Abstract: Objective To determine whether leflunomide could control the proinflammatory cytokine expression induced by anthralin via inhibiting the activation of nuclear factor κB (NF-κB).Methods The expression of NF-κB inhibitory protein α (IκBα),was analyzed by using Western blot method.MTT assay and RT-PCR were used to assess the proliferating activity and mRNA expression of intercellular adhesion molecule-1 (ICAM-1) of HaCaT keratinocytes,respectively.Results Leflunomide inhibited the degradation of IκBα by anthralin,i.e.the activation of NF-κB signaling pathway,in a dose-dependent manner.The inhibition of keratinocyte growth by anthralin did not correlate with the activation of NF-κB.Under the experimental conditions used,leflunomide was shown to be able to significantly inhibit the over-expression of ICAM-1 on keratinocytes induced by anthralin;this inhibition occurred in a dose dependent manner.Conclusions Growth inhibition by topical anti-psoriatic medication anhtralin is unrelated to the NF-κB-dependent signaling pathway,and leflunomide can control ICAM-1 expression induced by anthralin via inhibiting the activation of NF-κB.

Key words: Intercellular adhesion molecule-1, NF-kappa B, Keratinocytes, Leflunomide, Anthralin