Expression and growth-promoting function of the IL-8 receptor beta in human melanoma cells.
The chemokine GRO alpha is an autocrine growth factor for melanoma cells. Although GRO alpha has been identified as a high affinity ligand for the IL-8 receptor beta (IL-8R beta) in recombinant systems, the receptor mediating its action in melanoma cells has been a matter of debate. Here, we show by reverse transcription and PCR expression of IL-8R beta, mRNA transcripts in different melanoma cell lines and in normal human melanocytes. To characterize the role of the IL-8R beta in melanoma cells, antiserum was raised in rabbits against a fusion protein containing the NH2-terminal portion of the receptor. Its specificity was shown by flow cytometry with IL-8R beta-transfected HL60 cells. A specific epitope could be mapped with IL-8R beta mutants to the peptide sequence between ASP-4 and ASP-14 of this receptor. Binding studies with [125I]GRO alpha in IL-8R beta transfectants indicated ligand antagonistic properties of this Ab. Expression of IL-8R beta protein at the cell surface of various melanoma cell lines could be shown by flow cytometry with F(ab')2 fragments of the IL-8R beta antiserum. Moreover, anti-IL-8R beta Ab partially blocked specific binding of [125I]GRO alpha in various melanoma cell lines. Addition of F(ab')2 fragments of the IL-8R beta antiserum or of neutralizing anti-GRO alpha mAb to different melanoma cell lines identified this GRO alpha-IL-8R beta interaction as a major component required for serum-independent melanoma cell growth.
Norgauer
J
J
Clinic of Dermatology, University of Freiburg, Germany.
Metzner
B
B
Schraufstätter
I
I
D015703:Antigens, CD / Q000276:immunology / Q000502:physiology*; D001483:Base Sequence; D001667:Binding, Competitive / Q000276:immunology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D054360:Chemokine CXCL1; D019743:Chemokines, CXC; D002630:Chemotactic Factors / Q000502:physiology; D006133:Growth Substances / Q000276:immunology / Q000502:physiology*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008545:Melanoma / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D008969:Molecular Sequence Data; D018123:Receptors, Interleukin / Q000276:immunology / Q000502:physiology*; D023062:Receptors, Interleukin-8A; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; C475829:CXCL1 protein, human; D054360:Chemokine CXCL1; D019743:Chemokines, CXC; D002630:Chemotactic Factors; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D018123:Receptors, Interleukin; D023062:Receptors, Interleukin-8A