Phenothiazine neuroleptics signal to the human insulin promoter as revealed by a novel high-throughput screen.
A number of diabetogenic stimuli interact to influence insulin promoter activity, making it an attractive target for both mechanistic studies and therapeutic interventions. High-throughput screening (HTS) for insulin promoter modulators has the potential to reveal novel inputs into the control of that central element of the pancreatic beta-cell. A cell line from human islets in which the expression of insulin and other beta-cell-restricted genes are modulated by an inducible form of the bHLH transcription factor E47 was developed. This cell line, T6PNE, was adapted for HTS by transduction with a vector expressing green fluorescent protein under the control of the human insulin promoter. The resulting cell line was screened against a library of known drugs for those that increase insulin promoter activity. Members of the phenothiazine class of neuroleptics increased insulin gene expression upon short-term exposure. Chronic treatment, however, resulted in suppression of insulin promoter activity, consistent with the effect of phenothiazines observed clinically to induce diabetes in chronically treated patients. In addition to providing insights into previously unrecognized targets and mechanisms of action of phenothiazines, the novel cell line described here provides a broadly applicable platform for mining new molecular drug targets and central regulators of beta-cell differentiated function.
Kiselyuk
Alice
A
Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA.
Farber-Katz
Suzette
S
Cohen
Tom
T
Lee
Seung-Hee
SH
Geron
Ifat
I
Azimi
Behrad
B
Heynen-Genel
Susanne
S
Singer
Oded
O
Price
Jeffrey
J
Mercola
Mark
M
Itkin-Ansari
Pamela
P
Levine
Fred
F
D014150:Antipsychotic Agents / Q000494:pharmacology*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D050761:Cyclin-Dependent Kinase Inhibitor p57 / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D057166:High-Throughput Screening Assays / Q000379:methods*; D006801:Humans; D007328:Insulin / Q000235:genetics*; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000378:metabolism; D010640:Phenothiazines / Q000494:pharmacology*; D011401:Promoter Regions, Genetic; D015398:Signal Transduction / Q000187:drug effects*; D013329:Structure-Activity Relationship; D051820:TCF Transcription Factors / Q000235:genetics / Q000378:metabolism; D058125:Transcription Factor 7-Like 1 Protein
D014150:Antipsychotic Agents; C493964:CDKN1C protein, human; D050761:Cyclin-Dependent Kinase Inhibitor p57; D007328:Insulin; D010640:Phenothiazines; D051820:TCF Transcription Factors; C544912:TCF7L1 protein, human; D058125:Transcription Factor 7-Like 1 Protein; C084820:profenamine; C031637:phenothiazine