UDP-glucose accelerates SNAI1 mRNA decay and impairs lung cancer metastasis.

Cancer metastasis is the primary cause of morbidity and mortality, and accounts for up to 95% of cancer-related deaths1. Cancer cells often reprogram their metabolism to efficiently support cell proliferation and survival2,3. However, whether and how those metabolic alterations contribute to the migration of tumour cells remain largely unknown. UDP-glucose 6-dehydrogenase (UGDH) is a key enzyme in the uronic acid pathway, and converts UDP-glucose to UDP-glucuronic acid4. Here we show that, after activation of EGFR, UGDH is phosphorylated at tyrosine 473 in human lung cancer cells. Phosphorylated UGDH interacts with Hu antigen R (HuR) and converts UDP-glucose to UDP-glucuronic acid, which attenuates the UDP-glucose-mediated inhibition of the association of HuR with SNAI1 mRNA and therefore enhances the stability of SNAI1 mRNA. Increased production of SNAIL initiates the epithelial-mesenchymal transition, thus promoting the migration of tumour cells and lung cancer metastasis. In addition, phosphorylation of UGDH at tyrosine 473 correlates with metastatic recurrence and poor prognosis of patients with lung cancer. Our findings reveal a tumour-suppressive role of UDP-glucose in lung cancer metastasis and uncover a mechanism by which UGDH promotes tumour metastasis by increasing the stability of SNAI1 mRNA.

S100A4/Nonmuscle Myosin IIA/p53 Axis Contributes to Aggressive Features in Ovarian High-Grade Serous Carcinoma.

S100A4 is a small calcium-binding protein that exerts its biological functions by interacting with nonmuscle myosin IIA (NMIIA) and p53. Although S100A4 promotes metastasis in several tumors, little is known about its involvement in the progression of ovarian high-grade serous carcinomas (HGSCs). Herein, we focused on functional roles of the S100A4/NMIIA/p53 axis in these tumors. In HGSC cell lines harboring mutant p53, knockdown (KD) of S100A4 reduced the expression of several epithelial-mesenchymal transition/cancer stem cell markers and the ALDH1high population, consistent with an inhibition of stemness features. S100A4-KD also increased apoptosis, decreased cell proliferation, and accelerated cell mobility. This was accompanied by increased Snail expression, which, in turn, was likely due to loss of p53 function. In contrast, specific inhibition of NMIIA by blebbistatin induced phenotypes that-with the exception of cell proliferation and mobility-were opposite to those observed in S100A4-KD cells. In clinical samples, cytoplasmic and/or nuclear interactions between S100A4, NMIIA, and mutant p53 were observed. In addition, high expression of S100A4, but not NMIIA or p53, was a significant and independent unfavorable prognostic factor in HGSC patients. These findings suggest that, via its interaction with NMIIA and p53, overexpressed S100A4 may induce epithelial-mesenchymal transition/cancer stem cell properties in HGSC and elicit several other tumor-associated phenotypes.

PAK1 promotes proliferation, migration and invasion of hepatocellular carcinoma by facilitating EMT via directly up-regulating Snail.

BACKGROUND: Hepatocellular carcinoma (HCC) is a primary cause of cancer mortality. PAK1 plays key roles in many types of cancers. However, the role of PAK1 in HCC is not clear. METHODS: qRT-PCR and Western blotting were used to determine expressions of PAK1, Snail and epithelial mesenchymal transition (EMT)-related proteins. Luciferase reporter assay was used to measure the interaction between PAK1 and Snail. Wound healing, transwell, colony formation assays and flow cytometry were used to assess cell migration, invasion, proliferation and apoptosis. Mouse tumor xenograft model was used to determine the effect of PAK1 on tumor growth in vivo. RESULTS: PAK1 and Snail were up-regulated in HCC cells. PAK1 knockdown suppressed cell proliferation, migration and invasion, and increased apoptosis of HCC cells. PAK1 knockdown also inhibited tumor growth in vivo. Mechanistically, PAK1 promoted EMT by targeting Snail. Knockdown of PAK1 could up-regulate pro-apoptotic proteins but down-regulate proliferation-related proteins via suppressing ß-catenin signaling pathway. CONCLUSION: PAK1 promotes EMT process by increasing Snail, and facilitates progression of HCC by activating ß-catenin pathway.

Sphingosine 1-phosphate signaling induces SNAI2 expression to promote cell invasion in breast cancer cells.

Epithelial-mesenchymal transition (EMT) is a critical process implicated in the initial stage of cancer metastasis, which is the major cause of tumor recurrence and mortality. Although key transcription factors that regulate EMT, such as snail family transcriptional repressor 2 (SNAI2), are well characterized, the upstream signaling pathways controlling these transcriptional mediators are largely unknown, which limits therapeutic strategies. Sphingosine 1-phosphate (S1P) is a bioactive lipid mediator, generated by sphingosine kinases (SPHK1 and SPHK2), that mainly exerts its effects by binding to the following 5 GPCRs: S1P1 to S1P5. S1P signaling has been reported to regulate different aspects of cancer progression including cell proliferation, apoptosis, and migration; nevertheless, its role in cancer metastasis, specifically via EMT, is not established. Here we show that SPHK1 expression correlates significantly with EMT score in breast cancer cell lines, and with SNAI2 in patient-derived breast tumors. Cell-based assays demonstrate that S1P can rapidly up-regulate the expression of SNAI2 in breast cancer cells via the activation of cognate receptors S1P2 and S1P3. Knockdown studies suggest that S1P2 and S1P3 mediate this effect by activating myocardin-related transcription factor A (MRTF-A) and yes-associated protein (YAP), respectively. Michigan Cancer Foundation 7 cells stably overexpressing S1P2 or S1P3 exhibit a more invasive phenotype, when compared to control cells. Taken together, our findings suggest that S1P produced by SPHK1 induces SNAI2 expression via S1P2-YAP and S1P3-MRTF-A pathways, leading to enhanced cell invasion. Cumulatively, this study reveals a novel mechanism by which S1P activates parallel pathways that regulate the expression of SNAI2, a master regulator of EMT, and provides new insights into druggable therapeutic targets that may limit cancer metastasis. Wang, W., Hind, T., Lam, B. W. S., Herr, D. R. Sphingosine 1-phosphate signaling induces SNAI2 expression to promote cell invasion in breast cancer cells.

Blockade of ERK1/2 by U0126 alleviates uric acid-induced EMT and tubular cell injury in rats with hyperuricemic nephropathy.

Extracellular signal-regulated kinases 1 and 2 (ERK1/2) are serine/threonine kinases and function as regulators of cellular proliferation and differentiation. Recently, we demonstrated that inhibition of ERK1/2 alleviates the development and progression of hyperuricemia nephropathy (HN). However, its potential roles in uric acid-induced tubular epithelial-mesenchymal transition (EMT) and tubular epithelial cell injury are unknown. In this study, we showed that hyperuricemic injury induced EMT as characterized by downregulation of E-cadherin and upregulation of vimentin and Snail1 in a rat model of HN. This was coincident with epithelial cells arrested at the G2/M phase of cell cycle, activation of Notch1/Jagged-1 and Wnt/ß-catenin signaling pathways, and upregulation of matrix metalloproteinase-2 (MMP-2) and MMP-9. Administration of U0126, a selective inhibitor of ERK1/2, blocked all these responses. U0126 was also effective in inhibiting renal tubular cell injury, as shown by decreased expression of lipocalin-2 and kidney injury molecule-1 and active forms of caspase-3. U0126 or ERK1/2 siRNA can inhibit tubular cell EMT and cell apoptosis as characterized with decreased expression of cleaved caspase-3. Moreover, ERK1/2 inhibition suppressed hyperuricemic injury-induced oxidative stress as indicated by decreased malondialdehyde and increased superoxide dismutase. Collectively, ERK1/2 inhibition-elicited renal protection is associated with inhibition of EMT through inactivation of multiple signaling pathways and matrix metalloproteinases, as well as attenuation of renal tubule injury by enhancing cellular resistance to oxidative stress.

IGF-1/IGF-1R blockade ameliorates diabetic kidney disease through normalizing Snail1 expression in a mouse model.

This study investigated the role of insulin-like growth factor-1/insulin-like growth factor-1 receptor (IGF-1/IGF-1R) in the genesis and progression of diabetic kidney disease (DKD) in a streptozotocin (STZ)-induced mouse diabetes model. We showed elevated IGF-1 expression in the DKD kidneys after 16 wk of diabetic onset. Intraperitoneal administration of IGF-1R inhibitor (glycogen synthase kinase-3ß, GSK4529) from week 8 to week 16 postdiabetes induction ameliorated urinary albumin excretion and kidney histological changes due to diabetes, including amelioration of glomerulomegaly, inflammatory infiltration, and tubulointerstitial fibrosis. The GSK4529 treatment also attenuated alterations in renal tubular expression of E-cad and matrix protein fibronectin. Moreover, renal fibrosis in DKD (without treatment) was associated with Snail1 overexpression that was effectively prevented by IGF-1R inhibition. Further experiments in cultured renal epithelial cells (NRK) showed that IGF-1 silencing reproduced in vivo effects of IGF-1R inhibition with markedly attenuated Snail1 expression and near normalization of the Ecad1 and fibronectin expression pattern. Further Snail1 silencing prevented high-glucose-induced changes without affecting IGF-1 expression, consistent with Snail1 acting downstream to IGF-1. The antifibrotic effects were also shown with benazepril or insulin treatment but to a much lesser degree. In summary, in STZ-induced diabetic mice, activation of IGF-1 in diabetic kidneys induces fibrogenesis through Snail1 upregulation. The diabetes-related histological and functional changes, as well as fibrogenesis, can be attenuated by IGF-1/IGF-1R inhibition.

A novel tumor-based epithelial-to-mesenchymal transition score that associates with prognosis and metastasis in patients with Stage II/III colorectal cancer.

It is increasingly appreciated that host factors within the tumor center and microenvironment play a key role in dictating colorectal cancer (CRC) outcomes. As a result, the metastatic process has now been defined as a result of epithelial-mesenchymal transition (EMT). Establishment of the role of EMT within the tumor center and its effect on the tumor microenvironment would be beneficial for prognosis and therapeutic intervention in CRC. The present study assessed five immunohistochemical EMT markers within the tumor center on a 185 Stage II/III CRC patient tissue microarray. In 185 patients with CRC, cytoplasmic snail (HR 1.94 95% confidence interval [CI] 1.15-3.29, p = 0.012) and a novel combined EMT score (HR 3.86 95% CI 2.17-6.86, p < 0.001) were associated with decreased cancer-specific survival. The combined EMT score was also associated with increased tumor budding (p = 0.046), and systemic inflammation (p = 0.007), as well as decreased memory T-cells within the stroma (p = 0.030) and at the invasive margin (p = 0.035). Furthermore, the combined EMT score was associated with cancer-specific survival independent of TNM-stage (HR 4.12 95% CI 2.30-7.39, p < 0.001). In conclusion, a novel combined EMT score stratifies patient's survival in Stage II/III CRC and associates with key factors of tumor metastasis. Therefore, the combined EMT score could be used to identify patients at risk of micrometastases and who may benefit from standard adjuvant therapy, potentially in combination with EMT blockade.

Expression of epithelial-mesenchymal transition regulators TWIST, SLUG and SNAIL in follicular thyroid tumours may relate to widely invasive, poorly differentiated and distant metastasis.

AIMS: To assess the expression of epithelial-mesenchymal transition (EMT) regulators in follicular thyroid tumours. METHODS AND RESULTS: The expression of E-cadherin (E-CAD) and transcription factors TWIST, SLUG and SNAIL in follicular thyroid tumours was examined by immunohistochemistry in tissue samples, including 18 follicular adenomas (FA), 12 minimally invasive follicular thyroid carcinomas (MI-FTC), 16 widely invasive follicular thyroid carcinomas (WI-FTC), 10 poorly differentiated follicular thyroid carcinomas (PDTC) and six anaplastic thyroid carcinomas (ATC). Metastatic tumour tissues from six of these cases were also examined. The results showed an increasing expression trend of EMT regulators in a panel of follicular tumour cases with a spectrum of morphological subtypes from low- to high-risk malignancy. The expression of EMT regulators was higher in the WI-FTC, PDTC and ATC groups but focal and lower in the FA and MI-FTC groups. Different expression intensity of E-CAD and EMT regulators at the tumour centre part and the invasive front (IF) was observed. The loss of E-CAD and expression of EMT regulators was significantly correlated with distant metastasis and vascular invasion (VI) in the well-differentiated follicular carcinoma (WD-FTC), and six tumours of metastatic sites also showed variables positive for EMT regulators. The disease-free survival analysis showed an apparent relationship between the expression of EMT regulators and the tumour disease-free outcomes in WD-FTC. CONCLUSIONS: Our study supported the role of EMT in the development of follicular thyroid carcinoma and indicated that EMT regulatory proteins may play an important role in WD-FTC that are widely invasive and exhibit distant metastasis.

Polarity protein Par3/Bazooka follows myosin-dependent junction repositioning.

The polarity protein Par3/Bazooka (Baz) has been established as a central component of the apical basal polarity system that determines the position of cell-cell junctions in epithelial cells. Consistent with that view, we show that shortly before gastrulation in Drosophila, Baz protein in the mesoderm is down-regulated from junctional sites in response to Snail (Sna) expression. This down-regulation leads to a specific decrease in adherens junctions without affecting other E-Cadherin pools. However, we further show that, interactions between Baz and junctions are not unidirectional. During apical constriction and the internalization of the mesoderm, down-regulation of Baz is transiently blocked as adherens junctions shift apically and are strengthened in response to tension generated by contractile actomyosin. When such junction remodeling is prevented by down-regulating myosin, Baz is lost prematurely in mesodermal epithelium. During such apical shifts, Baz is initially left behind as the junction shifts position, but then re-accumulates at the new location of the junctions. On the dorsal side of the embryo, a similar pattern of myosin activity appears to limit the basal shift in junctions normally driven by Baz that controls epithelium folding. Our results suggest a model where the sensitivity of Baz to Sna expression leads to the Sna-dependent junction disassembly required for a complete epithelium-mesenchymal transition. Meanwhile this loss of Baz-dependent junction maintenance is countered by the myosin-based mechanism which promotes an apical shift and strengthening of junctions accompanied by a transient re-positioning and maintenance of Baz proteins.

Beta2-adrenergic signaling affects the phenotype of human cardiac progenitor cells through EMT modulation.

Human cardiac progenitor cells (CPCs) offer great promises to cardiac cell therapy for heart failure. Many in vivo studies have shown their therapeutic benefits, paving the way for clinical translation. The 3D model of cardiospheres (CSs) represents a unique niche-like in vitro microenvironment, which includes CPCs and supporting cells. CSs have been shown to form through a process mediated by epithelial-to-mesenchymal transition (EMT). ß2-Adrenergic signaling significantly affects stem/progenitor cells activation and mobilization in multiple tissues, and crosstalk between ß2-adrenergic signaling and EMT processes has been reported. In the present study, we aimed at investigating the biological response of CSs to ß2-adrenergic stimuli, focusing on EMT modulation in the 3D culture system of CSs. We treated human CSs and CS-derived cells (CDCs) with the ß2-blocker butoxamine (BUT), using either untreated or ß2 agonist (clenbuterol) treated CDCs as control. BUT-treated CS-forming cells displayed increased migration capacity and a significant increase in their CS-forming ability, consistently associated with increased expression of EMT-related genes, such as Snai1. Moreover, long-term BUT-treated CDCs contained a lower percentage of CD90+ cells, and this feature has been previously correlated with higher cardiogenic and therapeutic potential of the CDCs population. In addition, long-term BUT-treated CDCs had an increased ratio of collagen-III/collagen-I gene expression levels, and showed decreased release of inflammatory cytokines, overall supporting a less fibrosis-prone phenotype. In conclusion, ß2 adrenergic receptor block positively affected the stemness vs commitment balance within CSs through the modulation of type1-EMT (so called "developmental"). These results further highlight type-1 EMT to be a key process affecting the features of resident cardiac progenitor cells, and mediating their response to the microenvironment.

[Inhibition of Histone Deacetylases Reverses Epithelial-Mesenchymal Transition in Triple-Negative Breast Cancer Cells through a Slug Mediated Mechanism].

High metastatic ability and poor clinical outcome are the most known clinical features of the triple-negative breast tumors. Given that the tumor cells undergoing epithelial-mesenchymal transition (EMT) often gain malignant and invasive features, we have investigated the possibility of EMT reversal in triple-negative breast cancer cells by targeting the epigenetic-modifying enzymatic complexes named histone deacetylases (HDACs) and examined the possible mechanism underlying the HDACs-based inversion in model MDA-MB-231 cells. Cells were treated with a maximal tolerable 200 nM concentrations of classical HDACs inhibitor Trichostatin A (TSA) for 48 h and afterwards the invasiveness and immigration of the cells were evaluated in TransWell Invasion Scratch Wound Healing assays. Then, in treated and control cells, quantitative real time-PCR reacions were performed for assessing the gene expression of EMT biomarkers E-cadherin, Vimentin and transcriptional factor Slug. After TSA treatment, the invasion and migration properties MDA-MB-231 cells significantly decreased, gene expression of E-cadherin was significantly up-regulated, while the levels of Slug and Vimentin encoding mRNAs were suppressed. We conclude that inhibition of HDACs in triple-negative breast cancer cells may lead to inversion of EMT and the decrease of invasiveness by down-regulating the gene expression of Slug. Since EMT is known as a pre-metastatic process, triple-negative breast tumors, the EMT reversal effects of HDACs inhibition may reduce tumor cell metastasis.

14-3-3σ Gene Loss Leads to Activation of the Epithelial to Mesenchymal Transition Due to the Stabilization of c-Jun Protein.

Loss of 14-3-3σ has been observed in multiple tumor types; however, the mechanisms by which 14-3-3σ loss leads to tumor progression are not understood. The experiments in this report demonstrate that loss of 14-3-3σ leads to a decrease in the expression of epithelial markers and an increase in the expression of mesenchymal markers, which is indicative of an induction of the epithelial to mesenchymal transition (EMT). The EMT was accompanied by an increase in migration and invasion in the 14-3-3σ(-/-) cells. 14-3-3σ(-/-) cells show increased stabilization of c-Jun, resulting in an increase in the expression of the EMT transcription factor slug. 14-3-3σ induces the ubiquitination and degradation of c-Jun in an FBW7-dependent manner. c-Jun ubiquitination is dependent on the presence of an intact nuclear export pathway as c-Jun is stabilized and localized to the nucleus in the presence of a nuclear export inhibitor. Furthermore, the absence of 14-3-3σ leads to the nuclear accumulation and stabilization of c-Jun, suggesting that 14-3-3σ regulates the subcellular localization of c-Jun. Our results have identified a novel mechanism by which 14-3-3σ maintains the epithelial phenotype by inhibiting EMT and suggest that this property of 14-3-3σ might contribute to its function as a tumor suppressor gene.

In Pulmonary Arterial Hypertension, Reduced BMPR2 Promotes Endothelial-to-Mesenchymal Transition via HMGA1 and Its Target Slug.

BACKGROUND: We previously reported high-throughput RNA sequencing analyses that identified heightened expression of the chromatin architectural factor High Mobility Group AT-hook 1 (HMGA1) in pulmonary arterial endothelial cells (PAECs) from patients who had idiopathic pulmonary arterial hypertension (PAH) in comparison with controls. Because HMGA1 promotes epithelial-to-mesenchymal transition in cancer, we hypothesized that increased HMGA1 could induce transition of PAECs to a smooth muscle (SM)-like mesenchymal phenotype (endothelial-to-mesenchymal transition), explaining both dysregulation of PAEC function and possible cellular contribution to the occlusive remodeling that characterizes advanced idiopathic PAH. METHODS AND RESULTS: We documented increased HMGA1 in PAECs cultured from idiopathic PAH versus donor control lungs. Confocal microscopy of lung explants localized the increase in HMGA1 consistently to pulmonary arterial endothelium, and identified many cells double-positive for HMGA1 and SM22α in occlusive and plexogenic lesions. Because decreased expression and function of bone morphogenetic protein receptor 2 (BMPR2) is observed in PAH, we reduced BMPR2 by small interfering RNA in control PAECs and documented an increase in HMGA1 protein. Consistent with transition of PAECs by HMGA1, we detected reduced platelet endothelial cell adhesion molecule 1 (CD31) and increased endothelial-to-mesenchymal transition markers, αSM actin, SM22α, calponin, phospho-vimentin, and Slug. The transition was associated with spindle SM-like morphology, and the increase in αSM actin was largely reversed by joint knockdown of BMPR2 and HMGA1 or Slug. Pulmonary endothelial cells from mice with endothelial cell-specific loss of Bmpr2 showed similar gene and protein changes. CONCLUSIONS: Increased HMGA1 in PAECs resulting from dysfunctional BMPR2 signaling can transition endothelium to SM-like cells associated with PAH.

Vasohibin-2 is required for epithelial-mesenchymal transition of ovarian cancer cells by modulating transforming growth factor-ß signaling.

Vasohibin-2 (VASH2) is a homolog of VASH1, an endothelium-derived angiogenesis inhibitor. Vasohibin-2 is mainly expressed in cancer cells, and has been implicated in the progression of cancer by inducing angiogenesis and tumor growth. Although VASH2 has been recently reported to be involved in epithelial-mesenchymal transition (EMT), its precise roles are obscure. The aim of the present study was to clarify the role of VASH2 in the EMT of cancer cells in relation to transforming growth factor-ß (TGF-ß) signaling, which is a major stimulator of EMT. Decreased expression of VASH2 in ovarian cancer cells significantly repressed the expression of TGF-ß type I receptor, namely activin receptor-like kinase 5. Transforming growth factor-ß1-induced phosphorylation of Smad2 and Smad3 was markedly decreased in VASH2 knockdown cells while the expression of Smad2 and Smad3 was unchanged. Accordingly, the responses to TGF-ß1 shown by promoter assay and plasminogen activator inhibitor type 1 expression were significantly attenuated in VASH2 knockdown cells. Furthermore, knockdown of VASH2 in cancer cells abrogated the TGF-ß1-induced reduced expression of epithelial markers including E-cadherin, and the elevated expression of mesenchymal markers including fibronectin, ZEB2, and Snail2, suggesting that endogenous VASH2 is required for TGF-ß1-induced EMT. In accordance with these results, the effects of TGF-ß1 on cell morphology, migration, invasion, and MMP2 expression were also abrogated when VASH2 was knocked down. These results indicate that VASH2 played a significant role in the EMT by modulating the TGF-ß signaling. We propose that VASH2 would be a novel molecular target for the prevention of EMT in cancers.

SLUG transcription factor: a pro-survival and prognostic factor in gastrointestinal stromal tumour.

BACKGROUND: The SLUG transcription factor has been linked with the KIT signalling pathway that is important for gastrointestinal stromal tumour (GIST) tumourigenesis. Its clinical significance in GIST is unknown. METHODS: Influence of SLUG expression on cell proliferation and viability were investigated in GIST48 and GIST882 cell lines. The association between tumour SLUG expression in immunohistochemistry and recurrence-free survival (RFS) was studied in two clinical GIST series, one with 187 patients treated with surgery alone, and another one with 313 patients treated with surgery and adjuvant imatinib. RESULTS: SLUG downregulation inhibited cell proliferation, induced cell death in both cell lines, and sensitised GIST882 cells to lower imatinib concentrations. SLUG was expressed in 125 (25.0%) of the 500 clinical GISTs evaluated, and expression was associated with several factors linked with unfavourable prognosis. SLUG expression was associated with unfavourable RFS both when patients were treated with surgery alone (HR=3.40, 95% CI=1.67-6.89, P=0.001) and when treated with surgery plus adjuvant imatinib (HR=1.83, 95% CI=1.29-2.60, P=0.001). CONCLUSIONS: GIST patients with high tumour SLUG expression have unfavourable RFS. SLUG may mediate pro-survival signalling in GISTs.

Targeting ID2 expression triggers a more differentiated phenotype and reduces aggressiveness in human salivary gland cancer cells.

Inhibitors of DNA-binding (ID) proteins are negative regulators of basic helix-loop-helix transcription factors and generally stimulate cell proliferation and inhibit differentiation. We previously determined that ID1 was highly expressed in aggressive salivary gland cancer (SGC) cells in culture. Here, we show that ID2 is also expressed in aggressive SGC cells. ID2 knockdown triggers important changes in cell behavior, that is, it significantly reduces the expression of N-cadherin, vimentin and Snail, induces E-cadherin expression and leads to a more differentiated phenotype exemplified by changes in cell shape. Moreover, ID2 knockdown almost completely suppresses invasion and the expression of matrix metalloproteinase 9. In conclusion, ID2 expression maintains an aggressive phenotype in SGC cells, and ID2 repression triggers a reduction in cell aggressiveness. ID2 therefore represents a potential therapeutic target during SGC progression. ID proteins are negative regulators of basic helix-loop-helix transcription factors and generally stimulate cell proliferation and inhibit differentiation. ID2 knockdown triggers important changes in cell behavior, that is, it significantly reduces the expression of N-cadherin, vimentin and Snail, induces E-cadherin expression and leads to a more differentiated phenotype exemplified by changes in cell shape. ID2 therefore represents a potential therapeutic target during SGC progression.

Cancer-associated fibroblasts secrete FGF-1 to promote ovarian proliferation, migration, and invasion through the activation of FGF-1/FGFR4 signaling.

Ovarian cancer is the most lethal gynecologic malignancy, due to its high propensity for metastasis. Cancer-associated fibroblasts, as the dominant component of tumor microenvironment, are crucial for tumor progression. However, the mechanisms underlying the regulation of ovarian cancer cells by cancer-associated fibroblasts remain little known. Here, we first isolated cancer-associated fibroblasts from patients' ovarian tissues and found that cancer-associated fibroblasts promoted SKOV3 cells' proliferation, migration, and invasion. Fibroblast growth factor-1 was identified as a highly increased factor in cancer-associated fibroblasts compared with normal fibroblasts by quantitative reverse transcription polymerase chain reaction (~4.6-fold, p < 0.01) and ELISA assays (~4-fold, p < 0.01). High expression of fibroblast growth factor-1 in cancer-associated fibroblasts either naturally or through gene recombination led to phosphorylation of fibroblast growth factor receptor 4 in SKOV3 cells, which is followed by the activation of mitogen-activated protein kinase/extracellular signal-regulated protein kinase pathway and epithelial-to-mesenchymal transition-associated gene Snail1 and MMP3 expression. Moreover, treatment of SKOV3 cell with fibroblast growth factor receptor inhibitor PD173074 terminated cellular proliferation, migration, and invasion, reduced the phosphorylation level of fibroblast growth factor receptor 4, and suppressed the activation of mitogen-activated protein kinase/extracellular signal-regulated protein kinase pathway. In addition, the expression level of Snail1 and MMP3 was reduced, while the expression level of E-cadherin increased. These observations suggest a crucial role for cancer-associated fibroblasts and fibroblast growth factor-1/fibroblast growth factor receptor 4 signaling in the progression of ovarian cancer. Therefore, this fibroblast growth factor-1/fibroblast growth factor receptor 4 axis may become a potential target for the treatment of ovarian cancer.

Alex3 suppresses non-small cell lung cancer invasion via AKT/Slug/E-cadherin pathway.

Alex3, is a newly identified mitochondrial protein, regulates mitochondrial dynamics and is involved in neural development. However, its expression pattern and clinicopathological relevance in human tumors are still unclear. In this study, Immunohistochemistry assay was performed in 109 cases of lung cancer samples and found that Alex 3 expression in lung cancer tissues was significantly lower than adjacent normal lung tissues (28.4% vs 52.6%, p < 0.001). Sequent statistical analysis indicated that negative Alex3 expression was significantly associated with advanced tumor-node-metastasis stages (p = 0.001), positive lymph node metastasis (p = 0.005), and poor prognosis (p = 0.008). After overexpression of Alex3, levels of p-AKT and Slug were downregulated, while level of E-cadherin was upregulated, which results in the inhibition of invasion and migration ability of lung cancer cells. In conclusion, reduction of Alex3 correlates with the development of non-small cell lung cancer and predicts adverse clinical outcome of non-small cell lung cancer patients. The effect of Alex3 on inhibiting invasion and migration may attribute to upregulation of E-cadherin expression through AKT-Slug pathway inactivation.

HR+HER2- breast cancers with growth factor receptor-mediated EMT have a poor prognosis and lapatinib downregulates EMT in MCF-7 cells.

Despite an overall good prognosis, a significant proportion of patients with hormone receptor positive human epidermal growth factor receptor 2 negative breast cancers develop distant metastases. The metastatic potential of epithelial cells is known to be regulated by tumor-stromal interaction and mediated by epithelial-to-mesenchymal transition. Hormone receptor positive human epidermal growth factor receptor 2 negative tumors were used to estimate markers of epithelial-to-mesenchymal transition, and the luminal breast cancer cell line MCF-7 was used to examine the interactions between integrins and growth factor receptors in causation of epithelial-to-mesenchymal transition. A total of 140 primary tumors were sub-divided into groups enriched for the markers of epithelial-to-mesenchymal transition (snail family transcriptional repressor 2 and integrin ß6) versus those with low levels. Within the epithelial-to-mesenchymal transition+ tumors, there was a positive correlation between the transcripts of integrin ß6 and growth factor receptors-human epidermal growth factor receptor 2 and epidermal growth factor receptor. In tumors enriched for epithelial-to-mesenchymal transition markers, patients with tumors with the highest quartile of growth factor receptor transcripts had a shorter disease-free survival compared to patients with low growth factor receptor expression by Kaplan-Meier analysis (log rank, p = 0.03). Epithelial-to-mesenchymal transition was induced in MCF-7 cells by treatment with transforming growth factor beta 1 and confirmed by upregulation of SNAI1 and SNAI2 transcripts, increase of vimentin and integrin ß6 protein, and repression of E-cadherin. Treatment of these cells with the dual-specificity tyrosine-kinase inhibitor lapatinib led to downregulation of epithelial-to-mesenchymal transition as indicated by lower levels of SNAI1 and SNAI2 transcripts, integrin αvß6, and matrix metalloproteinase 9 protein. The results suggest that synergistic interactions between growth factor receptors and integrin ß6 could mediate epithelial-to-mesenchymal transition and migration in a subset of luminal breast cancers and lapatinib might be effective in disrupting this interaction.

Directed Dedifferentiation Using Partial Reprogramming Induces Invasive Phenotype in Melanoma Cells.

The combination of cancer-focused studies and research related to nuclear reprogramming has gained increasing importance since both processes-reprogramming towards pluripotency and malignant transformation-share essential features. Studies have revealed that incomplete reprogramming of somatic cells leads to malignant transformation indicating that epigenetic regulation associated with iPSC generation can drive cancer development [J Mol Cell Biol 2011;341-350; Cell 2012;151:1617-1632; Cell 2014;156:663-677]. However, so far it is unclear whether incomplete reprogramming also affects cancer cells and their function. In the context of melanoma, dedifferentiation correlates to therapy resistance in mouse studies and has been documented in melanoma patients [Nature 2012;490:412-416; Clin Cancer Res 2014;20:2498-2499]. Therefore, we sought to investigate directed dedifferentiation using incomplete reprogramming of melanoma cells. Using a murine model we investigated the effects of partial reprogramming on the cellular plasticity of melanoma cells. We demonstrate for the first time that induced partial reprogramming results in a reversible phenotype switch in melanoma cells. Partially reprogrammed cells at day 12 after transgene induction display elevated invasive potential in vitro and increased lung colonization in vivo. Additionally, using global gene expression analysis of partially reprogrammed cells, we identified SNAI3 as a novel invasion-related marker in human melanoma. SNAI3 expression correlates with tumor thickness in primary melanomas and thus, may be of prognostic value. In summary, we show that investigating intermediate states during the process of reprogramming melanoma cells can reveal novel insights into the pathogenesis of melanoma progression. We propose that deeper analysis of partially reprogrammed melanoma cells may contribute to identification of yet unknown signaling pathways that can drive melanoma progression.