The role of protein kinase C (PKC) in interleukin-1beta-(Il-1beta)-, tumor necrosis factor-alpha- (TNF-alpha)-, and lipopolysaccharide- (LPS)-induced vascular cell adhesion molecule-1 (VCAM-1) expression on human umbilical vein endothelial cells (HUVEC) was studied. PKC inhibition or downregulation diminished VCAM-1 mRNA accumulation and protein expression. Interleukin-1beta, TNF-alpha, and LPS induce nuclear factor (NF)-kappaB-like binding activity, which precedes VCAM-1 transcription. PKC inhibition did not prevent NF-kappaB-like binding activity, indicating that this is PKC-independent, and NF-kappaB-like binding activity is insufficient for transcription of VCAM-1.