NF-kappaB and epithelial to mesenchymal transition of cancer

Plumbagin Suppresses the Invasion of HER2-Overexpressing Breast Cancer Cells through Inhibition of IKKα-Mediated NF-κB Activation

HER2-overexpressing breast cancers account for about 30% of breast cancer occurrences and have been correlated with increased tumor aggressiveness and invasiveness. The nuclear factor-κB (NF-κB) is overexpressed in a subset of HER2-positive breast cancers and its upregulation has been associated with the metastatic potential of HER2-overexpressing tumors. The present study aimed at determining the potential of plumbagin, a naturally occurring naphthoquinone, to inhibit the invasion of HER2-overexpressing breast cancer cells and determine the involvement of NF-κB inhibition in plumbagin-mediated cell invasion suppression. In the present research we showed that plumbagin inhibited the transcriptional activity of NF-κB in HER2-positive breast cancer cells. The suppression of NF-κB activation corresponded with the inhibition of NF-κB p65 phosphorylation and downregulation of NF-κB-regulated matrix metalloproteinase 9 (MMP-9) expression. Plumbagin suppressed the invasion of HER2-overexpressing breast cancer cells and the inhibition of cell invasion was associated with the ability of plumbagin to inhibit NF-κB transcriptional activity. The silencing of NF-κB p65 increased the sensitivity of HER2-overexpressing breast cancer cells to plumbagin-induced cell invasion inhibition. NF-κB inhibition was associated with IκB kinase α (IKKα) activity suppression and inhibition of IκBα phosphorylation and degradation. The knockdown of IKKα resulted in increased sensitivity of HER2-positive cells to plumbagin-induced suppression of NF-κB transcriptional activity and expression of MMP-9. In conclusion, plumbagin inhibits the invasion of HER2-overexpressing breast cancer cells through the inhibition of IKKα-mediated NF-κB activation and downregulation of NF-κB-regulated MMP-9 expression.

IGFBP2 Activates the NF-κB Pathway to Drive Epithelial-Mesenchymal Transition and Invasive Character in Pancreatic Ductal Adenocarcinoma

The molecular basis underlying the particularly aggressive nature of pancreatic ductal adenocarcinoma (PDAC) still remains unclear. Here we report evidence that the insulin-like growth factor-binding protein IGFBP2 acts as a potent oncogene to drive its extremely malignant character. We found that elevated IGFBP2 expression in primary tumors was associated with lymph node metastasis and shorter survival in patients with PDAC. Enforced expression of IGFBP2 promoted invasion and metastasis of PDAC cells in vitro and in vivo by inducing NF-κB-dependent epithelial-mesenchymal transition (EMT). Mechanistic investigations revealed that IGFBP2 induced the nuclear translocation and phosphorylation of the p65 NF-κB subunit through the PI3K/Akt/IKKβ pathway. Conversely, enforced expression of PTEN blunted this signaling pathway and restored an epithelial phenotype to PDAC cells in the presence of overexpressed IGFBP2. Overall, our results identify IGFBP2 as a pivotal regulator of an EMT axis in PDAC, the activation of which is sufficient to confer the characteristically aggressive clinical features of this disease. Cancer Res; 76(22); 6543-54. ©2016 AACR.

The Anti-Cancer Effect of Polyphenols against Breast Cancer and Cancer Stem Cells: Molecular Mechanisms

The high incidence of breast cancer in developed and developing countries, and its correlation to cancer-related deaths, has prompted concerned scientists to discover novel alternatives to deal with this challenge. In this review, we will provide a brief overview of polyphenol structures and classifications, as well as on the carcinogenic process. The biology of breast cancer cells will also be discussed. The molecular mechanisms involved in the anti-cancer activities of numerous polyphenols, against a wide range of breast cancer cells, in vitro and in vivo, will be explained in detail. The interplay between autophagy and apoptosis in the anti-cancer activity of polyphenols will also be highlighted. In addition, the potential of polyphenols to target cancer stem cells (CSCs) via various mechanisms will be explained. Recently, the use of natural products as chemotherapeutics and chemopreventive drugs to overcome the side effects and resistance that arise from using chemical-based agents has garnered the attention of the scientific community. Polyphenol research is considered a promising field in the treatment and prevention of breast cancer.

Lactate dehydrogenase inhibitors can reverse inflammation induced changes in colon cancer cells

The inflammatory microenvironment is an essential component of neoplastic lesions and can significantly impact on tumor progression. Besides facilitating invasive growth, inflammatory cytokines were also found to reprogram cancer cell metabolism and to induce aerobic glycolysis. Previous studies did not consider the possible contribution played in these changes by lactate dehydrogenase (LDH). The A isoform of LDH (LDH-A) is the master regulator of aerobic glycolysis; it actively reduces pyruvate and causes enhanced lactate levels in tumor tissues. In cancer cells, lactate was recently found to directly increase migration ability; moreover, when released in the microenvironment, it can facilitate matrix remodeling. In this paper, we illustrate that treatment of human colon adenocarcinoma cells with TNF-α and IL-17, two pro-inflammatory cytokines, modifies LDH activity, causing a shift toward the A isoform which results in increased lactate production. At the same time, the two cytokines appeared to induce features of epithelial-mesenchymal transition in the treated cells, such as reduction of E-cadherin levels and increased secretion of metalloproteinases. Noteworthy, oxamate and galloflavin, two inhibitors of LDH activity which reduce lactate production in cells, were found to relieve the inflammation-induced effects. These results suggest LDH-A and/or lactate as common elements at the cross-road between cancer cell metabolism, tumor progression and inflammation. At present, LDH inhibitors suitable for clinical use are actively searched as possible anti-proliferative agents; our data lead to hypothesize for these compounds a wider potential in anticancer treatment.

Endogenously synthesized n-3 fatty acids in fat-1 transgenic mice prevent melanoma progression by increasing E-cadherin expression and inhibiting β-catenin signaling

Malignant melanoma is the most lethal form of skin cancer. Although preclinical studies have shown that n-3 polyunsaturated fatty acids (PUFAs) are beneficial for prevention of melanoma, the molecular mechanisms underlying the protective effects of n‑3 PUFAs on melanoma remain largely unknown. In the present study, endogenously increased levels of n-3 PUFAs in the tumor tissues of omega‑3 fatty acid desaturase (fat‑1) transgenic mice was associated with a reduction in the growth rate of melanoma xenografts. This reduction in tumor growth in fat‑1 mice compared with wild‑type controls may have been associated, in part, to the: i) Increased expression of E‑cadherin and the reduced expression of its transcriptional repressors, the zinc finger E‑box binding homeobox 1 and snail family transcriptional repressor 1; ii) significant repression of the epidermal growth factor receptor/Akt/β‑catenin signaling pathway; and iii) formation of significant levels of n‑3 PUFA‑derived lipid mediators, particularly resolvin D2 and E1, maresin 1 and 15‑hydroxyeicosapentaenoic acid. In addition, vitamin E administration counteracted n‑3 PUFA‑induced lipid peroxidation and enhanced the antitumor effect of n‑3 PUFAs, which suggests that the protective role of n‑3 PUFAs against melanoma is not mediated by n‑3 PUFAs‑induced lipid peroxidation. These results highlight a potential role of n‑3 PUFAs supplementation for the chemoprevention of melanoma in high‑risk individuals, and as a putative adjuvant agent in the treatment of malignant melanoma.

Inactivation of M2 AChR/NF-κB signaling axis reverses epithelial-mesenchymal transition (EMT) and suppresses migration and invasion in non-small cell lung cancer (NSCLC)

Non-neuronal cholinergic system is involved in lung physiology and lung cancer. However, the biochemical events downstream acetylcholine (ACh) receptor activation leading to carcinogenesis and tumor progression are not fully understood. Our previous work has shown that non-neuronal ACh acts as an autoparacrine growth factor to stimulate cell proliferation and promote epithelial-mesenchymal transition (EMT) in non-small cell lung cancer (NSCLC) via activation of M2 muscarinic receptor (M2R). The aim of the present study was to delineate the underlying mechanisms linking M2R and lung tumor progression, which may provide potential therapeutic targets to delay lung cancer progression. Inhibition of M2R by antagonist or siRNA suppresses NSCLC cell migratory and invasive capacities, reverses EMT and simultaneously inactivates PI3K/Akt, MAPK ERK and NF-κB p65. On the other hand, M2R activation stimulates NSCLC migration and invasion and promotes EMT via NF-κB p65 activation. Moreover, NF-κB p65 activation induced by M2R activation was partially inhibited by either Akt or ERK inhibitor. Taken together, these results demonstrated for the first time that NF-κB p65 activation is essential in NSCLC progression associated with non-neuronal cholinergic system. Our data suggest that M2R/ERK/Akt/NF-κB axis could be a potential target for NSCLC treatment.

CCL21/CCR7 Axis Contributed to CD133+ Pancreatic Cancer Stem-Like Cell Metastasis via EMT and Erk/NF-κB Pathway

Background

Tumor metastasis is driven by malignant cells and stromal cell components of the tumor microenvironment. Cancer stem cells (CSCs) are thought to be responsible for metastasis by altering the tumor microenvironment. Epithelial-mesenchymal transition (EMT) processes contribute to specific stages of the metastatic cascade, promoted by cytokines and chemokines secreted by stromal cell components in the tumor microenvironment. C-C chemokine receptor 7 (CCR7) interacts with its ligand, chemokine ligand 21(CCL21), to mediate metastasis in some cancer cells lines. This study investigated the role of CCL21/CCR7 in promoting EMT and metastasis of cluster of differentiation 133⁺ (CD133⁺) pancreatic cancer stem-like cells.

Methods

Panc-1, AsPC-1, and MIA PaCa-2 pancreatic cancer cells were selected because of their aggressive invasive potentials. CCR7 expression levels were examined in total, CD133⁺ and CD133⁻ cell fractions by Immunofluorescence analysis and real time-quantitative polymerase chain reaction (RT-qPCR). The role of CCL21/CCR7 in mediating metastasis and survival of CD133⁺ pancreatic cancer stem-like cells was detected by Transwell assays and flow cytometry, respectively. EMT and lymph node metastasis related markers (E-cadherin, N- cadherin, LYVE-1) were analyzed by western blot. CCR7 expression levels were analyzed by immunohistochemical staining and RT-qPCR in resected tumor tissues, metastatic lymph nodes, normal lymph nodes and adjacent normal tissues from patients with pancreatic carcinoma.

Results

CCR7 expression was significantly increased in CD133⁺ pancreatic cancer stem-like cells, resected pancreatic cancer tissues, and metastatic lymph nodes, compared with CD133⁻ cancer cells, adjacent normal tissues and normal lymph nodes, respectively. CCL21/CCR7 promoted metastasis and survival of CD133⁺ pancreatic cancer stem-like cells and regulated CD133⁺ pancreatic cancer stem-like cells metastasis by modulating EMT and Erk/NF-κB pathway.

Conclusions

These results indicate a specific role for CCL21/CCR7 in promoting EMT and metastasis in CD133⁺ pancreatic cancer stem-like cells. Furthermore the data also indicated the potential importance of developing therapeutic strategies targeting cancer stem-like cells and CCL21/CCR7 for reducing metastasis.

Biopathological Significance of TLR9 Expression in Cancer Cells and Tumor Microenvironment Across Invasive Breast Carcinomas Subtypes

Toll-like receptors (TLRs) are pattern recognition receptors mainly expressed by cells of the immune system but also by epithelial tumor cells. Little is known about expression patterns of TLR genes in breast tumors, and their clinical significance is unclear. The aim of our study was to investigate expression of TLRs pathway components in pre-invasive breast lesions and invasive breast carcinomas (IBCs). We used RT-PCR assays to quantify mRNA levels of the 10 TLR genes and genes involved in TLR pathways in 350 breast tumors from patients with known clinical/pathological status and long-term outcome. Sets of 158 breast samples were also analyzed by immunochemistry including; 40 early noninvasive breast lesions, 38 IBCs and 80 triple negative carcinomas subtype (TNCs). We identified TLR9 as the major TLR gene family member upregulated in breast tumors and more particularly in TNCs. Immunohistochemical studies demonstrated that TLR9 protein was expressed in tumor epithelial and stromal cells of the TLR9 mRNA-overexpressing tumors. TLR9 overexpression appears very early during breast carcinogenesis. High TLR9 levels were associated with favorable outcome in the TNC sub-group. TLR9 overexpression was associated with alterations of down-stream components of the TLR9 signaling pathway, epithelio-mesenchymal transition (EMT) induction and EGFR pathway deregulation. TNCs with TLR9 overexpression were significantly correlated with development of a fibrous and inflammatory microenvironment with variable status of nuclear phosphoSTAT3. Our results suggest that TLR9 could play a role in TNC carcinogenesis and could be useful as predictive biomarker and therapeutic target.

IKK inhibitor suppresses epithelial-mesenchymal transition and induces cell death in prostate cancer

IκB kinase (IKK)/nuclear factor κB (NF-κB) pathway activation is a key event in the acquisition of invasive and metastatic capacities in prostate cancer. A potent small-molecule compound, BMS-345541, was identified as a highly selective IKKα and IKKβ inhibitor to inhibit kinase activity. This study explored the effect of IKK inhibitor on epithelial-mesenchymal transition (EMT), apoptosis and metastasis in prostate cancer. Here, we demonstrate the role of IKK inhibitor reducing proliferation and inducing apoptosis in PC-3 cells. Furthermore, BMS345541 inhibited IκBα phosphorylation and nuclear level of NF-κB/p65 in PC-3 cells. We also observed downregulation of the N-cadherin, Snail, Slug and Twist protein in a dose-dependent manner. BMS‑345541 induced upregulation of the epithelial marker E-cadherin and phosphorylated NDRG1 at protein level. Moreover, BMS‑345541 reduced invasion and metastasis of PC-3 cells in vitro. In conclusion, IKK has a key role in both EMT and apoptosis of prostate cancer. IKK inhibitor can reverse EMT and induce cell death in PCa cells. IKK was identified as a potential target structure for future therapeutic intervention in PCa.

Inflammatory bowel disease, colorectal cancer and type 2 diabetes mellitus: The links

The co-occurrence of the three disease entities, inflammatory bowel disease (IBD), colorectal cancer (CRC), type 2diabetes mellitus (T2DM) along with inflammation and dismicrobism has been frequently reported. Some authors have even suggested that dysbiosis could be the link through a molecular crosstalk of multiple inflammatory loops including TGFβ, NFKB, TNFα and ROS among others. This review focuses on the inflammatory process along with the role of microbiota in the pathophysiology of the three diseases. The etiology of IBD is multifactorial, and like CRC and T2DM, it is associated with a widespread and sustained GI inflammation and dismicrobism, whereby an array of pro-inflammatory mediators and other related biomolecules are up-regulated, both locally and systematically. Such a persistent or an inadequately resolved chronic inflammation may be a causative agent, in the presence other factors, leading to several pathologies such as IBD, CRC and T2DM. TGFβ plays a crucial role in pancreatic β cell malfunctioning as glucotoxicity stimulates its signaling cascade through smad 3, IL-6 and epithelial to mesenchymal transition. Such a cascade could lead to macrophages and other cells recruitment, inflammation, then IBD and CRC. NFkB is also another key regulator in the crosstalk among the pathways leading to the three disease entities. It plays a major role in linking inflammation to cancer development through its ability to up regulate several inflammatory and tumor promoting cytokines like: IL-6, IL-1 α and TNF α, as well as genes like BCL2 and BCLXL. It activates JAK/STAT signaling network via STAT3 transcription factors and promotes epithelial to mesenchymal transition. It also increases the risk for T2DM in obese people. In brief, NFKB is a matchmaker between inflammation, IBD, cancer and diabetes. In addition, TNFα plays a pivotal role in systemic inflammation. It is increased in the mucosa of IBD patients and has a central role in its pathogenesis. It also activates other signaling pathways like NFKB and MAPK leading to CRC. It is also overexpressed in the adipose tissues of obese patients thus linking it to T2DM, chronic inflammation and consequently CRC. On the other hand, increasing evidence suggests that dysbiosis plays a role in initiating, maintaining and determining the severity of IBD. Actually, among its functions, it modulates genotoxic metabolites which are able to induce CRC, a fact proven to be sustained by stool transfer from patients with CRC. Probiotics, however, may actively prevent CRC as well as IBD and results in a significant decrease in fasting glycemia in T2DM patients. In conclusion, IBD, CRC and T2DM are commonly occurring interrelated clinical problems. They share a common basis influenced by an inflammatory process, an imbalance in intestinal microbiota, and a crosstalk between various signaling pathways. Would probiotics interrupt the crosstalk or orient it in the physiological direction?

Dynamic self-guiding analysis of Alzheimer's disease

We applied a self-guiding evolutionary algorithm to initiate the synthesis of the Alzheimer's disease-related data and literature. A protein interaction network associated with amyloid-beta precursor protein (APP) and a seed model that treats Alzheimer's disease as progressive dysregulation of APP-associated signaling were used as dynamic “guides” and structural “filters” in the recursive search, analysis, and assimilation of data to drive the evolution of the seed model in size, detail, and complexity. Analysis of data and literature across sub-disciplines and system-scale discovery platforms suggests a key role of dynamic cytoskeletal connectivity in the stability, plasticity, and performance of multicellular networks and architectures. Chronic impairment and/or dysregulation of cell adhesions/synapses, cytoskeletal networks, and/or reversible epithelial-to-mesenchymal-like transitions, which enable and mediate the stable and coherent yet dynamic and reconfigurable multicellular architectures, may lead to the emergence and persistence of the disordered, wound-like pockets/microenvironments of chronically disconnected cells. Such wound-like microenvironments support and are supported by pro-inflammatory, pro-secretion, de-differentiated cellular phenotypes with altered metabolism and signaling. The co-evolution of wound-like microenvironments and their inhabitants may lead to the selection and stabilization of degenerated cellular phenotypes, via acquisition of epigenetic modifications and mutations, which eventually result in degenerative disorders such as cancer and Alzheimer's disease.

Hypoxia inducible factor-1α-dependent epithelial to mesenchymal transition under hypoxic conditions in prostate cancer cells

Prostate cancer is the most commonly diagnosed cancer in men and the second leading cause of cancer death. Hypoxia is an environmental stimulus that plays an important role in the development and cancer progression especially for solid tumors. The key regulator under hypoxic conditions is stabilized hypoxia-inducible factor (HIF)-1α. In the present study, immune-fluorescent staining, siRNAs, qRT-PC, immunoblotting, cell migration and invasion assays were carried out to test typical epithelial to mesenchymal transition under hypoxia and the key regulators of this process in PC3, a human prostate cancer cell line. Our data demonstrated that hypoxia induces diverse molecular, phenotypic and functional changes in prostate cancer cells that are consistent with EMT. We also showed that a cell signal factor such as HIF-1α, which might be stabilized under hypoxic environment, is involved in EMT and cancer cell invasive potency. The induced hypoxia could be blocked by HIF-1α gene silencing and reoxygenation of EMT in prostate cancer cells, hypoxia partially reversed accompanied by a process of mesenchymal-epithelial reverting transition (MErT). EMT might be induced by activation of HIF-1α-dependent cell signaling in hypoxic prostate cancer cells.

Activation of G-Protein-Coupled Estrogen Receptor Inhibits the Migration of Human Nonsmall Cell Lung Cancer Cells via IKK-β/NF-κB Signals

Estrogen signals have been suggested to modulate the progression and metastasis of nonsmall cell lung cancer (NSCLC), which is one of the leading causes of cancer deaths worldwide. While there are limited data concerning the roles and effects of G-protein-coupled estrogen receptor (GPER) on the progression of NSCLC, our present study reveals that the expression of GPER in NSCLC cells is obviously greater than that in lung fibroblast cell line MRC-5. Activation of GPER via its specific agonist G-1 decreases the in vitro motility of A549 and H358 cells and the expression of matrix metalloproteinase 2 (MMP-2) and MMP-9. Further, G-1 treatment can rapidly decrease the phosphorylation, nuclear translocation, and promoter activities of NF-κB in NSCLC cells. BAY 11-7082, the inhibitor of NF-κB, also inhibits the expression of MMP-2/9, while overexpression of p65 significantly attenuates G-1-induced downregulation of MMP-2/9. It suggests that inhibition of NF-κB mediates G-1-induced MMP-2/9 downregulation. G-1 treatment significantly down regulates the phosphorylation of IκB kinase β (IKK-β) and IκBα, while not IKK-α, in both 549 and H358 cells. ACHP, the specific inhibitor of IKK-β, can reinforce G-1-induced MMP-2/9 downregulation and invasion suppression of A549 cells. Collectively, our results suggest that activation of GPER can inhibit the migration of human NSCLC cells via suppression of IKK-β/NF-κB signals. These findings will help to better understand the roles and mechanisms of GPER as a potential therapy target for NSCLC patients.

Deferoxamine-induced increase in the intracellular iron levels in highly aggressive breast cancer cells leads to increased cell migration by enhancing TNF-α-dependent NF-κB signaling and TGF-β signaling

Recent studies have suggested that excess iron accumulation may be a risk factor for breast cancer. However the role of iron in breast cancer metastasis has remained unclear. The major goal of our study is to investigate the roles of iron in breast cancer metastasis. We modulated the intracellular iron levels of human breast cancer cells, including the aggressive MDA-MB-231 cells and non-aggressive MCF-7 cells, by using Deferoxamine (DFO) - a most widely used iron chelator. We found that DFO treatment could deplete intracellular iron in MCF-7 cells. In contrast, DFO treatment led to a significant increase in the intracellular iron level in MDA-MB-231 cells. The MDA-MB-231 cells with the increased intracellular iron level exhibited increases in both mesenchymal markers and cell migration. Furthermore, the DFO-treated MDA-MB-231 cells showed increases in both tumor necrosis factor α (TNF-α)-induced nuclear factor kappa B (NF-κB) signaling and transforming growth factor-β (TGF-β) signaling, which could contribute to the enhanced cell migration. Collectively, our study has provided the first evidence suggesting that increased intracellular iron levels could lead to enhanced migration of aggressive breast cancer cells by increasing TNF-α-dependent NF-κB signaling and TGF-β signaling. Our study has also suggested that caution should be taken when DFO is applied for treating breast cancer cells, since DFO could produce differential effects on the intracellular iron levels for aggressive breast cancer cells and non-aggressive breast cancer cells.

Viral Carcinogenesis Beyond Malignant Transformation: EBV in the Progression of Human Cancers

Cancer progression begins when malignant cells colonize adjacent sites, and it is characterized by increasing tumor heterogeneity, invasion and dissemination of cancer cells. Clinically, progression is the most relevant stage in the natural history of cancers. A given virus is usually regarded as oncogenic because of its ability to induce malignant transformation of cells. Nonetheless, oncogenic viruses may also be important for the progression of infection-associated cancers. Recently this hypothesis has been addressed because of studies on the contribution of the Epstein-Barr virus (EBV) to the aggressiveness of nasopharyngeal carcinoma (NPC). Several EBV products modulate cancer progression phenomena, such as the epithelial-mesenchymal transition, cell motility, invasiveness, angiogenesis, and metastasis. In this regard, there are compelling data about the effects of EBV latent membrane proteins (LMPs) and EBV nuclear antigens (EBNAs), as well as nontranslated viral RNAs, such as the EBV-encoded small nonpolyadenylated RNAs (EBERs) and viral microRNAs, notably EBV miR-BARTs. The available data on the mechanisms and players involved in the contribution of EBV infection to the aggressiveness of NPC are discussed in this review. Overall, this conceptual framework may be valuable for the understanding of the contribution of some infectious agents in the progression of cancers.

The NF-κB Pathway and Cancer Stem Cells

The NF-κB transcription factor pathway is a crucial regulator of inflammation and immune responses. Additionally, aberrant NF-κB signaling has been identified in many types of cancer. Downstream of key oncogenic pathways, such as RAS, BCR-ABL, and Her2, NF-κB regulates transcription of target genes that promote cell survival and proliferation, inhibit apoptosis, and mediate invasion and metastasis. The cancer stem cell model posits that a subset of tumor cells (cancer stem cells) drive tumor initiation, exhibit resistance to treatment, and promote recurrence and metastasis. This review examines the evidence for a role for NF-κB signaling in cancer stem cell biology.

Osteopontin-A Master Regulator of Epithelial-Mesenchymal Transition

Osteopontin (OPN) plays an important functional role in both physiologic and pathologic states. OPN is implicated in the progression of fibrosis, cancer, and metastatic disease in several organ systems. The epithelial-mesenchymal transition (EMT), first described in embryology, is increasingly being recognized as a significant contributor to fibrotic phenotypes and tumor progression. Several well-established transcription factors regulate EMT and are conserved across tissue types and organ systems, including TWIST, zinc finger E-box-binding homeobox (ZEB), and SNAIL-family members. Recent literature points to an important relationship between OPN and EMT, implicating OPN as a key regulatory component of EMT programs. In this review, OPN’s interplay with traditional EMT activators, both directly and indirectly, will be discussed. Also, OPN’s ability to restructure the tissue and tumor microenvironment to indirectly modify EMT will be reviewed. Together, these diverse pathways demonstrate that OPN is able to modulate EMT and provide new targets for directing therapeutics.

N-Myc-interacting protein (NMI) negatively regulates epithelial-mesenchymal transition by inhibiting the acetylation of NF-κB/p65

The epithelial-mesenchymal transition (EMT) plays an essential role in embryonic development, wound healing, tissue regeneration, organ fibrosis, and tumor progression. However, the mechanisms underlying this process are poorly understood. Many signaling pathways, including the NF-κB signaling pathway, trigger EMT during development and differentiation. In the present study, we report that N-Myc interactor (NMI) inhibits EMT progression by suppressing transcriptional activities of NF-κB in human gastric cancer cells. We show that the expression of NMI is significantly reduced in invasive gastric cancer cells and gastric cancer tissues. Overexpression of NMI inhibited cell migration and invasion, and this inhibition was enhanced after TNF-α stimulation. Tumorigenicity assay in nude mice support the notion that NMI inhibits EMT in cancer cells. Mechanistically, NMI promotes the interaction between NF-κB/p65 and histone deacetylases (HDACs) and inhibits the acetylation and transcriptional activity of p65. The expression of p65 rescues NMI-mediated inhibition of EMT and the inhibition of the acetylation of p65 mediated by NMI is HDACs-dependent. Taken together, these findings suggest that NMI can suppress tumor invasion and metastasis by inhibiting NF-κB pathways, providing an alternative mechanism for EMT inhibition in stomach neoplasm.

Overexpression of Livin promotes migration and invasion of colorectal cancer cells by induction of epithelial-mesenchymal transition via NF-κB activation

Livin is a novel member of the inhibitors of apoptosis protein family and has been implicated in the development and progression of colorectal cancer (CRC). However, the underlying mechanisms of Livin in CRC remain not fully understood. In this study, we investigated the effects of Livin expression on the proliferation and metastasis of CRC cells and also addressed its related molecular mechanism to metastasis. The expression of Livin in CRC cells (HCT116, SW480, and HT-29 cell lines) was determined by Western blot analysis. Our results show that the overexpression of Livin significantly promotes the proliferation, migration, and invasion of SW480 cells. Concurrently, the inhibition of Livin reduces the proliferation, migration, and invasion of HCT116 cells. In addition, Livin overexpression promotes the epithelial–mesenchymal transition, as evidenced by a decrease in epithelial E-cadherin expression and an increase in mesenchymal markers, including vimentin, Slug, and Snail. Furthermore, adding the NF-κB inhibitor, BAY 11-7028, or transfecting with small interfering RNA against p65 notably restores the expression level of E-cadherin and attenuates the invasive ability of Livin-overexpressing cells. Taken together, these results indicate that Livin potentiates migration and invasion of CRC cells partially through the induction of epithelial–mesenchymal transition via NF-κB activation. Livin may be a potential therapeutic target for CRC.

The bounty of nature for changing the cancer landscape

The landscape of cancer has changed considerably in past several years, due mainly to aggressive screening, accumulation of data from basic and epidemiological studies, and the advances in translational research. Natural anticancer agents have always been a part and parcel of cancer research. The initial focus on natural anticancer agents was in context of their cancer chemopreventive properties but their ability to selectively target oncogenic signaling pathways has also been recognized. In light of the rapid advancements in our understanding of the role of microRNAs, cancer stem cells, and epigenetic events in cancer initiation and progression, a number of natural anticancer agents are showing promise in vitro, in vivo as well as in preclinical studies. Moreover, parent structures of natural agents are being extensively modified with the hope of improving efficacy, specificity, and bioavailability. In this article, we focus on two natural agents, 3,3'-diindolylmethane and garcinol, along with 3,4-difluorobenzo curcumin, a synthetic analog of natural agent curcumin. We showcase how these anticancer agents are changing cancer landscape by modulating novel microRNAs, epigenetic factors, and cancer stem cell markers. These activities are relevant and being appreciated for overcoming drug resistance and inhibition of metastases, the two overarching clinical challenges in modern medicine.

Development of Functional Microfold (M) Cells from Intestinal Stem Cells in Primary Human Enteroids

Background & Aims

Intestinal microfold (M) cells are specialized epithelial cells that act as gatekeepers of luminal antigens in the intestinal tract. They play a critical role in the intestinal mucosal immune response through transport of viruses, bacteria and other particles and antigens across the epithelium to immune cells within Peyer’s patch regions and other mucosal sites. Recent studies in mice have demonstrated that M cells are generated from Lgr5+ intestinal stem cells (ISCs), and that infection with Salmonella enterica serovar Typhimurium increases M cell formation. However, it is not known whether and how these findings apply to primary human small intestinal epithelium propagated in an in vitro setting.

Methods

Human intestinal crypts were grown as monolayers with growth factors and treated with recombinant RANKL, and assessed for mRNA transcripts, immunofluorescence and uptake of microparticles and S. Typhimurium.

Results

Functional M cells were generated by short-term culture of freshly isolated human intestinal crypts in a dose- and time-dependent fashion. RANKL stimulation of the monolayer cultures caused dramatic induction of the M cell-specific markers, SPIB, and Glycoprotein-2 (GP2) in a process primed by canonical WNT signaling. Confocal microscopy demonstrated a pseudopod phenotype of GP2-positive M cells that preferentially take up microparticles. Furthermore, infection of the M cell-enriched cultures with the M cell-tropic enteric pathogen, S. Typhimurium, led to preferential association of the bacteria with M cells, particularly at lower inoculum sizes. Larger inocula caused rapid induction of M cells.

Conclusions

Human intestinal crypts containing ISCs can be cultured and differentiate into an epithelial layer with functional M cells with characteristic morphological and functional properties. This study is the first to demonstrate that M cells can be induced to form from primary human intestinal epithelium, and that S. Typhimurium preferentially infect these cells in an in vitro setting. We anticipate that this model can be used to generate large numbers of M cells for further functional studies of these key cells of intestinal immune induction and their impact on controlling enteric pathogens and the intestinal microbiome.

Folate Deficiency Triggered Apoptosis of Synoviocytes: Role of Overproduction of Reactive Oxygen Species Generated via NADPH Oxidase/Mitochondrial Complex II and Calcium Perturbation

Despite a plethora of literature has documented that osteoarthritis (OA) is veritably associated with oxidative stress-mediated chondrocyte death and matrix degradation, yet the possible involvement of synoviocyte abnormality as causative factor of OA has not been thoroughly investigated. For this reason, we conduct the current studies to insight into how synoviocytes could respond to an episode of folate-deprived (FD) condition. First, when HIG-82 synoviocytes were cultivated under FD condition, a time-dependent growth impediment was observed and the demise of these cells was demonstrated to be apoptotic in nature mediated through FD-evoked overproduction of reactive oxygen species (ROS) and drastically released of cytosolic calcium (Ca²⁺) concentrations. Next, we uncovered that FD-evoked ROS overproduction could only be strongly suppressed by either mitochondrial complex II inhibitors (TTFA and carboxin) or NADPH oxidase (NOX) inhibitors (AEBSF and apocynin), but not by mitochondrial complex I inhibitor (rotenone) and mitochondrial complex III inhibitor (antimycin A). Interestingly, this selective inhibition of FD-evoked ROS by mitochondrial complex II and NOX inhibitors was found to correlate excellently with the suppression of cytosolic Ca²⁺ release and reduced the magnitude of the apoptotic TUNEL-positive cells. Taken together, we present the first evidence here that FD-triggered ROS overproduction in synoviocytes is originated from mitochondrial complex II and NOX. Both elevated ROS in tandem with cytosolic Ca²⁺ overload serve as final arbitrators for apoptotic lethality of synoviocytes cultivated under FD condition. Thus, folate supplementation may be beneficial to patients with OA.

Expression of pigment epithelium-derived factor is associated with a good prognosis and is correlated with epithelial-mesenchymal transition-related genes in infiltrating ductal breast carcinoma

Epithelial-mesenchymal transition (EMT) is a pivotal event in the progression of cancer towards metastasis. Given that pigment epithelium-derived factor (PEDF) inhibits angiogenesis, the present study analyzed whether PEDF expression is associated with EMT and prognosis in invasive ductal breast cancer (IDC). Immunohistochemical analysis was used to examine the expression levels of PEDF, E-cadherin, vimentin, Snail and nuclear factor-κB (NF-κB) in 119 cases of IDC. Correlations between PEDF expression and EMT-related genes, and clinicopathological features and clinical prognosis were analyzed. E-cadherin, vimentin, Snail and NF-κB expression was correlated with tumor size, lymph node metastasis and clinicopathological stage. PEDF expression was closely associated with tumor size. Spearman's rank correlation analysis revealed a positive correlation between PEDF and E-cadherin, vimentin, Snail and NF-κB expression (P<0.05). Additionally, Kaplan-Meier survival analysis demonstrated that the five-year survival rate was higher for patients with PEDF- and E-cadherin-positive tumors, but was lower for those with vimentin-, Snail- and NF-κB-positive tumors. Vimentin, E-cadherin and NF-κB levels were dependent prognostic factors of favorable outcomes in IDC, as determined by Cox multivariate analysis. PEDF expression in breast cancer was significantly associated with EMT-related genes, suggesting that it may be an EMT suppressor. However, its potential as a prognostic indicator in breast cancer warrants further investigation.

URGCP promotes non-small cell lung cancer invasiveness by activating the NF-κB-MMP-9 pathway

Invasion and metastasis are main traits of tumor progression and responsible for the poor prognosis of advanced non-small cell lung cancer (NSCLC). The molecular mechanisms underlying the malignant behaviors of NSCLC remain incompletely understood. The present study demonstrate that up-regulator of cell proliferation (URGCP), a recently identified tumor-promoting gene found in several tumor types, is markedly overexpressed in human NSCLC cell lines and clinical NSCLC samples. URGCP upregulation correlates significantly with the progression and poor prognosis of this disease. In vitro and in vivo studies demonstrate that increasing URGCP expression accelerates invasion, migration, and distant metastasis of NSCLC cells whereas downregulating URGCP suppresses these malignant traits. Notably, silencing URGCP expression almost completely abrogates the metastatic ability of NSCLC cells. At the molecular level, URGCP markedly promotes MMP-9 expression by activating NF-κB signaling. Additionally, URGCP and MMP-9 expression are positively correlated in various cohorts of human NSCLC specimens, and NF-κB-activated MMP-9 expression contributes to URGCP-induced invasiveness of NSCLC cell lines. Collectively, these findings indicate that URGCP plays an important role in promoting NSCLC cell invasion and metastasis by enhancing NF-κB-activated MMP-9 expression and may serve as a potential therapeutic target and prognostic marker.

Shikonin as an inhibitor of the LPS-induced epithelial-to-mesenchymal transition in human breast cancer cells

Shikonin (SK), a natural naphthoquinone isolated from the Chinese medicinal herb, has been known to suppress the proliferation of several cancer cells. However, its role in the epithelial mesenchymal transition (EMT) has yet to be demonstrated. The aim of the present study was to examine the effects of SK on EMT. Lipopolysaccharide (LPS) induced EMT-like phenotypic changes, enhancing cell migration and invasion. SK markedly reduced the expression of the LPS-induced EMT markers, including N-cadherin in MDA-MB‑231 cells, and increased the expression of E-cadherin in MCF-7 cells. SK also inhibited cell migration and invasion in vitro. The effects of SK on the LPS-induced EMT were mediated by the inactivation of the NF-κB-Snail signaling pathway. The results provided new evidence that SK suppresses breast cancer cell invasion and migration by inhibiting the EMT. Therefore, SK is a potentially effective anticancer agent for breast tumors, by inhibiting metastasis.

Proteomic Characterization of Annexin l (ANX1) and Heat Shock Protein 27 (HSP27) as Biomarkers for Invasive Hepatocellular Carcinoma Cells

To search for reliable biomarkers and drug targets for management of hepatocellular carcinoma (HCC), we performed a global proteomic analysis of a pair of HCC cell lines with distinct differentiation statuses using 2-DE coupled with MALDI-TOF MS. In total, 106 and 55 proteins were successfully identified from the total cell lysate and the cytosolic, nuclear and membrane fractions in well-differentiated (HepG2) and poorly differentiated (SK-Hep–1) HCC clonal variants, respectively. Among these proteins, nine spots corresponding to proteins differentially expressed between HCC cell types were selected and confirmed by immunofluorescence staining and western blotting. Notably, Annexin 1 (ANX1), ANX–2, vimentin and stress-associated proteins, such as GRP78, HSP75, HSC–70, protein disulfide isomerase (PDI), and heat shock protein–27 (HSP27), were exclusively up-regulated in SK-Hep–1 cells. Elevated levels of ANX–4 and antioxidant/metabolic enzymes, such as MnSOD, peroxiredoxin, NADP-dependent isocitrate dehydrogenase, α-enolase and UDP-glucose dehydrogenase, were observed in HepG2 cells. We functionally demonstrated that ANX1 and HSP27 were abundantly overexpressed only in highly invasive types of HCC cells, such as Mahlavu and SK-Hep–1. Knockdown of ANX1 or HSP27 in HCC cells resulted in a severe reduction in cell migration. The in-vitro observations of ANX1 and HSP27 expressions in HCC sample was demonstrated by immunohistochemical stains performed on HCC tissue microarrays. Poorly differentiated HCC tended to have stronger ANX1 and HSP27 expressions than well-differentiated or moderately differentiated HCC. Collectively, our findings suggest that ANX1 and HSP27 are two novel biomarkers for predicting invasive HCC phenotypes and could serve as potential treatment targets.

The dual role of iNOS in cancer

Nitric oxide (NO) is one of the 10 smallest molecules found in nature. It is a simple gaseous free radical whose predominant functions is that of a messenger through cGMP. In mammals, NO is synthesized by the enzyme nitric oxide synthase (NOS) of which there are three isoforms. Neuronal (nNOS, NOS1) and endothelial (eNOS, NOS3) are constitutive calcium-dependent forms of the enzyme that regulate neural and vascular function respectively. The third isoform (iNOS, NOS2), is calcium-independent and is inducible. In many tumors, iNOS expression is high, however, the role of iNOS during tumor development is very complex and quite perplexing, with both promoting and inhibiting actions having been described. This review will aim to summarize the dual actions of iNOS-derived NO showing that the microenvironment of the tumor is a contributing factor to these observations and ultimately to cellular outcomes.

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NO is pro- and anti-tumorigenic. High concentrations of NO maybe anti-tumorigenic.

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iNOS produces high concentrations of NO and relates to tumor growth or its inhibition.

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iNOS is associated with cytotoxicity, apoptosis and bystander anti-tumor effects.

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Tumor- and stromal-iNOS, and the ‘cell situation’ contribute to anti or pro-tumor effects.

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Dual role of iNOS is influenced by the cell situation and is environment dependent.

p53 modulates NF-κB mediated epithelial-to-mesenchymal transition in head and neck squamous cell carcinoma

OBJECTIVES

To investigate the role of p53 in NF-κB mediated epithelial-to-mesenchymal (EMT) in head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

We utilized HNSCC and normal oral epithelial cell lines as our model system. We used a lentiviral shRNA system to silence the expression of p65 and p53 in these cell lines. Mutant and wild-type (WT) p53 background genotypes were analyzed. The expression of epithelial and mesenchymal markers was determined using western blotting and quantitative PCR assays. Cell morphology, growth, and invasion were determined using a 3-dimensional spheroid culture and anchorage independent growth (AIG) assays.

RESULTS

In HNSCC cells with mutant p53 we found that silencing p65 expression promoted EMT. In contrast, in the context of WT p53, ectopic p65 over-expression promoted EMT. Ablation of WT p53 in normal oral epithelial cells blocked EMT induced by p65 over-expression. We demonstrate that AIG and apoptosis induced by NF-κB activation is regulated by p53.

CONCLUSION

Our data demonstrates that p53 mutational status is critical in determining the outcome of NF-κB activation in HNSCC. In the presence of WT p53, excess p65 signal can promote EMT. Conversely, ablation of p65 in the context of mutant p53 drives EMT. These results demonstrate that p53 mutational status alters the outcome of NF-κB signaling. These results, though preliminary, demonstrate the critical role of p53 mutational status in determining the outcome of NF-κB signaling and suggest that monitoring p53 status may inform the utility of NF-κB inhibitor treatment in HNSCC.

Aqueous extract of Psoralea corylifolia L. inhibits lipopolysaccharide-induced endothelial-mesenchymal transition via downregulation of the NF-κB-SNAIL signaling pathway

The epithelial-mesenchymal transition (EMT) is a pivotal event in the invasion and metastasis of cancer cells. Psoralea corylifolia L. (PC) inhibits the proliferation of various cancer cells. However, its possible role in EMT has not been identified. In the present study, we examined the effects of an aqueous extract of Psoralea corylifolia L. (PCAE), a typical medicinal decoction, on the EMT. Lipopolysaccharide (LPS) induced EMT-like phenotypic changes, enhancing cell migration and invasion. However, PCAE markedly reduced the expression of the LPS-induced EMT markers, including N-cadherin and vimentin, and increased the expression of β-catenin. PCAE also inhibited cell migration and invasion in vitro. The effects of PCAE on the LPS-induced EMT were mediated by the inactivation of the NF-κB-SNAIL signaling pathway. The results provide new evidence that PCAE suppresses cancer cell invasion and migration by inhibiting EMT. Therefore, PCAE is a potentially effective dietary chemopreventive agent for malignant tumors since it inhibits metastasis.

Mammaglobin 1 promotes breast cancer malignancy and confers sensitivity to anticancer drugs

Mammaglobin 1 (MGB1), a member of the secretoglobin family, is expressed in mammary epithelial tissues and is overexpressed in most mammary carcinomas. Despite the extensive research correlating MGB1 expression profiles to breast cancer pathogenesis and disease outcome, the biological significance of MGB1 in cancer processes is still unclear. We have thus set out to conduct a functional evaluation of the molecular and cellular roles of MGB1 in breast cancer processes leading to disease progression. Using a series of breast cancer cell models with conditional MGB1 expression, we demonstrate that MGB1 promotes cancer cell malignant features. More specifically, loss of MGB1 expression resulted in a decrease of cell proliferation, soft agar spheroid formation, migration, and invasion capacities of breast cancer cells. Concomitantly, we also observed that MGB1 expression activates signaling pathways mediated by MAPK members (p38, JNK, and ERK), the focal adhesion kinase (FAK), matrix metalloproteinases (MMPs) and NFκB. Moreover, MGB1 regulates epithelial to mesenchymal (EMT) features and modulates Snail, Twist and ZEB1 expression levels. Interestingly, we also observed that expression of MGB1 confers breast cancer cell sensitivity to anticancer drug-induced apoptosis. Together, our results support a role for MGB1 in tumor malignancy in exchange for chemosensitivity. These findings provide one of the first descriptive overview of the molecular and cellular roles of MGB1 in breast cancer processes and may offer new insight to the development of therapeutic and prognostic strategies in breast cancer patients. © 2015 Wiley Periodicals, Inc.

BTB-Zinc Finger Oncogenes Are Required for Ras and Notch-Driven Tumorigenesis in Drosophila

During tumorigenesis, pathways that promote the epithelial-to-mesenchymal transition (EMT) can both facilitate metastasis and endow tumor cells with cancer stem cell properties. To gain a greater understanding of how these properties are interlinked in cancers we used Drosophila epithelial tumor models, which are driven by orthologues of human oncogenes (activated alleles of Ras and Notch) in cooperation with the loss of the cell polarity regulator, scribbled (scrib). Within these tumors, both invasive, mesenchymal-like cell morphology and continual tumor overgrowth, are dependent upon Jun N-terminal kinase (JNK) activity. To identify JNK-dependent changes within the tumors we used a comparative microarray analysis to define a JNK gene signature common to both Ras and Notch-driven tumors. Amongst the JNK-dependent changes was a significant enrichment for BTB-Zinc Finger (ZF) domain genes, including chronologically inappropriate morphogenesis (chinmo). chinmo was upregulated by JNK within the tumors, and overexpression of chinmo with either Ras^V12 or N^intra was sufficient to promote JNK-independent epithelial tumor formation in the eye/antennal disc, and, in cooperation with Ras^V12, promote tumor formation in the adult midgut epithelium. Chinmo primes cells for oncogene-mediated transformation through blocking differentiation in the eye disc, and promoting an escargot-expressing stem or enteroblast cell state in the adult midgut. BTB-ZF genes are also required for Ras and Notch-driven overgrowth of scrib mutant tissue, since, although loss of chinmo alone did not significantly impede tumor development, when loss of chinmo was combined with loss of a functionally related BTB-ZF gene, abrupt, tumor overgrowth was significantly reduced. abrupt is not a JNK-induced gene, however, Abrupt is present in JNK-positive tumor cells, consistent with a JNK-associated oncogenic role. As some mammalian BTB-ZF proteins are also highly oncogenic, our work suggests that EMT-promoting signals in human cancers could similarly utilize networks of these proteins to promote cancer stem cell states.

Extracellular vesicles from women with breast cancer promote an epithelial-mesenchymal transition-like process in mammary epithelial cells MCF10A

Extracellular vesicles (EVs) mediate many stages of tumor progression including angiogenesis, escape from immune surveillance, and extracellular matrix degradation. We studied whether EVs from plasma of women with breast cancer are able to induce an epithelial-mesenchymal transition (EMT) process in mammary epithelial cells MCF10A. Our findings demonstrate that EVs from plasma of breast cancer patients induce a downregulation of E-cadherin expression and an increase of vimentin and N-cadherin expression. Moreover, EVs induce migration and invasion, as well as an increase of NFκB-DNA binding activity and MMP-2 and MMP-9 secretions. In summary, our findings demonstrate, for the first time, that EVs from breast cancer patients induce an EMT-like process in human mammary non-tumorigenic epithelial cells MCF10A.

Key nodes of a microRNA network associated with the integrated mesenchymal subtype of high-grade serous ovarian cancer

Metastasis is the main cause of cancer mortality. One of the initiating events of cancer metastasis of epithelial tumors is epithelial-to-mesenchymal transition (EMT), during which cells dedifferentiate from a relatively rigid cell structure/morphology to a flexible and changeable structure/morphology often associated with mesenchymal cells. The presence of EMT in human epithelial tumors is reflected by the increased expression of genes and levels of proteins that are preferentially present in mesenchymal cells. The combined presence of these genes forms the basis of mesenchymal gene signatures, which are the foundation for classifying a mesenchymal subtype of tumors. Indeed, tumor classification schemes that use clustering analysis of large genomic characterizations, like The Cancer Genome Atlas (TCGA), have defined mesenchymal subtype in a number of cancer types, such as high-grade serous ovarian cancer and glioblastoma. However, recent analyses have shown that gene expression-based classifications of mesenchymal subtypes often do not associate with poor survival. This “paradox” can be ameliorated using integrated analysis that combines multiple data types. We recently found that integrating mRNA and microRNA (miRNA) data revealed an integrated mesenchymal subtype that is consistently associated with poor survival in multiple cohorts of patients with serous ovarian cancer. This network consists of 8 major miRNAs and 214 mRNAs. Among the 8 miRNAs, 4 are known to be regulators of EMT. This review provides a summary of these 8 miRNAs, which were associated with the integrated mesenchymal subtype of serous ovarian cancer.

Silencing of LRRFIP1 reverses the epithelial-mesenchymal transition via inhibition of the Wnt/β-catenin signaling pathway

The canonical Wnt/β-catenin signaling pathway has been shown to promote the epithelial-mesenchymal transition (EMT), which is a crucial process in multiple embryonic developmental processes and the progression of carcinomas. We recently provided evidence that leucine-rich repeat flightless-1-interacting protein 1 (LRRFIP1) promotes cancer metastasis and invasion. In the present study, we identified the signaling elements targeted by LRRFIP1 for promotion of the EMT in pancreatic and lung cancer. LRRFIP1 silencing reversed the EMT, as shown by increased expression of E-cadherin (an epithelial marker) and decreased expression of vimentin (a mesenchymal marker). Silencing of LRRFIP1 up-regulated phosphorylation of β-catenin and decreased its nuclear localization by targeting the β-catenin destruction complex. The expression of β-catenin and E-cadherin in the plasma membrane fraction was increased in LRRFIP1 silenced cancer cells, and the migration and invasion capabilities were strongly inhibited. In addition, this protein was highly expressed at the invasion front of malignant tissue collected from pancreatic cancer patients. Consequently, our data strongly suggested that LRRFIP1 played an important role in the invasion of carcinoma cells. Our data provide experimental evidence that LRRFIP1 is an attractive candidate for targeted therapy in human cancers.

De-SUMOylation of FOXC2 by SENP3 promotes the epithelial-mesenchymal transition in gastric cancer cells

The impact of cellular oxidative stress in promoting the epithelial-mesenchymal transition (EMT) has been noticed. Our previous study shows that SENP3, a redox-sensitive SUMO2/3-specific protease, accumulates in a variety of cancers, but whether SENP3 and SUMOylation involve in the regulation of EMT is unclear. The present study uncovers a novel role of SENP3 in promoting the EMT process in gastric cancer via regulating an EMT-inducing transcription factor, forkhead box C2 (FOXC2). We demonstrate that the expression of mesenchymal marker genes and cell migration ability are enhanced in SENP3-overexpressing gastric cancer cells and attenuated in SENP3-knockdown cells. A nude mouse model and a set of patient's specimens suggest the correlation between SENP3 and gastric cancer metastasis. Biochemical assays identify FOXC2 as a substrate of SENP3. Meanwhile N-cadherin is verified as a target gene of FOXC2, which is transcriptionally activated by a SUMO-less FOXC2. Additionally, reactive oxygen species-induced de-SUMOylation of FOXC2 can be blocked by silencing endogenous SENP3. In conclusion, SENP3, which is increased in gastric cancer cells, potentiates the transcriptional activity of FOXC2 through de-SUMOylation, in favor of the induction of specific mesenchymal gene expression in gastric cancer metastasis.

Antimetastatic effects of Celastrus orbiculatus on human gastric adenocarcinoma by inhibiting epithelial-mesenchymal transition and NF-κB/snail signaling pathway

AIM OF THE STUDY

Celastrus orbiculatus has been used as a folk medicine in China for the treatment of many diseases. In the laboratory, the ethyl acetate extract of Celastrus orbiculatus (COE) displays a wide range of anticancer functions. However, the inhibition of the metastasis mechanism of COE in gastric cancer cells has not been investigated so far. The present study was undertaken to determine if the antimetastatic effects of COE were involved in inhibition of the epithelial-mesenchymal transition (EMT) of human gastric adenocarcinoma SGC-7901 cells.

METHODS

The adhesion, invasion, and migration of SGC-7901 cells were determined by COE treatment in vitro, using Matrigel-coated plate, transwell membrane chamber, and wound healing models, respectively. In vivo, the growth-inhibiting and antimetastatic effects of COE on the nude mice model of gastric cancer were tested and the mechanisms were explored. The expression of EMT markers and nuclear factor κB (NF-κB)/Snail signaling pathway were evaluated by using western blotting and immunohistochemistry.

RESULTS

Treatment with COE dose-dependently inhibited the proliferation, adhesion, invasion, and migration of SGC-7901 cells in vitro, which was realized by enhancing the expression of E-cadherin and reducing N-cadherin and vimentin expression. Moreover, COE suppressed the activation of NF-κB/Snail signaling pathway induced by tumor necrosis factor-α. In addition, COE effectively suppressed tumor growth and metastasis in the nude mice model due to reduced expression of N-cadherin, vimentin, NF-κB p65, and Snail and increased expression of E-cadherin in the tumor tissues.

CONCLUSION

Our findings provided new evidence that COE is an effective inhibitor of metastatic potential of SGC-7901 cells through suppression of EMT and NF-κB/Snail signal pathway. Based on these findings, COE may be considered a novel anticancer agent for the treatment of metastasis in gastric cancer.

MET receptor is a potential therapeutic target in high grade cervical cancer

Cervical cancer is one of the leading causes of death among women suffering from tumors. Current treatment options are insufficient. Here, we investigated the MET receptor as a potential molecular target in advanced cervical cancer. Downregulation of MET receptor expression via RNA interference in different cervical carcinoma cell lines dramatically decreased tumor growth and forced tumor differentiation in vivo. MET receptor silencing also led to a dramatic decrease in cell size and a decrease in proliferation rate under normal and stress conditions. MET receptor downregulation also resulted in decreased cyclin D1 and c-myc levels but did not increase apoptosis. Subsequent experiments showed that downregulation of the MET receptor decreased the expression of a key regulator of the epithelial-to-mesenchymal transition, SLUG. and increased the expression of E-cadherin, a hallmark of the epithelial phenotype. Moreover, MET downregulation impairs expression and signaling of CXCR4 receptor, responsible for invasive phenotype. Taken together, our results strongly suggest that the MET receptor influences the oncogenic properties of cervical carcinoma cells in vitro and in vivo. These findings highlight a unique role of the MET receptor in cervical carcinoma cells and indicate the MET receptor as a potential therapeutic target for advanced cervical carcinoma.

Fascin Overexpression Promotes Cholangiocarcinoma RBE Cell Proliferation, Migration, and Invasion

Fascin is overexpressed in various tumor tissues and is closely related to tumor metastasis and invasion. However, the role of fascin in cholangiocarcinoma RBE cells has not been clearly reported. This study aimed to establish a cholangiocarcinoma cell line with stable and high expression of fascin to observe the effect of fascin on cell proliferation, migration, and invasion. A fascin overexpression vector, pcDNA3.1-Fascin, was constructed and transfected into the human cholangiocarcinoma RBE cell line. The results of real-time polymerase chain reaction, Western blot, and immunofluorescence indicated that fascin was steadily and highly expressed in RBE cells. The results of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide and colony formation assay indicated that upregulated fascin expression could enhance cholangiocarcinoma cell proliferation. The results of wound healing assay and transwell assay indicated that fascin could promote cholangiocarcinoma cell migration and invasion, and a further study found that the nuclear factor-κB signaling pathway was activated after upregulation of fascin, whereas E-cadherin expression in these cells was significantly decreased. Additionally, E-cadherin expression was significantly increased after inhibiting nuclear factor-κB activity using inhibitor or small interfering RNA, and E-cadherin expression was decreased by fascin overexpression after nuclear factor-κB inhibition, suggesting that nuclear factor-κB signaling pathway was not involved in the regulation of E-cadherin by fascin. In summary, the results of this study demonstrated that fascin effectively promoted cholangiocarcinoma RBE cell proliferation, migration, and invasion. This study provides evidence for fascin as a potential target in the treatment of cholangiocarcinoma.

TWEAK enhances TGF-β-induced epithelial-mesenchymal transition in human bronchial epithelial cells

BACKGROUND

Chronic airway inflammatory disorders, such as asthma, are characterized by airway inflammation and remodeling. Chronic inflammation and damage to the airway epithelium cause airway remodeling, which is associated with improper epithelial repair, and is characterized by elevated expression of transforming growth factor-β (TGF-β). Epithelial-mesenchymal transition (EMT) is an important mechanism during embryonic development and tissue remodeling whereby epithelial cells gain the capacity to increase motility by down-regulation of epithelial markers and up-regulation of mesenchymal markers. TGF-β is a central inducer of EMT, and TGF-β-induced EMT is enhanced by pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α) and interleukin-1β. We investigated whether the pro-inflammatory cytokine TWEAK (TNF-like weak inducer of apoptosis) enhanced TGF-β1-induced EMT in the human bronchial epithelial cell line BEAS-2B.

METHODS

Quantitative RT-PCR and western blotting were used to define alterations in epithelial and mesenchymal marker expression in BEAS-2B cells. The cells were assessed for 48 h after stimulation with TGF-β1 alone or in combination with TWEAK.

RESULTS

TGF-β1 induced spindle-like morphology and loss of cell contact, and reduced the expression of epithelial marker E-cadherin and increased the expression of mesenchymal markers N-cadherin and vimentin. Our data, for the first time, show that TWEAK reduced the expression of E-cadherin, and that co-treatment with TGF-β1 and TWEAK enhanced the TGF-β1-induced features of EMT. Moreover, hyaluronan synthase 2 expression was up-regulated by a combination with TGF-β1 and TWEAK, but not TNF-α. We also demonstrated that the Smad, p38 MAPK, and NF-κB signaling pathways, and the transcriptional repressor ZEB2 might mediate N-cadherin up-regulation by TGF-β1 in combination with TWEAK.

CONCLUSIONS

These findings suggest that the pro-inflammatory cytokine TWEAK and TGF-β1 have synergistic effects in EMT and may contribute to chronic airway changes and remodeling.

Inhibition of colon cancer cell growth by nanoemulsion carrying gold nanoparticles and lycopene

Lycopene (LP), an important functional compound in tomatoes, and gold nanoparticles (AN), have received considerable attention as potential candidates for cancer therapy. However, the extreme instability and poor bioavailability of LP limits its in vivo application. This study intends to develop a nanoemulsion system incorporating both LP and AN, and to study the possible synergistic effects on the inhibition of the HT-29 colon cancer cell line. LP-nanogold nanoemulsion containing Tween 80 as an emulsifier was prepared, followed by characterization using transmission electron microscopy (TEM), dynamic light scattering (DLS) analysis, ultraviolet spectroscopy, and zeta potential analysis. The particle size as determined by TEM and DLS was 21.3±3.7 nm and 25.0±4.2 nm for nanoemulsion and 4.7±1.1 nm and 3.3±0.6 nm for AN, while the zeta potential of nanoemulsion and AN was -32.2±1.8 mV and -48.5±2.7 mV, respectively. Compared with the control treatment, both the combo (AN 10 ppm plus LP 12 μM) and nanoemulsion (AN 0.16 ppm plus LP 0.4 μM) treatments resulted in a five- and 15-fold rise in early apoptotic cells of HT-29, respectively. Also, the nanoemulsion significantly reduced the expressions of procaspases 8, 3, and 9, as well as PARP-1 and Bcl-2, while Bax expression was enhanced. A fivefold decline in the migration capability of HT-29 cells was observed for this nanoemulsion when compared to control, with the invasion-associated markers being significantly reversed through the upregulation of the epithelial marker E-cadherin and downregulation of Akt, nuclear factor kappa B, pro-matrix metalloproteinase (MMP)-2, and active MMP-9 expressions. The TEM images revealed that numerous nanoemulsion-filled vacuoles invaded cytosol and converged into the mitochondria, resulting in an abnormally elongated morphology with reduced cristae and matrix contents, demonstrating a possible passive targeting effect. The nanoemulsion containing vacuoles were engulfed and internalized by the nuclear membrane envelop for subsequent invasion into the nucleoli. Taken together, LP-nanogold nanoemulsion could provide synergistic effects at AN and LP doses 250 and 120 times lower than that in the combo treatment, respectively, demonstrating the potential of nanoemulsion developed in this study for a possible application in colon cancer therapy.

Mannose-mediated inhibitory effects of PA-MSHA on invasion and metastasis of hepatocellular carcinoma via EGFR/Akt/IκBβ/NF-κB pathway

BACKGROUND & AIMS

Elevation of high-mannose glycans is a common feature of malignant cells and has been suggested to be the basis for alternative cancer therapy for several years. Here we want to investigate the antitumour effect of pseudomonas aeruginosa-mannosesensitive haemagglutinin (PA-MSHA), a genetically engineered heat-inactivated PA strain with mannose-sensitive binding activity, on hepatocellular carcinoma (HCC).

METHODS

Tumourigenicity and metastatic potentials of HCC were studied after PA-MSHA treatment by utilizing the in vitro/in vivo model of HCC. Expression of apoptosis-associated proteins and epithelial-mesenchymal transition (EMT) related genes were evaluated, and possible signalling pathways involved were investigated.

RESULTS

PA-MSHA induced significant cell proliferation inhibition and cell cycle arrest of HCC through decreasing the levels of cyclins D1, cyclins E, CDK2, CDK4, proliferating cell nuclear antigen (PCNA), and increasing the level of p21 and p27. Moreover, PA-MSHA suppressed the invasion, migration and adhesion of HCC through inhibiting epithelial-mesenchymal transition (EMT). PA-MSHA also inhibited EGFR/Akt/IκBβ/NF-κB pathway and overexpression of NF-κB significantly abrogated PA-MSHA induced EMT inhibition. In addition, competitive inhibition of the mannose binding activity of PA-MSHA by D-mannose significantly blocked its effect on cell cycle arrest and EMT. PA-MSHA also abrogated lung metastasis of HCC and significantly inhibited tumour growth in the in vivo study.

CONCLUSIONS

Our study demonstrated the essential role of EGFR/Akt/IκBβ/NF-κB pathway in the inhibitory effect of PA-MSHA on invasion and metastasis of HCC through suppressing EMT, and revealed an attractive prospect of PA-MSHA as a novel candidate agent in the treatment of HCC.

Simultaneous silencing of XIAP and survivin causes partial mesenchymal-epithelial transition of human pancreatic cancer cells via the PTEN/PI3K/Akt pathway

Pancreatic cancer has one of the highest mortality rates among malignant tumors and is characterized by rapid invasion, early metastasis and chemoresistance. X-linked inhibitor of apoptosis (XIAP) and survivin are two of the most important members of the IAP family. Previous studies have shown that XIAP and survivin were overexpressed in pancreatic cancer and were closely associated with cell proliferation and chemoresistance to gemcitabine. In the present study, stable inhibition of XIAP and survivin in Panc-1 cells was performed using lentivirus-carried short hairpin RNAs. The expression of XIAP, survivin, E-cadherin, Slug, phosphatase and tensin homolog (PTEN) and phosphorylated Akt was then measured. In addition, cell proliferation, apoptosis, invasion and migration were assessed. The results showed that stable inhibition of XIAP and survivin expression in Panc-1 cells significantly reduced cell proliferation, increased apoptosis and partially reversed the epithelial-mesenchymal transition (EMT). Furthermore, the results of the present study demonstrated that the partial reversal of the EMT was accompanied by inhibited cell invasion and migration as well as increased chemosensitivity to gemcitabine in pancreatic cancer cells; this was indicated to be mediated via the PTEN/phosphatidylinositol 3-kinase/Akt signaling pathway. In conclusion, these results suggested that simultaneous inhibition of XIAP and survivin may be a promising strategy for the treatment of pancreatic cancer.