TY - JOUR
T1 - The effect of a monoclonal antibody coupled to ricin a chain-derived peptides on endothelial cells in vitro
T2 - Insights into toxin-mediated vascular damage
AU - Baluna, Roxana
AU - Coleman, Elaine
AU - Jones, Chandria
AU - Ghetie, Victor
AU - Vitetta, Ellen S.
N1 - Funding Information:
1To whom reprint requests should be addressed. Fax: (214) 648-1204. E-mail: evitet@mednet.swmed.edu. 2Supported by NIH Grant CA-77701.
PY - 2000/8/1
Y1 - 2000/8/1
N2 - Immunotoxins (ITs) containing plant or bacterial toxins have a dose- limiting toxicity of vascular leak syndrome (VLS) in humans. The active A chain of ricin texan (RTA), ether toxins, ribosome-inactivating proteins, and the VLS-inducing cytokine IL-2 contain the conserved sequence motif (x)D(y) where x = L, I, G, or V and y = V, L, or S. RTA-derived LDV-containing peptides attached to a monoclonal antibody, RFB4, induce endothelial cell (EC) damage in vitro and vascular leak in two animal models in vivo. We have now investigated the mechanism(s) by which this occurs and have found that (1) the exposed D75 in the LDV sequence in RTA and the C-terminal flanking threonine play critical roles in the ability of RFB4-conjugated RTA peptide to bind to and damage ECs and (2) the LDV sequence in RTA induces early manifestations of apoptosis in HUVECs by activating caspase-3. These data suggest that RTA-mediated inhibition of protein synthesis (due to its active site) and apoptosis (due to LDV) may be mediated by different portions of the RTA molecule. These results suggest that ITs prepared with RTA mutants containing alterations in LDVT may kill tumor cells in vivo in the absence of EC-mediated VLS. (C) 2000 Academic Press.
AB - Immunotoxins (ITs) containing plant or bacterial toxins have a dose- limiting toxicity of vascular leak syndrome (VLS) in humans. The active A chain of ricin texan (RTA), ether toxins, ribosome-inactivating proteins, and the VLS-inducing cytokine IL-2 contain the conserved sequence motif (x)D(y) where x = L, I, G, or V and y = V, L, or S. RTA-derived LDV-containing peptides attached to a monoclonal antibody, RFB4, induce endothelial cell (EC) damage in vitro and vascular leak in two animal models in vivo. We have now investigated the mechanism(s) by which this occurs and have found that (1) the exposed D75 in the LDV sequence in RTA and the C-terminal flanking threonine play critical roles in the ability of RFB4-conjugated RTA peptide to bind to and damage ECs and (2) the LDV sequence in RTA induces early manifestations of apoptosis in HUVECs by activating caspase-3. These data suggest that RTA-mediated inhibition of protein synthesis (due to its active site) and apoptosis (due to LDV) may be mediated by different portions of the RTA molecule. These results suggest that ITs prepared with RTA mutants containing alterations in LDVT may kill tumor cells in vivo in the absence of EC-mediated VLS. (C) 2000 Academic Press.
KW - Endothelial cells
KW - Immunotoxins disintegrins
KW - Vascular leak syndrome
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U2 - 10.1006/excr.2000.4954
DO - 10.1006/excr.2000.4954
M3 - Article
C2 - 10896793
AN - SCOPUS:0034255636
SN - 0014-4827
VL - 258
SP - 417
EP - 424
JO - Experimental Cell Research
JF - Experimental Cell Research
IS - 2
ER -