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Discovery and structural optimization of 1-phenyl-3-(1-phenylethyl)urea derivatives as novel inhibitors of CRAC channel.

Zhang HZ, Xu XL, Chen HY, Ali S, Wang D, Yu JW, Xu T, Nan FJ - Acta Pharmacol. Sin. (2015)

Bottom Line: SAR study on its derivatives showed that the alkyl substituent on the α-position of the left-side benzylic amine (R1) was essential for Ca(2+) influx inhibition and that the S-configuration was better than the R-configuration.The derivatives in which the right-side R3 was substituted by an electron-donating group showed more potent inhibitory activity than those that were substituted by electron-withdrawing groups.Furthermore, the free N-H of urea was not necessary to maintain the high potency of Ca(2+) influx inhibition.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Drug Research, The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.

ABSTRACT

Aim: Ca(2+)-release-activated Ca(2+) (CRAC) channel, a subfamily of store-operated channels, is formed by calcium release-activated calcium modulator 1 (ORAI1), and gated by stromal interaction molecule 1 (STIM1). CRAC channel may be a novel target for the treatment of immune disorders and allergy. The aim of this study was to identify novel small molecule CRAC channel inhibitors.

Methods: HEK293 cells stably co-expressing both ORAI1 and STIM1 were used for high-throughput screening. A hit, 1-phenyl-3-(1-phenylethyl)urea, was identified that inhibited CRAC channels by targeting ORAI1. Five series of its derivatives were designed and synthesized, and their primary structure-activity relationships (SARs) were analyzed. All derivatives were assessed for their effects on Ca(2+) influx through CRAC channels on HEK293 cells, cytotoxicity in Jurkat cells, and IL-2 production in Jurkat cells expressing ORAI1-SS-eGFP.

Results: A total of 19 hits were discovered in libraries containing 32 000 compounds using the high-throughput screening. 1-Phenyl-3-(1-phenylethyl)urea inhibited Ca(2+) influx with IC50 of 3.25±0.17 μmol/L. SAR study on its derivatives showed that the alkyl substituent on the α-position of the left-side benzylic amine (R1) was essential for Ca(2+) influx inhibition and that the S-configuration was better than the R-configuration. The derivatives in which the right-side R3 was substituted by an electron-donating group showed more potent inhibitory activity than those that were substituted by electron-withdrawing groups. Furthermore, the free N-H of urea was not necessary to maintain the high potency of Ca(2+) influx inhibition. The N,N'-disubstituted or N'-substituted derivatives showed relatively low cytotoxicity but maintained the ability to inhibit IL-2 production. Among them, compound 5b showed an improved inhibition of IL-2 production and low cytotoxicity.

Conclusion: 1-Phenyl-3-(1-phenylethyl)urea is a novel CRAC channel inhibitor that specifically targets ORAI1. This study provides a new chemical scaffold for design and development of CRAC channel inhibitors with improved Ca(2+) influx inhibition, immune inhibition and low cytotoxicity.

No MeSH data available.


Related in: MedlinePlus

Structure of original hit compound 1.
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fig2: Structure of original hit compound 1.

Mentions: To identify small chemical molecules that block CRAC channel activity, we established an ORAI1 and STIM1 stably co-expressed single-cell clone human embryonic kidney 293 (HEK293) cell line and performed high-throughput screening of libraries containing 32 000 compounds using a fluorescence assay of Ca2+ influx. The average Z-factor of the screen was approximately 0.74, and the coefficient of variation was 4.7%. Hits in the screen were defined by a significantly reduced cytosolic Ca2+ level [inhibition rate ≥MEAN (signal means) +3×STDEV (standard deviations)] elevated by thapsigargin (TG). A total of 19 hits were identified in the screen. Of these, 8 compounds were lanthanide complexes, 3 compounds showed strong cytotoxicity, and 2 compounds exhibited weak inhibition using the patch clamp technique. We selected compound 1 from the remaining 6 compounds because this compound presents a novel chemical scaffold and good drug-like properties, which makes it different from the known CRAC channel inhibitors. In this study, we synthesized a series of structure closed analogs (2a-2h, 3a-3l, 4a-4j, and 5a-5j), with modifications of the left-side benzylamine subunit and right-side phenyl subunit of compound 1, and determined the primary structure-activity relationships (SARs). Several compounds showed improved potency and immune inhibitory activity. Compound 1 inhibits the CRAC channel by specifically targeting the ORAI1 protein. We propose this derivative as a potential scaffold for developing novel CRAC channel inhibitors (Figure 2).


Discovery and structural optimization of 1-phenyl-3-(1-phenylethyl)urea derivatives as novel inhibitors of CRAC channel.

Zhang HZ, Xu XL, Chen HY, Ali S, Wang D, Yu JW, Xu T, Nan FJ - Acta Pharmacol. Sin. (2015)

Structure of original hit compound 1.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4561970&req=5

fig2: Structure of original hit compound 1.
Mentions: To identify small chemical molecules that block CRAC channel activity, we established an ORAI1 and STIM1 stably co-expressed single-cell clone human embryonic kidney 293 (HEK293) cell line and performed high-throughput screening of libraries containing 32 000 compounds using a fluorescence assay of Ca2+ influx. The average Z-factor of the screen was approximately 0.74, and the coefficient of variation was 4.7%. Hits in the screen were defined by a significantly reduced cytosolic Ca2+ level [inhibition rate ≥MEAN (signal means) +3×STDEV (standard deviations)] elevated by thapsigargin (TG). A total of 19 hits were identified in the screen. Of these, 8 compounds were lanthanide complexes, 3 compounds showed strong cytotoxicity, and 2 compounds exhibited weak inhibition using the patch clamp technique. We selected compound 1 from the remaining 6 compounds because this compound presents a novel chemical scaffold and good drug-like properties, which makes it different from the known CRAC channel inhibitors. In this study, we synthesized a series of structure closed analogs (2a-2h, 3a-3l, 4a-4j, and 5a-5j), with modifications of the left-side benzylamine subunit and right-side phenyl subunit of compound 1, and determined the primary structure-activity relationships (SARs). Several compounds showed improved potency and immune inhibitory activity. Compound 1 inhibits the CRAC channel by specifically targeting the ORAI1 protein. We propose this derivative as a potential scaffold for developing novel CRAC channel inhibitors (Figure 2).

Bottom Line: SAR study on its derivatives showed that the alkyl substituent on the α-position of the left-side benzylic amine (R1) was essential for Ca(2+) influx inhibition and that the S-configuration was better than the R-configuration.The derivatives in which the right-side R3 was substituted by an electron-donating group showed more potent inhibitory activity than those that were substituted by electron-withdrawing groups.Furthermore, the free N-H of urea was not necessary to maintain the high potency of Ca(2+) influx inhibition.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Drug Research, The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.

ABSTRACT

Aim: Ca(2+)-release-activated Ca(2+) (CRAC) channel, a subfamily of store-operated channels, is formed by calcium release-activated calcium modulator 1 (ORAI1), and gated by stromal interaction molecule 1 (STIM1). CRAC channel may be a novel target for the treatment of immune disorders and allergy. The aim of this study was to identify novel small molecule CRAC channel inhibitors.

Methods: HEK293 cells stably co-expressing both ORAI1 and STIM1 were used for high-throughput screening. A hit, 1-phenyl-3-(1-phenylethyl)urea, was identified that inhibited CRAC channels by targeting ORAI1. Five series of its derivatives were designed and synthesized, and their primary structure-activity relationships (SARs) were analyzed. All derivatives were assessed for their effects on Ca(2+) influx through CRAC channels on HEK293 cells, cytotoxicity in Jurkat cells, and IL-2 production in Jurkat cells expressing ORAI1-SS-eGFP.

Results: A total of 19 hits were discovered in libraries containing 32 000 compounds using the high-throughput screening. 1-Phenyl-3-(1-phenylethyl)urea inhibited Ca(2+) influx with IC50 of 3.25±0.17 μmol/L. SAR study on its derivatives showed that the alkyl substituent on the α-position of the left-side benzylic amine (R1) was essential for Ca(2+) influx inhibition and that the S-configuration was better than the R-configuration. The derivatives in which the right-side R3 was substituted by an electron-donating group showed more potent inhibitory activity than those that were substituted by electron-withdrawing groups. Furthermore, the free N-H of urea was not necessary to maintain the high potency of Ca(2+) influx inhibition. The N,N'-disubstituted or N'-substituted derivatives showed relatively low cytotoxicity but maintained the ability to inhibit IL-2 production. Among them, compound 5b showed an improved inhibition of IL-2 production and low cytotoxicity.

Conclusion: 1-Phenyl-3-(1-phenylethyl)urea is a novel CRAC channel inhibitor that specifically targets ORAI1. This study provides a new chemical scaffold for design and development of CRAC channel inhibitors with improved Ca(2+) influx inhibition, immune inhibition and low cytotoxicity.

No MeSH data available.


Related in: MedlinePlus