Mesenchyme Forkhead 1 (FOXC2) plays a key role in metastasis and is associated with aggressive basal-like breast cancers

Aqueous Huaier Extract Suppresses Gastric Cancer Metastasis and Epithelial to Mesenchymal Transition by Targeting Twist

Trametes robiniophila Murr. (Huaier) is a widely used anti-cancer agent in China. Strong evidence for the anti-proliferative activity of Huaier has been reported; however, its anti-metastatic potential against gastric cancer (GC) as well as its underlying mechanism of action are unknown. Here, we show that treatment with an aqueous Huaier extract over a range of concentrations significantly suppressed both the invasiveness and migratory ability of GC cells. Huaier could also partly reverse the epithelial-mesenchymal transition (EMT), as characterized by increased expression of the epithelial marker E-cadherin and decreased expression of the mesenchymal markers N-cadherin and vimentin. In addition, Huaier-treated cells expressed lower levels of Twist compared to untreated controls, and overexpression of Twist via transfection could partially abolish the anti-metastatic activity of Huaier. Furthermore, elevated Twist expression was correlated with an advanced TNM stage, a high rate of lymph node metastasis, and reduced disease-free survival in GC patients. These findings reveal a novel anti-metastatic mechanism for Huaier, which inhibits the EMT by targeting Twist, suggesting its potential application against a GC relapse.

Decrypting the PAK4 transcriptome profile in mammary tumor forming cells using Next Generation Sequencing

The p-21 Activated Kinase 4 (PAK4) protein kinase is implicated in many cancers, including breast cancer. Overexpression of PAK4 is sufficient to cause mouse mammary epithelial cells (iMMECs) to become tumorigenic. To gain insight into the long-term gene expression changes that occur downstream to PAK4, we performed Next Generation Sequencing of RNA collected from PAK4 overexpressing iMMECs and wild-type iMMECs. We identified a list of genes whose expression levels were altered in response to PAK4 overexpression in iMMECs. Some of these genes, including FoxC2 and ParvB, are consistent with a role for PAK4 in cancer. In addition, PAK4 regulates many genes that are frequently associated with the inflammatory response, raising the possibility that there is a connection between PAK4, inflammation, and the tumor microenvironment. This study delineates the PAK4 transcriptome profile in transformed mammary cells and can provide translational utility in other types of cancers as well.

MicroRNA Let-7g Directly Targets Forkhead Box C2 (FOXC2) to Modulate Bone Metastasis in Breast Cancer

Aberrantly expressed microRNAs have been implicated in lots of cancers. Reduced amounts of let-7g have been found in breast cancer tissues. The function of let-7g in bone metastasis of breast cancer remains poorly understood. This study is to explore the significance of let-7g and its novel target gene in bone metastasis of breast cancer.

The expression of let-7g or forkhead box C2 (FOXC2) was measured in human clinical breast cancer tissues with bone metastasis by using quantitative real-time Polymerase Chain Reaction (qRT-PCR). After transfection with let-7g or anti-let-7g in breast cancer cell linesMDA-MB-231or SK-BR3, qRT-PCR and Western blot were done to test the levels of let-7g and FOXC2. The effect of anti-let-7g and/ or FOXC2 RNA interference (RNAi) on cell migration in breast cancer cells was evaluated by using wound healing assay.

Clinically, qRT-PCR showed that FOXC2 levels were higher in breast cancer tissues with bone metastasis than those in their noncancerous counterparts. Let-7g was showed to be negatively correlated with FOXC2 in human breast cancer samples with bone metastasis. We found that enforced expression of let-7g reduced levels of FOXC2 protein by using Western blot in MDA-MB-231 cells. Conversely, anti-let-7g enhanced levels of FOXC2 in SK-BR3 cells. In terms of function, anti-let-7g accelerated migration of SK-BR3 cells. Interestingly, FOXC2 RNAi abrogated anti-let-7g-mediated migration in breast cancer cells. Thus, we conclude that let-7g suppresses cell migration through targeting FOXC2 in breast cancer. Our finding provides a new perspective for understanding the mechanism of bone metastasis in breast cancer.

Pituitary stem cell regulation: who is pulling the strings?

The pituitary gland plays a pivotal role in the endocrine system, steering fundamental processes of growth, metabolism, reproduction and coping with stress. The adult pituitary contains resident stem cells, which are highly quiescent in homeostatic conditions. However, the cells show marked signs of activation during processes of increased cell remodeling in the gland, including maturation at neonatal age, adaptation to physiological demands, regeneration upon injury and growth of local tumors. Although functions of pituitary stem cells are slowly but gradually uncovered, their regulation largely remains virgin territory. Since postnatal stem cells in general reiterate embryonic developmental pathways, attention is first being given to regulatory networks involved in pituitary embryogenesis. Here, we give an overview of the current knowledge on the NOTCH, WNT, epithelial-mesenchymal transition, SHH and Hippo pathways in the pituitary stem/progenitor cell compartment during various (activation) conditions from embryonic over neonatal to adult age. Most information comes from expression analyses of molecular components belonging to these networks, whereas functional extrapolation is still very limited. From this overview, it emerges that the 'big five' embryonic pathways are indeed reiterated in the stem cells of the 'lazy' homeostatic postnatal pituitary, further magnified en route to activation in more energetic, physiological and pathological remodeling conditions. Increasing the knowledge on the molecular players that pull the regulatory strings of the pituitary stem cells will not only provide further fundamental insight in postnatal pituitary homeostasis and activation, but also clues toward the development of regenerative ideas for improving treatment of pituitary deficiency and tumors.

MicroRNA-182 promotes proliferation and metastasis by targeting FOXF2 in triple-negative breast cancer

Triple-negative breast cancer (TNBC), the most aggressive subtype of breast cancer (BC), is characterized as high proliferation, young age and poor prognosis. MicroRNA-182 (miR-182) was reported to have oncogenic potential in many cancers. We aimed to elucidate pathobiological effects of miR-182 expression by targeting forkhead-box F2 (FOXF2) in TNBC. In this study, we explored the functional role of miR-182 expression in TNBC. Quantitative real-time PCR (qRT-PCR) was applied to evaluate the expression of miR-182 in cell lines and tissues. A series of in vitro and in vivo assays were performed in the MCF-7 and MDA-MB-231 cell lines with miR-182 overexpression. Luciferase reporter assays and western blot analysis were used to identify FOXF2 as the direct and functional target of miR-182. In TNBC tissues and cell lines, we found that miR-182 was significantly upregulated. Transwell assay showed that re-expression of miR-182 increased cell migration and invasion abilities and MTT assay showed that it promoted cell growth in vitro. In vivo assay, re-expression of miR-182 significantly increase tumor volume and enhanced instant metastasis in the lungs of mice. Besides, FOXF2 was identified as a direct and functional target of miR-182. These results indicated that miR-182 plays an important role in the initiation and progression of TNBC by targeting FOXF2 and the miR-182/FOXF2 axis may present a new therapeutic strategy for TNBC in the future.

Epithelial requirement for in vitro proliferation and xenograft growth and metastasis of MDA-MB-468 human breast cancer cells: oncogenic rather than tumor-suppressive role of E-cadherin

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) is associated with downregulated E-cadherin and frequently with decreased proliferation. Proliferation may be restored in secondary metastases by mesenchymal-to-epithelial transition (MET). We tested whether E-cadherin maintains epithelial proliferation in MDA-MB-468 breast cancer cells, facilitating metastatic colonization in severe combined immunodeficiency (SCID) mice.

METHODS

EMT/MET markers were assessed in xenograft tumors by immunohistochemistry. Stable E-cadherin manipulation was effected by transfection and verified by Western blotting, immunocytochemistry, and quantitative polymerase chain reaction (qPCR). Effects of E-cadherin manipulation on proliferation and chemomigration were assessed in vitro by performing sulforhodamine B assays and Transwell assays, respectively. Invasion was assessed by Matrigel outgrowth; growth in vivo was assessed in SCID mice; and EMT status was assessed by qPCR. Hypoxic response of E-cadherin knockdown cell lines was assessed by qPCR after hypoxic culture. Repeated measures analysis of variance (ANOVA), one- and two-way ANOVA with posttests, and paired Student's t tests were performed to determine significance (p < 0.05).

RESULTS

EMT occurred at the necrotic interface of MDA-MB-468 xenografts in regions of hypoxia. Extratumoral deposits (vascular and lymphatic inclusions, local and axillary nodes, and lung metastases) strongly expressed E-cadherin. MDA-MB-468 cells overexpressing E-cadherin were more proliferative and less migratory in vitro, whereas E-cadherin knockdown (short hairpin CDH1 [shCDH1]) cells were more migratory and invasive, less proliferative, and took longer to form tumors. shCDH1-MDA-MB-468 xenografts did not contain the hypoxia-induced necrotic areas observed in wild-type (WT) and shSCR-MDA-MB-468 tumors, but they did not exhibit an impaired hypoxic response in vitro. Although vimentin expression was not stimulated by E-cadherin knockdown in 2D or 3D cultures, xenografts of these cells were globally vimentin-positive rather than exhibiting regional EMT, and they expressed higher SNA1 than their in vitro counterparts. E-cadherin suppression caused a trend toward reduced lung metastasis, whereas E-cadherin overexpression resulted in the reverse trend, consistent with the increased proliferation rate and predominantly epithelial phenotype of MDA-MB-468 cells outside the primary xenograft. This was also originally observed in WT xenografts. Furthermore, we found that patients with breast cancer that expressed E-cadherin were more likely to have metastases.

CONCLUSIONS

E-cadherin expression promotes growth of primary breast tumors and conceivably the formation of metastases, supporting a role for MET in metastasis. E-cadherin needs to be reevaluated as a tumor suppressor.

The Implications and Future Perspectives of Nanomedicine for Cancer Stem Cell Targeted Therapies

Cancer stem cells (CSCs) are believed to exhibit distinctive self-renewal, proliferation, and differentiation capabilities, and thus play a significant role in various aspects of cancer. CSCs have significant impacts on the progression of tumors, drug resistance, recurrence and metastasis in different types of malignancies. Due to their primary role, most researchers have focused on developing anti-CSC therapeutic strategies, and tremendous efforts have been put to explore methods for selective eradication of these therapeutically resistant CSCs. In recent years, many reports have shown the use of CSCs-specific approaches such as ATP-binding cassette (ABC) transporters, blockade of self-renewal and survival of CSCs, CSCs surface markers targeted drugs delivery and eradication of the tumor microenvironment. Also, various therapeutic agents such as small molecule drugs, nucleic acids, and antibodies are said to destroy CSCs selectively. Targeted drug delivery holds the key to the success of most of the anti-CSCs based drugs/therapies. The convention CSCs-specific therapeutic agents, suffer from various problems. For instance, limited water solubility, small circulation time and inconsistent stability of conventional therapeutic agents have significantly limited their efficacy. Recent advancement in the drug delivery technology has demonstrated that specially designed nanocarrier-based drug delivery approaches (nanomedicine) can be useful in delivering sufficient amount of drug molecules even in the most interiors of CSCs niches and thus can overcome the limitations associated with the conventional free drug delivery methods. The nanomedicine has also been promising in designing effective therapeutic regime against pump-mediated drug resistance (ATP-driven) and reduces detrimental effects on normal stem cells. Here we focus on the biological processes regulating CSCs' drug resistance and various strategies developed so far to deal with them. We also review the various nanomedicine approaches developed so far to overcome these CSCs related issues and their future perspectives.

EMT and MET: necessary or permissive for metastasis?

Epithelial‐to‐mesenchymal transition (EMT) and its reverse mesenchymal‐to‐epithelial transition (MET) have been suggested to play crucial roles in metastatic dissemination of carcinomas. These phenotypic transitions between states are not binary. Instead, carcinoma cells often exhibit a spectrum of epithelial/mesenchymal phenotype(s). While epithelial/mesenchymal plasticity has been observed preclinically and clinically, whether any of these phenotypic transitions are indispensable for metastatic outgrowth remains an unanswered question. Here, we focus on epithelial/mesenchymal plasticity in metastatic dissemination and propose alternative mechanisms for successful dissemination and metastases beyond the traditional EMT/MET view. We highlight multiple hypotheses that can help reconcile conflicting observations, and outline the next set of key questions that can offer valuable insights into mechanisms of metastasis in multiple tumor models.

The Emerging Roles of Forkhead Box (FOX) Proteins in Osteosarcoma

Osteosarcoma is the most common bone cancer primarily occurring in children and young adults. Over the past few years, the deregulation of a superfamily transcription factors, known as forkhead box (FOX) proteins, has been demonstrated to contribute to the pathogenesis of osteosarcoma. Molecular mechanism studies have demonstrated that FOX family proteins participate in a variety of signaling pathways and that their expression can be regulated by multiple factors. The dysfunction of FOX genes can alter osteosarcoma cell differentiation, metastasis and progression. In this review, we summarized the evidence that FOX genes play direct or indirect roles in the development and progression of osteosarcoma, and evaluated the emerging role of FOX proteins as targets for therapeutic intervention.

Up-Regulation of FOXC2 and FOXQ1 Is Associated with The Progression of Gastric-Type Adenocarcinoma

OBJECTIVE

Forkhead box (FOX) proteins are important regulators of the epithelial-to-mesenchymal transition (EMT), which is the main mechanism of cancer metastasis. Different studies have shown their potential involvement in progression of cancer in different tissues such as breast, ovary and colorectum. In this study, we aimed to analyze the expression of genes encoding two FOX proteins in gastric adenocarcinoma.

MATERIALS AND METHODS

In this experimental case-control study, the expression of FOXC2 and FOXQ1 was examined in 31 gastric adenocarcinoma tumors and 31 normal adjacent gastric tissues by reverse transcription polymerase chain reaction (PCR).

RESULTS

The expression of both genes was significantly up-regulated in gastric adenocarcinoma tumors compared with the normal tissues (P<0.05). The differential expression of these two genes was also correlated with the grade of tumors (P<0.01).

CONCLUSION

We show that up-regulation of FOXC2 and FOXQ1 are likely to be involved in the progression of gastric adenocarcinoma.

VEGFA links self-renewal and metastasis by inducing Sox2 to repress miR-452, driving Slug

Cancer stem cells (CSC) appear to have increased metastatic potential, but mechanisms underlying this are poorly defined. Here we show that VEGFA induction of Sox2 promotes EMT and tumor metastasis. In breast lines and primary cancer culture, VEGFA rapidly upregulates SOX2 expression, leading to SNAI2 induction, EMT, increased invasion and metastasis. We show Sox2 downregulates miR-452, which acts as a novel metastasis suppressor to directly target the SNAI2 3′-untranslated region (3′-UTR). VEGFA stimulates Sox2- and Slug-dependent cell invasion. VEGFA increases lung metastasis in vivo, and this is abrogated by miR-452 overexpression. Furthermore, SNAI2 transduction rescues metastasis suppression by miR-452. Thus, in addition to its angiogenic action, VEGFA upregulates Sox2 to drive stem cell expansion, together with miR-452 loss and Slug upregulation, providing a novel mechanism whereby cancer stem cells acquire metastatic potential. Prior work showed EMT transcription factor overexpression upregulates CSC. Present work indicates that stemness and metastasis are a two-way street: Sox2, a major mediator of CSC self-renewal, also governs the metastatic process.

Model-based unsupervised learning informs metformin-induced cell-migration inhibition through an AMPK-independent mechanism in breast cancer

We demonstrate that model-based unsupervised learning can uniquely discriminate single-cell subpopulations by their gene expression distributions, which in turn allow us to identify specific genes for focused functional studies. This method was applied to MDA-MB-231 breast cancer cells treated with the antidiabetic drug metformin, which is being repurposed for treatment of triple-negative breast cancer. Unsupervised learning identified a cluster of metformin-treated cells characterized by a significant suppression of 230 genes (p-value < 2E-16). This analysis corroborates known studies of metformin action: a) pathway analysis indicated known mechanisms related to metformin action, including the citric acid (TCA) cycle, oxidative phosphorylation, and mitochondrial dysfunction (p-value < 1E-9); b) 70% of these 230 genes were functionally implicated in metformin response; c) among remaining lesser functionally-studied genes for metformin-response was CDC42, down-regulated in breast cancer treated with metformin. However, CDC42's mechanisms in metformin response remained unclear. Our functional studies showed that CDC42 was involved in metformin-induced inhibition of cell proliferation and cell migration mediated through an AMPK-independent mechanism. Our results points to 230 genes that might serve as metformin response signatures, which needs to be tested in patients treated with metformin and, further investigation of CDC42 and AMPK-independence's role in metformin's anticancer mechanisms.

Breast cancer stem cell: the roles and therapeutic implications

Breast cancers have been increasingly recognized as malignancies displaying frequent inter- and intra-tumor heterogeneity. This heterogeneity is represented by diverse subtypes and complexity within tumors, and impinges on response to therapy, metastasis, and prognosis. Cancer stem cells (CSCs), a subpopulation of cancer cells endowed with self-renewal and differentiation capacity, have been suggested to contribute to tumor heterogeneity. The CSC concept posits a hierarchical organization of tumors, at the apex of which are stem cells that drive tumor initiation, progression, and recurrence. In breast cancer, CSCs have been proposed to contribute to malignant progression, suggesting that targeting breast cancer stem cells (BCSCs) may improve treatment efficacy. Currently, several markers have been reported to identify BCSCs. However, there is objective variability with respect to the frequency and phenotype of BCSCs among different breast cancer cell lines and patients, and the regulatory mechanisms of BCSCs remain unclear. In this review, we summarize current literature about the diversity of BCSC markers, the roles of BCSCs in tumor development, and the regulatory mechanisms of BCSCs. We also highlight the most recent advances in BCSC targeting therapies and the challenges in translating the knowledge into clinical practice.

Epigenetic regulation of HGF/Met receptor axis is critical for the outgrowth of bone metastasis from breast carcinoma

Our translational research deals with the influence of microenvironment on the phenotype and colonization of bone metastases from breast carcinoma, and on pre-metastatic niche formation. The aim of the present study was to clarify the origin of hepatocyte growth factor (HGF), ligand of Met receptor, the control of the axis HGF/Met by DNA methylation, and its importance for the nexus supportive cells-metastatic cells and for metastasis outgrowth. In bone metastasis of the 1833-xenograft model, DNA methyltransferase blockade using the chemotherapic drug 5-aza-2′-deoxycytidine (decitabine) strongly reduced the expression of HGF/Met receptor axis and of E-cadherin, with decrease of metastasis wideness and osteolysis, prolonging mice survival. Thus, DNA methylation events acted as commanders of breast carcinoma cells metastatizing to bone influencing the epithelial phenotype. HGF emerged as a bone-marrow stimulus, and the exosomes seemed to furnish HGF to metastatic cells. In fact, decitabine treatment similarly affected some markers of these microvesicles and HGF, indicating that its supply to recipient cells was prevented. Notably, in bone metastasis the hypomethylation of HGF, Met and E-cadherin promoters did not appear responsible for their elevated expression, but we suggest the involvement of hypermethylated regulators and of Wwox oncosuppressor, the latter being affected by decitabine. Wwox expression increased under decitabine strongly localizing in nuclei of bone metastases. We hypothesize a role of Wwox in Met activity since in vitro Wwox overexpression downregulated the level of nuclear-Met protein fragment and Met stability, also under long exposure of 1833 cells to decitabine. HGF enhanced phosphoMet and the activity in nuclei, an effect partially prevented by decitabine. Altogether, the data indicated the importance to target the tumor microenvironment by blocking epigenetic mechanisms, which control critical events for colonization such as HGF/Met axis and Wwox, as therapy of bone metastasis.

Serum and tissue markers in colorectal cancer: State of art

Colorectal cancer (CRC) represents one of the most commonly diagnosed cancers worldwide. It is the second leading cause of cancer death in Western Countries. In the last decade, the survival of patients with metastatic CRC has improved dramatically. Due to the advent of new drugs (irinotecan and oxaliplatin) and target therapies (i.e. bevacizumab, cetuximab, panitumab, aflibercept and regorafenib), the median overall survival has risen from about 12 mo in the mid nineties to 30 mo recently. Molecular studies have recently widened the opportunity for testing new possible markers, but actually, only few markers can be recommended for practical use in clinic. In the next future, the hope is to have a complete panel of clinical biomarkers to use in every setting of CRC disease, and at the same time: 1) to receive information about prognostic significance by their expression and 2) to be oriented in the choice of the adequate treatment. Moreover, molecular analyses have shown that the natural history of all CRCs is not the same. Individual patients with same stage tumors may have different long-term prognosis and response to therapy. In addition, some prognostic variables are likely to be more important than others. Here we review the role of serum and tissue markers according to the recently published English literature. This paper is an extension of the article "Biological and clinical markers in colorectal cancer: state of art" by Cappellani A published in Jan 2010.

FOXC1 is associated with estrogen receptor alpha and affects sensitivity of tamoxifen treatment in breast cancer

FOXC1 is a member of Forkhead box transcription factors that participates in embryonic development and tumorigenesis. Our previous study demonstrated that FOXC1 was highly expressed in triple‐negative breast cancer. However, it remains unclear what is the relation between FOXC1 and ERα and if FOXC1 regulates expression of ERα. To explore relation between FOXC1 and ERα and discover regulation of ERα expression by FOXC1 in breast cancer, we analyzed data assembled in the Oncomine and TCGA, and found that there was significantly higher FOXC1 expression in estrogen receptor‐negative breast cancer than that in estrogen receptor‐positive breast cancer. Overexpression of FOXC1 reduced expression of ERα and cellular responses to estradiol (E2) and tamoxifen in the MCF‐7 FOXC1 and T47D FOXC1 cells, while knockdown of FOXC1 induced expression of ERα and improved responses to estradiol (E2) and tamoxifen in BT549 FOXC1 shRNA and HCC1806 FOXC1 shRNA cells. In addition, overexpression of FOXC1 reduced expression of progesterone receptor (PR), Insulin receptor substrate 1 (IRS1), and XBP1 (X‐Box Binding Protein 1) and significantly reduced luciferase activity caused by E2 using ERE luciferase reporter assay. These results suggested that FOXC1 regulated expression of ERα and affected sensitivity of tamoxifen treatment in breast cancer, and that FOXC1 may be used as a potential therapeutic target in ERα‐negative breast cancer.

Phosphorylation of serine 367 of FOXC2 by p38 regulates ZEB1 and breast cancer metastasis, without impacting primary tumor growth

Metastatic competence is contingent upon the aberrant activation of a latent embryonic program, known as the epithelial-mesenchymal transition (EMT), which bestows stem cell properties as well as migratory and invasive capabilities upon differentiated tumor cells. We recently identified the transcription factor FOXC2 as a downstream effector of multiple EMT programs, independent of the EMT-inducing stimulus, and as a key player linking EMT, stem cell traits and metastatic competence in breast cancer. As such, FOXC2 could serve as a potential therapeutic target to attenuate metastasis. However, as FOXC2 is a transcription factor, it is difficult to target by conventional means such as small-molecule inhibitors. Herein, we identify the serine/threonine-specific kinase p38 as a druggable upstream regulator of FOXC2 stability and function that elicits phosphorylation of FOXC2 at serine 367 (S367). Using an orthotopic syngeneic mouse tumor model, we make the striking observation that inhibition of p38-FOXC2 signaling selectively attenuates metastasis without impacting primary tumor growth. In this model, circulating tumor cell numbers are significantly reduced in mice treated with the p38 inhibitor SB203580, relative to vehicle-treated counterparts. Accordingly, genetic or pharmacological inhibition of p38 decreases FOXC2 protein levels, reverts the EMT phenotype and compromises stem cell attributes in vitro. We also identify the EMT-regulator ZEB1-known to directly repress E-cadherin/CDH1-as a downstream target of FOXC2, critically dependent on its activation by p38. Consistent with the notion that activation of the p38-FOXC2 signaling axis represents a critical juncture in the acquisition of metastatic competence, the phosphomimetic FOXC2(S367E) mutant is refractory to p38 inhibition both in vitro and in vivo, whereas the non-phosphorylatable FOXC2(S367A) mutant fails to elicit EMT and upregulate ZEB1. Collectively, our data demonstrate that FOXC2 regulates EMT, stem cell traits, ZEB1 expression and metastasis in a p38-dependent manner, and attest to the potential utility of p38 inhibitors as antimetastatic agents.

Multimodal tumor suppression by miR-302 cluster in melanoma and colon cancer

The miR-302 family is one of the main groups of microRNAs, which are highly expressed in embryonic stem cells (ESCs). Previous reports have indicated that miR-302 can reduce the proliferation rate of some cancer cells while compromising on their oncogenic potential at the same time without having the same effect on normal somatic cells. In this study we aimed to further investigate the role of the miR-302 cluster in multiple cancer signaling pathways using A-375 melanoma and HT-29 colorectal cancer cells. Our results indicate that the miR-302 cluster has the potential to modulate oncogenic properties of cancer cells through inhibition of proliferation, angiogenesis and invasion, and through reversal of the epithelial-to-mesenchymal transition (EMT) in these cells. We showed for the first time that overexpression of miR-302 cluster sensitized A-375 and HT-29 cells to hypoxia and also to the selective BRAF inhibitor vemurafenib. MiR-302 is a pleiotropically acting miRNA family which may have significant implications in controlling cancer progression and invasion. It acts through a reprogramming process, which has a global effect on a multitude of cellular pathways and events. We propose that reprogramming of cancer cells by epigenetic factors, especially miRNAs might provide an efficient tool for controlling cancer and especially for those with more invasive nature.

Biomarkers for EMT and MET in breast cancer: An update

Metastasis and recurrence are the leading cause of mortality due to breast cancer, but the underlying mechanisms are still poorly understood. Understanding the breast cancer metastasis mechanism is important for early diagnosis and treatment of breast cancer. The seeding and growth of breast cancer cells at sites distinct from the primary tumor is a complex and multistage process. Recently, it has been reported that the epithelial-mesenchymal transition (EMT) and the mesenchymal-epithelial transition (MET) are the main mechanisms for breast cancer metastasis. During EMT, carcinoma cells shed their differentiated epithelial characteristics, including cell-cell adhesion, polarity and lack of motility, and acquire mesenchymal traits, including motility and invasiveness. This review has summarized the studies of known EMT biomarkers in the context of breast cancer progression. These biomarkers include EMT-related genes, proteins, microRNAs and kinases. In general, the findings of these studies suggest that EMT markers are associated with the invasion and metastasis of breast cancer. Further studies on the link between EMT markers and breast cancer will contribute to identify biomarkers for predicting early breast cancer metastasis as well as to provide new ideas for the treatment of breast cancer.

Tackling Cancer Stem Cells via Inhibition of EMT Transcription Factors

Cancer stem cell (CSC) has become recognized for its role in both tumorigenesis and poor patient prognosis in recent years. Traditional therapeutics are unable to effectively eliminate this group of cells from the bulk population of cancer cells, allowing CSCs to persist posttreatment and thus propagate into secondary tumors. The therapeutic potential of eliminating CSCs, to decrease tumor relapse, has created a demand for identifying mechanisms that directly target and eliminate cancer stem cells. Molecular profiling has shown that cancer cells and tumors that exhibit the CSC phenotype also express genes associated with the epithelial-to-mesenchymal transition (EMT) feature. Ample evidence has demonstrated that upregulation of master transcription factors (TFs) accounting for the EMT process such as Snail/Slug and Twist can reprogram cancer cells from differentiated to stem-like status. Despite being appealing therapeutic targets for tackling CSCs, pharmacological approaches that directly target EMT-TFs remain impossible. In this review, we will summarize recent advances in the regulation of Snail/Slug and Twist at transcriptional, translational, and posttranslational levels and discuss the clinical implication and application for EMT blockade as a promising strategy for CSC targeting.

Dysregulated JAK2 expression by TrkC promotes metastasis potential, and EMT program of metastatic breast cancer

Metastatic breast cancers are aggressive tumors associated with high levels of epithelial-mesenchymal transition (EMT) markers, activation of IL6/JAK2/STAT3 and PI3K/AKT pathways for cell growth, mobility, invasion, metastasis, and CSC status. We identified a new molecular and functional network present in metastasis that regulates and coordinates with TrkC. Inhibition of SOCS3-mediated JAK2 degradation by TrkC increases total JAK2/STAT3 expression, and then leads to upregulation of Twist-1 through activation of JAK2/STAT3 cascade. Also, TrkC increases secretion and expression of IL-6, suggesting that this autocrine loop generated by TrkC maintains the mesenchymal state by continued activation of the JAK2/STAT3 cascade and upregulation of Twist expression. Moreover, TrkC interacts with the c-Src/Jak2 complex, which increases Twist-1 and Twist-2 levels via regulation of JAK2/STAT3 activation and JAK2/STAT3 expression. Furthermore, TrkC enhances metastatic potential of breast cancer via induction of EMT by upregulating Twist-1 and Twist-2. Additionally, TrkC significantly enhances the ability of breast cancer cells to form pulmonary metastases and primary tumor formation. Unexpectedly, we found that TrkC expression and clinical breast tumor pathological phenotypes show significant correlation. These findings suggest that TrkC plays a central role in tumorigenicity, metastasis, and self-renewal traits of metastatic breast cancer.

The expressions of NEDD9 and E-cadherin correlate with metastasis and poor prognosis in triple-negative breast cancer patients

Background

Neural precursor cell expressed, developmentally downregulated 9 (NEDD9), a member of Crk-associated substrate family, is involved in cancer cell adhesion, migration, invasion, and epithelial–mesenchymal transition. E-cadherin is a key event in the cellular invasion during the epithelial–mesenchymal transition mechanism. The aim of this study was to evaluate the association among NEDD9 expression, E-cadherin expression, and survival in triple-negative breast cancer (TNBC) patients.

Methods

NEDD9 and E-cadherin expressions were analyzed by immunohistochemistry in 106 TNBC patients and 120 non-TNBC patients. And the association of clinicopathological factors with survival was analyzed using Kaplan–Meier analysis and Cox regression in TNBC patients.

Results

The results revealed that the rate of increased expression of NEDD9 and reduced expression of E-cadherin was significantly higher in TNBC group than that in non-TNBC group (P<0.001, both). Comparison of features between TNBC and non-TNBC groups showed that histological type (P=0.026) and lymph node metastasis (P=0.001) were significantly different. Correlation analysis showed that positive NEDD9 expression and negative E-cadherin expression were significantly correlated with lymph node metastasis and tumor-node-metastasis stage (P<0.05). In addition, the enhanced NEDD9 expression was significantly associated with a reduced 5-year survival for TNBC patients (overall survival [OS]: P=0.013; disease-free survival [DFS]: P=0.021). Negative E-cadherin expression showed a significantly worse 5-year OS and DFS (OS: P=0.011; DFS: P=0.012). Multivariate analysis showed that lymph node metastasis (OS: P=0.006; DFS: P=0.004), tumor-node-metastasis stage (OS: P=0.012; DFS: P=0.001), NEDD9 (OS: P=0.046; DFS: P=0.022), and E-cadherin (OS: P=0.022; DFS: P=0.025) independently predicted a poor prognosis of OS and DFS. Moreover, patients with NEDD9-positive/E-cadherin-negative expression had a significantly worse outcome than other groups (OS: P=0.004; DFS: P=0.001).

Conclusion

Our finding demonstrated the potential value of NEDD9 and E-cadherin expression levels as prognostic molecular markers and a target for new therapies for TNBC patients.

Antitumor Effect of Programmed Death-1 (PD-1) Blockade in Humanized the NOG-MHC Double Knockout Mouse

PURPOSE

Humanized mouse models using NOD/Shi-scid-IL2rγ^null (NOG) and NOD/LtSz-scid IL2rγ^null (NSG) mouse are associated with several limitations, such as long incubation time for stem cell engraftment and the development of xenograft versus host disease in mice injected with peripheral blood mononuclear cells (PBMCs). To solve problems, we used humanized major histocompatibility class I- and class II-deficient NOG mice (referred to as NOG-dKO) to evaluate the antitumor effect of anti-programmed death-1 (PD-1) antibody.

EXPERIMENTAL DESIGN

Humanized NOG-dKO mice, in which human PBMCs and human lymphoma cell line SCC-3, or glioblastoma cell line U87 were transplanted, were used as an immunotherapy model to investigate the effect of anti-PD-1 antibody. A biosimilar anti-PD-1 mAb generated in our laboratory was administered to humanized NOG-dKO mice transplanted with tumors.

RESULTS

Within 4 weeks after transplantation, human CD45⁺ cells in antibody-treated mice constituted approximately 70% of spleen cells. The injection of anti-PD-1 antibody reduced by more 50% the size of SCC-3 and U87 tumors. In addition, induction of CTLs against SCC-3 cells and upregulation of natural killer cell activity was observed in the antibody-treated group. Tumor-infiltrating lymphocyte profiling showed that more exhausted marker (PD1⁺TIM3⁺LAG3⁺) positive T cells maintained in anti-PD-1 antibody-treated tumor. A greater number of CD8⁺ and granzyme-producing T cells infiltrated the tumor in mice treated with the anti-PD-1 antibody.

CONCLUSIONS

These results suggest that NOG-dKO mice might serve as a good humanized immunotherapy model to evaluate the efficacy of anti-PD-1 antibody prior to the clinical treatment. Clin Cancer Res; 23(1); 149-58. ©2016 AACR.

Mesenchymal Stromal Cells Epithelial Transition Induced by Renal Tubular Cells-Derived Extracellular Vesicles

Mesenchymal-epithelial interactions play an important role in renal tubular morphogenesis and in maintaining the structure of the kidney. The aim of this study was to investigate whether extracellular vesicles (EVs) produced by human renal proximal tubular epithelial cells (RPTECs) may induce mesenchymal-epithelial transition of bone marrow-derived mesenchymal stromal cells (MSCs). To test this hypothesis, we characterized the phenotype and the RNA content of EVs and we evaluated the in vitro uptake and activity of EVs on MSCs. MicroRNA (miRNA) analysis suggested the possible implication of the miR-200 family carried by EVs in the epithelial commitment of MSCs. Bone marrow-derived MSCs were incubated with EVs, or RPTEC-derived total conditioned medium, or conditioned medium depleted of EVs. As a positive control, MSCs were co-cultured in a transwell system with RPTECs. Epithelial commitment of MSCs was assessed by real time PCR and by immunofluorescence analysis of cellular expression of specific mesenchymal and epithelial markers. After one week of incubation with EVs and total conditioned medium, we observed mesenchymal-epithelial transition in MSCs. Stimulation with conditioned medium depleted of EVs did not induce any change in mesenchymal and epithelial gene expression. Since EVs were found to contain the miR-200 family, we transfected MSCs using synthetic miR-200 mimics. After one week of transfection, mesenchymal-epithelial transition was induced in MSCs. In conclusion, miR-200 carrying EVs released from RPTECs induce the epithelial commitment of MSCs that may contribute to their regenerative potential. Based on experiments of MSC transfection with miR-200 mimics, we suggested that the miR-200 family may be involved in mesenchymal-epithelial transition of MSCs.

Mechanisms of TGFβ-Induced Epithelial-Mesenchymal Transition

Transitory phenotypic changes such as the epithelial–mesenchymal transition (EMT) help embryonic cells to generate migratory descendants that populate new sites and establish the distinct tissues in the developing embryo. The mesenchymal descendants of diverse epithelia also participate in the wound healing response of adult tissues, and facilitate the progression of cancer. EMT can be induced by several extracellular cues in the microenvironment of a given epithelial tissue. One such cue, transforming growth factor β (TGFβ), prominently induces EMT via a group of specific transcription factors. The potency of TGFβ is partly based on its ability to perform two parallel molecular functions, i.e. to induce the expression of growth factors, cytokines and chemokines, which sequentially and in a complementary manner help to establish and maintain the EMT, and to mediate signaling crosstalk with other developmental signaling pathways, thus promoting changes in cell differentiation. The molecules that are activated by TGFβ signaling or act as cooperating partners of this pathway are impossible to exhaust within a single coherent and contemporary report. Here, we present selected examples to illustrate the key principles of the circuits that control EMT under the influence of TGFβ.

Epithelial-mesenchymal transition (EMT) and metastasis: yes, no, maybe?

An epithelial to mesenchymal transition (EMT) is a process of cell remodeling critical during embryonic development and organogenesis. During an EMT, epithelial cells lose their polarized organization and acquire migratory and invasive capabilities. While a plethora of experimental results have indicated that manipulating an EMT also affects cancer metastasis, its reverse process, a mesenchymal to epithelial transition (MET), seems to support metastatic outgrowth in distant organs. Moreover, recent reports investigating cancer cells circulating in the blood stream or employing genetic lineage-tracing have questioned a critical role of an EMT in metastasis formation. Hence, we need to better understand the molecular networks underlying the cell plasticity conferred by an EMT or a MET and its functional contribution to malignant tumor progression.

Cdk5 and Foxc2--a new relationship in the lymphatic vasculature

Lymphatic vessel dysfunction is associated with various pathologic conditions, including immunologic disorders, lymphedema, as well as tumor dissemination. Yet, the knowledge about the regulation of lymphatic vessel development is still limited. Our study elucidates cyclin dependent kinase 5 (Cdk5) as an essential player in the development of lymphatic vessels. Deletion of Cdk5 in the mouse endothelium results in severe lymphedema formation and embryonic lethality. On the mechanistic level, we show that Cdk5 phosphorylates the forkhead transcription factor Foxc2 which regulates Foxc2-dependent transcription. In summary, our study elucidates the Cdk5-Foxc2 interaction as a critical regulator of lymphatic vessel development.

Mechanotransduction activates canonical Wnt/β-catenin signaling to promote lymphatic vascular patterning and the development of lymphatic and lymphovenous valves

In this study, Cha et al. show that the Wnt/β-catenin signaling pathway is the link between fluid flow and lymphatic vascular morphogenesis. They provide a molecular and structural framework to study mammalian lymphatic vasculature by demonstrating that mechanical stimulation is a critical regulator of lymphatic vascular development via activation of Wnt/β-catenin signaling.

Lymphatic vasculature regulates fluid homeostasis by returning interstitial fluid to blood circulation. Lymphatic endothelial cells (LECs) are the building blocks of the entire lymphatic vasculature. LECs originate as a homogeneous population of cells predominantly from the embryonic veins and undergo stepwise morphogenesis to become the lymphatic capillaries, collecting vessels or valves. The molecular mechanisms underlying the morphogenesis of the lymphatic vasculature remain to be fully understood. Here we show that canonical Wnt/β-catenin signaling is necessary for lymphatic vascular morphogenesis. Lymphatic vascular-specific ablation of β-catenin in mice prevents the formation of lymphatic and lymphovenous valves. Additionally, lymphatic vessel patterning is defective in these mice, with abnormal recruitment of mural cells. We found that oscillatory shear stress (OSS), which promotes lymphatic vessel maturation, triggers Wnt/β-catenin signaling in LECs. In turn, Wnt/β-catenin signaling controls the expression of several molecules, including the lymphedema-associated transcription factor FOXC2. Importantly, FOXC2 completely rescues the lymphatic vessel patterning defects in mice lacking β-catenin. Thus, our work reveals that mechanical stimulation is a critical regulator of lymphatic vascular development via activation of Wnt/β-catenin signaling and, in turn, FOXC2.

Notch promotes tumor metastasis in a prostate-specific Pten-null mouse model

Although Notch signaling is deregulated in prostate cancer, the role of this pathway in disease development and progression is not fully understood. Here, we analyzed 2 human prostate cancer data sets and found that higher Notch signaling correlates with increased metastatic potential and worse disease survival rates. We used the Pten-null mouse prostate cancer model to investigate the function of Notch signaling in the initiation and progression of prostate cancer. Disruption of the transcription factor RBPJ in Pten-null mice revealed that endogenous canonical Notch signaling is not required for disease initiation and progression. However, augmentation of Notch activity in this model promoted both proliferation and apoptosis of prostate epithelial cells, which collectively reduced the primary tumor burden. The increase in cellular apoptosis was linked to DNA damage-induced p53 activation. Despite a reduced primary tumor burden, Notch activation in Pten-null mice promoted epithelial-mesenchymal transition and FOXC2-dependent tumor metastases but did not confer resistance to androgen deprivation. Notch activation also resulted in transformation of seminal vesicle epithelial cells in Pten-null mice. Our study highlights a multifaceted role for Notch signaling in distinct aspects of prostate cancer biology and supports Notch as a potential therapeutic target for metastatic prostate cancer.

Stem cell technology in breast cancer: current status and potential applications

Breast cancer, the leading cause of cancer among females, is supported by the presence of a rare subset of undifferentiated cells within the tumor, identified as breast cancer stem cells (BCSCs). BCSCs underlie the mechanisms of tumor initiation and sustenance and are implicated in the dissemination of the primary tumor to metastatic sites, as they have been found circulating in the blood of breast cancer patients. The discovery of BCSCs has generated a great amount of interest among the scientific community toward their isolation, molecular characterization, and therapeutic targeting. In this review, after summarizing the literature on molecular characterization of BCSCs and methodologies used for their isolation, we will focus on recent data supporting their molecular and functional heterogeneity. Additionally, following a synopsis of the latest approaches for BCSC targeting, we will specifically emphasize on the therapeutic use of naïve or engineered normal stem cells in the treatment of breast cancer and present contradictory findings challenging their safety.

FOXC2 regulates the G2/M transition of stem cell-rich breast cancer cells and sensitizes them to PLK1 inhibition

Cancer cells with stem cell properties (CSCs) underpin the chemotherapy resistance and high therapeutic failure of triple-negative breast cancers (TNBCs). Even though CSCs are known to proliferate more slowly, they are sensitive to inhibitors of G2/M kinases such as polo-like kinase 1 (PLK1). Understanding the cell cycle regulatory mechanisms of CSCs will help target these cells more efficiently. Herein, we identify a novel role for the transcription factor FOXC2, which is mostly expressed in CSCs, in the regulation of cell cycle of CSC-enriched breast cancer cells. We demonstrate that FOXC2 expression is regulated in a cell cycle-dependent manner, with FOXC2 protein levels accumulating in G2, and rapidly decreasing during mitosis. Knockdown of FOXC2 in CSC-enriched TNBC cells delays mitotic entry without significantly affecting the overall proliferation rate of these cells. Moreover, PLK1 activity is important for FOXC2 protein stability, since PLK1 inhibition reduces FOXC2 protein levels. Indeed, FOXC2 expressing CSC-enriched TNBC cells are sensitive to PLK1 inhibition. Collectively, our findings demonstrate a novel role for FOXC2 as a regulator of the G2/M transition and elucidate the reason for the observed sensitivity of CSC-enriched breast cancer cells to PLK1 inhibitor.

The Therapeutic Targets of miRNA in Hepatic Cancer Stem Cells

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide malignancy and the third leading cause of cancer death in patients. Several studies demonstrated that hepatic cancer stem cells (HCSCs), also called tumor-initiating cells, are involved in regulation of HCC initiation, tumor progression, metastasis development, and drug resistance. Despite the extensive research, the underlying mechanisms by which HCSCs are regulated remain still unclear. MicroRNAs (miRNAs) are able to regulate a lot of biological processes such as self-renewal and pluripotency of HCSCs, representing a new promising strategy for treatment of HCC chemotherapy-resistant tumors. In this review, we synthesize the latest findings on therapeutic regulation of HCSCs by miRNAs, in order to highlight the perspective of novel miRNA-based anticancer therapies for HCC treatment.

Circulating Tumor Cells: A Window Into Tumor Development and Therapeutic Effectiveness

BACKGROUND

Circulating tumor cells (CTCs) are an important diagnostic tool for understanding the metastatic process and the development of cancer.

METHODS

This review covers the background, relevance, and potential limitations of CTCs as a measurement of cancer progression and how information derived from CTCs may affect treatment efficacy. It also highlights the difficulties of characterizing these rare cells due to the limited cell surface molecules unique to CTCs and each particular type of cancer.

RESULTS

The analysis of cancer in real time, through the measure of the number of CTCs in a " liquid" biopsy specimen, gives us the ability to monitor the therapeutic efficacy of treatments and possibly the metastatic potential of a tumor.

CONCLUSIONS

Through novel and innovative techniques yielding encouraging results, including microfluidic techniques, isolating and molecularly analyzing CTCs are becoming a reality. CTCs hold promise for understanding how tumors work and potentially aiding in their demise.

Inflammation fuels tumor progress and metastasis

Inflammation is a beneficial response that can remove pathogens, repair injured tissue and restore homeostasis to damaged tissues and organs. However, increasing evidence indicate that chronic inflammation plays a pivotal role in tumor development, as well as progression, metastasis, and resistance to chemotherapy. We will review the current knowledge regarding the contribution of inflammation to epithelial mesenchymal transition. We will also provide some perspectives on the relationship between ER-stress signals and metabolism, and the role of these processes in the development of inflammation.

Inhibition of FOXC2 restores epithelial phenotype and drug sensitivity in prostate cancer cells with stem-cell properties

Advanced prostate adenocarcinomas enriched in stem-cell features, as well as variant androgen receptor (AR)-negative neuroendocrine (NE)/small-cell prostate cancers are difficult to treat, and account for up to 30% of prostate cancer-related deaths every year. While existing therapies for prostate cancer such as androgen deprivation therapy (ADT), destroy the bulk of the AR-positive cells within the tumor, eradicating this population eventually leads to castration-resistance, owing to the continued survival of AR^-/lo stem-like cells. In this study, we identified a critical nexus between p38MAPK signaling, and the transcription factor Forkhead Box Protein C2 (FOXC2) known to promote cancer stem-cells and metastasis. We demonstrate that prostate cancer cells that are insensitive to ADT, as well as high-grade/NE prostate tumors, are characterized by elevated FOXC2, and that targeting FOXC2 using a well-tolerated p38 inhibitor restores epithelial attributes and ADT-sensitivity, and reduces the shedding of circulating tumor cells in vivo with significant shrinkage in the tumor mass. This study thus specifies a tangible mechanism to target the AR^-/lo population of prostate cancer cells with stem-cell properties.

Post-transcriptional Control of Tumor Cell Autonomous Metastatic Potential by CCR4-NOT Deadenylase CNOT7

Accumulating evidence supports the role of an aberrant transcriptome as a driver of metastatic potential. Deadenylation is a general regulatory node for post-transcriptional control by microRNAs and other determinants of RNA stability. Previously, we demonstrated that the CCR4-NOT scaffold component Cnot2 is an inherited metastasis susceptibility gene. In this study, using orthotopic metastasis assays and genetically engineered mouse models, we show that one of the enzymatic subunits of the CCR4-NOT complex, Cnot7, is also a metastasis modifying gene. We demonstrate that higher expression of Cnot7 drives tumor cell autonomous metastatic potential, which requires its deadenylase activity. Furthermore, metastasis promotion by CNOT7 is dependent on interaction with CNOT1 and TOB1. CNOT7 ribonucleoprotein-immunoprecipitation (RIP) and integrated transcriptome wide analyses reveal that CNOT7-regulated transcripts are enriched for a tripartite 3'UTR motif bound by RNA-binding proteins known to complex with CNOT7, TOB1, and CNOT1. Collectively, our data support a model of CNOT7, TOB1, CNOT1, and RNA-binding proteins collectively exerting post-transcriptional control on a metastasis suppressive transcriptional program to drive tumor cell metastasis.

Epithelial-Mesenchymal Transition (EMT) and Regulation of EMT Factors by Steroid Nuclear Receptors in Breast Cancer: A Review and in Silico Investigation

Steroid Nuclear Receptors (SNRs) are transcription factors of the nuclear receptor super-family. Estrogen Receptor (ERα) is the best-studied and has a seminal role in the clinic both as a prognostic marker but also as a predictor of response to anti-estrogenic therapies. Progesterone Receptor (PR) is also used in the clinic but with a more debatable prognostic role and the role of the four other SNRs, ERβ, Androgen Receptor (AR), Glucocorticoid Receptor (GR) and Mineralocorticoid Receptor (MR), is starting only to be appreciated. ERα, but also to a certain degree the other SNRs, have been reported to be involved in virtually every cancer-enabling process, both promoting and impeding carcinogenesis. Epithelial-Mesenchymal Transition (EMT) and the reverse Mesenchymal Epithelial Transition (MET) are such carcinogenesis-enabling processes with important roles in invasion and metastasis initiation but also establishment of tumor in the metastatic site. EMT is governed by several signal transduction pathways culminating in core transcription factors of the process, such as Snail, Slug, ZEB1 and ZEB2, and Twist, among others. This paper will discuss direct regulation of these core transcription factors by SNRs in breast cancer. Interrogation of publicly available databases for binding sites of SNRs on promoters of core EMT factors will also be included in an attempt to fill gaps where other experimental data are not available.

Prognostic value of high FoxC2 expression in resectable non-small cell lung cancer, alone or in combination with E-cadherin expression

Background

FoxC2 is an epithelial–mesenchymal transition (EMT) regulator which induces metastasis. The purpose of this study is to assess the prognostic value of FoxC2 expression in non-small cell lung cancer (NSCLC), alone or in combination with E-cadherin expression.

Methods

A retrospective study was conducted using immunohistochemistry to investigate FoxC2 and E-cadherin expression in a cohort of 309 patients with surgically resected NSCLCs. The prognostic value of FoxC2 and E-cadherin on overall survival (OS) and recurrence-free survival (RFS) was determined by Kaplan-Meier analysis and Cox proportional hazard models.

Results

High FoxC2 expression was detected in 26.5 % of tumors, and significantly correlated with tobacco use (p = 0.047), adenocarcinoma (p = 0.008) and nodal involvement (p < 0.001). Univariate analysis revealed its association with OS (p = 0.036) and RFS (p = 0.011). By multivariate analysis, high FoxC2 expression lost its significance as an independent predictor of recurrence (p = 0.077), while TNM stage, nodal status and the presence of high FoxC2 and impaired E-cadherin expression retained independent prognostic significance in relation to both OS and RFS. Subset analyses indicated that high FoxC2 expression was significantly associated with disease outcome in node-positive, but not in node-negative patients.

Conclusion

Evaluation of FoxC2 expression, alone or in combination with E-cadherin expression, may help to stratify NSCLC patients for risk of disease progression, pointing to this EMT regulator as a potential prognostic marker.

Downregulation of Foxc2 enhances apoptosis induced by 5-fluorouracil through activation of MAPK and AKT pathways in colorectal cancer

The chemotherapy drug 5-fluorouracil (5-FU) is fundamental for the treatment of colorectal cancer (CRC); however, drug resistance to 5-FU may occasionally occur. Abnormal expression of Forkhead box C2 gene (Foxc2) has been identified in several human cancers, but the role of Foxc2 in the progression of CRC remains unclear. The present study established a stable Foxc2-short hairpin (sh)RNA cell line, which was confirmed by western blot analysis and quantitative polymerase chain reaction. The Foxc2-shRNA cells were treated with 5-FU and the cell viability was determined by an MTT assay. Western blot analysis was performed to investigate the signaling pathway involved in 5-FU treatment. The present study identified that 5-FU increased the percentage of apoptotic CRC cells among the Foxc2/RNA interference-transfected cells compared with cells transfected with an empty vector. Therefore, the downregulation of Foxc2, induced by 5-FU, may enhance apoptosis by the downregulation of apoptotic factors, including B cell lymphoma-2 and pro-caspase-3, in Foxc2-shRNA CRC cells. Furthermore, the mitogen-activated protein kinase (MAPK) and phosphatidylinositide 3-kinases/protein kinase B (PI3K/AKT) pathways were essential for the sensitization effect of Foxc2 to 5-FU treatment. Overall, these findings reveal the mechanisms behind Foxc2 depletion and 5-FU treatment of CRC and suggest that Foxc2 enhances resistance to apoptosis, induced by 5-FU, through the activation of MAPK and P13K/AKT pathways, and may serve as a valuable clinical prognostic marker for CRC.

Sustained proliferation in cancer: Mechanisms and novel therapeutic targets

Proliferation is an important part of cancer development and progression. This is manifest by altered expression and/or activity of cell cycle related proteins. Constitutive activation of many signal transduction pathways also stimulates cell growth. Early steps in tumor development are associated with a fibrogenic response and the development of a hypoxic environment which favors the survival and proliferation of cancer stem cells. Part of the survival strategy of cancer stem cells may manifested by alterations in cell metabolism. Once tumors appear, growth and metastasis may be supported by overproduction of appropriate hormones (in hormonally dependent cancers), by promoting angiogenesis, by undergoing epithelial to mesenchymal transition, by triggering autophagy, and by taking cues from surrounding stromal cells. A number of natural compounds (e.g., curcumin, resveratrol, indole-3-carbinol, brassinin, sulforaphane, epigallocatechin-3-gallate, genistein, ellagitannins, lycopene and quercetin) have been found to inhibit one or more pathways that contribute to proliferation (e.g., hypoxia inducible factor 1, nuclear factor kappa B, phosphoinositide 3 kinase/Akt, insulin-like growth factor receptor 1, Wnt, cell cycle associated proteins, as well as androgen and estrogen receptor signaling). These data, in combination with bioinformatics analyses, will be very important for identifying signaling pathways and molecular targets that may provide early diagnostic markers and/or critical targets for the development of new drugs or drug combinations that block tumor formation and progression.

Combinatorial interventions inhibit TGFβ-driven epithelial-to-mesenchymal transition and support hybrid cellular phenotypes

Epithelial-to-mesenchymal transition (EMT) is a developmental process hijacked by cancer cells to leave the primary tumor site, invade surrounding tissue and establish distant metastases. A hallmark of EMT is the loss of E-cadherin expression, and one major signal for the induction of EMT is transforming growth factor beta (TGFβ), which is dysregulated in up to 40% of hepatocellular carcinoma (HCC). We aim to identify network perturbations that suppress TGFβ-driven EMT, with the goal of suppressing invasive properties of cancer cells. We use a systems-level Boolean dynamic model of EMT to systematically screen individual and combination perturbations (inhibition or constitutive activation of up to four nodes). We use a recently developed network control approach to understand the mechanism through which the combinatorial interventions suppress EMT. We test the results of our in silico analysis using siRNA. Our model predicts that targeting key elements of feedback loops in combination with the SMAD complex is more effective than suppressing the SMAD complex alone. We demonstrate experimentally that expression of a majority of these elements is enriched in mesenchymal relative to epithelial phenotype HCC cell lines. An siRNA screen of the predicted combinations confirms that many targeting strategies suppress TGFβ-driven EMT measured by E-cadherin expression and cell migration. Our analysis reveals that some perturbations give rise to hybrid states intermediate to the epithelial and mesenchymal states. Our results indicate that EMT is driven by an interconnected signaling network and many apparently successful single interventions may lead to steady states that are in-between epithelial and mesenchymal states. As these putative hybrid or partial EMT states may retain invasive properties, our results suggest that combinatorial therapies are necessary to fully suppress invasive properties of tumor cells.

Overexpression of transcription factor FOXC2 in cultured human podocytes upregulates injury markers and increases motility

Obesity and diabetes-related kidney diseases associate with renal failure and cardiovascular morbidity, and represent a major health issue worldwide. However, the molecular mechanisms leading to their development remain poorly understood. We observed increased expression of transcription factor FoxC2 in the podocytes of obese Zucker rats that are insulin resistant and albuminuric. We also found that depletion of adiponectin, an adipocyte-derived hormone whose secretion is decreased in obesity, upregulated FOXC2 in differentiated human podocytes in vitro. Overexpression of FOXC2 in cultured human podocytes led to increased nuclear expression of FOXC2 associated with a change of cellular morphology. This was accompanied by upregulation of vimentin, a key mesenchymal marker, and active beta-catenin, associated with podocyte injury. We also observed re-organization of the actin cytoskeleton, disrupted localization of the tight junction protein ZO-1, and increased motility of podocytes overexpressing FOXC2. These data indicate that the expression of FOXC2 in podocytes needs to be tightly regulated, and that its overexpression induces a chain of cellular events leading to podocyte dysfunction. These changes may lead to podocyte detachment and depletion ultimately contributing to albuminuria. We also suggest a novel molecular mechanism linking obesity-induced decrease in adiponectin to podocyte dysfunction via upregulation of FOXC2.

Twist-BRD4 complex: potential drug target for basal-like breast cancer

As an important basic helix-loop-helix (bHLH) transcription factor, Twist associates with several physiological processes such as mesodermal development, and pathological processes such as Saethre-Chotzen syndrome. During cancer progression, Twist induces epithelial-mesenchymal transition (EMT), potentiating cancer cell invasion and metastasis. Although many studies have revealed its multiple biological roles, it remained unclear how Twist transcriptionally activates targeted genes. Recently we discovered tip60-mediated Twist di-acetylation in the ''histone H4-mimic'' GK-X-GK motif. The di-acetylated Twist recruits BRD4 and related transcriptional components to super-enhancer of its targeted genes during progression of basal-like breast cancer (BLBC). Here, we review this new advance of regulation and functional mechanism of Twist.