Pharmacological analysis of CCK2 receptors up-regulated using engineered transcription factors.
Designed zinc finger proteins (ZFPs) regulate expression of target genes when coupled to activator or repressor domains. Transfection of ZFPs into cell lines can create expression systems where the targeted endogenous gene is transcribed and the protein of interest can be investigated in its own cellular context. Here we describe the pharmacological investigation of an expression system generated using CCK2 receptor-selective ZFPs transfected into human embryonic kidney cells (HEKZFP system). The receptors expressed in this system, in response to ZFP expression, were functional in calcium mobilization studies and the potency of the agonists investigated was consistent with their action at CCK2 receptors (CCK-8S pA50 = 9.05+/-0.11, pentagastrin pA50 = 9.11+/-0.13). In addition, binding studies were conducted using [125I]-BH-CCK-8S as radioligand. The saturation binding analysis of this radioligand was consistent with a single population of high affinity CCK receptors (pK(D) = 10.24). Competition studies were also conducted using a number of previously well-characterized CCK-receptor selective ligands; JB93182, YF476, PD-134,308, SR27897, dexloxiglumide, L-365,260 and L-364,718. Overall, the estimated affinity values for these ligands were consistent with their interaction at CCK2 receptors. Therefore, CCK2 receptors up-regulated using zinc finger protein technology can provide an alternative to standard transfection techniques for the pharmacological analysis of compounds.
Morton
Magda F
MF
Johnson & Johnson Pharmaceutical Research & Development, LLC., 3210 Merryfield Row, San Diego, CA, 92121, USA. mmorton1@prdus.jnj.com
Liu
Pei-Qi
PQ
Reik
Andreas
A
de la Rosa
Ragan
R
Mendel
Matthew
M
Li
Xiao-Yong
XY
Case
Casey
C
Pabo
Carl
C
Moreno
Veronica
V
Pyati
Jayashree
J
Shankley
Nigel P
NP
D002460:Cell Line; D004353:Drug Evaluation, Preclinical / Q000379:methods; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000378:metabolism*; D008024:Ligands; D004364:Pharmaceutical Preparations / Q000378:metabolism; D043887:Receptor, Cholecystokinin B / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D015854:Up-Regulation / Q000187:drug effects* / Q000235:genetics; D016335:Zinc Fingers / Q000235:genetics / Q000502:physiology
D008024:Ligands; D004364:Pharmaceutical Preparations; D043887:Receptor, Cholecystokinin B; D014157:Transcription Factors