FOXC2 regulates the G2/M transition of stem cell-rich breast cancer cells and sensitizes them to PLK1 inhibition

GDF10 promotes rodent cardiomyocyte maturation during the postnatal period

Cardiomyocytes and cardiac fibroblasts undergo coordinated maturation after birth, and cardiac fibroblasts are required for postnatal cardiomyocyte maturation in mice. Here, we investigate the role of cardiac fibroblast-expressed Growth Differentiation Factor 10 (GDF10) in postnatal heart development. In neonatal mice, Gdf10 is expressed specifically in cardiac fibroblasts, with its highest expression coincident with the onset of cardiomyocyte cell cycle arrest and transition to hypertrophic growth. In neonatal rat ventricular myocyte (NRVM) cultures, GDF10 treatment promotes cardiomyocyte maturation indicated by increased binucleation, downregulation of cell cycle progression genes, and upregulation of cell cycle inhibitor genes. GDF10 treatment leads to an increase in cardiomyocyte cell size, together with increased expression of mature sarcomeric protein isoforms and decreased expression of fetal cardiac genes. RNAsequencing of GDF10-treated NRVM shows an increase in the expression of genes related to myocardial maturation, including upregulation of sodium and potassium channel genes. In vivo, loss of Gdf10 leads to a delay in myocardial maturation indicated by decreased cardiomyocyte cell size and binucleation, as well as increased mitotic activity, at postnatal (P) day 7. Further, induction of mature sarcomeric protein isoform gene expression is delayed, and expression of cell cycle progression genes is prolonged. However, by P10, indicators of cardiomyocyte maturation and mitotic activity are normalized in Gdf10-null hearts relative to controls. Together, these results implicate GDF10 as a novel crosstalk mediator between cardiomyocytes and cardiac fibroblasts, which is required for appropriate timing of cardiomyocyte maturation steps including binucleation, hypertrophy, mature sarcomeric isoform gene expression, and cell cycle arrest in the postnatal period.

Integrative Analysis of DNA Methylation and microRNA Reveals GNPDA1 and SLC25A16 Related to Biopsychosocial Factors Among Taiwanese Women with a Family History of Breast Cancer

Biopsychosocial factors, including family history, influence the development of breast cancer. Malignancies in women with a family history of breast cancer may be detectable based on DNA methylation and microRNA. Objectives: The present study extended an integrative analysis of DNA methylation and microRNA to identify genes associated with biopsychosocial factors. Methods: We identified 3060 healthy women from the Taiwan Biobank and included 32 blood plasma samples for analysis of biopsychosocial factors and epigenetic changes. GEO databases and bioinformatics approaches were used for the identification and validation of potential genes. Results: Our integrative analysis revealed GNPDA1 and SLC25A16 as potential genes. Age, a family history of cancer, and alcohol consumption were associated with GNPDA1 and SLC25A16 based on the current data set and the GEO data set. GNPDA1 and SLC25A16 exhibited significant expression in breast cancer tissues based on UALCAN analysis, where they were overexpressed and underexpressed, respectively. Through a MethSurv analysis, GNPDA1 hypomethylation and SLC25A16 hypermethylation were associated with poor prognoses in terms of overall survival in breast cancer. Moreover, through a MetaCore functional enrichment analysis, GNPDA1 and SLC25A16 were associated with the BRCA1, BRCA2, and pro-oncogenic actions of the androgen receptor in breast cancer. Further, GNPDA1 and SLC25A16 were enriched in known targets of approved cancer drugs as potential genes associated with breast cancer. Conclusions: These two genes might serve as biomarkers for the early detection of breast cancer, especially for women with a family history of breast cancer.

β-Catenin Drives the FOXC2-Mediated Epithelial-Mesenchymal Transition and Acquisition of Stem Cell Properties

Background: Aggressive forms of breast cancer, such as triple-negative breast cancer (TNBC), are associated with an increase in cancer cells that exhibit stem cell properties. The activation of the epithelial-mesenchymal transition (EMT) program, mediated by the transcription factor FOXC2, generates these stem-like cells. FOXC2 is linked to poor prognoses across various cancer types and is notably upregulated in TNBC, where it establishes and sustains these stem-like cells within the tumor population. Methods: Here, we decode the pathways regulating FOXC2 activation using EMT-enriched cell line models. Stemness was assessed using mammosphere assays and mesenchymal markers by western blot. Expression correlations with clinical data was examined using the EMTome. Results: We demonstrate that β-catenin serves as a critical mediator of mesenchymal and stemness characteristics through FOXC2 upregulation. By disrupting β-catenin, we find that FOXC2 expression, mesenchymal properties, and stemness are reduced; however, the introduction of exogenous FOXC2 expression in β-catenin deficient cells is enough to restore the mesenchymal and stemness phenotype. These findings support the idea that FOXC2 acts as the downstream regulator of β-catenin and influences both mesenchymal and stemness properties. Moreover, there is a positive correlation between the expression of β-catenin and FOXC2 in various cancer subtypes observed in clinical patient samples. Conclusions: Our study clarifies the role of the β-catenin/FOXC2 signaling axis in maintaining stemness properties, suggesting potential targets for TNBC and other cancers driven by EMT-related mesenchymal and stemness characteristics.

The role of transcription factor FOXA1/C2/M1/O3/P1/Q1 in breast cancer

Breast cancer is a common malignancy with the highest mortality rate among women worldwide. Its incidence is on the rise year after year, accounting for more than one-tenth of new cancers worldwide. Increasing evidence suggests that forkhead box (FOX) transcription factors play an important role in the occurrence and development of breast cancer. However, little is known about the relationship between the expression, prognostic value, function, and immune infiltration of FOX transcription factors in tumor microenvironment. We used bioinformatics to investigate expression and function of FOX factor in breast cancer. Our results revealed the expression levels of FOXA1 and FOXM1 were significantly higher in breast cancer tissues than in normal tissues. The high expression of mRNA in FOXA1 (P < .05), FOXM1 (P < .01), and FOXP1 (P < .05) groups was related to tumor stage. Survival analysis results showed that increased FOXP1 mRNA levels were significantly associated with overall survival (OS), recurrence-free survival (RFS), and distant metastasis-free survival (DMFS) in all patients with breast cancer (P < .05). Patients with the FOXA1 high-expression group had better RFS and DMFS than the low-expression group (P < .05), while patients with FOXM1 high-expression group had worse RFS, OS, and DMFS than the low-expression group (P < .05). Meanwhile, mutation analysis showed that genetic alterations in FOX transcription factors were significantly associated with shorter OS and progression-free survival (P < .05), but not with disease-free survival (P = .710) in patients with breast cancer. FOXP1, FOXA1, and FOXM1 may be used as potential biomarkers to predict the prognosis of patients with breast cancer. Functional enrichment indicated that FOX was mainly involved in cell division, cell senescence, cell cycle, and prolactin signaling pathway. In patients with breast cancer, FOXC2 expression was negatively correlated with the infiltration of B cells and positively correlated with the infiltration of neutrophils and dendritic cells. However, FOXM1 was negatively correlated with the infiltration of CD8 + T cells and macrophages and positively correlated with the infiltration of neutrophils and dendritic cells. These findings provided novel insights into the screening of prognostic biomarkers of the FOX family in breast cancer and laid a foundation for further research on the immune infiltration of the FOX transcription factor family members in tumors.

Spatial and Temporal Relationship between Epithelial-Mesenchymal Transition (EMT) and Stem Cells in Cancer

BACKGROUND

Epithelial-mesenchymal transition (EMT) is often linked with carcinogenesis. However, EMT is also important for embryo development and only reactivates in cancer. Connecting how EMT occurs during embryonic development and in cancer could help us further understand the root mechanisms of cancer diseases.

CONTENT

There are key regulatory elements that contribute to EMT and the induction and maintenance of stem cell properties during embryogenesis, tissue regeneration, and carcinogenesis. Here, we explore the implications of EMT in the different stages of embryogenesis and tissue development. We especially highlight the necessity of EMT in the mesodermal formation and in neural crest cells. Through EMT, these cells gain epithelial-mesenchymal plasticity (EMP). With this transition, crucial morphological changes occur to progress through the metastatic cascade as well as tissue regeneration after an injury. Stem-like cells, including cancer stem cells, are generated from EMT and during this process upregulate factors necessary for stem cell maintenance. Hence, it is important to understand the key regulators allowing stem cell awakening in cancer, which increases plasticity and promotes treatment resistance, to develop strategies targeting this cell population and improve patient outcomes.

SUMMARY

EMT involves multifaceted regulation to allow the fluidity needed to facilitate adaptation. This regulatory mechanism, plasticity, involves many cooperating transcription factors. Additionally, posttranslational modifications, such as splicing, activate the correct isoforms for either epithelial or mesenchymal specificity. Moreover, epigenetic regulation also occurs, such as acetylation and methylation. Downstream signaling ultimately results in the EMT which promotes tissue generation/regeneration and cancer progression.

Stabilizing vimentin phosphorylation inhibits stem-like cell properties and metastasis of hybrid epithelial/mesenchymal carcinomas

Epithelial-mesenchymal transition (EMT) empowers epithelial cells with mesenchymal and stem-like attributes, facilitating metastasis, a leading cause of cancer-related mortality. Hybrid epithelial-mesenchymal (E/M) cells, retaining both epithelial and mesenchymal traits, exhibit heightened metastatic potential and stemness. The mesenchymal intermediate filament, vimentin, is upregulated during EMT, enhancing the resilience and invasiveness of carcinoma cells. The phosphorylation of vimentin is critical to its structure and function. Here, we identify that stabilizing vimentin phosphorylation at serine 56 induces multinucleation, specifically in hybrid E/M cells with stemness properties but not epithelial or mesenchymal cells. Cancer stem-like cells are especially susceptible to vimentin-induced multinucleation relative to differentiated cells, leading to a reduction in self-renewal and stemness. As a result, vimentin-induced multinucleation leads to sustained inhibition of stemness properties, tumor initiation, and metastasis. These observations indicate that a single, targetable phosphorylation event in vimentin is critical for stemness and metastasis in carcinomas with hybrid E/M properties.

Proactive and reactive roles of TGF-β in cancer

Cancer cells adapt to varying stress conditions to survive through plasticity. Stem cells exhibit a high degree of plasticity, allowing them to generate more stem cells or differentiate them into specialized cell types to contribute to tissue development, growth, and repair. Cancer cells can also exhibit plasticity and acquire properties that enhance their survival. TGF-β is an unrivaled growth factor exploited by cancer cells to gain plasticity. TGF-β-mediated signaling enables carcinoma cells to alter their epithelial and mesenchymal properties through epithelial-mesenchymal plasticity (EMP). However, TGF-β is a multifunctional cytokine; thus, the signaling by TGF-β can be detrimental or beneficial to cancer cells depending on the cellular context. Those cells that overcome the anti-tumor effect of TGF-β can induce epithelial-mesenchymal transition (EMT) to gain EMP benefits. EMP allows cancer cells to alter their cell properties and the tumor immune microenvironment (TIME), facilitating their survival. Due to the significant roles of TGF-β and EMP in carcinoma progression, it is essential to understand how TGF-β enables EMP and how cancer cells exploit this plasticity. This understanding will guide the development of effective TGF-β-targeting therapies that eliminate cancer cell plasticity.

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.

Virtual screening of natural compounds as selective inhibitors of polo-like kinase-1 at C-terminal polo box and N-terminal catalytic domain

The over-expression of Polo-like kinase-1 (PLK1) is associated with cancer prognosis due to its pivotal role in cell proliferation. The N-terminal catalytic domain (NCD) and C-terminal polo box domain (PBD) of PLK1 are critical for the activity of the protein. Drugs that inhibit PLK1 by targeting these domains are on clinical trials, but so far, none has been approved by FDA. Thus, this study targets the two domains of PLK1 to identify compounds with inhibitory potential. Four validated e-pharmacophore models from NCD (PDB ID: 2OU7 and 4J52) and PBD (PDB ID: 5NEI and 5NN2) were used to screen over 26,000 natural compounds from NPASS database. Hits were identified after the well-fitted compounds were subjected to molecular docking study and ADME prediction. The pIC50 and electronic behaviour of the identified hits selectively targeting NCD and PBD of PLK1 were predicted via an externally validated QSAR model and quantum mechanics. The results showed that CAA180504, CAA197326, CAA74619, CAA328856 modulating PLK1 at NCD, and CBB130581, CBB230713, CBB206123, CBB12656 and CBB267117 modulating PLK1 at PBD had better molecular docking scores, pharmacokinetics and drug-like properties than NCD (volasertib) and PBD (purpurogallin) reference inhibitors. The compounds all had satisfactory inhibitory (pIC50) values which range from 6.187 to 7.157. The electronic behaviours of understudied compounds using HOMO/LUMO and global descriptive parameters revealed the atomic portion of the compounds prone to donating and accepting electrons. In conclusion, the hit compounds identified from the library of natural compounds are worthy of further experimental validation.Communicated by Ramaswamy H. Sarma.

Forkhead Box Transcription Factors: Double-Edged Swords in Cancer

A plethora of treatment options exist for cancer therapeutics, but many are limited by side effects and either intrinsic or acquired resistance. The need for more effective targeted cancer treatment has led to the focus on forkhead box (FOX) transcription factors as possible drug targets. Forkhead factors such as FOXA1 and FOXM1 are involved in hormone regulation, immune system modulation, and disease progression through their regulation of the epithelial-mesenchymal transition. Forkhead factors can influence cancer development, progression, metastasis, and drug resistance. In this review, we discuss the various roles of forkhead factors in biological processes that support cancer as well as their function as pioneering factors and their potential as targetable transcription factors in the fight against cancer.

miR-509 inhibits cancer stemness properties in oral carcinomas via directly targeting PlK1

Background/purpose

Oral cancer is one of the common cancers worldwide. Emerging evidence has indicated that microRNAs (non-coding RNA molecules of approximately 22 nucleotides in length) are implicated in the regulation of cancer stemness. However, the functional role of microRNA-509 (miR-509) in the characteristics of oral cancer stem cells (CSCs) has not been unraveled.

Materials and methods

The expression level of miR-509 in ALDH1⁺ and sphere oral CSCs was examined by qRT-PCR. The aldehyde dehydrogenase 1 (ALDH1) activity and CD44 expression were assessed using flow cytometry. Self-renewal, transwell migration, and colony formation assays were conducted to measure the CSC phenotypes. Besides, a luciferase reporter assay was used to confirm the direct interaction between miR-509 and its target polo-like kinase 1 (plk1).

Results

We showed the expression of miR-509 was downregulated in the CSCs derived from oral cancer cells (SAS), and upregulation of miR-509 diminished the several CSCs features, including ALDH1 activity, self-renewal capacity, CD44 expression, migration, and colony-forming abilities. Moreover, the result from the luciferase reporter assay validated the direct binding of miR-509 to plk1.

Conclusion

Our results suggest that the miR-509/plk1 axis may mediate the cancer stemness in oral cancer, and targeting this axis may attenuate the progression of oral cancer.

A Novel Allosteric Inhibitor Targets PLK1 in Triple Negative Breast Cancer Cells

While Polo-like kinase 1 (PLK1) inhibitors have shown promise in clinical settings for treating triple-negative breast cancer tumors and other solid tumors, they are limited by their ability to bind non-selectively to the ATP kinase domain. Therefore, we sought to develop a PLK1 allosteric inhibitor targeting the PLK1 T-loop (a switch responsible for activation) and evaluate its effects in triple-negative breast cancer cells. A novel compound, RK-10, was developed based on an in silico model, and its effects on specificity, viability, migration, and cell cycle regulation in MCF-10A and MDA-MB 231 cells were evaluated. When MDA-MB 231 cells were treated with 0−50 µg/mL RK-10, phospho-PLK1 (Thr-210) was decreased in cells cultured adherently and cells cultured as mammospheres. RK-10 significantly inhibited viability after 24 h; however, by 48 h, 25−50 µM RK-10 caused >50% reduction. RK-10 attenuated wound healing by up to 99.7% and caused S and G2/M cell cycle arrest, which was associated with increased p21 expression. We developed a novel allosteric inhibitor which mediates anti-proliferative and anti-migratory properties through targeting phospho-PLK1 (Thr-210) in mammospheres and causing S phase and G2/M cell cycle arrest. Further development of PLK1 allosteric inhibitors may be a promising approach for TNBC treatment.

Molecular targets and therapeutics in chemoresistance of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a specific subtype of breast cancer (BC), which shows immunohistochemically negative expression of hormone receptor i.e., Estrogen receptor and Progesterone receptor along with the absence of Human Epidermal Growth Factor Receptor-2 (HER2/neu). In Indian scenario the prevalence of BC is 26.3%, whereas, in West Bengal the cases are of 18.4%. But the rate of TNBC has increased up to 31% and shows 27% of total BC. Conventional chemotherapy is effective only in the initial stages but with progression of the disease the effectivity gets reduced and shown almost no effect in later or advanced stages of TNBC. Thus, TNBC patients frequently develop resistance and metastasis, due to its peculiar triple-negative nature most of the hormonal therapies also fails. Development of chemoresistance may involve various factors, such as, TNBC heterogeneity, cancer stem cells (CSCs), signaling pathway deregulation, DNA repair mechanism, hypoxia, and other molecular factors. To overcome the challenges to treat TNBC various targets and molecules have been exploited including CSCs modulator, drug efflux transporters, hypoxic factors, apoptotic proteins, and regulatory signaling pathways. Moreover, to improve the targets and efficacy of treatments researchers are emphasizing on targeted therapy for TNBC. In this review, an effort has been made to focus on phenotypic and molecular variations in TNBC along with the role of conventional as well as newly identified pathways and strategies to overcome challenge of chemoresistance.

Gene Expression Analysis Reveals Key Genes and Signalings Associated with the Prognosis of Prostate Cancer

It is urgent to identify novel biomarkers for prostate cancer (PCa) prognosis and to understand the mechanisms regulating the tumorigenesis for PCa treatment. In this study, GSE17951 and TCGA were used to identify the differentially expressed genes (DEGs). Our study demonstrated that 1533 genes with increased expression and 2301 genes with decreased expression in PCa. Bioinformatics analysis data indicated that these up-regulated genes had an association with the modulation of mitotic nuclear division, sister chromatid cohesion, cell division, and cell cycle. Additionally, our results revealed downregulated genes took part in modulating extracellular matrix organization, angiogenesis, signal transduction, and Ras signaling pathway. Hub upregulated and downregulated PPI networks were identified by protein-protein interaction (PPI) network analysis and MCODE analysis. Of note, 12 cell cycle regulators, comprising CCNB1, CCNB2, PLK1, TTK, AURKA, CDC20, BUB1, PTTG1, CDC45, CDC25C, CCNA2, and BUB1B, were demonstrated to function crucially in PCa development. By detecting their expression in PCa cell lines, we confirmed that these cell cycle regulator expressions were heightened in PCa cells. GEPIA databases analysis showed that higher expression of these cell cycle regulators was correlated to shorter disease-free survival (DFS) time in PCa samples. Our findings collectively suggested targeting cell cycle pathways may offer novel prognosis and treatment biomarkers for PCa.

The prognostic significance of FOXC2 gene expression in cancer: A comprehensive analysis of RNA-seq data from the cancer genome atlas

The FOXC2 transcription factor is a key regulator of tumor progression in many cancer types. Known to exhibit an array of oncogenic functions when dysregulated, FOXC2 has emerged as a useful biomarker for predicting disease aggression and patient outcome. In this regard, increased expression and nuclear localization of FOXC2 protein in tumor tissue have become well-established as poor prognostic factors for many cancer types. However, whether FOXC2 gene expression can serve as a similarly useful RNA-level biomarker has remained largely unexplored. Therefore, we conducted a comprehensive analysis of TCGA RNA-seq data to evaluate whether FOXC2 gene expression levels in primary tumor biopsies correlate with patient outcome. We report herein that increased expression of FOXC2 RNA in tumor tissue is a poor prognostic factor for patient survival in many cancer types. Moreover, we also found that FOXC2 gene expression predicts cancer patient response to several commonly prescribed chemotherapeutics. Together, these data highlight FOXC2 RNA expression in tumor tissue as an important biomarker with prognostic significance for solid tumors of diverse origin.

Transitional dynamics of cancer stem cells in invasion and metastasis

At the onset, few cancer cells amidst the tumor bulk, identified as cancer stem cells (CSCs) or early disseminated cancer cells (eDCCs) are capable of survival post conventional therapy and persist as minimal residual disease (MRD). Metastatic subclones emerge both early and late in the life of primary tumor ensuing an ongoing regional clonal evolution of progenitor cells in metastatic and primary tumors. In the last decade, multiple studies proposed various identities of stem-like cells that undergo transitions to adapt to the changing microenvironment as the disease progresses. This review advocates with substantial evidence the dynamic model of tumor propagation by exploring the specific cell types, reversible phenotypic plasticity between the tumorigenic leader seeds and the supporting follower cancer cells both in circulation and in solid tissue to accurately decipher tumor promoting clones and its role in metastatic dissemination and tumor re-growth. (142 words).

FOXC2 Promotes Oxaliplatin Resistance by Inducing Epithelial-Mesenchymal Transition via MAPK/ERK Signaling in Colorectal Cancer

Background

Chemoresistance is a major obstacle to improving the survival rate of colorectal cancer (CRC) patients. Forkhead box protein C2 (FOXC2), a member of the forkhead box (Fox) transcription factor family, is reported to be an important regulator of epithelial-to-mesenchymal transition (EMT) and plays a key role in tumor progression. However, little is known about the effects of FOXC2 on oxaliplatin (OXA) resistance in CRC.

Methods

OXA-resistant cells were generated from HCT116 cells. CCK-8, colony formation, flow cytometry and Transwell assays were used to compare the characteristics of OXA-resistant HCT116/OXA cells and the corresponding parental HCT116 cells. The expression of FOXC2 was confirmed by qRT-PCR and Western blotting in HCT116/OXA and HCT116 cells. Gain- and loss-of-function assays were performed to evaluate the effects of FOXC2 on OXA sensitivity and EMT in HCT116/OXA and HCT116 cells both in vitro and in vivo, and the possible molecular mechanisms were investigated.

Results

The relative expression of FOXC2 was significantly increased in HCT116/OXA cells compared with the parental HCT116 cells. Upregulation of FOXC2 in HCT116 cells reduced OXA sensitivity and promoted EMT. However, knockdown of FOXC2 in HCT116/OXA cells markedly increased the in vitro and in vivo sensitivity of HCT116/OXA cells to OXA by regulating EMT progression. Furthermore, FOXC2 activated MAPK/ERK signaling, and blockade of ERK attenuated FOXC2-induced EMT and FOXC2-enhanced OXA resistance.

Conclusion

FOXC2 induced EMT to promote oxaliplatin resistance by activating the MAPK/ERK signaling pathway. FOXC2 may be a potential therapeutic target for overcoming OXA resistance in human CRC.

Phosphorylation of the histone demethylase KDM5B and regulation of the phenotype of triple negative breast cancer

Epigenetic modifications are known to play critical roles in the expression of genes related to differentiation and dedifferentiation. Histone lysine demethylase KDM5B (PLU-1) catalyzes the demethylation of histone H3 on Lys 4 (H3K4), which results in the repression of gene expression. KDM5B is involved in regulation of luminal and basal cell specific gene expression in breast cancers. However, the mechanisms by which KDM5B is regulated in breast cancer, in particular in response to post-translational signals is not well-defined. Here, we demonstrate that KDM5B is phosphorylated at Ser1456 by the cyclin-dependent kinase 1 (CDK1). Phosphorylation of KDM5B at Ser1456 attenuated the occupancy of KDM5B on the promoters of pluripotency genes. Moreover, KDM5B inhibited the expression of pluripotency genes, SOX2 and NANOG, and decreased the stem cell population in triple-negative breast cancer cell lines (TNBC). We previously reported that the tumor suppressor HEXIM1 is a mediator of KDM5B recruitment to its target genes, and HEXIM1 is required for the inhibition of nuclear hormone receptor activity by KDM5B. Similarly, HEXIM1 is required for regulation of pluripotency genes by KDM5B.

Emerging roles and mechanisms of FOXC2 in cancer

Forkhead box protein C2 (FOXC2), a transcription factor of the forkhead/winged-helix family, is required for embryonic and prenatal development. FOXC2 acts as a crucial modulator during both angiogenesis and lymphangiogenesis via multiple angiogenic and lymphangiogenic pathways, respectively. Although recent studies have shed light on the emerging role of FOXC2 in cancer, very little is known about the precise underlying mechanisms. The purpose of this review is to summarize the current understanding of FOXC2 and provide potential mechanistic explanations of the relationship between FOXC2 and cancer, as well as discuss the prospect for future research in the promising prognostic value of FOXC2 in cancer.

Role and importance of the expression of transcription factor FOXC2 in cervical cancer

The aim of the present study was to investigate the relationship between the expression of transcription factor forkhead box C2 (FOXC2) and the clinical features of cervical cancer. A total of 66 patients with cervical cancer, 42 patients with cervical intraepithelial neoplasia (CIN) and 25 patients with cervical inflammation were enrolled. The positive expression rates and expression levels of mRNA of FOXC2, E-cadherin, N-cadherin, vascular endothelial growth factor (VEGF), stromal cell-derived factor-1 (SDF-1), Notch protein and lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1) in cervical tissues were detected using immunohistochemistry and RT-PCR. The positive expression rates and expression levels of mRNA of FOXC2, N-cadherin, VEGF, SDF-1, Notch and LYVE-1 in cervical cancer were significantly higher than those in CIN, and those in the inflammatory tissues were the lowest, while the positive expression rate of E-cadherin in cervical cancer was lower than that in CIN, and that in the inflammatory tissues was the highest (P<0.05). The positive expression rates of FOXC2, N-cadherin, VEGF, SDF-1, Notch and LYVE-1 in patients with cervical cancer [human papillomavirus (HPV) positive, squamous cell carcinoma, Stages III–IV, maximal diameter ≥3.8 cm and low differentiation] were increased, and the positive expression rate of E-cadherin was decreased (P<0.05). Correlation analysis revealed that FOXC2 was positively correlated with the positive expression rates of N-cadherin, VEGF, SDF-1, Notch and LYVE-1, and negatively correlated with E-cadherin (P<0.05). In conclusion, the high expression of FOXC2 is correlated with the HPV infection, pathological pattern, clinical stage, tumor diameter and differentiation grade of cervical cancer, which may be involved in the epithelial-mesenchymal transition, vascular and matrix formation, Notch signaling pathway and lymphangiogenesis.

MicroRNA Let-7g Directly Targets Forkhead Box C2 (FOXC2) to Modulate Bone Metastasis in Breast Cancer

Aberrantly expressed microRNAs have been implicated in lots of cancers. Reduced amounts of let-7g have been found in breast cancer tissues. The function of let-7g in bone metastasis of breast cancer remains poorly understood. This study is to explore the significance of let-7g and its novel target gene in bone metastasis of breast cancer.

The expression of let-7g or forkhead box C2 (FOXC2) was measured in human clinical breast cancer tissues with bone metastasis by using quantitative real-time Polymerase Chain Reaction (qRT-PCR). After transfection with let-7g or anti-let-7g in breast cancer cell linesMDA-MB-231or SK-BR3, qRT-PCR and Western blot were done to test the levels of let-7g and FOXC2. The effect of anti-let-7g and/ or FOXC2 RNA interference (RNAi) on cell migration in breast cancer cells was evaluated by using wound healing assay.

Clinically, qRT-PCR showed that FOXC2 levels were higher in breast cancer tissues with bone metastasis than those in their noncancerous counterparts. Let-7g was showed to be negatively correlated with FOXC2 in human breast cancer samples with bone metastasis. We found that enforced expression of let-7g reduced levels of FOXC2 protein by using Western blot in MDA-MB-231 cells. Conversely, anti-let-7g enhanced levels of FOXC2 in SK-BR3 cells. In terms of function, anti-let-7g accelerated migration of SK-BR3 cells. Interestingly, FOXC2 RNAi abrogated anti-let-7g-mediated migration in breast cancer cells. Thus, we conclude that let-7g suppresses cell migration through targeting FOXC2 in breast cancer. Our finding provides a new perspective for understanding the mechanism of bone metastasis in breast cancer.

Members of FOX family could be drug targets of cancers

FOX families play important roles in biological processes, including metabolism, development, differentiation, proliferation, apoptosis, migration, invasion and longevity. Here we are focusing on roles of FOX members in cancers, FOX members and drug resistance, FOX members and stem cells. Finally, FOX members as drug targets of cancer treatment were discussed. Future perspectives of FOXC1 research were described in the end.

The Emerging Roles of Forkhead Box (FOX) Proteins in Osteosarcoma

Osteosarcoma is the most common bone cancer primarily occurring in children and young adults. Over the past few years, the deregulation of a superfamily transcription factors, known as forkhead box (FOX) proteins, has been demonstrated to contribute to the pathogenesis of osteosarcoma. Molecular mechanism studies have demonstrated that FOX family proteins participate in a variety of signaling pathways and that their expression can be regulated by multiple factors. The dysfunction of FOX genes can alter osteosarcoma cell differentiation, metastasis and progression. In this review, we summarized the evidence that FOX genes play direct or indirect roles in the development and progression of osteosarcoma, and evaluated the emerging role of FOX proteins as targets for therapeutic intervention.