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Despite the great advances in autophagy research in the last years, the specific functions of the four mammalian Atg4 proteases (ATG4A-D) remain unclear. In yeast, Atg4 mediates both Atg8 proteolytic activation, and its delipidation. However, it is not clear how these two roles are distributed along the members of the ATG4 family of proteases. We show that these two functions are preferentially carried out by distinct ATG4 proteases, being ATG4D the main delipidating enzyme. In mammalian cells, ATG4D loss results in accumulation of membrane-bound forms of mATG8s, increased cellular autophagosome number and reduced autophagosome average size. In mice, ATG4D loss leads to cerebellar neurodegeneration and impaired motor coordination caused by alterations in trafficking/clustering of GABAA receptors. We also show that human gene variants of ATG4D associated with neurodegeneration are not able to fully restore ATG4D deficiency, highlighting the neuroprotective role of ATG4D in mammals.

BackgroundMechanical stretch of cancer cells can alter their invasiveness. During mechanical ventilation, lungs may be exposed to an increased amount of stretch, but the consequences on lung tumours have not been explored.MethodsTo characterise the influence of mechanical ventilation on the behaviour of lung tumours, invasiveness assays and transcriptomic analyses were performed in cancer cell lines cultured in static conditions or under cyclic stretch. Mice harbouring lung melanoma implants were submitted to mechanical ventilation and metastatic spread was assessed. Additional in vivo experiments were performed to determine the mechanodependent specificity of the response. Incidence of metastases was studied in a cohort of lung cancer patients that received mechanical ventilation compared with a matched group of nonventilated patients.ResultsStretch increases invasiveness in melanoma B16F10luc2 and lung adenocarcinoma A549 cells. We identified a mechanosensitive upregulation of pathways involved in cholesterol processing in vitro, leading to an increase in pro-protein convertase subtilisin/kexin type 9 (PCSK9) and LDLR expression, a decrease in intracellular cholesterol and preservation of cell stiffness. A course of mechanical ventilation in mice harbouring melanoma implants increased brain and kidney metastases 2 weeks later. Blockade of PCSK9 using a monoclonal antibody increased cell cholesterol and stiffness and decreased cell invasiveness in vitro and metastasis in vivo. In patients, mechanical ventilation increased PCSK9 abundance in lung tumours and the incidence of metastasis, thus decreasing survival.ConclusionsOur results suggest that mechanical stretch promote invasiveness of cancer cells, which may have clinically relevant consequences. Pharmacological manipulation of cholesterol endocytosis could be a novel therapeutic target in this setting.

Different microRNAs (miRNAs), including miR-29 family, may play a role in the development of heart failure (HF), but the underlying molecular mechanisms in HF pathogenesis remain unclear. We aimed at characterizing mice deficient in miR-29 in order to address the functional relevance of this family of miRNAs in the cardiovascular system and its contribution to heart disease. In this work, we show that mice deficient in miR-29a/b1 develop vascular remodeling and systemic hypertension, as well as HF with preserved ejection fraction (HFpEF) characterized by myocardial fibrosis, diastolic dysfunction, and pulmonary congestion, and die prematurely. We also found evidence that the absence of miR-29 triggers the up-regulation of its target, the master metabolic regulator PGC1α, which in turn generates profound alterations in mitochondrial biogenesis, leading to a pathological accumulation of small mitochondria in mutant animals that contribute to cardiac disease. Notably, we demonstrate that systemic hypertension and HFpEF caused by miR-29 deficiency can be rescued by PGC1α haploinsufficiency, which reduces cardiac mitochondrial accumulation and extends longevity of miR-29–mutant mice. In addition, PGC1α is overexpressed in hearts from patients with HF. Collectively, our findings demonstrate the in vivo role of miR-29 in cardiovascular homeostasis and unveil a novel miR-29/PGC1α regulatory circuitry of functional relevance for cell metabolism under normal and pathological conditions., Author summary To combat diseases, we first need to gain knowledge on how cells function at the molecular level to maintain normal physiology. One great scientific achievement of the last decade was the identification of thousands of small regulatory RNA molecules, called microRNAs. Strikingly, each microRNA has the potential to fine-tune the expression of hundreds of target genes depending on the spatiotemporal context. Therefore, defects in key microRNAs can contribute to the development of diseases. In the present work, we characterize the role for miR-29 in cardiac function in a mouse model. We found that mice deficient for miR-29 develop life-threatening cardiometabolic alterations that subsequently cause heart failure with diastolic dysfunction and systemic hypertension. We also demonstrate that these pathological phenotypes originate in part by the anomalous up-regulation of the transcriptional coactivator PGC1α, which can lead to mitochondrial hyperplasia in the heart. Genetic removal of one copy of PGC1α significantly attenuated the severity of the cardiovascular phenotype observed in miR-29–deficient mice. In addition, we show that PGC1α expression is misregulated in heart failure patients, suggesting that the implementation of miR-29 replacement therapy could potentially be used to treat these fatal pathologies.

Matrix metalloproteinases (MMPs) have been implicated in a variety of human diseases, including neuroimmunological disorders such as multiple sclerosis. However, the recent finding that some MMPs play paradoxical protective roles in these diseases has made necessary the detailed study of the specific function of each family member in their pathogenesis. To determine the relevance of collagenase-2 (MMP-8) in experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis, we have performed two different analyses involving genetic and biochemical approaches. First, we have analyzed the development of EAE in mutant mouse deficient in MMP-8, with the finding that the absence of this proteolytic enzyme is associated with a marked reduction in the clinical symptoms of EAE. We have also found that MMP-8-/- mice exhibit a marked reduction in central nervous system-infiltrating cells and demyelinating lesions. As a second approach, we have carried out a pharmacological inhibition of MMP-8 with a selective inhibitor against this protease (IC50 = 0.4 nm). These studies have revealed that the administration of the MMP-8 selective inhibitor to mice with EAE also reduces the severity of the disease. Based on these findings, we conclude that MMP-8 plays an important role in EAE development and propose that this enzyme may be a novel therapeutic target in human neuro-inflammatory diseases such as multiple sclerosis.

MT1‐MMP ( MMP14 ) is a collagenolytic enzyme located at the cell surface and implicated in extracellular matrix (ECM) remodeling. Mmp14 −/− mice present dwarfism, bone abnormalities, and premature death. We demonstrate herein that the loss of MT1‐MMP also causes cardiac defects and severe metabolic changes, and alters the cytoskeleton and the nuclear lamina structure. Moreover, the absence of MT1‐MMP induces a senescent phenotype characterized by up‐regulation of p16 INK 4a and p21 CIP 1/ WAF 1 , increased activity of senescence‐associated β‐galactosidase, generation of a senescence‐associated secretory phenotype, and somatotroph axis alterations. Consistent with the role of retinoic acid signaling in nuclear lamina stabilization, treatment of Mmp14 −/− mice with all‐ trans retinoic acid reversed the nuclear lamina alterations, partially rescued the cell senescence phenotypes, ameliorated the pathological defects in bone, skin, and heart, and extended their life span. These results demonstrate that nuclear architecture and cell senescence can be modulated by a membrane protease, in a process involving the ECM as a key regulator of nuclear stiffness under cell stress conditions.

Matrix metalloproteinases (MMPs) have been traditionally implicated in cancer progression because of their ability to degrade the extracellular matrix. However, some members of the MMP family have recently been identified as proteases with antitumor properties. Thus, it has been described that collagenase-2 (MMP-8) has a protective role in tumor and metastasis progression, but the molecular mechanisms underlying these effects are unknown. We show herein that Mmp8 expression causes a decrease in miR-21 levels that in turn leads to a reduction in tumor growth and lung metastasis formation by MDA-MB-231 (4175) breast cancer cells. By using both in vitro and in vivo models, we demonstrate that the mechanism responsible for these MMP-8 beneficial effects involves cleavage of decorin by MMP-8 and a subsequent reduction of transforming growth factor β (TGF-β) signaling that controls miR-21 levels. In addition, miR-21 downregulation induced by MMP-8 increases the levels of tumor suppressors such as programmed cell death 4, which may also contribute to the decrease in tumor formation and metastasis of breast cancer cells overexpressing this metalloproteinase. These findings reveal a new signaling pathway for cancer regulation controlled by MMP-8, and contribute to clarify the molecular mechanisms by which tumor-defying proteases may exert their protective function in cancer and metastasis.

Keeping Cancer Cells At Bay Cancer cells are often aneuploid; that is, they have an abnormal number of chromosomes. But to what extent this contributes to the tumorigenic phenotype is not clear. Senovilla et al. (p. 1678 ; see the Perspective by Zanetti and Mahadevan ) found that tetraploidization of cancer cells can cause them to become immunogenic and thus aid in their clearance from the body by the immune system. Cells with excess chromosomes put stress on the endoplasmic reticulum, which leads to movement of the protein calreticulin to the cell surface. Calreticulin exposure in turn caused recognition of cancer cells in mice by the host immune system. Thus, the immune system appears to serve a protective role in eliminating hyperploid cells that must be overcome to allow unrestricted growth of cancer cells.

High-pressure ventilation triggers different inflammatory and matrix remodeling responses within the lung. Although some of them may cause injury, the involvement of these mediators in repair is largely unknown. To identify mechanisms of repair after ventilator-induced lung injury (VILI), mice were randomly assigned to baseline conditions (no ventilation), injury [90 min of high-pressure ventilation without positive end-expiratory pressure (PEEP)], repair (injury followed by 4 h of low-pressure ventilation with PEEP), and ventilated controls (low-pressure ventilation with PEEP for 90 and 330 min). Histological injury and lung permeability increased during injury, but were partially reverted in the repair group. This was accompanied by a proinflammatory response, together with increases in TNF-α and IFN-γ, which returned to baseline during repair, and a decrease in IL-10. However, macrophage inflammatory protein-2 (MIP-2) and matrix metalloproteinases (MMP)-2 and -9 increased after injury and persisted in being elevated during repair. Mortality in the repair phase was 50%. Survivors showed increased cell proliferation, lower levels of collagen, and higher levels of MIP-2 and MMP-2. Pan-MMP or specific MMP-2 inhibition (but not MIP-2, TNF-α, or IL-4 inhibition) delayed epithelial repair in an in vitro wound model using murine or human alveolar cells cultured in the presence of bronchoalveolar lavage fluid from mice during the repair phase or from patients with acute respiratory distress syndrome, respectively. Similarly, MMP inhibition with doxycycline impaired lung repair after VILI in vivo. In conclusion, VILI can be reverted by normalizing ventilation pressures. An adequate inflammatory response and extracellular matrix remodeling are essential for recovery. MMP-2 could play a key role in epithelial repair after VILI and acute respiratory distress syndrome.

Contains fulltext : 69166.pdf (Publisher’s version ) (Closed access) Collagenase-2 (matrix metalloproteinase-8, MMP-8) is an MMP mainly produced by neutrophils and associated with many inflammatory conditions. We have previously described that MMP-8 plays a protective role in cancer through its ability to regulate the inflammatory response induced by carcinogens. Moreover, it has been reported that experimental manipulation of the expression levels of this enzyme alters the metastatic behavior of human breast cancer cells. In this work, we have used mutant mice deficient in MMP-8 and syngenic melanoma and lung carcinoma tumor cells lines overexpressing this enzyme to further explore the putative antimetastatic potential of MMP-8. We report herein that MMP-8 prevents metastasis formation through the modulation of tumor cell adhesion and invasion. Thus, tumor cells overexpressing MMP-8 have an increased adhesion to extracellular matrix proteins, whereas their invasive ability through Matrigel is substantially reduced when compared with control cells. Analysis of MMP-8 in breast cancer patients revealed that the expression of this metalloproteinase by breast tumors correlates with a lower incidence of lymph node metastasis and confers good prognosis to these patients. On this basis, we propose that MMP-8 is a tumor protective factor, which also has the ability to reduce the metastatic potential of malignant cells in both mice and human.

The Trefoil Factor 1 (TFF1/pS2), a peptide consisting of 60 amino acids, is the most abundant estrogen-induced messenger RNA present in MCF-7 breast cancer cells. The objective of this work was to evaluate the cytosolic TFF1 content in breast carcinomas, its possible relationship with different clinical-pathological parameters, and its potential prognostic significance and predictive value.Cytosolic TFF1 levels were examined by immunoradiometric assay in 1031 patients with invasive breast cancer. The median follow-up period was of 50 months.There was a wide variability of cytosolic TFF1 levels in tumors (0.9-743.2 ng/mg protein). Statistical analysis showed that TFF1 levels were significantly higher in premenopausal patients (p = 0.001), as well as in tumors showing any of the following characteristics: good differentiation (p = 0.0001), ER and PgR positivity (p = 0.0001 and p = 0.001, respectively), diploidy (p = 0.045) and a high S-phase fraction (p = 0.001). In addition, the presence of high intratumoral TFF1 levels (cut-off: 2 ng/mg protein) was independently associated with a shorter overall survival in the group of patients as a whole (p = 0.001) as well as in the subgroup with node-negative breast cancer (p = 0.0004). Likewise, high intratumoral TFF1 levels were associated with a more prolonged overall survival in patients who received adjuvant tamoxifen (p = 0.004).In breast cancer patients, intratumoral TFF1 levels are associated with a better clinical outcome, especially in those with node-negative tumors. In addition, TFF1 levels have a low but significant predictive value in regards to response to adjuvant therapy with tamoxifen.

Purpose: Retrospective analysis to assess the prognostic and predictive value of HER-2/ neu expression in breast tumors, quantified by enzyme immunoassay (ELISA).Methods: Quantification of HER-2/neu was performed on cytosolic extracts from 914 cases of primary invasive breast carcinomas. Relapse-free and overall survival data were available from 889 patients. The prognostic value of HER-2/neu levels was assessed considering them as a continuous, dichotomic or quartile variable.Results: Cytosolic HER-2/neu levels ranged widely in breast carcinomas (median: 746.5 NHU/mg; range: 2.8–80,000 NHU/mg protein). HER-2/neu protein levels were significantly higher in either moderately or poorly differentiated tumors, as well as in those showing a ductal histological type, aneuploidy or a high S-phase fraction. There was a significant and positive association between cytosolic and membranous HER-2/neu levels (n=162, r sub S=0.53; P Q 3), we observed that patients with either low HER-2/ neu levels (≤ Q 1) or high HER-2/neu levels (> Q 3) had shorter both relapse-free survival and overall survival curves than those patients with intermediate HER-2/neu levels. On the other hand, high HER-2/neu levels predicted a poor response to adjuvant chemotherapy but not to adjuvant hormonal therapy with tamoxifen.Conclusions: The results of the present investigation indicate that by quantitatively determining the content of HER-2/neu oncoprotein, groups of high-risk breast cancer patients could be identified, for a more effective clinical management.

Remodeling of fibrillar collagen in mouse tissues has been widely attributed to the activity of collagenase-3 (matrix metalloproteinase-13 (MMP-13)), the main collagenase identified in this species. This proposal has been largely based on the repeatedly unproductive attempts to detect the presence in murine tissues of interstitial collagenase (MMP-1), a major collagenase in many species, including humans. In this work, we have performed an extensive screening of murine genomic and cDNA libraries using as probe the full-length cDNA for human MMP-1. We report the identification of two novel members of the MMP gene family which are contained within the cluster of MMP genes located at murine chromosome 9. The isolated cDNAs contain open reading frames of 464 and 463 amino acids and are 82% identical, displaying all structural features characteristic of archetypal MMPs. Comparison for sequence similarities revealed that the highest percentage of identities was found with human interstitial collagenase (MMP-1). The new proteins were tentatively called Mcol-A and Mcol-B (Murinecollagenase-like A andB). Analysis of the enzymatic activity of the recombinant proteins revealed that both are catalytically autoactivable but only Mcol-A is able to degrade synthetic peptides and type I and II fibrillar collagen. Both Mcol-A and Mcol-Bgenes are located in the A1–A2 region of mouse chromosome 9, Mcol-A occupying a position syntenic to the human MMP-1 locus at 11q22. Analysis of the expression of these novel MMPs in murine tissues revealed their predominant presence during mouse embryogenesis, particularly in mouse trophoblast giant cells. According to their structural and functional characteristics, we propose that at least one of these novel members of the MMP family, Mcol-A, may play roles as interstitial collagenase in murine tissues and could represent a true orthologue of human MMP-1.

A cDNA encoding a new human matrix metalloproteinase (MMP), tentatively called MMP-23, has been cloned from an ovary cDNA library. This protein exhibits sequence similarity with MMPs, but displays a different domain structure. Thus, MMP-23 lacks a recognizable signal sequence and has a short prodomain, although it contains a single cysteine residue that can be part of the cysteine-switch mechanism operating for maintaining enzyme latency. The C-terminal domain is considerably shortened and shows no sequence similarity to hemopexin, whereas all human MMPs, with the exception of matrilysin, contain four hemopexin-like repeats. Furthermore, MMP-23 is devoid of structural features distinctive of the diverse MMP subclasses, including the specific residues located close to the zinc-binding site in collagenases, the transmembrane domain of membrane-type MMPs, or the fibronectin-like domain of gelatinases. Fluorescent in situ hybridization experiments showed that the human MMP-23 gene maps to 1p36, a location which differs from all MMP genes mapped to date. Recombinant MMP-23 produced in Escherichia coli exhibits low, but significant proteolytic activity against a synthetic substrate commonly used for assaying MMPs. Northern blot analysis demonstrated that MMP-23 is predominantly expressed in ovary, testis, and prostate, suggesting that this new MMP may play a specialized role in reproductive processes.

We have identified and characterized a novel human cysteine proteinase of the papain family. A full-length cDNA for this enzyme was cloned from a human brain cDNA library. Nucleotide sequence analysis revealed that the isolated cDNA codes for a polypeptide of 303 amino acids, tentatively called cathepsin Z, that exhibits structural features characteristic of cysteine proteinases. Fluorescent in situ hybridization experiments revealed that the human cathepsin Z gene maps to chromosome 20q13, a location that differs from all cysteine proteinase genes mapped to date. The cDNA encoding cathepsin Z was expressed in Escherichia coli as a fusion protein with glutathione S-transferase, and after purification, the recombinant protein was able to degrade the synthetic peptide benzyloxycarbonyl-Phe-Arg-7-amido-4-methylcoumarin, used as a substrate for cysteine proteinases. Northern blot analysis demonstrated that cathepsin Z is widely expressed in human tissues, suggesting that this enzyme could be involved in the normal intracellular protein degradation taking place in all cell types. Cathepsin Z is also ubiquitously distributed in cancer cell lines and in primary tumors from different sources, suggesting that this enzyme may participate in tumor progression as reported for other cathepsins. Finally, on the basis of a series of distinctive structural features, including diverse peptide insertions and an unusual short propeptide, together with its unique chromosomal location among cysteine proteinases, we propose that cathepsin Z may be the first representative of a novel subfamily of this class of proteolytic enzymes.

Critically ill patients frequently develop neuropsychological disturbances including acute delirium or memory impairment. The need for mechanical ventilation is a risk factor for these adverse events, but a mechanism that links lung stretch and brain injury has not been identified.To identify the mechanisms that lead to brain dysfunction during mechanical ventilation.Brains from mechanically ventilated mice were harvested, and signals of apoptosis and alterations in the Akt survival pathway were studied. These measurements were repeated in vagotomized or haloperidol-treated mice, and in animals intracerebroventricularly injected with selective dopamine-receptor blockers. Hippocampal slices were cultured and treated with micromolar concentrations of dopamine, with or without dopamine receptor blockers. Last, levels of dysbindin, a regulator of the membrane availability of dopamine receptors, were assessed in the experimental model and in brain samples from ventilated patients.Mechanical ventilation triggers hippocampal apoptosis as a result of type 2 dopamine receptor activation in response to vagal signaling. Activation of these receptors blocks the Akt/GSK3β prosurvival pathway and activates the apoptotic cascade, as demonstrated in vivo and in vitro. Vagotomy, systemic haloperidol, or intracerebroventricular raclopride (a type 2 dopamine receptor blocker) ameliorated this effect. Moreover, ventilation induced a concomitant change in the expression of dysbindin-1C. These results were confirmed in brain samples from ventilated patients.These results prove the existence of a pathogenic mechanism of lung stretch-induced hippocampal apoptosis that could explain the neurological changes in ventilated patients and may help to identify novel therapeutic approaches.

We generated mice deficient in Lon protease (LONP1), a major enzyme of the mitochondrial quality control machinery. Homozygous deletion of Lonp1 causes early embryonic lethality, whereas its haploinsufficiency protects against colorectal and skin tumors. Furthermore, LONP1 knockdown inhibits cellular proliferation and tumor and metastasis formation, whereas its overexpression increases tumorigenesis. Clinical studies indicate that high levels of LONP1 are a poor prognosis marker in human colorectal cancer and melanoma. Additionally, functional analyses show that LONP1 plays a key role in metabolic reprogramming by remodeling OXPHOS complexes and protecting against senescence. Our findings demonstrate the relevance of LONP1 for cellular and organismal viability and identify this protease as a central regulator of mitochondrial activity in oncogenesis. This work was supported by grants from the Ministerio de Economı´a y Competitividad, Instituto de Salud Carlos III (RTICC), and Red Tema´ tica de Investigacio´ n Cooperativa en Enfermedades Cardiovasculares. The Instituto Universitario de Oncologı´a is supported by Obra Social Cajastur. K.W. is supported by the Strategic Young Researcher Overseas Visits Program for Accelerating Brain Circulation from Japan Society for the Promotion of Science. C.L-O. is an investigator for the Botin Foundation. Sí

Alterations in the architecture and dynamics of the nuclear lamina have a causal role in normal and accelerated aging through both cell-autonomous and systemic mechanisms. However, the precise nature of the molecular cues involved in this process remains incompletely defined. Here we report that the accumulation of prelamin A isoforms at the nuclear lamina triggers an ATM- and NEMO-dependent signaling pathway that leads to NF-κB activation and secretion of high levels of proinflammatory cytokines in two different mouse models of accelerated aging (Zmpste24−/− and LmnaG609G/G609G mice). Causal involvement of NF-κB in accelerated aging was demonstrated by the fact that both genetic and pharmacological inhibition of NF-κB signaling prevents age-associated features in these animal models, significantly extending their longevity. Our findings provide in vivo proof of principle for the feasibility of pharmacological modulation of the NF-κB pathway to slow down the progression of physiological and pathological aging.

We report here the nucleotide (nt) sequence of a rat liver cDNA encoding Zn-alpha 2-glycoprotein (Zn-alpha 2-gp), a plasma protein with a high degree of sequence similarity to class-I major histocompatibility complex (MHC) antigens. The deduced amino acid (aa) sequence contains the coding information for 293 aa residues and shows 60% identity with the aa sequence of human Zn-alpha 2-gp and 35% identity with that corresponding to the extracellular domains of RT1, a rat class-I MHC antigen. Northern blot analysis showed that rat Zn-alpha 2-gp is expressed in liver, but not in a wide number of tissues, including prostate, mammary gland, kidney, intestine, lung, pancreas, ovary, uterus, thyroid, placenta, spleen, brain and heart.

Background. Tissue-type plasminogen activator (tPA) is a serine protease primarily involved in the intravascular dissolution of blood clots. High intratumoral tPA levels are associated with prognosis in several human tumors. In addition, tPA has been shown to be an estrogen-inducible protein in human breast cancer cell lines. The aim of the present study was to analyze the cytosolic tPA content in primary breast carcinomas and its potential clinical value. Materials and methods. tPA was measured by a solid-phase enzyme immunoassay in tumor cytosol samples obtained from 800 patients with breast cancer. The median follow-up period was of 49.2 months. Results. Cytosolic tPA levels ranged widely in breast carcinomas (median: 3.9; range: 0.1– 315.3 ng/mg protein). tPA levels were significantly lower in large tumors, as well as in those showing poor differentiation, estrogen (ER) or PgR-negativity, aneuploidy, or a high S-phase fraction. In addition, low tPA intratumoral levels were associated with a high probability of both shortened relapse-free and overall survival in all patients and in the subgroup with node-negative tumors. However, our results did not show any significant relationship between intratumoral tPA levels and prognosis in the different subgroups of patients, stratified according to the type of systemic adjuvant therapy received (chemotherapy, tamoxifen or chemotherapy plus sequential tamoxifen). Conclusion. The results of the present investigation indicate that low intratumoral tPA levels are associated with aggressiveness and poor prognosis in breast cancer patients. However, the study suggests that tPA levels do not predict response to systemic adjuvant therapy.

We have cloned and characterized a human brain cDNA encoding a new metalloprotease that has been called aminopeptidase O (AP-O). AP-O exhibits a series of structural features characteristic of aminopeptidases, including a conserved catalytic domain with a zinc-binding site (HEXXHX18E) that allows its classification in the M1 family of metallopeptidases or gluzincins. The structural complexity of AP-O is further increased by the presence of an additional C-terminal domain 170 residues long, which is predicted to have an ARM repeat fold originally identified in the Drosophila segment polarity gene product Armadillo. This ARM repeat domain is also present in aminopeptidase B, aminopeptidase B-like, and leukotriene A4 hydrolase and defines a novel subfamily of aminopeptidases that we have called ARM aminopeptidases. Northern blot analysis revealed that AP-O is mainly expressed in the pancreas, placenta, liver, testis, and heart. Human AP-O was produced in Escherichia coli, and the purified recombinant protein hydrolyzed synthetic substrates used for assaying aminopeptidase activity. This activity was abolished by general inhibitors of metalloproteases and specific inhibitors of aminopeptidases. Recombinant AP-O also cleaved angiotensin III to generate angiotensin IV, a bioactive peptide of the renin-angiotensin pathway with multiple actions on diverse tissues, including brain, testis, and heart. On the basis of these results we suggest that AP-O could play a role in the proteolytic processing of bioactive peptides in those tissues where it is expressed.

Cathepsin D (Cath-D) is an aspartyl protease involved in protein catabolism and tissue remodelling. In the present article, we evaluate the tumor content of Cath-D in resectable gastric carcinomas and its relation with clinical and pathological parameters, as well as its prognostic significance.This prospective study included a series of 60 patients with primary gastric adenocarcinoma, who first underwent a complete surgical resection of their tumors and then were evaluated for disease recurrence and survival status during a mean follow-up period of 41.5 months. Cath D was measured in cytosolic samples using an immune-radiometric assay which determined the total amount of Cath-D (52K, 48K, and 34K).The tumor content of Cath-D ranged from 4 to 247 pmol/mg protein and from 6.4 to 97.7 pmol/mg protein in adjacent non-neoplastic mucosa samples. Cytosolic Cath-D levels were significantly higher in neoplastic tissues (P0.001). Statistical analysis also demonstrated that younger patients showed lower Cath-D tumor levels than older ones. Likewise, patients with lower tumor levels of Cath-D had better survival than those with intermediate or high Cath-D tumor content (P = 0.002). This finding showed an independent prognostic value on survival (P = 0.02).The present study demonstrates the presence of higher Cath-D content in gastric carcinomas than in adjacent non-neoplastic mucosa, and that high intratumor Cath-D levels identify a subgroup of resectable gastric cancer patients with a high probability of relapse as well as worse survival.

Two cDNA clones coding for Zn-alpha 2-glycoprotein (Zn-alpha 2-gp) have been isolated from a human breast library and their nucleotide sequences determined. The deduced amino acid sequence contains the coding information for a hydrophobic signal peptide and the 278 residues of the mature protein. Comparison of this sequence with that from the protein purified from plasma reveals four differences: two amino acid changes (Gln-67 and Glu-222) and insertion of two residues (Ile-75 and Phe-76). Northern-blot analysis showed that the Zn-alpha 2-gp gene is expressed in liver and normal breast, but not in placenta, ovary and thyroid. A comparative analysis in mammary tissues from women with different diseases revealed enhanced expression of Zn-alpha 2-gp gene in benign breast lesions and a variable expression level in breast cancers.

The human gene (AZGP1) encoding Zn-[alpha][sub 2]-glycoprotein (Zn-[alpha][sub 2]-gp), a protein present in several biological fluids and produced by a subtype of breast carcinomas, has been cloned and its complete nucleotide sequence determined. The gene spans over 9.7 kb, and its overall organization and nucleotide sequence are very similar to those of the first four exons of class I MHC genes. However, the Zn-[alpha][sub 2]-gp gene differs from these genes in several significant ways. It lacks the coding information for the transmembrane and cytoplasmic domains typical of MHC genes, which is consistent with its presence as a soluble protein in different physiological and pathological fluids. In addition, it contains a high density of repetitive sequences, including Alu, MER, and MIR elements, which are not present at equivalent positions in class I MHC. Finally, its 5'-flanking region lacks the class I MHC regulatory complex and the interferon consensus sequence characteristic of class I MHC genes. These findings may explain the different expression pattern of Zn-[alpha][sub 2]-gp and class I MHC genes in human tissues. Southern blot hybridization of DNA from several species with a cDNA probe indicate that Zn-[alpha][sub 2]-gp genes are present in a wide variety of animal species, includingmore » monkey, rat, mouse, dog, cow, and rabbit. The human genome also contains a putative Zn-[alpha][sub 2]-gp pseudogene that has been isolated and partially characterized. This pseudogene has an intron-exon organization identical to that of the functional gene, but it presents two deleterious mutations in the third exon that lead to the appearance of premature stop codons. Finally, considering the lack of polymorphism in the Zn-[alpha][sub 2]-gp gene in comparison with MHC genes, putative roles for this human glycoprotein in the transport of nonpolymorphic substances or in intercellular recognition processes are proposed. 60 refs., 9 figs., 1 tab.« less

GCDFP(gross-cystic-disease-fluid protein)-24, a progesterone-binding protein present in large amounts in cyst fluid from human breast gross cystic disease, was purified in a one-step procedure by size-exclusion h.p.l.c. Peptide fragments obtained by trypsin digestion of the intact protein were purified by reverse-phase h.p.l.c. and analysed for their amino acid composition and subjected to automated Edman degradation. A search of the National Biomedical Research Foundation Data Bank revealed that all the sequenced tryptic peptides from protein GCDFP-24 matched perfectly with regions present in the amino acid sequence determined for human apolipoprotein D. Additional data on N-terminal sequence of the unblocked proteins, carbohydrate-attachment sites, amino acid composition and molecular-mass estimations supported the identity between both molecules. On the basis of this identity a possible role of apolipoprotein D in progesterone transport is proposed.

Serum prolactin (PRL) concentrations at baseline and after TRH stimulation were determined in 15 healthy women and in 51 premenopausal patients suffering from Gross Cystic Breast Disease. All women were in the luteal phase of the menstrual cycle and patients were divided into three groups according to cyst type at presentation. Basal hormone levels were within the normal range in the control group and in the three cystic breast disease groups. The maximum PRL response to TRH stimulation was significantly higher (p < 0.001) in patients with type I cysts (low Na+/K+ intracystic ratio and apocrine epithelium) than in patients with type II cysts (high Na+/K+ intracystic ratio and flattened epithelium), type III cysts (intermediate Na+/K+ intracystic ratio and mixed epithelium) and in normal women. Serum PRL concentrations corresponding to samples obtained 60 and 90 minutes after stimulation remained higher in the first group of patients. These results led us to consider the existence of an altered central regulation of PRL secretion in patients with type I cysts at presentation.

We used sodium dodecyl sulfate-polyacrylamide gel electrophoresis to study cyst fluids from women with breast gross cystic disease. The subjects could be classified into two categories according to the concentrations of protein GCDFP-70 in the cyst fluid: those with Type I cysts had a very low content of this protein; those with Type II cysts had very high concentrations. Analysis of the amino acid sequence of GCDFP-70 from both cyst fluid types confirmed that this protein is human plasma albumin. The average concentration of albumin found in Type I cyst fluids was 0.32 g/L and that corresponding to Type II was 10.16 g/L. Thus, albumin quantification from cyst fluids or analysis by either polyacrylamide or agarose gel electrophoresis provides a simple procedure for classifying these fluids, yielding results that correlate well with previous classifications based on other measurements such as sodium, potassium, and chloride concentrations. This albumin-based quantification method may improve the classification of breast cysts and might be useful in further studies on functional changes in the cysts and their relationship to breast cancer.

Collagenase-3 (MMP-13) is a recently identified member of the human matrix metalloproteinase gene family that is expressed in breast carcinomas and in articular cartilage from arthritic patients. Here, we have studied the cellular origin of this enzyme in breast carcinomas by in situ RNA hybridization, and we found that collagenase-3 is expressed by stromal cells immediately adjacent to epithelial tumor cells but not by the tumor cells themselves; nor is it expressed by the normal breast glandular epithelium. Consistent with this observation, coculture experiments using human fibroblasts and MCF-7 breast cancer cells revealed that conditioned medium from breast cancer cells stimulated the fibroblastic expression of collagenase-3 mRNA. In contrast, no stimulatory effect was observed when medium from fibroblast cells was added to breast cancer cells. These results strongly suggest that transcription of collagenase-3 in stromal cells is activated by diffusible factors released from epithelial breast cancer cells. A survey of a series of cytokines and growth factors known for their ability to induce collagenase-3 expression in human fibroblasts identified interleukin-1alpha and interleukin-1beta as potential candidates for inducing the expression of this MMP gene in breast carcinomas. According to these results, collagenase-3 should be included among the molecular factors that are detected during the stromal reaction to invasive breast cancer and that, by concerted action, may be essential for tumor growth and progression.