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Identification of Kinase-substrate Pairs Using High Throughput Screening
11:13

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Protein kinase Calpha and epsilon small-molecule targeted therapeutics: a new roadmap to two Holy Grails in drug

Catherine A O'Brian1, Feng Chu, William G Bornmann

  • 1U.T. MD Anderson Cancer Center, Box 173, Houston, TX 77030, USA. cobrian@mdanderson.org

Expert Review of Anticancer Therapy
|February 1, 2006
PubMed

Insights

Targeting cancer involves inhibiting specific protein kinases (PKs). Researchers found modifying a key cysteine in PKCepsilon inactivates it, offering a new strategy for cancer therapeutics.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cancer Research

Background:

  • Protein kinase C (PKC) isoforms, specifically PKCalpha and PKCepsilon, are implicated as targets in cancer therapy.
  • Currently, there is a lack of targeted experimental therapeutics available to inhibit PKCalpha or PKCepsilon.

Purpose of the Study:

  • To investigate the potential of targeting an active-site cysteine in PKCepsilon for developing novel cancer therapeutics.
  • To explore the feasibility of designing small molecules that selectively inhibit PKCepsilon, PKCalpha, and other related PKC isozymes.

Main Methods:

  • Covalent modification of the active-site cysteine (Cys452) in human PKCepsilon using small molecules like 2-mercaptoethanolamine.
  • Analysis of kinase activity to determine the effect of covalent modification on PKCepsilon function.
  • Comparative analysis of Cys452 conservation across human protein kinase genes.

Main Results:

  • Covalent modification of Cys452 in human PKCepsilon was found to be necessary and sufficient to render the enzyme kinase-dead.
  • Cys452 was identified as a conserved residue in eleven other human protein kinase genes, including PKCalpha.
  • This conservation suggests a potential for broad applicability of the targeted inhibition strategy.

Conclusions:

  • Targeting the active-site cysteine (Cys452) of PKCepsilon with small molecules represents a viable strategy for developing kinase-dead inhibitors.
  • The design of small molecules with electrophile substituents positioned near Cys452 could lead to selective therapeutics for PKCepsilon, PKCalpha, and other related isozymes.
  • This approach holds promise for advancing targeted cancer therapy by inhibiting key PKC signaling pathways.

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