKT-FoxO3A-VEGF-A/B signaling cascade.

Mitotic Spindle Apparatus Abnormalities in Chronic Obstructive Pulmonary Disease Cells: A Potential Pathway to Lung Cancer

Chronic obstructive pulmonary disease (COPD) is a long-term lung disease characterized by irreversible lung damage resulting in airflow limitation, abnormal permanent air-space enlargement, and emphysema. Cigarette smoking is the major cause of COPD with 15% to 30% of smokers developing either disease. About 50% to 80% of patients with lung cancer have preexisting COPD and smokers who have COPD are at an increased risk for developing lung cancer. Therefore, COPD is considered an independent risk for lung cancer, even after adjusting for smoking. A crucial early event in carcinogenesis is the induction of the genomic instability through alterations in the mitotic spindle apparatus. To date, the underlying mechanism by which COPD contributes to lung cancer risk is unclear. We hypothesized that tobacco smoke carcinogens induce mitotic spindle apparatus abnormalities and alter expression of crucial genes leading to increased genomic instability and ultimately tumorigenesis. To test our hypothesis, we assessed the genotoxic effects of a potent tobacco-smoke carcinogen [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, (NNK)] on bronchial epithelial cells from patients with COPD and normal bronchial epithelial cells and identified genes associated with mitotic spindle defects and chromosome missegregation that also overlap with lung cancer. Our results indicate that exposure to NNK leads to a significantly altered spindle orientation, centrosome amplification, and chromosome misalignment in COPD cells as compared with normal epithelial cells. In addition, we identified several genes (such as AURKA, AURKB, and MAD2L2) that were upregulated and overlap with lung cancer suggesting a potential common pathway in the transition from COPD to lung cancer.

Reciprocal regulation between GCN2 (eIF2AK4) and PERK (eIF2AK3) through the JNK-FOXO3 axis to modulate cancer drug resistance and clonal survival

Pharmaceutical inhibitors of the endoplasmic reticulum (ER)-stress modulator PERK (eIF2AK3) have demonstrated anticancer activities in combination therapies, but their effectiveness as a single agent is limited, suggesting the existence of possible compensatory cellular responses. To explore the potential mechanisms involved, we performed time-course drug treatment experiments on the parental MCF-7 and drug resistant MCF-7Epi^R and MCF-7Tax^R breast cancer cells and identified GCN2 (eIF2AK4) as a molecule that can potentially cooperate with PERK to regulate FOXO3 via JNK and AKT to modulate drug response. Consistently, GCN2 knockdown severely impaired the clonal survival of parental and resistant MCF-7 cells and sensitised them to epirubicin and paclitaxel treatment. Western blot, RT-qPCR and ChIP analyses also confirmed that GCN2 inactivation causes an induction of JNK and thereby FOXO3 activity, culminating in an increase in PERK activity and expression at the transcription level. Conversely, PERK-inactivation using GSK2606414-induces an induction in GCN2 expression and activity also associated with JNK. In agreement, we also showed that the perk^-/- MEFs, expressing elevated levels of P-JNK, JNK, GCN2 and reduced levels of P-AKT and P-FOXO3, have lower clonogenicity and are more sensitive to epirubicin compared to wild-type MEFs. Similarly, gcn2^-/- MEFs expressing augmented levels of P-JNK, JNK, P-PERK, PERK and lower levels of P-AKT and P-FOXO3 also had lower clonogenicity and were more sensitive to epirubicin and PERK-inhibition. In addition, JNK1/2 deletion in MEFs resulted in reduced levels of GCN2, FOXO3, PERK, P-PERK expression as well as FOXO3 activity and enhanced clonal survival and resistance to PERK-inhibition. Together these results demonstrate that GCN2 cooperates with PERK through the JNK-FOXO3 axis in a reciprocal negative feedback loop to mediate cancer chemotherapeutic drug response and clonal survival, advocating the potential of targeting GCN2 as a therapeutic strategy for treating cancer and for overcoming drug resistance.

[Quantitative proteomics and bioinformatics analyses of human coronary artery endothelial cell injury induced by Kawasaki disease]

OBJECTIVE

To study the biomarkers for human coronary artery endothelial cell (HCAEC) injury induced by Kawasaki disease (KD) using isobaric tags for relative and absolute quantitation (iTRAQ) proteomics.

METHODS

HCAECs cultured with the serum of children with KD were used as the KD group, and those cultured with the serum of healthy children was used as the healthy control group. The iTRAQ technique was used to measure the expression of proteins in two groups. The data on proteins were analyzed by bioinformatics. Western blot was used for the validation of protein markers.

RESULTS

A total of 518 significantly differentially expressed proteins were identified (with an absolute value of difference fold of >1.2, P<0.05). The gene ontology analysis showed that the differentially expressed proteins were significantly enriched in biological processes (including cellular processes, metabolic processes, and biological regulation), cellular components (including cell parts, cells, and organelles), and molecular functions (including binding, catalytic activity, and molecular function regulators). The KEGG analysis showed that the proteins were significantly enriched in the signaling pathways of ribosomes, PI3K-Akt signaling pathway, and transcriptional dysregulation in cancer. The PPI network showed that the top 9 protein markers in relation density were PWP2, MCM4, MCM7, MCM5, MCM3, MCM2, SLD5, HDAC2, and MCM6, which were selected as the protein markers for coronary endothelial injury in KD. Western blot showed that the KD group had significantly lower expression levels of the protein markers HDAC2, PWP2, and MCM2 than the healthy control group (P<0.05).

CONCLUSIONS

The serum of children with KD significantly changes the protein expression pattern of HCAECs and affects the signaling pathways associated with the cardiovascular system, which provides a new basis for the pathophysiological mechanism and therapeutic targets of KD.

Role of FOXO Transcription Factors in Cancer Metabolism and Angiogenesis

Forkhead box O transcription factors (FOXOs) regulate several signaling pathways and play crucial roles in health and disease. FOXOs are key regulators of the expression of genes involved in multiple cellular processes and their deregulation has been implicated in cancer. FOXOs are generally considered tumor suppressors and evidence also suggests that they may have a role in the regulation of cancer metabolism and angiogenesis. In order to continue growing and proliferating, tumor cells have to reprogram their metabolism and induce angiogenesis. Angiogenesis refers to the process of new blood capillary formation from pre-existing vessels, which is an essential driving force in cancer progression and metastasis through supplying tumor cells with oxygen and nutrients. This review summarizes the roles of FOXOs in the regulation of cancer metabolism and angiogenesis. A deeper knowledge of the involvement of FOXOs in these two key processes involved in cancer dissemination may help to develop novel therapeutic approaches for cancer treatment.

A three layered histone epigenetics in breast cancer metastasis

Thanks to the advancement in science and technology and a significant number of cancer research programs being carried out throughout the world, the prevention, prognosis and treatment of breast cancer are improving with a positive and steady pace. However, a stern thoughtful attention is required for the metastatic breast cancer cases—the deadliest of all types of breast cancer, with a character of relapse even when treated. In an effort to explore the less travelled avenues, we summarize here studies underlying the aspects of histone epigenetics in breast cancer metastasis. Authoritative reviews on breast cancer epigenetics are already available; however, there is an urgent need to focus on the epigenetics involved in metastatic character of this cancer. Here we put forward a comprehensive review on how different layers of histone epigenetics comprising of histone chaperones, histone variants and histone modifications interplay to create breast cancer metastasis landscape. Finally, we propose a hypothesis of integrating histone-epigenetic factors as biomarkers that encompass different breast cancer subtypes and hence could be exploited as a target of larger population.

Poly(1-vinylimidazole) polyplexes as novel therapeutic gene carriers for lung cancer therapy

The present work explores the ability of poly(1-vinylimidazole) (PVI) to complex small interfering RNA (siRNA) silencing vascular endothelial growth factor (VEGF) and the in vitro efficiency of the formed complexes in A549 lung cancer cells. The polyplex formed was found to exhibit 66% complexation efficiency. The complexation was confirmed by gel retardation assays, FTIR and thermal analysis. The blank PVI polymer was not toxic to cells. The polyplex was found to exhibit excellent internalization and escaped the endosome effectively. The polyplex was more effective than free siRNA in silencing VEGF in lung cancer cells. The silencing of VEGF was quantified using Western blot and was also reflected in the depletion of HIF-1α levels in the cells treated with the polyplex. VEGF silencing by the polyplex was found to augment the cytotoxic effects of the chemotherapeutic agent 5-fluorouracil. Microarray analysis of the mRNA isolated from cells treated with free siRNA and the polyplex reveal that the VEGF silencing by the polyplex also altered the expression levels of several other genes that have been connected to the proliferation and invasion of lung cancer cells. These results indicate that the PVI complexes can be an effective agent to counter lung cancer.

Increased hydrostatic pressure induces nuclear translocation of DAF-16/FOXO in C. elegans

Mechanical stimulation is well known to be important for maintaining tissue and organ homeostasis. Here, we found that hydrostatic pressure induced nuclear translocation of a forkhead box O (FOXO) transcription factor DAF-16, in C. elegans within minutes, whereas the removal of this pressure resulted in immediate export of DAF-16 to the cytoplasm. We also monitored DAF-16-dependent transcriptional changes by exposure to 1 MPa pressure for 5 min, and found significant changes in collagen and other genes in a DAF-16 dependent manner. Lifespan was markedly prolonged with exposure to cyclic pressure treatment (1 MPa once a day for 5 min from L1 larvae until death). Furthermore, age-dependent decline in locomotor activity was suppressed by the treatment. In contrast, the nuclear translocation of the yes-associated protein YAP-1 was not induced under the same pressure conditions. Thus, moderate hydrostatic pressure improves ageing progression through activation of DAF-16/FOXO in C. elegans.

MicroRNA-132 suppresses migration and invasion of renal carcinoma cells

BACKGROUND

The aim of this study was to explain the effects of microRNA-132 in renal cell carcinoma by regulating FOXM1 expression.

METHODS

Thirty patients with renal cell carcinoma admitted to our hospital were enrolled, and their adjacent normal tissues and cancer tissues were taken. The expression of microRNA-132 was measured by in situ hybridization (ISH) and RT-PCR, and the expression of FOXM1 was evaluated by RT-PCR and immunohistochemistry (IHC), and the correlation between microRNA-132 and FOXM1 was analyzed. In the cell experiment, the KETR-3 cells were divided into three groups: Negative control (NC) group were treated with nothing; blank (BL) group were transfected with empty vector; and microRNA-132 (miRNA) group were transfected with microRNA-132. The cell invasion and migration abilities among groups were assessed by transwell and wound healing assays. The expression levels of related proteins (FOXM1, MMP-2, MMP-9, VEGF-alpha, and uPAR) were determined by Western blot.

RESULTS

Depending on clinical data, we found that FOXM1 protein expression of renal cell carcinoma tissues was higher than that in adjacent normal tissues. MiRNA-132 was negative correlation with FOXM1. In vitro, the number of invasive cells and wound healing rate in the microRNA group were significantly suppressed than those in the NC group (P < 0.05, respectively). In the Western blot assay, the results showed that the protein expression levels of FOXM1, MMP-2, MMP-9, VEGF-α, and uPAR were significantly inhibited in the miRNA group compared with the NC group (P < 0.05, respectively).

CONCLUSION

miRNA-132 had anti-tumor effects in renal cell carcinoma by suppressing FOXM1 expression.

Lapatinib sensitivity in nasopharyngeal carcinoma is modulated by SIRT2-mediated FOXO3 deacetylation

Background

Chemoresistance is an obstacle to the successful treatment of nasopharyngeal carcinoma (NPC). Lapatinib is a targeted tyrosine kinase inhibitor therapeutic drug also used to treat NPC, but high doses are often required to achieve a result. To investigate the mechanism for the development of Lapatinib resistance, we characterised a number of NPC cell lines to determine the role of FOXO3 and sirtuins in regulating NPC resistance.

Methods

Sulforhodamine B (SRB) assays, Clonogenic assays, Protein extraction, quantification and western blotting, RT qPCR, Co-immunoprecipitation assay.

Results

To explore novel treatment strategies, we first characterized the Lapatinib-sensitivity of a panel of NPC cell lines by SRB and clonogenic cytotoxic assays and found that the metastatic NPC (C666–1 and 5-8F) cells are highly resistant whereas the poorly metastatic lines (6-10B, TW01 and HK-1) are sensitive to Lapatinib. Western blot analysis of the Lapatinib-sensitive 6-10B and resistant 5-8F NPC cells showed that the expression of phosphorylated/inactive FOXO3 (P-FOXO3;T32), its target FOXM1 and its regulator SIRT2 correlate negatively with Lapatinib response and sensitivity, suggesting that SIRT2 mediates FOXO3 deacetylation to promote Lapatinib resistance. In agreement, clonogenic cytotoxic assays using wild-type and foxo1/3/4^−/− mouse embryonic fibroblasts (MEFs) showed that FOXO1/3/4-deletion significantly attenuates Lapatinib-induced cytotoxicity, confirming that FOXO proteins are essential for mediating Lapatinib response. SRB cell viability assays using chemical SIRT inhibitors (i.e. sirtinol, Ex527, AGK2 and AK1) revealed that all SIRT inhibitors can reduce NPC cell viability, but only the SIRT2-specific inhibitors AK1 and AGK2 further enhance the Lapatinib cytotoxicity. Consistently, clonogenic assays demonstrated that the SIRT2 inhibitors AK1 and AGK2 as well as SIRT2-knockdown increase Lapatinib cytotoxicity further in both the sensitive and resistant NPC cells. Co-immunoprecipitation studies showed that besides Lapatinib treatment, SIRT2-pharmaceutical inhibition and silencing also led to an increase in FOXO3 acetylation. Importantly, SIRT2 inhibition and depletion further enhanced Lapatinib-mediated FOXO3-acetylation in NPC cells.

Conclusion

Collectively, our results suggest the involvement of SIRT2-mediated FOXO3 deacetylation in Lapatinib response and sensitivity, and that SIRT2 can specifically antagonise the cytotoxicity of Lapatinib through mediating FOXO3 deacetylation in both sensitive and resistant NPC cells. The present findings also propose that SIRT2 can be an important biomarker for metastatic and Lapatinib resistant NPC and that targeting the SIRT2-FOXO3 axis may provide novel strategies for treating NPC and for overcoming chemoresistance.

Forkhead Domains of FOXO Transcription Factors Differ in both Overall Conformation and Dynamics

FOXO transcription factors regulate cellular homeostasis, longevity and response to stress. FOXO1 (also known as FKHR) is a key regulator of hepatic glucose production and lipid metabolism, and its specific inhibition may have beneficial effects on diabetic hyperglycemia by reducing hepatic glucose production. Moreover, all FOXO proteins are considered potential drug targets for drug resistance prevention in cancer therapy. However, the development of specific FOXO inhibitors requires a detailed understanding of structural differences between individual FOXO DNA-binding domains. The high-resolution structure of the DNA-binding domain of FOXO1 reported in this study and its comparison with structures of other FOXO proteins revealed differences in both their conformation and flexibility. These differences are encoded by variations in protein sequences and account for the distinct functions of FOXO proteins. In particular, the positions of the helices H1, H2 and H3, whose interface form the hydrophobic core of the Forkhead domain, and the interactions between hydrophobic residues located on the interface between the N-terminal segment, the H2-H3 loop, and the recognition helix H3 differ among apo FOXO1, FOXO3 and FOXO4 proteins. Therefore, the availability of apo structures of DNA-binding domains of all three major FOXO proteins will support the development of FOXO-type-specific inhibitors.

Dynamically decreased miR-671-5p expression is associated with oncogenic transformation and radiochemoresistance in breast cancer

Background

Understanding the molecular alterations associated with breast cancer (BC) progression may lead to more effective strategies for both prevention and management. The current model of BC progression suggests a linear, multistep process from normal epithelial to atypical ductal hyperplasia (ADH), to ductal carcinoma in situ (DCIS), and then invasive ductal carcinoma (IDC). Up to 20% ADH and 40% DCIS lesions progress to invasive BC if left untreated. Deciphering the molecular mechanisms during BC progression is therefore crucial to prevent over- or under-treatment. Our previous work demonstrated that miR-671-5p serves as a tumor suppressor by targeting Forkhead box protein M1 (FOXM1)-mediated epithelial-to-mesenchymal transition (EMT) in BC. Here, we aim to explore the role of miR-671-5p in the progression of BC oncogenic transformation and treatment.

Methods

The 21T series cell lines, which were originally derived from the same patient with metastatic BC, including normal epithelia (H16N2), ADH (21PT), primary DCIS (21NT), and cells derived from pleural effusion of lung metastasis (21MT), and human BC specimens were used. Microdissection, miRNA transfection, dual-luciferase, radio- and chemosensitivity, and host-cell reactivation (HCR) assays were performed.

Results

Expression of miR-671-5p displays a gradual dynamic decrease from ADH, to DCIS, and to IDC. Interestingly, the decreased expression of miR-671-5p detected in ADH coexisted with advanced lesions, such as DCIS and/or IDC (cADH), but not in simple ADH (sADH). Ectopic transfection of miR-671-5p significantly inhibited cell proliferation in 21NT (DCIS) and 21MT (IDC), but not in H16N2 (normal) and 21PT (ADH) cell lines. At the same time, the effect exhibited in time- and dose-dependent manner. Interestingly, miR-671-5p significantly suppressed invasion in 21PT, 21NT, and 21MT cell lines. Furthermore, miR-671-5p suppressed FOXM1-mediated EMT in all 21T cell lines. In addition, miR-671-5p sensitizes these cell lines to UV and chemotherapeutic exposure by reducing the DNA repair capability.

Conclusions

miR-671-5p displays a dynamic decrease expression during the oncogenic transition of BC by suppressing FOXM1-mediated EMT and DNA repair. Therefore, miR-671-5p may serve as a novel biomarker for early BC detection as well as a therapeutic target for BC management.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1173-5) contains supplementary material, which is available to authorized users.

EP300 and SIRT1/6 Co-Regulate Lapatinib Sensitivity Via Modulating FOXO3-Acetylation and Activity in Breast Cancer

Forkhead Box O3 (FOXO3) is a tumor suppressor whose activity is fine-tuned by post-translational modifications (PTMs). In this study, using the BT474 breast cancer cells and a recently established lapatinib resistant (BT474-Lap^R) cell line, we observed that higher FOXO3 and acetylated (Ac)-FOXO3 levels correlate with lapatinib sensitivity. Subsequent ectopic expression of EP300 led to an increase in acetylated-FOXO3 in sensitive but not in resistant cells. Drug sensitivity assays revealed that sensitive BT474 cells show increased lapatinib cytotoxicity upon over-expression of wild-type but not acetylation-deficient EP300. Moreover, FOXO3 recruitment to target gene promoters is associated with target gene expression and drug response in sensitive cells and the inability of FOXO3 to bind its target genes correlates with lapatinib-resistance in BT474-Lap^R cells. In addition, using SIRT1/6 specific siRNAs and chemical inhibitor, we also found that sirtuin 1 and -6 (SIRT1 and -6) play a part in fine-tuning FOXO3 acetylation and lapatinib sensitivity. Consistent with this, immunohistochemistry results from different breast cancer subtypes showed that high SIRT6/1 levels are associated with constitutive high FOXO3 expression which is related to FOXO3 deregulation/inactivation and poor prognosis in breast cancer patient samples. Collectively, our results suggest the involvement of FOXO3 acetylation in regulating lapatinib sensitivity of HER2-positive breast cancers.

HMGA1 promotes breast cancer angiogenesis supporting the stability, nuclear localization and transcriptional activity of FOXM1

Background

Breast cancer is the most common malignancy in women worldwide. Among the breast cancer subtypes, triple-negative breast cancer (TNBC) is the most aggressive and the most difficult to treat. One of the master regulators in TNBC progression is the architectural transcription factor HMGA1. This study aimed to further explore the HMGA1 molecular network to identify molecular mechanisms involved in TNBC progression.

Methods

RNA from the MDA-MB-231 cell line, silenced for HMGA1 expression, was sequenced and, with a bioinformatic analysis, molecular partners HMGA1 could cooperate with in regulating common downstream gene networks were identified. Among the putative partners, the FOXM1 transcription factor was selected. The relationship occurring between HMGA1 and FOXM1 was explored by qRT-PCR, co-immunoprecipitation and protein stability assays. Subsequently, the transcriptional activity of HMGA1 and FOXM1 was analysed by luciferase assay on the VEGFA promoter. The impact on angiogenesis was assessed in vitro, evaluating the tube formation ability of endothelial cells exposed to the conditioned medium of MDA-MB-231 cells silenced for HMGA1 and FOXM1 and in vivo injecting MDA-MB-231 cells, silenced for the two factors, in zebrafish larvae.

Results

Here, we discover FOXM1 as a novel molecular partner of HMGA1 in regulating a gene network implicated in several breast cancer hallmarks. HMGA1 forms a complex with FOXM1 and stabilizes it in the nucleus, increasing its transcriptional activity on common target genes, among them, VEGFA, the main inducer of angiogenesis. Furthermore, we demonstrate that HMGA1 and FOXM1 synergistically drive breast cancer cells to promote tumor angiogenesis both in vitro in endothelial cells and in vivo in a zebrafish xenograft model. Moreover, using a dataset of breast cancer patients we show that the co-expression of HMGA1, FOXM1 and VEGFA is a negative prognostic factor of distant metastasis-free survival and relapse-free survival.

Conclusions

This study reveals FOXM1 as a crucial interactor of HMGA1 and proves that their cooperative action supports breast cancer aggressiveness, by promoting tumor angiogenesis. Therefore, the possibility to target HMGA1/FOXM1 in combination should represent an attractive therapeutic option to counteract breast cancer angiogenesis.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1307-8) contains supplementary material, which is available to authorized users.

Regulation of PERK expression by FOXO3: a vulnerability of drug-resistant cancer cells

The major impediment to effective cancer therapy has been the development of drug resistance. The tumour suppressive transcription factor FOXO3 promotes cell cycle arrest, senescence and cell death, and mediates the cytotoxic and cytostatic functions of cancer therapeutics. In consequence, FOXO3 is often downregulated as an adaptive response in cancer and particularly in chemotherapeutic drug-resistant cells. Consistently, we find that FOXO3 expression is attenuated in the drug-resistant MCF-7-Epi^R and MCF-7-Tax^R compared to the parental MCF-7 breast cancer cells. Using ChIP, short-interfering RNA (siRNA) knockdown, and overexpression assays as well as Foxo^1/3/4-/- MEFs, we establish the endoplasmic reticulum (ER)-stress defence modulator PERK (eIF2AK3) as a direct downstream transcriptional target of FOXO3. In agreement, there is also a positive correlation between FOXO3 and PERK expression at the protein and RNA levels in breast cancer patient samples. We uncover that PERK expression is downregulated but its activity constitutively elevated in the drug-resistant cells. With this in mind, we exploit this adaptive response of low FOXO3 and PERK expression, and high PERK activity in drug-resistant breast cancer cells and show that these drug-resistant cells are specifically sensitive to PERK inhibition. In support of this finding, we show that ectopic overexpression of FOXO3 can reduce the sensitivity of the resistant cells to the PERK inhibitor GSK2606414, while the Foxo^1/3/4-/- MEFs expressing lower levels of PERK are more sensitive to PERK inhibition compared to wild-type MEFs. PERK inhibitor-titration and -time course experiments showed that the drug-resistant cells, which express lower expression and higher activity levels of PERK, are more sensitive to the increasing concentrations of PERK inhibitor compared to parental MCF-7 cells. Our present work thus reveals a chemotherapeutic drug-resistant cancer cell vulnerability in PERK and suggests PERK as a potential target for cancer therapy, specifically in the context of drug-resistant cancers.

Downregulation of FOXO3a by DNMT1 promotes breast cancer stem cell properties and tumorigenesis

Breast cancer stem cells (BCSCs) are tumor initiating cells that can self-renew and are highly tumorigenic and chemoresistant. Therefore, the identification of factors critical for BCSC function is vital for the development of therapies. Here, we report that DNMT1-mediated FOXO3a promoter hypermethylation leads to downregulation of FOXO3a expression in breast cancer. FOXO3a is functionally related to the inhibition of FOXM1/SOX2 signaling and to the consequent suppression of BCSCs properties and tumorigenicity. Moreover, we found that SOX2 directly transactivates DNMT1 expression and thereby alters the methylation landscape, which in turn feedback inhibits FOXO3a expression. Inhibition of DNMT activity suppressed tumor growth via regulation of FOXO3a/FOXM1/SOX2 signaling in breast cancer. Clinically, we observed a significant inverse correlation between FOXO3a and FOXM1/SOX2/DNMT1 expression levels, and loss of FOXO3a expression or increased expression of FOXM1, SOX2, and DNMT1 predicted poor prognosis in breast cancer. Collectively, our findings suggest an important role of the DNMT1/FOXO3a/FOXM1/SOX2 pathway in regulating BCSCs properties, suggesting potential therapeutic targets for breast cancer.

LINC01355 suppresses breast cancer growth through FOXO3-mediated transcriptional repression of CCND1

Previously, several protein-coding tumor suppressors localized at 1p36 have been reported. In the present work, we focus on functional long non-coding RNAs (lncRNAs) embedded in this locus. Small interfering RNA was used to identify lncRNA candidates with growth-suppressive activities in breast cancer. The mechanism involved was also explored. LINC01355 were downregulated in breast cancer cells relative to non-malignant breast epithelial cells. Overexpression of LINC01355 significantly inhibited proliferation, colony formation, and tumorigenesis of breast cancer cells. LINC01355 arrested breast cancer cells at the G0/G1 phase by repressing CCND1. Moreover, LINC01355 interacted with and stabilized FOXO3 protein, leading to transcriptional repression of CCND1. Importantly, LINC01355-mediated suppression of breast cancer growth was reversed by knockdown of FOXO3 or overexpression of CCND1. Clinically, LINC01355 was downregulated in breast cancer specimens and correlated with more aggressive features. There was a negative correlation between LINC01355 and CCND1 expression in breast cancer samples. LINC01355 acts as a tumor suppressor in breast cancer, which is ascribed to enhancement of FOXO3-mediated transcriptional repression of CCND1. Re-expression of LINC01355 may provide a potential therapeutic strategy to block breast cancer growth and progression.

The Role of Forkhead Box Proteins in Acute Myeloid Leukemia

Forkhead box (FOX) proteins are a group of transcriptional factors implicated in different cellular functions such as differentiation, proliferation and senescence. A growing number of studies have focused on the relationship between FOX proteins and cancers, particularly hematological neoplasms such as acute myeloid leukemia (AML). FOX proteins are widely involved in AML biology, including leukemogenesis, relapse and drug sensitivity. Here we explore the role of FOX transcription factors in the major AML entities, according to "The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia", and in the context of the most recurrent gene mutations identified in this heterogeneous disease. Moreover, we report the new evidences about the role of FOX proteins in drug sensitivity, mechanisms of chemoresistance, and possible targeting for personalized therapies.

Promyelocytic leukemia protein (PML) controls breast cancer cell proliferation by modulating Forkhead transcription factors

The multitasking promyelocytic leukemia (PML) protein was originally recognized as a tumor‐suppressive factor, but more recent evidence has implicated PML in tumor cell prosurvival actions and poor patient prognosis in specific cancer settings. Here, we report that inducible PMLIV expression inhibits cell proliferation as well as self‐renewal and impairs cell cycle progression of breast cancer cell lines in a reversible manner. Transcriptomic profiling identified a large number of PML‐deregulated genes associated with various cell processes. Among them, cell cycle‐ and division‐related genes and their cognitive regulators are highly ranked. In this study, we focused on previously unknown PML targets, namely the Forkhead transcription factors. PML suppresses the Forkhead box subclass M1 (FOXM1) transcription factor at both the RNA and protein levels, along with many of its gene targets. We show that FOXM1 interacts with PMLIV primarily via its DNA‐binding domain and dynamically colocalizes in PML nuclear bodies. In parallel, PML modulates the activity of Forkhead box O3 (FOXO3), a factor opposing certain FOXM1 activities, to promote cell survival and stress resistance. Thus, PMLIV affects the balance of FOXO3 and FOXM1 transcriptional programs by acting on discrete gene subsets to favor both growth inhibition and survival. Interestingly, PMLIV‐specific knockdown mimicked ectopic expression vis‐à‐vis loss of proliferative ability and self‐renewal, but also led to loss of survival ability as shown by increased apoptosis. We propose that divergent or similar effects on cell physiology may be elicited by high or low PMLIV levels dictated by other concurrent genetic or epigenetic cancer cell states that may additionally account for its disparate effects in various cancer types.