Targeting 14-3-3 protein, difopein induces apoptosis of human glioma cells and suppresses tumor growth in mice.

Abstract

14-3-3 protein has emerged as critical regulators of diverse cellular responses. Previous studies found that strong 14-3-3 protein expression was observed and associated with tumor genesis and progression in glioma. Here, we further elucidated the role of 14-3-3 protein in apoptosis of human glioma U251 and U87 cells by global inhibition of 14-3-3 functions with a general 14-3-3 antagonist, difopein. In vitro, morphological observation and DNA laddering assay showed that difopein-treated glioma cells displayed outstanding apoptosis characteristics, such as nuclear fragmentation, appearance of membrane-enclosed apoptotic bodies and DNA laddering fragment. Moreover, flow cytometric detection of phosphatidylserine externalization indicated that difopein-induced apoptosis occurred in a time-dependent manner. Interestingly, inhibiting 14-3-3 with small interfere RNA also induce apoptosis of human glioma U251 cells. Furthermore, RT-PCR and western blot assay further substantiated that difopein had strong effects to induce glioma cell apoptosis through down-regulating Bcl-2, up-regulating Bax and activating caspase-9 and caspase-3. In vivo, retroviral vector was constructed and retroviral-mediated transfer of difopein to glioma was implanted in nude mice. Difopein effectively hindered proliferation and triggered apoptosis of tumor cells implanted into nude mice. This work not only reveals a critical role of 14-3-3 in apoptosis suppression in glioma cells, but also identifies and validates 14-3-3 as a potential molecular target for anticancer therapeutic development.

• Authors: Weidong Cao, Xiaoliang Yang, Jie Zhou, Zenghui Teng, Lei Cao, Xiang Zhang, Zhou Fei
• Journal: Apoptosis : an international journal on programmed cell death (Apoptosis) Vol. 15 Issue 2 Pg. 230-41 (Feb 2010) ISSN: 1573-675X [Electronic] Netherlands
• PMID: 20033782 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 14-3-3 Proteins
• Proteins
• Proto-Oncogene Proteins c-bcl-2
• RNA, Messenger
• RNA, Small Interfering
• difopein

Topics

• 14-3-3 Proteins (antagonists & inhibitors, metabolism)
• Animals
• Apoptosis (drug effects)
• Cell Cycle (drug effects)
• Cell Line, Tumor
• Cell Proliferation (drug effects)
• DNA Fragmentation (drug effects)
• Flow Cytometry
• Fluorescence
• Gene Expression Regulation, Neoplastic (drug effects)
• Gene Transfer Techniques
• Glioma (pathology, ultrastructure)
• Humans
• Mice
• Proteins (pharmacology)
• Proto-Oncogene Proteins c-bcl-2 (metabolism)
• RNA, Messenger (genetics, metabolism)
• RNA, Small Interfering (metabolism)
• Retroviridae (genetics)
• Xenograft Model Antitumor Assays