Use of RT-PCR to detect co-expression of neuropeptides and their receptorsin lung cancer

Small-cell lung cancer (SCLC) synthesises a wide range of neuropeptides and their corresponding receptors. Together, these call form autocrine growth loops. Non-small-cell lung cancer (NSCLC) does not generally share this neu roendocrine phenotype. In this study, we tested the hypothesis that multipl e neuropeptides and their receptors are co-expressed in SCLC, constituting potential autocrine loops. Expression of mRNA for arginine vasopressin, gas trin, cholecystokinin, gastrin-releasing peptide, endothelin and neurotensi n, together with their cognate receptors, was evaluated by reverse traascri ptase-polymerase chain reaction (RT-PCR) in a panel of human lung cancer ce ll lines. We have assessed those neuropeptides and neuropeptide receptors t hat could be used as potential early markers to detect lung cancer cells bo th as micrometastases in blood and within dysplasia in bronchial biopsies. We establish that although no cell line expressed all neuropeptides, co-exp ression of neuropeptides and their receptors is common in SCLC but not in N SCLC. We conclude that mRNA for the neuropeptides gastrin-releasing peptide and arginine vasopressin and the cholecystokinin receptor B were most SCLC -specific and RT-PCR for these markers could be used to distinguish between SCLC and NSCLC. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved .