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Abstract B264: IC261 induces cell cycle arrest and apoptosis of human cancer cells via a CK1δ/ε independent mechanism

Publication ,  Conference
Cheong, JK; Virshup, DM
Published in: Molecular Cancer Therapeutics
December 10, 2009

Casein kinase 1 delta (CK1δ) and CK1 epsilon (CK1ε) regulate Wnt/β catenin signaling and their dysregulation has been implicated in a variety of human cancers. Kinome RNAi screens and as well as targeted studies have identified CK1δ and CK1ε as prosurvival factors in a variety of cancer cell lines. While RNAi knockdown of CK1δ or CK1ε displayed only modest growth inhibition of various cell lines, the CKIδ/ε selective inhibitor 3-[2,4,6-(trimethoxyphenyl) methylidenyl]-indolin-2-one (IC261)(with an IC50 in the 20–50 µM range) has proven even more effective at selective killing of cancer cells, even at submicromolar levels. This finding has been taken as supportive evidence for the role of CKIε and CKIδ in cancer. The recent development of a selective and nanomolar CKIδ/ε inhibitor, PF670462, affords an opportunity to further explore this hypothesis. We found that PF670462 effectively blocked CK1 kinase activity and suppressed Wnt/β-catenin signaling in both HEK293 cells and HT1080 fibrosarcoma cells at submicromolar concentrations. However, consistent with the results of siRNA knockdown of CK1ε, PF670462 failed to induce cancer cell death at these concentrations. In contrast, we found that while 100 nM IC261 did not inhibit of CK1ε activity nor block Wnt/ catenin signaling in vivo, it resulted in the rapid induction of G2/M arrest of cell cycle and apoptosis in human cancer, but not non-transformed, cells. Taken together, inactivation of CK1δ/ε and subsequent block of Wnt/β catenin signaling may not be sufficient to inhibit cancer cell survival. Furthermore, IC261 potently regulates additional cancer cell targets at concentrations much lower than that required for CK1 inhibition and these novel unknown targets appear to be important for the maintenance of human cancer cell survival. Identification of the IC261 targets may provide insights into the mechanism of selective cancer cell toxicity.Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B264.

Duke Scholars

Published In

Molecular Cancer Therapeutics

DOI

EISSN

1538-8514

ISSN

1535-7163

Publication Date

December 10, 2009

Volume

8

Issue

12_Supplement

Start / End Page

B264 / B264

Publisher

American Association for Cancer Research (AACR)

Related Subject Headings

  • Oncology & Carcinogenesis
  • 3211 Oncology and carcinogenesis
  • 3101 Biochemistry and cell biology
  • 1115 Pharmacology and Pharmaceutical Sciences
  • 1112 Oncology and Carcinogenesis
 

Citation

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Cheong, J. K., & Virshup, D. M. (2009). Abstract B264: IC261 induces cell cycle arrest and apoptosis of human cancer cells via a CK1δ/ε independent mechanism. In Molecular Cancer Therapeutics (Vol. 8, pp. B264–B264). American Association for Cancer Research (AACR). https://doi.org/10.1158/1535-7163.targ-09-b264
Cheong, Jit Kong, and David M. Virshup. “Abstract B264: IC261 induces cell cycle arrest and apoptosis of human cancer cells via a CK1δ/ε independent mechanism.” In Molecular Cancer Therapeutics, 8:B264–B264. American Association for Cancer Research (AACR), 2009. https://doi.org/10.1158/1535-7163.targ-09-b264.
Cheong JK, Virshup DM. Abstract B264: IC261 induces cell cycle arrest and apoptosis of human cancer cells via a CK1δ/ε independent mechanism. In: Molecular Cancer Therapeutics. American Association for Cancer Research (AACR); 2009. p. B264–B264.
Cheong, Jit Kong, and David M. Virshup. “Abstract B264: IC261 induces cell cycle arrest and apoptosis of human cancer cells via a CK1δ/ε independent mechanism.” Molecular Cancer Therapeutics, vol. 8, no. 12_Supplement, American Association for Cancer Research (AACR), 2009, pp. B264–B264. Crossref, doi:10.1158/1535-7163.targ-09-b264.
Cheong JK, Virshup DM. Abstract B264: IC261 induces cell cycle arrest and apoptosis of human cancer cells via a CK1δ/ε independent mechanism. Molecular Cancer Therapeutics. American Association for Cancer Research (AACR); 2009. p. B264–B264.

Published In

Molecular Cancer Therapeutics

DOI

EISSN

1538-8514

ISSN

1535-7163

Publication Date

December 10, 2009

Volume

8

Issue

12_Supplement

Start / End Page

B264 / B264

Publisher

American Association for Cancer Research (AACR)

Related Subject Headings

  • Oncology & Carcinogenesis
  • 3211 Oncology and carcinogenesis
  • 3101 Biochemistry and cell biology
  • 1115 Pharmacology and Pharmaceutical Sciences
  • 1112 Oncology and Carcinogenesis