Barnett CC, Moore EE, Silliman CC, Abdalla EK, Partrick DA, Curley SA. Cytosolic phospholipase A(2)-mediated ICAM-1 expression is calcium dependent.
J Surg Res 2001;
99:307-10. [PMID:
11469902 DOI:
10.1006/jsre.2001.6188]
[Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND
Some human malignancies such as virus-related hepatocellular cancer arise in a setting of chronic inflammation. Upregulation of ICAM-1 is a seminal late event in malignant transformation following chronic inflammation. Cytosolic phospholipase A(2) (cPLA(2)) is a lipid-mediator activated by inflammatory stimuli, which has been shown to mediate ICAM-1 upregulation. As lipid mediators are known to work via calcium-dependent mechanisms in nearly all mammalian cells, we hypothesize that inflammatory-mediated ICAM-1 upregulation is dependent on both cPLA(2) and intracellular calcium.
MATERIALS AND METHODS
HUVEC were chosen as a representative cell line as they emulate hepatic sinusoids and are a well-established cell model. These were grown to confluence in T-25 flasks and stimulated with TNF-alpha or LPS for 6 h. Additional groups were preincubated with AACOCF3 (a specific cPLA(2) inhibitor) or BAPTA A.M. (a specific inhibitor of intracellular Ca(2+)) prior to being exposed to inflammatory stimuli. ICAM-1 expression was determined by mean fluorescent intensity (MFI) as measured by FITC-labeled moAb to ICAM-1 via FACS. The role of intracellular Ca(2+) on cPLA(2) activity was determined by thin-layer chromatography. Groups were compared using ANOVA with Scheffe's post hoc analysis; *P < 0.05 vs control, daggerP < 0.05 vs LPS and TNF-alpha was considered significant; N > or = 4 all experimental groups.
RESULTS
Both cPLA(2) and Ca(2+) inhibition significantly inhibited inflammatory upregulation of ICAM-1. Pretreatment with BAPTA A.M. attenuated HUVEC cPLA(2) activity in response to LPS. These findings suggest that appropriate molecular target suppression may prevent malignant degeneration in the presence of chronic inflammation.
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