Overexpression of FOXM1 is associated with metastases of nasopharyngeal carcinoma

GTSE1 promotes nasopharyngeal carcinoma proliferation and angiogenesis by upregulating STMN1

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a malignant tumor with poor survival rate. G2 and S phase-expressed-1 (GTSE1) takes part in the progression of diverse tumors as an oncogene, but its role and potential mechanism in NPC remain unknown.

METHODS

The GTSE1 expression was analyzed by western blot in NPC tissues and cells. Knock-down experiments were conducted to determine the function of GTSE1 in NPC by cell counting kit-8, the 5-ethynyl-2'-deoxyuridine (EdU) incorporation experiment, cell scratch wound-healing experiment, transwell assays, tube forming experiment and western blot. In addition, the in vivo role of GTSE1 was addressed in tumor-bearing mice.

RESULTS

The expression of was increased in NPC. Silencing of GTSE1 suppressed cell viability, the percent of EdU positive cells, and the number of invasion cells and tubes, but enhanced the scratch ratio in NPC cells. Mechanically, downregulation of GTSE1 decreased the expressions of FOXM1 and STMN1, which were restored with the upregulation of FOXM1. Increased expression of STMN1 reversed the effects of the GTSE1 silencing on proliferation, migration, invasion and angiogenesis of NPC cells. Furthermore, knockdown of GTSE1 repressed the tumor volume and tumor weight of xenografted mice.

CONCLUSION

GTSE1 was highly expressed in NPC, and silencing of GTSE1 ameliorated the malignant processes of NPC cells by upregulating STMN1, suggesting a possible therapeutical target for NPC.

FOXM1 Participates in Scleral Remodeling in Myopia by Upregulating APOA1 Expression Through METTL3/YTHDF2

Purpose

Apolipoprotein A1 (APOA1) is a potential crucial protein and treatment goal for pathological myopia in humans. This study set out to discover the function of APOA1 in scleral remodeling in myopia and its underlying mechanisms.

Methods

A myopic cell model was induced using hypoxia. Following loss- and gain-of function experiments, the expression of the myofibroblast transdifferentiation-related and collagen production-related factors Forkhead box M1 (FOXM1), APOA1, and methyltransferase-like 3 (METTL3) in the myopic cell model was examined by quantitative reverse transcription polymerase chain reaction (RT-qPCR) and western blotting. The proliferation and apoptosis were determined by Cell Counting Kit-8 assay and flow cytometry, respectively. Chromatin immunoprecipitation (ChIP) was employed to examine FOXM1 enrichment in the METTL3 promoter, methylated RNA immunoprecipitation (Me-RIP) to examine the N6-methyladenosine (m6A) modification level of APOA1, and photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation (PAR-CLIP) to examine the binding between METTL3 and APOA1.

Results

Hypoxia-induced human scleral fibroblasts (HSFs) had high APOA1 and FOXM1 expression and low METTL3 expression. FOXM1 knockdown elevated METTL3 expression and downregulated APOA1 expression. FOXM1 was enriched in METTL3 promoter. APOA1 or FOXM1 knockdown or METTL3 overexpression reversed the hypoxia-induced elevation in vinculin, paxillin, and α-smooth muscle actin (α-SMA) levels and apoptosis and the reduction in collagen, type I, alpha 1 (COL1A1) level and cell proliferation in HSFs. METTL3 or YTH N6-methyladenosine RNA binding protein F2 (YTHDF2) knockdown or APOA1 overexpression reversed the impacts of FOXM1 knockdown on vinculin, paxillin, α-SMA, and COL1A1 expression and cell proliferation and apoptosis.

Conclusions

FOXM1 elevated the m6A methylation level of APOA1 by repressing METTL3 transcription and enhanced APOA1 mRNA stability and transcription by reducing the YTHDF2-recognized m6A methylated transcripts.

The role of fascin-1 in the pathogenesis, diagnosis and management of respiratory related cancers

Human cancer statistics report that respiratory related cancers such as lung, laryngeal, oral and nasopharyngeal cancers account for a large proportion of tumors, and tumor metastasis remains the major reason for patient death. The metastasis of tumor cells requires actin cytoskeleton remodeling, in which fascin-1 plays an important role. Fascin-1 can cross-link F-actin microfilaments into bundles and form finger-like cell protrusions. Some studies have shown that fascin-1 is overexpressed in human tumors and is associated with tumor growth, migration and invasion. The role of fascin-1 in respiratory related cancers is not very clear. The main purpose of this study was to provide an updated literature review on the role of fascin-1 in the pathogenesis, diagnosis and management of respiratory related cancers. These studies suggested that fascin-1 can serve as an emerging biomarker and potential therapeutic target, and has attracted widespread attention.

The bacterial thiopeptide thiostrepton. An update of its mode of action, pharmacological properties and applications

The bacterial thiopeptide thiostrepton (TS) is used as a veterinary medicine to treat bacterial infections. TS is a protein translation inhibitor, essentially active against Gram-positive bacteria and some Gram-negative bacteria. In procaryotes, TS abrogates binding of GTPase elongation factors to the 70S ribosome, by altering the structure of rRNA-L11 protein complexes. TS exerts also antimalarial effects by disrupting protein synthesis in the apicoplast genome of Plasmodium falciparum. Interestingly, the drug targets both the infectious pathogen (bacteria or parasite) and host cell, by inducing endoplasmic reticulum stress-mediated autophagy which contributes to enhance the host cell defense. In addition, TS has been characterized as a potent chemical inhibitor of the oncogenic transcription factor FoxM1, frequently overexpressed in cancers or other diseases. The capacity of TS to crosslink FoxM1, and a few other proteins such as peroxiredoxin 3 (PRX3) and the 19S proteasome, contributes to the anticancer effects of the thiopeptide. The anticancer activities of TS evidenced using diverse tumor cell lines, in vivo models and drug combinations are reviewed here, together with the implicated targets and mechanisms. The difficulty to formulate TS is a drag on the pharmaceutical development of the natural product. However, the design of hemisynthetic analogues and the use of micellar drug delivery systems should facilitate a broader utilization of the compound in human and veterinary medicines. This review shed light on the many pharmacological properties of TS, with the objective to promote its use as a pharmacological tool and medicinal product.

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.

SPAG5 promotes osteosarcoma metastasis via activation of FOXM1/MMP2 axis

Osteosarcoma (OS) is a primary malignancy of bone with a tendency to metastasize early. An understanding of the pathways that regulate OS metastasis is required for the design of novel treatment approaches. Sperm-associated antigen 5 (SPAG5) is upregulated and functions as a potential tumor promoter in diverse human cancers, but has yet to be investigated in the OS. In the present study, results showed that SPAG5 expression is upregulated in OS tissues, and SPAG5 overexpression is obviously associated with the malignant phenotype and poor survival in patients with OS. Multivariate analyses also revealed that SPAG5 overexpression is an independent prognostic factor for poor outcome of patients with OS. The functional assay indicated that SPAG5 silencing significantly inhibits the invasion and migration of OS cells in vitro. Additionally, knockdown of SPAG5 in OS cells suppresses lung metastasis in vivo. Further, we also found that SPAG5 silencing inhibits the epithelial-mesenchymal transition (EMT) process of OS cells. Moreover, our results indicated that SPAG5 promotes OS metastasis by increasing matrix metalloproteinase-2 (MMP2) expression, and demonstrated that MMP2 is crucial for the pro-metastasis role of SPAG5 in OS cells. Mechanistically, we identified that SPAG5 regulates MMP2 expression by modulating FOXM1 (Forkhead box M1) degradation to enhance the protein stability of FOXM1. Collectively, these findings describe the effects of SPAG5-FOXM1-MMP2 axis in the regulation of OS cell migration and metastasis formation. We provide a novel evidence that SPAG5 may serve as a prognostic indicator and potential therapeutic target for patients with osteosarcoma.

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

Background

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

Methods

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

Results

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

Conclusion

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

Effects and mechanism of siomycin A on the growth and apoptosis of MiaPaCa-2 cancer cells

Siomycin A is a type of thiopeptide antibiotic that is isolated from the fermentation products of an endophytic actinomycin, which is derived from the medicinal plant Acanthopanax senticosus. The present study investigated whether siomycin A has antitumor effects in vitro on a variety of cell lines. A Cell Counting Kit-8 assay was performed to detect the effects of siomycin A on cell viability; morphological changes in the MiaPaCa-2 cell line were analyzed using an inverted phase contrast microscope. A Transwell migration assay was applied to detect cell migration ability. The cytoskeleton was observed by laser confocal microscopy, and apoptosis was detected using flow cytometry. A western blot assay was used to detect the expression of matrix metalloproteinase (MMP)-2, MMP-9 and α-tubulin. The results revealed that siomycin A inhibited the proliferation of human tumor cell lines of different origins. As the concentration of siomycin A increased, the cell density decreased gradually and cells exhibited a morphological change from spindle to spherical shape. Furthermore, 24 h after administration, the cell migration ability was inhibited. The cytoskeleton complexity and morphological changes were increased after administration of siomycin A. The percentage of apoptotic cells was significantly increased and the expression levels of MMP-2, MMP-9 and α-tubulin were downregulated by siomycin A. Therefore, siomycin A was determined to effectively inhibit the proliferative ability of a variety of human tumor cell lines. Siomycin A was also determined to affect the cytoskeleton of tumor cells by downregulating the expression of α-tubulin protein.

Identification of candidate genes of nasopharyngeal carcinoma by bioinformatical analysis

OBJECTIVE

This study aimed to identify candidate genes as potential biomarkers in nasopharyngeal carcinoma (NPC) by bioinformatical analysis.

METHODS

Three microarray datasets: GSE32906, GSE15170, GSE53819 were download from public database and analyzed to identify the differentially expressed genes (DEGs) between NPC and normal samples. Functional and pathway enrichment analysis of the DEGs were performed. Protein-protein interaction network and gene-transcription factor regulatory network of DEGs were constructed. And the expression of hub genes in NPC was also validated based on the public database.

RESULTS

A total of 16 up-regulated and 27 down-regulated genes were screened out from the microarray datasets. Functional and pathway enrichment analysis showed that DEGs were mostly enriched in positive regulation of angiogenesis, mesenchymal cell proliferation, cell surface and DNA binding, ECM-receptor interaction pathway, PI3K-Akt signaling pathway, and pathways in cancer. Five hub genes JUN, VEGFA, FOXM1, MYB, and WNT5A were identified from the protein-protein interaction network. Subsequently, the hub gene-transcription factor regulatory network revealed that STAT3, MYC, SOX2, RUNX2 present key relations with hub genes. The expression of these five hub genes were also validated to be differentially expressed among NPC and normal samples.

CONCLUSIONS

The current study indicated that the hub DEGs JUN, VEGFA, FOXM1, MYB, and WNT5A we identified might be potential therapeutic biomarkers of NPC.

Downregulation of FoxM1 sensitizes nasopharyngeal carcinoma cells to cisplatin via inhibition of MRN-ATM-mediated DNA repair

Chemoresistance is the primary obstacle in the treatment of locally advanced and metastatic nasopharyngeal carcinoma (NPC). Recent evidence suggests that the transcription factor forkhead box M1 (FoxM1) is involved in chemoresistance. Our group previously confirmed that FoxM1 is overexpressed in NPC. In this study, we investigated the role of FoxM1 in cisplatin resistance of the cell lines 5–8F and HONE-1 and explored its possible mechanism. Our results showed that FoxM1 and NBS1 were both overexpressed in NPC tissues based on data from the GSE cohort (GSE12452). Then, we measured FoxM1 levels in NPC cells and found FoxM1 was overexpressed in NPC cell lines and could be stimulated by cisplatin. MTT and clonogenic assays, flow cytometry, γH2AX immunofluorescence, qRT-PCR, and western blotting revealed that downregulation of FoxM1 sensitized NPC cells to cisplatin and reduced the repair of cisplatin-induced DNA double-strand breaks via inhibition of the MRN (MRE11-RAD50-NBS1)-ATM axis, which might be related to the ability of FoxM1 to regulate NBS1. Subsequently, we demonstrated that enhanced sensitivity of FoxM1 knockdown cells could be reduced by overexpression of NBS1. Taken together, our data demonstrate that downregulation of FoxM1 could improve the sensitivity of NPC cells to cisplatin through inhibition of MRN-ATM-mediated DNA repair, which could be related to FoxM1-dependent regulation of NBS1.

Investigation of differentially expressed genes in nasopharyngeal carcinoma by integrated bioinformatics analysis

Nasopharyngeal carcinoma (NPC) is a common malignancy of the head and neck. The aim of the present study was to conduct an integrated bioinformatics analysis of differentially expressed genes (DEGs) and to explore the molecular mechanisms of NPC. Two profiling datasets, GSE12452 and GSE34573, were downloaded from the Gene Expression Omnibus database and included 44 NPC specimens and 13 normal nasopharyngeal tissues. R software was used to identify the DEGs between NPC and normal nasopharyngeal tissues. Distributions of DEGs in chromosomes were explored based on the annotation file and the CYTOBAND database of DAVID. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were applied. Additionally, a protein-protein interaction (PPI) network, constructed using the STRING database and visualized by Cytoscape, was used to identify hub genes, key modules and important transcription factors (TFs). A total of 906 DEGs were identified; 434 (47.90%) DEGs were upregulated and 472 (52.10%) were downregulated. The DEGs were demonstrated to be enriched in chromosome 7p15-p14, 2q31, 1q21-q22, 1q21, 4q21 and 1p31-p22. DEGs were mainly enriched for the following GO terms: 'Cilium movement', 'microtubule bundle formation' and 'axoneme assembly'. KEGG pathway enrichment analysis revealed that pathways for 'cell cycle', 'DNA replication', 'interleukin-17 signaling', 'amoebiasis' and 'glutathione metabolism' were enriched. In addition, a PPI network comprising 867 nodes and 1,241 edges was constructed. Finally, five hub genes (aurora kinase A, cell division cycle 6, mitotic arrest deficient 2-like 1, DNA topoisomerase 2α and TPX2 microtubule nucleation factor), 8 modules, and 14 TFs were identified. Modules analysis revealed that cyclin-dependent kinase 1 and exportin 1 were involved in the pathway of Epstein-Barr virus infection. In summary, the hub genes, key modules and TFs identified in this study may promote our understanding of the pathogenesis of NPC and require further in-depth investigation.

Downregulation of FoxM1 sensitizes nasopharyngeal carcinoma cells to cisplatin via inhibition of MRN-ATM-mediated DNA repair

Chemoresistance is the primary obstacle in the treatment of locally advanced and metastatic nasopharyngeal carcinoma (NPC). Recent evidence suggests that the transcription factor forkhead box M1 (FoxM1) is involved in chemoresistance. Our group previously confirmed that FoxM1 is overexpressed in NPC. In this study, we investigated the role of FoxM1 in cisplatin resistance of the cell lines 5-8F and HONE-1 and explored its possible mechanism. Our results showed that FoxM1 and NBS1 were both overexpressed in NPC tissues based on data from the GSE cohort (GSE12452). Then, we measured FoxM1 levels in NPC cells and found FoxM1 was overexpressed in NPC cell lines and could be stimulated by cisplatin. MTT and clonogenic assays, flow cytometry, γH2AX immunofluorescence, qRT-PCR, and western blotting revealed that downregulation of FoxM1 sensitized NPC cells to cisplatin and reduced the repair of cisplatin-induced DNA double-strand breaks via inhibition of the MRN (MRE11-RAD50-NBS1)-ATM axis, which might be related to the ability of FoxM1 to regulate NBS1. Subsequently, we demonstrated that enhanced sensitivity of FoxM1 knockdown cells could be reduced by overexpression of NBS1. Taken together, our data demonstrate that downregulation of FoxM1 could improve the sensitivity of NPC cells to cisplatin through inhibition of MRN-ATM-mediated DNA repair, which could be related to FoxM1-dependent regulation of NBS1. [BMB Reports 2019; 52(3): 208-213].

FAST1 promotes the migration and invasion of colorectal cancer cells

BACKGROUND

The forkhead activin signal transducer 1 (FAST1) is involved in several oncogenic signaling pathways and its abnormal expression has been discovered in some cancers. Yet the role of FAST1 in colorectal cancer (CRC) remains largely unclear. Therefore, the goal of this study was to explore the function of FAST1 in CRC.

METHODS

In this study, we analyzed FAST1 expression and its relationship with clinicopathological parameters and prognostic significance in CRC via immunohistochemistry analysis. The effects and mechanisms of FAST1 on cell proliferation, migration and invasion were explored in vitro and in vivo.

RESULTS

We found that increased FAST1 as an independent prognostic factor was positively associated with TNM stage and pathological grade in CRC. FAST1 overexpression promoted the CRC cell proliferation, migration and invasion in vivo. Furthermore, mechanistic studies implicated that FAST1 enhanced the pulmonary metastasis of CRC cells through down-regulating E-cadherin levels.

CONCLUSIONS

In summary, FAST1 was significantly associated with CRC progression and could serve as an independent prognostic factor. FAST1 may be potential therapeutic target for CRC patients.

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.

FoxM1 is an independent poor prognostic marker and therapeutic target for advanced Middle Eastern breast cancer

Breast cancer (BC) is the most common cause of cancer-related death in females in Saudi Arabia. BC in Saudi women tend to behave more aggressively than breast cancer in the West. Therefore, identification of new molecular targets and treatment strategies are highly warranted to improve patient outcome. FoxM1 has been shown to play a critical role in pathogenesis of various malignancies. In this study, we explored the prevalence and clinical implication of FoxM1 overexpression in Saudi breast cancer. FoxM1 protein overexpression was seen in 79% (770/975) of BC tissues and was associated with aggressive clinical parameters such as younger age (< 30 yrs) (p = 0.0172), high grade (p < 0.0001), mucinous histology (p < 0.0001) and triple negative phenotype (p < 0.0001). Overexpression of FoxM1 was significantly associated with activated AKT (p < 0.0001), Ki67 expression (p < 0.0001), VEGF (p < 0.0001), MMP-9 (p < 0.0001), XIAP (p < 0.0001) and Bcl-xL (p = 0.0300). Importantly, FoxM1 overexpression is found to be an independent prognostic marker in multivariate analysis in advanced stage (Stage III and IV) breast cancer (p = 0.0298). In vitro data using BC cell lines showed that down-regulation of FoxM1 using specific inhibitor, thiostrepton or siRNA inhibited cell migration, invasion and angiogenesis. In addition, treatment of BC cell lines with thiostrepton resulted in inhibition of proliferation and induction of apoptosis in a dose-dependent manner. In vivo, thiostrepton treatment regressed MDA-MB-231 cells generated xenografts via down-regulation of FoxM1 and its downstream targets. Our results suggest that FoxM1 may be a potential therapeutic target for the treatment of aggressive breast cancers.

UBE2C Is a Transcriptional Target of the Cell Cycle Regulator FOXM1

FOXM1 (forkhead box protein M1) is a transcription factor that participates in all stages of tumor development, mainly through the control of cell cycle and proliferation, regulating the expression of genes involved in G1/S and G2/M transition and M phase progression. The ubiquitin conjugating enzyme E2 (UBE2C) is a member of the anaphase promoting complex/cyclosome, promoting the degradation of several target proteins along cell cycle progression, during metaphase/anaphase transition. FOXM1 and UBE2C have been found overexpressed in a wide range of different solid tumors. Therefore, the aim of this study was to investigate whether UBE2C is a transcriptional target of FOXM1, using esophageal squamous cell carcinoma (ESCC) as a model, in addition to several cancer-deposited data. Our results show that FOXM1 and UBE2C expression present a positive correlation in normal tissues and in 25 distinct tumor types, including ESCC, where these genes are overexpressed. Moreover, FOXM1 binds to UBE2C promoter region in ESCC cell line and transcriptionally activates it, leading to UBE2C upregulation. In conclusion, this study provides evidences that FOXM1 transcriptionally regulates UBE2C expression in ESCC and their deregulation may be a general phenomenon in human neoplasias.

FoxM1 Promotes Cell Proliferation, Invasion, and Stem Cell Properties in Nasopharyngeal Carcinoma

Background: The self-renewal and tumourigenicity of FoxM1 in nasopharyngeal carcinoma (NPC) remain largely unknown. In this study, we attempt to investigate the self-renewal and tumourigenicity of FoxM1 and its clinical significance in nasopharyngeal carcinoma (NPC). Methods: Several assays including cell counting Kit-8 (CCK-8) assays, colony formation, flow cytometry, immunofluorescence, tumor spheres, and mice model were used to detect the biological function of FoxM1 in NPC. The association between FoxM1 and clinical pathological features, and stem cell markers was analyzed using immunohistochemistry. Results: High expression of FoxM1 was prominently present in the T4 stages, cancer cells migrating into the stroma and vasculature. Overexpression of FoxM1 enhanced tumor proliferation, cell cycle progression, migration and stress fibers formation in vitro. In NPC tissues, FoxM1 correlated significantly with stem cells-related clinical pathological features including late clinical stage, tumor recurrence and distant metastasis. Meanwhile, FoxM1 linked closely with the expression levels of stem cell markers including Nanog, Sox2, and OCT4 in tumor samples, and also promoted the expression of these stemness-related genes in vitro. Moreover, FoxM1 conferred the self-renewal properties of cancer cells by increasing side populations (SP) cells and formed larger and more tumor spheres. Importantly, FoxM1 enhanced the ability of tumourigenicity of NPC cell lines in mice xenograft. Conclusions: We demonstrate that FoxM1 greatly induces cancer progression and cancer stem cell (CSC) features in NPC.

Clinical and biological significance of HAX-1 overexpression in nasopharyngeal carcinoma

HS1-associated protein X-1 (HAX-1) is an important marker in many types of cancers and contributes to cancer progression and metastasis. We examined the expression of HAX-1 in nasopharyngeal carcinoma (NPC) and experimentally manipulated its expression. We observed that HAX-1 expression is elevated in NPC and is correlated with lymph node metastasis, M classification, clinical stage, and poor prognosis. In addition, overexpression of HAX-1 promoted NPC proliferation both in vitro and in vivo. Exosomes are potential carriers of pro-tumorigenic factors that participate in oncogenesis. We found that NPC-derived exosomes are enriched in HAX-1 and accelerate NPC tumor growth and angiogenesis in vitro and in vivo. Furthermore, we demonstrated that oncogenic HAX-1 facilitates the growth of NPC when it is transferred via exosomes to recipient human umbilical vein endothelial cells (HUVECs). Oncogenic HAX-1 also increases the proliferation, migration, and angiogenic activity of HUVECs. Our findings provide unique insight into the pathogenesis of NPC and underscore the need to explore novel therapeutic targets such as HAX-1 to improve NPC treatment.

Secretory leukocyte protease inhibitor (SLPI) as a potential target for inhibiting metastasis of triple-negative breast cancers

SLPI has been implicated in the progression and metastasis of certain cancers. However, the effects of SLPI seem to be tumor-specific and the mechanisms remain poorly defined. Here, we demonstrate that highly metastatic, triple-negative breast cancer (TNBC) 4T1 cells secreted more SLPI compared to their non-metastatic counterparts. Furthermore, SLPI secretion directly correlated with spontaneous lung metastasis from 4T1 tumors orthotopically implanted in mice. Consistent with our experimental results, we also found that higher SLPI expression levels correlate with worse clinical outcome in basal/TNBC patients. Using high-throughput screening we identified a novel compound, C74, which significantly inhibits SLPI secretion. C74 administration in our mouse model slows the growth of primary 4T1 tumors and inhibits their dissemination to the lung. We also discovered that SLPI physically interacts with the retinoblastoma tumor suppressor protein (Rb) and releases FoxM1 from the Rb-FoxM1 complex, which may activate FoxM1 target genes involved in breast cancer metastasis.

FoxM1 overexpression promotes cell proliferation and migration and inhibits apoptosis in hypopharyngeal squamous cell carcinoma resulting in poor clinical prognosis

Forkhead box M1 (FoxM1), a member of the Fox family of transcriptional factors, is involved in the development of various human malignancies. However, the expression level of FoxM1 and its functional role in hypopharyngeal squamous cell carcinoma (HSCC) remained unclear to date. The aim of the present study was to investigate the FoxM1 expression in 63 HSCC and 20 adjacent normal tissues, as well as to evaluate its association with the clinicopathological parameters and its diagnostic value in HSCC. To further explore the biological function of FoxM1 in vitro, siRNAs were used to knockdown the expression of FoxM1 in the HSCC cell line Fadu. The results revealed that FoxM1 protein was highly expressed in HSCC tissues and that its high expression was closely associated with HSCC tumor differentiation (P=0.004), tumor size (P=0.002), clinical stage (P=0.001), lymph node metastasis (P=0.002), treatment (P=0.045) and expression of the proliferation marker Ki-67 (P<0.001). Additionally, the elevated expression of FoxM1 in HSCC patients consistently predicted a poor survival time. Knockdown of FoxM1 expression blocked Fadu cell proliferation and promoted apoptosis, and also led to the down-regulation of cyclin A1 expression. Furthermore, decreased expression of FoxM1 markedly impeded cell migration and reversed the epithelial-mesenchymal transition phenotype, as indicated by decreased expression of vimentin and increased expression of E-cadherin in Fadu cells. These results indicate that FoxM1 may act as an oncogene and serve as a therapeutic target against malignant progression in HSCC.

Lovastatin Inhibits Cancer Stem Cells and Sensitizes to Chemo- and Photodynamic Therapy in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus-associated malignancy occurring at high incidence in Southeast Asia and southern China. In spite of the good response to radio- and chemo-therapy at the early stage, resistance and recurrence develop in NPC patients in the advanced setting. Cancer stem cells (CSCs) play an important role in drug resistance and cancer recurrence. Here we report that lovastatin, a natural compound and a lipophilic statin that has already been used in the clinic to treat hypercholesterolemia, inhibited the CSC properties and induced apoptosis and cell cycle arrest in sphere-forming cells derived from the 5-8F and 6-10B NPC cell lines. Furthermore, lovastatin conferred enhanced sensitivity to the chemotherapeutic and photodynamic agents in NPC CSCs. Together our findings suggest that targeting CSCs by lovastatin in combination with routine chemotherapeutic drugs or photodynamic therapy might be a promising approach to the treatment of NPC.

FOXM1 participates in PLK1-regulated cell cycle progression in renal cell cancer cells

The regulation of entry into and progression through mitosis is important for cell proliferation. Polo-like kinase 1 (PLK1) is involved in multiple stages of mitosis. Forkhead box protein M1 (FOXM1) has multiple functions in tumorigenesis and, in elevated levels, is frequently associated with cancer progression. The present study reports that FOXM1, a substrate of PLK1, controls the transcription mechanism that mediates the PLK1-dependent regulation of the cell cycle. The present study investigated the expression of PLK1 and FOXM1 in the clear renal cell carcinoma 769-P and ACHN cell lines, and indicated that the expression of PLK1 and FOXM1 are correlated in human renal cell cancer cell lines and that the suppression of PLK1 may decrease the expression of FOXM1. The knockdown of FOXM1 or PLK1 in renal cell cancer cell lines caused cell cycle progression to be blocked. As a result, the present study indicated the involvement of FOXM1 in PLK1-regulated cell cycle progression.

Expression of Aurora-B and FOXM1 predict poor survival in patients with nasopharyngeal carcinoma

PURPOSE

The purpose of this work was to investigate the relationship between Aurora-B, FOXM1, and clinical outcomes in patients with nasopharyngeal carcinoma (NPC) who were treated with a combination of induction chemotherapy and radiotherapy.

PATIENTS AND METHODS

The expression of Aurora-B and FOXM1 were investigated by immunohistochemistry using a tissue microarray (TMA) containing samples from 166 NPC patients who were treated with cisplatin (DDP) + fluorouracil (5-FU) induction chemotherapy and radiotherapy between 1999 and 2005. The relationship of Aurora-B, FOXM1, and survival of these NPC patients was analyzed.

RESULTS

Informative TMA results were obtained in 91 tumor cases for Aurora-B and 93 tumor cases for FOXM1. The 8-year failure-free survival rate (FFS) for the Aurora-B-negative and Aurora-B-positive group was 65.6 and 37.3%, respectively (p = 0.024), and the 8-year distant FFS (D-FFS) rate was 65.6 and 41.5%, respectively (p = 0.047). The 8-year overall survival (OS) in the FOXM1-negative group was moderately higher than in the FOXM1-positive group (58.4 vs 39.1%, p = 0.081). Cox regression analysis revealed that for FFS, Aurora-B expression was a significant prognostic factor (p = 0.025), while for D-FFS, Aurora-B expression was a marginally significant prognostic factor (p = 0.056). When FOXM1 expression was analyzed, the Cox regression analyses showed that FOXM1 expression was a marginally significant prognostic factor (p = 0.056) for OS. Correlation analysis showed that Aurora-B and FOXM1 expression had no significant correlation.

CONCLUSION

Aurora-B and FOXM1 were both adverse prognostic markers for NPC patients treated with chemoradiotherapy. However, the two markers had no significant correlation.