Gene Summary

Gene:FURIN; furin, paired basic amino acid cleaving enzyme
Aliases: FUR, PACE, SPC1, PCSK3
Summary:This gene encodes a member of the subtilisin-like proprotein convertase family, which includes proteases that process protein and peptide precursors trafficking through regulated or constitutive branches of the secretory pathway. It encodes a type 1 membrane bound protease that is expressed in many tissues, including neuroendocrine, liver, gut, and brain. The encoded protein undergoes an initial autocatalytic processing event in the ER and then sorts to the trans-Golgi network through endosomes where a second autocatalytic event takes place and the catalytic activity is acquired. The product of this gene is one of the seven basic amino acid-specific members which cleave their substrates at single or paired basic residues. Some of its substrates include proparathyroid hormone, transforming growth factor beta 1 precursor, proalbumin, pro-beta-secretase, membrane type-1 matrix metalloproteinase, beta subunit of pro-nerve growth factor and von Willebrand factor. It is also thought to be one of the proteases responsible for the activation of HIV envelope glycoproteins gp160 and gp140 and may play a role in tumor progression. This gene is located in close proximity to family member proprotein convertase subtilisin/kexin type 6 and upstream of the FES oncogene. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2014]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Source:NCBIAccessed: 11 March, 2017


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 11 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Mice, Transgenic
  • Molecular Sequence Data
  • Amino Acid Sequence
  • Survival Rate
  • Promoter Regions
  • Disease Models, Animal
  • Western Blotting
  • Immunohistochemistry
  • Serine Endopeptidases
  • src-Family Kinases
  • Tumor Suppressor Proteins
  • Cancer Gene Expression Regulation
  • Tumor Burden
  • Breast Cancer
  • Protein Precursors
  • Translocation
  • Furin
  • bcl-2-Associated X Protein
  • HeLa Cells
  • Ultraviolet Rays
  • Cell Proliferation
  • Skin Cancer
  • Sequence Alignment
  • alpha 1-Antitrypsin
  • Transforming Growth Factor beta
  • Chromosome 15
  • Messenger RNA
  • Squamous Cell Carcinoma
  • p38 Mitogen-Activated Protein Kinases
  • Transfection
  • Lung Cancer
  • Proprotein Convertases
  • Base Sequence
  • Mutation
  • Neoplasm Invasiveness
  • Wound Healing
  • Cell Movement
  • Enzymologic Gene Expression Regulation
  • U937 Cells
Tag cloud generated 11 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (3)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: FURIN (cancer-related)

Meng P, Dong QC, Tan GG, et al.
Anti-tumor effects of a recombinant anti-prostate specific membrane antigen immunotoxin against prostate cancer cells.
BMC Urol. 2017; 17(1):14 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: To evaluate anti-prostate cancer effects of a chimeric tumor-targeted killer protein.
METHODS: We established a novel fusion gene, immunocasp-3, composed of NH2-terminal leader sequence fused with an anti-prostate-specific membrane antigen (PSMA) antibody (J591), the furin cleavage sequences of diphtheria toxin (Fdt), and the reverse coding sequences of the large and small subunits of caspase-3 (revcaspase-3). The expressing level of the immunocasp-3 gene was evaluated by using the reverse transcription-PCR (RT-PCR) and western blot analysis. Cell viability assay and cytotoxicity assay were used to evaluate its anti-tumor effects in vitro. Apoptosis was confirmed by electron microscopy and Annexin V-FITC staining. The antitumor effects of immunocasp-3 were assessed in nude mice xenograft models containing PSMA-overexpressing LNCaP cells.
RESULTS: This study shows that the immunocasp-3 proteins selectively recognized and induced apoptotic death in PSMA-overexpressing LNCaP cells in vitro, where apoptotic cells were present in 15.3% of the cells transfected with the immunocasp-3 expression vector at 48 h after the transfection, in contrast to 5.5% in the control cells. Moreover, LNCaP cells were significantly killed under the condition of the co-culture of the immunocasp-3-secreting Jurkat cells and more than 50% of the LNCaP cells died when the two cell lines were co-cultured within 5 days. In addition, The expression of immunocasp-3 also significantly suppressed tumor growth and greatly prolonged the animal survival rate in vivo.
CONCLUSION: A novel fusion gene, immunocasp-3, may represent a viable approach to treating PSMA-positive prostate cancer.

Nakajima K, Oiso S, Uto T, et al.
Triterpenes suppress octanoylated ghrelin production in ghrelin-expressing human gastric carcinoma cells.
Biomed Res. 2016; 37(6):343-349 [PubMed] Related Publications
Ghrelin is an appetite-stimulating peptide hormone with an octanoyl modification at serine 3 that is essential for its orexigenic effect. Ghrelin O-acyltransferase (GOAT) is the enzyme that catalyzes ghrelin acylation using fatty acyl-coenzyme A as a substrate. We previously developed an assay system based on the AGS-GHRL8 cell line that produces octanoylated ghrelin in the presence of octanoic acid, and demonstrated that some fatty acids suppressed octanoylated ghrelin production. Recent studies have reported that triterpenes have anti-obesity effect. Since such triterpenes, like fatty acids, have a carboxyl group, we speculated that they can suppress octanoylated ghrelin production. To test this hypothesis, we investigated the effect of triterpenes on octanoylated ghrelin production. Asiatic acid, corosolic acid, glycyrrhetinic acid, oleanolic acid and ursolic acid suppressed octanoylated ghrelin levels in AGS-GHRL8 cells without decreasing transcript expression of GOAT or furin, a protease required for ghrelin maturation. β-amyrin had no effect on octanoylated ghrelin level, which was only slightly inhibited by uvaol; the fact that both these triterpenes lack a carboxyl group indicates that this group is important for suppressing octanoylated ghrelin production. These results suggest that triterpenes may have the potential as obesity-preventing agents with suppressive effect on octanoylated ghrelin production.

Qiu H, Tang X, Ma J, et al.
Notch1 Autoactivation via Transcriptional Regulation of Furin, Which Sustains Notch1 Signaling by Processing Notch1-Activating Proteases ADAM10 and Membrane Type 1 Matrix Metalloproteinase.
Mol Cell Biol. 2015; 35(21):3622-32 [PubMed] Free Access to Full Article Related Publications
Notch1 is an evolutionarily conserved transmembrane receptor involved in melanoma growth. Notch1 is first cleaved by furin in the Golgi apparatus to produce the biologically active heterodimer. Following ligand binding, Notch1 is cleaved at the cell membrane by proteases such as ADAM10 and -17 and membrane type 1 matrix metalloproteinase (MT1-MMP), the latter of which we recently identified as a novel protease involved in Notch1 processing. The final cleavage is γ-secretase dependent and releases the active Notch intracellular domain (NIC). We now demonstrate that Notch1 directly regulates furin expression. Aside from activating Notch1, furin cleaves and activates several proteases, including MT1-MMP, ADAM10, and ADAM17. By chromatin immunoprecipitation and a reporter assay, we demonstrate that Notch1 binds at position -1236 of the furin promoter and drives furin expression. The Notch1-dependent enhancement of furin expression increases the activities of MT1-MMP and ADAM10 but not that of ADAM17, as demonstrated by short hairpin RNA (shRNA) knockdown of furin, and promotes the cleavage of Notch1 itself. These data highlight a novel positive-feedback loop whereby Notch1-dependent furin expression can induce Notch1 signaling by increasing Notch1 processing and by potentiating the activity of the proteases responsible for Notch1 activation. This leads to Notch1 signal amplification, which can promote melanoma tumor growth and progression, as demonstrated by the inhibition of cell migration and invasion upon furin inhibition downstream of Notch1. Disruption of such feedback signaling might represent an avenue for the treatment of melanoma.

Declercq J, Jacobs B, Biesmans B, et al.
Single Nucleotide Polymorphism (rs4932178) in the P1 Promoter of FURIN Is Not Prognostic to Colon Cancer.
Biomed Res Int. 2015; 2015:321276 [PubMed] Free Access to Full Article Related Publications
High expression of the proprotein processing enzyme FURIN has been associated with tumor progression and metastasis. A SNP (rs4932178) in the promoter of FURIN has been reported to affect expression in liver, with the T allele resulting in higher expression than the C allele. In this study we have investigated the association of this SNP with prognostic and biological subgroups of colorectal cancer (CRC). In a panel of 1382 patients with CRC, this SNP had no impact on overall survival or on postoperative risk of relapse. This SNP also could not be linked with FURIN expression levels in CRC samples from the patients. Furthermore, we demonstrate in luciferase reporter experiments in the colon cancer cell lines Caco-2 and SW480 and in the hepatocellular carcinoma cell line Huh 7 that expression is not affected by the SNP. Since, FURIN inhibition in human colon cancer cell lines has previously been shown to repress tumor metastases, association between FURIN gene expression levels and postoperative relapse-free survival was also investigated. However, no association could be found. Altogether, we could not confirm an effect of the SNP on FURIN expression in vitro and no correlations could be found in vivo with FURIN expression or outcome.

Rodríguez-García A, Svensson E, Gil-Hoyos R, et al.
Insertion of exogenous epitopes in the E3-19K of oncolytic adenoviruses to enhance TAP-independent presentation and immunogenicity.
Gene Ther. 2015; 22(7):596-601 [PubMed] Related Publications
Oncolytic adenoviruses can promote immune responses against tumors by expressing and/or displaying tumor-associated antigens. However, the strong immunodominance of viral antigens mask responses against tumor epitopes. In addition, defects in major histocompatibility complex class I antigen presentation pathway such as the downregulation of the transporter-associated with antigen processing (TAP) are frequently associated with immune evasion of tumor cells. To promote the immunogenicity of exogenous epitopes in the context of an oncolytic adenovirus, we have taken advantage of the ER localization of the viral protein E3-19K. We have inserted tumor-associated epitopes after the N-terminal signal sequence for membrane insertion of this protein and flanked them with linkers cleavable by the protease furin to facilitate their TAP-independent presentation. This strategy allowed an enhanced presentation of the exogenous epitopes in TAP-deficient tumor cells in vitro and the generation of higher specific immune responses in vivo that were able to significantly control tumor growth.

Timoshenko OS, Gureeva TA, Kugaevskaia EV, Solov'eva NI
[Membrane type 1 matrix metalloproteinase (MT1-MMP) and the regulators of its activity as invasive factors in squamous cell cervical carcinomas].
Biomed Khim. 2014 Nov-Dec; 60(6):683-8 [PubMed] Related Publications
Membrane type 1 matrix metalloproteinase (MT1MMP) is one of matrix metalloproteinases (MMP), which play а key role in tumor invasion and metastasis. The aim of this study was to elucidate the peculiarities of expression of MT1MMP and endogenous regulators of its activity: the activator - furin and the inhibitor - TIMP-2, as invasive factors of squamous cell cervical carcinomas (SCC). The study was carried out using 11 specimens of SCC and 11 specimens of morphologically normal tissue adjacent to the tumor. It was shown that the increase of MT1-MMP and furin expression and low of TIMP-2 expression makes the main contribution to the destructive (invasive) potential of SCC. Moreover, substantial expression of MT1-MMP was registered in the specimens of morphologically normal adjoining to tumor tissue. This expression was found to make an additional contribution to the destructive potential of the cervical tumor.

Yu R, Albarenque SM, Cool RH, et al.
DR4 specific TRAIL variants are more efficacious than wild-type TRAIL in pancreatic cancer.
Cancer Biol Ther. 2014; 15(12):1658-66 [PubMed] Free Access to Full Article Related Publications
Current treatment modalities for pancreatic carcinoma afford only modest survival benefits. TRAIL, as a potent and specific inducer of apoptosis in cancer cells, would be a promising new treatment option. However, since not all pancreatic cancer cells respond to TRAIL, further improvements and optimizations are still needed. One strategy to improve the effectiveness of TRAIL-based therapies is to specifically target one of the 2 cell death inducing TRAIL-receptors, TRAIL-R1 or TRAIL-R2 to overcome resistance. To this end, we designed constructs expressing soluble TRAIL (sTRAIL) variants that were rendered specific for either TRAIL-R1 or TRAIL-R2 by amino acid changes in the TRAIL ectodomain. When we expressed these constructs, including wild-type sTRAIL (sTRAIL(wt)), TRAIL-R1 (sTRAIL(DR4)) and TRAIL-R2 (sTRAIL(DR5)) specific variants, in 293 producer cells we found all to be readily expressed and secreted into the supernatant. These supernatants were subsequently transferred onto target cancer cells and apoptosis measured. We found that the TRAIL-R1 specific variant had higher apoptosis-inducing activity in human pancreatic carcinoma Colo357 cells as well as PancTu1 cells that were additionally sensitized by targeting of XIAP. Finally, we tested TRAIL-R1 specific recombinant TRAIL protein (rTRAIL(DR4)) on Colo357 xenografts in nude mice and found them to be more efficacious than rTRAIL(wt). Our results demonstrate the benefits of synthetic biological approaches and show that TRAIL-R1 specific variants can potentially enhance the therapeutic efficacy of TRAIL-based therapies in pancreatic cancer, suggesting that they can possibly become part of individualized and tumor specific combination treatments in the future.

Tao L, Pavlova SI, Gasparovich SR, et al.
Alcohol metabolism by oral streptococci and interaction with human papillomavirus leads to malignant transformation of oral keratinocytes.
Adv Exp Med Biol. 2015; 815:239-64 [PubMed] Related Publications
Poor oral hygiene, ethanol consumption, and human papillomavirus (HPV) are associated with oral and esophageal cancers. However, the mechanism is not fully known. This study examines alcohol metabolism in Streptococcus and its interaction with HPV-16 in the malignant transformation of oral keratinocytes. The acetaldehyde-producing strain Streptococcus gordonii V2016 was analyzed for adh genes and activities of alcohol and aldehyde dehydrogenases. Streptococcus attachment to immortalized HPV-16 infected human oral keratinocytes, HOK (HPV/HOK-16B), human oral buccal keratinocytes, and foreskin keratinocytes was studied. Acetaldehyde, malondialdehyde, DNA damage, and abnormal proliferation among keratinocytes were also quantified. We found that S. gordonii V2016 expressed three primary alcohol dehydrogenases, AdhA, AdhB, and AdhE, which all oxidize ethanol to acetaldehyde, but their preferred substrates were 1-propanol, 1-butanol, and ethanol, respectively. S. gordonii V2016 did not show a detectable aldehyde dehydrogenase. AdhE is the major alcohol dehydrogenase in S. gordonii. Acetaldehyde and malondialdehyde production from permissible Streptococcus species significantly increased the bacterial attachment to keratinocytes, which was associated with an enhanced expression of furin to facilitate HPV infection and several malignant phenotypes including acetaldehyde adduct formation, abnormal proliferation, and enhanced migration through integrin-coated basement membrane by HPV-infected oral keratinocytes. Therefore, expression of multiple alcohol dehydrogenases with no functional aldehyde dehydrogenase contributes to excessive production of acetaldehyde from ethanol by oral streptococci. Oral Streptococcus species and HPV may cooperate to transform oral keratinocytes after ethanol exposure. These results suggest a significant clinical interaction, but further validation is warranted.

Nemunaitis J, Barve M, Orr D, et al.
Summary of bi-shRNA/GM-CSF augmented autologous tumor cell immunotherapy (FANG™) in advanced cancer of the liver.
Oncology. 2014; 87(1):21-9 [PubMed] Related Publications
Therapies for advanced hepatocellular carcinoma (HCC) are limited. We carried out a phase I trial of a novel autologous whole-cell tumor cell immunotherapy (FANG™), which incorporates a dual granulocyte macrophage colony-stimulating factor (GM-CSF) expressive/bifunctional small hairpin RNA interference (bi-shRNAi) vector. The bi-shRNAi DNA targets furin, which is a proconvertase of transforming growth factors beta (TGFβ) 1 and 2. Safety, mechanism, immunoeffectiveness, and suggested benefit were previously shown [Senzer et al.: Mol Ther 2012;20:679-689; Senzer et al.: J Vaccines Vaccin 2013;4:209]. We now provide further follow-up of a subset of 8 HCC patients. FANG manufacturing was successful in 7 of 8 attempts (one failure due to insufficient cell yield). Median GM-CSF expression was 144 pg/10(6) cells, TGFβ1 knockdown was 100%, and TGFβ2 knockdown was 93% of the vector-transported cells. Five patients were vaccinated (1 or 2.5×10(7) cells/intradermal injection, 6-11 vaccinations). No FANG toxicity was observed. Three of these patients demonstrated evidence of an immune response to the autologous tumor cell sample. Long-term follow-up demonstrated survival of 319, 729, 784, 931+, and 1,043+ days of the FANG-treated patients. In conclusion, evidence supports further assessment of the FANG immunotherapy in HCC.

Kang S, Zhao Y, Hu K, et al.
miR-124 exhibits antiproliferative and antiaggressive effects on prostate cancer cells through PACE4 pathway.
Prostate. 2014; 74(11):1095-106 [PubMed] Related Publications
INTRODUCTION: PACE4 plays an important role in prostate cancer (PCa) proliferation and aggression, which might provide a useful target against prostate cancer. In this study, we had strived to find some key miRNAs to decrease malignancy and invasiveness of PCa through regulating PACE4 expression.
METHODS: Clinically pathological analysis of immunohistochemistry/in situ hybridization was carried out to detect the relationship between PACE4 expression/miRNAs and the malignancy of prostate mass. Prostate cell lines (DU145, C4-2, and BPH-1) were cultured for growth curve, immunocytochemistry analysis, colony formation, Matrigel invasion, and transcriptional/translational expression assay of PACE4-related signaling molecules for confirming the relationship. MiRNAs targeting PACE4 were predicted, validated and further-corroborated using bio-software, real-time PCR, luciferase reporter assay and transfection of miRNA mimics and inhibitor.
RESULTS: It was suggested that PACE4 might reflect the pathological malignancy of prostate lesion from pathology analysis. Moreover, DU145 cells, the highest PACE4-level and related TF expression indicated of the strongest malignancy and invasiveness. It was significantly found that miR-124 was presented with the biggest odd to target PACE4-3'UTR, the capability of decreasing PACE expression and slowing down cell growth and cell invasion.
CONCLUSIONS: It was clear that PACE4 level was closely associated with malignancy and invasiveness of PCa in vivo or in vitro MiR-124, played a crucial role inhibiting PACE4 transcription thus exhibiting obvious effects of antiproliferation and antiaggression of PCa.

Yang Y, Bai ZG, Yin J, et al.
Role of c-Src activity in the regulation of gastric cancer cell migration.
Oncol Rep. 2014; 32(1):45-9 [PubMed] Free Access to Full Article Related Publications
Gastric cancer is associated with increased migration and invasion. In the present study, we explored the role of c-Src in gastric cancer cell migration and invasion. BGC-823 gastric cancer cells were used to investigate migration following treatment of these cells with the c-Src inhibitors, PP2 and SU6656. Migration and invasion were analyzed by wound healing and Transwell assays. Western blot analysis was used to detect the expression of MT1-MMP and VEGF-C, while the activity of MMP2 and MMP9 was monitored with gelatin zymography assay. Immunoprecipitation was used to detect interactions among furin, pro-MT1-MMP and pro-VEGF-C. MT1-MMP and VEGF-C expression levels were inhibited by PP2 and SU6656 treatment, in accordance with decreased c-Src activity. Similarly, the zymography assay demonstrated that the activity of MMP2 and MMP9 was decreased following PP2 or SU6656 treatment. Blockade of c-Src also inhibited the invasive and migratory capacity of BGC-823 cells. Notably, c-Src interacted with furin in vivo, while interactions between furin and its substrates, pro-MT1-MMP and pro-VEGF-C, were decreased by c-Src inhibitors. In conclusion, the interaction among furin and pro-MT1-MMP or pro-VEGF-C or other tumor-associated precursor enzymes can be regulated by c-Src activity, thus reducing or changing the expression of these enzymes in order to reduce the development of gastric cancer, invasion and metastasis.

Vargas A, Zhou S, Éthier-Chiasson M, et al.
Syncytin proteins incorporated in placenta exosomes are important for cell uptake and show variation in abundance in serum exosomes from patients with preeclampsia.
FASEB J. 2014; 28(8):3703-19 [PubMed] Related Publications
Exosomes are extracellular vesicles that mediate intercellular communication and are involved in several biological processes. The objective of our study was to determine whether endogenous retrovirus group WE, member l (ERVWE1)/syncytin-1 and endogenous retrovirus group FRD, member 1 (ERVFRDE1)/syncytin-2, encoded by human endogenous retrovirus (HERV) envelope (env) genes, are present at the surface of exosomes produced by placenta-derived villous cytotrophoblasts and whether they play a role in cellular uptake of exosomes. In addition, we sought to determine whether these proteins are present in various abundances in serum-derived exosomes from normal pregnant women vs. women with preeclampsia (PE). Isolated exosomes were analyzed for their content by Western blot, a bead-associated flow cytometry approach, and a syncytin-2 ELISA. Binding and uptake were tested through confocal and electron microscopy using the BeWo choriocarcinoma cell line. Quality control of exosome preparations consisted of detection of exosomal and nonexosomal markers. Exosome-cell interactions were compared between cells incubated in the presence of control exosomes, syncytin-1 or syncytin-2-deprived exosomes, or exosomes solely bearing the uncleaved forms of these HERV env proteins. From our data, we conclude that villous cytotrophoblast exosomes are positive for both env proteins and are rapidly taken up by BeWo cells in a syncytin-1- and syncytin-2-dependent manner and that syncytin-2 is reduced in serum-derived exosomes from women with PE when compared to exosomes from normal pregnant women.

Fu J, Zhang J, Gong Y, et al.
Regulation of HIF-1 alpha by the proprotein convertases furin and PC7 in human squamous carcinoma cells.
Mol Carcinog. 2015; 54(9):698-706 [PubMed] Free Access to Full Article Related Publications
Proprotein convertases (PC), a family of serine proteases, process cancer-related substrates such as growth factors, growth factor receptors, cell adhesion molecules, metalloproteinases, etc. HIF-1α is a major transcription factor involved in tumorigenesis by sensing intratumoral hypoxia. Furin (PCSK3) is one of the numerous target genes regulated by HIF-1α transactivation and its distribution into endosomal compartments and onto the cell surface can be triggered by hypoxia via HIF-1α. siRNAs to knockdown PCs were transfected into cells alone or in combination with different drug treatments. Protein and RNA expression levels were analyzed by Western blotting or RT-PCR, respectively. PC7 (PCSK7) and furin siRNAs upregulated HIF-1α protein under normoxic condition to a level similar to that obtained by cobalt chloride treatment, eventually leading to activation of VEGF-A synthesis in two human head and neck squamous cell carcinoma cell lines. The unchanged levels of HIF-1α mRNA expression under siRNA treatment and the additive HIF-1α induction of PC siRNAs and either cobalt chloride or the 26S ribosome inhibitor, MG-132, suggested a post-transcriptional PC-mediated regulation. Furthermore, cycloheximide chase showed that PC7/furin siRNA regulation occurred at the level of HIF-1α translation. A specific IGF-1R signaling inhibitor was able to attenuate the PC siRNA induction of HIF-1α, suggesting the involvement of the IGF-1R pathway. Thus, the data show that PCs regulate HIF-1α. Furin and PC7 siRNAs induced HIF-1α protein by increasing its translation, resulting in upregulation of VEGF-A. This finding may provide insight into intricate PC functions that seem to be independent from their substrate-processing activity.

Liu XF, Xiang L, FitzGerald DJ, Pastan I
Antitumor effects of immunotoxins are enhanced by lowering HCK or treatment with SRC kinase inhibitors.
Mol Cancer Ther. 2014; 13(1):82-9 [PubMed] Free Access to Full Article Related Publications
Recombinant immunotoxins (RIT) are agents being developed for cancer treatment. They are composed of an Fv that binds to a cancer cell, fused to a 38-kDa fragment of Pseudomonas exotoxin A. SS1P is a RIT that targets mesothelin, a protein expressed on mesothelioma as well as pancreatic, ovarian, lung, and other cancers. Because the protein tyrosine kinase family regulates a variety of cellular processes and pathways, we hypothesized that tyrosine kinases might regulate susceptibility to immunotoxin killing. To investigate their role, we used siRNAs to lower the level of expression of the 88 known tyrosine kinases. We identified five tyrosine kinases, INSR, HCK, SRC, PDGFRβ, and BMX that enhance the activity of SS1P when their level of expression is lowered by siRNAs. We further investigated the Src family member HCK in this study. Knocking down of SRC slightly increased SS1P killing in A431/H9 cells, but knocking down HCK substantially enhanced killing by SS1P. We investigated the mechanism of enhancement and found that HCK knockdown enhanced SS1P cleavage by furin and lowered levels of Mcl-1 and raised Bax. We then found that Src inhibitors mimic the stimulatory effect of HCK knockdown; both SU6656 and SKI-606 (bosutinib) enhanced immunotoxin killing of mesothelin-expressing cells by SS1P and CD22-expressing cells by HA22 (moxetumomab pasudotox). SU6656 also enhanced the antitumor effects of SS1P and HA22 in mouse xenograft tumor models. Our data suggest that the combination of immunotoxin with tyrosine kinase inhibitors may be an effective way to treat some cancers.

Seim I, Jeffery PL, de Amorim L, et al.
Ghrelin O-acyltransferase (GOAT) is expressed in prostate cancer tissues and cell lines and expression is differentially regulated in vitro by ghrelin.
Reprod Biol Endocrinol. 2013; 11:70 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Ghrelin is a 28 amino acid peptide hormone that is expressed in the stomach and a range of peripheral tissues, where it frequently acts as an autocrine/paracrine growth factor. Ghrelin is modified by a unique acylation required for it to activate its cognate receptor, the growth hormone secretagogue receptor (GHSR), which mediates many of the actions of ghrelin. Recently, the enzyme responsible for adding the fatty acid residue (octanoyl/acyl group) to the third amino acid of ghrelin, GOAT (ghrelin O-acyltransferase), was identified.
METHODS: We used cell culture, quantitative real-time reverse transcription (RT)-PCR and immunohistochemistry to demonstrate the expression of GOAT in prostate cancer cell lines and tissues from patients. Real-time RT-PCR was used to demonstrate the expression of prohormone convertase (PC)1/3, PC2 and furin in prostate cancer cell lines. Prostate-derived cell lines were treated with ghrelin and desacyl ghrelin and the effect on GOAT expression was measured using quantitative RT-PCR.
RESULTS: We have demonstrated that GOAT mRNA and protein are expressed in the normal prostate and human prostate cancer tissue samples. The RWPE-1 and RWPE-2 normal prostate-derived cell lines and the LNCaP, DU145, and PC3 prostate cancer cell lines express GOAT and at least one other enzyme that is necessary to produce mature, acylated ghrelin from proghrelin (PC1/3, PC2 or furin). Finally, ghrelin, but not desacyl ghrelin (unacylated ghrelin), can directly regulate the expression of GOAT in the RWPE-1 normal prostate derived cell line and the PC3 prostate cancer cell line. Ghrelin treatment (100nM) for 6 hours significantly decreased GOAT mRNA expression two-fold (P < 0.05) in the PC3 prostate cancer cell line, however, ghrelin did not regulate GOAT expression in the DU145 and LNCaP prostate cancer cell lines.
CONCLUSIONS: This study demonstrates that GOAT is expressed in prostate cancer specimens and cell lines. Ghrelin regulates GOAT expression, however, this is likely to be cell-type specific. The expression of GOAT in prostate cancer supports the hypothesis that the ghrelin axis has autocrine/paracrine roles. We propose that the RWPE-1 prostate cell line and the PC3 prostate cancer cell line may be useful for investigating GOAT regulation and function.

Zhu J, Van de Ven W, Vermorken A
Polyphenols with indirect proprotein convertase inhibitory activity.
Int J Oncol. 2013; 43(3):947-55 [PubMed] Related Publications
Polyphenols, a class of natural products, have been shown to exhibit cancer protective properties. Proprotein convertases form a family of mammalian subtilisin-like serine endoproteases. Increased expression of these enzymes has been associated with numerous pathologies including cancer. It has been suggested that the cancer protective effect of polyphenols might be related to their proprotein convertase inhibitory effects. Furin, the most studied proprotein convertase, was shown to be inhibited by polyphenols in an in vitro fluorescence peptide-based assay. Protein substrates or the presence of protein prevented this inhibition by prototype members of various classes of polyphenolic compounds. Inhibition appeared to be related to the reactivity of polyphenol auto-oxidation products to proteins. While direct inhibition by polyphenols of furin has, therefore, not been observed in cells, the existence of indirect mechanisms cannot be excluded. In the present investigation, 26 polyphenols and 5 control compounds were screened for indirect inhibition of furin in a cellular environment. Five polyphenols showed moderate inhibitory activity and three of these: octyl gallate, dodecyl gallate and nordihydroguariaretic acid were further studied. The processing in cells of several genuine furin substrates, including pro-IGF-1R, appeared to be inhibited by these polyphenols. The inhibition was not specific for furin but also affected other proprotein convertases. The three polyphenols inhibited the maturation of the furin zymogen, thereby limiting the formation of the active enzyme. The three polyphenols inhibited focus formation of HepG2 liver carcinoma cells suggesting reversal of the malignant phenotype. Anchorage-independent growth of these cells, a hallmark feature of tumor cells, was also inhibited. Since, dependent of the molecular subclass of hepatocellular carcinoma, overexpression of furin can have either favourable or detrimental effects, it seems advisable to take indirect proprotein convertase inhibitory activity into account when polyphenols are considered for therapy of hepatocellular carcinoma.

Su Y, Yu L, Liu N, et al.
PSMA specific single chain antibody-mediated targeted knockdown of Notch1 inhibits human prostate cancer cell proliferation and tumor growth.
Cancer Lett. 2013; 338(2):282-91 [PubMed] Related Publications
The down-regulation of Notch1 by small interfering RNA (siRNA) can significantly inhibit human prostate cancer cell growth. The delivery of siRNA into specific cells is a key requirement for its clinical application. Recent reports have indicated that antibody-mediated siRNA delivery is an effective approach for targeted knockdown of specific genes in appropriate cells. Prostate-specific membrane antigen (PSMA) is regarded as an ideal target for the delivery of therapeutic agents to prostate cancer cells. The purpose of the present study was to evaluate whether siRNA can be efficiently delivered into PSMA-positive prostate cancer cells using two fusion proteins, s-tP and sFH-tP. These fusion proteins are composed of an anti-PSMA single chain antibody (scFv, abbreviated as an "s") and a truncated protamine (tP); and in sFH-tP a furin cleavage site and an HA2 fragment sequence (FH) were inserted between the scFv and tP domains. Our results showed that siRNA can be specifically delivered into PSMA-positive LNCaP cells by these two fusion proteins, with the sFH-tP fusion protein being more effective. Efficient knockdown of Notch1 by siNotch1 delivered by either fusion protein was observed in PSMA-positive LNCaP cells and in LNCaP xenografted nude mice. Further experiments confirmed that the fusion protein-delivered siNotch1 could efficiently inhibit PSMA-positive LNCaP cell proliferation and promote apoptosis both in vitro and in vivo. Our data describe a promising strategy for the targeted delivery of siRNA to PSMA-positive prostate cancer cells using anti-PSMA scFv fusion proteins.

Fu J, Bassi DE, Zhang J, et al.
Enhanced UV-induced skin carcinogenesis in transgenic mice overexpressing proprotein convertases.
Neoplasia. 2013; 15(2):169-79 [PubMed] Free Access to Full Article Related Publications
The proprotein convertases (PCs) furin and PACE4 process numerous substrates involved in tumor growth, invasion, and metastasis. We have previously shown that PCs increase the susceptibility to chemical skin carcinogenesis. Because of the human relevancy of UV radiation in the etiopathogenesis of human skin cancer, we investigated whether or not transgenic mice overexpressing either furin alone or both furin and PACE4 show increased susceptibility to UV carcinogenesis. After backcrossing our previously described furin and PACE4 transgenic lines, targeted to the epidermis, into a SKH-1 background, we exposed both single and double transgenic mice to UV radiation for 34 weeks. The results showed an increase in squamous cell carcinoma (SCC) multiplicity of approximately 70% in the single furin transgenic mouse line SF47 (P < .002) and a 30% increase in the other single transgenic line SF49 when compared to wild-type (WT) SKH-1 mice. Interestingly, there was also an increase in the percentage of high histologic grade SCCs in the transgenic lines compared to the WT mice, i.e., WT = 9%, SF47 = 15%, and SF49 = 26% (P < .02). Targeting both furin and PACE4 to the epidermis in double transgenic mice did not have an additive effect on tumor incidence/multiplicity but did enhance the tumor histopathologic grade, i.e., a significant increase in higher grade SCCs was seen in the bigenic mouse line SPF47 (P < .02). Thus, we observed an increased susceptibility to UV in single furin transgenic mice that was not substantially enhanced in the double furin/PACE4 transgenic mice.

Demidyuk IV, Shubin AV, Gasanov EV, et al.
Alterations in gene expression of proprotein convertases in human lung cancer have a limited number of scenarios.
PLoS One. 2013; 8(2):e55752 [PubMed] Free Access to Full Article Related Publications
Proprotein convertases (PCs) is a protein family which includes nine highly specific subtilisin-like serine endopeptidases in mammals. The system of PCs is involved in carcinogenesis and levels of PC mRNAs alter in cancer, which suggests expression status of PCs as a possible marker for cancer typing and prognosis. The goal of this work was to assess the information value of expression profiling of PC genes. Quantitative polymerase chain reaction was used for the first time to analyze mRNA levels of all PC genes as well as matrix metalloproteinase genes MMP2 and MMP14, which are substrates of PCs, in 30 matched pairs of samples of human lung cancer tumor and adjacent tissues without pathology. Significant changes in the expression of PCs have been revealed in tumor tissues: increased FURIN mRNA level (p<0.00005) and decreased mRNA levels of PCSK2 (p<0.007), PCSK5 (p<0.0002), PCSK7 (p<0.002), PCSK9 (p<0.00008), and MBTPS1 (p<0.00004) as well as a tendency to increase in the level of PCSK1 mRNA. Four distinct groups of samples have been identified by cluster analysis of the expression patterns of PC genes in tumor vs. normal tissue. Three of these groups covering 80% of samples feature a strong elevation in the expression of a single gene in cancer: FURIN, PCSK1, or PCSK6. Thus, the changes in the expression of PC genes have a limited number of scenarios, which may reflect different pathways of tumor development and cryptic features of tumors. This finding allows to consider the mRNAs of PC genes as potentially important tumor markers.

Couture F, D'Anjou F, Desjardins R, et al.
Role of proprotein convertases in prostate cancer progression.
Neoplasia. 2012; 14(11):1032-42 [PubMed] Free Access to Full Article Related Publications
Better understanding of the distinct and redundant functions of the proprotein convertase (PC) enzyme family within pathophysiological states has a great importance for potential therapeutic strategies. In this study, we investigated the functional redundancy of PCs in prostate cancer in the commonly used androgen-sensitive LNCaP and the androgen-independent DU145 human cell lines. Using a lentiviral-based shRNA delivery system, we examined in vitro and in vivo cell proliferation characteristics of knockdown cell lines for the endogenous PCs furin, PACE4, and PC7 in both cell lines. Of the three PCs, only PACE4 was essential to maintain a high-proliferative status, as determined in vitro using XTT proliferation assays and in vivo using tumor xenografts in nude mice. Furin knockdowns in both cell lines had no effects on cell proliferation or tumor xenograft growth. Paradoxically, PC7 knockdowns reduced in vitro cellular proliferation but had no effect in vivo. Because PCs act within secretion pathways, we showed that conditioned media derived from PACE4 knockdown cells had very poor cell growth-stimulating effects in vitro. Immunohistochemistry of PACE4 knockdown tumors revealed reduced Ki67 and higher p27(KIP) levels (proliferation and cell cycle arrest markers, respectively). Interestingly, we determined that the epidermal growth factor receptor signaling pathway was activated in PC7 knockdown tumors only, providing some explanations of the paradoxical effects of PC7 silencing in prostate cancer cell lines. We conclude that PACE4 has a distinct role in maintaining proliferation and tumor progression in prostate cancer and this positions PACE4 as a relevant therapeutic target for this disease.

Wottawa M, Leisering P, Ahlen Mv, et al.
Knockdown of prolyl-4-hydroxylase domain 2 inhibits tumor growth of human breast cancer MDA-MB-231 cells by affecting TGF-β1 processing.
Int J Cancer. 2013; 132(12):2787-98 [PubMed] Related Publications
The prolyl-4-hydroxylase domain 1-3 (PHD1-3) enzymes are regulating the protein stability of the α-subunit of the hypoxia-inducible factor-1 (HIF-1), which mediates oxygen-dependent gene expression. PHD2 is the main isoform regulating HIF-1α hydroxylation and thus stability in normoxia. In human cancers, HIF-1α is overexpressed as a result of intratumoral hypoxia which in turn promotes tumor progression. The role of PHD2 for tumor progression is in contrast far from being thoroughly understood. Therefore, we established PHD2 knockdown clones of MDA-MB-231 breast cancer cells and analyzed their tumor-forming potential in a SCID mouse model. Tumor progression was significantly impaired in the PHD2 knockdown MDA-MB-231 cells, which could be partially rescued by re-establishing PHD2 expression. In a RNA profile screen, we identified the secreted phosphoprotein 1 (SPP1) as one target, which is differentially regulated as a consequence of the PHD2 knockdown. Knockdown of PHD2 drastically reduced the SPP1 expression in MDA-MB-231 cells. A correlation of SPP1 and PHD2 expression was additionally verified in 294 invasive breast cancer biopsies. In subsequent analyses, we identified that PHD2 alters the processing of transforming growth factor (TGF)-β1, which is highly involved in SPP1 expression. The altered processing capacity was associated with a dislocation of the pro-protein convertase furin. Thus, our data demonstrate that in MDA-MB-231 cells PHD2 might affect tumor-relevant TGF-β1 target gene expression by altering the TGF-β1 processing capacity.

Kang TH, Ma B, Wang C, et al.
Targeted coating with antigenic peptide renders tumor cells susceptible to CD8(+) T cell-mediated killing.
Mol Ther. 2013; 21(3):542-53 [PubMed] Free Access to Full Article Related Publications
The potency of immunotherapies targeting endogenous tumor antigens is hindered by immune tolerance. We created a therapeutic agent comprised of a tumor-homing module fused to a functional domain capable of selectively rendering tumor cells sensitive to foreign antigen-specific CD8(+) T cell-mediated immune attack, and thereby, circumventing concerns for immune tolerance. The tumor-homing module is comprised of a single-chain variable fragment (scFv) that specifically binds to mesothelin (Meso), which is commonly overexpressed in human cancers, including ovarian tumors. The functional domain is comprised of the Fc portion of IgG2a protein and foreign immunogenic CD8(+) T cell epitope flanked by furin cleavage sites (R), which can be recognized and cleaved by furin that is highly expressed in the tumor microenvironment. We show that our therapeutic protein specifically loaded antigenic epitope onto the surface of mesothelin-expressing tumor cells, rendering tumors susceptible to antigen-specific cytotoxic CD8(+) T lymphocytes (CTL)-mediated killing in vitro and in vivo. Our findings have important implications for bypassing immune tolerance to enhance cancer immunotherapy.

Katoh M
Function and cancer genomics of FAT family genes (review).
Int J Oncol. 2012; 41(6):1913-8 [PubMed] Free Access to Full Article Related Publications
FAT1, FAT2, FAT3 and FAT4 are human homologs of Drosophila Fat, which is involved in tumor suppression and planar cell polarity (PCP). FAT1 and FAT4 undergo the first proteolytic cleavage by Furin and are predicted to undergo the second cleavage by γ‑secretase to release intracellular domain (ICD). Ena/VAPS‑binding to FAT1 induces actin polymerization at lamellipodia and filopodia to promote cell migration, while Scribble‑binding to FAT1 induces phosphorylation and functional inhibition of YAP1 to suppress cell growth. FAT1 is repressed in oral cancer owing to homozygous deletion or epigenetic silencing and is preferentially downregulated in invasive breast cancer. On the other hand, FAT1 is upregulated in leukemia and prognosis of preB‑ALL patients with FAT1 upregulation is poor. FAT4 directly interacts with MPDZ/MUPP1 to recruit membrane‑associated guanylate kinase MPP5/PALS1. FAT4 is involved in the maintenance of PCP and inhibition of cell proliferation. FAT4 mRNA is repressed in breast cancer and lung cancer due to promoter hypermethylation. FAT4 gene is recurrently mutated in several types of human cancers, such as melanoma, pancreatic cancer, gastric cancer and hepatocellular carcinoma. FAT1 and FAT4 suppress tumor growth via activation of Hippo signaling, whereas FAT1 promotes tumor migration via induction of actin polymerization. FAT1 is tumor suppressive or oncogenic in a context‑dependent manner, while FAT4 is tumor suppressive. Copy number aberration, translocation and point mutation of FAT1, FAT2, FAT3, FAT4, FRMD1, FRMD6, NF2, WWC1, WWC2, SAV1, STK3, STK4, MOB1A, MOB1B, LATS1, LATS2, YAP1 and WWTR1/TAZ genes should be comprehensively investigated in various types of human cancers to elucidate the mutation landscape of the FAT‑Hippo signaling cascades. Because YAP1 and WWTR1 are located at the crossroads of adhesion, GPCR, RTK and stem‑cell signaling network, cancer genomics of the FAT signaling cascades could be applied for diagnostics, prognostics and therapeutics in the era of personalized medicine.

Brant KA, Leikauf GD
Dysregulation of FURIN by prostaglandin-endoperoxide synthase 2 in lung epithelial NCI-H292 cells.
Mol Carcinog. 2014; 53(3):192-200 [PubMed] Related Publications
Because proprotein convertases (PCSKs) activate growth factors and matrix metalloproteinase, these enzymes have been implicated in non-small cell lung cancer tumor progression and aggressiveness. Previous studies indicate that one PCSK member, FURIN is overexpressed in NSCLC, but little is known regarding the mechanisms driving PCSKs expression during malignant change. We sought to determine whether prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase) (PTGS2) (aka COX2), whose expression is also frequently increased in NSCLC, differentially regulates PCSK expression and activity between normal (NHBE) and NSCLC epithelial cells (NCI-H292, NCI-H441, A549). NSCLC cells exhibit significantly greater cell-associated and secreted PCSK activity as compared with NHBE. The heightened activity is consistent with increased FURIN, PCSK4, and PCSK6 protein in the NCSLC cells. Inhibition of PTGS2 activity using NS-398 and siRNA decreased FURIN mRNA, protein, activity along with cell proliferation in NCI-H292 cells but not NHBE cells. NSCLC also expressed elevated levels of the transcription factor E2F1. When NCI-H292 cells were transfected with E2F1 siRNA, both PTGS2 expression and PCSK activity were attenuated, arguing a pivotal role for E2F1 in the differential regulation of PCSKs by PTGS2. Our results highlight a novel role for PTGS2 in NSCLC and may provide a mechanism, whereby PTGS2 inhibitors suppress lung cancer cell growth.

Wu JF, Hsu HY, Ni YH, et al.
Suppression of furin by interferon-γ and the impact on hepatitis B virus antigen biosynthesis in human hepatocytes.
Am J Pathol. 2012; 181(1):19-25 [PubMed] Related Publications
The roles of furin and intrahepatic cytokines in chronic heptatitis B virus (HBV) infection remain largely unknown. Here, we examined the relations between furin, IL-10, IL-12β, interferon (IFN)-γ, programed death (PD)-1, programed death ligand (PD-L)1, and the suppression of hepatitis B e antigen (HBeAg) and surface antigen (HBsAg) biosynthesis. Liver biopsies were performed on 20 chronically HBV-infected (15 HBeAg-positive and 5 HBeAg-negative) patients to assess liver inflammation/fibrosis, and mRNA levels of furin, IL-10, IL-12β, IFN-γ, PD-1, and PD-L1 were assessed by quantitative real-time PCR. IFN-γ mRNA abundance was associated with lower furin mRNA levels and higher PD-1 and PD-L1 mRNA levels in liver tissue from HBeAg-positive patients. IL-10 and IL-12β mRNA levels positively correlated with IFN-γ expression levels (P < 0.05). PD-L1 and furin mRNA levels were further assessed in IFN-γ-stimulated hepatoma cell lines with (HepG2.2.15 cells) and without (HepG2 and Huh7 cells) HBV replication. IFN-γ enhanced PD-L1 expression in hepatoma cells. In HepG2.2.15 cells, IFN-γ further suppressed furin and HBeAg expression. Furin inhibition and knockdown in HepG2.2.15 cells also down-regulated HBeAg and HBsAg biosynthesis. These data suggest that IFN-γ modulates the inflammatory response to avoid excessive hepatocyte damage through the enhancement of PD-1/PD-L1 expression, whereas furin suppression may contribute to a reduction in HBeAg/HBsAg biosynthesis.

de Lau WB, Snel B, Clevers HC
The R-spondin protein family.
Genome Biol. 2012; 13(3):242 [PubMed] Free Access to Full Article Related Publications
The four vertebrate R-spondin proteins are secreted agonists of the canonical Wnt/β-catenin signaling pathway. These proteins are approximately 35 kDa, and are characterized by two amino-terminal furin-like repeats, which are necessary and sufficient for Wnt signal potentiation, and a thrombospondin domain situated more towards the carboxyl terminus that can bind matrix glycosaminoglycans and/or proteoglycans. Although R-spondins are unable to initiate Wnt signaling, they can potently enhance responses to low-dose Wnt proteins. In humans, rare disruptions of the gene encoding R-spondin1 cause a syndrome of XX sex reversal (phenotypic male), palmoplantar keratosis (a thickening of the palms and soles caused by excess keratin formation) and predisposition to squamous cell carcinoma of the skin. Mutations in the gene encoding R-spondin4 cause anonychia (absence or hypoplasia of nails on fingers and toes). Recently, leucine-rich repeat-containing G-protein-coupled receptor (Lgr)4, Lgr5 and Lgr6, three closely related orphans of the leucine-rich repeat family of G-protein-coupled receptors, have been identified as receptors for R-spondins. Lgr5 and Lgr6 are markers for adult stem cells. Because R-spondins are potent stimulators of adult stem cell proliferation in vivo and in vitro, these findings might guide the therapeutic use of R-spondins in regenerative medicine.

Cork SM, Kaur B, Devi NS, et al.
A proprotein convertase/MMP-14 proteolytic cascade releases a novel 40 kDa vasculostatin from tumor suppressor BAI1.
Oncogene. 2012; 31(50):5144-52 [PubMed] Free Access to Full Article Related Publications
Brain-specific angiogenesis inhibitor 1 (BAI1), an orphan G protein-coupled receptor-type seven transmembrane protein, was recently found mutated or silenced in multiple human cancers and can interfere with tumor growth when overexpressed. Yet, little is known about its regulation and the molecular mechanisms through which this novel tumor suppressor exerts its anti-cancer effects. Here, we demonstrate that the N terminus of BAI1 is cleaved extracellularly to generate a truncated receptor and a 40-kDa fragment (Vasculostatin-40) that inhibits angiogenesis. We demonstrate that this novel proteolytic processing event depends on a two-step cascade of protease activation: proprotein convertases, primarily furin, activate latent matrix metalloproteinase-14, which then directly cleaves BAI1 to release the bioactive fragment. These findings significantly augment our knowledge of BAI1 by showing a novel post-translational mechanism regulating BAI1 activity through cancer-associated proteases, have important implications for BAI1 function and regulation, and present novel opportunities for therapy of cancer and other vascular diseases.

Casazza A, Kigel B, Maione F, et al.
Tumour growth inhibition and anti-metastatic activity of a mutated furin-resistant Semaphorin 3E isoform.
EMBO Mol Med. 2012; 4(3):234-50 [PubMed] Free Access to Full Article Related Publications
Secreted Semaphorin 3E (Sema3E) promotes cancer cell invasiveness and metastatic spreading. The pro-metastatic activity of Sema3E is due to its proteolytic fragment p61, capable of transactivating the oncogenic tyrosine kinase ErbB2 that associates with the Sema3E receptor PlexinD1 in cancer cells. Here, we show that a mutated, uncleavable variant of Sema3E (Uncl-Sema3E) binds to PlexinD1 like p61-Sema3E, but does not promote the association of PlexinD1 with ErbB2 nor activates the ensuing signalling cascade leading to metastatic spreading. Furthermore, Uncl-Sema3E competes with endogenous p61-Sema3E produced by tumour cells, thereby hampering their metastatic ability. Uncl-Sema3E also acts independently as a potent anti-angiogenic factor. It activates a PlexinD1-mediated signalling cascade in endothelial cells that leads to the inhibition of adhesion to extracellular matrix, directional migration and cell survival. The putative therapeutic potential of Uncl-Sema3E was validated in multiple orthotopic or spontaneous tumour models in vivo, where either local or systemic delivery of Uncl-Sema3E-reduced angiogenesis, growth and metastasis, even in the case of tumours refractory to treatment with a soluble vascular endothelial growth factor trap. In summary, we conclude that Uncl-Sema3E is a novel inhibitor of tumour angiogenesis and growth that concomitantly hampers metastatic spreading.

Senzer N, Barve M, Kuhn J, et al.
Phase I trial of "bi-shRNAi(furin)/GMCSF DNA/autologous tumor cell" vaccine (FANG) in advanced cancer.
Mol Ther. 2012; 20(3):679-86 [PubMed] Free Access to Full Article Related Publications
We performed a phase I trial of FANG vaccine, an autologous tumor-based product incorporating a plasmid encoding granulocyte-macrophage colony-stimulating factor (GMCSF) and a novel bifunctional short hairpin RNAi (bi-shRNAi) targeting furin convertase, thereby downregulating endogenous immunosuppressive transforming growth factors (TGF) β1 and β2. Patients with advanced cancer received up to 12 monthly intradermal injections of FANG vaccine (1 × 10(7) or 2.5 × 10(7) cells/ml injection). GMCSF, TGFβ1, TGFβ2, and furin proteins were quantified by enzyme-linked immunosorbent assay (ELISA). Safety and response were monitored. Vaccine manufacturing was successful in 42 of 46 patients of whom 27 received ≥1 vaccine. There were no treatment-related serious adverse events. Most common grade 1, 2 adverse events included local induration (n = 14) and local erythema (n = 11) at injection site. Post-transfection mean product expression GMCSF increased from 7.3 to 1,108 pg/10(6) cells/ml. Mean TGFβ1 and β2 effective target knockdown was 93.5 and 92.5% from baseline, respectively. Positive enzyme-linked immunospot (ELISPOT) response at month 4 was demonstrated in 9 of 18 patients serially assessed and correlated with survival duration from time of treatment (P = 0.025). Neither dose-adverse event nor dose-response relationship was noted. In conclusion, FANG vaccine was safe and elicited an immune response correlating with prolonged survival. Phase II assessment is justified.

Li M, Wu Y, Qiu Y, et al.
2A peptide-based, lentivirus-mediated anti-death receptor 5 chimeric antibody expression prevents tumor growth in nude mice.
Mol Ther. 2012; 20(1):46-53 [PubMed] Free Access to Full Article Related Publications
Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF superfamily, induces tumor cell death via death receptors on target cells, without adverse effects on most normal cells. Its receptors are therefore an attractive target for antibody-mediated tumor therapy. Here, we report the creation of a lentivirus vector constructed by linking the heavy chain and the light chain of the antibody with a 2A/furin self-processing peptide in a single open reading frame that expresses a novel chimeric antibody (named as zaptuximab) with tumoricidal activity, which is consisted of the variable region of a mouse anti-human DR5 monoclonal antibody, AD5-10, and the constant region of human immunoglobulin G1. Lentivirus-expressed zaptuximab bound specifically to its antigen, DR5, and exhibited significant apoptosis-inducing activity in various tumor cell lines. The packaged recombinant virus lenti-HF2AL showed strong apoptosis-inducing activity in vitro. Meanwhile, inoculated subcutaneous human colon HCT116 tumor formation in nude mice were inhibited significantly. Moreover, there was a synergistic effect of mitomycin C (MMC) on the observed tumoricidal efficacy, prolonging the life span of nude mice with orthotopic human lung tumor cancers. These data suggest that lentivirus-mediated, 2A peptide-based anti-DR5 chimeric antibody expression may have clinical utility as an anticancer treatment and may represent a rational adjuvant therapy in combination with chemotherapy.

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