Downregulation of MMP-9 in ERK-mutated stable transfectants inhibits glioma invasion in vitro

The tumor-associated fibrotic reactions in microenvironment aggravate glioma chemoresistance

Malignant gliomas are one of the most common and lethal brain tumors with poor prognosis. Most patients with glioblastoma (GBM) die within 2 years of diagnosis, even after receiving standard treatments including surgery combined with concomitant radiotherapy and chemotherapy. Temozolomide (TMZ) is the first-line chemotherapeutic agent for gliomas, but the frequent acquisition of chemoresistance generally leads to its treatment failure. Thus, it's urgent to investigate the strategies for overcoming glioma chemoresistance. Currently, many studies have elucidated that cancer chemoresistance is not only associated with the high expression of drug-resistance genes in glioma cells but also can be induced by the alterations of the tumor microenvironment (TME). Numerous studies have explored the use of antifibrosis drugs to sensitize chemotherapy in solid tumors, and surprisingly, these preclinical and clinical attempts have exhibited promising efficacy in treating certain types of cancer. However, it remains unclear how tumor-associated fibrotic alterations in the glioma microenvironment (GME) mediate chemoresistance. Furthermore, the possible mechanisms behind this phenomenon are yet to be determined. In this review, we have summarized the molecular mechanisms by which tumor-associated fibrotic reactions drive glioma transformation from a chemosensitive to a chemoresistant state. Additionally, we have outlined antitumor drugs with antifibrosis functions, suggesting that antifibrosis strategies may be effective in overcoming glioma chemoresistance through TME normalization.

FMRP modulates the Wnt signalling pathway in glioblastoma

Converging evidence indicates that the Fragile X Messenger Ribonucleoprotein (FMRP), which absent or mutated in Fragile X Syndrome (FXS), plays a role in many types of cancers. However, while FMRP roles in brain development and function have been extensively studied, its involvement in the biology of brain tumors remains largely unexplored. Here we show, in human glioblastoma (GBM) biopsies, that increased expression of FMRP directly correlates with a worse patient outcome. In contrast, reductions in FMRP correlate with a diminished tumor growth and proliferation of human GBM stem-like cells (GSCs) in vitro in a cell culture model and in vivo in mouse brain GSC xenografts. Consistently, increased FMRP levels promote GSC proliferation. To characterize the mechanism(s) by which FMRP regulates GSC proliferation, we performed GSC transcriptome analyses in GSCs expressing high levels of FMRP, and in these GSCs after knockdown of FMRP. We show that the WNT signalling is the most significantly enriched among the published FMRP target genes and genes involved in ASD. Consistently, we find that reductions in FMRP downregulate both the canonical WNT/β-Catenin and the non-canonical WNT-ERK1/2 signalling pathways, reducing the stability of several key transcription factors (i.e. β-Catenin, CREB and ETS1) previously implicated in the modulation of malignant features of glioma cells. Our findings support a key role for FMRP in GBM cancer progression, acting via regulation of WNT signalling.

Tumor suppressor p53 restrains cancer cell dissemination by modulating mitochondrial dynamics

Tumor suppressor p53 plays a central role in preventing tumorigenesis. Here, we unravel how p53 modulates mitochondrial dynamics to restrain the metastatic properties of cancer cells. p53 inhibits the mammalian target of rapamycin complex 1 (mTORC1) signaling to attenuate the protein level of mitochondrial fission process 1 (MTFP1), which fosters the pro-fission dynamin-related protein 1 (Drp1) phosphorylation. This regulatory mechanism allows p53 to restrict cell migration and invasion governed by Drp1-mediated mitochondrial fission. Downregulating p53 expression or elevating the molecular signature of mitochondrial fission correlates with aggressive tumor phenotypes and poor prognosis in cancer patients. Upon p53 loss, exaggerated mitochondrial fragmentation stimulates the activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling resulting in epithelial-to-mesenchymal transition (EMT)-like changes in cell morphology, accompanied by accelerated matrix metalloproteinase 9 (MMP9) expression and invasive cell migration. Notably, blocking the activation of mTORC1/MTFP1/Drp1/ERK1/2 axis completely abolishes the p53 deficiency-driven cellular morphological switch, MMP9 expression, and cancer cell dissemination. Our findings unveil a hitherto unrecognized mitochondria-dependent molecular mechanism underlying the metastatic phenotypes of p53-compromised cancers.

Citromycin Isolated from the Antarctic Marine-Derived Fungi, Sporothrix sp., Inhibits Ovarian Cancer Cell Invasion via Suppression of ERK Signaling

Recently, microorganisms and their metabolites in the Antarctic marine environment have attracted attention as useful sources for novel therapeutics, including anticancer drugs. Here, we investigated the effects of citromycin, isolated from the Antarctic marine-derived fungus, Sporothrix sp., on human ovarian cancer cells. Citromycin inhibited the migration and invasion of human ovarian cancer SKOV3 and A2780 cells, but had no cytotoxic activity against them. Additionally, it inhibited the expression of epithelial–mesenchymal transition (EMT) markers and the activation of matrix metalloproteinase (MMP)-2 and MMP9. Moreover, extracellular signal-regulated kinase (ERK)-1/2 signaling was inhibited after citromycin treatment, and the ectopic expression of ERK negated the anti-invasive activity of citromycin. Our findings suggest that citromycin inhibits the migration and invasion of human ovarian cancer cells by downregulating the expression levels of EMT markers and MMP-2/9 via inhibition of the ERK1/2 pathway.

MMP9: A Tough Target for Targeted Therapy for Cancer

Having the capability to proteolyze diverse structural and signaling proteins, matrix metalloproteinase 9 (MMP9), one of the best-studied secretory endopeptidases, has been identified as a crucial mediator of processes closely associated with tumorigenesis, such as the extracellular matrix reorganization, epithelial to mesenchymal transition, cell migration, new blood vessel formation, and immune response. In this review, we present the current state of knowledge on MMP9 and its role in cancer growth in the context of cell adhesion/migration, cancer-related inflammation, and tumor microenvironment formation. We also summarize recent achievements in the development of selective MMP9 inhibitors and the limitations of using them as anticancer drugs.

The Metalloprotease-Disintegrin ADAM8 Alters the Tumor Suppressor miR-181a-5p Expression Profile in Glioblastoma Thereby Contributing to Its Aggressiveness

Glioblastoma (GBM) as the most common and aggressive brain tumor is characterized by genetic heterogeneity, invasiveness, radio-/chemoresistance, and occurrence of GBM stem-like cells. The metalloprotease-disintegrin ADAM8 is highly expressed in GBM tumor and immune cells and correlates with poor survival. In GBM, ADAM8 affects intracellular kinase signaling and increases expression levels of osteopontin/SPP1 and matrix metalloproteinase 9 (MMP9) by an unknown mechanism. Here we explored whether microRNA (miRNA) expression levels could be regulators of MMP9 expression in GBM cells expressing ADAM8. Initially, we identified several miRNAs as dysregulated in ADAM8-deficient U87 GBM cells. Among these, the tumor suppressor miR-181a-5p was significantly upregulated in ADAM8 knockout clones. By inhibiting kinase signaling, we found that ADAM8 downregulates expression of miR-181a-5p via activation of signal transducer and activator of transcription 3 (STAT3) and mitogen-activated protein kinase (MAPK) signaling suggesting an ADAM8-dependent silencing of miR-181a-5p. In turn, mimic miR-181a-5p transfection caused decreased cell proliferation and lower MMP9 expression in GBM cells. Furthermore, miR-181a-5p was detected in GBM cell-derived extracellular vesicles (EVs) as well as patient serum-derived EVs. We identified miR-181a-5p downregulating MMP9 expression via targeting the MAPK pathway. Analysis of patient tissue samples (n=22) revealed that in GBM, miR-181a-5p is strongly downregulated compared to ADAM8 and MMP9 mRNA expression, even in localized tumor areas. Taken together, we provide evidence for a functional axis involving ADAM8/miR-181a-5p/MAPK/MMP9 in GBM tumor cells.

SIX1 transcription factor: A review of cellular functions and regulatory dynamics

Sine Oculis Homeobox 1 (SIX1) is a member of homeobox transcription factor family having pivotal roles in organismal development and differentiation. This protein functionally acts to regulate the expression of different proteins that are involved in organ development during embryogenesis and in disorders like cancer. Aberrant expression of this homeoprotein has therefore been reported in multiple pathological complexities like hearing impairment and renal anomalies during development and tumorigenesis in adult life. Most of the cellular effects mediated by it are mostly due to its role as a transcription factor. This review presents a concise narrative of its structure, interaction partners and cellular functions vis a vis its role in cancer. We thoroughly discuss the reported molecular mechanisms that govern its function in cellular milieu. Its post-translational regulation by phosphorylation and ubiquitination are also discussed with an emphasis on yet to be explored mechanistic insights regulating its molecular dynamics to fully comprehend its role in development and disease.

Tumor-Associated Microglia and Macrophages in the Glioblastoma Microenvironment and Their Implications for Therapy

Glioblastoma is the most frequent and malignant primary brain tumor. Standard of care includes surgery followed by radiation and temozolomide chemotherapy. Despite treatment, patients have a poor prognosis with a median survival of less than 15 months. The poor prognosis is associated with an increased abundance of tumor-associated microglia and macrophages (TAMs), which are known to play a role in creating a pro-tumorigenic environment and aiding tumor progression. Most treatment strategies are directed against glioblastoma cells; however, accumulating evidence suggests targeting of TAMs as a promising therapeutic strategy. While TAMs are typically dichotomously classified as M1 and M2 phenotypes, recent studies utilizing single cell technologies have identified expression pattern differences, which is beginning to give a deeper understanding of the heterogeneous subpopulations of TAMs in glioblastomas. In this review, we evaluate the role of TAMs in the glioblastoma microenvironment and discuss how their interactions with cancer cells have an extensive impact on glioblastoma progression and treatment resistance. Finally, we summarize the effects and challenges of therapeutic strategies, which specifically aim to target TAMs.

Cyclin G2 Inhibits Oral Squamous Cell Carcinoma Growth and Metastasis by Binding to IGFBP3 and Regulating the FAK-SRC-STAT Signaling Pathway

The cell cycle protein cyclin G2 is considered a tumor suppressor. However, its regulatory effects and potential mechanisms in oral cancers are not well understood. This study aimed to investigate the effect of cyclin G2 on oral squamous cell carcinoma (OSCC). The data from 80 patients with OSCC were utilized to predict the abnormal expression of cyclin G2. The proliferation and metastasis were determined by a cell counting Kit-8 assay, flow cytometry, a wound-healing assay, and a cell invasion assay. The expression of key proteins and genes associated with the cyclin G2 signaling pathways was determined by western blotting and real-time PCR, respectively. The orthotopic nude mice model was established by a mouth injection of SCC9 cells overexpressing cyclin G2. We showed that the low level of cyclin G2 in OSCC, which is negatively correlated with clinical staging, was a negative prognostic factor for the disease. We also found that cyclin G2 inhibited the proliferation, metastasis, and blocked the cell cycle at G1/S of OSCC cells, suggesting that cyclin G2 has an inhibitory effect in OSCC. Mechanistically, cyclin G2 inhibited the growth and metastasis of OSCC by binding to insulin-like growth factor binding protein 3 (IGFBP3) and regulating the focal adhesion kinase (FAK) -SRC-STAT signal transduction pathway. Cyclin G2 competed with integrin to bind to IGFBP3; the binding between integrin and IGFBP3 was reduced after cyclin G2 overexpression, thereby inhibiting the phosphorylation of FAK and SRC. These results showed that cyclin G2 inhibited the progression of OSCC by interacting with IGFBP3 and that it may be a new target for OSCC treatment.

Mechanistic Understanding of Curcumin's Therapeutic Effects in Lung Cancer

Lung cancer is among the most common cancers with a high mortality rate worldwide. Despite the significant advances in diagnostic and therapeutic approaches, lung cancer prognoses and survival rates remain poor due to late diagnosis, drug resistance, and adverse effects. Therefore, new intervention therapies, such as the use of natural compounds with decreased toxicities, have been considered in lung cancer therapy. Curcumin, a natural occurring polyphenol derived from turmeric (Curcuma longa) has been studied extensively in recent years for its therapeutic effects. It has been shown that curcumin demonstrates anti-cancer effects in lung cancer through various mechanisms, including inhibition of cell proliferation, invasion, and metastasis, induction of apoptosis, epigenetic alterations, and regulation of microRNA expression. Several in vitro and in vivo studies have shown that these mechanisms are modulated by multiple molecular targets such as STAT3, EGFR, FOXO3a, TGF-β, eIF2α, COX-2, Bcl-2, PI3KAkt/mTOR, ROS, Fas/FasL, Cdc42, E-cadherin, MMPs, and adiponectin. In addition, limitations, strategies to overcome curcumin bioavailability, and potential side effects as well as clinical trials were also reviewed.

Zingerone suppresses angiogenesis via inhibition of matrix metalloproteinases during tumor development

Angiogenesis is an essential step for tumor survival and progression, and the inhibition of angiogenesis is a good strategy for tumor therapeutics. In this study, we investigated the therapeutic effect of zingerone in a mouse tumor model. Zingerone suppressed tumor progression and tumor angiogenesis. Moreover, we found that zingerone inhibited the angiogenic activities of endothelial cells by both direct and indirect means. A mechanistic study showed that the activities of MMP-2 and MMP-9 in tumor cells were decreased by treatment with zingerone. Interestingly, zingerone-mediated inhibition of MMP-2 and MMP-9 was involved in the JNK pathway. In conclusion, zingerone showed strong anti-angiogenic activity via the inhibition of MMP-2 and MMP-9 during tumor progression, suggesting that zingerone may be a potential therapeutic drug for human cancers.

Eya2 overexpression promotes the invasion of human astrocytoma through the regulation of ERK/MMP9 signaling

The overexpression of eyes absent (Eya) 2 has been found in several human cancers. However, its biological roles and clinical significance in human astrocytoma have not yet been explored. This study investigated the clinical significance and biological roles of Eya2 in human astrocytoma tissues and cell lines. Using immunohistochemistry, we found Eya2 overexpression in 33 out of 90 (36.7%) astrocytoma specimens. The rate of Eya2 overexpression was higher in grade III-IV (48.1%) than in grade Ⅰ+Ⅱ astrocytomas (21.1%). Transfection with an Eya2 expression plasmid was performed in A172 cells with a low endogenous expression of Eya2 and the knockdown of Eya2 was carried out in U251 cells with a high endogenous expression using siRNA. Eya2 overexpression induced A172 cell proliferation and invasion, while the knockdown of Eya2 using siRNA decreased the proliferation and invasion of U251 cells. In addition, we found that transfection with the Eya2 expression plasmid facilitated cell cycle progression, and that the knockdown of Eya2 inhibited cell cycle progression, accompanied by a change in the expression of cell cycle-related proteins, including cyclin D1 and cyclin E. Eya2 also positively regulated extracellular signal-regulated kinase (ERK) activity and matrix metalloproteinase (MMP)9 expression. The blockade of ERK signaling using an inhibitor abolished the effects of Eya2 on A172 cell invasion and MMP9 production. In addition, we found that there was a positive correlation between Eya2 and Six1 in the astrocytoma cell lines. Immunoprecipitation revealed that Eya2 interacted with Six1 protein in the U251 cell line, which exhibited a high expression of both proteins. Eya2 failed to upregulate MMP expression in the A172 cells in which Six1 was silenced. On the whole, our data indicate that Eya2 may serve as a potential oncoprotein in human astrocytoma. Eya2 regulates astrocytoma cell proliferation and invasion, possibly through the regulation of ERK signaling.

Six1 promotes colorectal cancer growth and metastasis by stimulating angiogenesis and recruiting tumor-associated macrophages

The homeoprotein Six1 is overexpressed in many human cancers and is associated with increased tumor progression and metastasis. Recent studies have shown that Six1 is associated with poorer overall survival in advanced-stage colorectal cancer (CRC). In the current study, we explored the functional changes and molecular events associated with Six1 overexpression in a mouse model of CRC. An orthotopic model and a splenic injection metastasis model were used to investigate the role of Six1 in CRC tumor growth and metastasis using mouse colon adenocarcinoma MC38 cells overexpressing Six1. We found that overexpression of Six1 dramatically promotes CRC tumor growth and metastasis in vivo. Six1 overexpression in MC38 increased protein levels of aldehyde dehydrogenase-1 and expanded CD44+/CD166+ populations, indicating Six1 increased features of cancer stem cells. In addition, Six1 overexpression stimulated angiogenesis by upregulating the expression of vascular endothelial growth factor (VEGF). Six1-overexpressing tumor cells recruited tumor-associated macrophages (TAM) by increasing the expression of macrophage-specific colony stimulating factor, chemokine (C-C motif) ligand 2/5 and VEGF, further facilitating CRC tumor growth and metastasis. Furthermore, we determined that Six1 activated mitogen-activated protein kinase (MAPK) signaling in CRC cells. In summary, our studies strongly suggest that Six1 overexpression promotes CRC growth and metastasis and remodels tumor stroma by stimulating angiogenesis and recruiting TAM. MAPK activation may be a pivotal event in Six1-associated tumor progression, which may provide opportunities for pharmacologic intervention.

M2-like macrophages induce colon cancer cell invasion via matrix metalloproteinases

The inflammatory milieu plays an important role in colon cancer development and progression. Previously, we have shown that tumor-associated macrophages (TAMs), an important component of the tumor microenvironment, are enriched in tumors compared with normal tissue and confer a poorer prognosis. In the present study, we found that matrix metallopeptidase-9 (MMP-9), which degrades extracellular matrix proteins, was increased in biopsies from colon cancer patients and in mouse xenografts with SW480 cell-derived tumors. SW480 colon cancer cells exposed to M2-like macrophage-conditioned medium (M2-medium) exhibited increased MMP-9 mRNA, protein expression and gelatinase activity. A similar effect was obtained by the addition of tumor necrosis factor-α (TNFα) and leukotriene D₄ (LTD₄ ). MMP-9 expression and activity were reduced by a TNFα blocking antibody adalimumab and a cysteinyl leukotriene receptor 1 (CysLTR1, the receptor for LTD₄ ) antagonist montelukast. M2-medium also induced changes in the epithelial-mesenchymal transition (EMT) markers E-cadherin, β-catenin, vimentin, and snail in SW480 cells. We also found that both M2-medium and TNFα and LTD₄ induced stabilization/nuclear translocation of β-catenin. Furthermore, we also observed an elongated phenotype that may indicate increased invasiveness, as confirmed in a collagen I invasion assay. M2-medium increased the invasive ability, and a similar effect was also obtained by the addition of TNFα and LTD₄ . The specific MMP inhibitor I or adalimumab and montelukast reduced the number of invasive cells. In conclusion, our findings show that M2-medium enriched in TNFα and LTD₄ promote colon cancer cell invasion via MMP-9 expression and activation and the induction of EMT.

HIV infection model of chronic obstructive pulmonary disease in mice

Cigarette smoke usage is prevalent in human immunodeficiency virus (HIV)-positive patients, and, despite highly active antiretroviral therapy, these individuals develop an accelerated form of chronic obstructive pulmonary disease (COPD). Studies investigating the mechanisms of COPD development in HIV have been limited by the lack of suitable mouse models. Here we describe a model of HIV-induced COPD in wild-type mice using EcoHIV, a chimeric HIV capable of establishing chronic infection in immunocompetent mice. A/J mice were infected with EcoHIV and subjected to whole body cigarette smoke exposure. EcoHIV was detected in alveolar macrophages of mice. Compared with uninfected mice, concomitant EcoHIV infection significantly reduced forced expiratory flow 50%/forced vital capacity and enhanced distal airspace enlargement following cigarette smoke exposure. Lung IL-6, granulocyte-macrophage colony-stimulating factor, neutrophil elastase, cathepsin G, and matrix metalloproteinase-9 expression was significantly enhanced in smoke-exposed EcoHIV-infected mice. These changes coincided with enhanced IκBα, ERK1/2, p38, and STAT3 phosphorylation and lung cell apoptosis. Thus, the EcoHIV smoke exposure mouse model reproduces several of the pathophysiological features of HIV-related COPD in humans, indicating that this murine model can be used to determine key parameters of HIV-related COPD and to test future therapies for this disorder.

Unraveling the Anticancer Effect of Curcumin and Resveratrol

Resveratrol and curcumin are natural products with important therapeutic properties useful to treat several human diseases, including cancer. In the last years, the number of studies describing the effect of both polyphenols against cancer has increased; however, the mechanism of action in all of those cases is not completely comprehended. The unspecific effect and the ability to interfere in assays by both polyphenols make this challenge even more difficult. Herein, we analyzed the anticancer activity of resveratrol and curcumin reported in the literature in the last 11 years, in order to unravel the molecular mechanism of action of both compounds. Molecular targets and cellular pathways will be described. Furthermore, we also discussed the ability of these natural products act as chemopreventive and its use in association with other anticancer drugs.

Sequestration of Vascular Endothelial Growth Factor (VEGF) Induces Late Restrictive Lung Disease

Rationale

Neonatal respiratory distress syndrome is a restrictive lung disease characterized by surfactant deficiency. Decreased vascular endothelial growth factor (VEGF), which demonstrates important roles in angiogenesis and vasculogenesis, has been implicated in the pathogenesis of restrictive lung diseases. Current animal models investigating VEGF in the etiology and outcomes of RDS require premature delivery, hypoxia, anatomically or temporally limited inhibition, or other supplemental interventions. Consequently, little is known about the isolated effects of chronic VEGF inhibition, started at birth, on subsequent developing lung structure and function.

Objectives

To determine whether inducible, mesenchyme-specific VEGF inhibition in the neonatal mouse lung results in long-term modulation of AECII and whole lung function.

Methods

Triple transgenic mice expressing the soluble VEGF receptor sFlt-1 specifically in the mesenchyme (Dermo-1/rtTA/sFlt-1) were generated and compared to littermate controls at 3 months to determine the impact of neonatal downregulation of mesenchymal VEGF expression on lung structure, cell composition and function. Reduced tissue VEGF bioavailability has previously been demonstrated with this model.

Measurements and Main Results

Triple transgenic mice demonstrated restrictive lung pathology. No differences in gross vascular development or protein levels of vascular endothelial markers was noted, but there was a significant decrease in perivascular smooth muscle and type I collagen. Mutants had decreased expression levels of surfactant protein C and hypoxia inducible factor 1-alpha without a difference in number of type II pneumocytes.

Conclusions

These data show that mesenchyme-specific inhibition of VEGF in neonatal mice results in late restrictive disease, making this transgenic mouse a novel model for future investigations on the consequences of neonatal RDS and potential interventions.

Magnolin inhibits cell migration and invasion by targeting the ERKs/RSK2 signaling pathway

BACKGROUND

Magnolin is a natural compound abundantly found in Magnolia flos, which has been traditionally used in oriental medicine to treat headaches, nasal congestion and anti-inflammatory reactions. Our recent results have demonstrated that magnolin targets the active pockets of ERK1 and ERK2, which are important signaling molecules in cancer cell metastasis. The aim of this study is to evaluate the effects of magnolin on cell migration and to further explore the molecular mechanisms involved.

METHODS

Magnolin-mediated signaling inhibition was confirmed by Western blotting using RSK2(+/+) and RSK2(-/-) MEFs, A549 and NCI-H1975 lung cancer cells, and by NF-κB and Cox-2 promoter luciferase reporter assays. Inhibition of cell migration by magnolin was examined by wound healing and/or Boyden Chamber assays using JB6 Cl41 and A549 human lung cancer cells. The molecular mechanisms involved in cell migration and epithelial-to-mesenchymal transition were determined by zymography, Western blotting, real-time PCR and immunocytofluorescence.

RESULTS

Magnolin inhibited NF-κB transactivation activity by suppressing the ERKs/RSK2 signaling pathway. Moreover, magnolin abrogated the increase in EGF-induced COX-2 protein levels and wound healing. In human lung cancer cells such as A549 and NCI-H1975, which harbor constitutive active Ras and EGFR mutants, respectively, magnolin suppressed wound healing and cell invasion as seen by a Boyden chamber assay. In addition, it was observed that magnolin inhibited MMP-2 and -9 gene expression and activity. The knockdown or knockout of RSK2 in A549 lung cancer cells or MEFs revealed that magnolin targeting ERKs/RSK2 signaling suppressed epithelial-to-mesenchymal transition by modulating EMT marker proteins such as N-cadherin, E-cadherin, Snail, Vimentin and MMPs.

CONCLUSIONS

These results demonstrate that magnolin inhibits cell migration and invasion by targeting the ERKs/RSK2 signaling pathway.

Inhibition of STAT3, FAK and Src mediated signaling reduces cancer stem cell load, tumorigenic potential and metastasis in breast cancer

Cancer stem cells (CSCs) are responsible for aggressive tumor growth, metastasis and therapy resistance. In this study, we evaluated the effects of Shikonin (Shk) on breast cancer and found its anti-CSC potential. Shk treatment decreased the expression of various epithelial to mesenchymal transition (EMT) and CSC associated markers. Kinase profiling array and western blot analysis indicated that Shk inhibits STAT3, FAK and Src activation. Inhibition of these signaling proteins using standard inhibitors revealed that STAT3 inhibition affected CSCs properties more significantly than FAK or Src inhibition. We observed a significant decrease in cell migration upon FAK and Src inhibition and decrease in invasion upon inhibition of STAT3, FAK and Src. Combined inhibition of STAT3 with Src or FAK reduced the mammosphere formation, migration and invasion more significantly than the individual inhibitions. These observations indicated that the anti-breast cancer properties of Shk are due to its potential to inhibit multiple signaling proteins. Shk also reduced the activation and expression of STAT3, FAK and Src in vivo and reduced tumorigenicity, growth and metastasis of 4T1 cells. Collectively, this study underscores the translational relevance of using a single inhibitor (Shk) for compromising multiple tumor-associated signaling pathways to check cancer metastasis and stem cell load.

Selective Allosteric Inhibition of MMP9 Is Efficacious in Preclinical Models of Ulcerative Colitis and Colorectal Cancer

Expression of matrix metalloproteinase 9 (MMP9) is elevated in a variety of inflammatory and oncology indications, including ulcerative colitis and colorectal cancer. MMP9 is a downstream effector and an upstream mediator of pathways involved in growth and inflammation, and has long been viewed as a promising therapeutic target. However, previous efforts to target matrix metalloproteinases (MMPs), including MMP9, have utilized broad-spectrum or semi-selective inhibitors. While some of these drugs showed signs of efficacy in patients, all MMP-targeted inhibitors have been hampered by dose-limiting toxicity or insufficient clinical benefit, likely due to their lack of specificity. Here, we show that selective inhibition of MMP9 did not induce musculoskeletal syndrome (a characteristic toxicity of pan-MMP inhibitors) in a rat model, but did reduce disease severity in a dextran sodium sulfate-induced mouse model of ulcerative colitis. We also found that MMP9 inhibition decreased tumor growth and metastases incidence in a surgical orthotopic xenograft model of colorectal carcinoma, and that inhibition of either tumor- or stroma-derived MMP9 was sufficient to reduce primary tumor growth. Collectively, these data suggest that selective MMP9 inhibition is a promising therapeutic strategy for treatment of inflammatory and oncology indications in which MMP9 is upregulated and is associated with disease pathology, such as ulcerative colitis and colorectal cancer. In addition, we report the development of a potent and highly selective allosteric MMP9 inhibitor, the humanized monoclonal antibody GS-5745, which can be used to evaluate the therapeutic potential of MMP9 inhibition in patients.

MEK/ERK pathway is positively involved in hypoxia-induced vasculogenic mimicry formation in hepatocellular carcinoma which is regulated negatively by protein kinase A

The aim of present investigation is to explore the molecular mechanisms of vasculogenic mimicry (VM) induced by hypoxia. Hepatocellular carcinoma cell lines were treated with CoCl2, and the VM-related parameters were assayed by real-time qPCR, Western blotting and immunofluorescence. Matrigel tube structure was also detected. We demonstrated that the expression of pMEK, MEK, pERK1/2 and ERK1/2 had a positive correlation with VM induced by hypoxia in MHCC97H while HepG2 signified VM under normoxia condition. PD98059 was negatively while epidermal growth factor positively participated in the increased tubes and area of VM. At the meaning time, the increased VM-related genes VE-cadherin, MMP2, MMP9, EphA2 and LAMC2 in hypoxia group were down-regulated by PD98059 in a dose-dependent manner. Furthermore, we elucidated that PKA, but not PKC, mediated the MEK/ERK pathway in a negative manner in VM. In conclusion, MEK/ERK pathway is positively involved in VM in hepatocellular carcinoma cell line, which was mediated by PKA negatively.

Systematic review of protein biomarkers of invasive behavior in glioblastoma

Glioblastoma (GBM) is an aggressive and incurable brain tumor with a grave prognosis. Recurrence is inevitable even with maximal surgical resection, in large part because GBM is a highly invasive tumor. Invasiveness also contributes to the failure of multiple cornerstones of GBM therapy, including radiotherapy, temozolomide chemotherapy, and vascular endothelial growth factor blockade. In recent years there has been significant progress in the identification of protein biomarkers of invasive phenotype in GBM. In this article, we comprehensively review the literature and survey a broad spectrum of biomarkers, including proteolytic enzymes, extracellular matrix proteins, cell adhesion molecules, neurodevelopmental factors, cell signaling and transcription factors, angiogenic effectors, metabolic proteins, membrane channels, and cytokines and chemokines. In light of the marked variation seen in outcomes in GBM patients, the systematic use of these biomarkers could be used to form a framework for better prediction, prognostication, and treatment selection, as well as the identification of molecular targets for further laboratory investigation and development of nascent, directed therapies.

Review: molecular mechanism of microglia stimulated glioblastoma invasion

Glioblastoma multiforme is one of the deadliest human cancers and is characterized by a high degree of microglia and macrophage infiltration. The role of these glioma infiltrating macrophages (GIMs) in disease progression has been the subject of recent investigation. While initially thought to reflect an immune response to the tumor, the balance of evidence clearly suggests GIMs can have potent tumor-tropic functions and assist in glioma cell growth and infiltration into normal brain. In this review, we focus on the evidence for GIMs aiding mediating glioblastoma motility and invasion. We survey the literature for molecular pathways that are involved in paracrine interaction between glioma cells and GIMs and assess which of these might serve as attractive targets for therapeutic intervention.

Stromal cell-derived factor-1 (SDF-1) enhances cells invasion by αvβ6 integrin-mediated signaling in ovarian cancer

Ovarian carcinoma is a common gynecological malignancy and a great threat to health as a result of metastasis. The chemokine stromal-derived factor (SDF-1) plays multiple roles in tumor pathogenesis. However, the precise molecular mechanism underlying SDF-1-induced ovarian cancer cell invasion is still undefined. αvβ6 integrin is an important factor in tumor progression. Therefore, we speculate that SDF-1-enhanced ovarian cancer cell invasion is related to αvβ6 integrin-mediated signaling. After culturing with SDF-1, an obvious time- and dose-dependent increase in αvβ6 integrin was demonstrated. Furthermore, CXC receptor 4 (CXCR4) was responsible for SDF-1-induced αvβ6 integrin expression. Simultaneously, SDF-1 was found to dramatically enhance extracellular matrix degradation via urokinase-type plasminogen activator (uPA) expression and cell invasion by αvβ6 integrin expression; these reinforce failed to be increased when pretreatment was performed with the CXCR4 inhibitor AMD3100 or anti-αvβ6 integrin antibody, respectively. In addition, αvβ6 integrin induced the phosphorylation of p38 MAPK and PI3 K/Akt, contributing to the up-regulation of uPA, as treatment with the specific inhibitor for p38 mitogen-activated protein kinases (MAPK) (SB203580) or phosphatidylinositol 3-kinase (PI3 K)/Akt (LY294002) strikingly abrogated uPA expression. Taken together, these results demonstrated that SDF-1 enhanced ovarian cancer cell invasion through αvβ6 integrin-mediated uPA expression via the p38 MAPK and PI3 K/Akt pathway. Consequently, our findings will provide a new explanation about how SDF-1 aggravates the pathogenesis of ovarian cancer.

2-Hydroxychalcone and xanthohumol inhibit invasion of triple negative breast cancer cells

Breast cancer is estimated as one of the most common causes of cancer death among women. In particular, triple negative breast cancers (TNBCs), which do not express the genes for estrogen/progesterone receptors (ER/PR) and human epidermal growth factor receptor 2 (HER2), have been associated with poor prognosis and metastasis. Chalcones, the biosynthetic precursors of flavonoids present in edible plants, exert cytotoxic and chemopreventive activities. Although mounting evidence suggests the anticancer properties of chalcones, limited information is available regarding the inhibitory effects of chalcones on the aggressiveness of breast cancer cells. The present study aimed to investigate the effects of chalcone and its derivatives on the growth and the invasiveness of TNBC cells. Here, we showed that treatment with chalcone, 2-hydroxychalcone, and xanthohumol for 24h inhibited the growth of MDA-MB-231 cells with IC50 values of 18.1, 4.6, and 6.7 μM, respectively. Similarly, Chalcone, 2-hydroxychalcone, and xanthohumol also exerted cytotoxicity in another TNBC cell line, Hs578T. Neohesperidin dihydrochalcone, 4-methoxychalcone, and hesperidin methylchalcone did not show the cytotoxicity on the MDA-MB-231 cells. Xanthohumol and 2-hydroxychalcone induced apoptosis by Bcl-2 downregulation. Importantly, 2-hydroxychalcone and xanthohumol exerted more potent inhibitory effects on the proliferation, MMP-9 expression and invasive phenotype of MDA-MB-231 than chalcone. These results suggest a potential application of these chalcones as anticancer agents that can alleviate malignant progression of TNBC.

Deltex-1 activates mitotic signaling and proliferation and increases the clonogenic and invasive potential of U373 and LN18 glioblastoma cells and correlates with patient survival

Glioblastoma (GBM) is a highly malignant primary tumor of the central nervous system originating in glial cells. GBM results in more years of life lost than any other cancer type. Low levels of Notch receptor expression correlates with prolonged survival in various high grade gliomas independent of other markers. Different downstream pathways of Notch receptors have been identified. We tested if the Notch/Deltex pathway, which is distinct from the canonical, CSL-mediated pathway, has a role in GBM. We show that the alternative or non-canonical Notch pathway functioning through Deltex1 (DTX1) mediates key features of glioblastoma cell aggressiveness. For example, DTX1 activates the RTK/PI3K/PKB and the MAPK/ERK mitotic pathways and induces anti-apoptotic Mcl-1. The clonogenic and growth potential of established glioma cells correlated with DTX1 levels. Microarray gene expression analysis further identified a DTX1-specific, MAML1-independent transcriptional program - including microRNA-21- which is functionally linked to the changes in tumor cell aggressiveness. Over-expression of DTX1 increased cell migration and invasion correlating to ERK activation, miR-21 levels and endogenous Notch levels. In contrast to high and intermediate expressors, patients with low DTX1 levels have a more favorable prognosis. The alternative Notch pathway via DTX1 appears to be an oncogenic factor in glioblastoma and these findings offer new potential therapeutic targets.

The ERK1/2 Inhibitor U0126 Attenuates Diabetes-Induced Upregulation of MMP-9 and Biomarkers of Inflammation in the Retina

This study was conducted to determine the expression of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in a time-dependent manner and the effect of extracellular-signal-regulated kinases-1/2 (ERK1/2) inhibition on the expressions of MMP-9, TIMP-1, and inflammatory biomarkers in the retinas of diabetic rats. The expression of MMP-9 was quantified by zymography, and the mRNA level of MMP-9 and TIMP-1 was quantified by RT-PCR. The expression of inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF- α ) was examined by Western blot analysis. MMP-9 expression was significantly higher in diabetic rat retinas compared to controls at all time points.TIMP-1 expression was nonsignificantly upregulated at 1week of diabetes and was significantly downregulated at 4 and 12 weeks of diabetes. Intravitreal administration of the ERK1/2 inhibitor U0126 prior to induction of diabetes decreased ERK1/2 activation, attenuated diabetes-induced upregulation of MMP-9, iNOS, IL-6, and TNF- α and upregulated TIMP-1 expression. In MMP-9 knockout mice, diabetes had no effect on retinal iNOS expression and its level remained unchanged. These data provide evidence that ERK1/2 signaling pathway is involved in MMP-9, iNOS, IL-6, and TNF- α induction in diabetic retinas and suggest that ERK1/2 can be a novel therapeutic target in diabetic retinopathy.

High levels of phosphorylated MAP kinase are associated with poor survival among patients with glioblastoma during the temozolomide era

We investigated whether high levels of activated mitogen-activated protein kinase (p-MAPK) were associated with poor survival among patients with newly diagnosed glioblastoma during the temozolomide era. Nuclear p-MAPK expression of 108 patients with GBM was quantified and categorized in the following levels: low (0%-10%), medium (11%-40%), and high (41%-100%). Independent predictors of overall survival were determined using a multivariate Cox proportional hazards model. Our study included 108 patients with newly diagnosed GBM. Median age was 65 years, and 74% had high Karnofsky performance status (KPS ≥ 80). Median overall survival among all patients was 19.5 months. Activated MAPK expression levels of <10%, 11%-40%, and ≥ 41% were observed in 33 (30.6%), 37 (34.3%), and 38 (35.2%) patients, respectively. Median survival for low, medium, and high p-MAPK expression was 32.4, 18.2, and 12.5 months, respectively. Multivariate analysis showed 2.4-times hazard of death among patients with intermediate p-MAPK than low p-MAPK expression (hazard ratio [HR], 2.4; P = .02); high-expression patients were 3.9 times more likely to die, compared with patients with low p-MAPK (HR, 3.9; P = .007). Patients aged ≥ 65 years (HR, 2.8; P = .002) with KPS < 80 (HR, 3.1; P = .0003) and biopsy or partial resection (HR, 1.9; P = .02) had higher hazard of death. MGMT and PTEN expression were not associated with survival differences. This study provides quantitative means of evaluating p-MAPK in patients with GBM. It confirms the significant and independent prognostic relevance of p-MAPK in predicting survival of patients with GBM treated in the temozolomide era and highlights the need for therapies targeting the p-MAPK oncogenic pathway.

Expression of pERK and pAKT in pediatric high grade astrocytomas: correlation with YKL40 and prognostic significance

The Ras signaling pathway, consisting of mitogen-activated protein kinase (MAPK) and PI3K/AKT signaling, is a prominent oncogenic pathways in adult diffuse gliomas, but few studies have evaluated such pathways in pediatric malignant gliomas. We investigated by immunohistochemistry MAPK and AKT signaling in a series of 28 pediatric high-grade gliomas (WHO grade III and IV). We sought a possible association of phospho-ERK (p-ERK) and phospho-AKT (p-AKT) with expression of other proteins involved in the Ras pathway, that is, YKL40, epidermal growth factor receptor (EGFR), EGFR vIII and c-Met. Moreover we correlated the expression of p-ERK and p-AKT with prognosis. No cases showed expression for c-Met and EGFR, and only one case was positive for EGFR vIII. YKL-40 protein was expressed in 43% of cases. We detected expression of p-ERK and p-AKT in 61% and 57%, respectively, of pediatric high grade gliomas. Statistical analysis comparing the two groups in term of high and low p-ERK and p-AKT expression showed a trend toward worse overall survival in patients with high expression of p-AKT. The activation of ERK and AKT suggest a possible role of this protein in inducing activation of the Ras signaling pathway in pediatric high-grade gliomas. Moreover high levels of p-AKT are associated with worse overall survival.

Ribosomal protein s3: a multifunctional target of attaching/effacing bacterial pathogens

The extraribosomal functions of ribosomal proteins have drawn significant recent attention. Ribosomal protein S3 (RPS3), a component of the eukaryotic 40S ribosomal subunit, is a multifunctional protein that regulates DNA repair, apoptosis, and the innate immune response to bacterial infection. Here we the review the latest findings about RPS3 extraribosomal functions, with special emphasis on their relation to microbial pathogenesis and enteropathogenic Escherichia coli.

Suppression of invasion and metastasis of prostate cancer cells by overexpression of NDRG2 gene

N-myc downstream regulated gene 2 (NDRG2) is involved in invasion and metastasis of cancer, furthermore it is frequently down-regulated in prostate cancer. Herein we evaluated the effect of NDRG2 overexpression on invasiveness and bone destruction in prostate cancer. The human prostate cancer cell line PC-3 and DU145 were infected with Ad-NDRG2 or Ad-LacZ. Overexpression of NDRG2 not only inhibited the growth of the cells, but also suppressed invasiveness of the cells in an in vitro assay. PC-3 cells infected with Ad-NDRG2 or Ad-LacZ were injected into the tibias of nude mice. Four weeks later, we found the mice injected with PC-3 cells overexpressing NDRG2 had smaller tumors and less bone destruction. These results demonstrate that NDRG2 overexpression can inhibit tumor growth and invasion, furthermore, it can decrease bone destruction caused by prostate cancer bone metastasis.

The pro-migratory and pro-invasive role of the procoagulant tissue factor in malignant gliomas

During the infiltration process, glioma cells are known to migrate along preexisting anatomical structures such as blood vessels, axonal fiber tracts and the subependymal space, thereby widely invading surrounding CNS tissue. This phenomenon represents a major obstacle for the clinical treatment of these tumours. Several extracellular key factors and intracellular signaling pathways have been previously linked to the highly aggressive, invasive phenotype observed in malignant gliomas. The glioblastoma (GBM) which is the most malignant form of these tumors, is histologically characterized by areas of tumor necroses and pseudopalisading cells, the latter likely representing tumor cells actively migrating away from the hypoxic-ischemic core of the tumor. It is believed that intravascular thromboses play a major role in the emergence of hypoxia and intratumoral necroses in GBMs. One of the most highly upregulated prothrombotic factor in malignant gliomas is tissue factor (TF), a 47 kDa type I transmembrane protein belonging to the cytokine receptor superfamily. In a recent study, we provided evidence that TF/FVIIa signaling via the protease-activated receptor 2 (PAR-2) promotes cell growth, migration and invasion of glioma cells. In this point of view article we outline the key molecular players involved in migration and invasion of gliomas, highlight the potential role of TF for the pro-migratory and pro-invasive phenotype of these tumors and discuss the underlying mechanisms on the cellular level and in the tumor microenvironment.

Overexpression of MMP-9 contributes to invasiveness of prostate cancer cell line LNCaP

Matrix metallaprotinase-9 (MMP-9) is zinc-containing proteinase whose expression and trafficking are frequently altered in cancer. MMP-9 in the plasma membrane and the secreted forms are thought to contribute to the invasive and metastatic properties of malignant tumors. We have manipulated the expression of MMP-9 in prostate tumor cell line LNCaP and measured their capacity to invade through a basement membrane matrix. Stable expression of human MMP-9 in a poorly metastatic LNCaP prostate cancer cell line produced a 2-3-fold increase in MMP-9 activity and a comparable increase in invasiveness. Transient transfection of LNCaP stable clone expressing MMP-9 with MMP-9 antisense oligonucleotide (ASODN) produced 55-90% less MMP-9 than control cells and were proportionately less invasive. In contrast, manipulating MMP-9 levels had no effect on cell migration across an uncoated membrane. A standard MMP-9 inhibitor at a concentration ranging from 1-10 nM, caused a nearly quantitative inhibition of extracellular MMP-9 activity and had significant effect on basement membrane invasion. Collectively, these results confirm the role of MMP-9 in tissue remodeling associated with prostate tumor invasion.

Collagen I induces discoidin domain receptor (DDR) 1 expression through DDR2 and a JAK2-ERK1/2-mediated mechanism in primary human lung fibroblasts

Discoidin domain receptors (DDRs) DDR1 and DDR2 are receptor tyrosine kinases with the unique ability among receptor tyrosine kinases to respond to collagen. Several signaling molecules have been implicated in DDR signaling, including Shp-2, Src, and MAPK pathways, but a detailed understanding of these pathways and their transcriptional targets is still lacking. Similarly, the regulation of the expression of DDRs is poorly characterized with only a few inflammatory mediators, such as lipopolysaccharide and interleukin-1β identified as playing a role in DDR1 expression. DDRs have been reported to induce the expression of various genes including matrix metalloproteinases and bone morphogenetic proteins, but the regulatory mechanisms underlying DDR-induced gene expression remain to be determined. The aim of the present work was to elucidate the molecular mechanisms implicated in the expression of DDRs and to identify DDR-induced signaling pathways and target genes. Our data show that collagen I induces the expression of DDR1 in a dose- and time-dependent manner in primary human lung fibroblasts. Furthermore, activation of DDR2, JAK2, and ERK1/2 MAPK signaling pathways was essential for collagen I-induced DDR1 and matrix metalloproteinase 10 expression. Finally, inhibition of the ERK1/2 pathway abrogated DDR1 expression by blocking the recruitment of the transcription factor polyoma enhancer A-binding protein 3 to the DDR1 promoter. Our data provide new insights into the molecular mechanisms of collagen I-induced DDR1 expression and demonstrate an important role for ERK1/2 activation and the recruitment of polyoma enhancer-A binding protein 3 to the DDR1 promoter.

Lysophosphatidic acid induces MDA-MB-231 breast cancer cells migration through activation of PI3K/PAK1/ERK signaling

Background

Enhanced motility of cancer cells is a critical step in promoting tumor metastasis. Lysophosphatidic acid (LPA), representing the major mitogenic activity in serum, stimulates migration in various types of cancer cells. However, the underlying signaling mechanisms for LPA-induced motility of cancer cells remain to be elucidated.

Methodology/Principal Findings

In this study, we found that LPA dose-dependently stimulated migration of MDA-MB-231 breast cancer cells, with 10 µM being the most effective. LPA also increased ERK activity and the MEK inhibitor U0126 could block LPA-induced ERK activity and cell migration. In addition, LPA induced PAK1 activation while ERK activation and cell migration were inhibited by ectopic expression of an inactive mutant form of PAK1 in MDA-MB-231 cells. Furthermore, LPA increased PI3K activity, and the PI3K inhibitor LY294002 inhibited both LPA-induced PAK1/ERK activation and cell migration. Moreover, in the breast cancer cell, LPA treatment resulted in remarkable production of reactive oxygen species (ROS), while LPA-induced ROS generation, PI3K/PAK1/ERK activation and cell migration could be inhibited by N-acetyl-L-Cysteine, a scavenger of ROS.

Conclusions/Significance

Taken together, this study identifies a PI3K/PAK1/ERK signaling pathway for LPA-stimulated breast cancer cell migration. These data also suggest that ROS generation plays an essential role in the activation of LPA-stimulated PI3K/PAK1/ERK signaling and breast cancer cell migration. These findings may provide a basis for designing future therapeutic strategy for blocking breast cancer metastasis.

Rictor regulates MMP-9 activity and invasion through Raf-1-MEK-ERK signaling pathway in glioma cells

Glioblastoma multiforme (GBM) is the most common and highly aggressive type of primary brain tumor. Tumor-associated macrophages (TAMs) secrete TNF-α that activates important survival pathways including Akt (PKB)/mTOR network. The mammalian target of rapamycin (mTOR) network functions downstream of PI3K/Akt pathway to regulate cell growth, proliferation and survival. mTOR exists in two distinct complexes-mTORC1 and mTORC2 that differ in their components and sensitivity to rapamycin. The rapamycin-insensitive complex (mTORC2) consists of mTOR, mLST8, Rictor, mSin1 and Protor and regulates the actin cytoskeleton in addition to activating Akt (protein kinase B). The present study aimed to investigate the role of Rictor-a core component of mTORC2 in regulating proliferation, survival, and invasion in gliomas. siRNA-mediated loss of Rictor function in human glioma cell lines, LN18 and LN229 and in primary GBM cells resulted in elevated expression and activity of MMP-9 and significant increase in the invasive potential of these cells. Mechanistic studies revealed that the activation of Raf-1-MEK-ERK pathway was essential for induction of MMP-9 activity and enhanced invasion. Interestingly, ablation of Rictor did not affect TNF-α-induced MMP-9 activity and invasiveness suggesting that TNF-α in the microenvironment of tumor might overrule the function of Rictor as a negative regulator of MMP-9 and invasion. Silencing Rictor had no effect on the survival or proliferation in the cell lines in the presence or absence of TNF-α. Our findings identify a role for Rictor in bridging two major pathways-Akt (PKB)/mTOR and Raf-1-MEK-ERK in regulating MMP-9 activity and invasion of glioma tumor cells.

Stromal fibroblasts from the interface zone of human breast carcinomas induce an epithelial-mesenchymal transition-like state in breast cancer cells in vitro

Fibroblasts were extracted from tissue in tumor burden zones, distal normal zones and interface zones between tumor and normal tissue of human breast carcinomas, and the corresponding fibroblasts were designated as cancer-associated fibroblasts (CAFs), normal zone fibroblasts (NFs) and interface zone fibroblasts (INFs). The crosstalk between three types of fibroblasts and breast cancer cells was evaluated using an in vitro direct co-culture model. We found that INFs grew faster and expressed higher levels of fibroblast activation protein than did NFs and CAFs. Compared with CAFs and NFs, INFs grown with breast cancer cells were significantly more effective in inducing an epithelial-mesenchymal transition (EMT) in cancer cells, as indicated by induction of vimentin and N-cadherin and downregulation of E-cadherin. This EMT process was also accompanied by activation of extracellular signal-regulated kinase (ERK) and modulation of membrane-type 1 matrix metalloproteinase (MT1-MMP) expression. Additionally, INFs promoted breast cell migration to a larger extent compared with NFs and CAFs. Taken together, these findings indicate that INFs isolated from the tumor interface zone exhibited more robust biological modulatory activity than did NFs and CAFs isolated from normal and tumor zones of the same tumor tissue, suggesting that the interface zone of the tumor represents a dynamic region vital to tumor progression.

Modulation of metalloproteinase-9 in U87MG glioblastoma cells by A3 adenosine receptors

In this work, we investigated the biological functions of adenosine (ado) in metalloproteinase-9 (MMP-9) regulation in U87MG human glioblastoma cells. The nucleoside was able to increase both MMP-9 mRNA and protein levels through A3 receptors activation. We revealed that A3 receptor stimulation induced an increase of MMP-9 protein levels in cellular extracts of U87MG cells by phosphorylation of extracellular signal-regulated protein kinases (ERK1/2), c-Jun N-terminal kinase/stress-activated protein kinase (pJNK/SAPK), protein kinase B (Akt/PKB) and finally activator protein 1 (AP-1). A3 receptor activation stimulated also an increase of extracellular MMP-9 in the supernatants from U87MG glioblastoma cells. Finally, the Matrigel invasion assay demonstrated that A3 receptors, by inducing an increase in MMP-9 levels, was responsible for an increase of glioblastoma cells invasion. Collectively, these results suggest that ado, through A3 receptors activation, modulates MMP-9 protein levels and plays a role in increasing invasion of U87MG cells.

Therapeutic targets in malignant glioblastoma microenvironment

There is considerable evidence that the tissue microenvironment can suppress cancer and that microenvironment disruption is required for cancer growth and progression. Distortion of the microenvironment by tumor cells can promote growth, recruit nonmalignant cells that provide physiological resources, and facilitate invasion. Compared with the variable routes taken by cells to become cancers, the response of normal tissue to cancer is relatively consistent such that controlling cancer may be more readily achieved indirectly via the microenvironment. Here, we discuss 3 ideas about how the microenvironment, consisting of a vasculature, inflammatory cells, immune cells, growth factors, and extracellular matrix, might provide therapeutic targets in glioblastoma (GBM) in the context of radiotherapy (RT): (1) viable therapeutic targets exist in the GBM microenvironment, (2) RT alters the microenvironment of tissues and tumors; and (3) a potential benefit may be achieved by targeting the microenvironments induced by RT.

Ursolic acid inhibits IL-1beta or TNF-alpha-induced C6 glioma invasion through suppressing the association ZIP/p62 with PKC-zeta and downregulating the MMP-9 expression

Ursolic acid (UA), a constant constituent of Rosmarinus officinalis extracts, is a triterpenoid compound which has been shown to have antioxidant and anticarcinogenic properties. In the present study, we found that UA was able to reduce interleukin-1 beta (IL-1beta) or tumor necrosis-alpha (TNF-alpha)-induced rat C6 glioma cell invasion, which was examined by a reconstituted basement membrane in a set of transwell chambers. However, the inhibitory effect of UA did not influence cell proliferation or cause cell cytotoxity. The results analyzed by zymography assay and Western blotting revealed that the activity and expression of matrix metalloproteinase-9 (MMP-9) was eliminated by UA in a dose-dependent manner. Because MMP-9 is the target gene of the transcription factor nuclear factor-kappaB (NF-kappaB), we further investigated the effect of UA on the activity of NF-kappaB. As expected, UA upregulated the levels of IkappaBalpha (IkappaBalpha) and attenuated the nuclear translocation of p65. Furthermore, UA suppressed the IL-1beta or TNF-alpha-induced activation of protein kinase C-zeta (PKC-zeta). Our data showed UA potently inhibited the association of ZIP/p62 and PKC-zeta. Taken together, we demonstrated that UA could efficiently inhibit the interaction of ZIP/p62 and PKC-zeta. It also further suppressed the activation of NF-kappaB and downregulation of the MMP-9 protein, which in turn contributed to its inhibitory effects on IL-1beta or TNF-alpha-induced C6 glioma cell invasion. These results all showcase the potential UA has in the chemoprevention and treatment of cancer metastasis and invasion.

ERK and PI3K regulate different aspects of the epithelial to mesenchymal transition of mammary tumor cells induced by truncated MUC1

Epithelial to mesenchymal transition (EMT) integrates changes to cell morphology and signaling pathways resulting from modifications to the cell's transcriptional response. Different combinations of stimuli ignite this process in the contexts of development or tumor progression. The human MUC1 gene encodes multiple alternatively spliced forms of a polymorphic oncoprotein that is aberrantly expressed in epithelial malignancies. MUC1 is endowed with various signaling modules and has the potential to mediate proliferative and morphological changes characteristic of the progression of epithelial tumors. The tyrosine-rich cytoplasmic domain and the heavily glycosylated extracellular domain both play a role in MUC1-mediated signal transduction. However, the attribution of function to specific domains of MUC1 is difficult due to the concomitant presence of multiple forms of the protein, which stem from alternative splicing and proteolytic cleavage. Here we show that DA3 mouse mammary tumor cells stably transfected with a truncated genomic fragment of human MUC1 undergo EMT. In their EMT, these cells demonstrate altered [i] morphology, [ii] signaling pathways and [iii] expression of epithelial and mesenchymal markers. Similarly to well characterized human breast cancer cell lines, cells transfected with truncated MUC1 show an ERK-dependent increased spreading on fibronectin, and a PI3K-dependent enhancement of their proliferative rate.

Decursin and decursinol angelate inhibit VEGF-induced angiogenesis via suppression of the VEGFR-2-signaling pathway

Inhibition of angiogenesis is an attractive approach for the treatment of angiogenic diseases, such as cancer. Vascular endothelial growth factor (VEGF) is one of the most important activators of angiogenesis and interacts with the high-affinity tyrosine kinase receptors, VEGFR-1 and VEGFR-2. The pyranocoumarin compounds decursin and decursinol angelate isolated from the herb, Angelica gigas, are known to possess potent anti-inflammatory activities. However, little is known about their antiangiogenic activity or their underlying mechanisms. Here, we show the antiangiogenic effects of decursin and decursinol angelate using in vitro assays and in vivo animal experiments. Decursin and decursinol angelate inhibited VEGF-induced angiogenic processes in vitro, including proliferation, migration and tube formation of human umbilical vein endothelial cells. Decursin and decursinol angelate significantly suppressed neovessel formation in chick chorioallantoic membrane and tumor growth in a mouse model. The microvessel density in tumors treated with decursin for 14 days was significantly decreased compared with a vehicle control group. Decursin and decursinol angelate inhibited VEGF-induced phosphorylation of VEGFR-2, extracellular signal-regulated kinases and c-Jun N-terminal kinase mitogen-activated protein kinases. Taken together, these results demonstrate that decursin and decursinol angelate are novel candidates for inhibition of VEGF-induced angiogenesis.