Overexpression of CXC-chemokines and CXC-chemokine receptor type II constitute an autocrine growth mechanism in the epidermoid carcinoma cells KB andA431

The CXC-chemokines Gro alpha and interleukin-8 (IL-8) are well characterize d growth factors for melanoma cells. Here the constitutive expression of Gr oa, IL-8 and their receptors (CXCR1 and CXCR2) as well as their functional involvement in the proliferation response were analyzed in normal keratinoc ytes and epidermoid carcinoma cell lines A431 and KB. Flow cytometric measu rements, ELISA and semi-quantitative RT-PCR revealed low constitutive prote in secretion and mRNA expression of both CXC-chemokines as well as CXCR1 an d 2 in normal keratinocytes, whereas significant higher levels of CXC-chemo kines and CXCR2 were deteced in epidermoid carcinoma cells. Proliferation o f epidermoid carcinoma cells could be induced by CXC-chemokines and constit utive proliferation could be inhibited by neutralizing antibodies against C XC-chemokines and CXCR2. These studies indicate that constitutive Gro alpha , IL-8 and CXCR2 protein expression enable an autocrine growth mechanism in epidermoid carcinoma cells.