Collagen is a survival factor against LPS-induced apoptosis in cultured sheep pulmonary artery endothelial cells

Abstract

Lipopolysaccharide (LPS) causes direct pulmonary endothelial injury that can precipitate cell death. We investigated the ability of LPS to produce apoptosis in sheep pulmonary artery endothelial cells (SPAEC) grown in monolayer on plastic or collagen. When SPAEC were grown on plastic, LPS (100 ng/ml) caused internucleosomal DNA fragmentation (IDF) to 180- to 200-base pair ladders after 4 h. Higher-order chromatin damage, producing 50-kilobase DNA fragments, occurred within 2 h. Significant DNA strand breaks were seen in attached cells within 1 h incubation with > or = 1 ng LPS/ml, using in situ labeling by break extension (ISBE). DNA strand breakage in attached cells peaked after 2 h and remained elevated after 4 h. Detachment of SPAEC from the monolayer did not begin until 4 h. SPAEC cultured on collagen were protected from LPS-induced apoptosis; DNA damage measured by IDF, high-molecular-weight DNA fragmentation, and ISBE were suppressed. The protective effect of collagen was not due to inactivation of LPS. Thus LPS-induced apoptosis occurs in SPAEC after genotoxic damage and this process is suppressed by the extracellular matrix.

Adhesion to fibronectin via β1 integrins regulates p27kip1 levels and contributes to cell adhesion mediated drug resistance (CAM-DR)

“…This system also allows us to Similar to our ®ndings for myeloma cells, Sethi et al (1999) recently reported that binding of small cell lung cancer cell lines to FN via b1 integrins conferred resistance to DNA damaging drugs. Furthermore Hoyt et al (1996) demonstrated that adhesion to ®bronectin protected tumor-derived endothelial cells from VP-16 induced double-strand breaks suggesting that adhesion could also protect cells responsible for the vascularization of the tumor. Collectively, these data indicate that b1 integrins may represent a cell surface pathway capable of protecting cells from drug induced cytotoxicity.…”

Lipopolysaccharide Signals an Endothelial Apoptosis Pathway Through TNF Receptor-Associated Factor 6-Mediated Activation of c-Jun NH2-Terminal Kinase

“…However, it is also clear that LPS has direct effects on the endothelium (53)(54)(55)(56)(57). As with TNF, in most studies LPS does not induce significant death of human endothelial cells unless new gene expression is blocked (3,6).…”

Role of the tumor microenvironment in mediating de novo resistance to drugs and physiological mediators of cell death

“…Presumably, fibronectin adhesion reduced the availability of topo IIb for forming drug-induced cleavable complexes. Similarly, Hoyt et al (1996) also demonstrated that activation of b1 integrins in tumor derived endothelial cells or lung endothelial cells resulted in a decrease in etoposide-and bleomycininduced DNA damage (Jones et al, 2001). Moreover, in the cell spheroid model resistance associated with topoisomerase II inhibitors also correlated with a decrease in DNA damage compared to cells grown as a monolayer (Oloumi et al, 2000).…”