Molecular and functional characterization of PACAP/VIP receptors in Lewis lung carcinoma cells

Recent evidence suggests that the pleiotropic neuropeptide PACAP plays a role in cancer initiation, progression and metastasis. Here we explore expression patterns and functions of PACAP receptors in LLC1 cells. RT-PCR analysis revealed the expression of the PAC1 receptor splice variants PAC1null, PAC1 hip, PAC1 hop, PAC1 3a and PAC1s. No VPAC1 and only traces of VPAC2 mRNA were detectable. Measurement of cAMP by FRET live cell imaging with EPAC-camps1 revealed that the PAC1 receptors in LLC1 cells were functional and that PACAP binding was nearly irreversible with an EC50 of about 60 pM indicating high affinity…