The amino‐terminal fragment of human urokinase directs a recombinant chimeric toxin to target cells: internalization is toxin mediated

Fabbrini, Maria Serena; Carpani, Daniela; Bello-Rivero, I; Soria, Marco R.

doi:10.1096/fasebj.11.13.9367352

Cited by 43 publications

(65 citation statements)

References 24 publications

(1 reference statement)

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“…11 and in anticancer therapy, to construct immunotoxins or ligand toxins [18][19][20][21] and SAP complementary DNA (cDNA) has been used for expressing targeted recombinant chimeras. 17,[22][23][24][25] When a SAP-based secretory chimera was expressed in Xenopus laevis oocytes, total inhibition of cellular protein synthesis was observed that could be restored only by supplementing neutralizing anti-SAP antibodies into the oocyte cytosol, 26 indicating that, although almost all of the chimera was secreted, the few molecules escaping from the secretory pathway were sufficient to inactivate protein synthesis in the host cells.…”

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confidence: 99%

Saporin as a novel suicide gene in anticancer gene therapy

et al. 2006

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We used a non-viral gene delivery approach to explore the potential of the plant saporin (SAP) gene as an alternative to the currently employed suicide genes in cancer therapy. Plasmids expressing cytosolic SAP were generated by placing the region encoding the mature plant ribosome-inactivating protein under the control of cytomegalovirus (CMV) or simian virus 40 (SV40) promoters. Their ability to inhibit protein synthesis was first tested in cultured tumor cells co-transfected with a luciferase reporter gene. In particular, SAP expression driven by CMV promoter (pCI-SAP) demonstrated that only 10 ng of plasmid per 1.6 Â 10 4 B16 cells drastically reduced luciferase activity to 18% of that in control cells. Direct intratumoral injection of pCI-SAP complexed with either lipofectamine or N-(2,3-dioleoyloxy-1-propyl) trimethylammonium methyl sulfate (DOTAP) in B16 melanoma-bearing mice resulted in a noteworthy attenuation of tumor growth. This antitumor effect was increased in mice that received repeated intratumoral injections. A SAP catalytic inactive mutant (SAP-KQ) failed to exert any antitumor effect demonstrating that this was specifically owing to the SAP N-glycosidase activity. Our overall data strongly suggest that the gene encoding SAP, owing to its rapid and effective action and its independence from the proliferative state of target cells might become a suitable candidate suicide gene for oncologic applications.

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confidence: 99%

Saporin as a novel suicide gene in anticancer gene therapy

et al. 2006

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“…However, these approaches would only be expected to slow the progression of tumors without having a direct cytotoxic action that could eradicate the malignant cells. Several studies have targeted protein toxins to uPAR, in several cases by fusion of toxin catalytic domains to ATF (73)(74)(75). However, the present study is the first attempt of which we are aware to exploit the substrate specific protease activity of the plasminogen activators to target cytotoxic bacterial toxin fusion proteins to tumor FIG.…”

Section: Discussionmentioning

confidence: 97%

Targeting of Tumor Cells by Cell Surface Urokinase Plasminogen Activator-dependent Anthrax Toxin

Liu

Bugge

Leppla

2001

Journal of Biological Chemistry

159

169

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Urokinase plasminogen activator receptor (uPAR) binds pro-urokinase plasminogen activator (pro-uPA) and thereby localizes it near plasminogen, causing the generation of active uPA and plasmin on the cell surface. uPAR and uPA are overexpressed in a variety of human tumors and tumor cell lines, and expression of uPAR and uPA is highly correlated to tumor invasion and metastasis. To exploit these characteristics in the design of tumor cell-selective cytotoxins, we constructed mutated anthrax toxin-protective antigen (PrAg) proteins in which the furin cleavage site is replaced by sequences cleaved specifically by uPA. These uPA-targeted PrAg proteins were activated selectively on the surface of uPAR-expressing tumor cells in the presence of pro-uPA and plasminogen. The activated PrAg proteins caused internalization of a recombinant cytotoxin, FP59, consisting of anthrax toxin lethal factor residues 1-254 fused to the ADP-ribosylation domain of Pseudomonas exotoxin A, thereby killing the uPAR-expressing tumor cells. The activation and cytotoxicity of these uPA-targeted PrAg proteins were strictly dependent on the integrity of the tumor cell surface-associated plasminogen activation system. We also constructed a mutated PrAg protein that selectively killed tissue plasminogen activator-expressing cells. These mutated PrAg proteins may be useful as new therapeutic agents for cancer treatment.

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“…This dual silencing approach achieved better tumor inhibition than silencing each oncogene alone. Unlike the cytotoxic chemotherapy agents that often share similar toxicities, limiting their use in combination, 41 synergistically inhibiting two key oncogenes with a plasmid-based RNAi strategy could achieve intended effects efficiently and specifically in vitro and in vivo. This result may offer potential opportunities for clinical cancer therapy.…”

Section: Discussionmentioning

confidence: 99%

Combined silencing of K-ras and Akt2 oncogenes achieves synergistic effects in inhibiting pancreatic cancer cell growth in vitro and in vivo

et al. 2008

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Cancer is a complex disease involving multiple oncogenes with diverse actions. Inhibiting only one oncogene is unlikely to eliminate the malignancy of cancer cells. The goal of this study was to investigate whether synergistic effects can be achieved by combined silencing of two oncogenes, K-ras and Akt2, which are key players in the Ras/MAPK and PI3K/Akt signaling pathways. The pancreatic cancer cell line, Panc-1, was selected for these studies as it has elevated expression of K-ras and Akt2. Compared with inhibiting each oncogene alone, simultaneously silencing the two oncogenes with RNA interference (RNAi) more effectively inhibited Panc-1 cell proliferation and colony formation, induced a significantly higher percentage of apoptosis and resulted in greater inhibition of c-myc expression in vitro. Furthermore, when delivered by polyethyleneimine into Panc-1 tumors in nude mice, RNAi simultaneously targeting K-ras and Akt2 inhibited tumor growth more efficiently than RNAi targeting the individual oncogenes. Therefore, RNAi simultaneously silencing the oncogenes K-ras and Akt2 may offer potential opportunities for pancreatic cancer gene therapy.

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The amino‐terminal fragment of human urokinase directs a recombinant chimeric toxin to target cells: internalization is toxin mediated

Cited by 43 publications

References 24 publications

Saporin as a novel suicide gene in anticancer gene therapy

Saporin as a novel suicide gene in anticancer gene therapy

Targeting of Tumor Cells by Cell Surface Urokinase Plasminogen Activator-dependent Anthrax Toxin

Combined silencing of K-ras and Akt2 oncogenes achieves synergistic effects in inhibiting pancreatic cancer cell growth in vitro and in vivo

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