title: Identification of small-molecule inhibitors of the colorectal cancer oncogene Krüppel-like factor 5 expression by ultrahigh-throughput screening.
abstract: The transcription factor Krüppel-like factor 5 (KLF5) is primarily expressed in the proliferative zone of the mammalian intestinal epithelium, where it regulates cell proliferation. Studies showed that inhibition of KLF5 expression reduces proliferation rates in human colorectal cancer cells and intestinal tumor formation in mice. To identify chemical probes that decrease levels of KLF5, we used cell-based ultrahigh-throughput screening (uHTS) to test compounds in the public domain of NIH, the Molecular Libraries Probe Production Centers Network library. The primary screen involved luciferase assays in the DLD-1/pGL4.18hKLF5p cell line, which stably expressed a luciferase reporter driven by the human KLF5 promoter. A cytotoxicity counterscreen was done in the rat intestinal epithelial cell line, IEC-6. We identified 97 KLF5-selective compounds with EC(50) < 10 μmol/L for KLF5 inhibition and EC(50) > 10 μmol/L for IEC-6 cytotoxicity. The two most potent compounds, CIDs (PubChem Compound IDs) 439501 and 5951923, were further characterized on the basis of computational, Western blot, and cell viability analyses. Both of these compounds, and two newly synthesized structural analogs of CID 5951923, significantly reduced endogenous KLF5 protein levels and decreased viability of several colorectal cancer cell lines without any apparent impact on IEC-6 cells. Finally, when tested in the NCI-60 panel of human cancer cell lines, compound CID 5951923 was selectively active against colon cancer cells. Our results show the feasibility of uHTS in identifying novel compounds that inhibit colorectal cancer cell proliferation by targeting KLF5.
authors: Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA. oberzyna@gmail.com
authors: Agnieszka B
authors: AB
authors: Bialkowska
authors: Melissa
authors: M
authors: Crisp
authors: Thomas
authors: T
authors: Bannister
authors: Yuanjun
authors: Y
authors: He
authors: Sarwat
authors: S
authors: Chowdhury
authors: Stephan
authors: S
authors: Schürer
authors: Peter
authors: P
authors: Chase
authors: Timothy
authors: T
authors: Spicer
authors: Franck
authors: F
authors: Madoux
authors: Chenlu
authors: C
authors: Tian
authors: Peter
authors: P
authors: Hodder
authors: Daniel
authors: D
authors: Zaharevitz
authors: Vincent W
authors: VW
authors: Yang
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D016000:Cluster Analysis; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D004354:Drug Screening Assays, Antitumor; D057166:High-Throughput Screening Assays; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000037:antagonists & inhibitors* / Q000235:genetics; D009857:Oncogenes; D051381:Rats; D015203:Reproducibility of Results; D015398:Signal Transduction / Q000187:drug effects; D054852:Small Molecule Libraries / Q000494:pharmacology* / Q000627:therapeutic use; D013329:Structure-Activity Relationship
chemical_list: D000970:Antineoplastic Agents; D051741:Kruppel-Like Transcription Factors; D054852:Small Molecule Libraries