Glycogen synthase kinase-3β, NF-κB signaling, and tumorigenesis of human osteosarcoma.

Abstract

BACKGROUND:

Glycogen synthase kinase-3β (GSK-3β), a serine/threonine protein kinase, may function as a tumor suppressor or an oncogene, depending on the tumor type. We sought to determine the biological function of GSK-3β in osteosarcoma, a rare pediatric cancer for which the identification of new therapeutic targets is urgent.

METHODS:

We used cell viability assays, colony formation assays, and apoptosis assays to analyze the effects of altered GSK-3β expression in U2OS, MG63, SAOS2, U2OS/MTX300, and ZOS osteosarcoma cell lines. Nude mice (n = 5-8 mice per group) were injected with U2OS/MTX300, and ZOS cells to assess the role of GSK-3β in osteosarcoma growth in vivo and to evaluate the effects of inhibitors and/or anticancer drugs on tumor growth. We used an antibody array, polymerase chain reaction, western blotting, and a luciferase reporter assay to establish the effect of GSK-3β inhibition on the nuclear factor-κB (NF-κB) pathway. Immunochemistry was performed on primary tumor specimens from osteosarcoma patients (n = 74) to determine the relationship of GSK-3β activity with overall survival.

RESULTS:

Osteosarcoma cells with low levels of inactive p-Ser9-GSK-3β formed colonies in vitro and tumors in vivo more readily than cells with higher levels and cells in which GSK-3β had been silenced formed fewer colonies and smaller tumors than parental cells. Silencing or pharmacological inhibition of GSK-3β resulted in apoptosis of osteosarcoma cells. Inhibition of GSK-3β resulted in inhibition of the NF-κB pathway and reduction of NF-κB-mediated transcription. Combination treatments with GSK-3β inhibitors, NF-κB inhibitors, and chemotherapy drugs increased the effectiveness of chemotherapy drugs in vitro and in vivo. Patients whose osteosarcoma specimens had hyperactive GSK-3β, and nuclear NF-κB had a shorter median overall survival time (49.2 months) compared with patients whose tumors had inactive GSK-3β and NF-κB (109.2 months).

CONCLUSION:

GSK-3β activity may promote osteosarcoma tumor growth, and therapeutic targeting of the GSK-3β and/or NF-κB pathways may be an effective way to enhance the therapeutic activity of anticancer drugs against osteosarcoma.

• Authors: Qing-Lian Tang, Xian-Biao Xie, Jin Wang, Qiong Chen, An-Jia Han, Chang-Ye Zou, Jun-Qiang Yin, Da-Wei Liu, Yi Liang, Zhi-Qiang Zhao, Bi-Cheng Yong, Ru-Hua Zhang, Qi-Sheng Feng, Wu-Guo Deng, Xiao-Feng Zhu, Binhua P Zhou, Yi-Xin Zeng, Jing-Nan Shen, Tiebang Kang
• Journal: Journal of the National Cancer Institute (J Natl Cancer Inst) Vol. 104 Issue 10 Pg. 749-63 (May 16 2012) ISSN: 1460-2105 [Electronic] United States
• PMID: 22534782 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• NF-kappa B
• Luciferases
• GSK3B protein, human
• Glycogen Synthase Kinase 3 beta
• Gsk3b protein, mouse
• Glycogen Synthase Kinase 3
• Caspase 3

Topics

• Animals
• Apoptosis
• Blotting, Western
• Bone Neoplasms (metabolism)
• Caspase 3 (metabolism)
• Cell Line, Tumor
• Cell Survival
• Gene Silencing
• Glycogen Synthase Kinase 3 (antagonists & inhibitors, genetics, metabolism)
• Glycogen Synthase Kinase 3 beta
• Humans
• Immunohistochemistry
• Luciferases (metabolism)
• Mice
• Mice, Nude
• NF-kappa B (metabolism)
• Oncogenes
• Osteosarcoma (metabolism)
• Reverse Transcriptase Polymerase Chain Reaction
• Signal Transduction
• Transplantation, Heterologous
• Tumor Stem Cell Assay