FOX(M1) news--it is cancer

Exosomes of Adipose-derived Stem Cells Conditioned Media Promotes Retinoblastoma and Forkhead-Box M1 Protein Expression

BACKGROUND: In the senescence process, the retinoblastoma (Rb) protein binds to E2F in hypophosphorylated conditions, preventing the cell to enter the S-phase in the cell cycle. Human Forkhead Box M1 (FOXM1) protein, key regulator G1/S and G2/M phases, decreases in the senescence process. Many studies have been carried out to reverse this system, one of which used exosomes of adipose-derived stem c ells conditioned media (ADSC-CM). These exosomes contain a variety of specific proteins which have pro-proliferation properties, however, little is known on the role of these exosomes toward the change of phosphorylated Rb and FOXM1. AIM: This study aims to find out the involvement of exosomes of ADSC-CM on these two proteins on senescence human dermal fibroblasts (HDFs). METHODS: In vitro experiment was undergone randomization sample and non-blinded pre-/post-test control group. The primary culture of senescent HDFs was transfected with exosomes of ADSC-CM; then, its effect on migration and senescence reversal was observed through analyzing Sa-β-gal, Rb, and FOXM1 protein expression. RESULTS: The expression of Sa-β-gal was higher in the control group. Our result demonstrated the exosome of ADSC-CM significantly induced the expression of Rb and FOXM1 protein in senescent HDFs (p < 0.05). CONCLUSION: It proved that exosomes of ADSC-CM could shift the senescent fibroblast into metabolically active cells.

FOXM1D potentiates PKM2-mediated tumor glycolysis and angiogenesis

Tumor growth, especially in the late stage, requires adequate nutrients and rich vasculature, in which PKM2 plays a convergent role. It has been reported that PKM2, together with FOXM1D, is upregulated in late-stage colorectal cancer and associated with metastasis; however, their underlying mechanism for promoting tumor progression remains elusive. Herein, we revealed that FOXM1D potentiates PKM2-mediated glycolysis and angiogenesis through multiple protein-protein interactions. In the presence of FBP, FOXM1D binds to tetrameric PKM2 and assembles a heterooctamer, restraining PKM2 metabolic activity by about a half and thereby promoting aerobic glycolysis. Furthermore, FOXM1D interacts with PKM2 and NF-κB and induces their nuclear translocation with the assistance of the nuclear transporter importin 4. Once in the nucleus, PKM2 and NF-κB complexes subsequently augment VEGFA transcription. The increased VEGFA is secreted extracellularly via exosomes, an event potentiated by the interaction of FOXM1 with VPS11, eventually promoting tumor angiogenesis. Based on these findings, our study provides another insight into the role of PKM2 in the regulation of glycolysis and angiogenesis.

Co-regulation and function of FOXM1/RHNO1 bidirectional genes in cancer

The FOXM1 transcription factor is an oncoprotein and a top biomarker of poor prognosis in human cancer. Overexpression and activation of FOXM1 is frequent in high-grade serous carcinoma (HGSC), the most common and lethal form of human ovarian cancer, and is linked to copy number gains at chromosome 12p13.33. We show that FOXM1 is co-amplified and co-expressed with RHNO1, a gene involved in the ATR-Chk1 signaling pathway that functions in the DNA replication stress response. We demonstrate that FOXM1 and RHNO1 are head-to-head (i.e., bidirectional) genes (BDG) regulated by a bidirectional promoter (BDP) (named F/R-BDP). FOXM1 and RHNO1 each promote oncogenic phenotypes in HGSC cells, including clonogenic growth, DNA homologous recombination repair, and poly-ADP ribosylase inhibitor resistance. FOXM1 and RHNO1 are one of the first examples of oncogenic BDG, and therapeutic targeting of FOXM1/RHNO1 BDG is a potential therapeutic approach for ovarian and other cancers.

WNT5a in Colorectal Cancer: Research Progress and Challenges

Despite the clinical development of new adjuvant and neoadjuvant chemotherapy drugs, colorectal cancer is still one of the leading causes of cancer-related death in human beings. WNT5a, an autocrine and paracrine β-catenin independent ligand, has been shown to induce tumor inhibition and carcinogenic signals, depending on the type of cancer. In patients with colorectal cancer, WNT5a triggers a variety of downstream signaling pathways, which mainly affect the migration and invasion of tumor cells. This article reviews the mechanism and therapeutic potential of WNT5a in colorectal cancer. In short, an in-depth understanding of the role of WNT5a in colorectal cancer is very helpful to better deal with this disease.

Identification of Redox-Sensitive Transcription Factors as Markers of Malignant Pleural Mesothelioma

Simple Summary

Malignant pleural mesothelioma is a lung tumor associated with asbestos exposure, with a poor prognosis, and a difficult pharmacological approach. Asbestos exposure is very toxic for the lungs, which counteract this toxic effect by activating some antioxidant defense proteins. When these proteins are more active that in normal conditions, as in several cancers, these tumors become able to survive and resist to stress or chemotherapy. In our laboratory, we collected cellular samples of mesothelioma and non-transformed mesothelium from Hospital’s Biobank and we evaluated these proteins. Our results demonstrated these proteins are upregulated in mesothelioma cells and not in non-transformed mesothelium. This event could be associated to toxic effects evoked by asbestos exposure, highlighting the need in the future to monitor asbestos-exposed people by measuring biomarkers identified, in the attempt to identify them as possible predictive markers and potential pharmacological targets addressed to improve mesothelioma prognosis.

Abstract

Although asbestos has been banned in most countries around the world, malignant pleural mesothelioma (MPM) is a current problem. MPM is an aggressive tumor with a poor prognosis, so it is crucial to identify new markers in the preventive field. Asbestos exposure induces oxidative stress and its carcinogenesis has been linked to a strong oxidative damage, event counteracted by antioxidant systems at the pulmonary level. The present study has been focused on some redox-sensitive transcription factors that regulate cellular antioxidant defense and are overexpressed in many tumors, such as Nrf2 (Nuclear factor erythroid 2-related factor 2), Ref-1 (Redox effector factor 1), and FOXM1 (Forkhead box protein M1). The research was performed in human mesothelial and MPM cells. Our results have clearly demonstrated an overexpression of Nrf2, Ref-1, and FOXM1 in mesothelioma towards mesothelium, and a consequent activation of downstream genes controlled by these factors, which in turn regulates antioxidant defense. This event is mediated by oxidative free radicals produced when mesothelial cells are exposed to asbestos fibers. We observed an increased expression of Nrf2, Ref-1, and FOXM1 towards untreated cells, confirming asbestos as the mediator of oxidative stress evoked at the mesothelium level. These factors can therefore be considered predictive biomarkers of MPM and potential pharmacological targets in the treatment of this aggressive cancer.

FOXM1 Inhibition in Ovarian Cancer Tissue Cultures Affects Individual Treatment Susceptibility Ex Vivo

Simple Summary

Late diagnosis of ovarian cancer is a major reason for the high mortality rate of this tumor entity. The time to determine tumor susceptibility to treatment is scarce and resistance to therapy occurs very frequently. Here, we aim for a model system that can determine tumor response to (I) study novel drugs and (II) enhance patient stratification. Tissue specimens (n = 10) were acquired from fresh surgical samples. Tissue cultures were cultivated and treated with clinically relevant therapeutics and an FOXM1 inhibitor for 3–6 days. The transcription factor FOXM1 is a key regulator of tumor survival affecting multiple cancerogenic target genes. Gene expression of FOXM1 and its targets BRCA1/2 and RAD51 were investigated together with tumor susceptibility. Tissue cultures successfully demonstrated the individual benefit of FOXM1 inhibition and revealed the potency of the complex model system for oncological research.

Abstract

Diagnosis in an advanced state is a major hallmark of ovarian cancer and recurrence after first line treatment is common. With upcoming novel therapies, tumor markers that support patient stratification are urgently needed to prevent ineffective therapy. Therefore, the transcription factor FOXM1 is a promising target in ovarian cancer as it is frequently overexpressed and associated with poor prognosis. In this study, fresh tissue specimens of 10 ovarian cancers were collected to investigate tissue cultures in their ability to predict individual treatment susceptibility and to identify the benefit of FOXM1 inhibition. FOXM1 inhibition was induced by thiostrepton (3 µM). Carboplatin (0.2, 2 and 20 µM) and olaparib (10 µM) were applied and tumor susceptibility was analyzed by tumor cell proliferation and apoptosis in immunofluorescence microscopy. Resistance mechanisms were investigated by determining the gene expression of FOXM1 and its targets BRCA1/2 and RAD51. Ovarian cancer tissue was successfully maintained for up to 14 days ex vivo, preserving morphological characteristics of the native specimen. Thiostrepton downregulated FOXM1 expression in tissue culture. Individual responses were observed after combined treatment with carboplatin or olaparib. Thus, we successfully implemented a complex tissue culture model to ovarian cancer and showed potential benefit of combined FOXM1 inhibition.

FOXM1 and Cancer: Faulty Cellular Signaling Derails Homeostasis

Forkhead box transcription factor, FOXM1 is implicated in several cellular processes such as proliferation, cell cycle progression, cell differentiation, DNA damage repair, tissue homeostasis, angiogenesis, apoptosis, and redox signaling. In addition to being a boon for the normal functioning of a cell, FOXM1 turns out to be a bane by manifesting in several disease scenarios including cancer. It has been given an oncogenic status based on several evidences indicating its role in tumor development and progression. FOXM1 is highly expressed in several cancers and has also been implicated in poor prognosis. A comprehensive understanding of various aspects of this molecule has revealed its role in angiogenesis, invasion, migration, self- renewal and drug resistance. In this review, we attempt to understand various mechanisms underlying FOXM1 gene and protein regulation in cancer including the different signaling pathways, post-transcriptional and post-translational modifications. Identifying crucial molecules associated with these processes can aid in the development of potential pharmacological approaches to curb FOXM1 mediated tumorigenesis.

Propofol suppresses lung cancer tumorigenesis by modulating the circ-ERBB2/miR-7-5p/FOXM1 axis

BACKGROUND

Propofol is a commonly used anesthetic for cancer surgery. Previous studies have shown that propofol has an anticancer role in various cancers, including lung cancer. This study aimed to investigate the role of propofol in lung cancer and its underlying mechanism.

METHODS

Cell proliferation was determined by cell counting kit-8 (CCK-8) and colony formation assays. Flow cytometry and transwell assays were used to detect cell apoptosis and invasion, respectively. Glycolysis was evaluated by detecting glucose consumption, lactate production and ATP/ADP ratios. The levels of circular RNA erb-b2 receptor tyrosine kinase 2 (circ-ERBB2), microRNA-7-5p (miR-7-5p) and forkhead box M1 (FOXM1) were tested by quantitative real-time PCR and Western blot. The binding relationship between miR-7-5p and circ-ERBB2/FOXM1 was verified by dual-luciferase reporter assay. Moreover, in vivo experiments were performed by establishing a mouse xenograft model.

RESULTS

Propofol suppressed cell proliferation, invasion and glycolysis and expedited apoptosis in lung cancer cells. Circ-ERBB2 and FOXM1 were upregulated, while miR-7-5p was decreased in lung cancer tissues and cells. Propofol suppressed lung cancer cell progression by regulating circ-ERBB2. Additionally, miR-7-5p directly interacted with circ-ERBB2 and FOXM1. Also, propofol played an antitumor role in lung cancer via modulating miR-7-5p or FOXM1. Moreover, circ-ERBB2 knockdown enhanced the suppressive effect of propofol on tumor growth in vivo.

CONCLUSIONS

Propofol inhibited lung cancer progression via mediating circ-ERBB2/miR-7-5p/FOXM1 axis, which might provide an effective therapeutic target for lung cancer therapy.

High glucose upregulates FOXM1 expression via EGFR/STAT3 dependent activation to promote progression of cholangiocarcinoma

AIMS

Epidemiological studies indicate diabetes mellitus and hyperglycemia as risk factors of cancers including cholangiocarcinoma (CCA). How high glucose promotes cancer development and progression, however, is still unrevealed. In this study, insight into the molecular pathway of high glucose promoting progression of CCA cells was investigated.

MAIN METHODS

Human CCA cell lines, KKU-213A and KKU-213B were cultured in normal glucose (NG; 5.56 mM) or high glucose (HG; 25 mM) and used as NG and HG cells. Forkhead box M1 (FOXM1) expression was transiently suppressed using siFOXM1. Western blotting and image analysis were employed to semi-quantitatively determine the expression levels of the specified proteins. The migration and invasion of CCA cells were revealed using Boyden chamber assays.

KEY FINDINGS

All HG cells exhibited higher expression of FOXM1 than the corresponding NG cells in a dose dependent manner. Suppression of FOXM1 expression by siFOXM1 significantly reduced migration and invasion abilities of CCA cells by suppression of Slug and MMP2 expression. Inhibition of STAT3 activation using Stattic, significantly suppressed expression of FOXM1 and Slug and decreased migration and invasion abilities of HG cells. In addition, EGFR expression was significantly higher in HG cells than NG cells and increased dependently with glucose concentration. Inhibition of EGFR activation by cetuximab significantly suppressed STAT3 activation and FOXM1 expression.

SIGNIFICANCE

The mechanism of high glucose promoting progression of CCA cells was revealed to be via in part by upregulation of FOXM1 expression under EGF/EGFR and STAT3 dependent activation.

The Role of Forkhead Box Family in Bone Metabolism and Diseases

Forkhead box (Fox) family, an evolutionarily conserved family of transcription factors carrying the "Forkhead" motif, plays an indispensable role in human health and disease. Fox family genes are involved in cell differentiation, proliferation and apoptosis, embryonic development, aging, glucose and lipid metabolism, and immune regulation. The regulatory role of the Fox family in the context of bone metabolism and orthopedic diseases is an emerging research hotspot. In this review, we highlight the major molecular mechanisms underlying the regulatory role of Fox factors in bone metabolism, bone development, bone homeostasis, and bone diseases associated with inhibition or upregulation of Fox factors. In addition, we discuss the emerging evidence in the realm of Fox factor-based therapeutics.

Transcription factors in colorectal cancer: molecular mechanism and therapeutic implications

Colorectal cancer (CRC) is a major cause of cancer mortality worldwide, however, the molecular mechanisms underlying the pathogenesis of CRC remain largely unclear. Recent studies have revealed crucial roles of transcription factors in CRC development. Transcription factors essential for the regulation of gene expression by interacting with transcription corepressor/enhancer complexes and they orchestrate downstream signal transduction. Deregulation of transcription factors is a frequent occurrence in CRC, and the accompanying drastic changes in gene expression profiles play fundamental roles in multistep process of tumorigenesis, from cellular transformation, disease progression to metastatic disease. Herein, we summarized current and emerging key transcription factors that participate in CRC tumorigenesis, and highlighted their oncogenic or tumor suppressive functions. Moreover, we presented critical transcription factors of CRC, emphasized the major molecular mechanisms underlying their effect on signal cascades associated with tumorigenesis, and summarized of their potential as molecular biomarkers for CRC prognosis therapeutic response, as well as drug targets for CRC treatment. A better understanding of transcription factors involved in the development of CRC will provide new insights into the pathological mechanisms and reveal novel prognostic biomarkers and therapeutic strategies for CRC.

FOXM1/DVL2/Snail axis drives metastasis and chemoresistance of colorectal cancer

Colorectal cancer (CRC) is the third most common type of cancer worldwide. Metastasis and chemoresistance are regarded as the two leading causes of treatment failure and high mortality in CRC. Forkhead Box M1 (FOXM1) has been involved in malignant behaviors of cancer. However, the role and mechanism of FOXM1 in simultaneously regulating metastasis and chemoresistance of CRC remain poorly understood. Here, we found that FOXM1 was overexpressed in oxaliplatin- and vincristine-resistant CRC cells (HCT-8/L-OHP and HCT-8/VCR) with enhanced metastatic potential, compared with HCT-8 cells. FOXM1 overexpression increased migration, invasion and drug-resistance to oxaliplatin and vincristine in HCT-8 cells, while FOXM1 knockdown using shFOXM1 impaired metastasis and drug-resistance in HCT-8/L-OHP and HCT-8/VCR cells. Moreover, FOXM1 up-regulated Snail to trigger epithelial-mesenchymal transition-like molecular changes and multidrug-resistance protein P-gp expression, while silencing Snail inhibited FOXM1-induced metastasis and drug-resistance. We further identified that disheveled-2 (DVL2) was crucial for FOXM1-induced Snail expression, metastasis and chemoresistance. Furthermore, FOXM1 bound to DVL2, and enhanced nuclear translocation of DVL2 and DVL2-mediated transcriptional activity of Wnt/β-catenin known to induce Snail expression. In conclusion, FOXM1/DVL2/Snail axis triggered aggressiveness of CRC. Blocking FOXM1/DVL2/Snail pathway simultaneously inhibited metastasis and chemoresistance in CRC cells, providing a new strategy for successful CRC treatment.

Thiostrepton and miR-216b synergistically promote osteosarcoma cell cytotoxicity and apoptosis by targeting FoxM1

Osteosarcoma is a common primary bone cancer that there are currently no effective treatment strategies for. Forkhead box M1 (FoxM1) is key in the development of osteosarcoma, and microRNA (miR)-216b serves an antitumor role by targeting FoxM1. Moreover, thiostrepton (TST), a natural thiazole antibiotic, induces antitumor effects and specifically targets FoxM1. Therefore, the present study investigated whether thiostrepton and miR-216b synergistically inhibited osteosarcoma cells by targeting FoxM1. The MTT assay, reverse transcription-quantitative PCR, a dual-luciferase reporter assay and flow cytometry were performed. Compared with the human osteoblast cell line hFOB1.19, miR-216b expression was significantly downregulated in the osteosarcoma cell lines U2OS, MG63 and Saos-2. By contrast, FoxM1 expression was significantly upregulated in osteosarcoma cell lines compared with the hFOB1.19 cell line. The results indicated that miR-216b targeted the 3′-untranslated region of FoxM1. Moreover, the results suggested that miR-216b cooperated with TST to decrease cell cytotoxicity and increase cell apoptosis. In addition, miR-216b cooperated with TST to increase Bax expression and decrease Bcl-2 expression. In conclusion, the combination of TST and miR-216b synergistically promoted osteosarcoma cell cytotoxicity and apoptosis by targeting FoxM1. Therefore, the present study suggested that the combination of TST and miR-216b may serve as a promising therapeutic strategy for osteosarcoma.

Transcriptional landscape of cholangiocarcinoma revealed by weighted gene coexpression network analysis

Cholangiocarcinoma (CCA) is a type of cancer with limited treatment options and a poor prognosis. Although some important genes and pathways associated with CCA have been identified, the relationship between coexpression and phenotype in CCA at the systems level remains unclear. In this study, the relationships underlying the molecular and clinical characteristics of CCA were investigated by employing weighted gene coexpression network analysis (WGCNA). The gene expression profiles and clinical features of 36 patients with CCA were analyzed to identify differentially expressed genes (DEGs). Subsequently, the coexpression of DEGs was determined by using the WGCNA method to investigate the correlations between pairs of genes. Network modules that were significantly correlated with clinical traits were identified. In total, 1478 mRNAs were found to be aberrantly expressed in CCA. Seven coexpression modules that significantly correlated with clinical characteristics were identified and assigned representative colors. Among the 7 modules, the green and blue modules were significantly related to tumor differentiation. Seventy-eight hub genes that were correlated with tumor differentiation were found in the green and blue modules. Survival analysis showed that 17 hub genes were prognostic biomarkers for CCA patients. In addition, we found five new targets (ISM1, SULT1B1, KIFC1, AURKB and CCNB1) that have not been studied in the context of CCA and verified their differential expression in CCA through experiments. Our results not only promote our understanding of the relationship between the transcriptome and clinical data in CCA but will also guide the development of targeted molecular therapy for CCA.

Loss of aryl hydrocarbon receptor potentiates FoxM1 signaling to enhance self-renewal of colonic stem and progenitor cells

The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that senses xenobiotics, diet, and gut microbial-derived metabolites, is increasingly recognized as a key regulator of intestinal biology. However, its effects on the function of colonic stem and progenitor cells remain largely unexplored. Here, we observed that inducible deletion of AhR in Lgr5⁺ stem cells increases the percentage of colonic stem cells and enhances organoid initiating capacity and growth of sorted stem and progenitor cells, while AhR activation has the opposite effect. Moreover, intestinal-specific AhR knockout increases basal stem cell and crypt injury-induced cell proliferation and promotes colon tumorigenesis in a preclinical colitis-associated tumor model by upregulating FoxM1 signaling. Mechanistically, AhR transcriptionally suppresses FoxM1 expression. Activation of AhR in human organoids recapitulates phenotypes observed in mice, such as reduction in the percentage of colonic stem cells, promotion of stem cell differentiation, and attenuation of FoxM1 signaling. These findings indicate that the AhR-FoxM1 axis, at least in part, mediates colonic stem/progenitor cell behavior.

Cediranib, an inhibitor of vascular endothelial growth factor receptor kinases, inhibits proliferation and invasion of prostate adenocarcinoma cells

Prostate Cancer is the second cause of cancer-related death in men and development of metastatic castration-resistant prostate cancer (mCRPC) is the major reason for its high mortality rate. Despite various treatments, all patients succumb to resistant disease, suggesting that there is a pressing need for novel and more efficacious treatments. Members of the vascular endothelial growth factor (VEGF) family play key roles in the tumorigenesis of mCRPC, indicating that VEGF-targeted therapies may have potential anti-tumor efficacy in this malignancy. However, due to compensatory activation of other family members, clinical trials with single-targeted VEGF inhibitors were discouraging. Here, we determined the anti-neoplastic activity of Cediranib, a pan-VEGF receptor inhibitor, in the mCRPC cell lines. Anti-growth effects of Cediranib were studied by MTT and BrdU cell proliferation assays and crystal violet staining. Annexin V/PI, radiation therapy and cell motility assays were carried out to examine the effects of Cediranib on apoptosis, radio-sensitivity and cell motility. Quantitative reverse transcription-PCR (qRT-PCR) and Western blot analyses were conducted to determine the molecular mechanisms underlying the anti-tumor activity of Cediranib. Cediranib decreased cell viability and induced apoptosis via inhibition of the anti-apoptotic proteins. Combination with Cediranib synergistically increased Docetaxel sensitivity and potentiated the effects of radiation therapy. Furthermore, Cediranib impaired cell motility via decrease in the expression of the epithelial-to-mesenchymal transition markers. These findings suggest that Cediranib may have anti-tumor activity in mCRPC cells and warrant further investigation on the therapeutic activity of this pan-VEGF receptor inhibitor in mCRPC.

Introduction to Thiopeptides: Biological Activity, Biosynthesis, and Strategies for Functional Reprogramming

Thiopeptides (also known as thiazolyl peptides) are structurally complex natural products with rich biological activities. Known for over 70 years for potent killing of Gram-positive bacteria, thiopeptides are experiencing a resurgence of interest in the last decade, primarily brought about by the genomic revolution of the 21st century. Every area of thiopeptide research-from elucidating their biological function and biosynthesis to expanding their structural diversity through genome mining-has made great strides in recent years. These advances lay the foundation for and inspire novel strategies for thiopeptide engineering. Accordingly, a number of diverse approaches are being actively pursued in the hope of developing the next generation of natural-product-inspired therapeutics. Here, we review the contemporary understanding of thiopeptide biological activities, biosynthetic pathways, and approaches to structural and functional reprogramming, with a special focus on the latter.

Comprehensive expression analysis of mRNA and microRNA for the investigation of compensatory mechanisms in the rat kidney after unilateral nephrectomy

Compensation is a physiological response that occurs during chemical exposure to maintain homeostasis. Because compensatory responses are not usually considered adverse effects, it is important to understand compensatory mechanisms for chemical risk assessment. Although the kidney is a major target organ for toxicity, there is controversy over whether hyperplasia or hypertrophy contributes to the compensatory mechanism, and there is limited information to apply for chemical risk assessment. In the present study, compensatory mechanisms of the kidney were investigated in a unilateral nephrectomy (UNx) model using adult male and female F344 rats. In residual kidneys of male and female rats after UNx, 5-bromo-2'-deoxyuridine-labeling indices and mRNA expression of cell cycle-related genes were increased, although there were no fluctuations in mRNA expression of transforming growth factor-β1, which contributes to hypertrophy in renal tubules. Pathway analysis using mRNA expression data from a complementary DNA (cDNA) microarray revealed that canonical pathways related to cell proliferation were mainly activated and that forkhead box M1 (FOXM1) was an upstream regulator of compensatory cell proliferation in residual kidneys of male and female rats. cDNA microarray for microRNAs (miRNAs) demonstrated that nine miRNAs were downregulated in residual kidneys, and mRNA/miRNA integrated analysis indicated that miRNAs were associated with the expression of factors downstream of FOXM1. Overall, these results suggested that FOXM1-mediated hyperplasia rather than hypertrophy contributed to compensatory mechanisms in the kidney and that miRNAs regulated downstream FOXM1 signaling. These results will be beneficial for evaluating nephrotoxicity in chemical risk assessment and for developing new biomarkers to predict nephrotoxicity.

Recent progress on the role and molecular mechanism of chicken ovalbumin upstream promoter-transcription factor II in cancer

Chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII) is an orphan receptor that regulates the expression of genes involved in development and homeostasis. COUP-TFII is also dysregulated in cancer, where it plays important roles in oncogenesis and malignant progression. Recent studies have also investigated altered microRNA-mediated regulation of COUP-TFII in cancer. Although many investigators have studied the expression and clinical significance of COUP-TFII in several cancer types, there remain many controversies regarding its role in these diseases. In this review, we will describe the functions and underlying molecular mechanisms of COUP-TFII in several cancers, especially colorectal, gastric, breast, and prostate cancer; additionally, we will briefly summarize what is known about microRNA-mediated regulation of COUP-TFII.

WHSC1 promotes wnt/β-catenin signaling in a FoxM1-dependent manner facilitating proliferation, invasion and epithelial-mesenchymal transition in breast cancer

Objectives: Wolf-Hirschhorn syndrome candidate gene-1 (WHSC1) is highly expressed in various malignant tumors. We investigated the correlation and regulatory pathway of WHSC1 in the progression of breast cancer (BC).Methods: The expression and distribution of WHSC1 in the BC tissues and cell lines were determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunohistochemical staining. Spearman correlation analysis demonstrated the correlation between WHSC1 high expression level and the clinical characteristics of BC patients. The effects of WHSC1 on the proliferation, apoptosis, migration and invasion of BC cells were analyzed by cell transfection, MTT, colony formation, scratch assay, and transwell. Furthermore, the expression of Forkhead box M1 (FoxM1) and the location of β-catenin were detected by qRT-PCR and western blot.Results: Firstly, WHSC1 expression was up-regulated in BC tissues and cell lines. The high expression of WHSC1 in BC is associated with the tumor size (p = 0.027), metastasis (p = 0.018) and pathological stages (p = 0.025) of the BC patients. The knockdown of WHSC1 inhibited the growth, proliferation migration, invasion and EMT of BC cell lines. Furthermore, WHSC1 could promote the expression of FoxM1 in BC cells and tissues. WHSC1 enhanced the expression of FoxM1, and promoted the nuclear localization of β-catenin, and thus activated the downstream genes expression of Wnt/β-catenin signaling pathway to regulate the development of BC.Conclusion: In summary, our study elucidates the correlation and specific regulatory mechanism between WHSC1 and the progression of BC, thus implying that WHSC1 may function as molecular diagnosis, prognosis and molecular targeted therapy of BC.

Genomics and molecular mechanisms of high grade serous ovarian cancer: the 12th Biennial Rivkin Center Ovarian Cancer Research Symposium

OBJECTIVE

The aim of this study was to review current research efforts in genomics and molecular mechanisms of high grade serous ovarian cancer, presented at the 12th Biennial Rivkin Center Ovarian Cancer Research Symposium, held at the University of Washington.

METHODS

The 12th Biennial Rivkin Center Ovarian Cancer Research Symposium brought together leaders in the field to discuss recent advances in ovarian cancer research and therapy.

RESULTS

The genomics and molecular mechanisms of ovarian cancer session featured invited speaker presentations by Dr Alan D' Andrea on 'Deoxyribonucleic acid (DNA) repair in ovarian cancer' and Dr Kathleen Cho on 'Modeling the genomics of high grade serous carcinoma in the mouse'. Eight additional oral presentations and 46 poster presentations were selected from the submitted abstracts that highlighted current research efforts in p53, DNA repair, genomic instability and modeling disease in mice, and organoids in high grade serous ovarian cancer.

CONCLUSIONS

New technologies utilizing clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 (CAS9) approaches in mice, organoids, and cell based screens continue to advance our knowledge of key molecular drivers of ovarian cancer initiation, progression, and drug resistance. Improved understanding of the mechanisms of poly ADP ribose polymerase inhibitor resistance may lead to new therapeutic strategies to enhance outcomes in women with high grade serous ovarian cancer.

FOXM1 Deubiquitination by USP21 Regulates Cell Cycle Progression and Paclitaxel Sensitivity in Basal-like Breast Cancer

The transcription factor FOXM1 contributes to cell cycle progression and is significantly upregulated in basal-like breast cancer (BLBC). Despite its importance in normal and cancer cell cycles, we lack a complete understanding of mechanisms that regulate FOXM1. We identified USP21 in an RNAi-based screen for deubiquitinases that control FOXM1 abundance. USP21 increases the stability of FOXM1, and USP21 binds and deubiquitinates FOXM1 in vivo and in vitro, indicating a direct enzyme-substrate relationship. Depleting USP21 downregulates the FOXM1 transcriptional network and causes a signifi-cant delay in cell cycle progression. Significantly, USP21 depletion sensitized BLBC cell lines and mouse xenograft tumors to paclitaxel, an anti-mitotic, frontline therapy in BLBC treatment. USP21 is the most frequently amplified deubiquitinase in BLBC patient tumors, and its amplification co-occurs with the upregulation of FOXM1 protein. Altogether, these data suggest a role for USP21 in the proliferation and potentially treatment of FOXM1-high, USP21-high BLBC.

The cell cycle transcription factor FOXM1 is activated in basal-like breast cancer (BLBC) and associated with therapeutic resistance and poor patient outcomes. Arceci et al. show USP21 antagonizes FOXM1 degradation, thereby promoting proliferation and paclitaxel resistance. USP21 is catalytically active and recurrently overexpressed in BLBC, representing a potential therapeutic target.

Forkhead box M1 transcription factor: a novel target for pulmonary arterial hypertension therapy

BACKGROUND

Forkhead box M1 (FoxM1), a member of forkhead family, plays a key role in carcinogenesis, progression, invasion, metastasis and drug resistance. Based on the similarities between cancer and pulmonary arterial hypertension, studies on the roles and mechanisms of FoxM1 in pulmonary arterial hypertension have been increasing. This article aims to review recent advances in the mechanisms of signal transduction associated with FoxM1 in pulmonary arterial hypertension.

DATA SOURCES

Articles were retrieved from PubMed and MEDLINE published after 1990, including-but not limited to-FoxM1 and pulmonary arterial hypertension.

RESULTS

FoxM1 is overexpressed in pulmonary artery smooth muscle cells in both pulmonary arterial hypertension patients and animal models, and promotes pulmonary artery smooth muscle cell proliferation and inhibits cell apoptosis via regulating cell cycle progression. Multiple signaling molecules and pathways, including hypoxia-inducible factors, transforming growth factor-β/Smad, SET domain-containing 3/vascular endothelial growth factor, survivin, cell cycle regulatory genes and DNA damage response network, are reported to cross talk with FoxM1 in pulmonary arterial hypertension. Proteasome inhibitors are effective in the prevention and treatment of pulmonary arterial hypertension by inhibiting the expression and transcriptional activity of FoxM1.

CONCLUSIONS

FoxM1 has a crucial role in the pathogenesis of pulmonary arterial hypertension and may represent a novel therapeutic target. But more details of interaction between FoxM1 and other signaling pathways need to be clarified in the future.

FOXM1: a potential therapeutic target in human solid cancers

Introduction: FOXM1 is one of the most frequently overexpressed proteins in human solid cancers. Here, we discuss novel direct targets of FOXM1 as well as new pathways involving FOXM1, through which this protein exerts its oncogenic activity.Areas covered: We give a detailed review of FOXM1 transcriptional targets involved in 16 different types of human cancer as published in the literature in the last 5 years. We also discuss a novel positive feedback loop between FOXM1 and AKT - both well-established master regulators of cancer.Expert opinion: Despite the discovery of several FOXM1 inhibitors over the years (by our team and others), their therapeutic use is limited by their adverse off-target effects.Newly-discovered proteins regulated by FOXM1 present a promising alternative approach to target its pro-cancer activity. In addition, targeting regulating proteins that take part in the positive feedback loop between FOXM1/AKT has the double advantage of suppressing both, and can lead to developing novel anti-cancer drugs.

High expression of FOXM1 critical for sustaining cell proliferation in mitochondrial DNA-less liver cancer cells

The copy number of mitochondrial DNA (mtDNA) is decreased in most cancer types, including hepatocellular carcinoma (HCC), compared to normal counterparts. However, a decrease in mtDNA usually leads to defects in cell proliferation, which contradicts the robustness of cancer cell proliferation. In this study, we found that four out of seven HCC cell lines were of the mtDNA-less type. Interestingly, FOXM1, a member of the FOX transcription factor family, was highly expressed in a subset of them with proliferative potential maintained. B-MYB, a partner of FOXM1, was also expressed in the same cell lines. RNAi-mediated experiments demonstrated that when FOXM1/B-MYB was silenced in the cell lines, cell cycle-related genes were downregulated, while p21^Cip1 was induced with senescence-associated β-galactosidase, resulting in G₁/S cell cycle arrest. These results suggest that high expression of FOXM1/B-MYB is critical for sustaining cell proliferation in mtDNA-less cells. In addition, we found that high expression of FOXM1 was mediated by the deubiquitinating enzyme, OTUB1, in one cell line. Thus, interference with FOXM1/B-MYB expression, such as through OTUB1 inhibition, may induce a dormant state of senescence-like proliferation arrest in mtDNA-less cancer cells. This finding may be utilized for the development of precision medicine for relevant cancers.

Bortezomib inhibits growth and sensitizes glioma to temozolomide (TMZ) via down-regulating the FOXM1-Survivin axis

Background

High-grade glioma (HGG) is a fatal human cancer. Bortezomib, a proteasome inhibitor, has been approved for the treatment of multiple myeloma but its use in glioma awaits further investigation. This study aimed to explore the chemotherapeutic effect and the underlying mechanism of bortezomib on gliomas.

Methods

U251 and U87 cell viability and proliferation were detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, tumor cell spheroid growth, and colony formation assay. Cell apoptosis and cell cycle were detected by flow cytometry. Temozolomide (TMZ)-insensitive cell lines were induced by long-term TMZ treatment, and cells with stem cell characteristics were enriched with stem cell culture medium. The mRNA levels of interested genes were measured via reverse transcription-quantitative polymerase chain reaction, and protein levels were determined via Western blotting/immunofluorescent staining in cell lines and immunohistochemical staining in paraffin-embedded sections. Via inoculating U87 cells subcutaneously, glioma xenograft models in nude mice were established for drug experiments. Patient survival data were analyzed using the Kaplan–Meier method.

Results

Bortezomib inhibited the viability and proliferation of U251 and U87 cells in a dose- and time-dependent manner by inducing apoptosis and cell cycle arrest. Bortezomib also significantly inhibited the spheroid growth, colony formation, and stem-like cell proliferation of U251 and U87 cells. When administrated in combination, bortezomib showed synergistic effect with TMZ in vitro and sensitized glioma to TMZ treatment both in vitro and in vivo. Bortezomib reduced both the mRNA and protein levels of Forkhead Box M1 (FOXM1) and its target gene Survivin. The FOXM1–Survivin axis was markedly up-regulated in established TMZ-insensitive glioma cell lines and HGG patients. Expression levels of FOXM1 and Survivin were positively correlated with each other and both related to poor prognosis in glioma patients.

Conclusions

Bortezomib was found to inhibit glioma growth and improved TMZ chemotherapy efficacy, probably via down-regulating the FOXM1–Survivin axis. Bortezomib might be a promising agent for treating malignant glioma, alone or in combination with TMZ.

Identification of key genes and evaluation of clinical outcomes in lung squamous cell carcinoma using integrated bioinformatics analysis

Lung cancer is the leading cause of cancer-related mortality worldwide. Despite progress in the treatment of non-small-cell lung cancer, there are limited treatment options for lung squamous cell carcinoma (LUSC), compared with lung adenocarcinoma. The present study investigated the disease mechanism of LUSC in order to identify key candidate genes for diagnosis and therapy. A total of three gene expression profiles (GSE19188, GSE21933 and GSE74706) were analyzed using GEO2R to identify common differentially expressed genes (DEGs). The DEGs were then investigated using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. A protein-protein interaction (PPI) network was constructed via the Search Tool for the Retrieval of Interacting Genes/Proteins, and visualized using Cytoscape software. The expression levels of the hub genes identified using CytoHubba were validated using the University of California, Santa Cruz (UCSC) database and the Human Protein Atlas. A Kaplan-Meier curve and Gene Expression Profiling Interactive Analysis were then employed to evaluate the associated prognosis and clinical pathological stage of the hub genes. Furthermore, non-coding RNA regulatory networks were constructed using the Gene-Cloud Biotechnology information website. A total of 359 common DEGs (155 upregulated and 204 downregulated) were identified, which were predominantly enriched in 'mitotic nuclear division', 'cell division', 'cell cycle' and 'p53 signaling pathway'. The PPI network consisted of 257 nodes and 2,772 edges, and the most significant module consisted of 66 upregulated genes. A total of 19 hub genes exhibited elevated RNA levels, and 10 hub genes had elevated protein levels compared with normal lung tissues. The upregulation of five hub genes (CCNB1, CEP55, FOXM1, MKI67 and TYMS; defined in Table I) were significantly associated with poor overall survival and unfavorable clinical pathological stages. Various ncRNAs, such as C1orf220, LINC01561 and MGC39584, may also play important roles in hub-gene regulation. In conclusion, the present study provides further understanding of the pathogenesis of LUSC, and reveals CCNB1, CEP55, FOXM1, MKI67 and TYMS as potential biomarkers or therapeutic targets.

Endothelial and Smooth Muscle Cell Interaction via FoxM1 Signaling Mediates Vascular Remodeling and Pulmonary Hypertension

RATIONALE

Angioproliferative vasculopathy is a hallmark of pulmonary arterial hypertension (PAH). However, little is known about how endothelial cell (EC) and smooth muscle cell (SMC) crosstalk regulates the angioproliferative vascular remodeling.

OBJECTIVES

To investigate the role of EC and SMC interaction and underlying signaling pathways in pulmonary hypertension (PH) development.

METHODS

SMC-specific Foxm1 (forkhead box M1) or Cxcr4 knockout mice, EC-specific Foxm1 or Egln1 knockout mice, and EC-specific Egln1/Cxcl12 double knockout mice were used to assess the role of FoxM1 on SMC proliferation and PH. Lung tissues and cells from patients with PAH were used to validate clinical relevance. FoxM1 inhibitor thiostrepton was used in Sugen 5416/hypoxia- and monocrotaline-challenged rats.

MEASUREMENTS AND MAIN RESULTS

FoxM1 expression was markedly upregulated in lungs and pulmonary arterial SMCs of patients with idiopathic PAH and four discrete PH rodent models. Mice with SMC- (but not EC-) specific deletion of Foxm1 were protected from hypoxia- or Sugen 5416/hypoxia-induced PH. The upregulation of FoxM1 in SMCs induced by multiple EC-derived factors (PDGF-B, CXCL12, ET-1, and MIF) mediated SMC proliferation. Genetic deletion of endothelial Cxcl12 in Egln1^Tie2Cre mice or loss of its cognate receptor Cxcr4 in SMCs in hypoxia-treated mice inhibited FoxM1 expression, SMC proliferation, and PH. Accordingly, pharmacologic inhibition of FoxM1 inhibited severe PH in both Sugen 5416/hypoxia and monocrotaline-challenged rats.

CONCLUSIONS

Multiple factors derived from dysfunctional ECs induced FoxM1 expression in SMCs and activated FoxM1-dependent SMC proliferation, which contributes to pulmonary vascular remodeling and PH. Thus, targeting FoxM1 signaling represents a novel strategy for treatment of idiopathic PAH.

[YAP induces chromosomal instability in liver cancer patients]

BACKGROUND

The Hippo/YAP signaling pathway is a central regulator of organ growth and cell proliferation. Activation of the transcriptional co-activator and oncogene YAP (yes-associated protein) supports the development of liver cancer.

AIMS

The aim of this work was to analyze the molecular mechanisms which are responsible for YAP-induced hepatocarcinogenesis.

METHODS

YAP was silenced using siRNAs in liver cancer cell lines and effects on target gene expression were analyzed via real-time polymerase chain reaction (PCR) and western immunoblotting. Immunoprecipitation and chromatin immunoprecipitation was used to study interacting proteins and binding to target gene promoter regions, respectively. Transgenic mice with liver-specific and inducible YAP expression were used for in vivo analysis. Gene expression data from hepatocellular carcinoma (HCC) patients were used to analyze YAP-dependent gene signatures and to correlate with clinical data. HCC tissue microarrays were analyzed using immunohistochemistry.

RESULTS

Together with the transcription factors TEAD4 and FOXM1, YAP induces the expression of genes which are responsible for the development of chromosomal instability (CIN). The overexpression of these CIN genes characterizes liver cancer patients with a poor prognosis. Mechanistically, YAP/TEAD4 and FOXM1 bind to the promoter regions of the CIN genes to directly regulate their expression. The treatment of YAP-transgenic mice with a specific FOXM1 inhibitor reduces the YAP-dependent hepatomegaly, CIN gene expression and CIN. The analysis of human HCC tissue samples confirms the statistical correlation between YAP, FOXM1 and CIN.

DISCUSSION

These results reveal a new oncogenic mechanism of the Hippo/YAP signaling pathway and identify YAP and FOXM1 as potential targets for targeted therapies.

Aurora kinase A stabilizes FOXM1 to enhance paclitaxel resistance in triple-negative breast cancer

Triple-negative breast cancer (TNBC) has a relatively poor outcome. Acquired chemoresistance is a major clinical challenge for TNBC patients. Previously, we reported that kinase-dead Aurora kinase A (Aurora-A) could effectively transactivate the FOXM1 promoter. Here, we demonstrate an additional pathway through which Aurora-A stabilizes FOXM1 by attenuating its ubiquitin in TNBC. Specifically, Aurora-A stabilizes FOXM1 in late M phase and early G1 phase of the cell cycle, which promotes proliferation of TNBC cells. Knock-down of Aurora-A significantly suppresses cell proliferation in TNBC cell lines and can be rescued by FOXM1 overexpression. We observe that paclitaxel-resistant TNBC cells exhibit high expression of Aurora-A and FOXM1. Overexpression of Aurora-A offers TNBC cells an additional growth advantage and protection against paclitaxel. Moreover, Aurora-A and FOXM1 could be simultaneously targeted by thiostrepton. Combination of thiostrepton and paclitaxel treatment reverses paclitaxel resistance and significantly inhibits cell proliferation. In conclusion, our study reveals additional mechanism through which Aurora-A regulates FOXM1 and provides a new therapeutic strategy to treat paclitaxel-resistant triple-negative breast cancer.

Targeted therapies for non-HPV-related head and neck cancer: challenges and opportunities in the context of predictive, preventive, and personalized medicine

Head and neck squamous cell carcinoma (HNSCC) develops in the mucosal lining of the upper aerodigestive tract, principally as a result of exposure to carcinogens present in tobacco products and alcohol, with oncogenic papillomaviruses also being recognized as etiological agents in a limited proportion of cases. As such, there is considerable scope for prevention of disease development and progression. However, despite multimodal approaches to treatment, tumor recurrence and metastatic disease are common problems, and clinical outcome is unsatisfactory. As our understanding of the genetics and biochemical aberrations in HNSCC has improved, so the development and use of molecularly targeted drugs to combat the disease have come to the fore. In this article, we review molecular mechanisms that alter signal transduction downstream of the epidermal growth factor receptor (EGFR) as well as those that perturb orderly cell cycle progression, such as p53 mutation, cyclin overexpression, and loss of cyclin-dependent kinase inhibitor function. We outline some of the tactics that have been employed to combat the altered biochemistry. These include blockade of the EGFR using humanized monoclonal antibodies such as cetuximab and small molecule tyrosine kinase inhibitors (TKIs) such as erlotinib/gefitinib and subsequent generations of TKIs, restoration of p53 function using MIRA compounds, and inhibition of cyclin-dependent kinase and aurora kinase activity using drugs such as palbociclib and alisertib. Knowledge of the underlying molecular mechanisms may be utilizable in order to predict disease behavior and tailor therapeutic interventions in a more personalized approach to improve clinical response. Use of liquid biopsy, omics platforms, and salivary diagnostics hold promise in this regard.

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.

Prenylated xanthones from Metaxya rostrata suppress FoxM1 and induce active cell death by distinct mechanisms

BACKGROUND

Metaxya rostrata C.Presl (Metaxyaceae) is a tree fern widespread in Central and South America and the dried rhizome is used in ethnic medicine against intestinal ulcers or tumors. An activity-guided isolation resulted in two structurally related xanthones: 2-deprenyl-rheediaxanthone B (XB) and 2-deprenyl-7-hydroxy-rheediaxanthone B (OH-XB).

HYPOTHESIS/PURPOSE

This study analyzed the cytotoxic activity and underlying cellular mechanisms of OH-XB for the first time in comparison to XB.

METHODS

We exposed the colorectal cancer cell line SW480 and F331 fibroblasts to XB and OH-XB and determined cell viability by neutral red uptake and nuclear morphology by staining with Hoechst dye. Cell cycle distribution and the mechanism of cell death were analyzed by FACS and western blot. Knockdown of FoxM1 expression was performed with siRNA.

RESULTS

OH-XB was at least as cytotoxic as XB in the induction of cell cycle arrest and active cell death. While both compounds strongly inhibited the transcription factor FoxM1, the cellular mechanisms of growth arrest and cell death induction differed widely: OH-XB induced S-phase cell cycle arrest in contrast to a G2-M-phase arrest by XB. It caused morphological modifications typical for classical apoptosis with increased caspase 7 activity and enhanced cleavage of PARP, while XB caused caspase 2 activation and mitotic catastrophe. After knockdown of FoxM1 expression no induction of caspase activity could be observed.

CONCLUSION

In summary, our data clearly showed that XB and OH-XB are promising new lead compounds for cancer therapy with distinct cellular mechanisms. Both compounds are candidates for further pre-clinical and clinical investigations.

FOXM1 promotes hepatocellular carcinoma progression by regulating KIF4A expression

BACKGROUND

Forkhead box M1 (FOXM1) is a proliferation-associated transcription factor of the forkhead box proteins superfamily, which includes four isoforms FOXM1a, b, c, and d. FOXM1 has been implicated in hepatocellular carcinoma (HCC) progression, but the underlying molecular mechanism remains elusive. In this study, we aim to clarify the molecular basis for FOXM1-mediated HCC progression.

METHODS

Bioinformatic analysis was used to explore the differentially expressed genes predicting HCC proliferation. The expression of FOXM1 and kinesin family member (KIF)4A was confirmed by western blotting and immunohistochemistry in HCC tissues. Kaplan-Meier survival analysis was conducted to analyze the clinical impact of FOXM1 and KIF4A on HCC. The effect of FOXM1 on the regulation of KIF4A expression was studied in cell biology experiments. The interaction between KIF4A and FOXM1 was analyzed by chromatin immunoprecipitation and luciferase experiments. A series of experiments was performed to explore the functions of FOXM1/KIF4A in HCC progression, such as cell proliferation, cell growth, cell viability, and cell cycle. A xenograft mouse model was used to explore the regulatory effect of FOXM1-KIF4A axis on HCC tumor growth.

RESULTS

FOXM1 and KIF4A were overexpressed in human primary HCC tissues compared to that in matched adjacent normal liver tissue and are significant risk factors for HCC recurrence and shorter survival. We found that KIF4A was dominantly regulated by FOXM1c among the four isoforms, and further identified KIF4A as a direct downstream target of FOXM1c. Inhibiting FOXM1 decreased KIF4A expression in HCC cells, whereas its overexpression had the opposite effect. FOXM1-induced HCC cell proliferation was dependent on elevated KIF4A expression as KIF4A knockdown abolished FOXM1-induced proliferation of HCC cells both in vitro and in vivo.

CONCLUSION

The FOXM1-KIF4A axis mediates human HCC progression and is a potential therapeutic target for HCC treatment.

The multifaceted roles of FOXM1 in pulmonary disease

Forkhead box M1 (FOXM1), a transcriptional regulator of G1/S and G2/M transition and M phase progression in the cell cycle, plays a principal role in many physiological and pathological processes. A growing number of studies have focused on the relationship between abnormal FOXM1 expression and pulmonary diseases, such as lung cancer, chronic obstructive pulmonary disease (COPD), asthma, acute lung injury (ALI), pulmonary fibrosis, and pulmonary arterial hypertension (PAH). These studies indicate that the FOXM1 regulatory network is a major predictor of poor outcomes, especially in lung cancer, and provide novel insight into various pulmonary diseases. For the first time, this review summarizes the mechanistic relationship between FOXM1 dysregulation and pulmonary diseases, the benefits of targeting abnormal FOXM1 expression, and the questions that remain to be addressed in the future.

Pan-Cancer Analyses Reveal Genomic Features of FOXM1 Overexpression in Cancer

FOXM1 is frequently overexpressed in cancer, but this has not been studied in a comprehensive manner. We utilized genotype-tissue expression (GTEx) normal and The Cancer Genome Atlas (TCGA) tumor data to define FOXM1 expression, including its isoforms, and to determine the genetic alterations that promote FOXM1 expression in cancer. Additionally, we used human fallopian tube epithelial (FTE) cells to dissect the role of Retinoblastoma (Rb)-E2F and Cyclin E1 in FOXM1 regulation, and a novel human embryonic kidney cell (HEK293T) CRISPR FOXM1 knockout model to define isoform-specific transcriptional programs. FOXM1 expression, at the mRNA and protein level, was significantly elevated in tumors with FOXM1 amplification, p53 inactivation, and Rb-E2F deregulation. FOXM1 expression was remarkably high in testicular germ cell tumors (TGCT), high-grade serous ovarian cancer (HGSC), and basal breast cancer (BBC). FOXM1 expression in cancer was associated with genomic instability, as measured using aneuploidy signatures. FTE models confirmed a role for Rb-E2F signaling in FOXM1 regulation and in particular identified Cyclin E1 as a novel inducer of FOXM1 expression. Among the three FOXM1 isoforms, FOXM1c showed the highest expression in normal and tumor tissues and cancer cell lines. The CRISPR knockout model demonstrated that FOXM1b and FOXM1c are transcriptionally active, while FOXM1a is not. Finally, we were unable to confirm the existence of a FOXM1 auto-regulatory loop. This study provides significant and novel information regarding the frequency, causes, and consequences of elevated FOXM1 expression in human cancer.

Activation of the oncogenic transcription factor B-Myb via multisite phosphorylation and prolyl cis/trans isomerization

The oncogenic transcription factor B-Myb is an essential regulator of late cell cycle genes whose activation by phosphorylation is still poorly understood. We describe a stepwise phosphorylation mechanism of B-Myb, which involves sequential phosphorylations mediated by cyclin-dependent kinase (Cdk) and Polo-like kinase 1 (Plk1) and Pin1-facilitated peptidyl-prolyl cis/trans isomerization. Our data suggest a model in which initial Cdk-dependent phosphorylation of B-Myb enables subsequent Pin1 binding and Pin1-induced conformational changes of B-Myb. This, in turn, initiates further phosphorylation of Cdk-phosphosites, enabling Plk1 docking and subsequent Plk1-mediated phosphorylation of B-Myb to finally allow B-Myb to stimulate transcription of late cell cycle genes. Our observations reveal novel mechanistic hierarchies of B-Myb phosphorylation and activation and uncover regulatory principles that might also apply to other Myb family members. Strikingly, overexpression of B-Myb and of factors mediating its activation strongly correlates with adverse prognoses for tumor patients, emphasizing B-Myb's role in tumorigenesis.

The forkhead-box family of transcription factors: key molecular players in colorectal cancer pathogenesis

Colorectal cancer (CRC) is the third most commonly occurring cancer worldwide and the fourth most frequent cause of death having an oncological origin. It has been found that transcription factors (TF) dysregulation, leading to the significant expression modifications of genes, is a widely distributed phenomenon regarding human malignant neoplasias. These changes are key determinants regarding tumour’s behaviour as they contribute to cell differentiation/proliferation, migration and metastasis, as well as resistance to chemotherapeutic agents. The forkhead box (FOX) transcription factor family consists of an evolutionarily conserved group of transcriptional regulators engaged in numerous functions during development and adult life. Their dysfunction has been associated with human diseases. Several FOX gene subgroup transcriptional disturbances, affecting numerous complex molecular cascades, have been linked to a wide range of cancer types highlighting their potential usefulness as molecular biomarkers. At least 14 FOX subgroups have been related to CRC pathogenesis, thereby underlining their role for diagnosis, prognosis and treatment purposes.

This manuscript aims to provide, for the first time, a comprehensive review of FOX genes’ roles during CRC pathogenesis. The molecular and functional characteristics of most relevant FOX molecules (FOXO, FOXM1, FOXP3) have been described within the context of CRC biology, including their usefulness regarding diagnosis and prognosis. Potential CRC therapeutics (including genome-editing approaches) involving FOX regulation have also been included. Taken together, the information provided here should enable a better understanding of FOX genes’ function in CRC pathogenesis for basic science researchers and clinicians.

FOXM1c promotes oesophageal cancer metastasis by transcriptionally regulating IRF1 expression

Objectives

We aimed to elucidate the role and molecular mechanisms of FOXM1 in regulating metastasis in oesophageal squamous cell carcinoma (ESCC) as well as its clinical implications.

Materials and methods

The expression levels of four isoforms of FOXM1 were analysed by real‐time PCR. Next, genetically modification using overexpression and RNAi systems and transwell were employed to examine FOXM1c function in invasion and migration. Dual luciferase and ChIP assays were performed to decipher the underlying mechanism for transcriptional regulation. The expression levels of FOXM1 and IRF1 were determined by immunohistochemistry staining in ESCC specimens.

Results

The FOXM1c was predominantly overexpressed in ESCC cell lines compared to the other FOXM1 isoforms. Ectopic expression of FOXM1c promoted invasion and migration of ESCC cells lines, whereas downregulation of FOXM1c inhibited these processes. Moreover, FOXM1c expression was positively correlated with IRF1 expression in ESCC cell lines and tumour specimens. IRF1 is, at least in part, responsible for FOXM1c‐mediated invasion and migration. Mechanistically, we identified IRF1 as a transcriptional target of FOXM1c and found a FOXM1c‐binding site in the IRF1 promoter region. Furthermore, high expression levels of both FOXM1c and IRF1 were positively associated with low survival rate and predicted a poor prognosis of oesophageal cancer patients.

Conclusion

FOXM1c promotes the metastasis by transcriptionally targeting IRF1 and may serve as a potential prognostic predictor for oesophageal cancer.

The Dominant Role of Forkhead Box Proteins in Cancer

Forkhead box (FOX) proteins are multifaceted transcription factors that are significantly implicated in cancer, with various critical roles in biological processes. Herein, we provide an overview of several key members of the FOXA, FOXC, FOXM1, FOXO and FOXP subfamilies. Important pathophysiological processes of FOX transcription factors at multiple levels in a context-dependent manner are discussed. We also specifically summarize some major aspects of FOX transcription factors in association with cancer research such as drug resistance, tumor growth, genomic alterations or drivers of initiation. Finally, we suggest that targeting FOX proteins may be a potential therapeutic strategy to combat cancer.

Lentiviral RNA interference-mediated downregulation of Forkhead box M1 expression suppresses growth of oral squamous cell carcinoma in vitro

Oral squamous cell carcinoma (OSCC) is one of the most fatal types of oral cancer worldwide. Forkhead box M1 (FOXM1) is associated with the occurrence and development of a number of types of human cancer, but its function in OSCC remains unclear. The present study aimed to explore the effect of FOXM1 downregulation using lentivirus-mediated short hairpin (sh)RNA against FOXM1 (LV-shFOXM1) in the cell line Tca8113 in vitro. Infection of Tca8113 cells with LV-shFOXM1 inhibited the mRNA and protein expression level of FOXM1. The downregulation of FOXM1 resulted in cell cycle arrest of Tca8113 cells, and the inhibition of proliferation, migration and invasion. The protein expression level of cyclins B1 and D1 were downregulated, whereas those of p27 and p21 were upregulated following infection with LV-shFOXM1, compared with the blank control and LV-shCON groups. In addition, FOXM1 downregulation decreased the expression of matrix metalloproteinase-2 and LV-shFOXM1 significantly suppressed OSCC cell viability. Therefore, FOXM1 may be a target for the treatment of OSCC.

FOXM1 contributes to treatment failure in acute myeloid leukemia

Acute myeloid leukemia (AML) patients with NPM1 mutations demonstrate a superior response to standard chemotherapy treatment. Our previous work has shown that these favorable outcomes are linked to the cytoplasmic relocalization and inactivation of FOXM1 driven by mutated NPM1. Here, we went on to confirm the important role of FOXM1 in increased chemoresistance in AML. A multiinstitution retrospective study was conducted to link FOXM1 expression to clinical outcomes in AML. We establish nuclear FOXM1 as an independent clinical predictor of chemotherapeutic resistance in intermediate-risk AML in a multivariate analysis incorporating standard clinicopathologic risk factors. Using colony assays, we show a dramatic decrease in colony size and numbers in AML cell lines with knockdown of FOXM1, suggesting an important role for FOXM1 in the clonogenic activity of AML cells. In order to further prove a potential role for FOXM1 in AML chemoresistance, we induced an FLT3-ITD-driven myeloid neoplasm in a FOXM1-overexpressing transgenic mouse model and demonstrated significantly higher residual disease after standard chemotherapy. This suggests that constitutive overexpression of FOXM1 in this model induces chemoresistance. Finally, we performed proof-of-principle experiments using a currently approved proteasome inhibitor, ixazomib, to target FOXM1 and demonstrated a therapeutic response in AML patient samples and animal models of AML that correlates with the suppression of FOXM1 and its transcriptional targets. Addition of low doses of ixazomib increases sensitization of AML cells to chemotherapy backbone drugs cytarabine and the hypomethylator 5-azacitidine. Our results underscore the importance of FOXM1 in AML progression and treatment, and they suggest that targeting it may have therapeutic benefit in combination with standard AML therapies.

FGFR1/FOXM1 pathway: a key regulator of glioblastoma stem cells radioresistance and a prognosis biomarker

Glioblastoma are known to be aggressive and therapy-resistant tumors, due to the presence of glioblastoma stem cells inside this heterogeneous tumor. We investigate here the involvement of FGFR1 in glioblastoma stem-like cells (GSLC) radioresistance mechanisms. We first demonstrated that the survival after irradiation was significantly diminished in FGFR1-silenced (FGFR1-) GSLC compared to control GSLC. The transcriptome analysis of GSLCs FGFR1(-) showed that FOX family members are differentially regulated by FGFR1 inhibition, particularly with an upregulation of FOXN3 and a downregulation of FOXM1. GSLC survival after irradiation was significantly increased after FOXN3 silencing and decreased after FOXM1 inhibition, showing opposite effects of FGFR1/FOX family members on cell response to ionizing radiation. Silencing FGFR1 or FOXM1 downregulated genes involved in mesenchymal transition such as GLI2, TWIST1, and ZEB1 in glioblastoma stem-like cells. It also dramatically reduced GSLC migration. Databases analysis confirmed that the combined expression of FGFR1/FOXM1/MELK/GLI2/ZEB1/TWIST1 is significantly associated with patients overall survival after chemo-radiotherapy treatment. All these results, associated with our previous conduced ones with differentiated cells, clearly established that FGFR1-FOXM1 dependent glioblastoma stem-like cells radioresistance pathway is a central actor of GBM treatment resistance and a key target to inhibit in the aim to increase the sensitivity of GBM to the radiotherapy.

The Treatment Landscape and New Opportunities of Molecular Targeted Therapies in Gastroenteropancreatic Neuroendocrine Tumors

Neuroendocrine neoplasms (NENs) are a heterogeneous group of neoplasms that originate from neuroendocrine stem cells and express both neural and endocrine markers. They are found in almost every organ, and while NENs are mostly associated with slow growth, complications due to the uncontrolled secretion of active peptides, and metastatic disease, may significantly impair the quality of life and can ultimately lead to the death of affected individuals. Expanding knowledge of the genetic, epigenetic, and proteomic landscapes of NENs has led to a better understanding of their molecular pathology and consequently increased treatment options for patients. Here, we review the principal breakthroughs in NEN treatment management, owing largely to omics technologies over the last few years, current recommendations of systemic treatment, and ongoing research into the identification of predictive and response biomarkers based on molecular targeted therapies.

Sphingosine-1-phosphate induces airway smooth muscle cell proliferation, migration, and contraction by modulating Hippo signaling effector YAP

Sphingosine-1-phosphate (S1P), a bioactive lipid, has been shown to be elevated in the airways of individuals with asthma and modulates the airway smooth muscle cell (ASMC) functions, yet its underlying molecular mechanisms are not completely understood. The aim of the present study is to address this issue. S1P induced yes-associated protein (YAP) dephosphorylation and nuclear localization via the S1PR_2/3/Rho-associated protein kinase (ROCK) pathway, and this in turn increased forkhead box M1 (FOXM1) and cyclin D1 expression leading to ASMC proliferation, migration, and contraction. Pretreatment of cells with S1PR₂ antagonist JTE013, S1PR₃ antagonist CAY10444, or ROCK inhibitor Y27632 blocked S1P-induced alterations of YAP, FOXM1, cyclin D1, and ASMC proliferation, migration, and contraction. In addition, prior silencing of YAP or FOXM1 with siRNA reversed the effect of S1P on ASMC functions. Taken together, our study indicates that S1P stimulates ASMC proliferation, migration, and contraction by binding to S1PR_2/3 and modulating ROCK/YAP/FOXM1 axis and suggests that targeting this pathway might have potential value in the management of asthma.

Inhibition of maternal embryonic leucine zipper kinase with OTSSP167 displays potent anti-leukemic effects in chronic lymphocytic leukemia

TP53 pathway defects contributed to therapy resistance and adverse clinical outcome in chronic lymphocytic leukemia (CLL), which represents an unmet clinical need with few therapeutic options. Maternal embryonic leucine zipper kinase (MELK) is a novel oncogene, which plays crucial roles in mitotic progression and stem cell maintenance. OTSSP167, an orally administrated inhibitor targeting MELK, is currently in a phase I/II clinical trial in patients with advanced breast cancer and acute myeloid leukemia. Yet, no investigation has been elucidated to date regarding the oncogenic role of MELK and effects of OTSSP167 in chronic lymphocytic leukemia (CLL). Previous studies confirmed MELK inhibition abrogated cancer cell survival via p53 signaling pathway. Thus, we aimed to determine the biological function of MELK and therapeutic potential of OTSSP167 in CLL. Herein, MELK over-expression was observed in CLL cells, and correlated with higher WBC count, advanced stage, elevated LDH, increased β2-MG level, unmutated IGHV, positive ZAP-70, deletion of 17p13 and inferior prognosis of CLL patients. In accordance with functional enrichment analyses in gene expression profiling, CLL cells with depletion or inhibition of MELK exhibited impaired cell proliferation, enhanced fast-onset apoptosis, induced G2/M arrest, attenuated cell chemotaxis and promoted sensitivity to fludarabine and ibrutinib. However, gain-of-function assay showed increased cell proliferation and cell chemotaxis. In addition, OTSSP167 treatment reduced phosphorylation of AKT and ERK1/2. It decreased FoxM1 phosphorylation, expression of FoxM1, cyclin B1 and CDK1, while up-regulating p53 and p21 expression. Taken together, MELK served as a candidate of therapeutic target in CLL. OTSSP167 exhibits potent anti-tumor activities in CLL cells, highlighting a novel molecule-based strategy for leukemic interventions.

Expression and functional characterization of FOXM1 in non-small cell lung cancer

Objectives

FOXM1 is a key member of the FOX transcription factor family, which plays a vital role in a series of physiological processes. In the present study, non-small cell lung cancer (NSCLC) patients and cell lines were studied to explore the correlation between FOXM1 expression and this malignancy.

Materials and methods

The expression status of FOXM1 was detected in 128 cases of NSCLC tissues and NSCLC cell lines. The relationship of FOXM1 expression and clinicopathological features of NSCLC patients was evaluated by us. In addition, we also explored the biological functions of FOXM1 in NSCLC cell lines.

Results

The FOXM1 is highly expressed in NSCLC tissues and cell lines. FOXM1 expression was closely correlated with lymph node status and TNM stage. Cox regression analysis were performed to demonstrate the prognosis role of FOXM1.

Conclusion

FOXM1 conferred a proliferation and invasion advantage to NSCLC cell. The FOXM1 can be regarded as an important molecular marker in NSCLC prognosis.

FOXM1: A potential indicator to predict lymphatic metastatic recurrence in stage IIA esophageal squamous cell carcinoma

BACKGROUND

Previous studies have elucidated that FOXM1 may predict poor prognosis in patients with multiple solid malignant tumors. In this study we explored the differential expression of FOXM1 in stage IIA esophageal squamous cell carcinoma (ESCC) and investigated its prognostic value.

METHODS

Immunohistochemistry (IHC) and Western blot were used to detect FOXM1 expression in ESCC. Correlations between FOXM1 expression and clinicopathological variables, and five-year lymphatic metastatic recurrence (LMR) and overall survival (OS) of patients were analyzed.

RESULTS

FOXM1 was aberrantly expressed in ESCC. Statistical analysis revealed a close relationship between FOXM1 expression and tumor size (P = 0.024), depth of invasion (P = 0.048), and degree of differentiation (P = 0.043). The five-year LMR of patients in the FOXM1 overexpression group was significantly increased compared to the low expression group (P = 0.001). The five-year OS of patients in the FOXM1 overexpression group was significantly reduced compared to the low expression group (P = 0.007). Log-rank tests demonstrated that large tumor size (P = 0.044), poor differentiation degree (P = 0.005), deep invasion (P = 0.000), and FOXM1 overexpression (P = 0.007) may indicate poor prognosis in stage IIA ESCC. Cox multivariate regression analysis revealed that all of these variables were independent predictors of unfavorable outcome (P < 0.05).

CONCLUSION

FOXM1 could be a predictor of lymphatic metastatic recurrence in stage IIA ESCC after Ivor Lewis esophagectomy.