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

Injury-induced Foxm1 expression in the mouse kidney drives epithelial proliferation by a cyclin F-dependent mechanism

Acute kidney injury (AKI) strongly upregulates the transcription factor Foxm1 in the proximal tubule in vivo, and Foxm1 drives epithelial proliferation in vitro. Here, we report that deletion of Foxm1 either with a nephron-specific Cre driver or by inducible global deletion reduced proximal tubule proliferation after ischemic injury in vivo. Foxm1 deletion led to increased AKI to chronic kidney disease transition, with enhanced fibrosis and ongoing tubule injury 6 weeks after injury. We report ERK mediated FOXM1 induction downstream of the EGFR in primary proximal tubule cells. We defined FOXM1 genomic binding sites by cleavage under targets and release using nuclease (CUT&RUN) and compared the genes located near FOXM1 binding sites with genes downregulated in primary proximal tubule cells after FOXM1 knockdown. The aligned data sets revealed the cell cycle regulator cyclin F (CCNF) as a putative FOXM1 target. We identified 2 cis regulatory elements that bound FOXM1 and regulated CCNF expression, demonstrating that Ccnf is strongly induced after kidney injury and that Foxm1 deletion abrogates Ccnf expression in vivo and in vitro. Knockdown of CCNF also reduced proximal tubule proliferation in vitro. These studies identify an ERK/FOXM1/CCNF signaling pathway that regulates injury-induced proximal tubule cell proliferation.

REEP4 as Potential Biomarker Associated with Predictive Prognosis and Immune Response in Kidney Clear Cell Carcinoma

Kidney clear cell carcinoma (KIRC) commonly presents with metastases upon diagnosis, highlighting the critical need to identify more precise biomarkers for early detection, intervention, and personalized treatment. Although The REEP family has been investigated in cancer development, the specific relationship between REEP4 and cancer remains unclear. In our study, we employed bioinformatics analysis and conducted fundamental experiments to evaluate the potential of REEP4 as a biomarker for predicting the prognosis and therapeutic efficacy of KIRC. Comparing KIRC tumor tissues to normal tissues, we observed a significant upregulation in REEP4 expression, with higher levels of REEP4 correlating positively with tumor malignancy. Further COX regression analysis, as well as single and multifactorial analyses, confirmed that high REEP4 expression indicated lower survival rates in KIRC. Gene function analysis also identified associations between REEP4 and critical pathways such as the cell cycle, along with its involvement in protein binding. Furthermore, our investigation of the immune response suggests that a favorable immunotherapeutic response is linked to a reduction in REEP4 expression. Subsequently, we conducted in vitro experiments to confirm the overexpression of REEP4 in KIRC tumor tissues and renal cancer cells. In summary, our study revealed a close association between REEP4 expression and KIRC, emphasizing its correlation with prognosis and the immune response. These findings suggest that REEP4 is a potential biomarker for KIRC.

Overexpression of cyclin F/CCNF as an independent prognostic factor for poor survival in clear cell renal cell carcinoma

Cyclin F (encoded by CCNF gene) has been reported to be implicated in the pathobiology of several human cancers. However, its potential clinical significance in clear cell renal cell carcinoma (ccRCC) remains unknown. The present study aimed to evaluate the potential significance of cyclin F, assessed by immunohistochemical (IHC) staining and molecular (bioinformatics) techniques, as a prognostic marker in ccRCC in relation to clinicopathological features and outcomes. IHC staining was performed using two independent ccRCC tissue array cohorts, herein called tissue macroarray (TMA)_1 and tissue microarray (TMA)_2, composed of 108 ccRCCs and 37 histologically normal tissues adjacent to the tumor (NAT) and 192 ccRCCs and 16 normal kidney samples, respectively. The mRNA expression data were obtained from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) public datasets, followed by bioinformatics analysis of biological mechanisms underlying prognosis. The relationship between immune cell infiltration level and CCNF expression in ccRCC was investigated using the Tumor Immune Estimation Resource 2.0 (TIMER2) and Gene Expression Profiling Interactive Analysis 2 (GEPIA2). Cyclin F expression was significantly elevated in ccRCC lesions compared to both NAT and normal renal tissues. Likewise, CCNF mRNA was markedly increased in ccRCCs relative to non-cancerous tissues. In all analyzed cohorts, tumors with features of more aggressive behavior were more likely to display cyclin F/CCNF-high expression than low. Furthermore, patients with high cyclin F/CCNF expression had shorter overall survival (OS) times than those with low expression. In addition, multivariable analysis revealed that cyclin F/CCNF-high expression was an independent prognostic factor for poor OS in ccRCC. Enrichment analysis for mechanistically relevant processes showed that CCNF and its highly correlated genes initiate the signaling pathways that eventually result in uncontrolled cell proliferation. CCNF expression was also correlated with immune cell infiltration and caused poor outcomes depending on the abundance of tumor-infiltrating immune cells in ccRCC. Our findings suggest that cyclin F/CCNF expression is likely to have an essential role in ccRCC pathobiology through regulating multiple oncogenic signaling pathways and affecting the tumor immune microenvironment and may serve as prognostic biomarker and promising therapeutic target in ccRCC.

PLK1 and FoxM1 expressions positively correlate in papillary thyroid carcinoma and their combined inhibition results in synergistic anti-tumor effects

Polo-like kinase 1 (PLK1; also known as serine/threonine-protein kinase PLK1) serves as a central player in cell proliferation, exerting critical regulatory roles in mitotic processes and cell survival. We conducted an analysis of PLK1 protein expression in a large cohort of samples from papillary thyroid carcinoma (PTC) patients and examined its functional significance in PTC cell lines, both in vitro and in vivo. PLK1 overexpression was noted in 54.2% of all PTC and was significantly associated with aggressive clinicopathological parameters; it was also found to be an independent prognostic marker for shorter recurrence-free survival. Given the significant association between PLK1 and forkhead box protein M1 (FoxM1), and their concomitant overexpression in a large proportion of PTC samples, we explored their correlation and their combined inhibitions in PTC in vitro and in vivo. Inhibition of PLK1 expression indeed suppressed cell proliferation, leading to cell cycle arrest and apoptosis in PTC cell lines. Significantly, the downregulation of PLK1 reduced the self-renewal capability of spheroids formed from PTC cells. Immunoprecipitation analysis shows that PLK1 binds to FoxM1 and vice versa in vitro. Mechanistically, PLK1 knockdown suppresses FoxM1 expression, whereas inhibition of FoxM1 does not affect PLK1 expression, which suggests that PLK1 acts through the FoxM1 pathway. The combined treatment of a PLK1 inhibitor (volasertib) and a FoxM1 inhibitor (thiostrepton) demonstrated a synergistic effect in reducing PTC cell growth in vitro and delaying tumor growth in vivo. This study highlights the important role of PLK1 in PTC tumorigenesis and prognosis. It also highlights the synergistic therapeutic potential of dual-targeting PLK1 and FoxM1 in PTC, unveiling a potential innovative therapeutic strategy for managing aggressive forms of PTC.

Abnormal expression of FOXM1 in carcinogenesis of renal cell carcinoma: From experimental findings to clinical applications

Renal cell carcinoma (RCC) is a prevalent malignancy within the genitourinary system. At present, patients with high-grade or advanced RCC continue to have a bleak prognosis. Mounting research have emphasized the significant involvement of Forkhead box M1 (FOXM1) in RCC development and progression. Therefore, it is imperative to consolidate the existing evidence regarding the contributions of FOXM1 to RCC tumorigenesis through a comprehensive review. This study elucidated the essential functions of FOXM1 in promoting RCC growth, invasion, and metastasis by regulating cell cycle progression, DNA repair, angiogenesis, and epithelial-mesenchymal transition (EMT). Also, FOXM1 might serve as a novel diagnostic and prognostic biomarker as well as a therapeutic target for RCC. Clinical findings demonstrated that the expression of FOXM1 was markedly upregulated in RCC samples, while a high level of FOXM1 was found to be associated with a poor overall survival rate of RCC. Furthermore, it is worth noting that FOXM1 may have a significant impact on the resistance of renal cell carcinoma (RCC) to radiotherapy. This observation suggests that inhibiting FOXM1 could be a promising strategy to impede the progression of RCC and enhance its sensitivity to radiotherapy. The present review highlighted the pivotal role of FOXM1 in RCC development. FOXM1 has the capacity to emerge as not only a valuable diagnostic and prognostic tool but also a viable therapeutic option for unresectable RCC.

Mitotic kinase inhibitors as Therapeutic Interventions for Prostate Cancer: Evidence from In vitro Studies

Prostate cancer is one of the devastating diseases characterized by genetic changes leading to uncontrolled growth and metastasis of the cells of the prostate gland and affects men worldwide. Conventional hormonal and chemotherapeutic agents are effective in mitigating the disease if diagnosed at an early stage. All dividing eukaryotic cells require mitotic progression for the maintenance of genomic integrity in progeny populations. The protein kinases, upon activation and de-activation in an ordered fashion, lead to spatial and temporal regulation of the cell division process. The entry into mitosis along with the progression into sub-phases of mitosis is ensured due to the activity of mitotic kinases. These kinases include Polo-Like-Kinase 1 (PLK1), Aurora kinases, and Cyclin-Dependent-Kinase 1 (CDK1), among others. The mitotic kinases, among others, are usually overexpressed in many cancers and can be targeted using small molecule inhibitors to reduce the effects of these regulators on mechanisms, such as regulation of genomic integrity and mitotic fidelity. In this review, we attempted to discuss the appropriate functions of mitotic kinases revealed through cell culture studies and the impact of their respective inhibitors derived in pre-clinical studies. The review is designed to elucidate the growing field of small molecule inhibitors and their functional screening or mode of action at the cellular and molecular level in the context of Prostate Cancer. Therefore, studies performed specifically on cells of Prostatic-origin are narrated in this review, culminating in a comprehensive view of the specific field of mitotic kinases that can be targeted for therapy of Prostate cancer.

Impairment of FOXM1 expression in mesenchymal cells from patients with myeloid neoplasms, de novo and therapy-related, may compromise their ability to support hematopoiesis

Bone marrow mesenchymal stem cells (BM-MSCs) exhibit multiple abnormalities in myelodysplastic syndromes (MDS) and acute myeloid leukemias (AML), including reduced proliferative and clonogenic capacity, altered morphology, impaired immunoregulatory properties and capacity to support hematopoiesis. Here, we investigated expression of the FOXM1 gene, a transcription factor driving G2/M gene expression, in BM-MSCs isolated from patients with MDS and AML, de novo and therapy-related, compared to BM-MSCs isolated from healthy donors (HD). We observed a statistically significant downregulation of FOXM1 expression in BM-MSCs isolated from MDS and AML patients, as compared to controls. In parallel, expression of FOXM1 mitotic targets (CCNB1, CDC20, PLK1 and NDC80) was suppressed in patients' BM-MSCs, as compared to HD. No differences in the expression of FOXM1 and its mitotic targets were observed in BM-mononuclear cells from the different sources. From a functional standpoint, silencing of FOXM1 mRNA in healthy MSC induced a significant decrease in the expression of its targets. In this line, healthy MSC silenced for FOXM1 showed an impaired ability to support hematopoiesis in vitro. These findings suggest that deregulation of FOXM1 may be involved in the senescent phenotype observed in MSC derived from myeloid neoplasms.

Transcriptomic and Functional Evidence for Differential Effects of MCF-7 Breast Cancer Cell-Secretome on Vascular and Lymphatic Endothelial Cell Growth

Vascular and lymphatic vessels drive breast cancer (BC) growth and metastasis. We assessed the cell growth (proliferation, migration, and capillary formation), gene-, and protein-expression profiles of Vascular Endothelial Cells (VECs) and Lymphatic Endothelial Cells (LECs) exposed to a conditioned medium (CM) from estrogen receptor-positive BC cells (MCF-7) in the presence or absence of Estradiol. We demonstrated that MCF-7-CM stimulated growth and capillary formation in VECs but inhibited LEC growth. Consistently, MCF-7-CM induced ERK1/2 and Akt phosphorylation in VECs and inhibited them in LECs. Gene expression analysis revealed that the LECs were overall (≈10-fold) more sensitive to MCF-7-CM exposure than VECs. Growth/angiogenesis and cell cycle pathways were upregulated in VECs but downregulated in LECs. An angiogenesis proteome array confirmed the upregulation of 23 pro-angiogenesis proteins in VECs. In LECs, the expression of genes related to ATP synthesis and the ATP content were reduced by MCF-7-CM, whereas MTHFD2 gene, involved in folate metabolism and immune evasion, was upregulated. The contrasting effect of MCF-7-CM on the growth of VECs and LECs was reversed by inhibiting the TGF-β signaling pathway. The effect of MCF-7-CM on VEC growth was also reversed by inhibiting the VEGF signaling pathway. In conclusion, BC secretome may facilitate cancer cell survival and tumor growth by simultaneously promoting vascular angiogenesis and inhibiting lymphatic growth. The differential effects of BC secretome on LECs and VECs may be of pathophysiological relevance in BC.

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

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

Dysregulation of miR-23b-5p promotes cell proliferation via targeting FOXM1 in hepatocellular carcinoma

Growing evidence demonstrates that MicroRNAs (miRNAs) play an essential role in contributing to tumor development and progression. However, the underlying role and mechanisms of miR-23b-5p in hepatocellular carcinoma (HCC) formation remain unclear. Our study showed that miR-23b-5p was downregulated in the HCC tissues and cell lines, and lower expression of miR-23b-5p was associated with more severe tumor size and poorer survival. Gain- or loss-of-function assays demonstrated that miR-23b-5p induced G0/G1 cell cycle arrest and inhibited cell proliferation both in vitro and in vivo. qRT-PCR, western blot and luciferase assays verified that Mammalian transcription factor Forkhead Box M1 (FOXM1), upregulated in HCC specimens, was negatively correlated with miR-23b-5p expression and acted as a direct downstream target of miR-23b-5p. In addition, miR-23b-5p could regulate cyclin D1 and c-MYC expression by directly targeting FOXM1. Further study revealed that restoration of FOXM1 neutralized the cell cycle arrest and cell proliferation inhibition caused by miR-23b-5p. Taken together, our findings suggest that miR-23b-5p acted as a tumor suppressor role in HCC progression by targeting FOXM1 and may serve as a potential novel biomarker for HCC diagnosis and prognosis.

FOXM1 and Cancer: Faulty Cellular Signaling Derails Homeostasis

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

Exogenous delivery of microRNA-134 (miR-134) using α-tocopherol-based PEGylated liposome for effective treatment in skin squamous cell carcinoma

MicroRNAs (miRNAs) are involved in the pathogenesis of several cancers including skin squamous cell carcinoma (sSCC), and miR-134 is reported to possess tumor inhibition properties. The present study is an attempt to study the mechanistic role and antitumor property of miR-134 in sSCC. For this purpose, α-tocopherol PEG 1000 succinate (TPGS)-based PEGylated liposome was formulated and encapsulated with miR-134 (TP-miR-LP). CCK-8 assay results showed that miR-134 exhibited a concentration-dependent decrease in the cell viability of A-431 cells. Importantly, TPGS-based TP-miR-LP showed significantly (p < 0.05) lower cell viability compared with that of miR-134-loaded PEGylated liposome (miR-LP). Western blot analysis clearly indicates the specific targeting ability of miR-134 (TP-miR-LP) towards the Forkhead Box M1 (FOXM1) in the cancer cells. The apoptosis rate of the cells was significantly increased in TP-miR-LP (~ 38%) than that of miR-LP (~ 15%), respectively with significant inhibition of cell migration. Importantly, tumors treated with TP-miR-LP grew significantly slower compared with that of any other formulation group in the xenograft animal model. Present results clearly demonstrate the tumor suppressive effect of miR-134 through the downregulation of FOXM1 which subsequently blocks the downstream signaling pathways. These findings suggest the translational potential of miR-134 towards designing formulation strategies for sSCC treatment. Graphical abstract.

OTUB1-mediated deubiquitination of FOXM1 up-regulates ECT-2 to promote tumor progression in renal cell carcinoma

Background

OTUB1 (ovarian tumor domain protease domain-containing ubiquitin aldehyde-binding proteins)-mediated deubiquitination of FOXM1 (Forkhead box M1) participates in carcinogenesis of various tumors. We aim to investigate the effect and mechanism of OTUB1/FOXM1 on RCC (renal cell carcinoma) progression. Expression levels of OTUB1 in RCC tissues and cell lines were examined by qRT-PCR (quantitative real-time polymerase chain reaction) and immunohistochemistry. Cell proliferation was measured with CCK8 (Cell Counting Kit-8) and colony formation assays. Wound healing and transwell assays were used to determine cell migration and invasion, respectively. The effect of OTUB1 on FOXM1 ubiquitination was examined by Immunoprecipitation. Western blot was used to uncover the underlying mechanism. In vivo subcutaneous xenotransplanted tumor model combined with immunohistochemistry and western blot were used to examine the tumorigenic function of OTUB1.

Results

OTUB1 was up-regulated in RCC tissues and cell lines, and was associated with poor prognosis of RCC patients. Knockdown of OTUB1 inhibited cell viability and proliferation, as well as migration and invasion of RCC cells. Mechanistically, knockdown of OTUB1 down-regulated FOXM1 expression by promoting its ubiquitination. Down-regulation of FOXM1 inhibited ECT2 (epithelial cell transforming 2)-mediated Rho signaling. Moreover, the inhibition of RCC progression caused by OTUB1 knockdown was reversed by FOXM1 over-expression. In vivo subcutaneous xenotransplanted tumor model also revealed that knockdown of OTUB1 could suppress in vivo RCC growth via down-regulation of FOXM1-mediated ECT2 expression.

Conclusions

OTUB1-mediated deubiquitination of FOXM1 up-regulates ECT-2 to promote tumor progression in RCC, providing a new potential therapeutic target for RCC treatment.

Sensitization to oxidative stress and G2/M cell cycle arrest by histone deacetylase inhibition in hepatocellular carcinoma cells

Oxidative stress resistance in cancer cells has contributed to multi-drug resistance, which poses a serious challenge to cancer therapy. To surmount this, combinatorial treatment involving anticancer drugs and histone deacetylase inhibitors (HDACi) have emerged as a chemotherapeutic option. Yet, HDACi's role in redox states of cancer cells still requires elucidation. In the present study, we hypothesized that HDACi sensitizes cancer cells to oxidative stress and results in G2/M cell cycle arrest. Cell viability and cell cycle were analyzed using Cell Counting Kit 8 (CCK8) and fluorescent activated cell sorting (FACS), respectively. The transcriptomes of cells were investigated by massive analysis of cDNA end (MACE). Expression of mRNA and proteins were analyzed by quantitative real-time PCR (qPCR) and Western blot, respectively. Intracellular oxidative stress induced by tert-Butyl hydroperoxide (tBHP) reduced cell viability and resulted in G2/M cell cycle arrest in a dose-dependent manner in hepatocellular carcinoma (HCC) cells. The effects of sorafenib on cell cycle arrest and HCC viability were enhanced through HDACi treatment. MACE revealed that genes related to progression of G2/M cell cycle including Foxm1, Aurka, Plk1, and Ccnb1 were significantly down-regulated in tBHP and HDACi-treated HepG2 cells. Inhibition of FOXM1 with thiostrepton also resulted in reduced cell viability and expression of FOXM1 target genes such as Aurka, Plk1, and Ccnb1. These results indicate that HDACi sensitizes HepG2 cells to oxidative stress and results in G2/M cell cycle arrest via down-regulation of FOXM1, which plays a key role in progression of G2/M cell cycle.

FOXM1 drives proximal tubule proliferation during repair from acute ischemic kidney injury

The proximal tubule has a remarkable capacity for repair after acute injury, but the cellular lineage and molecular mechanisms underlying this repair response are incompletely understood. Here, we developed a Kim1-GFPCreERt2 knockin mouse line (Kim1-GCE) in order to perform genetic lineage tracing of dedifferentiated cells while measuring the cellular transcriptome of proximal tubule during repair. Acutely injured genetically labeled clones coexpressed KIM1, VIMENTIN, SOX9, and KI67, indicating a dedifferentiated and proliferative state. Clonal analysis revealed clonal expansion of Kim1+ cells, indicating that acutely injured, dedifferentiated proximal tubule cells, rather than fixed tubular progenitor cells, account for repair. Translational profiling during injury and repair revealed signatures of both successful and unsuccessful maladaptive repair. The transcription factor Foxm1 was induced early in injury, was required for epithelial proliferation in vitro, and was dependent on epidermal growth factor receptor (EGFR) stimulation. In conclusion, dedifferentiated proximal tubule cells effect proximal tubule repair, and we reveal an EGFR/FOXM1-dependent signaling pathway that drives proliferative repair after injury.

Polo-like kinase 1 (Plk1) inhibition synergizes with taxanes in triple negative breast cancer

Within triple negative breast cancer, several molecular subtypes have been identified, underlying the heterogeneity of such an aggressive disease. The basal-like subtype is characterized by mutations in the TP53 gene, and is associated with a low pathologic complete response rate following neoadjuvant chemotherapy. In a genome-scale short hairpin RNA (shRNA) screen of breast cancer cells, polo-like kinase 1 (Plk1) was a frequent and strong hit in the basal breast cancer cell lines indicating its importance for growth and survival of these breast cancer cells. Plk1 regulates progression of cells through the G2-M phase of the cell cycle. We assessed the activity of two ATP-competitive Plk1 inhibitors, GSK461364 and onvansertib, alone and with a taxane in a set of triple negative breast cancer cell lines and in vivo. GSK461364 showed synergism with docetaxel in SUM149 (Combination Index 0.70) and SUM159 (CI, 0.62). GSK461364 in combination with docetaxel decreased the clonogenic potential (interaction test for SUM149 and SUM159, p<0.001 and p = 0.01, respectively) and the tumorsphere formation of SUM149 and SUM159 (interaction test, p = 0.01 and p< 0.001). In the SUM159 xenograft model, onvansertib plus paclitaxel significantly decreased tumor volume compared to single agent paclitaxel (p<0.0001). Inhibition of Plk1 in combination with taxanes shows promising results in a subset of triple negative breast cancer intrinsically resistant to chemotherapy. Onvansertib showed significant tumor volume shrinkage when combined with paclitaxel in vivo and should be considered in clinical trials for the treatment of triple negative cancers.

Multi-omics analysis reveals epithelial-mesenchymal transition-related gene FOXM1 as a novel prognostic biomarker in clear cell renal carcinoma

Identification of novel clinical biomarker in clear cell renal carcinoma (ccRCC) is warranted. Integrating transcriptome (n=1669), DNA methylation (n=577) and copy number data (n=832), we developed a method to identify driver biomarkers by analyzing the omics-level dynamics of Epithelial-Mesenchymal Transition (EMT)-related genes in ccRCC. We first identified 504 expression dynamic changed genes involved in ccRCC-associated key pathways such as EMT, cell cycle, EGFR and PI3K/AKT signaling. Further analysis identified 229 (90 gene promoters) aberrant expression quantitative trait methylation (eQTM) and 256 genes with expression quantitative trait copy number (eQTCN) alterations. Among them, FOXM1 was affected by both eQTM and eQTCN. FOXM1 copy number amplification (115/500, 23% of patients), occurred in an amplified peak in chromosome 12q13.3, was enriched in late-stage ccRCC samples and was associated with worse survival. FOXM1-overexpressed pT3 patients with distant metastasis showed ~25% shorter overall survival in both training (log-rank P=0.006) and validation (log-rank P=0.018) cohorts. The eQTM-gene hybrid signature (cg00044170 and FOXM1), superior to either gene expression or DNA methylation alone, showed great potential in diagnosing localized ccRCC in training (area under curve = 0.958) and validation datasets. FOXM1 could be a novel prognostic biomarker and shed light for early diagnosis at molecular level in ccRCC.

High impact of miRNA-4521 on FOXM1 expression in medulloblastoma

Medulloblastoma, an embryonal tumor of the cerebellum/fourth ventricle, is one of the most frequent malignant brain tumors in children. Although genetic variants are increasingly used in treatment stratification, survival of high-risk patients, characterized by leptomeningeal dissemination, TP53 mutation or MYC amplification, is still poor. FOXM1, a proliferation-specific oncogenic transcription factor, is deregulated in various solid tumors, including medulloblastoma, and triggers cellular proliferation, migration and genomic instability. In tissue samples obtained from medulloblastoma patients, the significant upregulation of FOXM1 was associated with a loss of its putative regulating microRNA, miR-4521. To understand the underlying mechanism, we investigated the effect of miR-4521 on the expression of the transcription factor FOXM1 in medulloblastoma cell lines. Transfection of this microRNA reduced proliferation and invasion of several medulloblastoma cell lines and induced programmed cell death through activation of caspase 3/7. Further, downstream targets of FOXM1 such as PLK1 and cyclin B1 were significantly reduced thus affecting the cell cycle progression in medulloblastoma cell lines. In conclusion, a restoration of miRNA-4521 may selectively suppress the pathophysiological effect of aberrant FOXM1 expression and serve as a targeted approach for medulloblastoma therapy.

Long noncoding RNA ENST00000413528 sponges microRNA-593-5p to modulate human glioma growth via polo-like kinase 1

AIMS

In this study, we examined the expression of lncRNA ENST00000413528 in glioma and determined its role in glioma development.

METHODS

LncRNA ENST00000413528 was detected in glioma tissues by lncRNA microarray. Then, we performed real-time PCR, CCK-8, colony formation assay, flow cytometry, caspase-3/7 assay and animal experiment to detect the function of ENST00000413528 in glioma after ENST00000413528 knockdown. Subsequent bioinformatics analysis, luciferase reporter assays and RNA immunoprecipitation (RIP) assay western blotting indicated possible downstream regulatory molecules. The expression of PLK1 in glioma tissues was also examined by immunohistochemistry staining.

RESULTS

Expression of ENST00000413528 was significantly increased in glioma tissues and LN229 and U251 cells. PLK1 protein could not be detected in peritumoral brain edema (PTBE) tissues; however, it showed an increasing number of positively cytoplasmic stained from WHO-Grade II to Grade III gliomas. Knockdown of ENST00000413528 in glioma cells inhibited cell proliferation and colony formation abilities, induced the G0/G1 arrest of the cell cycle, and promoted apoptosis. The dual reporter assay and RNA immunoprecipitation assay verified the interaction between ENST00000413528 and miR-593. We also demonstrated that polo-like kinase 1 (PLK1) was regulated by miR-593; PLK1 messenger RNA lacking 3'UTR partially reversed the effects caused by ENST00000413528 knockdown or miR-593 upregulation.

CONCLUSION

lncRNA ENST00000413528 is closely related to the development of glioma via the miR-593-5p/PLK1 pathway.

Subgroup-specific prognostic signaling and metabolic pathways in pediatric medulloblastoma

Background

Using a pathway-focused approach, we aimed to provide a subgroup-specific basis for finding novel therapeutic strategies and further refinement of the risk stratification in pediatric medulloblastoma.

Method

Based on genome-wide Cox regression and Gene Set Enrichment Analysis, we investigated prognosis-related signaling pathways and core genes in pediatric medulloblastoma subgroups using 530 patient data from Medulloblastoma Advanced Genomic International Consortium (MAGIC) project. We further examined the relationship between expression of the prognostic core genes and frequent chromosome aberrations using broad range copy number change data.

Results

In SHH subgroup, relatively high expression of the core genes involved in p53, PLK1, FOXM1, and Aurora B signaling pathways are associated with poor prognosis, and their average expression synergistically increases with co-occurrence of losses of 17p, 14q, or 10q, or gain of 17q. In Group 3, in addition to high MYC expression, relatively elevated expression of PDGFRA, IGF1R, and FGF2 and their downstream genes in PI3K/AKT and MAPK/ERK pathways are related to poor survival outcome, and their average expression is increased with the presence of isochromosome 17q [i(17q)] and synergistically down-regulated with simultaneous losses of 16p, 8q, or 4q. In Group 4, up-regulation of the genes encoding various immune receptors and those involved in NOTCH, NF-κB, PI3K/AKT, or RHOA signaling pathways are associated with worse prognosis. Additionally, the expressions of Notch genes correlate with those of the prognostic immune receptors. Besides the Group 4 patients with previously known prognostic aberration, loss of chromosome 11, those with loss of 8q but without i(17q) show excellent survival outcomes and low average expression of the prognostic core genes whereas those harboring 10q loss, 1q gain, or 12q gain accompanied by i(17q) show bad outcomes. Finally, several metabolic pathways known to be reprogrammed in cancer cells are detected as prognostic pathways including glutamate metabolism in SHH subgroup, pentose phosphate pathway and TCA cycle in Group 3, and folate-mediated one carbon-metabolism in Group 4.

Conclusions

The results underscore several subgroup-specific pathways for potential therapeutic interventions: SHH-GLI-FOXM1 pathway in SHH subgroup, receptor tyrosine kinases and their downstream pathways in Group 3, and immune and inflammatory pathways in Group 4.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5742-x) contains supplementary material, which is available to authorized users.

MiRNA-134 suppresses esophageal squamous cell carcinoma progression by targeting FOXM1

Previous studies showed that the dysregulation of miRNAs was closely associated with cancer progression. The aim of this study was to verify whether miR-134, miR-10a, miR-29c, miR-942, miR-93, and miR-218 could inhibit esophageal squamous cell carcinoma (ESCC) cell invasion and migration. ESCC tissue and normal esophageal tissue adjacent to carcinoma from patients (54 cases) undergoing surgery were collected. RT-PCR was used to test the expression of miR-134, miR-10a, miR-29c, miR-942, miR-93, and miR-218 in these tissues. In addition, western blot was applied to test the expression of MMP-2, MMP-9, COL1A1, COL1A5 and FOXM1. In the vitro experiment, EC9706 cells were transfected with miR-134 mimics, then wound healing was employed to test the migratory ability of EC9706 cells. Transwell chambers was used to test the invasion ability of cells. The expression of MMP-2, MMP-9, COL1A1, COL1A5, and FOXM1 waas detected by western blot. In order to confirm whether FOXM1-3'-UTR was the target gene of miR-134, we performed a luciferase assay. FOXM1 over-expression plasmid was transfected to further confirm miR-134 played its role by targeting FOXM1. Our results showed that the expression of miR-134 was decreased in the ESCC tissue compared with normal esophageal tissue, (P<0.01), but the expression of MMP-2, MMP-9, COL1A1, COL1A5 and FOXM1 were significantly increased (P<0.01). In an in vitro experiment, compared with the mimic control, the expression of MMP-2, MMP-9, COL1A1, COL1A5 and FOXM1 were decreased in the miR-134 mimic-transfected EC9706 cells (P<0.01). The migration and invasion activity of EC9706 cells was also decreased after transfection with miR-134 mimics (P<0.01). The luciferase activity of the FOXM1-3'-UTR plasmid was significantly suppressed by miR-134 (P<0.01). Overexpression of FOXM1 abrogated miR-134-mediated inhibition of EC9706 cell migration and invasion. In conclusion, miR-134 inhibited EC9706 cell migration and invasion by targeting FOXM1. miR-134 may be a novel treatment target for ESCC.

MicroRNA‑320a suppresses tumour cell proliferation and invasion of renal cancer cells by targeting FoxM1

An increasing body of evidence has indicated that microRNAs (miRNAs/miRs) may play an important role in tumourigenesis and tumour progression. Recent studies have demonstrated that miR‑320a is aberrantly expressed in a variety of different types of human cancer. The results of the present study confirmed that the expression of miR‑320a was decreased in clinical specimens and cell lines. Expression of miR‑320a inhibited the growth and invasive ability of ACHN and Caki‑1 cells. Bioinformatics analysis and a luciferase reporter assay demonstrated that forkhead box protein M1 (FoxM1) was directly regulated by miR‑320a. Rescue experiments in vitro revealed that the upregulation of FoxM1 antagonized the miR‑320a‑mediated malignant phenotype in renal cancer. Furthermore, experiments employing a xenograft mouse model revealed that the upregulation of miR‑320a inhibited the proliferation of renal cancer cells in nude mice when FoxM1 protein expression was reduced. Collectively, the present study demonstrated a novel molecular interaction regulated by miR‑320a, which may provide a novel insight into the treatments for renal cancer.

Targeting forkhead box M1 transcription factor in breast cancer

Breast cancer continues to be the most commonly diagnosed malignancy and second most common cause of cancer-related deaths among women in the United States. Improved understanding of the molecular heterogeneity of breast tumors and the approval of multiple targeted therapies have revolutionized the treatment landscape and long-term survival rates for patients with breast cancer. Despite the development of highly effective targeted agents, drug resistance and disease progression remain major clinical concerns. Improved understanding of the molecular mechanisms mediating drug resistance will allow new treatments to be developed. The forkhead box M1 (FoxM1) transcription factor is overexpressed in breast cancer and strongly associated with resistance to targeted therapies and chemotherapy. FoxM1 regulates all hallmarks of cancer, including proliferation, mitosis, EMT, invasion, and metastasis. Inhibition of FoxM1 transcription factor function is a potential strategy for overcoming breast cancer progression. In this research update, we review the role of FoxM1 in breast cancer and pharmacological approaches for blocking FoxM1 transcription factor function. Future preclinical studies should evaluate combination drug strategies to inhibit FoxM1 function and upstream kinase signaling pathways as potential strategies to treat resistant and metastatic breast cancers.

FOXK2 suppresses the malignant phenotype and induces apoptosis through inhibition of EGFR in clear-cell renal cell carcinoma

Forkhead box K2 (FOXK2) belongs to the forkhead box transcription factor family. Recent studies have revealed that FOXK2 plays essential roles in cancer cell proliferation and survival. However, the biological function of FOXK2 in renal cell carcinoma remains unexplored. In our study, we demonstrated that FOXK2 mRNA and protein levels were decreased in clear-cell renal cell carcinoma (ccRCC) tissues compared to those in corresponding non-tumor renal tissues, and decreased FOXK2 levels were associated with poor prognosis in ccRCC patients after nephrectomy. FOXK2 suppressed proliferation, migration and invasion capabilities of ccRCC cells and induced cellular apoptosis in vitro. Moreover, we found that FOXK2 overexpression inhibited xenograft tumor growth and promoted apoptosis in vivo. Genome-wide transcriptome profiling using FOXK2 overexpressed 769-P cells revealed that the epidermal growth factor receptor (EGFR) was a potential downstream gene of FOXK2. Overexpression of EGFR is able to rescue the inhibited proliferation capacity and the enhanced apoptosis capacity due to the overexpression of FOXK2 in 769-P cells. Collectively, our results indicate that FOXK2 inhibits the malignant phenotype of ccRCC and acts as a tumor suppressor possibly through the inhibition of EGFR.

LncRNA LOC653786 promotes growth of RCC cells via upregulating FOXM1

Renal cell carcinoma (RCC) is the most common kidney malignancy with poor prognosis. Recently, long noncoding RNAs (lncRNAs) have been demonstrated as important regulators in multiple cancers including RCC. LOC653786 is a lncRNA, but its role in cancer remains unclear. In this study, we for the first time found that LOC653786 was upregulated in RCC tissues and cell lines, and this lncRNA promoted growth and cell cycle progression of RCC cells. Moreover, we showed that LOC653786 elevated the expression of forkhead box M1 (FOXM1) and its downstream target genes cyclin D1 and cyclin B1 in RCC cells. Reporter assay revealed that LOC653786 enhanced the transcriptional activity of FOXM1 gene promoter. Additionally, knockdown of FOXM1 attenuated the LOC653786-enhanced growth and cell cycle progression of RCC cells. Meanwhile, silencing of LOC653786 suppressed RCC cell growth and cell cycle progression, which was alleviated by overexpression of FOXM1. The in vivo experiments in nude mice showed knockdown of LOC653786 repressed xenograft tumor growth and FOXM1 expression. In conclusion, our results demonstrate that LOC653786 accelerates growth and cell cycle progression of RCC cells via upregulating FOXM1, suggesting that the ‘LOC653786/FOXM1’ pathway may serve as a novel target for RCC treatment.

The FOXM1/BUB1B signaling pathway is essential for the tumorigenicity and radioresistance of glioblastoma

Accumulating evidence indicates that mitotic checkpoint serine/threonine kinase B (BUB1B) plays a critical role in multiple types of cancer. However, the biological function and molecular regulatory mechanism of BUB1B in glioblastoma (GBM) remain unclear. In the present study, we identified that BUB1B expression was enriched in GBM tumors and was functionally required for tumor proliferation both in vitro and in vivo. Clinically, BUB1B expression was associated with poor prognosis in GBM patients and BUB1B-dependent radioresistance in GBM was decreased by targeting BUB1B via shRNAs. Mechanistically, forkhead box protein M1 (FOXM1) transcriptionally regulated BUB1B expression by binding to and then activating the BUB1B promoter. Therapeutically, we found that FOXM1 inhibitor attenuated tumorigenesis and radioresistance of GBM both in vitro and in vivo. Altogether, BUB1B promotes tumor proliferation and induces radioresistance in GBM, indicating that BUB1B could be a potential therapeutic target for GBM.

miR-216b inhibits glioma cell migration and invasion through suppression of FoxM1

MicroRNAs (miRNAs) play a vital role in tumour biological and pathologic processes. In the present study, we aimed to detect the expression and biological role of miR-216b in glioma. Our data showed that miR-216b was significantly downregulated in human glioma tissues and cells. Ectopic expression of miR-216b inhibited the proliferation and invasion of U87 and U251 cells and suppressed the growth of xenograft tumours in vivo. Bioinformatic and luciferase reporter analyses identified Forkhead box protein M1 (FoxM1) as a direct target of miR-216b. Overexpression of miR-216b inhibited the expression of FoxM1 in glioma cells. Rescue experiments demonstrated that co-transfection of FoxM1 lacking the 3'-untranslated region partially prevented miR‑216b-induced inhibition of glioma cell growth and invasion. In vivo studies indicated that ectopic expression of miR-216b impeded the proliferation of glioma xenograft tumours in nude mice, coupled with a decreased in FoxM1 protein expression and the percentage of Ki-67-positive tumour cells. Taken together, our results provide evidence of the suppressive activity of miR‑216b in glioma, which is largely ascribed to downregulation of FoxM1. Restoration of miR-216b may provide a novel potential therapeutic agent for glioma.

Tetramethylpyrazine inhibits prostate cancer progression by downregulation of forkhead box M1

Tetramethylpyrazine (TMP) has exhibited various anticancer effects. However, its ability to inhibit proliferation, migration, and invasion of prostate cancer (PCa) PC-3 cells is still unclear. In the present study, different concentrations of TMP were co-incubated with PC-3 cells. The pcDNA-FOXM1 plasmid was transfected into cells before treatment with 500 µg/l TMP. The proliferative, migratory and invasive abilities of PC-3 cells were tested by MTT assay, wound healing assay and colony formation assay. Western blotting was used to investigate the expression of FOXM1. We found that, compared with the control, the proliferative, migratory and invasive abilities of PC-3 cells were decreased after incubation with different concentrations of TMP (P<0.01). The expression of FOXM1 was decreased in TMP-treated PC-3 cells (P<0.01). In addition, overexpression of FOXM1 reversed TMP-mediated inhibition of proliferation, migration and invasion of PC-3 cells. We also found that TMP inhibited PCa growth in vivo in a dose-dependent manner. These results suggest that TMP inhibits PC-3 cell proliferation, migration and invasion by downregulation of FOXM1.

Tanshinone IIA suppresses gastric cancer cell proliferation and migration by downregulation of FOXM1

Tanshinone IIA (TSN) exhibits a variety of anticancer effects. However, whether it inhibits gastric cancer (GC) cell proliferation and migration and the mechanism remain unclear. In the present study, different concentrations of TSN were co-incubated with SGC-7901 cells. The pcDNA-FOXM1 or FOXM1-siRNA plasmid was transfected into cells before treatment with 5 µg/l TSN. The proliferation and migration abilities of the SGC-7901 cells were tested by MTT and wound healing assays. Western blotting was used to investigate the expression levels of P21, Ki-67, PCNA, MMP-2, MMP-9 and FOXM1. We found that compared with the control, the proliferation and migration abilities of the SGC-7901 cells were decreased after incubation with different concentrations of TSN in a dose-dependent manner (p<0.01). Moreover, the expression levels of Ki-67, PCAN, MMP-2, MMP-9 and FOXM1 were decreased, and P21 was increased in the TSN-treated SGC-7901 cells (p<0.01). In addition, downregulation of FOXM1 by FOXM1-siRNA had the same effect as TSN on SGC-7901 cells, and overexpression of FOXM1 partly abrogated TSN-mediated inhibition of SGC-7901 cell proliferation and migration. These results suggested that TSN inhibits SGC-7901 cell proliferation and migration by downregulation of FOXM1.

PLK1, A Potential Target for Cancer Therapy

Polo-like kinase 1 (PLK1) plays an important role in the initiation, maintenance, and completion of mitosis. Dysfunction of PLK1 may promote cancerous transformation and drive its progression. PLK1 overexpression has been found in a variety of human cancers and was associated with poor prognoses in cancers. Many studies have showed that inhibition of PLK1 could lead to death of cancer cells by interfering with multiple stages of mitosis. Thus, PLK1 is expected to be a potential target for cancer therapy. In this article, we examined PLK1’s structural characteristics, its regulatory roles in cell mitosis, PLK1 expression, and its association with survival prognoses of cancer patients in a wide variety of cancer types, PLK1 interaction networks, and PLK1 inhibitors under investigation. Finally, we discussed the key issues in the development of PLK1-targeted cancer therapy.

PLK1 promotes epithelial-mesenchymal transition and metastasis of gastric carcinoma cells

Cancer cell epithelial-mesenchymal transition (EMT) is the crucial event for cancer progression and plays a vital role in the metastasis of cancer cells. Activation of Polo-like kinase 1 (PLK1) signaling has been implicated as the critical event in several tumor metastasis and EMT, however, whether PLK1 participates in gastric carcinoma metastasis and EMT still remains unclear. For this study, we elucidated the potential physiological function of PLK1 in the metastasis of gastric tumors, as well its distinct role in cells EMT and subsequently determined the mechanism involved in PLK1 regulated. Immunoblotting assay and Oncomine data mining analysis indicated that PLK1 expression was highly up-regulated in gastric carcinoma. Kaplan-Meier survival analysis for the relationship between survival outcomes and PLK1 expression in gastric carcinoma was performed with an online Kaplan-Meier plotter (http://kmplot.com/analysis/). Over-expression of PLK1 in gastric cancer cells SGC-7901 and MKN-28 significantly promoted cells profound morphological changes and enhanced metastatic ability of tumor cells. On the contrary, silencing of PLK1 induced mesenchymal epithelial transition (MET)-like morphological and inhibited the metastatic process. Furthermore, we found that the metastatic characters promoting effects of PLK1 in gastric carcinoma was related to the activation of protein kinase B (AKT). Our mechanistic investigations revealed that AKT inhibition reversed PLK1-induced EMT, blocked gastric carcinoma cells invasiveness and metastasis. Additionally, over-expression of AKT promoted the migratory and invasion ability of the two cell lines, which was disrupted by PLK1 down-regulation. To conclude, our findings demonstrate that PLK1 accelerates the metastasis and epithelial-mesenchyme transition of gastric cancer cells through regulating the AKT pathway.