[Tumor cell-tumor endothelial cell adhesion mediated by alphavbeta3 and alphavbeta5 molecules].

OBJECTIVE: To investigate the role of adhesion molecules alphavbeta3 and alphavbeta5 and their ligands Del-1 and L1 in the tumor-endothelial cell adhesion in vitro. METHODS: The expression of alphavbeta3, alphavbeta5 and ICAM-1 in liver sinusoidal endothelial cells (LSEC) and liver cancer endothelial cells (T3A) cultured under normoxia or hypoxia were analyzed by RT-PCR and fluorescent activated cell sorter (FACS). The expression of Del-1 and L1 in six tumor cell lines under normoxia or hypoxia were analyzed by RT-PCR and Western blot, respectively. The adhesion of dye-labeled tumor cells and endothelial LSEC and T3A cells was measured by a fluorescence plate reader after their culture. RESULTS: The expression of alphavbeta3 and alphavbeta5 were higher in T3A cells than that in LSEC cells, and were upregulated under hypoxia, while the expression of ICAM-1 was lower in T3A cells than that in LSEC cells, and was upregulated under hypoxia only in LSEC. The expression of Del-1 and L1 molecules were obviously different in various tumor cell lines and were differentially regulated under hypoxia. The adhesion of tumor cells with Del-1 or L1 expression was higher in T3A cells than that in LSEC cells, and was significantly increased under hypoxia condition. Furthermore, the adhesion of tumor cells to T3A could be inhibited by antibodies against alphavbeta3 and alphavbeta5, or SiRNAs for beta3 and beta5. CONCLUSION: alphavbeta3 and alphavbeta5 and their ligands Del-1 and L1 may play an important role in tumor cell migration.

Phenotypic and functional differences between human liver cancer endothelial cells and liver sinusoidal endothelial cells.

BACKGROUND/AIMS: The phenotypic and functional characteristics of microvascular endothelial cells derived from human liver cancer (HLCEC) were analyzed in vitro and compared with those of human liver sinusoidal endothelial cells (LSEC). METHODS AND RESULTS: Flow-cytometric and real-time PCR analysis indicated that expressions of tumor necrosis factor receptor (TNFR) p75, alphavbeta3 and alphavbeta5 were increased, while those of TNFR p55 and intercellular-adhesion molecule 1 (ICAM-1) were decreased in HLCEC compared with LSEC. The functional analysis indicated that HLCEC exhibited higher angiogenic ability than LSEC, including proliferation capacity, ability to form capillary-like networks and release of matrix metalloproteinases. In response to tumor necrosis factor, LSEC exhibited a significant dose-dependent cytotoxicity, while HLCEC did not. Moreover, the coagulant and fibrinolytic capacity was increased in HLCEC. In addition, tumor cell adherence was significantly higher on HLCEC than on LSEC, while leukocyte adherence was lower on HLCEC than on LSEC. The cytoadherence of HLCEC was inhibited by antibodies against alphavbeta3 and alphavbeta5,and of LSEC by antibodies against ICAM-1. CONCLUSION: These results indicate that tumor-derived endothelial cells are phenotypically and functionally different from those derived from normal liver tissue. These differences are valuable for understanding tumor angiogenesis and metastasis.

The role of adhesion molecules, alpha v beta 3, alpha v beta 5 and their ligands in the tumor cell and endothelial cell adhesion.

Tumor metastasis is a complex process involving the interaction between tumor cells and endothelial cells in which some adhesion molecules play an important role. It was our aim to investigate the role of the adhesion molecules, alpha v beta 3 and alpha v beta 5 and their ligands, developmental endothelial locus-1 (Del-1) and L1, in tumor cell adhesion to endothelial cells in vitro. In this study, the expression and regulation of alpha v beta 3, alpha v beta 5 and intercellular adhesion molecule -1 on liver sinusoidal endothelial cells and liver cancer endothelial cells (T3A) were analyzed by real-time PCR and fluorescent-activated cell sorter. The expression and regulation of the integrin ligands, Del-1 and L1, in six tumor cell lines were analyzed by real-time PCR and western blot. We found the expressions of alpha v beta 3 and alpha v beta 5 were higher on T3A than that on liver sinusoidal endothelial cells, whereas expression of intercellular adhesion molecule-1 was lower on T3A than that on liver sinusoidal endothelial cells. After 24 h hypoxia, the expressions of alpha v beta 3 and alpha v beta 5 were upregulated on T3A and liver sinusoidal endothelial cells; the expression of intercellular adhesion molecule-1 was increased on liver sinusoidal endothelial cells, but remained unchanged on T3A. Del-1 and L1 expression levels were obviously diverse in various tumor cell lines and differentially modulated after 12 h hypoxia. The adhesion of tumor cells with Del-1 and L1 expression was higher in T3A than that in liver sinusoidal endothelial cells, and was significantly increased under hypoxic conditions. Interestingly, the tumor cell adherence could be inhibited by antibodies against alpha v beta 5 and alpha v beta 5, but not by an antibody against intercellular adhesion molecule-1. The adhesion of tumor cells without Del-1 and L1 expression was also higher on T3A than that on liver sinusoidal endothelial cells, but the adhesion could not be inhibited by antibodies against alpha v beta 5, alpha v beta 5 or intercellular adhesion molecule-1, suggesting that other receptors are involved. In conclusion, alpha v beta 5, alpha v beta 5 and their ligands Del-1 and L1 play an important role in the process of tumor cells moving from the original place.

[Characteristics of endothelial cells derived from human hepatic cavernous hemangioma in vitro].

OBJECTIVE: To investigate the characteristics of endothelial cells derived from human cavernous hemangioma in morphology, phenotypes and functions. METHODS: Endothelial cells were isolated from human hepatic cavernous hemangioma. The morphological, and phenotypical and functional features of these cells were analyzed by transmission electron microscopy, fluorescence-activated cell sorter, RT-PCR, zymography, and confocal microscopy. Human liver sinusoidal endothelial cells (LSEC) were used as control. RESULTS: As compared with the LSEC, abnormally expanded endoplasmic reticulums and similarly arranged cytoplasmic vacuoles were found in the endothelial cells derived from hepatic cavernous hemangioma (HCHEC) by transmission electron microscopy. Flow cytometry showed that expression of alphavbeta3 was significantly increased in the HCHEC. The mRNA of vascular endothelial cell growth factor and angiopoietin 1 were more abundant in HCHEC than that in LSEC. Functional analysis indicated that the HCHEC exhibited strong activated angiogenesis capacity and formed abnormal capillary-like structures. HCHEC produced more pro-matrix metalloproteinase 2 (MMP-2) and the activated MMP-2 form as compared with the LSEC. Confocal microscopy revealed that MMP-2 was concentrated in those cytoplasmic granules of the HCHEC and was consistent with the distribution of the expanded endoplasmic reticulums. CONCLUSION: The endothelial cells derived from human cavernous hemangioma differ from the normal endothelial cells in morphology, phenotypes and functions.

Morphologic, phenotypic and functional characteristics of endothelial cells derived from human hepatic cavernous hemangioma.

BACKGROUNDS/AIMS: The pathogenesis of cavernous hemangiomas is largely unknown, and it is speculated that abnormal vasculogenesis and angiogenesis may be involved. In this study, the characteristics of cavernous hemangioma endothelial cells (CHECs) derived from the human liver were analyzed in terms of morphology, phenotype and function and compared with human liver sinusoidal endothelial cells (LSECs). METHODS AND RESULTS: By transmission electron microscopy, abnormally expanded endoplasmic reticulum (ER) and similarly arranged cytoplasmic vacuoles were only found in CHECs. Phenotypic analysis showed that the expression of alphavbeta3 was significantly increased in CHECs. mRNA expression of vascular endothelial growth factor A, and angiopoietins 1 and 2 was significantly increased in CHECs compared to LSECs. The functional analysis indicated that CHECs released more vascular endothelial growth factor A, produced significantly more pro-matrix metalloproteinase 2 (pro-MMP2) and activated MMP2, and exhibited higher procoagulant and fibrinolytic activities compared with LSECs. Confocal microscopy revealed that MMP2 was concentrated in some cytoplasmic granules of CHECs and was consistent with the distribution of expanded ER. CHECs exhibited more activated angiogenesis capacity and formed abnormal capillary-like structures in vitro. CONCLUSION: These results suggested that endothelial cells (ECs) derived from human cavernous hemangiomas differ from normal ECs in morphology, phenotype and function.

[Induction of anti-tumor immunity by HSP gp96-peptide complexes].

AIM: To immunize the mice with gp96-peptide complexes extracted and purified from different kinds of malignant tumor cells and to observe anti-tumor immunity induced by the complexes. METHODS: HSP gp96-peptide complexes were extracted and purified from different kinds of malignant tumor cells. Mice were immunized subcutaneously with the complexes from different sources at different doses. Then the mice were challenged with 2 x 10(5) tumor cells on the seventh day after the last immunization. Tumor incidence, weight and histology were observed and compared with those of control group. At the meantime, cytotoxicity activity and nitric oxide production of mouse peritoneal macrophages were detected in vitro after being stimulated with gp96-peptide complexes. RESULTS: The SDS-PAGE and Western blot showed that gp96-peptide complexes were purified successfully. The anti-tumor immunity was correlated with the dose of the complex and the immunized mice could resist the challenge of homogeneous tumor cells. NO secreted from the peritoneal macrophages stimulated with the complex was significantly higher than that of control group and the tumoricidal activity of the macrophages in vitro was markedly promoted by the complex. CONCLUSION: Mice immunized with appropriate dose of gp96-peptide complexes from H22 tumor cells can resist the challenge of syngeneic tumor cells. NO secreted by macrophages stimulated with the complex might play a key role in the anti-tumor immunity.