Palmer, Melissa

The AML14 cell line and its AML14.3D10 subclone was established as a model cell system that exhibits phenotypic characteristics similar to that of human eosinophils. We investigated the effects of purinergic receptor stimulation on the physiological response of the AML 14.3D10 cell line to better evaluate its role as a suitable model for eosinophils using both molecular and functional approaches. Ca 2+ imaging experiments using Fura‐2 demonstrated the existence of purinergic receptors responsive to UTP (EC 50 of 8.9 x 10 −8 ), ATP γ‐s (EC 50 of 1.87 x 10 −7 ), and UDP (EC 50 of 7.44x 10 −6 ). Molecular identification of the purinergic receptor subtypes was confirmed by QRT‐PCR which demonstrated the presence of P2Y 1 , P2Y 2 , P2Y 4 , and P2Y 6 receptors. Ratio imaging experiments using the membrane potential sensitive indicator DiBAC‐3 showed that stimulation with UTP produced a membrane hyperpolarization of approximately 10 mV that returned to the original resting potential within 10 minutes after stimulation. Whole cell perforated patch clamp experiments using amphotericin B revealed the presence of voltage‐gated potassium channel currents that were stimulated following treatment with UTP. Analysis of mRNA by QRT‐PCR indicated the existence of several voltage‐gated potassium channel α subunits including, Kv1.2, Kv1.3, Kv1.4, and Kv1.6. Previous studies of Kv1.3 channel function in T‐lymphocytes showed that the channel was involved in activation and proliferation, suggesting the possibility of a similar role related to tumorogenesis in the AML 14.3D10 cell line.