Molecular and Cellular Biochemistry

, Volume 316, Issue 1, pp 91–97

Impact of protein kinase CK2 on inhibitor of apoptosis proteins in prostate cancer cells

  • Guixia Wang
  • Kashif A. Ahmad
  • Nathan H. Harris
  • Khalil Ahmed
Article

DOI: 10.1007/s11010-008-9810-9

Cite this article as:
Wang, G., Ahmad, K.A., Harris, N.H. et al. Mol Cell Biochem (2008) 316: 91. doi:10.1007/s11010-008-9810-9

Abstract

We have previously demonstrated that protein kinase CK2 is a potent suppressor of apoptosis in cells subjected to diverse mediators of apoptosis. The process of apoptosis involves a complex series of molecules localized in various cellular compartments. Among the various proteins that modulate apoptotic activity are inhibitors of apoptosis proteins (IAPs) which are elevated in cancers and have been proposed to block caspase activity. We have examined the impact of CK2 signal on these proteins in prostate cancer cells. Cellular IAPs demonstrate distinct localization and responsiveness to altered CK2 expression or activity in the cytoplasmic and nuclear matrix fractions. Modulation of cellular CK2 by various approaches impacts on cellular IAPs such that inhibition or downregulation of CK2 results in reduction in these proteins. Further, IAPs are also reduced when cells are treated with sub-optimal concentrations of chemical inhibitors of CK2 combined with low or sub-optimal levels of apoptosis-inducing agents (such as etoposide) suggesting that downregulation of CK2 sensitizes cells to induction of apoptosis which may be related to attenuation of IAPs. Decreased IAP protein levels in response to apoptotic agents such as TNFα or TRAIL were potently blocked upon forced overexpression of CK2 in cells. Together, our results suggest that one of the modes of CK2-mediated modulation of apoptotic activity is via its impact on cellular IAPs.

Key words

Protein kinase CK2Casein kinase 2ApoptosisProstate cancerInhibitor of apoptosis proteinsIAPSurvivin

Abbreviations

CK2

Acronym for the former name casein kinase II

CK2α

CK2 catalytic subunit α

CK2β

CK2 regulatory subunit β

IAPs

Inhibitor of apoptosis proteins such as cIAP1, cIAP2, XIAP, survivin

TBB

4,5,6,7-Tetrabromobenzotriazole

MNA

1,8-Dihydroxy-4-nitro-anthracene-9,10-dione

TRAIL

Tumor necrosis factor-related apoptosis inducing ligand

TNFα

Tumor necrosis factor α

FBS

Fetal bovine serum

Copyright information

© Springer Science+Business Media, LLC. 2008

Authors and Affiliations

  • Guixia Wang
    • 1
    • 2
    • 3
  • Kashif A. Ahmad
    • 1
    • 2
    • 3
    • 4
  • Nathan H. Harris
    • 1
    • 2
    • 3
  • Khalil Ahmed
    • 1
    • 2
    • 3
  1. 1.Cellular and Molecular Biochemistry Research Laboratory (151), Minneapolis Veterans Affairs Medical CenterUniversity of MinnesotaMinneapolisUSA
  2. 2.Department of Laboratory Medicine and PathologyUniversity of MinnesotaMinneapolisUSA
  3. 3.Masonic Cancer CenterUniversity of MinnesotaMinneapolisUSA
  4. 4.Northwestern Health Sciences UniversityBloomingtonUSA