Multifunctional roles of PKCδ: Opportunities for targeted therapy in human disease

Area of Science:

• Cellular Biology
• Molecular Oncology
• Biochemistry

Background:

• Protein kinase C-delta (PKCδ) is a serine-threonine kinase with a newly recognized dual role in regulating cell death and proliferation.
• Studies in knockout mice reveal PKCδ's pro-apoptotic function in response to DNA damage and its role as a tumor promoter in certain cancers.
• PKCδ acts upstream of apoptotic pathways, as inhibiting it suppresses cytochrome c release and caspase activation in non-transformed cells.

Purpose of the Study:

• To review the current understanding of PKCδ's biological functions.
• To explore the prospects of targeting PKCδ for therapeutic interventions in human diseases.
• To elucidate the regulatory mechanisms underlying PKCδ's distinct roles in cell death and proliferation.

Main Methods:

• Review of existing literature and studies involving PKCδ knockout mice.
• Analysis of data on PKCδ expression in human breast cancer subtypes.
• Examination of cellular assays investigating apoptotic pathway regulation.

Main Results:

• PKCδ deficiency protects against DNA damage-induced and physiological apoptosis.
• PKCδ inhibition reduces irradiation and chemotherapy-induced toxicity.
• PKCδ acts as a tumor promoter in mouse models of mammary gland and lung cancer.
• Elevated PKCδ expression correlates with poor prognosis in Her2+ and other breast cancer subtypes.

Conclusions:

• PKCδ exhibits opposing roles, acting as a pro-apoptotic factor and a tumor promoter.
• Targeting PKCδ presents a therapeutic opportunity for managing treatment toxicity.
• Further research into PKCδ regulation is crucial for developing effective cancer therapies.