Targeting the cysteine rich domain of protein kinase C

Project: Research project

Project Details

Description

DESCRIPTION: (provided by applicant)

Mammary carcinogenesis in response to oncogenes is associated with the
regulation of multiple signaling kinase cascades linked to cellular
mitogenesis. An innovative and effective therapeutic approach would be to
target a domain that is common among multiple signaling kinases. One such
domain is the cysteine rich domain (CRD), which modulates intermolecular
lipid-protein interactions. CRD domains are present in a large variety of
proteins including protein kinase C (PKC),which are critical determinants in
breast cancer tumorigenicity and metastasis. PKC is a family of phospholipid-
regulated, serine/threonine, kinases that transduces oncogenic signals in
breast cancer cells. Therefore, the CRD of PKC may be an important
pharmacological target for therapeutic intervention in malignant
transformation and progression of breast cancer. D-erythro-N,N-dimethyl-
sphingosine (DMS) is a naturally derived sphingomyelin metabolite, which has
been shown to inhibit total PKC activity; although the exact molecular
mechanism is not known. Our preliminary studies demonstrate that DMS directly
inhibits multiple isoforms of PKC activity, suggesting a common mechanism by
which DMS recognizes and specifically binds to a conserved domain of PKC
isoforms. To minimize interpretation problems, we have chosen to investigate
PKC zeta (z) , which contains only one CRD. We have investigated inhibition of
PKC z through the CRD as a model system for DMS-induced growth inhibition
and/or apoptosis in breast cancer cells. It is hypothesized that DMS
specifically binds to the CRD and inactivates PKC z, blocking breast cancer
cell invasion and growth. This hypothesis will be investigated using
combinations of biochemical, biophysical and molecular experimental
approaches. We will first determine the DMS-binding site within CRD using
site-directed- and deletion-mutants of PKC z. Second, we will identify the
molecular determinants of DMS that mediate interactions with the CRD. Using
several analogues of DMS, we will determine the critical molecular structure
of DMS that directly interacts with the CRD. Establishing CRD as a molecular
target for lipid-derived agents or lipomimetics may lead to potential
therapies that simultaneously block multiple pro-survival and pro-mitogenic
signaling cascades without appreciable immunological and inflammatory side
effects.
StatusFinished
Effective start/end date7/1/016/30/04

Funding

  • National Cancer Institute: $153,900.00
  • National Cancer Institute: $153,900.00