Effects of interleukin-1alpha, interleukin-1 receptor antagonist, and neutralizing antibody on proinflammatory cytokine expression by human squamous cell carcinoma lines

Abstract

Proinflammatory cytokines interleukin (IL)-1alpha, IL-6, IL-8, and granulocyte macrophage colony-stimulating factor (GM-CSF) have been detected in tumor specimens and primary cell cultures from patients with head and neck squamous cell carcinoma. IL-1alpha has been reported to play an important role in inducing the expression of cytokines IL-6, IL-8, and GM-CSF during inflammation. We examined whether these cytokines are expressed together in five primary and seven established UM-SCC cell lines, and we also examined the effects of IL-1alpha, IL-1 receptor antagonist or neutralizing antibody (Ab) upon expression of this repertoire of proinflammatory cytokines in established UM-SCC lines. Secretion of proinflammatory cytokines IL-1alpha, IL-6, IL-8, and GM-CSF was detected by ELISA in both the primary and established UM-SCC lines. Constitutive expression of specific mRNAs for these cytokines was confirmed in the UM-SCC lines by reverse transcriptase-PCR and Northern blot analysis. Addition of recombinant IL (rIL)-1alpha but not rIL-6 induced a dose-dependent increase in IL-8 and GM-CSF production. IL-1 receptor antagonist (IL-RA) or anti-IL-1 neutralizing Ab could completely inhibit the rIL-1alpha-inducible increase in IL-8 and GM-CSF expression, but the inhibitors had a negligible effect on the constitutive level of production of the cytokines. Transfer and expression of the IL-1alpha gene in a low-cytokine-producing cell line, UM-SCC-38, induced IL-8 and GM-CSF expression, but this expression was also not inhibited by IL-1RA or anti-IL-1 neutralizing Ab. We conclude that IL-1alpha can enhance the expression of cytokines IL-8 and GM-CSF in UM-SCC cell lines but that constitutive expression of these cytokines by UM-SCC is not inhibited by exogenous IL-1RA or neutralizing Ab.