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6-Br-5methylindirubin-3′oxime (5-Me-6-BIO) targeting the leishmanial glycogen synthase kinase-3 (GSK-3) short form affects cell-cycle progression and induces apoptosis-like death: Exploitation of GSK-3 for treating leishmaniasis

Xingi, Evangelia and Smirlis, Despina and Myrianthopoulos, Vassilios and Prokopios, Magiatis and Grant, Karen and Meijer, Laurent and Mikros, Emmanuel and Skaltsounis, Alexios-Leandros and Soteriadou, Ketty (2009) 6-Br-5methylindirubin-3′oxime (5-Me-6-BIO) targeting the leishmanial glycogen synthase kinase-3 (GSK-3) short form affects cell-cycle progression and induces apoptosis-like death: Exploitation of GSK-3 for treating leishmaniasis. International Journal of Parasitology, 39 (12). pp. 1289-1303. ISSN 0020-7519

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    Abstract

    Indirubins known to target mammalian cyclin-dependent kinases (CDKs) and glycogen synthase kinase (GSK-3) were tested for their antileishmanial activity. 6-Br-indirubin-3'-oxime (6-BIO), 6-Br-indirubin-3'acetoxime and 6-Br-5methylindirubin-3'oxime (5-Me-6-BIO) were the most potent inhibitors of L. donovani promastigote and amastigote growth (IC50 values ≤ 1.2 μM). Since the 6-Br substitution on the indirubin backbone greatly enhances the selectivity for mammalian GSK-3 over CDKs, we identified the leishmanial GSK-3 homologues, a short (LdGSK-3s) and a long one, focusing on LdGSK-3s which is closer to human GSK-3β for further studies. Kinase assays showed that 5-Me-6-BIO inhibited LdGSK-3s more potently than CRK3 (the CDK1 homologue in Leishmania), while 6-BIO was more selective for CRK3. Promastigotes treated with 5-Me-6-BIO accumulated in the S and G2/M cell-cycle phases and underwent apoptosis-like death. Interestingly, these phenotypes were completely reversed in parasites over-expressing LdGSK-3s. This finding strongly supports that LdGSK-3s is a) the intracellular target of 5-Me-6-BIO and b) involved in cell-cycle control and in pathways leading to apoptosis-like death. 6-BIO treatment induced a G2/M arrest, consistent with inhibition of CRK3, and apoptosis-like death. These effects were partially reversed in parasites over-expressing LdGSK-3s suggesting that in vivo 6-BIO may also target LdGSK-3s. Molecular docking of 5-Me-6-BIO in CRK3 and 6-BIO in human GSK-3β and LdGSK-3s active sites predict the existence of functional/structural differences that are sufficient to explain the observed difference in their affinity. In conclusion, LdGSK-3s is validated as a potential drug target in Leishmania and could be exploited for the development of selective indirubin-based leishmanicidals.

    Item Type: Article
    Journal or Publication Title: International Journal of Parasitology
    Uncontrolled Keywords: L. donovani glycogen synthase kinase-3 short ; 5-Me-6-BIO ; 6-BIO ; indirubins ; apoptosis-like death ; drug target
    Subjects: Q Science > QH Natural history > QH301 Biology
    Departments: UNSPECIFIED
    ID Code: 26198
    Deposited By: Dr Karen Grant
    Deposited On: 09 Apr 2009 08:58
    Refereed?: Yes
    Published?: Published
    Last Modified: 23 Jul 2014 14:48
    Identification Number:
    URI: http://eprints.lancs.ac.uk/id/eprint/26198

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