Double targeting of Survivin and XIAP radiosensitizes 3D grown human colorectal tumor cells and decreases migration.

Abstract

BACKGROUND AND PURPOSE:

In the present study, we aimed to investigate the effect of single and double knockdown of the inhibitor of apoptosis proteins (IAP) Survivin and X-linked IAP (XIAP) on three-dimensional (3D) clonogenic survival, migration capacity and underlying signaling pathways.

MATERIALS AND METHODS:

Colorectal cancer cell lines (HCT-15, SW48, SW480, SW620) were subjected to siRNA-mediated single or Survivin/XIAP double knockdown followed by 3D colony forming assays, cell cycle analysis, Caspase activity assays, migration assays, matrigel transmigration assays and Western blotting (Survivin, XIAP, Focal adhesion kinase (FAK), p-FAK Y397, Akt1, p-Akt1 S473, Extracellular signal-regulated kinase (ERK1/2), p-ERK1/2 T202/Y204, Glycogen synthase kinase (GSK)3β, p-GSK3β S9, nuclear factor (NF)-κB p65).

RESULTS:

While basal cell survival was altered cell line-dependently, Survivin or XIAP single and Survivin/XIAP double knockdown enhanced cellular radiosensitivity of all tested cancer cell lines grown in 3D. Particularly double knockdown conditions revealed accumulation of cells in G2/M, increased subG1 fraction, elevated Caspase 3/7 activity, and reduced migration. Intracellular signaling showed dephosphorylation of FAK and Akt1 upon Survivin and/or Survivin/XIAP silencing.

CONCLUSIONS:

Our results strengthen the notion of Survivin and XIAP to act as radiation resistance factors and further indicate that these apoptosis-regulating proteins are also functioning in cell cycling and cell migration.

• Authors: Stephanie Hehlgans, Chrysi Petraki, Sebastian Reichert, Nils Cordes, Claus Rödel, Franz Rödel
• Journal: Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology (Radiother Oncol) Vol. 108 Issue 1 Pg. 32-9 (Jul 2013) ISSN: 1879-0887 [Electronic] Ireland
• PMID: 23830189 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Chemical References

• BIRC5 protein, human
• Inhibitor of Apoptosis Proteins
• Survivin
• X-Linked Inhibitor of Apoptosis Protein
• Focal Adhesion Protein-Tyrosine Kinases
• Proto-Oncogene Proteins c-akt

Topics

• Cell Cycle
• Cell Line, Tumor
• Cell Movement
• Colorectal Neoplasms (pathology, radiotherapy)
• Focal Adhesion Protein-Tyrosine Kinases (metabolism)
• Humans
• Inhibitor of Apoptosis Proteins (antagonists & inhibitors, physiology)
• Phosphorylation
• Proto-Oncogene Proteins c-akt (metabolism)
• Radiation Tolerance
• Survivin
• X-Linked Inhibitor of Apoptosis Protein (antagonists & inhibitors, physiology)