Urinary TIMP-1 and MMP-2 levels detect the presence of pancreatic malignancies

Background:

A majority of patients with pancreatic malignancies, including both pancreatic ductal adenocarcinoma (PDAC) and pancreatic neuroendocrine tumours (pNETs), present with advanced disease due to a lack of specific symptoms and current diagnostic limitations, making this disease extremely difficult to detect. Our goal was to determine whether urinary matrix metalloproteases (uMMPs) and/or their endogenous inhibitors, urinary tissue inhibitor of metalloproteases (uTIMPs), could be detected in the urine of patients with pancreatic malignancies and whether they may serve as independent predictors of disease status.

Methods:

Retrospective analyses of urine samples (n=139) from PDAC and pNET patients as well as age- and sex-matched controls were conducted. Urinary MMP-2 and uTIMP-1 levels were determined using ELISA and zymography. Biomarker expression in tumour and normal pancreatic tissues was analysed via immunohistochemistry (IHC).

Results:

Multivariable logistic regression analyses indicated that, when controlling for age and sex, uMMP-2 (P<0.0001) and uTIMP-1 (P<0.0001) but not uMMP-9, were significant independent predictors for distinguishing between PDAC patients and healthy controls. Our data also indicated that uMMP-2 was an independent predictor of the presence of pNET. In addition, uTIMP-1 levels could differentiate the two cancer groups, PDAC and pNET, respectively. Immunohistochemistry analysis confirmed that MMP-2 and TIMP-1 protein expression is significantly upregulated in PDAC tissue compared with the normal pancreas.

Conclusions:

Taken together, our results suggest that the detection of uMMP-2 and uTIMP-1 may have diagnostic value in the detection of pancreatic malignancies and that uTIMP-1 may be useful in distinguishing between pancreatic adenocarcinoma and neuroendocrine tumours.

Matrilin-1 is an inhibitor of neovascularization

In the course of conducting a series of studies whose goal was to discover novel endogenous angiogenesis inhibitors, we have purified matrilin-1 (MATN-1) and have demonstrated, for the first time, that it inhibits neovascularization both in vitro and in vivo. Proteins were extracted from cartilage using a 2 m NaCl, 0.01 m HEPES buffer at 4 °C, followed by concentration of the extract. The concentrate was fractionated by size exclusion chromatography, and fractions were then screened for their ability to inhibit capillary endothelial cell (EC) proliferation in vitro. Fractions containing EC inhibitory activity were pooled and further purified by cation exchange chromatography. The resulting fractions from this step were then screened to isolate the antiangiogenic activity in vitro. This activity was identified by tandem mass spectrometry as being MATN-1. Human MATN-1 was cloned and expressed in Pichia pastoris and purified to homogeneity. Purified recombinant MATN-1, along with purified native protein, was shown to inhibit angiogenesis in vivo using the chick chorioallantoic membrane assay by the inhibition of capillary EC proliferation and migration. Finally, using a MATN-1-deficient mouse, we showed that angiogenesis during fracture healing was significantly higher in MATN-1(-/-) mice compared with the wild type mice as demonstrated by in vivo imaging and by elevated expression of angiogenesis markers including PECAM1, VEGFR, and VE-cadherin.

Inhibiting metastatic breast cancer cell migration via the synergy of targeted, pH-triggered siRNA delivery and chemokine axis blockade

Because breast cancer patient survival inversely correlates with metastasis, we engineered vehicles to inhibit both the C-X-C chemokine receptor type 4 (CXCR4) and lipocalin-2 (Lcn2) mediated migratory pathways. pH-responsive liposomes were designed to protect and trigger the release of Lcn2 siRNA. Liposomes were modified with anti-CXCR4 antibodies to target metastatic breast cancer (MBC) cells and block migration along the CXCR4-CXCL12 axis. This synergistic approach--coupling the CXCR4 axis blockade with Lcn2 silencing--significantly reduced migration in triple-negative human breast cancer cells (88% for MDA-MB-436 and 92% for MDA-MB-231). The results suggested that drug delivery vehicles engineered to attack multiple migratory pathways may effectively slow progression of MBC.

Urine vascular biomarkers in Sturge-Weber syndrome

Sturge-Weber syndrome (SWS) consists of a capillary-venous vascular malformation of the brain, skin and eye. Urine vascular biomarkers have been demonstrated to be abnormal in other vascular anomalies and to correlate with clinical severity and progression. The current study investigated the use of urinary matrix metalloproteinase (MMP)-2, MMP-9, vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) levels to non-invasively monitor the progression of SWS. Fifty-four urine samples were collected from patients seen at the Hunter Nelson Sturge-Weber Center at Kennedy Krieger Institute. Urine was analyzed for MMP-2, MMP-9, VEGF and bFGF levels and correlated with clinical outcome at the time of urine collection (n = 48) and 1 year following urine collection (n = 22). Analysis revealed that MMP-2 (p = 0.033) and MMP-9 (p = 0.010) were significantly more likely to be present in the urine of SWS subjects compared to controls and that bFGF was significantly more likely to be present at abnormal levels (p = 0.005). MMP-2 correlated with a more severe clinical score at the time of urine collection, while both MMP-2 and MMP-9 levels correlated with greater disease severity at time of collection. bFGF levels correlated with improved clinical score 1 year after urine collection. These results suggest that MMP-2 and MMP-9 levels may be useful in assessing SWS progression, as well as indicating which patients might benefit from more aggressive treatment, while bFGF levels may be useful in judging the efficacy of neurologic treatment in SWS.

Abstract A49: Adipocytes promote ovarian cancer cell chemoresistance

Ovarian cancer is the most lethal cancer of the female reproductive system and the fifth leading cause of cancer death among women. One of the reasons for the high death rate among women with ovarian cancer is the resistance to chemotherapy. The majority of the ovarian cancer patients who show an initial response to chemotherapy will succumb to resistance and cancer recurrence. Previous studies have demonstrated that abdominal omental adipocytes promote local ovarian cancer metastasis by attracting cancer cells and acting as an energy source for their growth. However, it is not known whether adipocytes have any effects on the sensitivity of ovarian cancer cells to chemotherapeutic drugs. To address this question, we treated human ovarian cancer cells with the conditioned media of either human abdominal subcutaneous adipocytes or visceral adipocytes and examined the viability of the cells in the presence of cisplatin, paclitaxel and doxorubicin. We found that the viability of OVCAR-5 cells was significantly increased when treated with conditioned media from subcutaneous adipocytes. Similar results of preliminary studies were obtained with other human ovarian cancer cells (e.g. OVCAR-8 and SKOV-3) and with conditioned media from visceral adipocytes. Increased chemoresistance was also observed in ovarian cancer cells co-cultured with adipocytes in a transwell system. These data suggest that soluble factors secreted from adipocytes, i.e. adipokines, are protective against chemotherapeutic drugs. We then examined the downstream pathways activated in ovarian cancer cells by adipocyte-conditioned media and found that phosphorylated Akt and Stat3 levels were significantly increased in the presence of the adipocyte-conditioned media whereas phosphorylated Erk and p38 levels were not changed. Given that IL-6 is secreted by adipocytes and can activate both Akt and Stat3, we blocked IL-6 in adipocyte-conditioned media with a neutralizing antibody and found that Stat3 activity was inhibited in ovarian cancer cells treated with adipocyte-conditioned media deficient of IL-6 but Akt activity was not affected. However, IL-6 neutralizing antibody did not affect the protective effects of adipocyte-conditioned media on ovarian cancer cells, suggesting that IL-6 and its downstream Stat3 pathway were not involved. Interestingly, the protective effects of adipocytes against cisplatin were abolished when Akt activation was inhibited in ovarian cancer cells by LY294002 treatment, indicating the critical function of Akt pathway in adipocyte-induced chemoresistance. The identity of the adipokine(s) that activates Akt in ovarian cancer cells and confers chemoresistance is currently under investigation. Taken together, these findings demonstrate that abdominal adipocytes enhance the survival of ovarian cancer cells against chemotherapeutic drugs by secreting soluble factor(s) that activates the Akt pathway and identify abdominal adipocytes and associated adipokines as important mediators of ovarian cancer chemoresistance. (This work is supported by the Weitzman Family Fund.)

Citation Format: Jiang Yang, Marsha A. Moses. Adipocytes promote ovarian cancer cell chemoresistance. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr A49.

Abstract 173: Hypercholesterolemia induces angiogenesis and causes accelerated growth of breast tumors in vivo

Background: While many risk factors for breast cancer (BC) such as family history and age have been firmly established, evidence suggests that dietary factors may also play a role in BC. Studies have linked intake of saturated fat as well as metabolic syndrome to an increased prevalence of BC. A common feature shared by metabolic syndrome and a typical American diet is a high level of circulating cholesterol, however a number of epidemiological reports investigating the relationship between high cholesterol levels, cholesterol lowering drugs and BC are conflicting. To determine the relationship between dietary cholesterol and BC in vivo, we modeled this complex condition in a well controlled animal model that utilized an innovative isocaloric diet. We hypothesized that hypercholesterolemia promotes BC progression while hypocholesterolemia has the opposite effect and retards BC progression.

Methods: Female SCID mice were fed a low fat/no cholesterol (LFNC) diet for 2 weeks and then randomized to 4 diet groups with calorie set at 21.2 Kcal/day. These isocaloric diets consisted of a LFNC diet with or without ezetimibe (a drug that specifically blocks cholesterol uptake in the gut, thereby lowering serum cholesterol) and a high fat/high cholesterol (HFHC) diet with and without ezetimibe. Significant differences in serum cholesterol level between groups were achieved and maintained throughout the study. Mice were then implanted orthotopically with MDA-MB-231 BC cells into the 4th mammary fat pad and tumor growth was monitored every 3 days until sacrifice when tumors were harvested.

Results: No differences in tumor take were observed (&gt;95% for all groups). Tumors from animals fed the HFHC diet exhibited the fastest progression. While significant differences in serum cholesterol were observed between the diet groups, no differences were observed in the intratumoral cholesterol levels. To determine the underlying mechanism of cholesterol-induced tumor progression, we assessed tumor proliferation, apoptosis and angiogenesis. Ki67 analyses of tumor proliferation demonstrated a significantly greater percentage of proliferating cells in tumor from mice fed the HFHC diet (48%) compared to animals on the HFHC diet with ezetimibe or the LFNC diet with and without ezetimibe (32%, 33% and 30% respectively). Tumors from hypercholesterolemic animals displayed significantly less apoptosis, as determined by percentage of TUNEL positive cells (39%), compared to the other diet groups (49%, 52% and 58%). Finally, when tumor angiogenesis was evaluated by CD31 staining and microvessel density was quantified, tumors from HFHC mice had vessel areas that were 70% greater, on average, compared to tumors from the other groups.

Conclusion: These results demonstrate that hypercholesterolemia induces angiogenesis and accelerates breast tumor growth in vivo.

Supported by the Breast Cancer Research Foundation and NIH P01 CA045548

Citation Format: Christine M. Coticchia, Kristine Pelton, Adam S. Curatolo, David Zurakowski, Carl P. Schaffner, Keith R. Solomon, Marsha A. Moses. Hypercholesterolemia induces angiogenesis and causes accelerated growth of breast tumors in vivo. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 173. doi:10.1158/1538-7445.AM2013-173

Abstract 361: ZNF24 may modulate microvascular endothelial cell invasion by regulating MMP2 transcription

ZNF24 is a C2H2 zinc finger transcription factor that regulates angiogenesis by repressing the transcription of vascular endothelial growth factor (VEGF). It has also been implicated in the control of cell proliferation and differentiation in the central nervous system and in hepatocellular carcinoma. In the current study, we have focused on the role of ZNF24 in modulating endothelial cell motility. We have found that silencing of ZNF24 in human microvascular endothelial cells (HMVEC) leads to significantly decreased cell migration and invasion. Consistently, the protein level and proteolytic activity of matrix metalloproteinase-2 (MMP2), but not those of matrix metalloproteinase-9 (MMP9), are significantly downregulated when ZNF24 is silenced in these cells. We have also determined the effect of ZNF24 silencing on the mRNA levels of endogenous inhibitors of MMPs, the tissue inhibitors of metalloproteinases (TIMPs). While TIMP1 and TIMP4 levels are moderately upregulated by ZNF24 silencing, the level of TIMP2, a major regulator of MMP2 proteolytic activity, and that of TIMP3, are significantly decreased. However, ZNF24 siRNA induces only a moderate decrease in the protein level of TIMP2, suggesting that TIMP2 does not play an important role in the regulation of MMP9 activity by ZNF24. Another major regulator of MMP2 proteolytic activity, membrane-type-1 matrix metalloproteinase (MT1-MMP), also does not exhibit significant changes when ZNF24 is silenced, suggesting that MMP2 is regulated by ZNF24 at the transcriptional level. Indeed, the mRNA level of MMP2 is significantly downregulated when cells are transfected with ZNF24 siRNA, indicating that ZNF24 positively regulates the transcription of MMP2. When compared to normal endothelial cells, tumor endothelial cells exhibit higher levels of endogenous ZNF24, suggesting that ZNF24 may function to increase cell invasion in these cells via upregulation of MMP2. Our current studies are focused on determining whether MMP2 is a direct downstream target of ZNF24 as well as on its role(s) in modulating endothelial cell motility in vivo. (Supported by NIH P01 CA045548, the Breast Cancer Research Foundation and the Advanced Medical Research Foundation)

Citation Format: Di Jia, Marsha A. Moses. ZNF24 may modulate microvascular endothelial cell invasion by regulating MMP2 transcription. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 361. doi:10.1158/1538-7445.AM2013-361

Large oncosomes in human prostate cancer tissues and in the circulation of mice with metastatic disease

Oncosomes are tumor-derived microvesicles that transmit signaling complexes between cell and tissue compartments. Herein, we show that amoeboid tumor cells export large (1- to 10-μm diameter) vesicles, derived from bulky cellular protrusions, that contain metalloproteinases, RNA, caveolin-1, and the GTPase ADP-ribosylation factor 6, and are biologically active toward tumor cells, endothelial cells, and fibroblasts. We describe methods by which large oncosomes can be selectively sorted by flow cytometry and analyzed independently of vesicles <1 μm. Structures resembling large oncosomes were identified in the circulation of different mouse models of prostate cancer, and their abundance correlated with tumor progression. Similar large vesicles were also identified in human tumor tissues, but they were not detected in the benign compartment. They were more abundant in metastases. Our results suggest that tumor microvesicles substantially larger than exosome-sized particles can be visualized and quantified in tissues and in the circulation, and isolated and characterized using clinically adaptable methods. These findings also suggest a mechanism by which migrating tumor cells condition the tumor microenvironment and distant sites, thereby potentiating advanced disease.

Lipocalin 2 is a novel regulator of angiogenesis in human breast cancer

Lipocalin 2 (Lcn2), a member of the lipocalin family, is up-regulated in a variety of epithelial cancers. We have previously reported that Lcn2 induces the epithelial to mesenchymal transition in breast cancer through the estrogen receptor α/Slug axis and that it is a potential noninvasive biomarker of this disease. Here, we report the novel finding that Lcn2 regulates breast cancer angiogenesis. Vascular endothelial growth factor (VEGF), a key angiogenic activator, was significantly increased with Lcn2 expression in MCF-7 human breast cancer cells as well as in an angiogenic line derived from MDA-MB-436 cells. Treatment with a VEGF-neutralizing antibody demonstrates that VEGF is essential for the angiogenic activity of Lcn2. We further demonstrate that Lcn2-induced VEGF is mediated through hypoxia-inducible factor 1α (HIF-1α) and that Lcn2 regulates HIF-1α through extracellular signal-regulated kinase (Erk). The regulation of HIF-1α and VEGF by Lcn2 was also demonstrated in the aggressive MDA-MB-231 cell line. Using the mouse corneal pocket assay, we found that Lcn2 significantly enhanced the angiogenesis induced by VEGF. Taken together, these results are the first to demonstrate that Lcn2 promotes angiogenesis in vitro and in vivo and suggest a novel mechanism through which Lcn2 may promote tumor progression.

Using breast cancer cell CXCR4 surface expression to predict liposome binding and cytotoxicity

The primary cause of mortality in breast cancer is tumor aggressiveness, characterized by metastases to regional lymph nodes, bone marrow, lung, and liver. C-X-C chemokine receptor type 4 (CXCR4) has been shown to mobilize breast cancer cells along chemokine gradients. Quantification of CXCR4 surface expression may predict the efficacy of anti-CXCR4 labeled liposomal therapeutics to target and kill breast cancer cells. We evaluated gene and surface receptor expression of CXCR4 on breast cancer cell lines distinguished as having low and high invasiveness, MDA-MB-175VII and HCC1500, respectively. CXCR4 surface expression did not correlate with invasiveness. MDA-MB-175VII exhibited more binding to anti-CXCR4 labeled liposomes relative to HCC1500. Increased binding correlated with greater cell death relative to IgG labeled liposomes. Quantitative cell characterization may be used to select targeted therapeutics with enhanced efficacy and minimal side effects.

Endogenous angiogenesis inhibitors prevent adaptive capillary growth in left ventricular pressure overload hypertrophy

BACKGROUND

In left ventricular (LV) pressure-overload hypertrophy, lack of adaptive capillary growth contributes to progression to failure. Remodeling of the hypertrophied myocardium requires proteolysis of the extracellular matrix (ECM) carried out by matrix metalloproteinases (MMPs). MMPs, specifically MMP-9, are known to cleave ECM components to generate angiogenesis inhibitors (angiostatin, endostatin, tumstatin). We hypothesize that MMP-9 releases antiangiogenic factors during compensated and decompensated hypertrophy, which results in lack of adaptive capillary growth.

METHODS

Newborn rabbits underwent aortic banding. Myocardial tissue from age-matched and banded animals at compensated (4 weeks) and decompensated hypertrophy (7 weeks), as identified by serial echocardiography, was analyzed by immunoblotting for angiostatin, endostatin, and tumstatin. MMP-9 activity was determined by zymography. A cell-permeable, potent, selective MMP-9 inhibitor was administered intrapericardially to animals with hypertrophied hearts and tissue was analyzed.

RESULTS

MMP-9 is activated in hypertrophied myocardium versus in control hearts (22 ± 2 versus 16 ± 1; p = 0.04), which results in significantly increased levels of angiostatin (115 ± 10 versus 86 ± 7; p = 0.02), endostatin (33 ± 1 versus 28 ± 1; p = 0.006), and tumstatin (35 ± 6 versus 17 ± 4; p = 0.04). Zymography confirms inhibition of MMP-9 (hypertrophy + MMP-9 inhibitor, 14 ± 0.6 versus hypertrophy + vehicle, 17 ± 1; p = 0.01) and angiostatin, endostatin, and tumstatin are down-regulated, accompanied by up-regulation of capillary density (hypertrophy + MMP-9 inhibitor, 2.99 ± 0.07 versus hypertrophy + vehicle, 2.7 ± 0.05; p = 0.002).

CONCLUSIONS

Up-regulation of angiogenesis inhibitors prevents adaptive capillary growth in pressure-overload hypertrophied myocardium. Therapeutic interventions aimed at inhibition of angiogenesis inhibitors are useful in maintaining capillary density and thereby preventing heart failure.

Cooperative benefit for the combination of rapamycin and imatinib in tuberous sclerosis complex neoplasia

Tuberous sclerosis (TS) is a common autosomal-dominant disorder characterized by tumors of the skin, lung, brain, and kidneys. Monotherapy with rapamycin however resulted in partial regression of tumors, implying the involvement of additional pathways. We have previously implicated platelet-derived growth factor-BB in TS-related tumorigenesis, thus providing a rationale for a combination of mTOR/PDGF blockade using rapamycin and imatinib. Here, we test this combination using a well-established preclinical model of cutaneous tumorigenesis in TS, tsc2ang1 cells derived from a skin tumor from a mouse heterozygous for tsc2. Treatment of tsc2ang1 cells with a combination of rapamycin and imatinib led to an inhibition of proliferation compared with either vehicle treatment or treatment with rapamycin or imatinib monotherapy. Combination therapy also led to a decrease in Akt activation. Potent in vivo activity in animal experiments by combination therapy was noted, without toxicity to the animals. Our findings provide a rationale for the combined use of rapamycin and imatinib, both FDA approved drugs, for the treatment of TS.

Lipocalin 2 expression is associated with aggressive features of endometrial cancer

Background

Increased expression of lipocalin 2 (LCN2) has been observed in several cancers. The aim of the present study was to investigate LCN2 in endometrial cancer in relation to clinico-pathologic phenotype, angiogenesis, markers of epithelial-mesenchymal transition (EMT), and patient survival.

Methods

Immunohistochemical staining was performed using a human LCN2 antibody on a population-based series of endometrial cancer patients collected in Hordaland County (Norway) during 1981-1990 (n = 256). Patients were followed from the time of primary surgery until death or last follow-up in 2007. The median follow-up time for survivors was 17 years. Gene expression data from a prospectively collected endometrial cancer series (n = 76) and a publicly available endometrial cancer series (n = 111) was used for gene correlation studies.

Results

Expression of LCN2 protein, found in 49% of the cases, was associated with non-endometrioid histologic type (p = 0.001), nuclear grade 3 (p = 0.001), >50% solid tumor growth (p = 0.001), ER and PR negativity (p = 0.028 and 0.006), and positive EZH2 expression (p < 0.001). LCN2 expression was significantly associated with expression of VEGF-A (p = 0.021), although not with other angiogenesis markers examined (vascular proliferation index, glomeruloid microvascular proliferation, VEGF-C, VEGF-D or bFGF2 expression). Further, LCN2 was not associated with several EMT-related markers (E-cadherin, N-cadherin, P-cadherin, β-catenin), nor with vascular invasion (tumor cells invading lymphatic or blood vessels). Notably, LCN2 was significantly associated with distant tumor recurrences, as well as with the S100A family of metastasis related genes. Patients with tumors showing no LCN2 expression had the best outcome with 81% 5-year survival, compared to 73% for intermediate and 38% for the small subgroup with strong LCN2 staining (p = 0.007). In multivariate analysis, LCN2 expression was an independent prognostic factor in addition to histologic grade and FIGO stage.

Conclusion

Increased LCN2 expression is associated with aggressive features and poor prognosis in endometrial cancer.

Abstract 5285: ADAM12: A novel mediator of tumor angiogenesis

ADAM12 (a disintegrin and metalloprotease) is a member of a family of integral membrane and secreted Zn-dependent metalloproteases that have diverse roles in normal and pathological states. Human ADAM12 is expressed as two alternatively spliced forms, a membrane-anchored long form (ADAM12-L), and a short secreted form (ADAM12-S). Increased levels of ADAM12 mRNA and protein have been reported in a variety of cancers including colon, hepatocellular, lung, gastric and glioblastoma. We have previously reported that urinary ADAM12 is predictive of disease status and stage in breast cancer. We have also demonstrated that expression of ADAM12 isoforms in breast tumor cells results in a higher rate of tumor take, increased tumor size and endocrine resistance. ADAM12-S expression stimulated migration and invasion of breast tumor cells in vitro and local and distant tumor invasion in vivo. In the course of these studies, we observed that ADAM12 is upregulated in the vessels of aggressive breast tumors as compared to normal adjacent breast tissue. ADAM12-overexpressing breast tumors also displayed a higher microvascular density. Furthermore, we found that angiogenic tumors express higher levels of ADAM12 compared to their preangiogenic counterparts. The goal of the present study was to determine whether ADAM12 regulates tumor angiogenesis. Basal levels of ADAM12-L expression in HUVEC and HMVEC are relatively low, however, both ADAM12 protein and mRNA expression is significantly increased when cells are stimulated with growth factors such as VEGF, bFGF or inflammatory cytokines such as TNFα, TGFβ or IL1α. Interestingly, VEGF stimulation of endothelial cells (EC) resulted in ADAM12 protein expression and/or localization specifically along the invadopodia of these cells. Consistent with these results, we found that ADAM12 overexpression in EC resulted in significantly increased rates of migration, capillary tube formation and increased adhesion to fibronectin and type IV collagen but not laminin. In vivo studies demonstrate that ADAM12 significantly increases bFGF-mediated angiogenesis in the mouse corneal pocket assay. Taken together, our data provide evidence supporting a novel role for ADAM12 in the regulation of endothelial cell function and tumor angiogenesis. Studies to investigate the mechanism/s by which ADAM12 may regulate angiogenesis are ongoing. [The authors acknowledge the support of NIH PO1 CA045548, The Breast Cancer Research Foundation and The Simeon J. Fortin Foundation]

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5285. doi:1538-7445.AM2012-5285

Forty-year journey of angiogenesis translational research

Forty years ago, Judah Folkman predicted that tumor growth is dependent on angiogenesis and that inhibiting this process might be a new strategy for cancer therapy. This hypothesis formed the foundation of a new field of research that represents an excellent example of how a groundbreaking scientific discovery can be translated to yield benefits for patients. Today, antiangiogenic drugs are used to treat human cancers and retinal vascular diseases. Here, we guide readers through 40 years of angiogenesis research and discuss challenges of antiangiogenic therapy.

Potential of fluorescent metalloproteinase substrates for cancer detection

OBJECTIVES

MMP-2, MMP-9, their complexes and ADAM12 are detected in the urine of breast cancer patients and predict disease status. We assessed the use of FRET-based substrates in an assay to distinguish breast cancer patients from controls.

DESIGN AND METHODS

Substrates with varying specificities for MMP-9 and MMP-2 and several ADAMs were screened. Flsub21 and Flsub13, substrates for ADAM12 and ADAM8 respectively, were studied.

RESULTS

Flsub21 and Flsub13 cleavage activities were detected in the urine of patients with invasive and metastatic breast cancers at significantly higher frequencies compared to controls. Our model predicted probabilities of 90% when both Flsub21 and Flsub13 were positive, 65% when Flsub21 alone was positive, 55% when Flsub13 alone was positive and 20% when both substrates were negative.

CONCLUSIONS

These data suggest the potential utility of FRET substrates to non-invasively identify invasive and/or metastatic breast cancer.

Age-dependent loss of MMP-3 in Hutchinson-Gilford progeria syndrome

Hutchinson-Gilford progeria syndrome (HGPS) is a rare, progressive segmental premature aging disease that includes scleroderma-like skin, progressive joint contracture, and atherosclerosis. Affected individuals die prematurely of heart attacks or strokes. Extracellular matrix dysregulation is implicated as a factor in disease progression. We analyzed messenger RNA and protein levels for matrix metalloproteinases (MMPs)-2,-3, and -9 in HGPS primary human dermal fibroblasts using real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and gelatin zymography. MMP-3 messenger RNA and protein levels decreased significantly with increasing donor age in HGPS fibroblasts but not in controls. MMP-2 messenger RNA also showed a donor age-dependent decrease in HGPS fibroblasts, but levels of secreted protein were unchanged. MMP-9 was similar in HGPS and control cultures. The decreased MMP-3 may represent a shift in the inherent extracellular matrix-degrading proteolytic balance in favor of matrix deposition in HGPS. This metalloproteinase has the potential to serve as a biomarker of therapeutic efficacy when assessing treatments for HGPS.

ADAM12 transmembrane and secreted isoforms promote breast tumor growth: a distinct role for ADAM12-S protein in tumor metastasis

Increased levels of ADAM12 have been reported in a variety of human cancers. We have previously reported that urinary ADAM12 is predictive of disease status in breast cancer patients and that ADAM12 protein levels in urine increase with progression of disease. On the basis of these findings, the goal of this study was to elucidate the contribution of ADAM12 in breast tumor growth and progression. Overexpression of both the ADAM12-L (transmembrane) and ADAM12-S (secreted) isoforms in human breast tumor cells resulted in a significantly higher rate of tumor take and increased tumor size. Cells expressing the enzymatically inactive form of the secreted isoform, ADAM12-S, had tumor take rates and tumor volumes similar to those of wild-type cells, suggesting that the tumor-promoting activity of ADAM12-S was a function of its proteolytic activity. Of the two isoforms, only the secreted isoform, ADAM12-S, enhanced the ability of tumor cells to migrate and invade in vitro and resulted in a higher incidence of local and distant metastasis in vivo. This stimulatory effect of ADAM12-S on migration and invasion was dependent on its catalytic activity. Expression of both ADAM12 isoforms was found to be significantly elevated in human malignant breast tissue. Taken together, our results suggest that ADAM12 overexpression results in increased tumor take, tumor size, and metastasis in vivo. These findings suggest that ADAM12 may represent a potential therapeutic target in breast cancer.

Safety, Efficacy, and Biomarker Exploration in a Phase II Study of Bevacizumab, Oxaliplatin, and Gemcitabine in Recurrent Müllerian Carcinoma

OBJECTIVE: To explore the safety, efficacy, and biomarkers of bevacizumab with gemcitabine and oxaliplatin in women with recurrent platinum-sensitive ovarian carcinoma. METHODS: The patients received bevacizumab (10 mg/kg), gemcitabine (1000 mg/m(2)), and oxaliplatin (65 mg/m(2)) on days 1 and 15 in 28-day cycles. The patients with safely accessible tumor underwent intratumoral fluid pressure (IFP) measurements and positron-emission tomographies immediately and 2 weeks after treatment. Blood biomarkers were evaluated at 5 time points. RESULTS: The trial was closed after enrolling 19 of the 53 projected patient accrual. Thirteen (68.5%) of 19 patients showed a response (1 complete response, 12 partial responses), and 6 patients showed stable disease (31.6%). Median progressive-free survival was 36.9 weeks (258.3 days), and the median overall survival was 112.3 weeks (633 days, not reached). Toxicity was acceptable, and there were no arterial thromboses, serious bleeding, gastrointestinal perforations, or complications from the invasive procedures. Bevacizumab with chemotherapy induced a substantial drop in tumor IFP after treatment. The regimen induced sustained elevation in circulating plasma vascular endothelial growth factor (VEGF), placental growth factor (PlGF), basic fibroblast growth factor (bFGF), soluable vascular endothelial growth factor receptor 2 (sVEGFR2), and circulating progenitor cells. Plasma PlGF, VEGFR2(+) monocytes, and urinary matrix metalloproteinase 2 activity showed differential associations with treatment outcome when evaluated at baseline and after 14 days of treatment. CONCLUSIONS: Despite early termination of the study, the results indicate that the regimen was well tolerated and demonstrated activity in platinum-sensitive ovarian cancer. Biomarker evaluations showed that bevacizumab with chemotherapy significantly changed the levels of several circulating cellular and molecular biomarkers. The increases in plasma PlGF and VEGFR2(+) monocytes showed correlations with outcome. These exploratory data should be further evaluated in future studies of bevacizumab in ovarian cancer.

Adult mouse epicardium modulates myocardial injury by secreting paracrine factors

The epicardium makes essential cellular and paracrine contributions to the growth of the fetal myocardium and the formation of the coronary vasculature. However, whether the epicardium has similar roles postnatally in the normal and injured heart remains enigmatic. Here, we have investigated this question using genetic fate-mapping approaches in mice. In uninjured postnatal heart, epicardial cells were quiescent. Myocardial infarction increased epicardial cell proliferation and stimulated formation of epicardium-derived cells (EPDCs), which remained in a thickened layer on the surface of the heart. EPDCs did not adopt cardiomyocyte or coronary EC fates, but rather differentiated into mesenchymal cells expressing fibroblast and smooth muscle cell markers. In vitro and in vivo assays demonstrated that EPDCs secreted paracrine factors that strongly promoted angiogenesis. In a myocardial infarction model, EPDC-conditioned medium reduced infarct size and improved heart function. Our findings indicate that epicardium modulates the cardiac injury response by conditioning the subepicardial environment, potentially offering a new therapeutic strategy for cardiac protection.

Abstract 3188: Discovery and validation of non-invasive biomarkers for benign prostate hyperplasia and prostate cancer

Although the PSA test is successfully used to determine how well a prostate cancer patient is responding to therapy, it cannot reliably distinguish between the presence of prostate cancer and benign prostate diseases such as benign prostatic hyperplasia (BPH) or prostatitis. These conditions and early prostate cancer can all result in low to moderate levels of PSA in the blood. The absence of sensitive and specific biomarkers that can distinguish between benign conditions and prostate cancer often leaves patients and their doctors with little recourse than to utilize invasive approaches to diagnose prostate cancer that can result in harmful and undesirable side effects. With the goal of identifying and validating non-invasive biomarkers that can distinguish between neoplastic and non-neoplastic disease of the prostate, we have utilized iTRAQ (isobaric tag for relative and absolute quantitation) as our technique of choice to sensitively and accurately identify and quantify proteins that are differentially present in the urine of men with BPH and prostate cancer. This approach resulted in the identification of 26 proteins that were differentially expressed at a significant level, with high confidence, in urines obtained from men from each of the two groups of interest. These proteins represent a number of functional categories including cell assembly and organization, cell signaling, cell morphology, carbohydrate metabolism, cellular growth and proliferation, lipid metabolism, androgen and estrogen metabolism and DNA replication, recombination and repair, among others. Validation of ten proteins with the greatest differential expression between the two groups has been completed. Immunoblot analyses have confirmed the significant differential presence of these proteins in a larger number of patient samples analyzed thus far. Large scale validation studies are ongoing. These data suggest that the ability to non-invasively monitor the levels of these proteins in the urine of patients with uninformative PSA levels has the potential to provide clinically relevant information for reliable diagnosis of BPH and prostate cancer. These proteins may also serve as potential therapeutic targets for the treatment of men with BPH and prostate cancer. (Supported by The Ellison Foundation)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3188. doi:10.1158/1538-7445.AM2011-3188

Abstract 2818: Urinary MMP-2 and MMP-9 predict the presence of ovarian cancer in women with normal CA125 levels

Currently, the only widely used biomarker for monitoring ovarian cancer status and response to therapy is the cancer antigen 125 (CA125). Interestingly, the majority of newly developed ovarian cancer multi-marker assays also rely heavily on serum CA125 levels as one of the biomarkers in their panels. However, 20% of women with advanced ovarian cancer have blood CA125 levels within the normal range of 35 U/mL and below. These women represent a cohort of patients for whom no clinically useful biomarkers are available for monitoring disease status, stage or response to therapy. To address this need, we asked whether a panel of urinary biomarkers that we have previously validated for use in other cancers, could predict the presence of disease in women with ovarian cancer possessing normal CA125 levels. Urine samples were collected from 81 healthy controls and 26 ovarian cancer patients with blood CA125 levels below 35 U/mL. Using monospecific ELISAs, we determined that urinary levels of matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) and the neutrophil gelatinase lipocalin 2 (NGAL) are detected at significantly higher levels in the urine of ovarian cancer patients than in the urine of healthy controls. Additionally, receiver-operating characteristic (ROC) area under the curve (AUC) analysis of these groups revealed that, individually, MMP-2, MMP-9 and NGAL each could significantly distinguish ovarian cancer patients with CA125 &lt; 35 U/mL from controls. The best combination of biomarkers for predicting the presence of disease was MMP-2 plus MMP-9 with an ROC AUC of 0.7332 (P&lt;0.01). When these biomarkers were multiplexed with age, a know risk factor of ovarian cancer, the diagnostic accuracy of these biomarkers increased to an AUC of 0.820 (P&lt;0.001). This combination of urinary MMP-2, MMP-9 and age demonstrated excellent diagnostic capability in differentiating ovarian cancer patients from healthy controls among the cohort of patients for whom CA125 values were uninformative.

Acknowledgments: The authors gratefully acknowledge the support of Ovations for the Cure of Ovarian Cancer (MAM and UAM) and the Stuart Weitzman Foundation (MAM).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2818. doi:10.1158/1538-7445.AM2011-2818

A role for cysteine-rich 61 in the angiogenic switch during the estrous cycle in cows: regulation by prostaglandin F2alpha

The development and demise of the corpus luteum (CL) are accompanied by angiogenic and angioregressive processes; however, the mediators of these processes have not been fully identified and characterized. Transcriptional profiling studies revealed the upregulation of cysteine-rich 61 (CYR61) in the CL, about which nothing was previously known. In the present study, we found that over a 12-h period following a single injection of prostaglandin F(2alpha) (PGF(2alpha)), RT-PCR revealed the upregulation of CYR61 at 0.5 and 1 h, after which it declined. We also determined that luteal-derived endothelial cells as well as luteal steroidogenic cells are sources of CYR61. Treatment with PGF(2alpha) in vitro had no effect on CYR61 expression in luteal-derived endothelial cells, but it increased CYR61 expression in luteal steroidogenic cells. During the estrous cycle, CYR61/CYR61 (transcript/protein) was increased in the Day 4 but not in the Day 10 and Day 16 CL, suggesting that it may be associated with the switch to the angiogenic phenotype. In addition, the specific but transient upregulation of CYR61 by PGF(2alpha) in vivo, and in luteal steroidogenic cells but not endothelial cells in vitro, may be part of the mechanism underlying the previously reported transient increase in blood flow during the early onset of luteolysis. This is supported by our preliminary finding that CYR61 transiently inhibited endothelial cell expression of endothelin-converting enzyme 1 mRNA but not endothelin 1. Collectively, the increased expression of CYR61 in the Day 4 CL and its transient increase by PGF(2alpha) in Day 6, Day 10, and Day 16 CL indicate that CYR61 may play a role in regulating angiogenesis over the life span of the CL.

ADAM12 induces estrogen-independence in breast cancer cells

Antiestrogen therapy has been used successfully to prolong disease-free and overall survival of ER positive breast cancer patients. However, 50% of patients with ER+ tumors fail to respond to such therapy or eventually acquire resistance to endocrine therapy, resulting in tumor progression and mortality. It is imperative, therefore, to understand the mechanisms that lead to hormone refractory breast cancer in order to develop therapeutics that can modulate the resistance to antiestrogen therapy. The protease, ADAM12, can be detected in the urine of breast cancer patients and its levels correlate with disease status, stage, and cancer risk. Within the context of this study, the authors have investigated the role of the two distinct isoforms of ADAM12 in breast tumor cell proliferation and as potential mediators of endocrine resistance. Using stable clones of ADAM12-overexpressing MCF-7 cells, the authors analyzed proliferation rates of these ER+ breast tumor cells both in estrogen-depleted medium and in the presence of the antiestrogens, tamoxifen, and ICI 182,780. Acquired estrogen resistance in these cells was analyzed using phospho-RTK analysis. Upregulation and phosphorylation of proteins were detected via immunoprecipitation and immunoblotting. EGFR and MAPK inhibitors were used to explore the mechanism of acquired estrogen resistance in breast tumor cells. It was observed that overexpression of the two isoforms, transmembrane ADAM12-L, and secreted ADAM12-S, in breast tumor cells promoted estrogen-independent proliferation. In ADAM12-L-expressing cells, estrogen-independence was a direct result of increased EGFR expression and MAPK activation, whereas, the mechanism in ADAM12-S-expressing cells may be enhanced IGF-1R signaling. The importance of the EGFR signaling pathway in the estrogen-independent growth of ADAM12-L expressing cells was highlighted by the effect of EGFR inhibitors AG1478 and PD15035 or MAPK inhibitor U0126, each of which abolished the antiestrogen resistance in these cells. Taken together, these results demonstrate that ADAM12 isoforms confer a proliferative advantage to MCF-7 cells in the absence of estrogen stimulation, and suggest that downregulation of ADAM12 in combination with endocrine therapy may represent a useful pharmacological approach to breast cancer therapy.

The anti-angiogenic peptide, loop 6, binds insulin-like growth factor-1 receptor

Tissue inhibitors of metalloproteinases (TIMPs), the endogenous inhibitors of matrix metalloproteinases, have been shown to possess biological functions that are independent of their ability to inhibit matrix metalloproteinases. We have previously shown that the C-terminal domain of TIMP-2 and, in particular, Loop 6 inhibit capillary endothelial cell proliferation and angiogenesis both in vitro and in vivo. To elucidate the mechanism by which Loop 6 inhibits angiogenesis, we sought to determine whether its biological effects were the result of a known TIMP-2 protein-protein interaction or of a receptor-mediated event. In this study, we identify insulin-like growth factor-1 receptor as a binding partner of Loop 6/TIMP-2 and characterize this interaction on the endothelial cell surface and the consequences of this interaction on downstream receptor signaling.

Phase II study of cediranib, an oral pan-vascular endothelial growth factor receptor tyrosine kinase inhibitor, in patients with recurrent glioblastoma

PURPOSE

Glioblastoma is an incurable solid tumor characterized by increased expression of vascular endothelial growth factor (VEGF). We performed a phase II study of cediranib in patients with recurrent glioblastoma.

METHODS

Cediranib, an oral pan-VEGF receptor tyrosine kinase inhibitor, was administered (45 mg/d) until progression or unacceptable toxicity to patients with recurrent glioblastoma. The primary end point was the proportion of patients alive and progression free at 6 months (APF6). We performed magnetic resonance imaging (MRI) and plasma and urinary biomarker evaluations at multiple time points.

RESULTS

Thirty-one patients with recurrent glioblastoma were accrued. APF6 after cediranib was 25.8%. Radiographic partial responses were observed by MRI in 17 (56.7%) of 30 evaluable patients using three-dimensional measurements and in eight (27%) of 30 evaluable patients using two-dimensional measurements. For the 15 patients who entered the study taking corticosteroids, the dose was reduced (n = 10) or discontinued (n = 5). Toxicities were manageable. Grade 3/4 toxicities included hypertension (four of 31; 12.9%); diarrhea (two of 31; 6.4%); and fatigue (six of 31; 19.4%). Fifteen (48.4%) of 31 patients required at least one dose reduction and 15 patients required temporary drug interruptions due to toxicity. Drug interruptions were not associated with outcome. Changes in plasma placental growth factor, basic fibroblast growth factor, matrix metalloproteinase (MMP) -2, soluble VEGF receptor 1, stromal cell-derived factor-1alpha, and soluble Tek/Tie2 receptor and in urinary MMP-9/neutrophil gelatinase-associated lipocalin activity after cediranib were associated with radiographic response or survival.

CONCLUSION

Cediranib monotherapy for recurrent glioblastoma is associated with encouraging proportions of radiographic response, 6-month progression-free survival, and a steroid-sparing effect with manageable toxicity. We identified early changes in circulating molecules as potential biomarkers of response to cediranib. The efficacy of cediranib and the predictive value of these candidate biomarkers will be explored in prospective trials.

Abstract 416: ADAM12 long and short isoforms promote breast tumor growth and metastasis via distinct mechanisms

Human ADAM12 is expressed as two alternatively spliced forms, a transmembrane form (ADAM12-L), and a secreted form (ADAM12-S). ADAM12 transcript and protein levels are elevated in several types of cancers. We have previously reported that urinary ADAM12 is predictive of disease status in breast cancer patients and that ADAM12 protein levels in urine increase with progression of disease. In this study, our goal was to elucidate the contribution of the isoforms of ADAM12 in breast tumor growth and progression. We engineered stable MCF-7 clones that overexpress ADAM12-L or ADAM12-S and characterized their properties in vitro as well as in an orthotopic breast tumor model. Overexpression of both the transmembrane ADAM12-L and the secreted ADAM12-S isoforms in breast tumor cells resulted in a significantly higher rate of tumor take and increased tumor size. ADAM12-S-expressing tumors also displayed a significantly higher incidence of lymph node and lung metastasis as compared to ADAM12-L and WT MCF-7 tumors respectively. ADAM12-S expression enhanced the ability of tumor cells to migrate and invade in vitro based on its catalytic function, whereas both isoforms conferred estrogen-independent growth capabilities to hormone responsive MCF-7 cells. In ADAM12-L-expressing breast tumor cells, this enhanced proliferation was a direct result of increased EGFR expression and activation and downstream MAPK signaling. This was confirmed when treatment with EGFR inhibitors AG1478 or PD15035 or the MAPK inhibitor U0126 resulted in complete abrogation of estrogen-independent growth in these cells. However, for ADAM12-S-expressing cells, the increased activation of MAPK and proliferation may be due to an alternate mechanism. We have also determined that ADAM12 protein and mRNA expression is elevated in malignant tissue as compared to normal breast tissue via analysis of human breast tissue arrays. Interestingly, there appears to be a differential expression pattern of the transmembrane and secreted isoforms during breast tumor progression. Taken together, our results suggest that ADAM12-S, via its catalytic function enhances the ability of malignant cells to locally invade and form distant metastasis. Expression of both ADAM12 isoforms may confer a proliferative advantage to breast tumor cells in the absence of estrogen stimulation, although via distinct mechanisms, resulting in increased tumor take, tumor size and metastasis in vivo. These findings highlight the therapeutic potential of targeting ADAM12, given that hormone independence is a hallmark of aggressive breast cancer. [The authors acknowledge the support of NIH PO1 CA45548, The JoAnn Webb Fund for Angiogenesis Research and The Fortin Foundation]

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 416.

Abstract 1293: Neutrophil gelatinase-associated lipocalin regulates the expression of angiogenic cytokines and VEGF in human breast and ovarian cancer cells

Neutrophil gelatinase-associated lipocalin (NGAL; lipocalin 2) is a small extracellular protein (25 kDa) that is a member of the lipocalin protein family. It has been shown to bind ferric siderophores and to play an important role in iron metabolism. Increased NGAL levels have been reported in a variety of epithelial cancers, including breast, ovary, pancreas, colon, esophagus and thyroid cancer. We have recently reported that NGAL promotes breast cancer progression by inducing the epithelial to mesenchymal transition. In the course of these studies, we observed an increase in microvessel density in NGAL-expressing tumors. In the current study, we explored the potential role of NGAL in tumor angiogenesis by studying its effects on the expression of angiogenic factors. We first determined the levels of vascular endothelial growth factor (VEGF) in NGAL-expressing cells derived from the MCF-7 human breast cancer cell line. Using reverse-transcriptase PCR and ELISA, VEGF was found to be induced by NGAL at both the transcript and protein levels. Consistently, HIF-1α, one of the most important transcriptional regulators of VEGF, was observed to be accumulated in the nuclei of NGAL-expressing cells. Silencing of HIF-1α in NGAL-expressing cells significantly reduced VEGF expression. Consistent with this NGAL-induced VEGF production, there was a significant increase in endothelial cell migration towards the conditioned media collected from NGAL-expressing cells. Interestingly, treatment with a VEGF-neutralizing antibody only partially inhibited the migration-inducing activity of the conditioned media, suggesting that NGAL might induce the secretion of other angiogenic factors. To investigate this possibility, a panel of angiogenic factors was compared between the conditioned media collected from NGAL-expressing cells and control MCF-7 cells using antibody arrays. Several angiogenic cytokines, including IL-6, MCP-1 and GM-CSF, were found to be upregulated with NGAL expression. The effects of NGAL on VEGF and angiogenic cytokine production were also studied in SKOV-3 ovarian cancer cells. In this study, NGAL was silenced in SKOV-3 cells using specific siRNAs. The levels of both VEGF and IL-6 were found to be reduced after NGAL silencing, suggesting that NGAL's control of VEGF and cytokine production may be common among cancer cell types. These results suggest a novel mechanism through which NGAL may promote tumor angiogenesis and progression. (This work is supported by NIH R01 CA118764, P01 CA045548 and The Advanced Medical Foundation.)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1293.

Abstract 2719: Non-invasive biomarker discovery for ovarian cancer

The majority of women with ovarian cancer are diagnosed with advanced disease (FIGO stage III and IV) and have a five year survival rate of approximately 20%. In contrast, the survival rate of women diagnosed with stage I ovarian cancer is greater than 90%, highlighting an unmet and dire need for accurate and reliable diagnostic tests for the early detection of ovarian cancer. We have previously demonstrated that urinary matrix metalloproteinases (MMPs) are independent predictors of disease status and stage in a variety of human cancers as well as predictors of breast cancer risk. We have also reported that neutrophil gelatinase-associated lipocalin (NGAL) is present in the urine of women with metastatic breast cancer and that the levels of urinary NGAL are significantly higher in these patients compared to normal controls. In the current study, we asked whether urinary MMPs and NGAL, alone or in combination, could provide useful clinical information with respect to the presence of ovarian cancer. Urine samples were obtained from a total of 166 women: 96 women with known FIGO stage III and IV ovarian cancer (newly diagnosed and recurrent) and 70 normal controls. All urine samples were analyzed for NGAL levels by ELISA and for urinary MMP levels by quantitative gelatin zymography. We found that urinary NGAL, MMP9-dimer, MMP9/NGAL complex, MMP9, and MMP2 were each significantly elevated in the urine of women with ovarian cancer compared to normal controls (p&lt;0.001). Receiver operating characteristic (ROC) curve analysis indicated that the area under the curve (AUC) for each individual urinary matrix metalloproteinase biomarker and NGAL was statically significant: AUC= 0.706 for MMP9-dimer (p&lt;0.001), AUC=0.645 for MMP9/NGAL complex (p&lt;0.001), AUC= 0.712 for MMP9 (p&lt;0.001), AUC=0.681 for MMP2 (p&lt;0.001), and AUC=0.668 for NGAL (p&lt;0.001). Among these biomarkers, multivariable logistic regression confirmed that MMP9-dimer multiplexed with MMP2 (MMP9-dimer/MMP2) provided optimal diagnostic information for differentiating between the ovarian cancer and control groups AUC = 0.753, (95% confidence interval (CI) = 0.680 – 0.827, (p&lt;0.001)). Interestingly, when these multivariate predictors were combined with another known risk factor for ovarian cancer, that being age, we found that women &gt;55 years of age with significant measurable levels of urinary MMP9-dimer and MMP2 had a 95% probability of ovarian cancer (95% CI= 85-98% probability), AUC = 0.860 (95% CI = 0.802 – 0.915 (p&lt;0.001)). Taken together, these data suggest that the panel of urinary biomarkers composed of gelatinases, their complexes and NGAL, along with patient age, may provide clinically useful information with respect to distinguishing between women who have ovarian cancer and those who do not.

(Supported by NIH P01 CA045548, the Weitzman Family Foundation and Ovations for the Cure)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2719.

Abstract LB-242: Oncosomes: Large bioactive particles secreted by prostate cancer cells

Purpose of the study: Human prostate tumor cells were recently shown by our group to secrete large (0.5-10 m diameter) bioactive microvesicles capable of activating signal transduction and inducing proliferation and migration in cells in the tumor microenvironment (Di Vizio, et al. Cancer Res. 2009 69: 5601-9). These secreted particles, termed oncosomes, were shown to be vehicles for numerous signaling proteins involved in cell growth and motility. They also contain the membrane protein caveolin-1 (Cav-1), a mediator of prostate cancer (PCa) metastasis and a circulating PCa biomarker. The purpose of this study was to develop the tools to identify, isolate, sort and characterize PCa-derived oncosomes.

Experimental procedures: Secreted particles from PCa cells were ultracentrifuged at 100,000xg and the pelleted material processed on a Moflo High-Speed Cell Sorter (Beckman-Coulter) and analyzed using Summit V4.3 software (Dako Colorado, Inc.). 1, 3 and 10 m bead standards (Spherotech Inc.) were used to set size gates. To avoid capturing aggregated material, forward scatter and pulse width were set at a linear scale and only single events were gated and analyzed. Sorted particles were visualized by confocal and electron microscopy.

Results: Using the above procedure, we were able to retrieve intact particles of 1-10 m in diameter secreted by LNCaP cells overexpressing the oncoprotein MyrAkt1. The nontumorigenic prostate stromal cell line WPMY-1 secreted &gt; 10-fold fewer particles in this size range. We confirmed that these were membrane-derived particles by showing that they contained MyrAkt1, which localizes to the plasma membrane. Particles in a similar size range were also sorted after purification from LNCaP cells stably expressing a Cav-1/GFP fusion protein. Sorted particles visualized microscopically appeared to be surrounded by a lipid bilayer and to have intrinsic structure that made them resistant to collapse. Particles isolated by these methods evoked degradation of FITC-labeled collagen and contained active MMP9 and MMP2, two key proteases involved in tumor cell invasion.

Conclusions: The specific type of large bioactive particle we have isolated has not been previously described in any tumor system. Studies are ongoing to detect these particles in animal models of cancer and in human patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-242.

Effects of metalloproteinase inhibition in a murine model of renal ischemia-reperfusion injury

Ischemia-reperfusion injury (IRI) is a leading cause of acute tubular necrosis (ATN) and delayed graft function in transplanted organs. Up-regulation of matrix metalloproteinases (MMPs) propagates the microinflammatory response that drives IRI. This study sought to determine the specific effects of Marimastat (Vernalis, BB-2516), a broad spectrum MMP and TNF-alpha-converting enzyme inhibitor, on IRI-induced ATN. Mice were pretreated with Marimastat or methylcellulose vehicle for 4 d before surgery. Renal pedicles were bilaterally occluded for 30 min and allowed to reperfuse for 24 h. Baseline creatinine levels were consistent between experimental groups; however, post-IRI creatinine levels were 4-fold higher in control mice (p < 0.0001). The mean difference between the post-IRI histology grades of Marimastat-treated and control kidneys was 1.57 (p = 0.003), demonstrating more severe damage to control kidneys. Post-IRI mean (+/-SEM) MMP-2 activity rose from baseline levels in control mice (3.62 +/- 0.99); however, pretreated mice presented only a slight increase in mean MMP-2 activity (1.57 +/- 0.72) (p < 0.001). In conclusion, these data demonstrate that MMP inhibition is associated with a reduction of IRI in a murine model.

Endothelial progenitor cells as a sole source for ex vivo seeding of tissue-engineered heart valves

PURPOSES

We investigated whether circulating endothelial progenitor cells (EPCs) can be used as a cell source for the creation of a tissue-engineered heart valve (TEHV).

METHODS

Trileaflet valved conduits were fabricated using nonwoven polyglycolic acid/poly-4-hydroxybutyrate polymer. Ovine peripheral blood EPCs were dynamically seeded onto a valved conduit and incubated for 7, 14, and 21 days.

RESULTS

Before seeding, EPCs were shown to express CD31(+), eNOS(+), and VE-Cadherin(+) but not alpha-smooth muscle actin. Histological analysis demonstrated relatively homogenous cellular ingrowth throughout the valved conduit. TEHV constructs revealed the presence of endothelial cell (EC) markers and alpha-smooth muscle actin(+) cells comparable with native valves. Protein levels were comparable with native valves and exceeded those in unseeded controls. EPC-TEHV demonstrated a temporal pattern of matrix metalloproteinases-2/9 expression and tissue inhibitors of metalloproteinase activities comparable to that of native valves. Mechanical properties of EPC-TEHV demonstrated significantly greater stiffness than that of the unseeded scaffolds and native valves.

CONCLUSIONS

Circulating EPC appears to have the potential to provide both interstitial and endothelial functions and could potentially serve as a single-cell source for construction of autologous heart valves.

Prenatal urinary matrix metalloproteinase profiling as a potential diagnostic tool in fetal obstructive uropathy

BACKGROUND/PURPOSE

The diagnostic evaluation, patient stratification, and prenatal counseling for congenital obstructive uropathy remain sub-optimal. Matrix metalloproteinase (MMP) expression profiles are emerging as a valuable diagnostic tool in assorted disease processes. We sought to determine whether congenital obstructive uropathy impacts MMP expression in fetal urine.

METHODS

Fetal lambs (n = 25) were divided in two groups: group I (n = 12) underwent a sham operation and group II (n = 13) underwent creation of a complete urinary tract obstruction. Gelatin zymography panels for 4 MMP species were performed on fetal urine in both groups at comparable times post-operatively. Statistical analysis was by the Fisher's exact test (P < .05).

RESULTS

Overall fetal survival was 80% (20/25). A variety of significant differences in MMP expression between the two groups were identified. The following profiles were present only in obstructed animals: any MMP other than MMP-2 (P = .029), including any MMP other than 63 kDa and 65 kDa (P = .009); 2 or more MMPs excluding MMP-2s (0.029); and 3 or more MMPs (P = .029).

CONCLUSIONS

Limited matrix metalloproteinase expression is present in the urine of normal ovine fetuses. Fetal obstructive uropathy impacts urinary MMP expression in various distinguishable patterns. Prenatal urinary MMP profiling may become a practical and valuable diagnostic tool in the evaluation of congenital obstructive uropathy.

Matrix metalloproteinases as novel biomarkers and potential therapeutic targets in human cancer

The matrix metalloproteinase (MMP) family of enzymes is comprised of critically important extracellular matrix remodeling proteases whose activity has been implicated in a number of key normal and pathologic processes. The latter include tumor growth, progression, and metastasis as well as the dysregulated angiogenesis that is associated with these events. As a result, these proteases have come to represent important therapeutic and diagnostic targets for the treatment and detection of human cancers. In this review, we summarize the literature that establishes these enzymes as important clinical targets, discuss the complexity surrounding their choice as such, and chronicle the development strategies and outcomes of their clinical testing to date. The status of the MMP inhibitors currently in US Food and Drug Administration approved clinical trials is presented and reviewed. We also discuss the more recent and successful targeting of this enzyme family as diagnostic and prognostic predictors of human cancer, its status, and its stage. This analysis includes a wide variety of human cancers and a number of human sample types including tissue, plasma, serum, and urine.

Matrix metalloproteinases as novel biomarkers and potential therapeutic targets in human cancer

The matrix metalloproteinase (MMP) family of enzymes is comprised of critically important extracellular matrix remodeling proteases whose activity has been implicated in a number of key normal and pathologic processes. The latter include tumor growth, progression, and metastasis as well as the dysregulated angiogenesis that is associated with these events. As a result, these proteases have come to represent important therapeutic and diagnostic targets for the treatment and detection of human cancers. In this review, we summarize the literature that establishes these enzymes as important clinical targets, discuss the complexity surrounding their choice as such, and chronicle the development strategies and outcomes of their clinical testing to date. The status of the MMP inhibitors currently in US Food and Drug Administration approved clinical trials is presented and reviewed. We also discuss the more recent and successful targeting of this enzyme family as diagnostic and prognostic predictors of human cancer, its status, and its stage. This analysis includes a wide variety of human cancers and a number of human sample types including tissue, plasma, serum, and urine.

Matrix metalloproteinases as novel biomarkers and potential therapeutic targets in human cancer

The matrix metalloproteinase (MMP) family of enzymes is comprised of critically important extracellular matrix remodeling proteases whose activity has been implicated in a number of key normal and pathologic processes. The latter include tumor growth, progression, and metastasis as well as the dysregulated angiogenesis that is associated with these events. As a result, these proteases have come to represent important therapeutic and diagnostic targets for the treatment and detection of human cancers. In this review, we summarize the literature that establishes these enzymes as important clinical targets, discuss the complexity surrounding their choice as such, and chronicle the development strategies and outcomes of their clinical testing to date. The status of the MMP inhibitors currently in US Food and Drug Administration approved clinical trials is presented and reviewed. We also discuss the more recent and successful targeting of this enzyme family as diagnostic and prognostic predictors of human cancer, its status, and its stage. This analysis includes a wide variety of human cancers and a number of human sample types including tissue, plasma, serum, and urine.

Lipocalin 2: a multifaceted modulator of human cancer

Lipocalin 2 (Lcn2), a member of the lipocalin family that transports small lipophilic ligands, has gained recent attention as both a potential biomarker and a modulator of human cancers. Here we describe recent findings of the functions of Lcn2 in breast cancer and the potential mechanisms that underlie its actions. Lcn2 has been shown to induce the epithelial to mesenchymal transition (EMT) in breast cancer cells and to promote breast tumor invasion. Estrogen receptor alpha may participate in the pathway that leads to Lcn2-induced EMT. Preliminary evidence also suggests that Lcn2 may be useful as a potential non-invasive urinary biomarker of breast cancer. Elevated levels of Lcn2 have also been reported in other human cancers. The potential roles of Lcn2 in epithelial tumors as well as leukemia are also reviewed and discussed here.

VEGF-A induces angiogenesis by perturbing the cathepsin-cysteine protease inhibitor balance in venules, causing basement membrane degradation and mother vessel formation

Tumors initiate angiogenesis primarily by secreting vascular endothelial growth factor (VEGF-A(164)). The first new vessels to form are greatly enlarged, pericyte-poor sinusoids, called mother vessels (MV), that originate from preexisting venules. We postulated that the venular enlargement necessary to form MV would require a selective degradation of their basement membranes, rigid structures that resist vascular expansion. To identify the specific proteases responsible for MV formation, we induced angiogenesis in mouse tissues with an adenoviral vector expressing VEGF-A(164) (Ad-VEGF-A(164)) or with VEGF-A-secreting TA3/St mammary tumors. We found that MV formation resulted from greatly increased activity of cathepsins (B>S>L) in venules transitioning into MV, as well as from a reciprocal decrease in the expression of several cysteine protease inhibitors (CPI), stefin A and cystatins B and C, by these same venules. Using a fluorescence probe that selectively binds cellular sites of cathepsin protease activity in vivo, we showed that increased cathepsin activity was localized exclusively to perivenular cells, not to venule endothelial cells. CPI strikingly inhibited angiogenesis in the Matrigel assay, and Ad-VEGF-A(164)-induced angiogenesis was reduced by approximately 50% in cathepsin B-null mice. Thus, VEGF-A, whether expressed by interstitial cells infected with an adenoviral vector or by tumor cells, upsets the normal cathepsin-CPI balance in nearby venules, leading to degradation of their basement membranes, an important first step in angiogenesis.

Rapamycin-insensitive up-regulation of MMP2 and other genes in tuberous sclerosis complex 2-deficient lymphangioleiomyomatosis-like cells

Increased matrix metalloproteinase (MMP) activity has been implicated in the pathogenesis of lymphangioleiomyomatosis (LAM). The objective of this study was to investigate how tuberous sclerosis complex (TSC) 1 or TSC2 deficiency alters MMP expression and regulation. We studied immortalized cells that lack TSC2 derived from an angiomyolipoma of a patient with LAM, a TSC2 addback derivative, and murine embryonic fibroblast cells that lack Tsc1 or -2 and respective controls. Global gene expression analysis was performed in the angiomyolipoma and derivative cell lines. MMP levels in the conditioned media from these cells were analyzed by zymography and ELISA. We found increased MMP-2 expression in cells lacking TSC1/TSC2 compared with their respective controls by zymography. MMP-2 overproduction by these cells was not affected by rapamycin treatment. Gene expression analysis confirmed increased MMP-2 gene expression that was not affected by rapamycin. Furthermore, multiple other genes were found to be overexpressed in rapamycin-treated TSC2-deficient cells compared with TSC2(+) cells. We conclude that TSC1/TSC2 deficiency leads to MMP-2 overproduction that is rapamycin-insensitive, and that several genes exhibit similar patterns, suggesting that TSC1/TSC2-dependent, but mammalian target of rapamycin-independent, pathways may be involved in the pathogenesis of LAM.

Tumor-specific urinary matrix metalloproteinase fingerprinting: identification of high molecular weight urinary matrix metalloproteinase species

PURPOSE

We have previously reported that matrix metalloproteinases MMP-2, MMP-9, and the complex MMP-9/NGAL can be detected in urine of patients with a variety of cancers including prostate and bladder carcinoma. In addition, we also detected several unidentified urinary gelatinase activities with molecular weights >125 kDa. The objective of the current study was to identify these high molecular weight (HMW) species, determine their potential as predictors of disease status, and ask whether a tumor-specific pattern existed based on urinary MMP analysis.

EXPERIMENTAL DESIGN

Chromatography, zymography, and mass spectrometry was used to identify HMW gelatinase species of approximately 140, 190, and >220 kDa in urine of cancer patients. To determine whether a tumor-specific pattern of appearance existed among the MMPs detected, we analyzed the urine of 189 patients with prostate or bladder cancer and controls.

RESULTS

The approximately 140, >220 kDa, and approximately 190 HMW gelatinase species were identified as MMP-9/tissue inhibitor of metalloproteinase 1 complex, MMP-9 dimer, and ADAMTS-7, respectively. The frequency of detection of any MMP species was significantly higher in urine from prostate and bladder cancer groups than controls. MMP-9 dimer and MMP-9 were independent predictors for distinguishing between patients with prostate and bladder cancer (P < 0.001 for each) by multivariable analysis.

CONCLUSIONS

This study is the first to identify a tumor-specific urinary MMP fingerprint that may noninvasively facilitate identification of cancer presence and type. This information may be of diagnostic and prognostic value in the detection and/or clinical monitoring of disease progression and therapeutic efficacy in patients with bladder or prostate cancer.

Ovarian cancer biomarkers: current options and future promise

As more effective, less toxic cancer drugs reach patients, the need for accurate and reliable cancer diagnostics and prognostics has become widely appreciated. Nowhere is this need more dire than in ovarian cancer; here most women are diagnosed late in disease progression. The ability to sensitively and specifically predict the presence of early disease and its status, stage, and associated therapeutic efficacy has the potential to revolutionize ovarian cancer detection and treatment. This article reviews current ovarian cancer diagnostics and prognostics and potential biomarkers that are being studied and validated. Some of the most recent molecular approaches being used to identify genes and proteins are presented, which may represent the next generation of ovarian cancer diagnostics and prognostics.

Urinary metalloproteinases: noninvasive biomarkers for breast cancer risk assessment

Matrix metalloproteinases (MMP) and a disintegrin and metalloprotease 12 (ADAM 12) can be detected in the urine of breast cancer patients and provide independent prediction of disease status. To evaluate the potential of urinary metalloproteinases as biomarkers to predict breast cancer risk status, urine samples from women with known risk marker lesions, atypical hyperplasia and lobular carcinoma in situ (LCIS), were analyzed. Urine samples were obtained from 148 women: 44 women with atypical hyperplasia, 24 women with LCIS, and 80 healthy controls. MMP analysis was done using gelatin zymography and ADAM 12 analysis was done via immunoblotting with monospecific antibodies and subsequent densitometric measurement. Positive urinary MMP-9 levels indicated a 5-fold risk of atypical hyperplasia and >13-fold risk of LCIS compared with normal controls. Urinary ADAM 12 levels were significantly elevated in women with atypical hyperplasia and LCIS from normal controls, with receiver operating characteristic curve analysis showing an area under the curve of 0.914 and 0.950, respectively. To assess clinical applicability, a predictive index was developed using ADAM 12 in conjunction with Gail risk scores for women with atypia. Scores above 2.8 on this ADAM 12-Gail risk prediction index score are predictive of atypical hyperplasia (sensitivity, 0.976; specificity, 0.977). Our data suggest that the noninvasive detection and analysis of urinary ADAM 12 and MMP-9 provide important clinical information for use as biomarkers in the identification of women at increased risk of developing breast cancer.