Altered expression of metastasis-associated and regulatory molecules in effusions from breast cancer patients: a novel model for tumor progression

Harnessing Peptide-Functionalized Multivalent Gold Nanorods for Promoting Enhanced Gene Silencing and Managing Breast Cancer Metastasis

Small interfering RNA (siRNA) has become the cornerstone against undruggable targets and for managing metastatic breast cancer. However, an effective gene silencing approach is faced with a major challenge due to the delivery problem. In our present study, we have demonstrated efficient siRNA delivery, superior gene silencing, and inhibition of metastasis in triple-negative breast cancer cells (MDA-MB-231) using rod-shaped (aspect ratio: 4) multivalent peptide-functionalized gold nanoparticles and compared them to monovalent free peptide doses. Multivalency is a new concept in biology, and tuning the physical parameters of multivalent nanoparticles can enhance gene silencing and antitumor efficacy. We explored the effect of the multivalency of shape- and size-dependent peptide-functionalized gold nanoparticles in siRNA delivery. Our study demonstrates that peptide functionalization leads to reduced toxicity of the nanoparticles. Such designed peptide-functionalized nanorods also demonstrate antimetastatic efficacy in Notch1-silenced cells by preventing EMT progression in vitro. We have shown siRNA delivery in the hard-to-transfect primary cell line HUVEC and also demonstrated that the Notch1-silenced MDA-MB-231 cell line has failed to form nanobridge-mediated foci with the HUVEC in the co-culture of HUVEC and MDA-MB-231, which promote metastasis. This antimetastatic effect is further checked in a xenotransplant in vivo zebrafish model. In vivo studies also suggest that our designed nanoparticles mediated inhibition of micrometastasis due to silencing of the Notch1 gene. The outcome of our study highlights that the structure-activity relationship of multifunctional nanoparticles can be harnessed to modulate their biological activity.

Thoracic perfusion of lobaplatin combined with endostar for treating malignant pleural effusions: A meta-analysis and systematic review

INTRODUCTION

Lobaplatin is a new platinum-based cytotoxic chemotherapeutic agent. Endostar is an endogenous angiogenic inhibitor with implicated anti-tumor activity. This study was to investigate the efficacy and safety of thoracic perfusion of lobaplatin combined with endostar in the treatment of malignant pleural effusions (MPE).

METHODS

We searched the databases of Pubmed, the Cochrane Library, Embase, WanFang Data, and CNKI to select the studies regarding the efficacy and safety of lobaplatin combined with endostar to treat MPE. A total of 10[3-12] randomized controlled trials with 651 patients were included.

RESULTS

The objective response rate (P < .001, odds ratio = 4.08) and disease control rate (P < .001, odds ratio = 3.69) of lobaplatin combined with endostar were significantly higher than lobaplatin alone. In addition, lobaplatin combined with endostar remarkably promoted the quality of life of patients (P < .001, odds ratio = 3.93) compared with lobaplatin alone. Lobaplatin combined with endostar also promoted the quality of life of patients (P < .05, odds ratio = 2.56) compared with cisplatin combined with endostar. At the same time, the leukopenia rate (P < .05, odds ratio = .40) and the incidence of nausea and vomiting (P < .05, odds ratio = .38) of lobaplatin combined with endostar were significantly lower than that of cisplatin combined with endostar.

CONCLUSIONS

The efficacy of lobaplatin combined with endostar was superior to lobaplatin alone. The safety was higher than cisplatin combined with endostar through thoracic perfusion in treating MPE, which indicated that lobaplatin combined with endostar could be the effective agent for controlling MPE.

Intraductal xenografts show lobular carcinoma cells rely on their own extracellular matrix and LOXL1

Invasive lobular carcinoma (ILC) is the most frequent special histological subtype of breast cancer, typically characterized by loss of E-cadherin. It has clinical features distinct from other estrogen receptor-positive (ER+ ) breast cancers but the molecular mechanisms underlying its characteristic biology are poorly understood because we lack experimental models to study them. Here, we recapitulate the human disease, including its metastatic pattern, by grafting ILC-derived breast cancer cell lines, SUM-44 PE and MDA-MB-134-VI cells, into the mouse milk ducts. Using patient-derived intraductal xenografts from lobular and non-lobular ER+ HER2- tumors to compare global gene expression, we identify extracellular matrix modulation as a lobular carcinoma cell-intrinsic trait. Analysis of TCGA patient datasets shows matrisome signature is enriched in lobular carcinomas with overexpression of elastin, collagens, and the collagen modifying enzyme LOXL1. Treatment with the pan LOX inhibitor BAPN and silencing of LOXL1 expression decrease tumor growth, invasion, and metastasis by disrupting ECM structure resulting in decreased ER signaling. We conclude that LOXL1 inhibition is a promising therapeutic strategy for ILC.

Gene Editing of α6 Integrin Inhibits Muscle Invasive Networks and Increases Cell-Cell Biophysical Properties in Prostate Cancer

Human prostate cancer confined to the gland is indolent (low-risk), but tumors outside the capsule are aggressive (high-risk). Extracapsular extension requires invasion within and through a smooth muscle-structured environment. Because integrins respond to biomechanical cues, we used a gene editing approach to determine if a specific region of laminin-binding α6β1 integrin was required for smooth muscle invasion both in vitro and in vivo. Human tissue specimens showed prostate cancer invasion through smooth muscle and tumor coexpression of α6 integrin and E-cadherin in a cell-cell location and α6 integrin in a cell-extracellular matrix (ECM) distribution. Prostate cancer cells expressing α6 integrin (DU145 α6WT) produced a 3D invasive network on laminin-containing Matrigel and invaded into smooth muscle both in vitro and in vivo. In contrast, cells without α6 integrin (DU145 α6KO) and cells expressing an integrin mutant (DU145 α6AA) did not produce invasive networks, could not invade muscle both in vitro and in vivo, and surprisingly formed 3D cohesive clusters. Using electric cell-substrate impedance testing, cohesive clusters had up to a 30-fold increase in normalized resistance at 400 Hz (cell-cell impedance) as compared with the DU145 α6WT cells. In contrast, measurements at 40,000 Hz (cell-ECM coverage) showed that DU145 α6AA cells were two-fold decreased in normalized resistance and were defective in restoring resistance after a 1 μmol/L S1P challenge as compared with the DU145 α6WT cells. The results suggest that gene editing of a specific α6 integrin extracellular region, not required for normal tissue function, can generate a new biophysical cancer phenotype unable to invade the muscle, presenting a new therapeutic strategy for metastasis prevention in prostate cancer. SIGNIFICANCE: This study shows an innovative strategy to block prostate cancer metastasis and invasion in the muscle through gene editing of a specific α6 integrin extracellular region.

Cystathionine‑γ‑lyase promotes the metastasis of breast cancer via the VEGF signaling pathway

The present study aimed to provide data to support the association between cystathionine‑γ‑lyase (CSE) and breast cancer metastasis. Reverse transcription‑quantitative polymerase chain reaction, immunohistochemistry and western blot analysis were used to detect the mRNA and protein expression levels of CSE in human breast cancer tissues and cells. MTS and 5‑ethynyl‑2'‑deoxyuridine assays were used to assess cell viability and proliferation. Scratch wound and Transwell assays were conducted to determine cell migration and invasion. In addition, hydrogen sulfide determination was performed using the methylene blue method. The expression of CSE was upregulated in samples from patients with breast cancer that also exhibit lymph node metastasis, and in grade III and readily metastatic breast cancer cell lines. The proliferation, migration and invasion of breast cancer cells were examined in the present study, and tumor metastasis was observed in nude mice. The function of CSE in breast cancer metastasis depends on the vascular endothelial growth factor (VEGF) signaling pathway, a key mediator of angiogenesis that is crucial for the development and metastasis of tumors. CSE positively regulated the expression of VEGF and increased the levels of certain key proteins in the VEGF pathway, including the phosphoinositide (PI3K)/protein kinase B (AKT) pathway [PI3K, Akt and phosphorylated (p)Akt], focal adhesion kinase (FAK)‑paxillin pathway (FAK and paxillin) and rat sarcoma (Ras)‑mitogen‑activated protein kinase pathway [Ras, rapidly accelerated fibrosarcoma, extracellular signal‑regulated kinase (ERK)1/2 and pERK1/2]. Furthermore, the novel CSE inhibitor I157172 possessed antiproliferative and anti‑metastatic activities in early MDA‑MB‑231 metastatic breast cancer cells via inhibition of the VEGF signaling pathway, which further confirmed the role of CSE in breast cancer metastasis. Overall, these data demonstrate for the first time, to the best of our knowledge, that the functions of CSE in breast cancer metastasis are associated with the VEGF signaling pathway.

ALDOLASE A regulates invasion of bladder cancer cells via E-cadherin-EGFR signaling

Glycolysis and glycogenesis are known to be tightly associated with cancer cell migration. However, their roles in bladder cancer have not been reported. In this study, ALDOLASE A (ALDOA) was identified in a coexpression network generated using glycolysis- and glycogenesis-related genes in Kyoto Encyclopedia of Genes and Genomes. ALDOA was located in the central region in the network, and the cancer genome atlas (TCGA) data suggest that ALDOA expression levels are associated with viability in patients with cancer at the middle and late stages. Bladder cancer cell lines, T24 and RT4, were used to knockdown (sh) or overexpress (OE) ALODA to analyze its role. The sh-ALDOA reduced cell viability, colony formation rate, and invasion cell number; while OE had an opposite effect compared with sh-ALDOA. Further, the sh-ALDOA expression induced E-cadherin level while reduced N-cadherin and vimentin levels. The OE cells reduced E-cadherin and induced N-cadherin and vimentin levels. In addition, epidermal growth factor receptor (EGFR), mitogen-activated protein kinase (MAPK), and AKT serine/threonine kinase (AKT) phosphorylation levels are all reduced in sh-ALODA while activated in OE cells compared with the control group. But either sh-ALODA or OE did not change total protein levels of EGFR, MAPK, and AKT. To further analyze E-cadherin function in ALDOA regulation on bladder cancer cells, sh-ALDOA and sh-E-cadherin were cotransfected in T24 and RT4 cells. The results indicated that sh-ALDOA and sh-E-cadherin expressions eliminated sh-ALDOA function, resulting similar cell viability, colony formation rate, and invasion cell number with control group. Also, sh-ALDOA and shE-cadherin expressions increased EGFR, MAPK, and AKT phosphorylation levels; and the levels were similar to the control group. But, sh-ALDOA and sh-E-cadherin expressions did not change N-cadherin and vimentin levels, which maintain similar levels with sh-ALDOA-expressing cells. Taken together, these results suggest that ALDOA might play an important function in bladder cancer and its action may be though E-cadherin-EGFR signaling.

Co-Administration of Fish Oil With Signal Transduction Inhibitors Has Anti-Migration Effects in Breast Cancer Cell Lines, in vitro

Background:

There is an urgent need for new therapies to treat cancer metastasis. Fish oil, with high omega 3 fatty acid content, has shown anticancer activity and signal transduction inhibitors have shown anti-metastatic properties.

Objective:

To provide preliminary in vitro data on the anti-migration potential of signal transduction inhibitors and co-administered fish oil.

Methods:

MCF-7, TamR and FasR breast cancer cell lines were used to determine the effects of combinations of PD98059, LY294002 and fish oil in growth assays. Modulations of p-Src and COX-2, both mediators of motility and invasion, were then determined by Western blotting and IHC to ascertain effects on migration potential.

Results:

Migration rates for the three cell lines examined were ranked: FasR>TamR>MCF-7 (p <0.05). Addition of fish oil reduced the number of TamR cells migrating after 48h (p <0.05), while the addition of PD98059 and LY294002 also decreased migratory potential of TamR cells (p <0.05). Addition of PD98059 and LY294002 to TamR cells did not result in a significant decrease in p-Src levels; as was the case when PD98059, LY294002 and 4-hydroxytamoxifen were added to MCF-7 cells. However, the co-administration of fish oil markedly reduced p-Src and COX-2 expression in both cell lines.

Conclusion:

Co-administration of a commercial fish oil with signal transduction inhibitors results in decreased cell migration via an unknown co-operative mechanism and could constitute a novel approach for the treatment of breast cancer metastasis.

Genetics of metastasis: melanoma and other cancers

Melanoma is a malignant neoplasm of melanocytes that accounts for the majority of skin cancer deaths despite comprising less than 5% of all cutaneous malignancies. Its incidence has increased faster than that of any other cancer over the past half-century and the annual costs of treatment in the United States alone have risen rapidly. Although the majority of primary melanomas are cured with local excision, metastatic melanoma historically carries a grim prognosis, with a median survival of 9 months and a long-term survival rate of 10%. Given the urgent need to develop treatment strategies for metastatic melanoma and the explosion of genetic technologies over the past 20 years, there has been extensive research into the genetic alterations that cause melanocytes to become malignant. More recently, efforts have focused on the genetic changes that drive melanoma metastasis. This review aims to summarize the current knowledge of the genetics of primary cutaneous and ocular melanoma, the genetic changes associated with metastasis in melanoma and other cancer types, and non-genetic factors that may contribute to metastasis.

Estrogen, progesterone, and HER2/neu receptor discordance between primary and metastatic breast tumours-a review

Discordance in estrogen (ER), progesterone (PR), and HER2/neu status between primary breast tumours and metastatic disease is well recognized. In this review, we highlight how receptor discordance between primary tumours and paired metastasis can help elucidate the mechanism of metastasis but can also effect patient management and the design of future trials. Discordance rates and ranges were available from 47 studies (3384 matched primary and metastatic pairs) reporting ER, PR, and HER2/neu expression for both primary and metastatic sites. Median discordance rates for ER, PR, and HER2/neu were 14 % (range 0-67 %, IQR 9-25 %), 21 % (range 0-62 %, IQR 15-41 %), and 10 % (range 0-44 %, IQR 4-17 %), respectively. Loss of receptor expression was more common (9.17 %) than gain (4.51 %). Discordance rates varied amongst site of metastasis with ER discordance being highest in bone metastases suggesting that discordance is a true biological phenomenon. Discordance rates vary for both the biomarker and the metastatic site. Loss of expression is more common than gain. This can affect patient management as it can lead to a reduction in both the efficacy and availability of potential therapeutic agents. Future studies are recommended to explore both the mechanisms of discordance as well as its impact on patient outcome and management.

The tumor microenvironment disarms CD8+ T lymphocyte function via a miR-26a-EZH2 axis

One of the most important factors that limit the potency of CD8⁺ cytotoxic T lymphocyte (CTL) responses is the tumor microenvironment (TME). Here, we provide evidence that miR-26a is a negative regulator of CTL function in the TME. Specifically, we identified miR-26a as a crucial suppressor gene in CTLs from the TME, as we found that, miR-26a expression was elevated in CTLs to respond to TME secretome stimulation. CTLs from miR-26a-transgenic mice showed impaired IFNγ and granzyme B production in response to their cognate antigen. Conversely, we found that miR-26a inhibition in CTLs could effectively increase the cytotoxicity and suppress tumor growth. Mechanically, we identified EZH2 as a direct target of miR-26a. miR-26a and EZH2 expression were found to be inversely correlated in CTLs, and the inhibition of EZH2 in CTLs impairs CTL function. These functional correlations were validated in a cohort of non-small cell lung cancer patients, indicating that the miR-26a-EZH2 axis is clinically relevant. Our findings suggested that miR-26a silencing as a novel strategy to improve the efficacy of CTL-based cancer immunotherapy.

Neurotrophin signaling in cancer stem cells

Cancer stem cells (CSCs), are thought to be at the origin of tumor development and resistance to therapies. Thus, a better understanding of the molecular mechanisms involved in the control of CSC stemness is essential to the design of more effective therapies for cancer patients. Cancer cell stemness and the subsequent expansion of CSCs are regulated by micro-environmental signals including neurotrophins. Over the years, the roles of neurotrophins in tumor development have been well established and regularly reviewed. Especially, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are reported to stimulate tumor cell proliferation, survival, migration and/or invasion, and favors tumor angiogenesis. More recently, neurotrophins have been reported to regulate CSCs. This review briefly presents neurotrophins and their receptors, summarizes their roles in different cancers, and discusses the emerging evidence of neurotrophins-induced enrichment of CSCs as well as the involved signaling pathways.

Protein deregulation associated with breast cancer metastasis

Breast cancer is one of the most prevalent malignancies worldwide. It consists of a group of tumor cells that have the ability to grow uncontrollably, overcome replicative senescence (tumor progression) and metastasize within the body. Metastases are processes that consist of an array of complex gene dysregulation events. Although these processes are still not fully understood, the dysregulation of a number of key proteins must take place if the tumor cells are to disseminate and metastasize. It is now widely accepted that future effective and innovative treatments of cancer metastasis will have to encompass all the major components of malignant transformation. For this reason, much research is now being carried out into the mechanisms that govern the malignant transformation processes. Recent research has identified key genes involved in the development of metastases, as well as their mechanisms of action. A detailed understanding of the encoded proteins and their interrelationship generates the possibility of developing novel therapeutic approaches. This review will focus on a select group of proteins, often deregulated in breast cancer metastasis, which have shown therapeutic promise, notably, EMT, E-cadherin, Osteopontin, PEA3, Transforming Growth Factor Beta (TGF-β) and Ran.

CD147: regulator of hyaluronan signaling in invasiveness and chemoresistance

Major determinants that influence negative outcome in cancer patients are the abilities of cancer cells to resist current therapies and to invade surrounding host tissue, consequently leading to local and metastatic dissemination. Hyaluronan (HA), a prominent constituent of the tumor microenvironment, not only provides structural support but also interacts with cell surface receptors, especially CD44, that influence cooperative signaling pathways leading to chemoresistance and invasiveness. CD147 (emmprin; basigin) is a member of the Ig superfamily that has also been strongly implicated in chemoresistance and invasiveness. CD147 both regulates HA synthesis and interacts with the HA receptors, CD44, and LYVE-1. Increased CD147 expression induces formation of multiprotein complexes containing CD44 (or LYVE-1) as well as members of the membrane-type matrix metalloproteinase, receptor tyrosine kinase, ABC drug transporter, or monocarboxylate transporter families, which become assembled in specialized lipid raft domains along with CD147 itself. In each case, multivalent HA-receptor interactions are essential for formation or stabilization of the lipid raft complexes and for downstream signaling pathways or transporter activities that are driven by these complexes. We conclude that cooperativity between HA, HA receptors, and CD147 may be a major driver of the interconnected pathways of invasiveness and chemoresistance widely critical to malignancy.

The role of the cell-cell interactions in cancer progression

In the field of cancer research, scientific investigations are based on analysing differences in the secretome, the proteome, the transcriptome, the expression of cell surface molecules, and the deregulation of signal transduction pathways between neoplastic and normal cells. Accumulating evidence indicates a crucial role in carcinogenesis concerning not only stromal cells but also normal cells from target organs and tissue where tumours emerge. The tumour microenvironment (TME) definitively plays an important role in regulating neighbouring cell behaviour. To date, limited attention has been focused upon interactions between cancer cells and normal cells. This review concentrates on the interactions between stromal and healthy cells from the TME in cancer development. In the article, the authors also describe mutations, genes and proteins expression pattern that are involved in tumour development in target organ.

Role of p38 MAP Kinase Signal Transduction in Solid Tumors

Mitogen-activated protein kinases (MAPKs) mediate a wide variety of cellular behaviors in response to extracellular stimuli. One of the main subgroups, the p38 MAP kinases, has been implicated in a wide range of complex biologic processes, such as cell proliferation, cell differentiation, cell death, cell migration, and invasion. Dysregulation of p38 MAPK levels in patients are associated with advanced stages and short survival in cancer patients (e.g., prostate, breast, bladder, liver, and lung cancer). p38 MAPK plays a dual role as a regulator of cell death, and it can either mediate cell survival or cell death depending not only on the type of stimulus but also in a cell type specific manner. In addition to modulating cell survival, an essential role of p38 MAPK in modulation of cell migration and invasion offers a distinct opportunity to target this pathway with respect to tumor metastasis. The specific function of p38 MAPK appears to depend not only on the cell type but also on the stimuli and/or the isoform that is activated. p38 MAPK signaling pathway is activated in response to diverse stimuli and mediates its function by components downstream of p38. Extrapolation of the knowledge gained from laboratory findings is essential to address the clinical significance of p38 MAPK signaling pathways. The goal of this review is to provide an overview on recent progress made in defining the functions of p38 MAPK pathways with respect to solid tumor biology and generate testable hypothesis with respect to the role of p38 MAPK as an attractive target for intervention of solid tumors.

The Complex Interaction of Matrix Metalloproteinases in the Migration of Cancer Cells through Breast Tissue Stroma

Breast cancer mortality is directly linked to metastatic spread. The metastatic cell must exhibit a complex phenotype that includes the capacity to escape from the primary tumour mass, invade the surrounding normal tissue, and penetrate into the circulation before proliferating in the parenchyma of distant organs to produce a metastasis. In the normal breast, cellular structures change cyclically in response to ovarian hormones leading to regulated cell proliferation and apoptosis. Matrix metalloproteinases (MMPs) are a family of zinc dependent endopeptidases. Their primary function is degradation of proteins in the extracellular matrix to allow ductal progression through the basement membrane. A complex balance between matrix metalloproteinases and their inhibitors regulate these changes. These proteinases interact with cytokines, growth factors, and tumour necrosis factors to stimulate branching morphologies in normal breast tissues. In breast cancer this process is disrupted facilitating tumour progression and metastasis and inhibiting apoptosis increasing the life of the metastatic cells. This paper highlights the role of matrix metalloproteinases in cell progression through the breast stroma and reviews the complex relationships between the different proteinases and their inhibitors in relation to breast cancer cells as they metastasise.

Non-Hodgkin's B-cell lymphoma: advances in molecular strategies targeting drug resistance

Non-Hodgkin's lymphoma (NHL) is a heterogeneous class of cancers displaying a diverse range of biological phenotypes, clinical behaviours and prognoses. Standard treatments for B-cell NHL are anthracycline-based combinatorial chemotherapy regimens composed of cyclophosphamide, doxorubicin, vincristine and prednisolone. Even though complete response rates of 40-50% with chemotherapy can be attained, a substantial proportion of patients relapse, resulting in 3-year overall survival rates of about 30%. Relapsed lymphomas are refractory to subsequent treatments with the initial chemotherapy regimen and can exhibit cross-resistance to a wide variety of anticancer drugs. The emergence of acquired chemoresistance thus poses a challenge in the clinic preventing the successful treatment and cure of disseminated B-cell lymphomas. Gene-expression analyses have increased our understanding of the molecular basis of chemotherapy resistance and identified rational targets for drug interventions to prevent and treat relapsed/refractory diffuse large B-cell lymphoma. Acquisition of drug resistance in lymphoma is in part driven by the inherent genetic heterogeneity and instability of the tumour cells. Due to the genetic heterogeneity of B-cell NHL, many different pathways leading to drug resistance have been identified. Successful treatment of chemoresistant NHL will thus require the rational design of combinatorial drugs targeting multiple pathways specific to different subtypes of B-cell NHL as well as the development of personalized approaches to address patient-to-patient genetic heterogeneity. This review highlights the new insights into the molecular basis of chemorefractory B-cell NHL that are facilitating the rational design of novel strategies to overcome drug resistance.

Recombinant viral protein VP1 suppresses HER-2 expression and migration/metastasis of breast cancer

Breast cancer is one of the most common cancers in women worldwide and metastasis is the major cause of breast cancer death. Development of new therapeutic agents for inhibiting breast cancer metastasis is therefore an urgent need. We previously demonstrated that recombinant DNA-derived viral capsid protein VP1 (rVP1) of foot-and-mouth disease virus-induced apoptosis of MCF-7 breast cancer cells in vitro. Here, we investigated whether rVP1 exhibits any inhibitory effects on migration/metastasis and human epidermal growth factor receptor 2 (HER-2), a well-known biomarker for poor prognosis of breast cancer. The effects of rVP1 on cancer cell migration/invasion and metastasis were evaluated using Transwell migration assay and animal cancer models of metastasis. Western blotting, RT-PCR, flow cytometry, immunohistochemistry, and immunofluorescence staining techniques were used to investigate the effects of rVP1 on HER-2 and signal transduction mediators. Non-cytotoxic concentrations of rVP1-induced mesenchymal-epithelial transition and significantly suppressed AP-2α and HER-2 expression as well as the migration and invasion of a variety of breast cancer cell lines in a β1-integrin-dependent manner in vitro. Gross and histopathologic examinations showed that rVP1 also suppressed metastasis of several breast cancer cell lines, including HER-2-overexpressing SK-BR-3 and BT-474 cells to lung, liver, or peripheral lymph node in orthotopic allograft/xenograft murine models. In addition, rVP1 significantly prolonged survival in breast cancer-bearing mice. Notably, no apparent side effects of rVP1 were detected, as shown by normal complete blood count levels and serum biochemistry profiles, including AST, ALT, BUN, and creatine. This study demonstrates that rVP1 suppresses the migration, invasion, and metastasis of breast cancer cells via binding to β1 integrin receptor and down-regulation of AP-2α and HER-2 expression. The effectiveness of rVP1 on inhibiting migration/metastasis of breast cancer and HER-2 expression suggests that it may be suitable for serving as potential therapeutics for metastatic breast cancer particularly HER-2-overexpressing cancer.

Regulation of invadopodia formation and activity by CD147

A defining feature of malignant tumor progression is cellular penetration through the basement membrane and interstitial matrices that separate various cellular compartments. Accumulating evidence supports the notion that invasive cells employ specialized structures termed invadopodia to breach these structural barriers. Invadopodia are actin-based, lipid-raft-enriched membrane protrusions containing membrane-type-1 matrix metalloproteinase (MT1-MMP; also known as matrix metalloproteinase 14; MMP14) and several signaling proteins. CD147 (emmprin, basigin), an immunoglobulin superfamily protein that is associated with tumor invasion and metastasis, induces the synthesis of various matrix metalloproteinases in many systems. In this study we show that upregulation of CD147 is sufficient to induce MT1-MMP expression, invasiveness and formation of invadopodia-like structures in non-transformed, non-invasive, breast epithelial cells. We also demonstrate that CD147 and MT1-MMP are in close proximity within these invadopodia-like structures and co-fractionate in membrane compartments with the properties of lipid rafts. Moreover, manipulation of CD147 levels in invasive breast carcinoma cells causes corresponding changes in MT1-MMP expression, invasiveness and invadopodia formation and activity. These findings indicate that CD147 regulates invadopodia formation and activity, probably through assembly of MT1-MMP-containing complexes within lipid-raft domains of the invadopodia.

Long-term outcome of pleurodesis with OK-432 in metastatic breast cancer: a new risk model for success from an analysis of 75 cases

BACKGROUND

Malignant pleural effusion is a common and devastating complication of metastatic breast cancer. This occurs in about 30% of patients with metastatic breast cancer during the clinical course, and chemical pleurodesis is sometimes performed to relieve dyspnea. However, the long-term outcome of pleurodesis and factors affecting successful pleurodesis have not been clarified.

OBJECTIVES

The aim of this analysis is to evaluate the long-term outcome of pleurodesis and to identify risk factors associated with success.

METHODS

Data on 75 patients who had undergone chemical pleurodesis with OK-432 for pleural effusion due to metastatic breast cancer were reviewed retrospectively. The primary outcomes were success rate and pleural progression-free survival (PPFS) rate.

RESULTS

The median duration of follow-up was 134 days (range 8-975 days). During this period, 22 patients re-accumulated pleural fluid. The overall success rate was 70.5%. The 4-, 8- and 12-week PPFS rates were 88.0, 84.0 and 78.7% respectively. Multivariate analysis identified three unfavorable factors that were independently associated with unsuccessful pleurodesis, including estrogen-receptor negative status, a 24-h drainage volume of more than 100 mL before extubation and NSAID use. The PPFS rate at median follow-up was 93.5% in the low-risk group (n = 41, 0 or 1 unfavorable factor) and 55.1% in the high-risk group (n = 34, 2 or 3 unfavorable factors). The difference between the PPFS curves of the two risk groups was statistically significant (P < 0.001).

CONCLUSIONS

Pleurodesis for metastatic breast cancer was efficacious in controlling malignant pleural effusion. Our simple new risk model warrants further studies.

NOTCH-1 and NOTCH-4 are novel gene targets of PEA3 in breast cancer: novel therapeutic implications

Introduction

Women with triple-negative breast cancer have the worst prognosis, frequently present with metastatic tumors and have few targeted therapy options. Notch-1 and Notch-4 are potent breast oncogenes that are overexpressed in triple-negative and other subtypes of breast cancer. PEA3, an ETS transcription factor, is also overexpressed in triple-negative and other breast cancer subtypes. We investigated whether PEA3 could be the critical transcriptional activator of Notch receptors in MDA-MB-231 and other breast cancer cells.

Methods

Real-time PCR and Western blot analysis were performed to detect Notch-1, Notch-2, Notch-3 and Notch-4 receptor expression in breast cancer cells when PEA3 was knocked down by siRNA. Chromatin immunoprecipitation was performed to identify promoter regions for Notch genes that recruited PEA3. TAM-67 and c-Jun siRNA were used to identify that c-Jun was necessary for PEA3 enrichment on the Notch-4 promoter. A Notch-4 luciferase reporter was used to confirm that endogenous PEA3 or AP-1 activated the Notch-4 promoter region. Cell cycle analysis, trypan blue exclusion, annexin V flow cytometry, colony formation assay and an in vivo xenograft study were performed to determine the biological significance of targeting PEA3 via siRNA, Notch signaling via a γ-secretase inhibitor, or both.

Results

Herein we provide new evidence for transcriptional regulation of Notch by PEA3 in breast cancer. PEA3 activates Notch-1 transcription in MCF-7, MDA-MB-231 and SKBr3 breast cancer cells. PEA3 activates Notch-4 transcription in MDA-MB-231 cells where PEA3 levels are endogenously high. In SKBr3 and BT474 breast cancer cells where PEA3 levels are low, overexpression of PEA3 increases Notch-4 transcripts. Chromatin immunoprecipitation confirmed the enrichment of PEA3 on Notch-1 and Notch-4 promoters in MDA-MB-231 cells. PEA3 recruitment to Notch-1 was AP-1-independent, whereas PEA3 recruitment to Notch-4 was c-JUN-dependent. Importantly, the combined inhibition of Notch signaling via a γ-secretase inhibitor (MRK-003 GSI) and knockdown of PEA3 arrested growth in the G₁ phase, decreased both anchorage-dependent and anchorage-independent growth and significantly increased apoptotic cells in vitro. Moreover, either PEA3 knockdown or MRK-003 GSI treatment significantly reduced tumor growth of MDA-MB-231 xenografts in vivo.

Conclusions

Taken together, the results from this study demonstrate for the first time that Notch-1 and Notch-4 are novel transcriptional targets of PEA3 in breast cancer cells. Targeting of PEA3 and/or Notch pathways might provide a new therapeutic strategy for triple-negative and possibly other breast cancer subtypes.

Expression of CD147 is associated with prostate cancer progression

Novel molecular markers that are associated with prostate cancer (PCa) progression will provide valuable information in the diagnosis and treatment of the disease. Extracellular matrix metalloproteinase inducer (CD147) has been demonstrated to be involved in tumor invasion, metastasis, growth and survival. In our study, we examined whether the expression of CD147 can be used as a prognostic marker for predicting PCa progression. Tissue samples from 240 patients who received radical prostatectomy for PCa were obtained. CD147 expression in these samples was evaluated using immunohistochemical staining with a monoclonal antibody specifically against CD147. Increased expression of CD147 was correlated with higher Gleason scores (GS), positive surgical margin, prostate-specific antigen (PSA) failure, metastasis and reduced overall survival. Both univariate Cox regression analysis and multivariate analysis including competing biological variables demonstrated that increased CD147 expression was associated with increased risk for reduced PSA failure-free, metastasis-free and overall survival. Kaplan-Meier survival curves showed that the CD147 overexpression was a significant predictor for the PSA failure-free, metastasis-free and the overall survival in both pT2 and pT3 PCa patients. More significantly, higher expression of CD147 can serve as an independent prognostic predictor for PSA failure-free survival in PCa patients when they are stratified by GS. Our study results demonstrate the involvement of CD147 in PCa progression and suggest its potential role as an independent predictor of biochemical recurrence, development of metastasis and reduced overall survival in PCa.

Extracellular matrix metalloproteinase inducer is a negative prognostic factor of pediatric medulloblastoma

Medulloblastoma (MB) is the most common embryonal CNS tumor of childhood. Its survival rates have significantly improved over the years due to developments in diagnostic techniques and therapeutic strategies. However, it is still an important cause of cancer-related deaths in children. Extracellular matrix metalloproteinase inducer (EMMPRIN) is a member of the immunoglobulin family and a glycoprotein enriched on the surface of many types of tumor cells. Therefore, the aim of this study was to investigate whether the expression patterns of EMMPRIN may predict the clinical prognosis in MB. EMMPRIN expression in a series of 56 MB with various grades and pathological types was analyzed by immunohistochemical staining on paraffin-embedded sections. Then, the correlation of EMMPRIN expression patterns with clinical-pathological features of patients and its prognostic relevance were determined. Immunohistochemistry revealed that the positive expression rate of EMMPRIN in MB (75.0%, 42/56) was significantly higher than that in normal cerebellums (6.7%, 2/30, p < 0.001). In addition, EMMPRIN expression in MB was up-regulated in higher metastatic stage (p < 0.01), aggressive histopathological type (p < 0.005), necrosis (p < 0.01), as well as with undifferentiated tumor (p < 0.01). Furthermore, over-expression of EMMPRIN correlated significantly with poor prognosis (0.01 < p < 0.05) and represented an independent prognostic marker of overall survival on multivariate analysis (p = 0.01). Our study suggests that EMMPRIN expression was associated with the progression of MB and its over-activation may be an important predictor of poor survival in this patient cohort. Therefore, EMMPRIN may be regarded both as a prognostic factor and a therapeutic target for MB.

Netrin-4 is upregulated in breast carcinoma effusions compared to corresponding solid tumors

We recently identified overexpression of the NTN4 gene in breast carcinoma effusions compared to primary carcinomas using gene-expression arrays. The objective of this study was to validate this finding at protein level and analyze the clinical role of Netrin-4 in breast carcinoma effusions. We additionally studied Netrin-4 expression and its clinical relevance in Müllerian (ovarian, peritoneal, and tubal) carcinoma effusions. Sections from 82 breast carcinomas (53 effusions and 29 solid tumors) and 57 Müllerian carcinoma effusions were stained for Netrin-4 using immunohistochemistry. Immunoreactivity was scored in carcinoma cells and analyzed for association with clinicopathologic parameters, including survival. In breast carcinoma, expression of Netrin-4 was detected in carcinoma cells in 30/53 (57%) effusions compared to 3/29 (10%) solid tumors (P < 0.001). Netrin-4 was further expressed in 31/57 (54%) Müllerian carcinoma effusions. No association was found between Netrin-4 expression in breast or Müllerian carcinoma effusions and clinicopathologic parameters, including survival. Our data provide validation on protein level of upregulated Netrin-4 expression in breast carcinoma effusions. The frequent expression of Netrin-4 in Müllerian carcinoma effusions suggests a biological role for this molecule in metastases from gynecological malignancies. Netrin-4 expression in effusions does not appear to be a predictor of disease outcome.

CD105 (Endoglin) expression in breast carcinoma effusions is a marker of poor survival

We analyzed the expression and clinical role of endoglin (CD105) in breast carcinoma effusions. Endoglin levels were measured in 36 effusion supernatants by ELISA and studied for association with the cancer-associated markers calprotectin, VEGF, and the VEGF receptor sFlt1. Endoglin expression was further studied in 46 effusions and 22 primary carcinomas using immunohistochemistry. The four secreted molecules were detected in all specimens and their levels significantly correlated (p < 0.001). In effusions, endoglin was localized to carcinoma cells and reactive mesothelium using immunohistochemistry. Tumor cell expression was higher in effusions compared to primary carcinomas (p = 0.025), and in post-chemotherapy compared to pre-chemotherapy effusions (p = 0.017). Higher tumor endoglin expression was associated with poor overall (p = 0.021) and disease-free (p = 0.032) survival in univariate analysis, and was an independent predictor in Cox multivariate analysis (p = 0.001 and p = 0.038, respectively). Our data suggest that endoglin may be an important therapeutic target in metastatic breast cancer.

Overexpression of SCC-S2 correlates with lymph node metastasis and poor prognosis in patients with non-small-cell lung cancer

The objective of the current study was to investigate the expression pattern and clinicopathological significance of SCC-S2 in patients with non-small-cell lung cancer (NSCLC). The expression profile of SCC-S2 in NSCLC tissues and adjacent noncancerous lung tissues was detected by real-time RT-PCR, western blot analysis, and immunohistochemistry. In 25 lung cancer tissues examined, 18 (72%) of them exhibited stronger levels of SCC-S2 mRNA compared with their corresponding normal tissues. SCC-S2 protein level was up-regulated in cancerous lung tissues compared to adjacent normal tissue. Moreover, the expression level of SCC-S2 in 93 archived NSCLC tissues was measured by immunohistochemical staining. SCC-S2 was found to be overexpressed in 71 of 93 (76.3%) human lung cancer samples and correlated with lymph node metastasis (P = 0.0181), p-TNM stage (P = 0.0042), Ki-67 expression (P = 0.0028), and poor survival (P = 0.012). In addition, depleting SCC-S2 expression by small-interfering RNA inhibited growth and invasion in lung cell lines. These results indicate that SCC-S2 plays an important role in NSCLC and might be a useful therapeutic target of NSCLC.

Breast carcinoma cells in primary tumors and effusions have different gene array profiles

The detection of breast carcinoma cells in effusions is associated with rapidly fatal outcome, but these cells are poorly characterized at the molecular level. This study compared the gene array signatures of breast carcinoma cells in primary carcinomas and effusions. The genetic signature of 10 primary tumors and 10 effusions was analyzed using the Array-Ready Oligo set for the Human Genome platform. Results for selected genes were validated using PCR, Western blotting, and immunohistochemistry. Array analysis identified 255 significantly downregulated and 96 upregulated genes in the effusion samples. The majority of differentially expressed genes were part of pathways involved in focal adhesion, extracellular matrix-cell interaction, and the regulation of the actin cytoskeleton. Genes that were upregulated in effusions included KRT8, BCAR1, CLDN4, VIL2, while DCN, CLDN19, ITGA7, and ITGA5 were downregulated at this anatomic site. PCR, Western blotting, and immunohistochemistry confirmed the array findings for BCAR1, CLDN4, VIL2, and DCN. Our data show that breast carcinoma cells in primary carcinomas and effusions have different gene expression signatures, and differentially express a large number of molecules related to adhesion, motility, and metastasis. These differences may have a critical role in designing therapy and in prognostication for patients with metastatic disease localized to the serosal cavities.

Methods for simultaneous measurement of apoptosis and cell surface phenotype of epithelial cells in effusions by flow cytometry

We describe here a protocol for the detection of epithelial cells in effusions combined with quantification of apoptosis by flow cytometry (FCM). The procedure described consists of the following stages: culturing and induction of apoptosis by staurosporine in control ovarian carcinoma cell lines (SKOV-3 and OVCAR-8); preparation of effusion specimens and cell lines for staining; staining of cancer cells in effusions and cell lines for cell surface markers (Ber-EP4, EpCAM and CD45) and intracellular/nuclear markers of apoptosis (cleaved caspase-3 and caspase-8, and incorporated deoxyuridine triphosphates); and FCM analysis of stained cell lines and effusions. This protocol identifies a specific cell population in cytologically heterogeneous clinical specimens and applies two methods to measure different aspects of apoptosis in the cell population of interest. The cleaved caspase and deoxyuridine triphosphate incorporation FCM assays are run in parallel and require (including sample preparation, staining, instrument adjustment and data acquisition) 8 h. The culturing of cell lines requires 2-3 days and induction of apoptosis requires 16 h.

EMMPRIN expression as a prognostic factor in radiotherapy of cervical cancer

PURPOSE

Overexpression of extracellular matrix metalloproteinase inducer (EMMPRIN), a member of the immunoglobulin family and a glycoprotein enriched on the surface of many types of tumor cells, has been reported to be linked to invasion, metastasis, growth, and survival of malignant cells. Cervical cancer, the second most prevalent cancer in women worldwide and the fifth leading cause of cancer deaths, responds to radiotherapy variably, with 30% of cases recurring after therapy. The purpose of this study was to determine whether expression of EMMPRIN affects the response of cervical cancer to radiation therapy, and whether this membrane protein can be used as a prognostic marker for cervical cancer.

EXPERIMENTAL DESIGN

The retrospective cohort study included 82 patients with invasive cervical cancer referred to the Department of Gynecologic Oncology at The Cancer Hospital of Fudan University (Shanghai) between 1991 and 2000. These patients were treated with brachytherapy at a dose of 15 Gy at point A before radical hysterectomy. Expression of EMMPRIN in cervical tumor specimens was examined by immunohistochemistry staining before and after brachytherapy and scored for both staining intensity and percentage of tumor cells stained. EMMPRIN immunoreactivity and clinicopathologic data were analyzed with respect to survival end points using univariate and multivariate approaches.

RESULTS

The frequency of EMMPRIN overexpression was 52.4% in primary cervical cancer. After brachytherapy, EMMPRIN overexpression was significantly reduced (13.4%) compared with corresponding tumor before brachytherapy (P = 0.032). EMMPRIN expression was associated with pelvic lymph node metastasis (P = 0.026) and reduction in primary tumor volume following brachytherapy (P = 0.008). Although EMMPRIN expression before or after brachytherapy did not correlate with tumor-specific survival, but increased expression of EMMPRIN following brachytherapy tended to predict poor outcomes by univariate survival analysis (P = 0.0008). In addition, lymph vascular space invasion, deep stromal invasion, and lymph node metastasis were significantly associated with poor prognosis. In multivariate analysis, the independent prognostic factors for tumor-specific survival included the decreased expression of EMMPRIN after brachytherapy (P = 0.002; hazard ratio, 0.339; 95% confidence interval, 0.172-0.672) as well as lymph node metastasis (P = 0.044; hazard ratio, 2.053; 95% confidence interval, 1.020-4.133).

CONCLUSION

Expression of EMMPRIN was associated with a decrease in the reduction of cervical tumor following brachytherapy, and increased EMMPRIN expression after brachytherapy seemed to be an important predictor of poor survival in this patient cohort. Our study suggests that expression of EMMPRIN confers resistance to radiotherapy. Therefore, EMMPRIN expression in cervical cancer may be regarded both as a prognostic factor and a therapeutic target.

Expression of the chromatin remodeling factor Rsf-1 is down-regulated in breast carcinoma effusions

We recently identified Rsf-1, a chromatin-remodeling gene, as a potential oncogene that is frequently amplified and overexpressed in ovarian serous carcinoma, and demonstrated that its expression in carcinoma cells in effusions is associated with poor prognosis. In the present study, we assessed the clinical significance of Rsf-1 overexpression in breast carcinoma effusions. Formalin-fixed paraffin-embedded sections from 47 effusions were analyzed for Rsf-1 expression by immunohistochemistry. Matched primary tumors (n = 30) and solid metastases (n = 26) from 30 patients were additionally studied. Rsf-1 expression in tumor cells in effusions was analyzed for association with clinicopathologic parameters and survival. Rsf-1 protein expression was found in carcinoma cells in 34 (72%) of 47 effusions, 24 (80%) of 30 primary carcinomas, and 24 (92%) of 26 metastases. Rsf-1 immunoreactivity in effusions showed no association with HER-2 or hormone receptor status. Rsf-1 expression level was significantly lower in effusions compared with primary tumors (P = .026 and P = .011 for extent and intensity, respectively) and lymph node metastases (P = .023 and P = .013 for extent and intensity, respectively). Staining extent and intensity were both significantly lower in breast compared with ovarian carcinoma effusions (P = .001 for extent, P < .001 for intensity). Rsf-1 expression showed no association with survival. In conclusion, in contrast to ovarian carcinoma, Rsf-1 expression is down-regulated in breast carcinoma cells in effusions compared with the solid counterparts and has no prognostic role at this anatomic site.

Estrogen insensitivity in a model of estrogen receptor positive breast cancer lymph node metastasis

The lymphatic system is a common avenue for the spread of breast cancer cells and dissemination through it occurs at least as frequently as hematogenous metastasis. Approximately 75% of primary breast cancers are estrogen receptor (ER) positive and the majority of these maintain receptor expression as lymph node (LN) metastases. However, it is unknown if ER function is equivalent in cancer cells growing in the breast and in the LNs. We have developed a model to assess estrogen responsiveness in ER(+) breast tumors and LN metastases. Fluorescent ER(+) MCF-7 tumors were grown in ovariectomized nude mice supplemented with estradiol. Once axillary LN metastasis arose, estradiol was withdrawn (EWD), for 1 or 4 weeks, or continued, to assess estradiol responsiveness. On EWD, proliferation rates fell similarly in tumors and LN metastases. However, estradiol-dependent ER down-regulation and progesterone receptor induction were deficient in LN metastases, indicating that ER-dependent transcriptional function was altered in the LN. Cancer cells from estradiol-treated and EWD primary tumors and matched LN metastases were isolated by laser capture microdissection. Global gene expression profiling identified transcripts that were regulated by the tissue microenvironment, by hormones, or by both. Interestingly, numerous genes that were estradiol regulated in tumors lost estradiol sensitivity or were regulated in the opposite direction by estradiol in LN metastases. We propose that the LN microenvironment alters estradiol signaling and may contribute to local antiestrogen resistance.

Upregulation of EMMPRIN after permanent focal cerebral ischemia

Elevated activities of matrix metalloproteinases (MMPs) following ischemic stroke have been shown to mediate ischemic injury as well as neurovascular remodeling. The extracellular MMP inducer (EMMPRIN) is a 58-kDa cell surface glycoprotein, which has been known to play a key regulatory role for MMP activities. The roles of EMMPRIN in stroke injury are not clearly understood. In this study, we investigated changes of EMMPRIN in a mouse model of permanent focal cerebral ischemia, and examined potential association between EMMPRIN and MMP-9 expression. Adult male CD-1 mice were subjected to permanent focal ischemia by intraluminal occlusion of the left middle cerebral artery (MCAO) under anesthesia. EMMPRIN expression was markedly upregulated in the peri-infarct area at 2-7 days after ischemia compared to the contralateral non-ischemic hemisphere by Western blot analysis. Immunofluorescent double staining demonstrated that EMMPRIN signals co-localized with vwF-positive endothelial cells and GFAP-positive peri-vascular astrocytes. In contrast, EMMPRIN signal did not co-localize with NeuN-positive neurons, or MPO-positive neutrophils. Dual fluorescent staining revealed that EMMPRIN co-localized with MMP-9. Our data also demonstrated that increased EMMPRIN expression correlated with increased MMP-9 levels in a temporal manner. In summary, we report for the first time that EMMPRIN expression was significantly increased in a mouse model of permanent focal cerebral ischemia. The spatial and temporal association between increased EMMPRIN expression and elevated MMP-9 levels suggest that EMMPRIN may modulate MMP-9 activity, and participate in neurovascular remodeling after ischemic stroke.

A gene expression signature associated with metastatic cells in effusions of breast carcinoma patients

Malignant effusion in invasive breast carcinoma is associated with poor prognosis. To decipher molecular events leading to metastasis and to identify reliable markers for targeted therapies are of crucial need. Therefore, we have used cDNA microarrays to delineate molecular signatures associated with metastasis and relapse in breast carcinoma effusions. Taking advantage of an immunomagnetic method, we have purified to homogeneity EpCAM-positive cells from 34 malignant effusions. Immunopurified cells represented as much as 10% of the whole cell fraction and their epithelial and carcinoma features were confirmed by immunofluorescence labeling. Gene expression profiles of 19 immunopurified effusion samples, were analyzed using human pan-genomic microarrays, and compared with those of 4 corresponding primary tumors, 8 breast carcinoma effusion-derived cell lines, and 4 healthy mammary tissues. Principal component and multiple clustering analyses of microarray data, clearly identified distinctive molecular portraits corresponding to the 4 categories of specimens. Of uppermost interest, effusion samples were arranged in 2 subsets on the basis of their gene expression patterns. The first subset partly shares a gene expression signature with the different cell lines, and overexpresses CD24, CD44 and epithelial cytokeratins 8,18,19. The second subset overexpresses markers related to aggressive invasive carcinoma (uPA receptor, S100A4, vimentin, CXCR4). These findings demonstrate the importance of using pure cell fractions to accurately decipher in silico gene expression of clinical specimens. Further studies will lead to the identification of genes of oustanding importance to diagnose malignant effusion, predict survival and tailor appropriate therapies to the metastatic effusion disease in breast carcinoma patients.

Role of nerve growth factor and its receptors in non-nervous cancer growth: efficacy of a tyrosine kinase inhibitor (AG879) and neutralizing antibodies antityrosine kinase receptor A and antinerve growth factor: an in-vitro and in-vivo study

Neurotrophins, originally identified as neuronal survival and differentiation factors, exert their actions through tyrosine kinase receptors such as TrKA, in the case of the nerve growth factor. Neurotrophins also interact with p75, a common receptor devoid of kinase activity and connected to apoptosis. Here we show that nerve growth factor, TrKA and p75 are expressed in cell lines of human cancers of various non-neuronal lineages, including a panel of muscular sarcomas, and we show that all cell lines investigated actively release nerve growth factor into the medium. Treatment by AG879 (a tyrosine kinase inhibitor that inhibits TrKA phosphorylation, but not TrKB and TrKC) or by neutralizing antibodies anti-nerve growth factor and anti-TrKA dramatically decreases their proliferation with a variable increase in apoptosis. Similarly, p75 transfection induced a significant increase in apoptosis. Furthermore, for the first time we have determined by high-performance liquid chromatography the pharmacokinetic profile of a novel preparation of AG879 and we have established an optimal plasmatic concentration for in-vivo administration. Treatment with AG879 in immunodepressed mice grafted with leiomyosarcoma or promyelocytic leukemia cells resulted in dramatic reductions in tumor sizes. In conclusion, our data have a novel preclinical potential for revealing a possible therapeutical utility in targeting in-vivo nerve growth factor/TrKA by AG879 or neutralizing antibody anti-TrKA in cancer proliferation and in muscle sarcomas, in particular.

Expression of Snail, Slug and Sip1 in malignant mesothelioma effusions is associated with matrix metalloproteinase, but not with cadherin expression

Snail, Slug and Sip1 regulate cadherin and protease expression and mediate epithelial-mesenchymal transition in cancer. We analyzed the expression of cadherins and matrix metalloproteinases (MMP) and their transcriptional regulators in malignant mesothelioma (MM). One hundred and ten MM specimens (86 solid, 24 effusions) and 10 non-malignant effusions with reactive mesothelial cells (RMC) were analyzed for E-cadherin, N-cadherin and P-cadherin protein expression using immunhistochemistry. MM effusions were further analyzed for expression of Snail, Slug, Sip1, E-cadherin, MMP-2, MMP-9, MT1-MMP (MMP-14) and the MMP inhibitor TIMP-2, and for MMP-2 and MMP-9 activity using RT-PCR, Western blotting, immunhistochemistry and zymography. Results were analyzed for relationship with specimen type (biopsy versus effusion) and anatomic site (pleural versus peritoneal). E-cadherin, N-cadherin and P-cadherin expression was found in 69/110 (63%), 87/110 (79%) and 84/110 (76%) MM cases, respectively. Pleural and peritoneal MM showed comparable expression, but all three cadherins were upregulated in effusions compared to solid tumors (p<0.001). RMC were uniformly negative for E-cadherin and N-cadherin, and showed P-cadherin expression in 7/10 specimens. Immunohistochemistry localized MMP-2, MMP-9 and TIMP-2 to MM cells in 11/15, 14/15 and 8/15 effusions, respectively. RT-PCR showed direct association between MMP-2 mRNA expression level and the levels of MT1-MMP (p=0.027) and TIMP-2 (p=0.011). Snail protein expression showed positive association with MT1-MMP (p=0.016) and TIMP-2 (p=0.02) mRNA expression, but its expression was unrelated to MMP-2 and MMP-9 expression or activity. Snail, Slug and Sip1 levels did not show inverse association with E-cadherin levels. Our data show that E-cadherin and N-cadherin are selectively expressed in malignant mesothelial cells, and that P-cadherin and N-cadherin are expressed with similar frequency in MM. In agreement with our earlier data for ovarian carcinoma, cadherin expression is upregulated in effusions compared to solid lesions. The increased E-cadherin expression in effusions may be related to lack of negative regulation at the epigenetic level. The relationship between Snail and MMP in MM is uncertain at present.

The metastasis-associated 67-kDa laminin receptor is involved in G-CSF–induced hematopoietic stem cell mobilization

The 67-kDa laminin receptor (67LR) is a nonintegrin cell-surface receptor with high affinity for laminin, which plays a key role in tumor invasion and metastasis. We investigated the role of 67LR in granulocyte colony-stimulating factor (G-CSF)–induced mobilization of CD34+ hematopoietic stem cells (HSCs) from 35 healthy donors. G-CSF–mobilized HSCs, including CD34+/CD38– cells, showed increased 67LR expression as compared with unstimulated marrow HSCs; noteworthy, also, is the fact that the level of 67LR expression in G-CSF–mobilized HSCs correlated significantly with mobilization efficiency. During G-CSF–induced HSC mobilization, the expression of laminin receptors switched from α6 integrins, which mediated laminin-dependent adhesion of steady-state human marrow HSCs, to 67LR, responsible for G-CSF–mobilized HSC adhesion and migration toward laminin. In vitro G-CSF treatment, alone or combined with exposure to marrow-derived endothelial cells, induced 67LR up-regulation in marrow HSCs; moreover, anti-67LR antibodies significantly inhibited transendothelial migration of G-CSF–stimulated marrow HSCs. Finally, G-CSF–induced mobilization in mice was associated with 67LR up-regulation both in circulating and marrow CD34+ cells, and anti-67LR antibodies significantly reduced HSC mobilization, providing the first in vivo evidence for 67LR involvement in stem-cell egress from bone marrow after G-CSF administration. In conclusion, 67LR up-regulation in G-CSF–mobilized HSCs correlates with their successful mobilization and reflects its increase in marrow HSCs, which contributes to the egress from bone marrow by mediating laminin-dependent cell adhesion and transendothelial migration.

Extracellular Matrix Metalloproteinase Inducer (CD147) Confers Resistance of Breast Cancer Cells to Anoikis through Inhibition of Bim

Overexpression of extracellular matrix metalloproteinase inducer (EMMPRIN or CD147), a member of the immunoglobulin family and a glycoprotein enriched on the surface of tumor cells, promotes invasion, metastasis, and growth and survival of malignant cells and confers resistance to some chemotherapeutic drugs. However, the molecular mechanisms underlying the actions of EMMPRIN are not fully understood. In this study we sought to determine whether EMMPRIN contributes to the malignant phenotype of breast cancer by inhibiting anoikis, a form of apoptosis induced by loss or alteration of cell-cell or cell-matrix anchorage, and to explore the signaling pathways involved. We found that in the absence of attachment, human breast carcinoma cells expressing high levels of EMMPRIN formed less compact aggregates with larger surface area and less fibronectin matrix assembly, had higher viability, and were resistant to anoikis. Knockdown of EMMPRIN expression by RNA interference (small interfering RNA or short hairpin RNA) sensitized cancer cells to anoikis, as demonstrated by activation of caspase-3, increased DNA fragmentation, and decreased cellular viability. Furthermore, we observed that the accumulation of Bim, a proapoptotic BH3-only protein, was reduced in EMMPRIN-expressing cells and that silencing of EMMPRIN expression elevated Bim protein levels and enhanced cellular sensitivity to anoikis. Treatment of cells with a MEK inhibitor (U0126) or proteasome inhibitor (epoxomicin) also up-regulated Bim accumulation and rendered cells more sensitive to anoikis. These results indicated that expression of EMMPRIN protects cancer cells from anoikis and that this effect is mediated at least in part by a MAP kinase-dependent reduction of Bim. Because anoikis deficiency is a key feature of neoplastic transformation and invasive growth of epithelial cancer cells, our study on the role of EMMPRIN in anoikis resistance and the mechanism involved underscores the potential of EMMPRIN expression as a prognostic marker and novel target for cancer therapy.

Expression of HLA-G in malignant mesothelioma and clinically aggressive breast carcinoma

The aim of the present study was to evaluate HLA-G expression in breast carcinoma and malignant mesothelioma (MM). Malignant breast carcinoma effusions (46) and corresponding solid tumors (39) and 104 MM (26 effusions, 78 solid tumors) were analyzed using immunohistochemistry (IHC). HLA-G protein and mRNA expression were further studied using immunoblotting (IB) and RT-PCR. HLA-ABC expression was analyzed using flow cytometry (FCM). IHC showed predominantly focal HLA-G expression in 12 of 46 (26%) breast carcinoma effusions and 16 of 39 (41%) solid lesions. In MM, 20 of 78 (26%) solid lesions and 14 of 26 (54%) effusions were focally HLA-G positive. Expression in MM was higher in effusions (p=0.008). IB showed more frequent HLA-G expression in MM compared with breast carcinoma effusions, while RT-PCR showed HLA-G mRNA expression in both tumors. FCM showed conserved HLA-ABC expression in 15 of 15 effusions. Breast cancer patients with HLA-G-positive tumor cells had shorter disease-free survival (mean 37 vs 85, median 25 vs 31 months), though not significantly (p=0.14). In conclusion, HLA-G is focally expressed in MM and breast carcinoma, while HLA-ABC expression is conserved. However, the up-regulated expression of HLA-G in MM effusions and its possible association with shorter disease-free survival in advanced stage of breast carcinoma suggest a possible role in immune response evasion in some tumors.

Tumour microenvironment - opinion: validating matrix metalloproteinases as drug targets and anti-targets for cancer therapy

The matrix metalloproteinases (MMPs) mediate homeostasis of the extracellular environment. They have multiple signalling activities that are commonly altered during tumorigenesis and that might serve as intervention points for anticancer drugs. However, there are many criteria to consider in validating MMPs as drug targets and for the development of MMP inhibitors. The inhibition of some MMPs could have pro-tumorigenic effects (making them anti-targets), counterbalancing the benefits of target inhibition. These effects might partially account for the failure of MMP inhibitors in clinical trials. What are the major challenges in MMP target validation and MMP-inhibitor-drug development?

The mitogen-activated protein kinases (MAPK) p38 and JNK are markers of tumor progression in breast carcinoma

OBJECTIVE

To investigate the activation of mitogen-activated protein kinases (MAPK) in breast carcinoma effusions and to analyze its relationship to anatomic site and clinical parameters.

METHODS

Activated MAPK (p-ERK, p-JNK, and p-p38) expression was studied in 42 effusions and 51 corresponding solid tumors (23 primary, 28 metastases) using immunohistochemistry (IHC). Hormone receptor and HER2 status, proliferation (Ki-67), and apoptosis (p85-PARP fragment) were assessed. MAPK levels, activity, and activation ratio (phospho/pan-MAPK ratio) were analyzed in 19 effusions using immunoblotting (IB).

RESULTS

Nuclear expression of p-p38 and p-JNK was significantly higher in effusions compared with both primary tumors (P < 0.001 for p-JNK, P = 0.011 for p-p38) and lymph node metastases (P = 0.003 for p-JNK, P = 0.025 for p-p38) but was not accompanied by apoptosis. IB showed pan-ERK and p-ERK in 18/19 effusions, pan-JNK and p-JNK in 18/19 and 17/19 effusions, respectively, and pan-p38 and p-p38 in 19/19 and 17/19 specimens, respectively. In univariate survival analysis of all cases, advanced disease stage (P = 0.041), previous chemotherapy (P = 0.004), and radiation (P = 0.001) and higher Ki-67 scores (P = 0.01) correlated with worse overall survival (OS). In Cox multivariate analysis, stage (P = 0.018), chemotherapy (P = 0.024), radiation (P = 0.017), and ER status (P = 0.002) were independent prognosticators of OS. Quantitative analysis of IB data showed that higher p38 activation ratio correlates with shorter OS (P = 0.01).

CONCLUSIONS

This study presents first evidence of in vivo activation of MAPK in breast carcinoma effusions. The elevated JNK and p38 activation in effusions may be a stress-related mechanism providing breast carcinoma cells with survival advantages rather than a drive towards apoptosis. p38 and Ki-67 may be new prognostic markers for patients with breast cancer effusions.

Role of SCC-S2 in experimental metastasis and modulation of VEGFR-2, MMP-1, and MMP-9 expression

SCC-S2/GG2-1/NDED (approved gene symbol TNFAIP8) is a transcription factor NF-kappaB-inducible, antiapoptotic, and oncogenic molecule. In this study, we examined the role of SCC-S2 in invasion and experimental metastasis. We demonstrate that expression of SCC-S2 cDNA in MDA-MB 435 human breast cancer cells is associated with enhanced invasion in vitro and increased frequency of pulmonary colonization of tumor cells in athymic mice. Systemic treatment of athymic mice with a cationic liposomal formulation of SCC-S2 antisense oligo led to decreased incidence of pulmonary metastasis and inhibition of SCC-S2 expression in vivo. Antisense inhibition of endogenous SCC-S2 expression correlated with decreased expression of VEGF receptor-2 in tumor cells and human lung microvascular endothelial cells and loss of endothelial cell viability. In addition, downregulation of SCC-S2 expression in tumor cells was associated with decreased expression of known metastasis-related molecules MMP-1 and MMP-9. These results demonstrate a novel role for SCC-S2 in tumor progression, involving multiple effectors, and provide a basis for SCC-S2-targeted cancer gene therapy.

Angiogenic molecule expression is downregulated in effusions from breast cancer patients

The objective of this study was to analyze site-related expression of angiogenic molecules in breast carcinoma, with the aim of characterizing phenotypic alterations along the clinical progression from primary tumor to pleural effusion. A total of 49 malignant pleural effusions and 68 corresponding solid tumors were studied for protein and mRNA expression of vascular endothelial growth factor (VEGF) and its receptor KDR, interleukin-8 (IL-8), basic fibroblast growth factor (bFGF) and the alphaV integrin subunit using immunohistochemistry, mRNA in situ hybridization (ISH) and reverse transcription polymerase chain reaction (RT-PCR). Expression was analyzed for possible association with mRNA expression of the Ets-1 and PEA3 transcription factors. The predictive value of angiogenic molecules, PEA3 and Ets-1, and clinical parameters was analyzed for 18 patients. ISH showed the presence of VEGF, IL-8 and bFGF mRNA in the majority of specimens, irrespective of anatomic site (p > 0.05). However, protein expression of IL-8 and bFGF was lower in effusions compared to primary tumors (p = 0.001 for IL-8, p < 0.001 for bFGF). Expression of alphaV integrin showed an opposite change, with higher level in effusions compared to primary tumors (p = 0.03). bFGF and alphaV integrin expression in effusions was also altered compared to lymph node metastases (p = 0.041 and p = 0.016, respectively). IL-8 and Ets-1 (p = 0.035) and VEGF and PEA3 (p = 0.026) mRNA was co-expressed in effusions. In univariate survival analysis, bFGF protein expression in effusions (p = 0.015), PEA3 mRNA expression in primary tumors (p = 0.02) and previous radiation therapy (p = 0.034) predicted shorter disease-free survival. PEA mRNA expression in primary tumors (p = 0.002) and previous chemotherapy (p = 0.048) predicted poor overall survival, with a similar trend for advanced disease stage at diagnosis (p = 0.05). Our data provide evidence regarding molecular changes that occur along the progression of breast carcinoma from primary tumor to effusion, and suggest altered requirement of angiogenic factors in body cavities. The poor disease-free survival for patients with bFGF-positive effusions suggests a role for this growth factor in mediating tumor survival rather than angiogenesis at this site.

Microsatellite analysis of pleural supernatants could increase sensitivity of pleural fluid cytology

Pleural effusions may result from various inflammatory, hemodynamic, or neoplastic conditions. A common diagnostic problem lies in distinguishing malignant from benign pleural effusions using routine cytological evaluation. We studied pleural fluid samples obtained from 14 patients with histologically confirmed malignancy and from 6 patients with benign pleural effusions using 12 microsatellite markers from 8 different chromosomal regions. Supernatants and cellular sediments of all 20 pleural fluid samples were analyzed. Routine cytological examination was 100% specific for malignancy but was only 57% sensitive. Microsatellite analyses of pleural fluid supernatants showed genetic alterations in tumor patients only. However, 50% of pleural effusions that were considered negative for malignancy by routine cytological analysis showed either loss of heterozygosity or microsatellite instability. The sensitivity of pleural fluid examination rose to 79% when routine cytological assessment was supplemented by molecular studies. Our data suggest that microsatellite analysis increases the sensitivity of cytological pleural fluid examination in assessing potential malignancy and that combining cytological and molecular methods may improve yield and certainty in diagnostically challenging cases.

Genes that mediate breast cancer metastasis to lung

By means of in vivo selection, transcriptomic analysis, functional verification and clinical validation, here we identify a set of genes that marks and mediates breast cancer metastasis to the lungs. Some of these genes serve dual functions, providing growth advantages both in the primary tumour and in the lung microenvironment. Others contribute to aggressive growth selectively in the lung. Many encode extracellular proteins and are of previously unknown relevance to cancer metastasis.