Overexpression of Forkhead Box M1 transcription factor and nuclear factor-κB in laryngeal squamous cell carcinoma: a potential indicator for poor prognosis

Hsa_circ_0042823 accelerates cancer progression via miR-877-5p/FOXM1 axis in laryngeal squamous cell carcinoma

BACKGROUND

Laryngeal squamous cell carcinoma (LSCC) is a common malignant tumour of the head and neck. Our previous study reveals that the circular RNA (circRNA) hsa_circ_0042823 is abnormally expressed in LSCC, suggesting that hsa_circ_0042823 is closely associated with LSCC. Here, we attempted to explore the molecular mechanism of hsa_circ_0042823 in LSCC.

METHODS

Quantitative real-time PCR and western blot were performed to assess the expression of gene and protein in human laryngeal carcinoma cells, TU212 and TU686. MTT and transwell assays were performed to examine cell proliferation, migration and invasion. The relationship among hsa_circ_0042823, miR-877-5p and forkhead box M1 (FOXM1) was verified by luciferase reporter assay. Finally, we constructed a subcutaneous tumour mouse model to analyse in vivo growth of LSCC cells following knockdown of hsa_circ_0042823.

RESULTS

Compared with normal human bronchial epithelial cells (HBECs), hsa_circ_0042823 was highly expressed in the LSCC cell lines (AMC-HN-8 and TU686). Further studies demonstrated that hsa_circ_0042823 interacted with miR-877-5p, and FOXM1 was the target of miR-877-5p. Hsa_circ_0042823 promoted the expression of FOXM1 via its ceRNA activity on miR-877-5p. Hsa_circ_0042823 overexpression promoted proliferation, migration and invasion of AMC-HN-8 cells through regulating miR-877-5p/FOXM1 axis. Additionally, inhibition of hsa_circ_0042823 inhibited growth of LSCC in vivo via miR-877-5p/FOXM1 axis.

CONCLUSIONS

Hsa_circ_0042823/miR-877-5p/FOXM1 axis participates in the progression of LSCC. This work demonstrates that hsa_circ_0042823 accelerates cancer progression by regulating miR-877-5p/FOXM1 axis in LSCC. Therefore, this study may provide new insights into the pathogenesis of LSCC.KEY MESSAGESHsa_circ_0042823 promotes FOXM1 expression by sponging miR-877-5p.Hsa_circ_0042823 promotes proliferation, migration, invasion of LSCC cells.Hsa_circ_0042823 knockdown inhibits tumour growth of LSCC via miR-877-5p/FOXM1 axis.

Curcumin suppresses the proliferation of oral squamous cell carcinoma through a specificity protein 1/nuclear factor-κB-dependent pathway

Oral squamous cell carcinoma (OSCC) is the most common cancer of the oral cavity. Curcumin (Cur), a naturally derived compound, is reported to have broad-spectrum anticancer activity and is considered as an effective nuclear factor-κB (NF-κB) inhibitor. The present study aimed to clarify the detailed molecular mechanism though which Cur regulates NF-κB pathway activity in OSCC. The viability of HSC3 and CAL33 cells following treatment with Cur was determined using a Cell Counting Kit-8 assay. The protein and mRNA expression of specificity protein 1 (Sp1), p65 and heat shock factor 1 (HSF1) was determined by western blotting and reverse transcription-quantitative PCR analysis, respectively. The NF-κB activity was measured by Dual-Luciferase reporter assay. Short hairpin RNA targeting Sp1 or control RNA was transfected into HSC3 cells using X-treme GENE HP DNA Transfection System. Colony formation assays were performed using crystal violet staining. The results demonstrated that Cur significantly inhibited the viability and colony formation ability of HSC3 and CAL33 cells. In addition, Cur decreased the expression of Sp1, p65 and HSF1 by suppressing their transcription levels. Cur decreased NF-κB activity in OSCC cells, and Sp1 downregulation enhanced the effect of Cur. The findings from the present study suggested that Cur may inhibit the proliferation of OSCC cells via a Sp1/NF-κB-dependent mechanism.

The underlying molecular mechanism and identification of transcription factor markers for laryngeal squamous cell carcinoma

The screening and treatment of laryngeal squamous cell carcinoma (LSCC) still perplexes clinicians, making it necessary to explore new markers. To this end, this research examined the underlying molecular mechanism of LSCC based on high-throughput datasets (n = 249) from multiple databases. It also identified transcription factors (TFs) independently associated with LSCC prognosis. Through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses, differential expression genes of LSCC were deemed relevant to the extracellular matrix and its related structures or pathways, suggesting that the extracellular matrix plays an important role in LSCC. At the same time, several hub genes that may also have important roles in LSCC were identified via protein–protein interaction analysis, including CDC45, TPX2, AURKA, KIF2C, NUF, MUC1, MUC7, MUC4, MUC15, and MUC21. Eight unreported LSCC prognostic TFs – BCAT1, CHD4, FOXA2, GATA6, HNF1A, HOXB13, MAFF, and TCF4 – were screened via Kaplan–Meier curves. Cox analysis determined for the first time that HOXB13 expression and gender were independently associated with LSCC prognosis. Compared to control tissues, elevated expression of HOXB13 was found in LSCC tissues (standardized mean difference = 0.44, 95% confidence interval [0.13–0.76]). HOXB13 expression also makes it feasible to screen LSCC from non-LSCC (area under the curve = 0.77), and HOXB13 may play an essential role in LSCC by regulating HOXB7. In conclusion, HOXB13 may be a novel marker for LSCC clinical screening and treatment.

TRIM6 promotes colorectal cancer cells proliferation and response to thiostrepton by TIS21/FoxM1

BACKGROUND

Tripartite motif-containing proteins (TRIM) play a crucial role in carcinogenesis. Little attention has been focused on the possible functions of TRIM6 on carcinogenesis.

METHODS

The expression levels of TRIM6 were assessed in colorectal cancer (CRC) samples. TRIM6 expression was knocked down in CRC cell lines, and subjected to Cell counting kit-8 (CCK-8), bromodeoxyuridine (BrdU) incorporation and cell cycle assays. Immunoprecipitation and proteomics analysis was performed to identify potential associated proteins of TRIM6.

RESULTS

TRIM6 expression was up-regulated in CRC samples and TRIM6 expression may be an independent prognostic marker for CRC. Knocking down TRIM6 expression suppressed CRC cell proliferation, induced cell cycle arrested at G2/M phase and increased sensitivity to 5-fluorouracil and oxaliplatin. TIS21, an anti-proliferative protein involved in the regulation of G2/M arrest, was identified as an interaction partner of TRIM6. Moreover, CRC cells with TRIM6 overexpression showed decreased TIS21 protein stability. TIS21 ubiquitination was increased in CRC cells overexpressing TRIM6, but not in those overexpressing TRIM6 E3 catalytic mutant (C15A). Further, Lys5 was essential for TRIM6 mediated TIS21 ubiquitination. TIS21 overexpression reversed the induced effects of TRIM6 overexpression on CRC cell proliferation, and the levels of forkhead box M1 (FoxM1), phosphorylated FoxM1, Cyclin B1 and c-Myc. Thiostrepton, a specific inhibitor for FoxM1, was less effective in anti-proliferative activity against CRC cells with lower level of TRIM6 in vitro and in vivo.

CONCLUSIONS

Our study suggests that TRIM6 promotes the progression of CRC via TIS21/FoxM1.

FOXM1 is a novel predictor of recurrence in patients with oral squamous cell carcinoma associated with an increase in epithelial‑mesenchymal transition

Although forkhead box protein M1 (FOXM1) is markedly upregulated in human premalignant and oral squamous cell carcinoma (OSCC) tissues and cultured cells, the association of FOXM1 expression with OSCC prognosis is not well understood. The present study investigated the possible association of FOXM1 expression in patients with OSCC with their clinicopathological characteristics and clinical outcomes. The expression of FOXM1 protein in OSCC tissues from 119 patients was evaluated by immunohistochemistry, and the results demonstrated that FOXM1 overexpression in patients with OSCC was associated with tumour recurrence and poor prognosis. To study the in vitro effects of FOXM1, its expression was decreased by small interfering RNA (siRNA) in OSCC cell lines, and FOXM1 knockdown decreased the proliferative, migratory and invasive capacities of cells. FOXM1 inhibition by siRNA gave rise to reduced expression of vimentin and increased expression of E‑cadherin. The present study reported FOXM1 as a novel predictor of tumour recurrence in patients with OSCC and its potential involvement in epithelial‑mesenchymal transition in OSCC cells.

Esophageal squamous cell carcinoma transcriptome reveals the effect of FOXM1 on patient outcome through novel PIK3R3 mediated activation of PI3K signaling pathway

Esophageal squamous cell carcinoma (ESCC) presents poor prognosis, and patients diagnosed with this tumor currently lack target treatments. Therefore, in order to identify potential targets for ESCC treatment, we carried out a transcriptome analysis with ESCC and paired nonmalignant surrounding mucosa samples, followed by a master regulator analysis, and further explored the role of the identified central regulatory genes through in vivo and in vitro assays. Among the transcription factors deregulated/enriched in ESCC, we focused on FOXM1 because of its involvement in the regulation of critical biological processes. A new transcriptome analysis performed with ESCC cell lineage TE-1 showed that the modulation of FOXM1 expression resulted in PIK3R3 expression changes, whereas chromatin immunoprecipitation assay revealed that FOXM1 was capable of binding onto PIK3R3 promoter, thus demonstrating that PIK3R3 is a new FOXM1 target. Furthermore, FOXM1 overexpression resulted in the activation of PIK3/AKT signaling pathway through PIK3R3-mediated AKT phosphorylation. Finally, the analysis of the clinic-pathological data of ESCC patients revealed that overexpression of both FOXM1 and PIK3R3 was associated with poor prognosis, but only the latter was an independent prognosis factor for ESCC patients. In conclusion, our results show that FOXM1 seems to play a central role in ESCC carcinogenesis by upregulating many oncogenes found overexpressed in this tumor. Furthermore, PIK3R3 is a novel FOXM1 target that triggers the activation of the PI3K/AKT pathway in ESCC cells.

Prognostic value of FOXM1 in solid tumors: a systematic review and meta-analysis

Accumulated studies have provided controversial evidences of the association between Forkhead Box M1 (FOXM1) expression and survival of human solid tumors. To address this inconsistency, we performed a meta-analysis with 23 studies identified from PubMed and Medline. We found elevated FOXM1-protein expression was significantly associated with worse 3-year overall survival (OS) (OR = 3.30, 95% CI = 2.56 to 4.25, P < 0.00001) 5-year OS (OR =3.35, 95% CI = 2.64 to 4.26, P < 0.00001) and 10-year OS (OR = 5.24, 95% CI = 2.61 to 10.52, P < 0.00001) of human solid tumors. Similar results were observed when disease free survival (DFS) were analyzed. Subgroup analysis showed that FOXM1 overexpression was associated with poor prognosis of colorectal cancer, gastric cancer, hepatic cancer, lung cancer and ovarian cancer. High expression level of FOXM1 was also associated with advanced tumor stage. In conclusion, elevated FOXM1 expression is associated with poor survival in most solid tumors. FOXM1 is a potential biomarker for prognosis prediction and a promising therapeutic target in human solid tumors.

A link between RelB expression and tumor progression in laryngeal cancer

Laryngeal cancer is a frequent malignancy originating from the squamous vocal epithelium in a multi-stage fashion in response to environmental carcinogens. Although most cases can be cured by surgery and/or radiotherapy, advanced and relapsing disease is common, and biomarkers of such dismal cases are urgently needed. The cancer genome of laryngeal cancers was recently shown to feature a signature of aberrant nuclear factor (NF)-κB activation, but this finding has not been clinically exploited. We analyzed primary tumor samples of 96 well-documented and longitudinally followed patients covering the whole spectrum of laryngeal neoplasia, including 21 patients with benign laryngeal diseases, 15 patients with dysplasia, 43 patients with early-stage carcinoma, and 17 patients with locally advanced carcinoma, for immunoreactivity of RelA, RelB, P50, and P52/P100, the main NF-κB subunits that activate transcription. Results were cross-examined with indices of tumor progression and survival. Interestingly, RelB expression increased with tumor stage, grade, and local extent. Moreover, patients displaying high RelB immunoreactivity exhibited statistically significantly poorer survival compared with patients featuring low levels of RelB expression (P = 0.018 by log-rank test). Using Cox regression analyses and tumor stage, local extent, grade and RelA/RelB immunoreactivity, we develop a new score that can independently predict survival of patients with laryngeal cancer. Hence we provide a simple and affordable NF-κB-based test to predict prognosis in laryngeal cancer.

NF-κB Expression and Outcomes in Solid Tumors: A Systematic Review and Meta-Analysis

Nuclear factor-kappaB (NF-κB) is a key inflammatory transcription factor expressed frequently in tumors. Numerous studies have investigated the correlation between NF-κB expression and prognosis in solid tumors, but the conclusions are still in contradiction. Here, we conduct a meta-analysis to explore the overall association of NF-κB overexpression and survival in human solid tumors. Pubmed and EBSCO databases were searched for studies evaluating expression of NF-κB (as measured by immunohistochemistry) and overall survival (OS) and disease-free survival (DFS) in solid tumors. Published data were extracted and computed into odds ratios (ORs) for death at 3, 5, and 10 years. Data were pooled using the Mantel-Haenszel random-effect model. All statistical tests were two-sided. Forty-four studies with a total of 4418 patients were included in this meta-analysis. NF-κB overexpression was associated with worse OS at 3 years (OR = 3.40, 95% confidence interval [CI]  = 2.41-4.79, P < 0.00001), 5 years (OR = 2.72, 95% CI = 1.92-3.85, P < 0.00001), and 10 years (OR = 2.63, 95% CI =  .34-5.16, P = 0.005) of solid tumors. Results for 3- and 5-year DFS were similar. NF-κB expression was associated with poor 3-year OS in both Tumor, Lymph Node, Metastasis stage I-II (OR = 9.11, 95% CI = 2.90-28.68, P = 0.0002) and III-IV (OR = 2.59, 95% CI = 1.61-4.15, P < 0.0001). There is no correlation between cellular localization of NF-kB overexpression and OS of solid tumors. Among the tumor types, NF-κB was associated with worse 3 year-OS of colorectal cancer (OR = 2.70, 95% CI = 1.64-4.46, P < 0.0001), esophageal carcinoma (OR = 6.00, 95% CI = 3.29-10.94, P < 0.0001) and worse 5 year-OS of colorectal cancer (OR = 2.72, 95% CI = 1.92-3.85, P < 0.00001), esophageal carcinoma (OR = 5.96, 95% CI = 3.48-10.18, P = 0.03), and nonsmall cell lung cancer (OR = 1.69, 95% CI = 1.20-2.38, P = 0.002). Expression of NF-κB is associated with worse survival in most solid tumors irrespective of NF-κB localization.

Overexpression of forkhead box protein M1 (FOXM1) plays a critical role in colorectal cancer

BACKGROUND

The forkhead box M1 (FOXM1), an important regulator of cell differentiation and proliferation, is overexpressed in a number of aggressive human carcinomas. However, the clinical significance of FOXM1 signaling in human colorectal cancer (CRC) pathogenesis remains unknown. The aim of this study was to evaluate the role of FOXM1 in CRC tumorigenesis.

METHODS

We investigated FOXM1 expression in 103 cases of primary CRC and matched normal tissue specimens and explored the underlying mechanisms of altered FOXM1 expression and the impact of this altered expression on CRC proliferation and metastasis using in vitro models of CRC.

RESULTS

The results showed that high expression of FOXM1 staining was 85.44% (88/103) in 103 cases of CRC and 20.39% (21/103) in 103 cases of adjacent non-cancerous tissue samples; the difference of FOXM1 expression between two groups was statistically significant (P < 0.001). Silencing of FOXM1 inhibited the proliferation of CRC cells, and the invasion and migration of CRC cells were distinctly suppressed. Furthermore, FOXM1 knockdown led to substantial reductions in VEGF-A levels in CRC cell lines.

CONCLUSIONS

Our data suggest that the pathogenesis of CRC maybe mediated by FOXM1, and FOXM1 could represent selective targets for the molecularly targeted treatments of CRC.

Prognostic Value of FOXM1 in Patients with Malignant Solid Tumor: A Meta-Analysis and System Review

Forkhead box M1 (FOXM1), a member of the Fox transcription factors family, was closely related with cell cycle. FOXM1 played an important role in MST and prompted a poor prognosis for MST patients. However, there were also some studies revealing no significant association between the FOXM1 expression and prognosis of patients. Therefore, we conducted meta-analysis to investigate whether the expression of FOXM1 was associated with MST prognosis. We collected 36 relevant studies through PubMed database and obtained research data of 4946 patients. Stata 12.0 was used to express the results as hazard ratio (HR) for time-to-event outcomes with 95% confidence intervals (95% CI). It was shown that overexpression of FOXM1 was relevant to worse survival of MST patients (HR = 1.99, 95% CI = 1.79–2.21, P < 0.001; I² = 26.4%, P_h = 0.076). Subgroup analysis suggested that overexpression of FOXM1 in breast cancer (BC), gastric cancer (GC), hepatocellular carcinoma (HCC), pancreatic ductal adenocarcinoma (PDA), and non-small-cell lung cancer (NSCLC) all predicted a worse survival (P < 0.05), in addition to ovarian cancer (OC) (P = 0.084). In conclusion, our research indicated that overexpression of FOXM1 was to the disadvantage of the prognosis for majority of MST and therefore can be used as an evaluation index of prognosis.

Targeting FoxM1 by thiostrepton inhibits growth and induces apoptosis of laryngeal squamous cell carcinoma

PURPOSE

We have previously reported that forkhead box M1 (FoxM1) transcription factor was overexpressed in laryngeal squamous cell carcinoma (LSCC) and was associated with development of LSCC. However, there are limited studies regarding the functional significance of FoxM1 and FoxM1 inhibitor thiostrepton in LSCC. Therefore, the aim of this study was to examine both in vitro and in vivo activity of FoxM1 inhibitor thiostrepton against LSCC cell line and nude mice.

METHODS

Cell viability was studied by CCK-8 assay. Cell growth was evaluated by CFSE staining and cell cycle analysis. Apoptosis was measured by flow cytometry. The mRNA and protein expression were detected by quantitative real-time RT-PCR, Western blot and immunohistochemical staining. Xenograft model of tumor formation was used to investigate how thiostrepton influences tumorigenesis in vivo.

RESULTS

Overexpression of FoxM1 in LSCC cells was down-regulated by thiostrepton in a dose-dependent manner. Thiostrepton caused dose- and time-dependent suppression of cell viability of LSCC. Moreover, thiostrepton induced cell cycle arrest at S phase at early time and inhibited DNA synthesis in LSCC cells in a dose- and time-dependent manner by down-regulation of cyclin D1 and cyclin E1. Thiostrepton also induced dose- and time-dependent apoptosis of LSCC cells by down-regulation of Bcl-2, up-regulation of Bax and p53, and inducing release of cytochrome c accompanied by activation of cleaved caspase-9, cleaved caspase-3 and cleaved PARP. In addition, z-VAD-fmk, a universal inhibitor of caspases, prevented activation of cleavage caspase-3 and abrogates cell death induced by thiostrepton treatment. Furthermore, FADD and cleaved caspase-8 were activated, and expression of cIAP1, XIAP and survivin were inhibited by thiostrepton. Finally, treatment of LSCC cell line xenografts with thiostrepton resulted in tumorigenesis inhibition of tumors in nude mice by reducing proliferation and inducing apoptosis of LSCC cells.

CONCLUSIONS

Collectively, our finding suggest that targeting FoxM1 by thiostrepton inhibit growth and induce apoptosis of LSCC through mitochondrial- and caspase-dependent intrinsic pathway and Fas-dependent extrinsic pathway as well as IAP family. Thiostrepton may represent a novel lead compound for targeted therapy of LSCC.

Targeting forkhead box transcription factors FOXM1 and FOXO in leukemia (Review)

Deregulation of forkhead box (FOX) proteins has been found in many genetic diseases and malignancies including leukemia. Leukemia is a common neoplastic disease of the blood or bone marrow characterized by the presence of immature leukocytes and is one of the leading causes of death due to cancer. Forkhead transcription factors, FOXM1 and FOXO family members (FOXOs), are important mediators in leukemia development. Aberrant expression of FOXM1 and FOXOs results in leukemogenesis. Usually the expression of FOXM1 is upregulated, whereas the expression of FOXOs is downregulated due to phosphorylation, nuclear exclusion and degradation in leukemia. On the one hand, FOXOs are bona fide tumor suppressors, on the other hand, active FOXOs maintain leukemia stem cells and stimulate drug resistance genes, contributing to leukemogenesis. FOXM1 and FOXOs have been proven to be potential targets for the development of leukemia therapeutics. They are also valuable diagnostic and prognostic markers in leukemia for clinical applications. This review summarizes the present knowledge concerning the molecular mechanisms by which FOXM1 and FOXOs modulate leukemogenesis and leukemia development, the clinical relevance of these FOX proteins in leukemia and related areas that warrant further investigation.

The transcription factor FOXM1 (Forkhead box M1): proliferation-specific expression, transcription factor function, target genes, mouse models, and normal biological roles

FOXM1 (Forkhead box M1) is a typical proliferation-associated transcription factor, which stimulates cell proliferation and exhibits a proliferation-specific expression pattern. Accordingly, both the expression and the transcriptional activity of FOXM1 are increased by proliferation signals, but decreased by antiproliferation signals, including the positive and negative regulation by protooncoproteins or tumor suppressors, respectively. FOXM1 stimulates cell cycle progression by promoting the entry into S-phase and M-phase. Moreover, FOXM1 is required for proper execution of mitosis. Accordingly, FOXM1 regulates the expression of genes, whose products control G1/S-transition, S-phase progression, G2/M-transition, and M-phase progression. Additionally, FOXM1 target genes encode proteins with functions in the execution of DNA replication and mitosis. FOXM1 is a transcriptional activator with a forkhead domain as DNA binding domain and with a very strong acidic transactivation domain. However, wild-type FOXM1 is (almost) inactive because the transactivation domain is repressed by three inhibitory domains. Inactive FOXM1 can be converted into a very potent transactivator by activating signals, which release the transactivation domain from its inhibition by the inhibitory domains. FOXM1 is essential for embryonic development and the foxm1 knockout is embryonically lethal. In adults, FOXM1 is important for tissue repair after injury. FOXM1 prevents premature senescence and interferes with contact inhibition. FOXM1 plays a role for maintenance of stem cell pluripotency and for self-renewal capacity of stem cells. The functions of FOXM1 in prevention of polyploidy and aneuploidy and in homologous recombination repair of DNA-double-strand breaks suggest an importance of FOXM1 for the maintenance of genomic stability and chromosomal integrity.

Expression of vascular endothelial growth factor and transcription factors HIF-1, NF-kB expression in squamous cell carcinoma of head and neck; association with proteasome and calpain activities

INTRODUCTION

The transcription factors NF-kB, HIF-1 and vascular endothelial growth factors (VEGF) are known to play an important role in pathogenesis of squamous cell carcinoma of head and neck (SCCHN).

PURPOSE

The aim of the study was to determine the NF-kB, HIF-1 and VEGF, expression their characteristics in squamous cell carcinoma of head and neck.

METHODS

Transcription factors and VEGF expression were measured by ELISA kits. Proteasome and calpain activity were determined using specific fluorogenic substrate. Proteasome subunits composition was measured by Western blot analysis.

RESULTS

In the present study, we revealed the connection between SCCHN lymphogenous metastasis development and NF-kB p50 expression. An increase in total, 26S and 20S proteasome activities and calpain activity was observed in cancer tissues in comparison with agreed standard (non-transformed tissue). The dynamics of changes in proteasome activity and proteasome subunits content during lymph nodes metastasis development had a complex pattern. Nonparametric analysis of variance showed the connection between the extent of metastatic affection of regional lymph nodes, total proteasome activity and LMP2 expression. Proteasome and calpain systems corresponded and interacted with each other. We also revealed a positive correlation between the NF-kB p65 and p50 expression and proteasome activity.

CONCLUSION

Taken together, our results suggest that above mentioned transcription factors and intracellular proteolytic systems are involved in SCCHN progression and metastasis. Moreover, the opportunity of transcription factors regulation by proteasome takes place in oncogenesis of SCCHN. The results provide a basis for new prognostic tests and development of novel targeted therapy.

FOXM1 (Forkhead box M1) in tumorigenesis: overexpression in human cancer, implication in tumorigenesis, oncogenic functions, tumor-suppressive properties, and target of anticancer therapy

FOXM1 (Forkhead box M1) is a typical proliferation-associated transcription factor and is also intimately involved in tumorigenesis. FOXM1 stimulates cell proliferation and cell cycle progression by promoting the entry into S-phase and M-phase. Additionally, FOXM1 is required for proper execution of mitosis. In accordance with its role in stimulation of cell proliferation, FOXM1 exhibits a proliferation-specific expression pattern and its expression is regulated by proliferation and anti-proliferation signals as well as by proto-oncoproteins and tumor suppressors. Since these factors are often mutated, overexpressed, or lost in human cancer, the normal control of the foxm1 expression by them provides the basis for deregulated FOXM1 expression in tumors. Accordingly, FOXM1 is overexpressed in many types of human cancer. FOXM1 is intimately involved in tumorigenesis, because it contributes to oncogenic transformation and participates in tumor initiation, growth, and progression, including positive effects on angiogenesis, migration, invasion, epithelial-mesenchymal transition, metastasis, recruitment of tumor-associated macrophages, tumor-associated lung inflammation, self-renewal capacity of cancer cells, prevention of premature cellular senescence, and chemotherapeutic drug resistance. However, in the context of urethane-induced lung tumorigenesis, FOXM1 has an unexpected tumor suppressor role in endothelial cells because it limits pulmonary inflammation and canonical Wnt signaling in epithelial lung cells, thereby restricting carcinogenesis. Accordingly, FOXM1 plays a role in homologous recombination repair of DNA double-strand breaks and maintenance of genomic stability, that is, prevention of polyploidy and aneuploidy. The implication of FOXM1 in tumorigenesis makes it an attractive target for anticancer therapy, and several antitumor drugs have been reported to decrease FOXM1 expression.

Increased expression of forkhead box M1 protein is associated with poor prognosis in clear cell renal cell carcinoma

Forkhead box protein M1 (FoxM1) is crucial in the regulation of various biological processes, including cell proliferation, organogenesis, and angiogenesis. Overexpression of FoxM1 is associated with carcinogenesis. In this study, immunohistochemistry was carried out to examine FoxM1 expression in clear cell renal cell carcinoma (ccRCC), and these data were examined for correlation with clinicopathological parameters and prognosis. FoxM1 protein had high expression in 37 of 87 cases of ccRCC (42.5 %), which was significantly higher than in normal tissues, and FoxM1 overexpression was significantly associated with tumor stage (P = 0.005) and recurrence (P = 0.027). The Kaplan-Meier survival analysis demonstrated that FoxM1 expression was significantly associated with shorter recurrence-free survival and overall survival (P = 0.007 and P = 0.008, respectively). Multivariate analysis further demonstrated that FoxM1 was an independent prognostic factor for patients with ccRCC. So FoxM1 might be a potential molecular marker to predict the prognosis of patients with ccRCC.

FOXM1 expression correlates with tumor invasion and a poor prognosis of colorectal cancer

FOXM1, a member of the Forkhead Box (Fox) family of transcription factors, plays a critical role in tumor development and metastasis. The aim of this study was to elucidate its role in colorectal cancer (CRC), particularly prognosis and metastasis. Semi-quantitative RT-PCR and Western blot assays were used to measure the expression levels of FOXM1 mRNA and protein in 15 CRC and adjacent normal mucosa tissues. Immunohistochemical assay was performed to detect FOXM1 protein expression in 112 CRC tissues and further determine its clinicopathological and prognostic significance. RNA interference (RNAi) was used to knockdown endogenous FOXM1 expression in CRC cell lines and to analyze the effects of FOXM1 knockdown on migration and invasion of CRC cells. The relative expression levels of FOXM1 mRNA and protein were significantly higher in CRC tissues than in adjacent normal mucosa tissues (P<0.01). In addition, the immunostaining of FOXM1 protein was stronger in CRC tissues than in adjacent normal mucosa tissues. By statistical analysis, we showed that high FOXM1 expression was closely correlated with the presence of lymph node metastasis, incidence of liver metastasis, and advanced TNM stage. Moreover, the cumulative 5-year survival rate of CRC patients with high FOXM1 expression was lower than that of those with low FOXM1 expression (P=0.0047). Multivariate analysis showed that the status of FOXM1 expression was an independent prognostic factor for CRC patients (P=0.025). Furthermore, RNAi-mediated FOXM1 knockdown could significantly inhibit growth, migration and invasion of CRC cells. Our results showed that FOXM1 over-expression is a molecular marker predicting increased invasive/metastatic potential of CRC and a poorer prognosis.

Fascin-1, ezrin and paxillin contribute to the malignant progression and are predictors of clinical prognosis in laryngeal squamous cell carcinoma

Aims

Fascin-1, ezrin and paxillin, cytoskeleton-associated proteins, have been implicated in several human cancers, but their role in laryngeal squamous cell carcinoma (LSCC) is unknown. We investigated the association of their expression and clinicopathologic factors and their prognostic value in LSCC.

Materials and Methods

Quantitative RT-PCR and western blot analyses were used to examine mRNA and protein levels in 10 fresh LSCC specimens and 10 corresponding adjacent normal margin (ANM) tissues from patients undergoing surgery in 2012. We used immunohistochemistry to retrospectively study 216 paraffin blocks of LSCC samples from patients (193 men) who had undergone surgery between 2000 and 2006 and had not received special treatment before the diagnosis. Univariate analysis of patient survival involved the Kaplan–Meier method. Multivariate analyses involved the Cox proportional hazards model.

Results

The relative mRNA and protein levels of fascin-1, ezrin and paxillin were significantly greater in LSCC than ANM tissue (P<0.05). The high expression of fascin-1, ezrin or paxillin was positively correlated with poor tumor differentiation, cervical lymph node metastasis (N+), and advanced clinical stage (III+IV) (P<0.05) but not sex or metastasis. In addition, a high expression of fascin-1 (P = 0.007) or ezrin (P = 0.047) was associated with advanced tumor stage (T3+T4). The expression of fascin-1 was higher in smokers than non-smokers (P = 0.019). A high expression of fascin-1, ezrin or paxillin was associated with poor prognosis.

Conclusions

Fascin-1, ezrin and paxillin may be prognostic of poor outcome with LSCC after surgery. Our study may lead to establishing new molecular therapeutic targets and/or prognostic biomarkers in LSCC.

Targeting FOXM1 in cancer

Oncogenic transcription factor FOXM1 is overexpressed in the majority of human cancers. In addition, FOXM1 has been implicated in cell migration, invasion, angiogenesis and metastasis. The important role of FOXM1 in cancer affirms its significance for therapeutic intervention. Current data suggest that targeting FOXM1 in mono- or combination therapy may have promising therapeutic benefits for the treatment of cancer. However, challenges with the delivery of anti-FOXM1 siRNA to tumors and the absence of small molecules, which specifically inhibit FOXM1, are delaying the development of FOXM1 inhibitors as feasible anticancer drugs. In this review, we describe and summarize the efforts that have been made to target FOXM1 in cancer and the consequences of FOXM1 suppression in human cancer cells.

Overexpression of FoxM1 is associated with tumor progression in patients with clear cell renal cell carcinoma

Background

Fork head box M1 (FoxM1) is a proliferation-associated transcription factor essential for cell cycle progression. Numerous studies have documented that FoxM1 has multiple functions in tumorigenesis and its elevated levels are frequently associated with cancer progression. The present study was conducted to investigate the expression of FoxM1 and its prognostic significance in clear cell renal cell carcinoma (ccRCC). Meanwhile, the function of FoxM1 in human ccRCC was further investigated in cell culture models.

Methods

Real-time quantitative PCR, western blot and immunohistochemistry were used to explore FoxM1 expression in ccRCC cell lines and primary ccRCC clinical specimens. FoxM1 expression was knocked down by small interfering RNA (siRNA) in Caki-1 and 786-O cells; proliferation, colony formation, cell cycle, migration, invasion, and angiogenesis were assayed.

Results

FoxM1 expression was up-regulated in the majority of the ccRCC clinical tissue specimens at both mRNA and protein levels. Clinic pathological analysis showed that FoxM1 expression was significantly correlated with primary tumor stage (P <0.001), lymph node metastasis (P = 0.01), distant metastasis (P = 0.01), TNM stage (P < 0.001) and histological grade (P = 0.003). The Kaplan–Meier survival curves revealed that high FoxM1 expression was associated with poor prognosis in ccRCC patients (P < 0.001). FoxM1 expression was an independent prognostic marker of overall ccRCC patient survival in a multivariate analysis (P = 0.008). Experimentally, we found that down-regulation of FoxM1 inhibited cell proliferation and induced cell cycle arrest with reduced expression of cyclin B1, cyclin D1, and Cdk2, and increased expression of p21 and p27. Also, down-regulation of FoxM1 reduced expression and activity of matrix metalloproteinase-2 (MMP-2), MMP-9 and vascular endothelial growth factor (VEGF), resulting in the inhibition of migration, invasion, and angiogenesis.

Conclusions

These results suggest that FoxM1 expression is likely to play important roles in ccRCC development and progression, and that FoxM1 is a prognostic biomarker and a promising therapeutic target for ccRCC.