FOXM1 confers to epithelial-mesenchymal transition, stemness and chemoresistance in epithelial ovarian carcinoma cells

Expression of Forkhead Box M1 and Anticancer Effects of FOXM1 Inhibition in Epithelioid Sarcoma

Epithelioid sarcoma (ES) is a rare aggressive sarcoma that, unlike most soft-tissue sarcomas, shows a tendency toward local recurrence and lymph node metastasis. Novel antitumor agents are needed for ES patients. Forkhead box transcription factor 1 (FOXM1) is a member of the Forkhead transcription factor family and is associated with multiple oncogenic functions; FOXM1 is known to be overexpressed and correlated with pathogenesis in various malignancies. In this study, we immunohistochemically analyzed FOXM1 expression levels and their clinical, clinicopathologic, and prognostic significance in 38 ES specimens. In addition, to investigate potential correlations between FOXM1 downregulation and oncologic characteristics, we treated ES cell lines with thiostrepton, a naturally occurring antibiotic that inhibits both small interfering RNA (siRNA) and FOXM1. In the analyses using ES samples, all 38 specimens were diagnosed as positive for FOXM1 by immunohistochemistry. We separated specimens into high (n = 19) and low (n = 19) FOXM1-protein expression groups by staining index score, and into large (n = 12), small (n = 25), and unknown (n = 1) tumor-size groups using a cutoff of 5 cm maximum diameter. Although there were significantly more samples with high FOXM1 expression in the large tumor group (P = .013), there were no significant differences with respect to age (P = 1.00), sex (P = .51), primary site of origin (P = .74), histologic subtypes (P = 1.00), depth (P = .74), or survival rate (P = .288) between the high and low FOXM1-protein expression groups. In the in vitro experiments using ES cell lines, FOXM1 siRNA and thiostrepton successfully downregulated FOXM1 mRNA and protein expression. Furthermore, downregulation of FOXM1 inhibited cell proliferation, drug resistance against chemotherapeutic agents, migration, and invasion and caused cell cycle arrest in the ES cell lines. Finally, cDNA microarray analysis data showed that FOXM1 regulated cIAP2, which is one of the apoptosis inhibitors activated by the TNFα-mediated NF-κB pathway. In conclusion, the FOXM1 gene may be a promising therapeutic target for ES.

Wnt signaling and tumors (Review)

Wnt signaling is a highly conserved evolutionary pathway that plays a key role in regulation of embryonic development, as well as tissue homeostasis and regeneration. Abnormalities in Wnt signaling are associated with tumorigenesis and development, leading to poor prognosis in patients with cancer. However, the pharmacological effects and mechanisms underlying Wnt signaling and its inhibition in cancer treatment remain unclear. In addition, potential side effects of inhibiting this process are not well understood. Therefore, the present review outlines the role of Wnt signaling in tumorigenesis, development, metastasis, cancer stem cells, radiotherapy resistance and tumor immunity. The present review further identifies inhibitors that target Wnt signaling to provide a potential novel direction for cancer treatment. This may facilitate early application of safe and effective drugs targeting Wnt signaling in clinical settings. An in-depth understanding of the mechanisms underlying inhibition of Wnt signaling may improve the prognosis of patients with cancer.

Tumor microenvironment-induced FOXM1 regulates ovarian cancer stemness

In ovarian tumors, the omental microenvironment profoundly influences the behavior of cancer cells and sustains the acquisition of stem-like traits, with major impacts on tumor aggressiveness and relapse. Here, we leverage a patient-derived platform of organotypic cultures to study the crosstalk between the tumor microenvironment and ovarian cancer stem cells. We discovered that the pro-tumorigenic transcription factor FOXM1 is specifically induced by the microenvironment in ovarian cancer stem cells, through activation of FAK/YAP signaling. The microenvironment-induced FOXM1 sustains stemness, and its inactivation reduces cancer stem cells survival in the omental niche and enhances their response to the PARP inhibitor Olaparib. By unveiling the novel role of FOXM1 in ovarian cancer stemness, our findings highlight patient-derived organotypic co-cultures as a powerful tool to capture clinically relevant mechanisms of the microenvironment/cancer stem cells crosstalk, contributing to the identification of tumor vulnerabilities.

Recent advances on CAR-T signaling pave the way for prolonged persistence and new modalities in clinic

Chimeric antigen receptor T-cell (CAR-T) therapy has revolutionized the treatment of hematological malignancies. The importance of the receptor costimulatory domain for long-term CAR-T cell engraftment and therapeutic efficacy was demonstrated with second-generation CAR-T cells. Fifth generation CAR-T cells are currently in preclinical trials. At the same time, the processes that orchestrate the activation and differentiation of CAR-T cells into a specific phenotype that predisposes them to long-term persistence are not fully understood. This review highlights ongoing research aimed at elucidating the role of CAR domains and T-cell signaling molecules involved in these processes.

The Promise of Combination Therapies with FOXM1 Inhibitors for Cancer Treatment

Forkhead box M1 (FOXM1) is a transcription factor in the forkhead (FOX) family, which is required for cellular proliferation in normal and neoplastic cells. FOXM1 is highly expressed in many different cancers, and its expression is associated with a higher tumor stage and worse patient-related outcomes. Abnormally high expression of FOXM1 in cancers compared to normal tissue makes FOXM1 an attractive target for pharmacological inhibition. FOXM1-inhibiting agents and specific FOXM1-targeted small-molecule inhibitors have been developed in the lab and some of them have shown promising efficacy and safety profiles in mouse models. While the future goal is to translate FOXM1 inhibitors to clinical trials, potential synergistic drug combinations can maximize anti-tumor efficacy while minimizing off-target side effects. Hence, we discuss the rationale and efficacy of all previously studied drug combinations with FOXM1 inhibitors for cancer therapies.

High-grade serous ovarian carcinoma, the "Achiles' hill" for clinicians and molecular biologists: a molecular insight

High-grade serous ovarian carcinoma (HGSOC), the deadliest ovarian cancer, alone accounts for 90% of all its subtypes. Characterized by hallmark mutation of TP53, HGSOC show diverse molecular etiology. HGSOC can arise from both ovarian epithelium as well as the fimbrial epithelium of the fallopian tube. Ovulation induced reactive oxygen species, follicular fluid associated growth factor induced stemness, deregulation of hormone receptors like ER, FSHR, AR and hormones like FSH, LH, prolonged ovulation cycle, use of oral contraceptives are agonists of HGSOC while parity, breastfeeding provide protective effect from HGSOC development. Apart from a generic TP53 mutation, mutation of BRCA1/2, RAD51, BRIP1, PALB2, CHEK2, RAD50 etc., were reportedly associated with development of HGSOC. Epigenetic events like methylation of RASSF1A of RAS signaling pathway,OR51L1, OR51I1, OR51F1 etc. has been reported in HGSOC. Micro-RNAs like miR-1290, miR 27-a-3p miR23a, miR205 were reportedly upregulated in HGSOC. Amongst its cognate subtypes viz. differentiated, immunoreactive, mesenchymal, and proliferative, mesenchymal, and proliferative show worst prognosis. A system biology approach showed five major altered pathways in HGSOC, namely, RB, PI3K/RAS, NOTCH, HRR and FOXM1 signaling. For chemonaive patients, drugs that helps in efflux of reduced glutathione or prevent the redox coupling of GSH-GSSG, like Cisplatin, could be considered as the best therapeutic choice for HGSOC. For patients with BRCA1/2 mutations, PARP inhibitors alone or with Bevacizumab can be effective. Immune checkpoint inhibitors could be effective against immunoreactive subtypes. Identification of genes deregulated in chemoresistance could provide better insights in dealing with the disease.

Forkhead box proteins as the critical regulators of cisplatin response in tumor cells

Cisplatin (CDDP) is one of the most common chemotherapy drugs used in a wide range of cancer patients; however, there is a high rate of CDDP resistance among cancer patients. Considering the side effects of cisplatin in normal tissues, it is necessary to predict the CDDP response in cancer patients. Therefore, identifying the molecular mechanisms involved in CDDP resistance can help to introduce the prognostic markers. Several molecular mechanisms such as apoptosis inhibition, drug efflux, drug detoxification, and increased DNA repair are involved in CDDP resistance. Regarding the key role of transcription factors in regulation of many cellular processes related to drug resistance, in the present review, we discussed the role of Forkhead box (FOX) protein family in CDDP response. It has been reported that FOX proteins mainly promote CDDP resistance through the regulation of DNA repair, autophagy, epithelial-mesenchymal transition (EMT), and signaling pathways. Therefore, FOX proteins can be introduced as the prognostic markers to predict CDDP response in cancer patients. In addition, considering that oncogenic role of FOX proteins, the CDDP treatment along with FOX inhibition can be used as a therapeutic strategy in cancer patients.

Role of forkhead box proteins in regulation of doxorubicin and paclitaxel responses in tumor cells: A comprehensive review

Chemotherapy is one of the common first-line therapeutic methods in cancer patients. Despite the significant effects in improving the quality of life and survival of patients, chemo resistance is observed in a significant part of cancer patients, which leads to tumor recurrence and metastasis. Doxorubicin (DOX) and paclitaxel (PTX) are used as the first-line drugs in a wide range of tumors; however, DOX/PTX resistance limits their use in cancer patients. Considering the DOX/PTX side effects in normal tissues, identification of DOX/PTX resistant cancer patients is required to choose the most efficient therapeutic strategy for these patients. Investigating the molecular mechanisms involved in DOX/PTX response can help to improve the prognosis in cancer patients. Several cellular processes such as drug efflux, autophagy, and DNA repair are associated with chemo resistance that can be regulated by transcription factors as the main effectors in signaling pathways. Forkhead box (FOX) family of transcription factor has a key role in regulating cellular processes such as cell differentiation, migration, apoptosis, and proliferation. FOX deregulations have been associated with resistance to chemotherapy in different cancers. Therefore, we discussed the role of FOX protein family in DOX/PTX response. It has been reported that FOX proteins are mainly involved in DOX/PTX response by regulation of drug efflux, autophagy, structural proteins, and signaling pathways such as PI3K/AKT, NF-kb, and JNK. This review is an effective step in introducing the FOX protein family as the reliable prognostic markers and therapeutic targets in cancer patients.

FOXM1: A small fox that makes more tracks for cancer progression and metastasis

Transcription factors (TFs) are indispensable for the modulation of various signaling pathways associated with normal cell homeostasis and disease conditions. Among cancer-related TFs, FOXM1 is a critical molecule that regulates multiple aspects of cancer cells, including growth, metastasis, recurrence, and stem cell features. FOXM1 also impact the outcomes of targeted therapies, chemotherapies, and immune checkpoint inhibitors (ICIs) in various cancer types. Recent advances in cancer research strengthen the cancer-specific role of FOXM1, providing a rationale to target FOXM1 for developing targeted therapies. This review compiles the recent studies describing the pivotal role of FOXM1 in promoting metastasis of various cancer types. It also implicates the contribution of FOXM1 in the modulation of chemotherapeutic resistance, antitumor immune response/immunotherapies, and the potential of small molecule inhibitors of FOXM1.

Machine learning-assisted analysis of epithelial mesenchymal transition pathway for prognostic stratification and immune infiltration assessment in ovarian cancer

Background

Ovarian cancer is the most lethal gynaecological malignancy, and serous ovarian cancer (SOC) is one of the more important pathological subtypes. Previous studies have reported a significant association of epithelial tomesenchymal transition (EMT) with invasive metastasis and immune modulation of SOC, however, there is a lack of prognostic and immune infiltration biomarkers reported for SOC based on EMT.

Methods

Gene expression data for ovarian cancer and corresponding patient clinical data were collected from the TCGA database and the GEO database, and cell type annotation and spatial expression analysis were performed on single cell sequencing data from the GEO database. To understand the cell type distribution of EMT-related genes in SOC single-cell data and the enrichment relationships of biological pathways and tumour functions. In addition, GO functional annotation analysis and KEGG pathway enrichment analysis were performed on mRNAs predominantly expressed with EMT to predict the biological function of EMT in ovarian cancer. The major differential genes of EMT were screened to construct a prognostic risk prediction model for SOC patients. Data from 173 SOC patient samples obtained from the GSE53963 database were used to validate the prognostic risk prediction model for ovarian cancer. Here we also analysed the direct association between SOC immune infiltration and immune cell modulation and EMT risk score. and calculate drug sensitivity scores in the GDSC database.In addition, we assessed the specific relationship between GAS1 gene and SOC cell lines.

Results

Single cell transcriptome analysis in the GEO database annotated the major cell types of SOC samples, including: T cell, Myeloid, Epithelial cell, Fibroblast, Endothelial cell, and Bcell. cellchat revealed several cell type interactions that were shown to be associated with EMT-mediated SOC invasion and metastasis. A prognostic stratification model for SOC was constructed based on EMT-related differential genes, and the Kapan-Meier test showed that this biomarker had significant prognostic stratification value for several independent SOC databases. The EMT risk score has good stratification and identification properties for drug sensitivity in the GDSC database.

Conclusions

This study constructed a prognostic stratification biomarker based on EMT-related risk genes for immune infiltration mechanisms and drug sensitivity analysis studies in SOC. This lays the foundation for in-depth clinical studies on the role of EMT in immune regulation and related pathway alterations in SOC. It is also hoped to provide effective potential solutions for early diagnosis and clinical treatment of ovarian cancer.

A Focused Review on Molecular Signalling Mechanisms of Ginsenosides Anti-Lung Cancer and Anti-inflammatory Activities

BACKGROUND

Ginseng (Panax ginseng Meyer) is a cultivated medicinal herb that has been widely available in the Asian region since the last century. Ginseng root is used worldwide in Oriental medicine. Currently, the global mortality and infection rates for lung cancer and inflammation are significantly increasing. Therefore, various preventative methods related to the activity of ginsenosides have been used for lung cancer as well as inflammation.

METHODS

Web-based searches were performed on Web of Science, Springer, PubMed, and Scopus. A cancer statistical analysis was also conducted to show the current ratio of affected cases and death from lung cancer around the world.

RESULTS

Ginsenosides regulate the enzymes that participate in tumor growth and migration, such as nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (p38 MAPK), c-Jun N-terminal kinase (JNK), extracellular signalregulated kinases 1/2 (ERK1/2), the gelatinase network metalloproteinase-2 (MMP-2/9) and activator protein 1 (AP-1). In addition, ginsenosides also possess anti-inflammatory effects by inhibiting the formation of proinflammatory cytokines (tumor necrosis factor-α) (TNF-α) and interleukin-1β (IL-1β) and controlling the activities of inflammatory signalling pathways, such as NF-κB, Janus kinase2/signal transducer, and activator of transcription 3 (Jak2/Stat3).

CONCLUSION

In several in vitro and in vivo models, P. ginseng showed potential beneficial effects in lung cancer and inflammation treatment. In this review, we provide a detailed and up-to-date summary of research evidence for antilung cancer and anti-inflammatory protective effects of ginsenosides and their potential molecular mechanisms.

Thiostrepton confers protection against reactive oxygen species-related apoptosis by restraining FOXM1-triggerred development of gastric cancer

Gastric cancer is a leading cause of tumor-associated death worldwide. Metastasis and chemoresistance are crucial barriers for gastric cancer treatment. The Forkhead Box M1 (FOXM1) transcription factor has been reported as a promising treatment target for various types of tumors, but its effects on gastric cancer progression are not fully understood. In the present study, we found that FOXM1 expression levels were significantly up-regulated in human gastric cancer cell lines and tissues, and its expression was much higher in patients with metastasis. We then found that suppressing FOXM1 with its inhibitor thiostrepton (THIO) significantly reduced the proliferation of gastric cancer cells, while induced G0/G1 and apoptosis. Moreover, reactive oxygen species (ROS) production, mitochondrial impair and autophagy were remarkably provoked in gastric cancer cells treated with THIO, which were required for the regulation of apoptotic cell death. Furthermore, THIO exposure considerably suppressed the migration, invasion and angiogenesis in gastric cancer cells. The inhibitory effects of THIO on tumor growth and metastasis were confirmed in an established gastric cancer xenograft mouse model without detectable toxicity. Intriguingly, our in vitro studies showed that the anti-cancer effects of THIO on gastric cancer were almost abolished upon FOXM1 over-expression, indicating the necessity of FOXM1 suppression in THIO-inhibited tumor growth. In addition, higher FOXM1 expression was detected in gastric cancer cells with chemoresistance. Both in vitro and in vivo studies illustrated that THIO strongly promoted the drug-resistant gastric cancer cells to chemotherapies, proved by the considerably decreased cell proliferation and epithelial-mesenchymal transition (EMT) process. Together, these findings revealed that FOXM1 was a promising therapeutic target for gastric cancer treatment, and THIO exerted potential as an therapeutic agent for the disease.

Dysregulated FOXM1 signaling in the regulation of cancer stem cells

Since the introduction of the cancer stem cell (CSC) paradigm, significant advances have been made in understanding the functional and biological plasticity of these elusive components in malignancies. Endowed with self-renewing abilities and multilineage differentiation potential, CSCs have emerged as cellular drivers of virtually all facets of tumor biology, including metastasis, tumor recurrence/relapse, and drug resistance. The functional and biological characteristics of CSCs, such as self-renewal, cell fate decisions, survival, proliferation, and differentiation are regulated by an array of extracellular factors, signaling pathways, and pluripotent transcriptional factors. Besides the well-characterized regulatory role of transcription factors OCT4, SOX2, NANOG, KLF4, and MYC in CSCs, evidence for the central role of Forkhead box transcription factor FOXM1 in the establishment, maintenance, and functions of CSCs is accumulating. Conventionally identified as a master regulator of the cell cycle, a comprehensive understanding of this molecule has revealed its multifarious oncogenic potential and uncovered its role in angiogenesis, invasion, migration, self-renewal, and drug resistance. This review compiles the large body of literature that has accumulated in recent years that provides evidence for the mechanisms by which FOXM1 expression promotes stemness in glioblastoma, breast, colon, ovarian, lung, hepatic, and pancreatic carcinomas. We have also compiled the data showing the association of stem cell mediators with FOXM1 using TCGA mRNA expression data. Further, the prognostic importance of FOXM1 and other stem cell markers is presented. The delineation of FOXM1-mediated regulation of CSCs can aid in the development of molecularly targeted pharmacological approaches directed at the selective eradication of CSCs in several human malignancies.

Stem cell like memory T cells: A new paradigm in cancer immunotherapy

Stem cell like memory T (T_SCM) cells have emerged as the apex of memory T cell differentiation for their properties of self-renewal and replenishing progenies. With potent long-term persistence, proliferative capacity and antitumor activity, T_SCM cells were thought to be the ideal candidate for cancer immunotherapies. Several strategies have been proposed, such as manipulations of cytokines, metabolic factors, signal pathways, and T cell receptor signal intensity, to induce more T_SCM cells in vitro, in the hope that they could reach a clinical order of magnitude to provide more long-lasting and effective anti-tumor effects in vivo. In this review, we summarized the differentiation characteristics of T_SCM cells and strategies to generate more T_SCM cells. We focused on their roles and application in the cancer immunotherapy especially in adoptive cell transfer therapy and cancer therapeutic vaccines, and hopefully provided clues for future understanding and researches.

FAT10 promotes chemotherapeutic resistance in pancreatic cancer by inducing epithelial-mesenchymal transition via stabilization of FOXM1 expression

Pancreatic cancer (PC) is one of the deadliest malignant tumors, and its resistance to gemcitabine chemotherapy is the primary reason for poor prognosis in patients. Ubiquitin-like protein FAT10 has recently been reported to promote tumor chemotherapy resistance. In this study, the expression of FAT10 in PC was significantly higher than that in adjacent noncancerous tissues. Increased expression of FAT10 in PC was related to a late TNM stage and decreased overall survival. Functional experiments revealed that downregulating the expression of FAT10 inhibits the proliferation and epithelial-mesenchymal transition (EMT) of PC cells, promotes the apoptosis of PC cells, and enhances sensitivity to gemcitabine chemotherapy. In addition, upregulation of FAT10 increased the expression of FOXM1 protein. The effect of downregulating FAT10 was reversed by FOXM1 overexpression, and FOXM1 knockdown inhibited EMT driven by FAT10 overexpression. Mechanistically, FAT10 stabilized the expression of FOXM1 by competing with ubiquitin to bind FOXM1 and inhibiting the ubiquitination-mediated degradation of FOXM1. In conclusion, the FAT10-FOXM1 axis is a pivotal driver of PC proliferation and gemcitabine resistance, and the results provide novel insights into chemotherapy resistance in PC.

KDM2B overexpression prevents myocardial ischemia‑reperfusion injury in rats through regulating inflammatory response via the TLR4/NF‑κB p65 axis

Histone modifier lysine-specific demethylase 2B (KDM2B) has been previously reported to activate the inflammatory response by transcription initiation of the IL-6 gene. However, the effects of KDM2B on the inflammatory response during myocardial ischemia-reperfusion (I/R) injury and corresponding mechanisms remain poorly understood. The present study aimed to investigate the role and mechanism of KDM2B in myocardial I/R injury. Therefore, a myocardial I/R injury model was established in rats through coronary artery ligation. Adeno-associated virus-encoding KDM2B and small interfering RNA-KDM2B were designed to determine the effects of KDM2B on myocardial I/R injury using H&E staining and a TUNEL assay in the myocardial tissues. Reverse transcription-quantitative PCR and western blotting were performed to detect the mRNA and protein expression levels of KDM2B, toll-like receptor 4 (TLR4), NF-κB p65 and NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3). ELISA was used to detect the levels of TNF-α, IL-6 and IL-1β in the peripheral blood samples. Pathological analysis demonstrated that the cells in the model group were disordered, with a large area of necrosis and neutrophil infiltration. Knocking down KDM2B expression significantly upregulated the mRNA and protein expression levels of TLR4, NLRP3, NF-κB p65 and the ratio of phosphorylated (p)-p65 to p65. KDM2B knockdown also significantly increased the levels of IL-1β, IL-6 and TNF-α in the peripheral blood, which aggravated myocardial injury and promoted the apoptosis of myocardial cells. However, overexpression of KDM2B downregulated the mRNA and protein expression levels of TLR4, NLRP3, NF-κB P65, the ratio of p-p65 to p65 whilst reducing the levels of IL-1β, IL-6 and TNF-α in the peripheral blood, which markedly improved myocardial injury and significantly inhibited the apoptosis of cells in myocardial tissue. In conclusion, the results indicated that overexpression of KDM2B may prevent myocardial I/R injury in rats by reducing the inflammatory response through regulation of the TLR4/NF-κB p65 axis.

Forkhead Box Protein M1 Promotes Nasopharyngeal Carcinoma Cell Tumorigenesis Possibly via the Wnt/β-Catenin Signaling Pathway

BACKGROUND Forkhead box protein M1 (FoxM1) is an important transcription factor involved in the development and progression of various malignancies. However, its role in nasopharyngeal carcinoma (NPC) remains largely unknown. This study aimed to assess the effect of FoxM1 on NPC cell tumorigenesis as well as the underlying mechanism. MATERIAL AND METHODS NPC cell lines CNE-1 and CNE-2 were treated with vehicle and FoxM1 inhibitor thiostrepton or transfected with small interfering RNA. CCK-8 assay, flow cytometric assay, and Hoechst 33258 staining were performed to assess the viability, apoptosis and nuclear morphological impairment, and cell cycle, respectively. The expression of apoptosis-related caspase-3 and caspase-9 was detected by western blot analysis The tumor growth in the mouse xenograft model of NPC treated with thiostrepton or control was assessed. The expression of Wnt/ß-catenin signaling proteins p27, FoxM1, S phase kinase-associated protein 2 (SKP2), and Cyclin D1 were determined both in cells and xenograft tissues by western blot analysis. RESULTS Inhibition of FoxM1 by thiostrepton significantly suppressed NPC cell viability, induced apoptosis, increased cell cycle arrest, impaired nuclear morphology, and reduced NPC cell-derived tumor xenograft growth. Mechanistically, inhibition or knockdown of FoxM1 inactivated the Wnt/ß-catenin signaling pathway, as demonstrated by altered expression of Wnt/ß-catenin signaling-related genes, including p27, SKP2, and cyclin D1, in both NPC cells and xenograft tissues. CONCLUSIONS We identified FoxM1 as a novel regulator of NPC cell tumorigenesis in vitro and in vivo. Targeting FoxM1 could be a promising therapeutic strategy against NPC.

Novel FOXM1 inhibitor identified via gene network analysis induces autophagic FOXM1 degradation to overcome chemoresistance of human cancer cells

FOXM1 transcription factor is an oncogene and a master regulator of chemoresistance in multiple cancers. Pharmacological inhibition of FOXM1 is a promising approach but has proven to be challenging. We performed a network-centric transcriptomic analysis to identify a novel compound STL427944 that selectively suppresses FOXM1 by inducing the relocalization of nuclear FOXM1 protein to the cytoplasm and promoting its subsequent degradation by autophagosomes. Human cancer cells treated with STL427944 exhibit increased sensitivity to cytotoxic effects of conventional chemotherapeutic treatments (platinum-based agents, 5-fluorouracil, and taxanes). RNA-seq analysis of STL427944-induced gene expression changes revealed prominent suppression of gene signatures characteristic for FOXM1 and its downstream targets but no significant changes in other important regulatory pathways, thereby suggesting high selectivity of STL427944 toward the FOXM1 pathway. Collectively, the novel autophagy-dependent mode of FOXM1 suppression by STL427944 validates a unique pathway to overcome tumor chemoresistance and improve the efficacy of treatment with conventional cancer drugs.

A YAP/FOXM1 axis mediates EMT-associated EGFR inhibitor resistance and increased expression of spindle assembly checkpoint components

Acquired resistance to tyrosine kinase inhibitors (TKIs) of epidermal growth factor receptor (EGFR) remains a clinical challenge. Especially challenging are cases in which resistance emerges through EGFR-independent mechanisms, such as through pathways that promote epithelial-to-mesenchymal transition (EMT). Through an integrated transcriptomic, proteomic, and drug screening approach, we identified activation of the yes-associated protein (YAP) and forkhead box protein M1 (FOXM1) axis as a driver of EMT-associated EGFR TKI resistance. EGFR inhibitor resistance was associated with broad multidrug resistance that extended across multiple chemotherapeutic and targeted agents, consistent with the difficulty of effectively treating resistant disease. EGFR TKI-resistant cells displayed increased abundance of spindle assembly checkpoint (SAC) proteins, including polo-like kinase 1 (PLK1), Aurora kinases, survivin, and kinesin spindle protein (KSP). Moreover, EGFR TKI-resistant cells exhibited vulnerability to SAC inhibitors. Increased activation of the YAP/FOXM1 axis mediated an increase in the abundance of SAC components in resistant cells. The clinical relevance of these finding was indicated by evaluation of specimens from patients with EGFR mutant lung cancer, which showed that high FOXM1 expression correlated with expression of genes encoding SAC proteins and was associated with a worse clinical outcome. These data revealed the YAP/FOXM1 axis as a central regulator of EMT-associated EGFR TKI resistance and that this pathway, along with SAC components, are therapeutic vulnerabilities for targeting this multidrug-resistant phenotype.

FOXM1: A Multifunctional Oncoprotein and Emerging Therapeutic Target in Ovarian Cancer

Forkhead box M1 (FOXM1) is a member of the conserved forkhead box (FOX) transcription factor family. Over the last two decades, FOXM1 has emerged as a multifunctional oncoprotein and a robust biomarker of poor prognosis in many human malignancies. In this review article, we address the current knowledge regarding the mechanisms of regulation and oncogenic functions of FOXM1, particularly in the context of ovarian cancer. FOXM1 and its associated oncogenic transcriptional signature are enriched in >85% of ovarian cancer cases and FOXM1 expression and activity can be enhanced by a plethora of genomic, transcriptional, post-transcriptional, and post-translational mechanisms. As a master transcriptional regulator, FOXM1 promotes critical oncogenic phenotypes in ovarian cancer, including: (1) cell proliferation, (2) invasion and metastasis, (3) chemotherapy resistance, (4) cancer stem cell (CSC) properties, (5) genomic instability, and (6) altered cellular metabolism. We additionally discuss the evidence for FOXM1 as a cancer biomarker, describe the rationale for FOXM1 as a cancer therapeutic target, and provide an overview of therapeutic strategies used to target FOXM1 for cancer treatment.

Inactivation of the Akt/FOXM1 Signaling Pathway by Panobinostat Suppresses the Proliferation and Metastasis of Gastric Cancer Cells

Gastric cancer is the fifth most common cancer and the third leading cause of cancer-related deaths worldwide. Histone deacetylase (HDAC) inhibitors are a new class of cytostatic agents available for the treatment of various cancers and diseases. Although numerous clinical and pre-clinical trials on the anticancer effects of panobinostat have been conducted, only a few reports have investigated its efficacy in gastric cancer. The present study aimed to investigate the effects of panobinostat in gastric cancer cells. Panobinostat significantly inhibited the cell viability and proliferation of the gastric cancer cell lines SNU484 and SNU638 in a dose-dependent manner; it reduced the colony-forming ability of these cells. Moreover, it induced apoptosis as indicated by increased protein levels of cleaved poly ADP-ribose polymerase and cleaved caspase-3. Panobinostat induced the G2/M cell cycle arrest in SNU484 and SNU638 cells and subsequently decreased the G2/M phase regulatory-associated protein expression of p-Wee1, Myt1, and Cdc2. Furthermore, panobinostat significantly inhibited the metastasis of SNU484 and SNU638 cells by regulating the expression of MMP-9 and E-cadherin. Further, it decreased the protein levels of p-Akt and forkhead box protein M1 (FOXM1). These effects were reversed by the Akt agonist SC79 and were accelerated by the Akt inhibitor LY2940002. Moreover, tumor growth in xenograft animal experiments was suppressed by panobinostat. These results indicated that panobinostat inhibits the proliferation, metastasis, and cell cycle progression of gastric cancer cells by promoting apoptosis and inactivating Akt/FOXM1 signaling. Cumulatively, our present study suggests that panobinostat is a potential drug for the treatment of gastric cancer.

FOXM1 repression increases mitotic death upon antimitotic chemotherapy through BMF upregulation

Inhibition of spindle microtubule (MT) dynamics has been effectively used in cancer treatment. Although the mechanisms by which MT poisons elicit mitotic arrest are fairly understood, efforts are still needed towards elucidating how cancer cells respond to antimitotic drugs owing to cytotoxicity and resistance side effects. Here, we identified the critical G2/M transcription factor Forkhead box M1 (FOXM1) as a molecular determinant of cell response to antimitotics. We found FOXM1 repression to increase death in mitosis (DiM) due to upregulation of the BCL-2 modifying factor (BMF) gene involved in anoikis, an apoptotic process induced upon cell detachment from the extracellular matrix. FOXM1 binds to a BMF intronic cis-regulatory element that interacts with both the BMF and the neighbor gene BUB1B promoter regions, to oppositely regulate their expression. This mechanism ensures that cells treated with antimitotics repress BMF and avoid DiM when FOXM1 levels are high. In addition, we show that this mechanism is partly disrupted in anoikis/antimitotics-resistant tumor cells, with resistance correlating with lower BMF expression but in a FOXM1-independent manner. These findings provide a stratification biomarker for antimitotic chemotherapy response.

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

Simple Summary

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

Abstract

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

Lotus leaf extract inhibits ER- breast cancer cell migration and metastasis

BACKGROUND

Patients with estrogen receptor negative (ER^-) breast cancer have poor prognosis due to high rates of metastasis. However, there is no effective treatment and drugs for ER^- breast cancer metastasis. Our purpose of this study was to evaluate the effect of lotus leaf alcohol extract (LAE) on the cell migration and metastasis of ER^- breast cancer.

METHODS

The anti-migratory effect of LAE were analyzed in ER^- breast cancer cells including SK-BR-3, MDA-MB-231 and HCC1806 cell lines. Cell viability assay, wound-healing assay, RNA-sequence analysis and immunoblotting assay were used to evaluate the cytotoxicity and anti-migratory effect of LAE. To further investigate the inhibitory effect of LAE on metastasis in vivo, subcutaneous xenograft and intravenous injection nude mice models were established. Lung and liver tissues were analyzed by the hematoxylin and eosin staining and immunoblotting assay.

RESULTS

We found that lotus LAE, not nuciferine, inhibited cell migration significantly in SK-BR-3, MDA-MB-231 and HCC1806 breast cancer cells, and did not affect viability of breast cancer cells. The anti-migratory effect of LAE was dependent on TGF-β1 signaling, while independent of Wnt signaling and autophagy influx. Intracellular H₂O₂ was involved in the TGF-β1-related inhibition of cell migration. LAE inhibited significantly the breast cancer cells metastasis in mice models. RNA-sequence analysis showed that extracellular matrix signaling pathways are associated with LAE-suppressed cell migration.

CONCLUSIONS

Our findings demonstrated that lotus leaf alcohol extract inhibits the cell migration and metastasis of ER^- breast cancer, at least in part, via TGF-β1/Erk1/2 and TGF-β1/SMAD3 signaling pathways, which provides a potential therapeutic strategy for ER^- breast cancer.

Role of STAT3 signaling transduction pathways in cancer stem cell-associated chemoresistance

Chemoresistance resulting from cancer stem cells (CSCs) and epithelial-mesenchymal transition (EMT) results in inconsistent chemotherapeutic efficacy. The co-existence of CSCs and the EMT allows cancer cells to interconvert between differentiated and stem-like states, a phenomenon known as cellular plasticity. Phosphorylated signal transducer and activator of transcription 3 (pSTAT3) has been increasingly identified as a major contributor to CSCs and the EMT, as evidenced from preclinical studies that reversed chemoresistance through STAT3 pathway inhibition. In this review, we discuss mechanisms that center on STAT3 and its target genes responsible for regulating the EMT. We also highlight the current status of clinical trials using STAT3 pathway inhibitors.

The forkhead box M1 (FOXM1) expression and antitumor effect of FOXM1 inhibition in malignant rhabdoid tumor

PURPOSE

Malignant rhabdoid tumor (MRT) is a rare, highly aggressive sarcoma with an uncertain cell of origin. Despite the existing standard of intensive multimodal therapy, the prognosis of patients with MRT is very poor. Novel antitumor agents are needed for MRT patients. Forkhead box transcription factor 1 (FOXM1) is overexpressed and is correlated with the pathogenesis in several human malignancies. In this study, we identified the clinicopathological and prognostic values of the expression of FOXM1 and its roles in the progression of MRT.

METHODS

We investigated the FOXM1 expression levels and their clinical significance in 23 MRT specimens using immunohistochemistry and performed clinicopathologic and prognostic analyses. We also demonstrated correlations between the downregulation of FOXM1 and oncological characteristics using small interfering RNA (siRNA) and FOXM1 inhibitor in MRT cell lines.

RESULTS

Histopathological analyses revealed that primary renal MRTs showed significantly low FOXM1 protein expression levels (p = 0.032); however, there were no significant differences in other clinicopathological characteristics or the survival rate. FOXM1 siRNA and FOXM1 inhibitor (thiostrepton) successfully downregulated the mRNA and protein expression of FOXM1 in vitro and the downregulation of FOXM1 inhibited cell proliferation, drug resistance to chemotherapeutic agents, migration, invasion, and caused the cell cycle arrest and apoptosis of MRT cell lines. A cDNA microarray analysis showed that FOXM1 regulated FANCD2 and NBS1, which are key genes for DNA damage repair.

CONCLUSION

This study demonstrates that FOXM1 may serve as a promising therapeutic target for MRT.

DEAD-Box Helicase 4 (Ddx4)+ Stem Cells Sustain Tumor Progression in Non-Serous Ovarian Cancers

DEAD-Box Helicase 4 (Ddx4)⁺ ovarian stem cells are able to differentiate into several cell types under appropriate stimuli. Ddx4 expression has been correlated with poor prognosis of serous ovarian cancer (OC), while the potential role of Ddx4⁺ cells in non-serous epithelial OC (NS-EOC) is almost unexplored. The aim of this study was to demonstrate the presence of Ddx4⁺ cells in NS-EOC and investigate the effect of follicle-stimulating hormone (FSH) on this population. Increased Ddx4 expression was demonstrated in samples from patients with advanced NS-EOC, compared to those with early-stage disease. Under FSH stimulation, OC-derived Ddx4⁺ cells differentiated into mesenchymal-like (ML) cells, able to deregulate genes involved in cell migration, invasiveness, stemness and chemoresistance in A2780 OC cells. This effect was primarily induced by ML-cells deriving from advanced NS-EOC, suggesting that a tumor-conditioned germ cell niche inhabits its microenvironment and is able to modulate, in a paracrine manner, tumor cell behavior through transcriptome modulation.

MicroRNA-302 represses epithelial-mesenchymal transition and cisplatin resistance by regulating ATAD2 in ovarian carcinoma

Epithelial-mesenchymal transition (EMT) is an important contributor to drug resistance in ovarian cancer. The aims of this study were to explore the potential role of the miR-302 cluster in modulating EMT and cisplatin resistance in ovarian cancer. We used qRT-PCR and western blotting to show that miR-302 expression was lower in chemoresistant than in chemosensitive cells, and miR-302 was upregulated in chemosensitive, but not chemoresistant ovarian cancer cells in response to cisplatin treatment. We identified ATAD2 as a target of miR-302 and showed that ectopic expression of miR-302 increased cisplatin sensitivity and inhibited EMT and the invasiveness of cisplatin-resistant cells in vitro by targeting ATAD2. Knockdown of ATAD2 restored cisplatin sensitivity and reversed EMT/metastasis in cisplatin-resistant cells, as shown by western blotting and invasion/migration assays. The effect of miR-302 overexpression on EMT and invasiveness was mediated by the modulation of β-catenin nuclear expression. Immunofluorescence analysis showed that ATAD2 overexpression reversed the miR-302-induced downregulation of nuclear β-catenin in cisplatin resistant cells. A xenograft tumor model was used to show that miR-302 increases the antitumor effect of cisplatin in vivo. Taken together, these results identify a potential regulatory axis involving miR-302 and ATAD2 with a role in chemoresistance, indicating that activation of miR-302 or inactivation of ATAD2 could serve as a novel approach to reverse cisplatin resistance in ovarian cancer.

Tumor microenvironment and epithelial mesenchymal transition as targets to overcome tumor multidrug resistance

It is well established that multifactorial drug resistance hinders successful cancer treatment. Tumor cell interactions with the tumor microenvironment (TME) are crucial in epithelial-mesenchymal transition (EMT) and multidrug resistance (MDR). TME-induced factors secreted by cancer cells and cancer-associated fibroblasts (CAFs) create an inflammatory microenvironment by recruiting immune cells. CD11b+/Gr-1+ myeloid-derived suppressor cells (MDSCs) and inflammatory tumor associated macrophages (TAMs) are main immune cell types which further enhance chronic inflammation. Chronic inflammation nurtures tumor-initiating/cancer stem-like cells (CSCs), induces both EMT and MDR leading to tumor relapses. Pro-thrombotic microenvironment created by inflammatory cytokines and chemokines from TAMs, MDSCs and CAFs is also involved in EMT and MDR. MDSCs are the most common mediators of immunosuppression and are also involved in resistance to targeted therapies, e.g. BRAF inhibitors and oncolytic viruses-based therapies. Expansion of both cancer and stroma cells causes hypoxia by hypoxia-inducible transcription factors (e.g. HIF-1α) resulting in drug resistance. TME factors induce the expression of transcriptional EMT factors, MDR and metabolic adaptation of cancer cells. Promoters of several ATP-binding cassette (ABC) transporter genes contain binding sites for canonical EMT transcription factors, e.g. ZEB, TWIST and SNAIL. Changes in glycolysis, oxidative phosphorylation and autophagy during EMT also promote MDR. Conclusively, EMT signaling simultaneously increases MDR. Owing to the multifactorial nature of MDR, targeting one mechanism seems to be non-sufficient to overcome resistance. Targeting inflammatory processes by immune modulatory compounds such as mTOR inhibitors, demethylating agents, low-dosed histone deacetylase inhibitors may decrease MDR. Targeting EMT and metabolic adaptation by small molecular inhibitors might also reverse MDR. In this review, we summarize evidence for TME components as causative factors of EMT and anticancer drug resistance.

Pretreatment thrombocytosis as an independent predictive factor for chemoresistance and poor survival in epithelial ovarian cancer

BACKGROUND

Thrombocytosis is related to tumor stage and survival in ovarian cancer in addition to the common complications of malignant diseases, such as anemia and inflammation. The aim of our study was to clarify the precise prognostic impact of pretreatment thrombocytosis in epithelial ovarian cancer.

METHODS

We retrospectively analyzed 280 consecutive patients who were treated for epithelial ovarian cancer at our institution between 2001 and 2011.

RESULTS

Pretreatment thrombocytosis was observed in 18.9% of all patients and was associated with advanced FIGO stage, primary treatment, operation achievement, histologic subtype, microcytic hypochromic anemia (MHA), and nonmalignant inflammatory condition (P = 0.0018, 0.0028, 0.00050, 0.034, 0.00090 and 0.0022). In the patients who relapsed after primary adjuvant chemotherapy (n = 126), thrombocytosis was associated with a shorter treatment-free interval (TFI) (P = 0.0091). The univariate and multivariate analyses revealed that thrombocytosis was independently associated with TFI and MHA (P = 0.021 and 0.0091). Patients with thrombocytosis had worse progression-free survival (PFS) and overall survival (OS) than those without thrombocytosis (P <  0.0001 and <  0.0001). The multivariate analyses for prognostic factors demonstrated that thrombocytosis was significant for poor PFS and OS (P = 0.0050 and 0.022) independent of stage, histology, primary treatment, operation achievement, nonmalignant inflammatory condition and MHA.

CONCLUSIONS

The current findings indicate that the detrimental survival impact of pretreatment thrombocytosis in epithelial ovarian cancer may be independent of tumor extent but rather attributed to chemoresistance, further supporting the therapeutic potential of targeting thrombopoietic cytokines in the disease.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Ginsenosides Rk1 and Rg5 inhibit transforming growth factor-β1-induced epithelial-mesenchymal transition and suppress migration, invasion, anoikis resistance, and development of stem-like features in lung cancer

Background

Lung cancer has a high incidence worldwide, and most lung cancer-associated deaths are attributable to cancer metastasis. Although several medicinal properties of Panax ginseng Meyer have been reported, the effect of ginsenosides Rk1 and Rg5 on epithelial-mesenchymal transition (EMT) stimulated by transforming growth factor beta 1 (TGF- β1) and self-renewal in A549 cells is relatively unknown.

Methods

We treated TGF-β1 or alternatively Rk1 and Rg5 in A549 cells. We used western blot analysis, real-time polymerase chain reaction (qPCR), wound healing assay, Matrigel invasion assay, and anoikis assays to determine the effect of Rk1 and Rg5 on TGF-mediated EMT in lung cancer cell. In addition, we performed tumorsphere formation assays and real-time PCR to evaluate the stem-like properties.

Results

EMT is induced by TGF-β1 in A549 cells causing the development of cancer stem-like features. Expression of E-cadherin, an epithelial marker, decreased and an increase in vimentin expression was noted. Cell mobility, invasiveness, and anoikis resistance were enhanced with TGF-β1 treatment. In addition, the expression of stem cell markers, CD44, and CD133, was also increased. Treatment with Rk1 and Rg5 suppressed EMT by TGF-β1 and the development of stemness in a dose-dependent manner. Additionally, Rk1 and Rg5 markedly suppressed TGF-β1-induced metalloproteinase-2/9 (MMP2/9) activity, and activation of Smad2/3 and nuclear factor kappa B/extra-cellular signal regulated kinases (NF-kB/ERK) pathways in lung cancer cells.

Conclusions

Rk1 and Rg5 regulate the EMT inducing TGF-β1 by suppressing the Smad and NF-κB/ERK pathways (non-Smad pathway).

Chemoresistant ovarian cancer enhances its migration abilities by increasing store-operated Ca2+ entry-mediated turnover of focal adhesions

Background

Among gynecological cancers, ovarian carcinoma has the highest mortality rate, and chemoresistance is highly prevalent in this cancer. Therefore, novel strategies are required to improve its poor prognosis. Formation and disassembly of focal adhesions are regulated dynamically during cell migration, which plays an essential role in cancer metastasis. Metastasis is intricately linked with resistance to chemotherapy, but the molecular basis for this link is unknown.

Methods

Transwell migration and wound healing migration assays were used to analyze the migration ability of ovarian cancer cells. Real-time recordings by total internal reflection fluorescence microscope (TIRFM) were performed to assess the turnover of focal adhesions with fluorescence protein-tagged focal adhesion molecules. SOCE inhibitors were used to verify the effects of SOCE on focal adhesion dynamics, cell migration, and chemoresistance in chemoresistant cells.

Results

We found that mesenchymal-like chemoresistant IGROV1 ovarian cancer cells have higher migration properties because of their rapid regulation of focal adhesion dynamics through FAK, paxillin, vinculin, and talin. Focal adhesions in chemoresistant cells, they were smaller and exhibited strong adhesive force, which caused the cells to migrate rapidly. Store-operated Ca²⁺ entry (SOCE) regulates focal adhesion turnover, and cell polarization and migration. Herein, we compared SOCE upregulation in chemoresistant ovarian cancer cells to its parental cells. SOCE inhibitors attenuated the assembly and disassembly of focal adhesions significantly. Results of wound healing and transwell assays revealed that SOCE inhibitors decreased chemoresistant cell migration. Additionally, SOCE inhibitors combined with chemotherapeutic drugs could reverse ovarian cancer drug resistance.

Conclusion

Our findings describe the role of SOCE in chemoresistance-mediated focal adhesion turnover, cell migration, and viability. Consequently, SOCE might be a promising therapeutic target in epithelial ovarian cancer.

Graphical abstract

Glucose-Dependent FOXM1 Promotes Epithelial-to-Mesenchymal Transition Via Cellular Metabolism and Targeting Snail in Human Pancreatic Cancer

OBJECTIVES

Transcription factor Forkhead box protein M1 (FOXM1) plays critical roles in the progression of cancer including epithelial-to-mesenchymal transition (EMT). The aim of this study is to characterize the regulatory mechanisms of FOXM1 in EMT via pancreatic cancer metabolism.

METHODS

We investigated the regulation of EMT via mitochondrial respiration by FOXM1 using pancreatic cancer cell lines HPAC and PANC-1 and normal human pancreatic duct epithelial cells.

RESULTS

Forkhead box protein M1 and Snail were strongly expressed in HPAC and PANC-1. Epithelial-to-mesenchymal transition-modulated claudin-1 level was lower in PANC-1 than in HPAC. In both cell lines in low-glucose medium, FOXM1 and Snail were decreased and claudin-1 was increased. Knockdown of FOXM1 increased claudin-1 and decreased Snail in both cell lines. Low-glucose medium and downregulation of FOXM1 inhibited the cell migration in both cell lines. In both cell lines, mitochondrial respiration was at higher levels in low-glucose medium than in high-glucose medium. Downregulation of FOXM1 induced mitochondrial respiration in high-glucose medium. In normal human pancreatic duct epithelial cells, FOXM1 and Snail were low and claudin-1 was highly expressed, whereas overexpression of FOXM1 decreased claudin-1.

CONCLUSIONS

Glucose-dependent FOXM1 promoted EMT via Snail and pancreatic cancer metabolism.

HMGA Genes and Proteins in Development and Evolution

HMGA (high mobility group A) (HMGA1 and HMGA2) are small non-histone proteins that can bind DNA and modify chromatin state, thus modulating the accessibility of regulatory factors to the DNA and contributing to the overall panorama of gene expression tuning. In general, they are abundantly expressed during embryogenesis, but are downregulated in the adult differentiated tissues. In the present review, we summarize some aspects of their role during development, also dealing with relevant studies that have shed light on their functioning in cell biology and with emerging possible involvement of HMGA1 and HMGA2 in evolutionary biology.

Overexpression of PRC1 indicates a poor prognosis in ovarian cancer

Protein regulator of cytokinesis-1 (PRC1) is a microtubule-associated factor involved in cytokinesis. Recent studies have indicated that PRC1 overexpression is involved in tumorigenesis in multiple types of human cancer. However, the expression, biological functions and the prognostic significance of PRC1 in ovarian cancer have not yet been clarified. In this study, it was confirmed that the PRC1 mRNA and protein expression levels were upregulated in high-grade serous ovarian carcinoma (HGSOC) tissues, particularly in patients without breast cancer susceptibility gene (BRCA) pathogenic mutations. PRC1 overexpression contributed to drug resistance, tumor recurrence and a poor prognosis. The findings also indicated that PRC1 knockdown decreased the proliferation, metastasis and multidrug resistance of ovarian cancer cells in vitro. It was also demonstrated that forkhead box protein M1 (FOXM1) regulated the mRNA and protein expression of PRC1. Dual-luciferase reporter assay and rescue assay confirmed that PRC1 was a direct crucial downstream target of FOXM1. On the whole, the findings of this study confirmed that PRC1 was a major prognostic factor of HGSOC and a promising therapeutic biomarker for the treatment of ovarian cancer.

Disruption of crosstalk between LX-2 and liver cancer stem-like cells from MHCC97H cells by DFOG via inhibiting FOXM1

Hepatic stellate cell (HSC) line LX-2 is activated by liver cancer stem-like cells (LCSLCs) and produces various cytokines that make up most of the hepatocellular carcinoma (HCC) microenvironment. The new genistein derivative, 7-difluoromethoxyl-5,4'-di-n-octylgenistein (DFOG), shows anticancer effects in multiple malignancies by controlling forkhead box M1 (FOXM1). In this study, we aimed to assess whether DFOG disrupts the crosstalk between human HSC LX-2 cells and LCSLCs. Distinct generations of MHCC97H-derived spheres were obtained with the second generation considered as LCSLCs which displayed enhanced self-renewal ability and elevated expression levels of CD133, CD44, and EpCAM proteins, as well as tumorigenicity, as revealed by colony formation assay in vitro and tumorigenicity assay in vivo. LX-2 and MHCC97H cells were co-cultured with/without DFOG (1, 5, and 10 μM, respectively) using the transwell system. FOXM1 overexpression and/or knockdown were employed for mechanistic investigations. Our results suggested that Co-CM promoted LX-2 cell transformation into liver cancer-associated HSCs. Meanwhile, FOXM1 was up-regulated and the level of hepatocyte growth factor (HGF) was increased in LX-2 cells and in the supernatant after Co-CM stimulation. Sphere and colony formation abilities in MHCC97H cells, and protein levels of CD133, CD44, and EpCAM, were also markedly elevated. DFOG dose-dependently inhibited the above effects, similar to FOXM1 knockdown in LX-2 cells. FOXM1 overexpression reversed the inhibitory effects of DFOG or FOXM1 knockdown or both on LX-2 cell activation and LCSLC feature induction in MHCC97H cells by LCSLC/LX-2 co-culture. This study demonstrated that DFOG disrupts the crosstalk between HSCs and LCSLCs to suppress LCSLC features via down-regulating FOXM1 expression and reducing HGF secretion in HSCs.

Wnt/β-catenin signalling in ovarian cancer: Insights into its hyperactivation and function in tumorigenesis

Epithelial ovarian cancer (EOC) is the deadliest female malignancy. The Wnt/β-catenin pathway plays critical roles in regulating embryonic development and physiological processes. This pathway is tightly regulated to ensure its proper activity. In the absence of Wnt ligands, β-catenin is degraded by a destruction complex. When the pathway is stimulated by a Wnt ligand, β-catenin dissociates from the destruction complex and translocates into the nucleus where it interacts with TCF/LEF transcription factors to regulate target gene expression. Aberrant activation of this pathway, which leads to the hyperactivity of β-catenin, has been reported in ovarian cancer. Specifically, mutations of CTNNB1, AXIN, or APC, have been observed in the endometrioid and mucinous subtypes of EOC. In addition, upregulation of the ligands, abnormal activation of the receptors or intracellular mediators, disruption of the β-catenin destruction complex, inhibition of the association of β-catenin/E-cadherin on the cell membrane, and aberrant promotion of the β-catenin/TCF transcriptional activity, have all been reported in EOC, especially in the high grade serous subtype. Furthermore, several non-coding RNAs have been shown to regulate EOC development, in part, through the modulation of Wnt/β-catenin signalling. The Wnt/β-catenin pathway has been reported to promote cancer stem cell self-renewal, metastasis, and chemoresistance in all subtypes of EOC. Emerging evidence also suggests that the pathway induces ovarian tumor angiogenesis and immune evasion. Taken together, these studies demonstrate that the Wnt/β-catenin pathway plays critical roles in EOC development and is a strong candidate for the development of targeted therapies.

Differential Expression And Effects Of Peroxiredoxin-6 On Drug Resistance And Cancer Stem Cell-Like Properties In Non-Small Cell Lung Cancer

Objective

Cancer stem-like cells (CSC) are thought to be involved in the cisplatin resistance of tumors. This study was designed to investigate the effect of PRDX6 on CSCs present in cisplatin-resistant non-small cell lung cancer (NSCLC) tumors.

Materials and methods

CD133+/ABCG2+ H1299 CSCs and A549 CSCs were isolated. The IC₅₀ values for cisplatin in treatment of CSCs were detected using the CCK8 assay. Then the isolated cells were identified using CD133. Wnt/β-catenin expression was evaluated by Western blot assays. Specimens of tumor and adjacent para-carcinoma tissue were collected from 30 NSCLC patients and examined by immunohistochemistry (IHC), qRT-PCR, and Western blotting to determine and compare their levels of PRDX6 and CD133 expression. Finally, siRNA-mediated silencing of PRDX6 was employed with both types of CSCs to determine the impact of PRDX6 on CD133 enrichment by flow cytometry, cell viability, and sphere formation ability.

Results

High levels of PRDX6 and CD133 expression were detected in samples of tumor tissue from NSCLC patients, and expression of PRDX6 and CD13 presented a positive relationship. Increasing levels of cisplatin resistance and upregulated levels of PRDX6, ABCG2, Wnt, and β-catenin expression were detected in CD133+/ABCG2+ H1299 and A549 CSCs. Transfection with siRNA targeting PRDX6 changed these cellular characteristics by decreasing the levels of PRDX6, ABCG2, Wnt, and β-catenin expression. We further demonstrated that exogenous silencing of PRDX6 effectively inhibited the sphere formation ability of CSCs and re-sensitized them to cisplatin.

Conclusion

Our results strongly suggest that PRDX6 promotes cisplatin resistance in human lung cancer cells by promoting the stem-like properties of cancer cells. Our findings also suggest PRDX6 as a target for treating cisplatin resistant NSCLC.

Regulation of carcinogenesis and modulation through Wnt/β-catenin signaling by curcumin in an ovarian cancer cell line

The secreted frizzled-related protein 5 gene (SFRP5) that antagonize the Wnt/β-catenin signaling is frequently inactivated by promoter methylation and oncogenic activation of the Wnt signaling pathway is common in many cancers. The curcumin-rich Curcuma longa has been reported to potent anti-cancer property involved in epigenetic regulation to inhibit tumor suppressor gene methylation and re-expression. In a compounds screening, we found that curcumin can inhibit Wnt/β-catenin signaling. Therefore, the aim of this study was to investigate the effects of curcumin on SFRP5 DNA methylation modification in an ovarian cancer cell line (SKOV3). SKOV3 cells were treated with DMSO, 10 μM 5-aza-2′-deoxycytidine (DAC), 5 μM DAC, 20 μM curcumin, and 20 μM curcumin combined with 5 μM DAC for 96 hours, following which RNA and proteins were extracted for further analysis. The results showed that curcumin combined with 5 μM DAC may inhibit cancer cell colony formation, migration through EMT (epithelial–mesenchymal transition) process regulation, total DNMT activity, especially in DNMT3a protein expression, and may also regulate tumor suppressor gene SFRP5 expression involved in the Wnt/β-catenin signaling pathway. The combined treatment attenuated ovarian cancer development.

Identification of Potential Biomarkers in Association With Progression and Prognosis in Epithelial Ovarian Cancer by Integrated Bioinformatics Analysis

Epithelial ovarian cancer (EOC) is one of the malignancies in women, which has the highest mortality. However, the microlevel mechanism has not been discussed in detail. The expression profiles GSE27651, GSE38666, GSE40595, and GSE66957 including 188 tumor and 52 nontumor samples were downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) were filtered using R software, and we performed functional analysis using the clusterProfiler. Cytoscape software, the molecular complex detection plugin and database STRING analyzed DEGs to construct protein-protein interaction network. We identified 116 DEGs including 81 upregulated and 35 downregulated DEGs. Functional analysis revealed that they were significantly enriched in the extracellular region and biosynthesis of amino acids. We next identified four bioactive compounds (vorinostat, LY-294002,trichostatin A, and tanespimycin) based on ConnectivityMap. Then 114 nodes were obtained in protein-protein interaction. The three most relevant modules were detected. In addition, according to degree ≥ 10, 14 core genes including FOXM1, CXCR4, KPNA2, NANOG, UBE2C, KIF11, ZWINT, CDCA5, DLGAP5, KIF15, MCM2, MELK, SPP1, and TRIP13 were identified. Kaplan-Meier analysis, Oncomine, and Gene Expression Profiling Interactive Analysis showed that overexpression of FOXM1, SPP1, UBE2C, KIF11, ZWINT, CDCA5, UBE2C, and KIF15 was related to bad prognosis of EOC patients. CDCA5, FOXM1, KIF15, MCM2, and ZWINT were associated with stage. Receiver operating characteristic (ROC) curve showed that messenger RNA levels of these five genes exhibited better diagnostic efficiency for normal and tumor tissues. The Human Protein Atlas database was performed. The protein levels of these five genes were significantly higher in tumor tissues compared with normal tissues. Functional enrichment analysis suggested that all the hub genes played crucial roles in citrate cycle tricarboxylic acid cycle. Furthermore, the univariate and multivariate Cox proportional hazards regression showed that ZWINT was independent prognostic indictor among EOC patients. The genes and pathways discovered in the above studies may open a new direction for EOC treatment.

Outcome-Related Differences in Gene Expression Profiles of High-Grade Serous Ovarian Cancers Following Neoadjuvant Chemotherapy

Large-scale genomic studies have detailed the molecular landscape of tumors from patients with high-grade serous ovarian cancers (HGSC) who underwent primary debulking surgery and correlated the identified subgroups to survival. In recent years, there is increased use of neoadjuvant chemotherapy (NACT) for patients with HGSC and while abundant data exist for patients who underwent primary debulking, little data are available on the cancer cells remaining after NACT that could lead to recurrences. We aimed to analyze gene expression profiles of NACT-treated HGSC tumor samples, and correlate them to treatment response and outcome. Tumor samples were collected from patients with stage III or IV HGSC (NACT cohort, N = 57) at the time of surgery and diagnosis (biopsy samples N = 8). Tumor content was validated by histologic examination and bioinformatics. Gene expression analysis was performed using a tailored NanoString-based assay, while sequencing was performed using MiSeq. A cross-validated survival classifier revealed patient clusters with either a "Better" or "Worse" prognostic outcome. The association with overall survival remained significant after controlling for clinical variables, and differential gene expression, gene set enrichment analyses, and the appropriate survival models were used to assess the associations between alterations in gene expression in cancer cells remaining after NACT and outcome. Pathway-based analysis of the differentially expressed genes revealed comparatively high levels of cell cycle and DNA repair gene expression in the poor outcome group. IMPLICATIONS: Our work suggests mRNA expression patterns in key genes following NACT may reflect response to treatment and outcome in patient with HGSC.

Linking Cancer Metabolic Dysfunction and Genetic Instability through the Lens of Iron Metabolism

Iron (Fe) is an essential element that plays a fundamental role in a wide range of cellular functions, including cellular proliferation, DNA synthesis, as well as DNA damage and repair. Because of these connections, iron has been strongly implicated in cancer development. Cancer cells frequently have changes in the expression of iron regulatory proteins. For example, cancer cells frequently upregulate transferrin (increasing uptake of iron) and down regulate ferroportin (decreasing efflux of intracellular iron). These changes increase the steady-state level of intracellular redox active iron, known as the labile iron pool (LIP). The LIP typically contains approximately 2% intracellular iron, which primarily exists as ferrous iron (Fe²⁺). The LIP can readily contribute to oxidative distress within the cell through Fe²⁺-dioxygen and Fenton chemistries, generating the highly reactive hydroxyl radical (HO^•). Due to the reactive nature of the LIP, it can contribute to increased DNA damage. Mitochondrial dysfunction in cancer cells results in increased steady-state levels of hydrogen peroxide and superoxide along with other downstream reactive oxygen species. The increased presence of H₂O₂ and O₂^•- can increase the LIP, contributing to increased mitochondrial uptake of iron as well as genetic instability. Thus, iron metabolism and labile iron pools may play a central role connecting the genetic mutational theories of cancer to the metabolic theories of cancer.

Oxaliplatin reverses the GLP-1R-mediated promotion of intrahepatic cholangiocarcinoma by altering FoxO1 signaling

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver cancer, with a 5-year survival rate of <10%; effective drug treatment for ICC is currently lacking. Glucagon-like peptide-1 receptor (GLP-1R) is upregulated in ICC; however, the functions of GLP-1R in ICC remain unknown. In this study, the upregulation of GLP-1R was confirmed in ICC cells using reverse transcription-quantitative polymerase chain reaction and western blot analysis, and GLP-1R was determined to promote the migration and invasion of ICC cells using Transwell assays. This tumor-promoting effect depended on the upregulation of epithelial-mesenchymal transformation-associated proteins, which was mediated by the FoxO1 signaling pathway. It was also indicated that following oxaliplatin treatment, the effects of GLP-1R on EMT and invasion were reversed. This functional reversion was associated with the reduced phosphorylation of S256 in forkhead box O1 (FoxO1) and an increase in the levels of unphosphorylated FoxO1. These findings suggest that incretin-based therapies may increase the risk of ICC metastasis and should not be used solely for the treatment of patients with ICC.

The Role of Epithelial-to-Mesenchymal Plasticity in Ovarian Cancer Progression and Therapy Resistance

Ovarian cancer is the most lethal of all gynecologic malignancies and the eighth leading cause of cancer-related deaths among women worldwide. The main reasons for this poor prognosis are late diagnosis; when the disease is already in an advanced stage, and the frequent development of resistance to current chemotherapeutic regimens. Growing evidence demonstrates that apart from its role in ovarian cancer progression, epithelial-to-mesenchymal transition (EMT) can promote chemotherapy resistance. In this review, we will highlight the contribution of EMT to the distinct steps of ovarian cancer progression. In addition, we will review the different types of ovarian cancer resistance to therapy with particular attention to EMT-mediated mechanisms such as cell fate transitions, enhancement of cancer cell survival, and upregulation of genes related to drug resistance. Preclinical studies of anti-EMT therapies have yielded promising results. However, before anti-EMT therapies can be effectively implemented in clinical trials, more research is needed to elucidate the mechanisms leading to EMT-induced therapy resistance.