Comparative Sensitivity of Microvascular Endothelial Cells, Fibroblasts and Tumor Cells after In Vitro Photodynamic Therapy with meso-Tetra-Hydroxyphenyl-Chlorin¶

2007 ◽  
Vol 80 (2) ◽  
pp. 236-241
Author(s):  
Martijn Triesscheijn ◽  
Marjan Ruevekamp ◽  
Maurice Aalders ◽  
Paul Baas ◽  
Fiona A. Stewart
2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 14144-14144
Author(s):  
C. Echart ◽  
M. Iacobelli ◽  
P. Richardson ◽  
C. Mitsiades ◽  
T. Ignoni ◽  
...  

14144 Background: Defibrotide (DF) is a mixture of polydeoxyribonucleotides with anti-thrombotic activity. Next to endothelium stabilization, recent data suggest anti-neoplastic properties of DF modulating interactions of tumor cells with their microenvironment. We investigated whether DF regulates expression and activity of heparanase, an enzyme critically involved in breaking down extracellular barriers and releasing growth factors linked to tumor invasion and angiogenesis. Methods: Heparanase expression was tested by RT-PCR and flow cytometry with multiple myeloma (MM) and microvascular endothelial cells. Heparanase activity was measured in cellular extracts with a heparan-degrading enzymatic assay. Serum degradation products of DF were identified by SEC-HPLC. The anti-angiogenic potential of DF was tested in vitro using a kit with human microvascular endothelial cells forming tubes across a layer of fibroblasts. In vivo, DF was tested in the dorsal skin-fold chamber assay in mice after inoculation of human gastric cancer cells. Proliferation was assessed by trypan blue exclusion. Results: We demonstrate a striking downregulation of expression and enzymatic activity of heparanase in endothelial as well as MM cells. In contrast, the degradation products of DF failed to exert any biological activity, suggesting that the intact mixture of deoxyoligonucleotides is responsible for the anti-tumor effect. We could also show that DF prevents (tumor) angiogenesis in vitro and in vivo. Western blots suggest that DF reduces phosphorylation-activation of p70S6 kinase, a key target in the mTOR pathway linked to angiogenesis. In addition, DF does not influence proliferation of vascular or tumor cells, rather acts via selective inhibition of tube formation of endothelial cells. Conclusion: In the present report we provide evidence for an anti-tumor activity of DF. DF inhibits (tumor) vessel formation and heparanase activity, and thus should be considered as an anti-cancer agent. [Table: see text]


1990 ◽  
Vol 111 (2) ◽  
pp. 773-781 ◽  
Author(s):  
I Cornil ◽  
R S Kerbel ◽  
J W Dennis

Cell surface carbohydrate structures acting as ligands for tissue specific mammalian lectins have been implicated in cell-cell interactions during embryogenesis, lymphocyte homing, and tumor cell metastasis. In this report, we provide evidence that beta 1-4 linked galactose (Gal) residues in N-linked oligosaccharides on the surface of blood born tumor cells serve as a ligand for binding to microvascular endothelial cells. D36W25, a class 1 glycosylation mutant of the MDAY-D2 lymphoreticular tumor cell line, lacks sialic acid and Gal in cellular glycans due to a defect in the Golgi UDP-Gal transporter. Using UDP-Gal and bovine galactosyltransferase in vitro, beta 1-4 Gal was restored to the surface of the cells and 70% of the galactosylated glycans persisted for 8 h in vitro at 37 degrees C. Compared to mock-treated D36W25 cells, galactosylated D36W25 cells showed an 80% increase in binding to microvascular endothelial cell monolayers in vitro. The enhanced binding of galactosylated D36W25 cells to endothelial cell was inhibited by the addition of lactosamine-conjugated albumin to the assay. Consistent with these observations, swainsonine and castinospermine, two inhibitors of N-linked processing that result in loss of lactosamine antennae inhibited the binding of wild-type MDAY-D2 cells to endothelial cells in vitro. Injection of radiolabeled tumor cells into the circulation of syngeneic mice, showed that galactosylation of D36W25 cells resulted in 2-3 more tumor cells retained in the lungs and livers. In addition, galactosylation of D36W25 cells increased by 30-fold the number of visible liver metastases on inspection 4 wk after tumor cell injection. These results suggest that beta 1-4Gal-binding lectins on microvascular endothelial cells can contribute to retention and secondary tumor formation of blood born tumor cells. With the increasing availability of purified glycosyltransferases, reconstruction of a variety of carbohydrate sequences on the surface of class 1 mutants provides a controlled means of studying carbohydrate-lectin interactions on viable cells.


1996 ◽  
Vol 36 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Nobuhiro Ichikawa ◽  
Kohji Naora ◽  
Hidenari Hirano ◽  
Michio Hashimoto ◽  
Sumio Masumura ◽  
...  

Author(s):  
Isabel Burghardt ◽  
Judith Johanna Schroeder ◽  
Tobias Weiss ◽  
Dorothee Gramatzki ◽  
Michael Weller

Abstract Purpose Members of the transforming growth factor (TGF)-β superfamily play a key role in the regulation of the malignant phenotype of glioblastoma by promoting invasiveness, angiogenesis, immunosuppression, and maintaining stem cell-like properties. Betaglycan, a TGF-β coreceptor also known as TGF-β receptor III (TβRIII), interacts with members of the TGF-β superfamily and acts as membrane-associated or shed molecule. Shed, soluble TβRIII (sTβRIII) is produced upon ectodomain cleavage of the membrane-bound form. Elucidating the role of TβRIII may improve our understanding of TGF-β pathway activity in glioblastoma Methods Protein levels of TβRIII were determined by immunohistochemical analyses and ex vivo single-cell gene expression profiling of glioblastoma tissue respectively. In vitro, TβRIII levels were assessed investigating long-term glioma cell lines (LTCs), cultured human brain-derived microvascular endothelial cells (hCMECs), glioblastoma-derived microvascular endothelial cells, and glioma-initiating cell lines (GICs). The impact of TβRIII on TGF-β signaling was investigated, and results were validated in a xenograft mouse glioma model Results Immunohistochemistry and ex vivo single-cell gene expression profiling of glioblastoma tissue showed that TβRIII was expressed in the tumor tissue, predominantly in the vascular compartment. We confirmed this pattern of TβRIII expression in vitro. Specifically, we detected sTβRIII in glioblastoma-derived microvascular endothelial cells. STβRIII facilitated TGF-β-induced Smad2 phosphorylation in vitro and overexpression of sTβRIII in a xenograft mouse glioma model led to increased levels of Smad2 phosphorylation, increased tumor volume, and decreased survival Conclusions These data shed light on the potential tumor-promoting role of extracellular shed TβRIII which may be released by glioblastoma endothelium with high sTβRIII levels.


1993 ◽  
Vol 264 (2) ◽  
pp. H639-H652 ◽  
Author(s):  
M. Nishida ◽  
W. W. Carley ◽  
M. E. Gerritsen ◽  
O. Ellingsen ◽  
R. A. Kelly ◽  
...  

Although reciprocal intercellular signaling may occur between endocardial or microvascular endothelium and cardiac myocytes, suitable in vitro models have not been well characterized. In this report, we describe the isolation and primary culture of cardiac microvascular endothelial cells (CMEC) from both adult rat and human ventricular tissue. Differential uptake of fluorescently labeled acetylated low-density lipoprotein (Ac-LDL) indicated that primary isolates of rat CMEC were quite homogeneous, unlike primary isolates of human ventricular tissue, which required cell sorting based on Ac-LDL uptake to create endothelial cell-enriched primary cultures. The endothelial phenotype of both primary isolates and postsort subcultured CMEC and their microvascular origin were determined by characteristic histochemical staining for a number of endothelial cell-specific markers, by the absence of cells with fibroblast or pericyte-specific cell surface antigens, and by rapid tube formation on purified basement membrane preparations. Importantly, [3H]-thymidine uptake was increased 2.3-fold in subconfluent rat microvascular endothelial cells 3 days after coculture with adult rat ventricular myocytes because of release of an endothelial cell mitogen(s) into the extracellular matrix, resulting in a 68% increase in cell number compared with CMEC in monoculture. Thus biologically relevant cell-to-cell interactions can be modeled with this in vitro system.


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