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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

Structures of known CRAC channel inhibitors.
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fig1: Structures of known CRAC channel inhibitors.

Mentions: Thus far, a variety of small molecules blocking the CRAC channel have been identified, such as the imidazole derivative, SKF96365 (IC50 of approximately 4 μmol/L)15,16, 2-APB [at low concentrations of 1–5 μmol/L, 2-APB potentiates CRAC currents, whereas high concentrations (>10 μmol/L) cause a transient enhancement of CRAC currents followed by a complete block in S2 for mammalian cells]17,18, YM58483 (IC50 of approximately 150 nmol/L after 24 h of preincubation; IC50 of approximately 10 μmol/L immediately after addition)19,20, and Synta 66 (IC50 of approximately 3 μmol/L)21 (Figure 1); however, these compounds are not specific because they interfere with a variety of other transport processes. The only specific CRAC channel inhibitor tested in human is CM248922, the structure of which has not yet been disclosed. Recent studies have suggested that blocking CRAC channel activity by inhibiting STIM1 may inadvertently affect other channels23. Moreover, STIM1 mutations are associated with a syndrome of immunodeficiency and autoimmunity, whereas ORAI1 mutations cause only a major clinical syndrome of immunodeficiency24. Therefore, molecules that specifically block ORAI1 may have fewer side effects compared with molecules that target STIM1. This is the focus and priority of CRAC channel research (Figure 1).


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)

Structures of known CRAC channel inhibitors.
© Copyright Policy
Related In: Results  -  Collection

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

fig1: Structures of known CRAC channel inhibitors.
Mentions: Thus far, a variety of small molecules blocking the CRAC channel have been identified, such as the imidazole derivative, SKF96365 (IC50 of approximately 4 μmol/L)15,16, 2-APB [at low concentrations of 1–5 μmol/L, 2-APB potentiates CRAC currents, whereas high concentrations (>10 μmol/L) cause a transient enhancement of CRAC currents followed by a complete block in S2 for mammalian cells]17,18, YM58483 (IC50 of approximately 150 nmol/L after 24 h of preincubation; IC50 of approximately 10 μmol/L immediately after addition)19,20, and Synta 66 (IC50 of approximately 3 μmol/L)21 (Figure 1); however, these compounds are not specific because they interfere with a variety of other transport processes. The only specific CRAC channel inhibitor tested in human is CM248922, the structure of which has not yet been disclosed. Recent studies have suggested that blocking CRAC channel activity by inhibiting STIM1 may inadvertently affect other channels23. Moreover, STIM1 mutations are associated with a syndrome of immunodeficiency and autoimmunity, whereas ORAI1 mutations cause only a major clinical syndrome of immunodeficiency24. Therefore, molecules that specifically block ORAI1 may have fewer side effects compared with molecules that target STIM1. This is the focus and priority of CRAC channel research (Figure 1).

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