Cecilia A. Fernandez

Matrix Metalloproteinase-3 Releases Active Heparin-binding EGF-like Growth Factor by Cleavage at a Specific Juxtamembrane Site

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is synthesized as a membrane-anchored precursor that is cleaved to release the soluble mature growth factor. The two forms are active as juxtacrine and paracrine/autocrine growth factors, respectively. The enzymes that process the HB-EGF transmembrane form are unknown. Accordingly, an in vitro assay was established using a fusion protein in which alkaline phosphatase (AP) replaced the transmembrane and cytoplasmic domains of HB-EGF (HB-EGF JM-AP). The fusion protein was anchored to agarose beads coated with anti-AP antibodies. Several matrix metalloproteinases (MMPs) were tested for the ability to release soluble HB-EGF in the in vitrosystem. MMP-3 released soluble 12-kDa immunoreactive and mitogenic HB-EGF within 30 min. On the other hand neither MMP-2 nor MMP-9 had any cleavage activities. A non-cleavable mutant was prepared by replacing the juxtamembrane (JM) region of HB-EGF with the JM region of CD4. The mutant HB-EGF, which in its full-length form was as active a juxtacrine growth factor as was the wild type HB-EGF in vivo, was not cleaved by MMP-3 in the in vitro assay. The C-terminal portion of the cleaved HB-EGF JM-AP that remained attached to the anti-AP beads was N-terminally sequenced and the MMP-3 cleavage site was determined to be Glu151-Asn152, a site within the JM domain. MMP-3 treatment also released soluble HB-EGFin vivo from MC2 cells expressing transmembrane HB-EGF precursor, at a level of about 2-fold above control. It was concluded that MMP-3 cleaves HB-EGF at a specific site in the JM domain and that this enzyme might regulate the conversion of HB-EGF from being a juxtacrine to a paracrine/autocrine growth factor.

The matrix metalloproteinase-9/neutrophil gelatinase-associated lipocalin complex plays a role in breast tumor growth and is present in the urine of breast cancer patients

Purpose: Having previously shown that the binding of neutrophil gelatinase-associated lipocalin (NGAL) to matrix metalloproteinase-9 (MMP-9) protects this extracellular matrix remodeling enzyme from autodegradation, we hypothesized that the addition of NGAL to breast cancer cells, which do not express this protein but do express MMP-9, might result in a more aggressive phenotype in vivo. Based on our previous reports that MMPs can be detected in the urine of cancer patients, we also asked whether MMP-9/NGAL could be detected in the urine of breast cancer patients and whether it might be predictive of disease status. Experimental Design: Clones of MCF-7 human breast cancer cells differentially expressing NGAL were generated by stable transfection with human NGAL expression constructs. The established clones were then implanted s.c. in immunodeficient mice and tumor growth was monitored. In addition, we analyzed the urine of individuals with breast cancer and age-matched, sex-matched controls using gelatin zymography for the presence of MMP-9/NGAL. Results: Increased NGAL expression resulted in significant stimulation of tumor growth. Immunohistochemical analysis of MCF-7 tumors revealed that the NGAL-overexpressing ones exhibited increased growth rates that were accompanied by increased levels of MMP-9, increased angiogenesis, and an increase in the tumor cell proliferative fraction. In addition, MMP-9/NGAL complex was detected in 86.36% of the urine samples from breast cancer patients but not in those from healthy age and sex-matched controls. Conclusions: These findings suggest, for the first time, that NGAL may play an important role in breast cancer in vivo by protecting MMP-9 from degradation thereby enhancing its enzymatic activity and facilitating angiogenesis and tumor growth. Clinically, these data suggest that the urinary detection of MMP-9/NGAL may be useful in noninvasively predicting disease status of breast cancer patients.

Structural and functional uncoupling of the enzymatic and angiogenic inhibitory activities of tissue inhibitor of metalloproteinase-2 (TIMP-2): loop 6 is a novel angiogenesis inhibitor.

Tissue inhibitors of metalloproteinases (TIMPs) regulate tumor growth, progression, and angiogenesis in a variety of experimental cancer models and in human malignancies. Results from numerous studies have revealed important differences between TIMP family members in their ability to inhibit angiogenic processes in vitro and angiogenesis in vivo despite their universal ability to inhibit matrix metalloproteinase (MMP) activity. To address these differences, a series of structure-function studies were conducted to identify and to characterize the anti-angiogenic domains of TIMP-2, the endogenous MMP inhibitor that uniquely inhibits capillary endothelial cell (EC) proliferation as well as angiogenesis in vivo. We demonstrate that the COOH-terminal domain of TIMP-2 (T2C) inhibits the proliferation of capillary EC at molar concentrations comparable with those previously reported for intact TIMP-2, while the NH2-terminal domain (T2N), which inhibits MMP activity, has no significant anti-proliferative effect. Interestingly, although both T2N and T2C inhibited embryonic angiogenesis, only T2C resulted in the potent inhibition of angiogenesis driven by the exogenous addition of angiogenic mitogen, suggesting that MMP inhibition alone may not be sufficient to inhibit the aggressive neovascularization characteristic of aberrant angiogenesis. We further mapped the anti-proliferative activity of T2C to a 24-amino acid peptide corresponding to Loop 6 of TIMP-2 and show that Loop 6 is a potent inhibitor of both embryonic and mitogen-stimulated angiogenesis in vivo. These findings demonstrate that TIMP-2 possesses two distinct types of anti-angiogenic activities which can be uncoupled from each other, the first represented by its MMP-dependent inhibitory activity which can inhibit only embryonic neovascularization and the second represented by an MMP-independent activity which inhibits both normal angiogenesis and mitogen-driven angiogenesis in vivo. In addition, we report, for the first time, the discovery of Loop 6 as a novel and potent inhibitor of angiogenesis.

Bone morphogenetic protein 1 processes prolactin to a 17-kDa antiangiogenic factor

In addition to classical expression patterns in pituitary and placenta and functions in growth and reproduction, members of the small family of hormones that includes prolactin (PRL), growth hormone (GH), and placental lactogen are expressed by endothelia and have angiogenic effects. In contrast, 16- to 17-kDa proteolytic fragments of these hormones have antiangiogenic effects. Here we show that PRL and GH are bound and processed by members of the bone morphogenetic protein 1 (BMP1) subgroup of extracellular metalloproteinases, previously shown to play key roles in forming extracellular matrix and in activating certain TGFβ superfamily members. BMP1 has previously been suggested to play roles in angiogenesis, as high throughput screens have found its mRNA to be one of those induced to highest levels in tumor-associated endothelia compared with resting endothelia. PRL and GH cleavage is shown to occur in each hormone at a single site typical of sites previously characterized in known substrates of BMP1-like proteinases, and the ≈17-kDa PRL N-terminal fragment so produced is demonstrated to have potent antiangiogenic activity. Mouse embryo fibroblasts are shown to produce both PRL and GH and to process them to ≈17-kDa forms, whereas GH and PRL processing activity is lost in mouse embryo fibroblasts doubly null for two genes encoding BMP1-like proteinases.

Fetal partial urethral obstruction causes renal fibrosis and is associated with proteolytic imbalance.

PURPOSE We determine whether fetal bladder outlet obstruction induces renal fibrosis, and is associated with an alteration in the regulation of connective tissue degradation and the presence of fibrogenic interstitial cells. MATERIALS AND METHODS Partial bladder outlet obstruction was surgically induced in 33 fetal sheep at 95 days of gestation. These animals and 24 normal age matched controls were sacrificed at 109, 116 and 135 (term) days of gestation, and the kidneys were rapidly retrieved, drained and weighed. Representative whole kidney samples were snap frozen for assessment of deoxyribonucleic acid, protein and collagen content. Morphometric analysis and alpha-smooth muscle actin immunohistochemistry were performed on histological specimens from formalin fixed kidneys. Tissue extract from fresh kidney specimens were analyzed for metalloproteinase and tissue inhibitor of metalloproteinase activity. Urine samples obtained at the time of sacrifice were analyzed for electrolyte, creatinine and N-acetyl glucosaminidase excretion. RESULTS All obstructed kidneys were hydronephrotic and larger than age matched controls. Obstructed kidneys at term showed interstitial fibrosis, as measured by increased extracellular matrix volume fraction (45% in male obstructed kidneys versus 2.5% in normal male kidneys, p = 0.0004), increased total collagen content (120 mg./kidney in male obstructed versus 20 mg. in normal male animals, p = 0.016) and collagen/deoxyribonucleic acid content per kidney (2.78 versus 0.53 mg./mg., p = 0.016). Metalloproteinase-1 activity was significantly lower in obstructed kidneys (210 versus 380 U./mg. protein in normal kidneys). Tissue inhibitor of metalloproteinase activity was undetectable in both groups. The presence of an increased population of myofibroblasts often associated with fibrotic processes was seen by alpha-smooth muscle actin staining which was localized to interstitial cells throughout the cortex in obstructed kidneys. CONCLUSIONS Fetal partial bladder outlet obstruction induces renal interstitial fibrosis as early as 2 weeks after obstruction. A possible mechanism for this process is a shift in proteolytic activity to reduce matrix degradation in obstructed kidneys. These changes might be mediated by the increased number of fibrogenic interstitial cells. The observations suggest several potential approaches to developing an understanding of congenital obstructive uropathy.

A Novel Approach to Using Matrix Metalloproteinases for Bladder Cancer

PURPOSE Given the steadily growing cancer survivor population, increasing pressure has been placed on more effective clinical approaches and biomarker assays to manage care. For bladder cancer despite the high probability of recurrence the number of patients with recurrent disease is significantly lower than the number that remains cancer free at any monitoring interval. We developed a noninvasive urine assay using a novel approach to identify patients without recurrent cancer with extremely high confidence. MATERIALS AND METHODS Previous studies show that matrix metalloproteinases are increased in the urine of patients with cancer compared to that in disease-free individuals. To determine the clinical usefulness of these markers as monitors for bladder cancer recurrence we measured and compared metalloproteinase-2, metalloproteinase-9 and metalloproteinase-9/neutrophil gelatinase-associated lipocalin by enzyme-linked immunosorbent assay and zymography in a set of 530 samples, including 84 samples from patients with bladder cancer. RESULTS Initial studies using urine metalloproteinase to discriminate disease-free patients from those with bladder cancer resulted in 80% sensitivity (67 of 84) and 71% specificity (318 of 446) for metalloproteinase-9. By applying our novel Clinical Intervention Determining Diagnostic() clinical approach to metalloproteinase-9 we correctly identified 42% of cases that were cystoscopy negative with 98% negative predictive value. CONCLUSIONS A noninvasive urine diagnostic assay that uses metalloproteinases with the Clinical Intervention Determining Diagnostic could lead to more efficient treatment in bladder cancer survivors by decreasing the number of negative cystoscopies (42%), allowing physicians to more selectively monitor those at high risk.

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.

A Noninvasive Multianalyte Urine-Based Diagnostic Assay for Urothelial Cancer of the Bladder in the Evaluation of Hematuria

OBJECTIVE To test whether a noninvasive urine-based multianalyte diagnostic readout assay that uses protein and DNA biomarkers can risk stratify patients with hematuria into those who are or are not likely to have bladder cancer and those who should receive standard care. PATIENTS AND METHODS This prospective, observational, multicenter, single-assessment study was conducted between June 12, 2009, and April 15, 2011. Eligible patients presented with hematuria and as part of their evaluation underwent cystoscopy. Urine samples were analyzed for the presence of mutant FGFR3 and quantified matrix metalloproteinase 2 and the hypermethylation of TWIST1 and NID2. A patients chance of having (positive predictive value [PPV]) or not having (negative predictive value [NPV]) cancer was determined by FGFR3 alone or by all 4 biomarkers, respectively. RESULTS Cystoscopy/biopsy diagnosed 690 of 748 patients as negative and 58 as positive for bladder cancer. Of 21 patients identified by FGFR3 as highly likely to have cancer, 20 were also positive by cystoscopy/biopsy, resulting in a PPV of 95.2% (20 of 21), with specificity of 99.9% (689 of 690). The 4-marker combination identified 395 patients as having a low likelihood of cancer. Of these, 56.2% (388 of 690) also had negative biopsy/cystoscopy findings, resulting in an NPV of 98.2% (388 of 395). In total, 416 of the 748 patients with hematuria (55.6%) were identified with extremely high NPV and PPV to have or not have bladder cancer. CONCLUSION This multianalyte assay accurately stratified patients with high confidence into those who likely do or do not have bladder cancer. This test was developed to enhance and not to eliminate referrals for urologic evaluation.

A noninvasive multi-analyte diagnostic assay: Combining protein and DNA markers to stratify bladder cancer patients

Purpose The authors recently reported the development of a noninvasive diagnostic assay using urinary matrix metalloproteinases (MMPs) as monitors of disease-free status and bladder cancer in high-risk populations. Using an approach called clinical intervention determining diagnostic (CIDD), they identified with high confidence those patients who could be excluded from additional intervention. To maximize performance, MMPs were combined with DNA-based markers and CIDD was applied to a population of patients undergoing monitoring for recurrence. Patients and methods Urine samples were obtained from 323 patients, 48 of whom had a recurrence and 275 of whom did not have cancer upon cytoscopic evaluation. Twist1 and Nid2 methylation status was determined using methylation-specific polymerase chain reaction, FGFR3 mutational status by quantitative PCR, and MMP levels by enzyme-linked immunosorbent assay. Results Using a combination of these DNA and protein markers, the authors identified with high confidence (97% negative predicted value) those patients who do not have cancer. Cutoffs were adjusted such that at 92% sensitivity, 51% of disease-free patients might be triaged from receiving further tests. Conclusion The multi-analyte diagnostic readout assay described here is the first to combine protein and DNA biomarkers into one assay for optimal clinical performance. Using this approach, the detection of FGFR3 mutations and Twist1 and Nid2 methylation in the urine of patients undergoing bladder cancer recurrence screening increase the sensitivity and negative predictive value at an established MMP protein cutoff. This noninvasive urinary diagnostic assay could lead to the more efficient triage of patients undergoing recurrence monitoring.

Matrilin-1 is an inhibitor of neovascularization

Background: The relative avascularity of cartilage has made it a promising source of angiogenesis inhibitors. Results: MATN-1, identified by mass spectrometry, suppresses capillary endothelial cell proliferation and migration. Conclusion: MATN-1 is a novel inhibitor of neovascularization in vivo and in vitro. Significance: This is the first demonstration that MATN-1 is an inhibitor of both normal and pathological 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.