EpCAM-independent isolation of circulating tumor cells with epithelial-to-mesenchymal transition and cancer stem cell phenotypes using ApoStream® in patients with breast cancer treated with primary systemic therapy.

BACKGROUND: Tumor cells with a mesenchymal phenotype and/or cancer stem-like cells (CSCs) are known to contribute to metastasis and drug resistance. Circulating tumor cells (CTCs) undergoing epithelial-mesenchymal transition (EMT) and CTCs reflecting a dedifferentiated CSC phenotype may not be detected using only an anti-EpCAM antibody to capture them. We used an antibody-independent CTC enrichment platform, ApoStream®, which does not rely on any antibody, including anti-EpCAM, to capture EMT- and CSC-CTCs in breast cancer patients who received neoadjuvant chemotherapy and correlated them to pathological complete response (pCR). METHODS: Blood samples from newly diagnosed breast cancer patients were prospectively collected before neoadjuvant chemotherapy (T0), after chemotherapy but before surgery (T1), and after surgery (T2) and processed using ApoStream. CTCs detected were stained with additional markers to define 3 CTC subsets with the following phenotypes: epithelial CTCs (CK+, EpCAM+ or E-cadherin+), EMT-CTCs (ß-catenin+ or vimentin+), and CSC-CTCs (CD44+ and CD24low). RESULTS: We enrolled 55 patients, 47 of which had data for analysis. EMT-CTCs were detected in 57%, 62%, and 72% and CSC-CTCs in 9%, 22%, and 19% at the T0, T1, and T2 time points, respectively. Counts of epithelial (P = 0.225) and EMT (P = 0.522) phenotypes of CTCs at T0 did not significantly predict pCR. Moreover, no correlation between CTC count change and pCR was demonstrated. CONCLUSIONS: ApoStream was successful in detecting EMT-CTCs among patients after neoadjuvant chemotherapy. However, EMT-/CSC-CTC counts did not correlate with pCR. Due to the small sample size and heterogeneity of this patient population, further study in a larger cohort of molecularly homogeneous patients is warranted.

A phase Ib study of entinostat plus lapatinib with or without trastuzumab in patients with HER2-positive metastatic breast cancer that progressed during trastuzumab treatment.

BACKGROUND: Human epidermal growth factor 2 (HER2) is an effective therapeutic target in breast cancer; however, resistance to anti-HER2 agents such as trastuzumab and lapatinib develops. In a preclinical model, an HDAC inhibitor epigenetically reversed the resistance of cancer cells to trastuzumab and showed synergistic efficacy with lapatinib in inhibiting growth of trastuzumab-resistant HER2-positive (HER2+) breast cancer. METHODS: A phase 1b, dose escalation study was performed to assess maximum tolerated dose, safety/toxicity, clinical efficacy and explored pharmacodynamic biomarkers of response to entinostat combined with lapatinib with or without trastuzumab. RESULTS: The combination was safe. The MTD was lapatinib, 1000 mg daily; entinostat, 12 mg every other week; trastuzumab, 8 mg/kg followed by 6 mg/kg every 3 weeks. Adverse events included diarrhoea (89%), neutropenia (31%), and thrombocytopenia (23%). Neutropenia, thrombocytopenia and hypokalaemia were noted. Pharmacodynamic assessment did not yield conclusive results. Among 35 patients with evaluable response, PR was observed in 3 patients and CR in 3 patients, 1 maintained SD for over 6 months. DISCUSSION: This study identified the MTD of the entinostat, lapatinib, and trastuzumab combination that provided acceptable tolerability and anti-tumour activity in heavily pre-treated patients with HER2+ metastatic breast cancer, supporting a confirmatory trial.

Change in Topoisomerase 1-Positive Circulating Tumor Cells Affects Overall Survival in Patients with Advanced Breast Cancer after Treatment with Etirinotecan Pegol.

Purpose: Preplanned exploratory analyses were performed to identify biomarkers in circulating tumor cells (CTC) predictive of response to the topoisomerase 1 inhibitor etirinotecan pegol (EP).Experimental Design: The BEACON trial treated patients with metastatic breast cancer (MBC) with EP or treatment of physician's choice (TPC). Blood from 656 of 852 patients (77%) was processed with ApoStream to enrich for CTCs. A multiplex immunofluorescence assay measured expression of candidate response biomarkers [topoisomerase 1 (Top1), topoisomerase 2 (Top2), Ki67, RAD51, ABCG2, γH2AX, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)] in CTCs. Patients were classified as Top1 low (Top1Lo) or Top1 high (Top1Hi) based on median CTC Top1 expression. Correlation of CTC biomarker expression at baseline, cycle 2 day 1 (C2D1), and cycle 4 day 1 with overall survival (OS) was investigated using Cox regression and Kaplan-Meier analyses.Results: Overall, 98% of samples were successfully processed, of which 97% had detectable CTCs (median, 47-63 CTCs/mL; range, 0-2,020 CTCs/mL). Top1, Top2, and TUNEL expression was detected in 52% to 90% of samples; no significant associations with OS were observed in pretreatment samples for either group. EP-treated patients with low C2D1Top1+ CTCs had improved OS compared with those with higher positivity (14.1 months vs. 11.0 months, respectively; HR, 0.7; P = 0.02); this difference was not seen in TPC-treated patients (HR, 1.12; P = 0.48). Patients whose CTCs decreased from Top1Hi to Top1Lo at C2D1 had the greatest OS benefit from EP (HR, 0.57; P = 0.01).Conclusions: CTC Top1 expression following EP treatment may identify patients with MBC most likely to have an OS benefit. Clin Cancer Res; 24(14); 3348-57. ©2018 AACR.

Antibody-independent capture of circulating tumor cells of non-epithelial origin with the ApoStream® system.

Circulating tumor cells (CTCs) are increasingly employed for research and clinical monitoring of cancer, though most current methods do not permit the isolation of non-epithelial tumor cells. Furthermore, CTCs isolated with antibody-dependent methods are not suitable for downstream experimental uses, including in vitro culturing and implantation in vivo. In the present study, we describe the development, validation, and transfer across laboratories of a new antibody-independent device for the enrichment of CTCs from blood samples of patients with various cancer diagnoses. The ApoStream® device uses dielectrophoresis (DEP) field-flow assist to separate non-hematopoietic cells from the peripheral blood mononuclear fraction by exposing cells in a laminar flow stream to a critical alternating current frequency. The ApoStream® device was calibrated and validated in a formal cross-laboratory protocol using 3 different cancer cell lines spanning a range of distinct phenotypes (A549, MDA-MB-231, and ASPS-1). In spike-recovery experiments, cancer cell recovery efficiencies appeared independent of spiking level and averaged between 68% and 55%, depending on the cell line. No inter-run carryover was detected in control samples. Moreover, the clinical-readiness of the device in the context of non-epithelial cancers was evaluated with blood specimens from fifteen patients with metastatic sarcoma. The ApoStream® device successfully isolated CTCs from all patients with sarcomas examined, and the phenotypic heterogeneity of the enriched cells was demonstrated by fluorescence in situ hybridization or with multiplex immunophenotyping panels. Therefore, the ApoStream® technology expands the clinical utility of CTC evaluation to mesenchymal cancers.

Isolation of Circulating Tumor Cells from Multiple Epithelial Cancers with ApoStream(®) for Detecting (or Monitoring) the Expression of Folate Receptor Alpha.

This study describes our efforts to further the field of noninvasive diagnostics, specifically in the area of liquid biopsies in oncology. We employed laser scanning cytometry using highly selective antibodies to interrogate circulating tumor cells (CTCs) that were isolated using ApoStream(®) technology to identify folate receptor alpha (FRα)-positive cells. We demonstrate that FRα(+) CTCs can be isolated from patients with metastatic cancers, including NSCLC adenocarcinoma, breast cancer, and ovarian cancer, whereas squamous cell lung cancer and normal healthy controls were devoid of FRα(+) CTCs. We believe that the developed methodology will have applications in both the diagnosis and the monitoring of FRα-expressing cancers. Folate receptor alpha (FRα) expression may have utility as a potential diagnostic and therapeutic target in solid tumors. As tissue samples are not always available for patient screening, this study evaluated a noninvasive assay in CTCs from blood samples to detect FRα expression. The presence of FRα(+) CTCs enriched using ApoStream(®) and detected using laser capture cytometry was evaluated in blood samples from cancer patients [NSCLC adenocarcinoma (n = 14), breast cancer (n = 20), ovarian cancer (n = 6), and squamous lung cancer patients (n = 6)] and healthy subjects (n = 20). The data demonstrated that FRα(+) CTCs were detected in blood from NSCLC adenocarcinoma, breast, and ovarian cancer patients, whereas squamous cell lung cancer patients and normal healthy controls lacked FRα(+) CTCs as previously known. We demonstrate that CTCs captured using ApoStream(®) can be used to detect FRα(+) CTCs and may have clinical utility as a real-time liquid biopsy for assessing FRα levels in cancer patients.

Topology-function conservation in protein-protein interaction networks.

MOTIVATION: Proteins underlay the functioning of a cell and the wiring of proteins in protein-protein interaction network (PIN) relates to their biological functions. Proteins with similar wiring in the PIN (topology around them) have been shown to have similar functions. This property has been successfully exploited for predicting protein functions. Topological similarity is also used to guide network alignment algorithms that find similarly wired proteins between PINs of different species; these similarities are used to transfer annotation across PINs, e.g. from model organisms to human. To refine these functional predictions and annotation transfers, we need to gain insight into the variability of the topology-function relationships. For example, a function may be significantly associated with specific topologies, while another function may be weakly associated with several different topologies. Also, the topology-function relationships may differ between different species. RESULTS: To improve our understanding of topology-function relationships and of their conservation among species, we develop a statistical framework that is built upon canonical correlation analysis. Using the graphlet degrees to represent the wiring around proteins in PINs and gene ontology (GO) annotations to describe their functions, our framework: (i) characterizes statistically significant topology-function relationships in a given species, and (ii) uncovers the functions that have conserved topology in PINs of different species, which we term topologically orthologous functions. We apply our framework to PINs of yeast and human, identifying seven biological process and two cellular component GO terms to be topologically orthologous for the two organisms.

Dual inhibition of the vascular endothelial growth factor pathway: a phase 1 trial evaluating bevacizumab and AZD2171 (cediranib) in patients with advanced solid tumors.

BACKGROUND: The current study was conducted to evaluate the safety and biological activity of dual inhibition of the vascular endothelial growth factor (VEGF) pathway with combined bevacizumab and cediranib (a VEGF receptor tyrosine kinase inhibitor). METHODS: This was a 3 + 3 dose escalation study in patients with advanced solid tumors. Cediranib was given orally daily for 21 days and bevacizumab intravenously every 2 weeks. Pharmacokinetics and correlates (nitric oxide synthase, nitrate oxide, and circulating tumor cells) were assessed. RESULTS: Fifty-one patients were treated. Dose-limiting toxicities (DLTs) (grade 3-4; graded according to the National Cancer Institute Common Terminology Criteria of Adverse Events [version 3.0]) observed included 1 patient with chest pain, 1 patient with fatigue, 2 patients with thrombocytopenia, 3 patients with hypertension (1 with intracranial hemorrhage), and 1 patient with grade 5 hemoptysis. Moreover, 2 patients presented with grade 3 intracranial bleeding beyond the DLT window. Dose level 2 (cediranib at a dose of 20 mg/day and bevacizumab at a dose of 5 mg/kg every 2 weeks) was selected as the recommended phase 2 dose (RP2D); 17 patients were treated at dose level 2 with 1 DLT and no intracranial bleeding or severe hypertension reported. Pharmacokinetics of cediranib at dose level 3 demonstrated a 46% to 77% increase in area under the curve (0-24 hours) on cycle 1 day 1 compared with historical controls. Four patients attained partial remissions: inflammatory breast cancer (-54%), basal cell carcinoma (-33%), alveolar soft part sarcoma (-33%), and synovial sarcoma (-32%). Patients with a lower circulating tumor cell count (< 30) at the predose period had a longer time to tumor progression (P = .024, log-rank test). CONCLUSIONS: Cediranib at a dose of 20 mg/day and bevacizumab at a dose of 5 mg/kg every 2 weeks was found to be the RP2D. Activity in several tumor types was noted. Central nervous system bleeding and severe hypertension were observed at doses above the RP2D.

Revealing the hidden language of complex networks.

Sophisticated methods for analysing complex networks promise to be of great benefit to almost all scientific disciplines, yet they elude us. In this work, we make fundamental methodological advances to rectify this. We discover that the interaction between a small number of roles, played by nodes in a network, can characterize a network's structure and also provide a clear real-world interpretation. Given this insight, we develop a framework for analysing and comparing networks, which outperforms all existing ones. We demonstrate its strength by uncovering novel relationships between seemingly unrelated networks, such as Facebook, metabolic, and protein structure networks. We also use it to track the dynamics of the world trade network, showing that a country's role of a broker between non-trading countries indicates economic prosperity, whereas peripheral roles are associated with poverty. This result, though intuitive, has escaped all existing frameworks. Finally, our approach translates network topology into everyday language, bringing network analysis closer to domain scientists.

Epithelial cell adhesion molecule-positive circulating tumor cells as predictive biomarker in patients with prostate cancer.

OBJECTIVE: To assess the use of circulating tumor cells (CTCs) as a longitudinal endpoint factor for clinical monitoring of patients with prostate cancer and to evaluate the association among the baseline CTC number, various clinical characteristics, and survival. MATERIALS AND METHODS: The CTCs were enumerated using the CellSearch Food and Drug Administration-cleared CTC kit in 202 patients with prostate cancer. Variables, including metastatic site, prostate-specific antigen level, Gleason score, testosterone level, and use of androgen treatment, were tested for association with the CTC number. The probability of patient survival over time was estimated using the Kaplan-Meier method. RESULTS: The baseline CTC numbers were strongly associated with survival (P <.0001), with overall survival significantly poorer in patients with ≥5 CTCs. Significantly greater CTC numbers were observed in patients with bone metastasis (mean 41.12 CTCs) than in those with lymph node metastasis (mean 2.53 CTC, P = .026). Analysis of the association between the CTC count and prostate-specific antigen level revealed a weak positive correlation (correlation coefficient r = 0.2695, P = .0007). The CTC number also correlated with the Gleason score (P = .0138) and lower testosterone level (P <.0001). Patients without androgen depletion had significantly lower CTC numbers (mean 2.70) than those with androgen depletion (mean 26.39, P <.0001). CONCLUSION: The baseline CTC counts were predictive of patient survival and correlated significantly with the clinical characteristics of patients with prostate cancer. Our study results have confirmed previous findings that support the use of CTC enumeration as a prognostic biomarker for patients with prostate cancer.

A phase II study of lapatinib in recurrent/metastatic squamous cell carcinoma of the head and neck.

PURPOSE: This study sought to determine the efficacy and safety profile of lapatinib in patients with recurrent/metastatic squamous cell carcinoma of the head and neck (SCCHN). EXPERIMENTAL DESIGN: This phase II multiinstitutional study enrolled patients with recurrent/metastatic SCCHN into two cohorts: those without (arm A) and those with (arm B) before exposure to an epidermal growth factor receptor (EGFR) inhibitor. All subjects were treated with lapatinib 1,500 mg daily. Primary endpoints were response rate (arm A) and progression-free survival (PFS; arm B). The biologic effects of lapatinib on tumor growth and survival pathways were assessed in paired tumor biopsies obtained before and after therapy. RESULTS: Forty-five patients were enrolled, 27 in arm A and 18 in arm B. Diarrhea was the most frequent toxicity occurring in 49% of patients. Seven patients experienced related grade 3 toxicity (3 fatigue, 2 hyponatremia, 1 vomiting, and 1 diarrhea). In an intent-to-treat analysis, no complete or partial responses were observed, and stable disease was the best response observed in 41% of arm A (median duration, 50 days, range, 34-159) and 17% of arm B subjects (median, 163 days, range, 135-195). Median PFS was 52 days in both arms. Median OS was 288 (95% CI, 62-374) and 155 (95% CI, 75-242) days for arms A and B, respectively. Correlative analyses revealed an absence of EGFR inhibition in tumor tissue. CONCLUSION: Lapatinib as a single agent in recurrent/metastatic SCCHN, although well tolerated, appears to be inactive in either EGFR inhibitor naive or refractory subjects.

ApoStream(™), a new dielectrophoretic device for antibody independent isolation and recovery of viable cancer cells from blood.

Isolation and enumeration of circulating tumor cells (CTCs) are used to monitor metastatic disease progression and guide cancer therapy. However, currently available technologies are limited to cells expressing specific cell surface markers, such as epithelial cell adhesion molecule (EpCAM) or have limited specificity because they are based on cell size alone. We developed a device, ApoStream(™) that overcomes these limitations by exploiting differences in the biophysical characteristics between cancer cells and normal, healthy blood cells to capture CTCs using dielectrophoretic technology in a microfluidic flow chamber. Further, the system overcomes throughput limitations by operating in continuous mode for efficient isolation and enrichment of CTCs from blood. The performance of the device was optimized using a design of experiment approach for key operating parameters such as frequency, voltage and flow rates, and buffer formulations. Cell spiking studies were conducted using SKOV3 or MDA-MB-231 cell lines that have a high and low expression level of EpCAM, respectively, to demonstrate linearity and precision of recovery independent of EpCAM receptor levels. The average recovery of SKOV3 and MDA-MB-231 cancer cells spiked into approximately 12 × 10(6) peripheral blood mononuclear cells obtained from 7.5 ml normal human donor blood was 75.4% ± 3.1% (n = 12) and 71.2% ± 1.6% (n = 6), respectively. The intra-day and inter-day precision coefficients of variation of the device were both less than 3%. Linear regression analysis yielded a correlation coefficient (R(2)) of more than 0.99 for a spiking range of 4-2600 cells. The viability of MDA-MB-231 cancer cells captured with ApoStream was greater than 97.1% and there was no difference in cell growth up to 7 days in culture compared to controls. The ApoStream device demonstrated high precision and linearity of recovery of viable cancer cells independent of their EpCAM expression level. Isolation and enrichment of viable cancer cells from ApoStream enables molecular characterization of CTCs from a wide range of cancer types.

Inhibition of the mammalian target of rapamycin (mTOR) in advanced pancreatic cancer: results of two phase II studies.

BACKGROUND: The phosphoinositide 3-kinase (PI3K)/Akt pathway is constitutively activated in pancreatic cancer and the mammalian target of rapamycin (mTOR) kinase is an important mediator for its signaling. Our recent in vitro studies suggest that prolonged exposure of pancreatic cancer cells to mTOR inhibitors can promote insulin receptor substrate-PI3K interactions and paradoxically increase Akt phosphorylation and cyclin D1 expression in pancreatic cancer cells (negative feedback loop). The addition of erlotinib to rapamycin can down-regulate rapamycin-stimulated Akt and results in synergistic antitumor activity with erlotinib in preclinical tumor models. METHODS: Two studies prospectively enrolled adult patients with advanced pancreatic cancer, Eastern Cooperative Oncology Group performance status 0-1, adequate hematologic, hepatic and renal parameters and measurable disease. In Study A, temsirolimus was administered intravenously at 25 mg weekly. In Study B, everolimus was administered orally at 30 mg weekly and erlotinib was administered at 150 mg daily. The primary endpoint in both studies was overall survival at 6 months. Secondary endpoints included time to progression, progression-free survival, overall survival, response rate, safety and toxicity. Pretreatment tumor biopsies were analyzed by immunofluorescence and laser scanning cytometry for the expression of pmTOR/mTOR, pAkt/Akt, pErk/Erk, pS6, p4EBP-1 and PTEN. RESULTS: Five patients enrolled in Study A; Two patients died within a month (rapid disease progression and hemorrhagic stroke, respectively). One patient developed dehydration and another developed asthenia. Sixteen patients enrolled in Study B.: 12 males, all ECOG PS = 1. Median cycles = 1 (range 1-2). Grade 4 toxicity: hyponatremia (n = 1), Grade 3: diarrhea (n = 1), cholangitis (n = 3), hyperglycemia (n = 1), fatigue (n = 1). Grade 2: pneumonia (n = 2), dehydration (n = 2), nausea (n = 2), neutropenia (n = 1), mucositis (n = 2) & rash (n = 2). Four patients were hospitalized. Progressive disease occurred in 15 and 1 was non-evaluable. Pretreatment biopsies revealed a higher pAkt/Akt ratio in tumor specimens that in nonmalignant pancreatic tissue. No such trends were noted for the other biomarkers. CONCLUSIONS: Neither study with mTOR inhibitors demonstrated objective responses or disease stability. The negative feedback loop resulting from mTOR inhibition may account for the disease progression and toxicity noted in these studies. Future strategies should aim for a broader targeting of the PI3K pathway in pancreatic cancer. STUDY A: NCT 0075647. STUDY B: NCT00640978.

Erlotinib and bevacizumab in patients with recurrent or metastatic squamous-cell carcinoma of the head and neck: a phase I/II study.

BACKGROUND: Epidermal growth factor receptor (EGFR) is a validated target in squamous-cell carcinoma of the head and neck, but in patients with recurrent or metastatic disease, EGFR targeting agents have displayed modest efficacy. Vascular endothelial growth factor (VEGF)-mediated angiogenesis has been implicated as a mechanism of resistance to anti-EGFR therapy. In this multi-institutional phase I/II study we combined an EGFR inhibitor, erlotinib, with an anti-VEGF antibody, bevacizumab. METHODS: Between April 15, 2003, and Jan 27, 2005, patients with recurrent or metastatic squamous-cell carcinoma of the head and neck were enrolled from seven centres in the USA and were given erlotinib (150 mg daily) and bevacizumab in escalating dose cohorts. The primary objectives in the phase I and II sections, respectively, were to establish the maximum tolerated dose and dose-limiting toxicity of bevacizumab when administered with erlotinib and to establish the proportion of objective responses and time to disease progression. Pretreatment serum and tissues were collected and analysed by enzyme-linked immunosorbent assay and immunofluorescence quantitative laser analysis, respectively. This study was registered with ClinicalTrials.gov, number NCT00055913. FINDINGS: In the phase I section of the trial, ten patients were enrolled in three successive cohorts with no dose-limiting toxic effects noted. 46 patients were enrolled in the phase II section of the trial (including three patients from the phase I section) on the highest dose of bevacizumab (15 mg/kg every 3 weeks). Two additional patients were accrued beyond the protocol-stipulated 46, leaving a total of 48 patients for the phase II assessment. The most common toxic effects of any grade were rash and diarrhoea (41 and 16 of 48 patients, respectively). Three patients had serious bleeding events of grade 3 or higher. Seven patients had a response, with four showing a complete response allowing rejection of the null hypothesis. Median time of overall survival and progression-free survival (PFS) were 7.1 months (95% CI 5.7-9.0) and 4.1 months (2.8-4.4), respectively. Higher ratios of tumour-cell phosphorylated VEGF receptor-2 (pVEGFR2) over total VEGFR2 and endothelial-cell pEGFR over total EGFR in pretreatment biopsies were associated with complete response (0.704 vs 0.386, p=0.036 and 0.949 vs 0.332, p=0.036, respectively) and tumour shrinkage (p=0.007 and p=0.008, respectively) in a subset of 11 patients with available tissue. INTERPRETATION: The combination of erlotinib and bevacizumab is well tolerated in recurrent or metastatic squamous-cell carcinoma of the head and neck. A few patients seem to derive a sustained benefit and complete responses were associated with expression of putative targets in pretreatment tumour tissue.

Cardiac tissue factor: roles in physiology and fibrosis.

1. The aim of the present review is to discuss: (i) the role of tissue factor (TF) in the heart and focus on its potential role in maintaining normal extracellular cardiac homeostasis; (ii) the means by which TF may be contributing to extracellular matrix regulation and vascular maintenance; and (iii) potential mechanisms whereby reduced TF expression leads to cardiac fibrosis. 2. Tissue factor is the main initiator of the coagulation cascade in response to tissue injury, but it is also involved in numerous other biological processes, including angiogenesis, cell migration, apoptosis, metastasis and inflammation. 3. Tissue factor is implicated in cardiovascular disease and its localization and level of expression in cardiomyocytes suggests a unique role in maintaining the structure and function of cardiac muscle. 4. It has been shown that TF(-/-) mice die in utero as a result of disrupted yolk sac vasculature. Low-TF mice, which have transgenic expression of TF at less than 1% of normal levels, are rescued from lethality. 5. Low-TF mice develop cardiac fibrosis in a gender-dependent manner that may be dependent on differential expression of urokinase plasminogen activator. 6. Intracardiac bleeding in low-TF mice may occur as a result of a primary haemostasis defect and/or as a result of disrupted vascular maintenance. The mechanism, when elucidated, will have important therapeutic implications and may provide novel strategies for the treatment of cardiac fibrosis.

The development of cardiac fibrosis in low tissue factor mice is gender-dependent and is associated with differential regulation of urokinase plasminogen activator.

Tissue factor (TF) initiates the protease coagulation cascade in response to tissue injury. Homozygous deficiency of murine TF results in embryonic lethality, which is rescued by low-level expression of human TF. These low-TF mice have been shown to develop cardiac fibrosis. We tested the hypothesis that the development of cardiac fibrosis in low-TF mice results from dysregulated protease expression and is affected by gender. Mice were divided into the age groups 2-5, 6-12, 13-18 and 19+ weeks. Fibrosis was assessed by trichrome staining. Protease expression was measured in male and female mice by RT-PCR for mRNA and zymography, ELISA or immunoblot for protein. Urokinase plasminogen activator (uPA) activity was determined by zymography and chromogenic substrate assay. A marked gender effect was noted for the development of fibrosis, with interstitial collagen deposition occurring from 9 weeks in male low-TF mice, but not until 19 weeks in low-TF females. This delayed onset in females was accompanied by delayed up-regulation of molecular markers of injury. Matrix metalloproteinase (MMP)-3 and tissue inhibitor of metalloproteinase (TIMP)-1 expression were up-regulated in the hearts of male low-TF mice from 6 to 12 weeks and in females from 19 weeks. MMP/TIMP dysregulation was not seen prior to cardiac fibrosis and did not appear to explain the gender differences. However, uPA expression and activity were down-regulated prior to cardiac fibrosis in low-TF females, but were up-regulated in age-matched males. This suggests that the down-regulation of uPA in female low-TF mice protects them from more severe cardiac fibrosis.

Quantitative analysis of melanocytic tissue array reveals inverse correlation between activator protein-2alpha and protease-activated receptor-1 expression during melanoma progression.

The identification of molecular markers of melanoma progression is needed to more accurately stage and identify treatments for patients with malignant melanoma. Previously, we demonstrated that loss of the activator protein-2alpha (AP-2alpha) expression results in overexpression of the protease-activated receptor-1 (PAR-1) in human melanoma cell lines. Here, we used a tissue microarray platform that consisted of 64 melanocytic lesions, including dysplastic nevi (N=21), primary melanoma (N=20), and metastatic melanoma (N=23). We analyzed the expression of AP-2 and PAR-1 simultaneously by immunofluorescent microscopy with an automated quantification laser scanning cytometer. AP-2 was highly expressed in normal cutaneous melanocytes and dysplastic nevi but not in melanoma metastases. We observed a significantly higher number of AP-2-positive cells in the dysplastic nevi (P=0.0013) and primary melanoma (P=0.0023) compared to the metastatic melanoma. In contrast, we observed a significantly higher percentage of PAR-1-positive cells in the metastatic melanoma compared to dysplastic nevi (P=0.0072) and primary melanoma (P=0.0138). Increased expression of PAR-1 in metastatic melanomas contributes to tumor progression by modulating expression of genes, such as IL-8, matrix metalloproteinase-2, vascular endothelial growth factor, platelet-derived growth factor, and integrins. These findings support our hypothesis that loss of AP-2 is a crucial event in the progression of human melanoma and contributes to the acquisition of the metastatic phenotype via upregulation of PAR-1.

Tissue factor deficiency and PAR-1 deficiency are protective against renal ischemia reperfusion injury.

Ischemia/reperfusion (IR) injury is a leading cause of acute renal failure and an important contributor to allograft damage. Tissue factor (TF) is up-regulated during IR, and TF inhibition reduces renal injury. However, the underlying mechanisms by which TF contributes to injury have not been elucidated. We postulated that TF contributes to IR injury by production of coagulation proteases and subsequent signaling by protease activated receptor (PARs). We compared renal injury after 25 minutes of bilateral renal ischemia and varying periods of reperfusion in C57BL/6 mice, those expressing low levels of TF (low-TF), hirudin-treated C57BL/6, and mice lacking either PAR-1 or PAR-2. C57BL/6 mice developed severe renal failure and died within 48 hours of reperfusion. In contrast, low-TF, hirudin-treated C57BL/6, and PAR-1-/- mice were protected from renal failure and had reduced mortality, tubular injury, neutrophil accumulation, and lower levels of the chemokines KC and MIP-2. Importantly, PAR-1-/- mice had lower chemokine levels despite up-regulation of TF and fibrin deposition. In addition, treating PAR-1-/- mice with hirudin conferred no additional benefit. Somewhat surprisingly, PAR-2 deficiency did not protect from renal failure. These experiments indicate that increased TF activity after renal IR leads to increased CXC chemokine expression and subsequent neutrophil-mediated injury predominantly by thrombin-dependent PAR-1 signaling.

Automated quantitative analysis of activator protein-2alpha subcellular expression in melanoma tissue microarrays correlates with survival prediction.

The activator protein-2alpha (AP-2) transcription factor plays a key role in regulating expression of genes involved in tumor growth and metastasis of human melanoma. We sought to assess the prognostic significance of AP-2 expression and its role in the transition of nevi to metastatic melanoma. Two cohorts were analyzed. One was a "progression" microarray containing melanoma specimens from M.D. Anderson Cancer Center representing 84 cases and the other was a retrospective cohort from Yale University representing 214 primary melanomas and 293 metastases. Analysis of total AP-2 expression using two quantitative systems [automated quantitative analysis (AQUA) and laser scanning cytometry (LSC)] revealed no correlation with diagnosis group. LSC analysis of the M.D. Anderson Cancer Center array showed that the number of cells expressing nuclear AP-2 was highest in the benign nevi group (11.85%) and significantly decreased in each phase of melanoma progression to 0.39% in the metastatic group. Both LSC and AQUA showed decreased nuclear AP-2 levels and increased cytoplasmic AP-2 that is directly proportional to progression. Neither nuclear nor cytoplasmic expression levels correlated with outcome. Intriguingly, the ratio of cytoplasmic to nuclear AP-2 predicted outcome in the entire population and in the primary tumors alone, demonstrating the power of the ratio to normalize for variations. Furthermore, the AP-2 ratio directly correlated with other clinicopathologic factors, including Breslow depth (R = 0.334, P < 0.001). We show that a high level of AP-2 expression in the cytoplasm relative to the nucleus correlates with poor prognosis and the loss of nuclear AP-2 expression is associated with malignant transformation and progression of melanoma.

The vascular-targeting fusion toxin VEGF121/rGel inhibits the growth of orthotopic human bladder carcinoma tumors.

Vascular endothelial growth factor (VEGF) and its receptors (FLT-1 and KDR) are overexpressed by human bladder cancer cells and tumor endothelial cells, respectively. Strategies that target VEGF receptors hold promise as antiangiogenic therapeutic approaches to bladder cancer. A fusion protein of VEGF121 and the plant toxin gelonin (rGel) was constructed, expressed in bacteria, and purified to homogeneity. Cytotoxicity experiments of VEGF121/rGel on the highly metastatic 253J B-V human bladder cancer cell line demonstrated that the VEGF121/rGel does not specifically target these cells, whereas Western blot analysis showed no detectable expression of KDR. Treatment with VEGF121/rGel against orthotopically implanted 253J B-V xenografts in nude mice resulted in a significant suppression of bladder tumor growth (approximately 60% inhibition; P < .05) compared to controls. Immunohistochemistry studies of orthotopic 253J B-V tumors demonstrated that KDR is highly overexpressed in tumor vasculature. Immunofluorescence staining with antibodies to CD-31 (blood vessel endothelium) and rGel demonstrated a dramatic colocalization of the construct on tumor neovasculature. Treated tumors also displayed an increase in terminal deoxynucleotidyl transferase-mediated dUTP-biotin end labeling staining compared to controls. Thus, VEGF121/rGel inhibits the growth of human bladder cancer by cytotoxic effects directed against the tumor vascular supply and has significant potential as a novel antiangiogenic therapeutic against human bladder cancer.