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Cascade events implicating PCs for tumor growth and metastasis. PCs control tumor cell adhesion by activating or and inducing the expression of adhesion molecules, regulate cell proliferation by activating growth factors, cytokines, and their receptors and induce migration and invasion of tumor cells that leads to metastases formation by activating MMPs 1.1 Role of the Proprotein Convertases in Tumor Cell Growth Usually, non-transformed cells show an absolute requirement for growth...

Role Of The Raserk Pathway In Furin Gene Regulation

Ras proteins are small G-proteins with GTPase activity that are located at the cytoplasmic membrane 38 . They are activated downstream of a variety of transmembrane receptors, a process that involves the exchange of GTP for GDP. Activated Ras represents an important signalling branchpoint because they activate several signalling pathways through a number of effectors that serve to regulate myriad of cell functions including growth, survival, differentiation, and angio-genesis. As important...

Discovery Of The Proprotein Convertases And Their Inhibitors

ABDEL-MAJID KHATIB1, NATHALIE SCAMUFFA1, FABIEN CALVO1, MICHEL CHR TIEN2 AND NABIL G. SEIDAH3 1INSERM U 716 AVENIR, Institut de G n tique Mol culaire, Paris, France 2 Regional Protein Chemistry Centre, Diseases of Ageing Unit, Ottawa Health Research Institute, Loeb Building, 725 Parkdale Ave., Ottawa, Ontario, Canada 3 Laboratory of Biochemical Neuroendocrinology, Institut de Recherches Cliniques de Montr al, 110 pine Ave West, Montreal, Quebec, Canada Abstract The members of the convertase...

Proprotein Convertases In Tumorigenesis Angiogenesis And Metastasis

The antitumor effect of PC inhibition was initially reported by our group. Expression of a 1-PDX in colon carcinoma HT-29 tumor cells delayed the appearance, the incidence and the vascularization of palpable tumors 20 . Subsequently, many studies have confirmed the inhibition of tumor growth by PC inhibition 31 . Accordingly, elevated expression of different PCs was reported for different human cancers and the levels of the proprotein convertase furin mRNA and protein expression correlate with...

Maturation of PDGFs

PDGFs are a pleotrophic family of growth factors that stimulate various cellular functions including growth, proliferation, and differentiation. The expression of PDGFs has been demonstrated in a number of different solid tumors, from glioblas-tomas to colon carcinomas 10-13 . In these various tumor types, the biologic role of PDGF signaling can vary from autocrine stimulation of cancer cell growth to paracrine interactions involving adjacent stroma and vasculature leading to tumor progression,...

Conclusion

Recent advances in the signalling pathway that regulates furin expression have uncovered a complex interplay between Smad, ERK and HIF-1 pathways. How these components impact on furin expression during tumor development and how they interconnect with other signalling networks will still need to be addressed. Furthermore, cancer-type-specific differences in the activity of these signalling pathways might predict variations within the levels of furin expression among tumors. Therefore, there is...

Acknowledgement

This work was supported by AVENIR Award, INSERM to AM K, Paris, France. REFERENCES 1 Siegfried G, Khatib AM, Benjannet S, Chretien M, Seidah NG (2003) The proteolytic processing of pro-platelet-derived growth factor-A at RRKR (86) by members of the proprotein convertase family is functionally correlated to platelet-derived growth factor-A-induced functions and tumorigenicity. Cancer Res 63 1458-1463 2 Siegfried G, Basak A, Cromlish JA, Benjannet S, Marcinkiewicz J, Chretien M, Seidah NG, Khatib...

PC1 and PC2

In an effort to find additional Furin-like enzymes, the polymerase chain reaction was used successfully to detect and amplify conserved sequences within the catalytic domain of Furin and Kex2. In 1990, Seidah et al., identified, in mouse pituitary, the cDNA of two additional PC-related enzymes that were called PC1 and PC2 15 . At approximately the same time, Smeekens and Steiner identified in human insulinoma a cDNA coding for PC2 16 . The human and mouse PC1 genes (PCSK1) are localized on...

Role Of The Smad Pathway In Furin Gene Regulation

In the last few years, significant progress has been made in elucidating the signalling mechanisms utilized by TGFp. A major discovery comes from the recent uncovering and cloning of specific Smad signalling proteins that consist in pathway-restricted Smads (Smad2 and Smad3), the common mediator Smad4, and the inhibitory Smads (Smad6 and Smad7) 25-27 that directly inhibit the TGFp type I receptor serine-threonine kinase and its transcriptional effectors. TGFp signals through sequential...

Biology Of Epithelial Ovarian Cancer

In this chapter we will restrict our discussion to EOC and will not discuss ovarian germ cell tumors or stromal tumors, which occur less frequently than EOC. EOC is comprised of five distinct histological subtypes (serous, clear cell, endometrioid, mucinous, and transitional) with serous adenocarcinomas occurring most frequently (Figure 1). There is considerable debate regarding the origin of EOC, but it is believed that greater than 90 of ovarian tumors arise from the cells covering the...

Table Of Contents

Chapter 1 Discovery of the Proprotein Convertases and their Abdel-Majid Khatib, Nathalie Scamuffa, Fabien Calvo, Michel Chr tien and Nabil G. Seidah Chapter 2 Signalling Pathways Leading to Furin Expression Stephanie McMahon and Claire M. Dubois Chapter 3 PACE4 Gene Expression in Human Ovarian Cancer 47 Brigitte L. Th riault, Yangxin Fu, Shawn K. Murray and Mark W. Nachtigal Chapter 4 Proprotein Convertases in Tumorigenesis, Angiogenesis Geraldine Siegfried, Michel Chr tien and Abdel-Majid...

Proprotein Convertases And Cancerrelated Substrates

Numerous cancer-related associated proteins are PC substrates. These substrates play significant roles in biological processes that are paramount to tumor promotion and progression, i.e. cell locomotion, adhesion, invasiveness and growth. The most salient substrate groups included in this chapter are those associated with cell to cell and cell to ECM interactions (collagens, integrins, cadherins) as well as those associated with ECM degradation (metalloproteinases). Other PC substrates that...

Subtilisin Kexinlike Isozyme1 SK1

In 1999, using reverse transcriptase-PCR and degenerate oligonucleotides, derived from the active-site residues of subtilisin kexin-like serine proteinases, we identified in human, rat, and mouse, a type I membrane-bound proteinase, which we called subtilisin kexin-isozyme-1 (SKI-1) 58 . It was so named because of the homology of its catalytic domain to the bacterial subtilisin BPN (Figure 4). In contrast to the basic amino acid-specific PCs, this convertase appears to prefer processing...

PC5 Isoforms PC5A and PC5B

The 915 amino acid isoform PC5A was identified and cloned by our group using RT-PCR and oligonucleotide sequences derived from conserved sequences of PC1, PC2, Furin, and PC4, in both mouse and rat tissues 41 . The same year, the group of Nakagawa et al., cloned this convertase and named it PC6 42 . The PC5 gene (PCSK5) is localized on human chromosome 9 and mouse chromosome 19 (Figure 3). The human PCSK5 gene encodes two isoforms the 915 amino acid PC5A and a C-terminally extended 1870-residue...

Unprocessed And Processed Neurotrophins Mediate Opposing Biological Action

Neurotrophic factors are a group of proteins with a similar structure that consists of nerve growth factor growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT-3) and neurotrophin 4 5 (NT-4 5) 55 . Initially, neurotrophins were described as important signaling molecules for the survival and neurite outgrowth of neurons 56 . Somewhat surprisingly, there is a growing body of evidence indicating that these molecules are also produced by various cancer cells and are...

Naturally Occurring PC1 Inhibitor ProSAAS

ProSAAS was identified by Fricker et al. during an analysis of peptides not properly processed in Cpefat Cpefat mice lacking carboxypeptidase E activity due to a point mutation in the carboxypeptidase E gene 79, 80 . These mice accumulate peptides with C-terminal Lys and or Arg extensions. Using an affinity column, peptides with C-terminal basic residues from Cpefat Cpefat tissues were isolated and analyzed. Five of these peptides were found to be encoded by proSAAS 81 . Subsequent...

Proprotein Convertases

The proprotein convertase (PC) family of calcium-dependent serine endoproteases plays a vital role in normal cellular physiology by converting proproteins to biologically active molecules. In mammals, nine PCs have been identified and cloned furin, PC1 3, PC2, PC4, PACE4, PC5 6, PC7, SKI-1 SIP 30-33 and NARC-1 34 . PCs are related to bacterial subtilisin, yeast kex2, and the C. elegans blisterase serine endoproteases that cleave precursor proteins at mono- and dibasic amino acid recognitions...

T t ft t t

Human PACE4 promoter is active in EOC cell lines. (A) The human PACE4 5'-flanking DNA and first exon have many putative transcription factor binding sites that include API, AP2, PEA3, SP1, and E-box binding sites for basis helix-loop-helix (bHLH) factors modified from Tsuji et al. 38 . +1 is defined as the start of transcription (indicated by horizontal arrow). The human PACE4 promoter and first exon (-827 to +314) was PCR amplified and subcloned into the pGL2.basic luciferase...

Furin Regulation By Hypoxia 81 Tumor Hypoxia

The tumor progression process is characterized by rapid cell growth accompanied by alterations in the microenvironment of the tumor cells. Among these changes, is the appearance of multiple areas of hypoxia (low oxygen tension), a hallmark feature of human and experimental tumors 40, 41 . Hypoxic regions within tumors arise for several reasons. First of all, rapid tumor cell growth can outpace the distance that allows adequate delivery of O2 by surrounding blood vessels, causing hypoxic areas...

List Of Contributors

Bioscan Continental Inc., 350, Industriel Boul., St-Eustache, Quebec J7R 5R4, Canada Diseases of Aging Program, Regional Protein Chemistry Center, Ottawa Health Research Institute, Loeb Building, 725 Parkdale Ave, Ottawa, ON K1Y 4K9 Department of Pathology, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA INSERM U 716 AVENIR, IGM, Rue Juliette Dodu, 75010, Paris, France Luis J. CNRS FRE2737, Facult de Pharmacie, 27 Bd J. Moulin, 13 385 Marseille Cedex 5, France Regional Protein...

Impact Of Tumor Microenvironment On Furin Expression

Over the recent years, a better understanding of the influence of the tumor microenvironment on furin expression has emerged. Until now, only few cancer related molecules were shown to modulate furin expression. Among others, the parathyroid hormone-related peptide (PTHrP), known to regulate the growth and invasion of human cancers such as breast, prostate, and lung cancer, enhances furin mRNA expression when added to human gastric cancer cell cultures. The transfection of furin cDNA within...

Animal Models

The use of animal models is emerging as a scientific necessity to confirm the role of PC's in mammalian tissues. The classical approach is the production of either transgenic mice overexpressing PCs or the ablation of the gene in knock-out models. Knocking down furin expression is lethal at early embryonic stages due to failure in heart development and other hemodynamic defects 89 . This study provided strong evidences favoring the non-redundancy in PCs activity, since this lethal phenotype...

Convertases Introductionstructure Of Integrins

Integrins are heterodimeric adhesion molecules that link the extracellular matrix to the actin cytoskeleton and signaling cascades. Integrins receive signals from other receptors, leading to the activation of ligand binding inside-out signaling and to matrix assembly. Upon binding ligands, integrins also activate intracellular signaling pathways outside-in signaling . In this way, cell adhesion is coordinated with other events to orchestrate complex cell behaviors, such as cell migration and or...

Exploiting Furin Signal Transduction Pathway For Anticancer Therapy

In many cancer types, elevated furin expression is associated with the development of a more aggressive phenotype, a process that was found to be blocked by the expression of furin-specific inhibitors within tumor xenografts 5, 72, 100 . In homeostasis, however, low expression levels of furin are found in cells and tissues, where this convertase is involved in the maturation of proproteins needed for normal cellular functions. For this reason, long term uncontrolled inhibition of such an enzyme...

Western Blot Analysis

Hplc Antibody

Concentrated media from AtT20 cells expressing either BDNF or gp160 in presence or absence of SEA were applied to a 13-22 T, 2.7 C gradient SDS-PAGE and western blot analysis were performed as described in 44-48 . Blots were probed with antibodies raised against mature BDNF or gp 120. After four washes 10 min each in Tris buffered saline containing 0.1 Tween-20, the primary antibody was visualized using horse radish peroxidase-coupled donkey antirabbit antibodies Jackson Immuno Research...

Introduction

Proteolytic processing of larger inactive precursor proteins into smaller functionally bioactive forms is an important cellular event implicated in both normal and abnormal human pathophysiology. This hypothesis of precursor processing originally advanced more than three decades ago 1,2 , was substantiated by numerous research publications reviewed in 3 . Because of this role, proteolytic enzymes remain in the forefront as important therapeutic targets for intervention of many diseases and...