Protein kinase D2 is a novel regulator of glioblastoma growth and tumor formation.

Abstract

Glioblastoma multiforme, a highly aggressive tumor of the central nervous system, has a dismal prognosis that is due in part to its resistance to radio- and chemotherapy. The protein kinase C (PKC) family of serine threonine kinases has been implicated in the formation and proliferation of glioblastoma multiforme. Members of the protein kinase D (PKD) family, which consists of PKD1, -2 and, -3, are prominent downstream targets of PKCs and could play a major role in glioblastoma growth. PKD2 was highly expressed in both low-grade and high-grade human gliomas. The number of PKD2-positive tumor cells increased with glioma grading (P < .001). PKD2 was also expressed in CD133-positive glioblastoma stem cells and various glioblastoma cell lines in which the kinase was found to be constitutively active. Inhibition of PKDs by pharmacological inhibitors resulted in substantial inhibition of glioblastoma proliferation. Furthermore, specific depletion of PKD2 by siRNA resulted in a marked inhibition of anchorage-dependent and -independent proliferation and an accumulation of glioblastoma cells in G0/G1, accompanied by a down-regulation of cyclin D1 expression. In addition, PKD2-depleted glioblastoma cells exhibited substantially reduced tumor formation in vivo on chicken chorioallantoic membranes. These findings identify PKD2 as a novel mediator of glioblastoma cell growth in vitro and in vivo and thereby as a potential therapeutic target for this devastating disease.

• Authors: Ninel Azoitei, Alexander Kleger, Nina Schoo, Dietmar Rudolf Thal, Cornelia Brunner, Ganesh Varma Pusapati, Alina Filatova, Felicitas Genze, Peter Möller, Til Acker, Rainer Kuefer, Johan Van Lint, Heinrich Baust, Guido Adler, Thomas Seufferlein
• Journal: Neuro-oncology (Neuro Oncol) Vol. 13 Issue 7 Pg. 710-24 (Jul 2011) ISSN: 1523-5866 [Electronic] England
• PMID: 21727210 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• CCND1 protein, human
• RNA, Small Interfering
• TRPP Cation Channels
• polycystic kidney disease 2 protein
• Cyclin D1

Topics

• Animals
• Apoptosis
• Blotting, Western
• Brain (enzymology)
• Brain Neoplasms (enzymology, pathology)
• Cell Cycle
• Cell Proliferation
• Chickens
• Chorioallantoic Membrane (metabolism)
• Cyclin D1 (metabolism)
• Glioblastoma (enzymology, pathology)
• Humans
• Immunoenzyme Techniques
• RNA, Small Interfering (genetics)
• TRPP Cation Channels (antagonists & inhibitors, genetics, metabolism)