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Discovery of a Small-Molecule Protein Kinase Cδ-selective Activator With Promising Application in Colon Cancer Therapy

Cláudia Bessa, Joana Soares, Liliana Raimundo, Joana B Loureiro, Célia Gomes, Flávio Reis, Miguel L Soares, Daniel Santos, Chetna Dureja, Saumya R Chaudhuri, Cynthia Lopez-Haber, Marcelo G Kazanietz, Jorge Gonçalves, etc.

Cell Death Dis. 2018 Jan 18;9(2):23.

PMID: 29348560

Abstract:

Protein kinase C (PKC) isozymes play major roles in human diseases, including cancer. Yet, the poor understanding of isozymes-specific functions and the limited availability of selective pharmacological modulators of PKC isozymes have limited the clinical translation of PKC-targeting agents. Here, we report the first small-molecule PKCδ-selective activator, the 7α-acetoxy-6β-benzoyloxy-12-O-benzoylroyleanone (Roy-Bz), which binds to the PKCδ-C1-domain. Roy-Bz potently inhibited the proliferation of colon cancer cells by inducing a PKCδ-dependent mitochondrial apoptotic pathway involving caspase-3 activation. In HCT116 colon cancer cells, Roy-Bz specifically triggered the translocation of PKCδ but not other phorbol ester responsive PKCs. Roy-Bz caused a marked inhibition in migration of HCT116 cells in a PKCδ-dependent manner. Additionally, the impairment of colonosphere growth and formation, associated with depletion of stemness markers, indicate that Roy-Bz also targets drug-resistant cancer stem cells, preventing tumor dissemination and recurrence. Notably, in xenograft mouse models, Roy-Bz showed a PKCδ-dependent antitumor effect, through anti-proliferative, pro-apoptotic, and anti-angiogenic activities. Besides, Roy-Bz was non-genotoxic, and in vivo it had no apparent toxic side effects. Collectively, our findings reveal a novel promising anticancer drug candidate. Most importantly, Roy-Bz opens the way to a new era on PKC biology and pharmacology, contributing to the potential redefinition of the structural requirements of isozyme-selective agents, and to the re-establishment of PKC isozymes as feasible therapeutic targets in human diseases.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
IAR42411920 Protein Kinase Cδ isozyme human Protein Kinase Cδ isozyme human Price
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