Overexpression of the death-promoting gene bax-α sensitizes human BL-41 Burkitt lymphoma cells for surface IgM-mediated apoptosis

✍ Scribed by Pamela Weinmann; Kurt Bommert; Markus Y. Mapara; Bernd Dörken; Ralf C. Bargou

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 374 KB
• Volume: 27
• Category: Article
• ISSN: 0014-2980
• DOI: 10.1002/eji.1830270947

✦ Synopsis

Abstract

Major regulators of programmed cell death, or apoptosis, are the members of the bcl‐2 gene family. Recently, we reported that surface(s) IgM triggering of the human B lymphoma cell line BL‐41 led to strong induction of bax‐α, a death‐promoting member of the bcl‐2 family, and subsequently to induction of apoptosis, suggesting a potential regulatory role of bax‐α in sIgM‐mediated cell death. In contrast, apoptosis‐resistant subclones of this cell line showed only weak bax‐α expression, which was not inducible by sIgM cross‐linking. In this study, we were able to demonstrate the functional significance of this observation. We stably transfected bax‐α into a BL‐41 subline resistant against sIgM‐mediated apoptosis. Several bax‐α overexpressing clones could be selected, which all showed enhanced sensitivity for sIgM‐mediated apoptosis. In contrast, no sensitive clone could be identified in a large number of mock controls. This clearly indicates that induction of bax‐α is a critical regulatory step, which sensitizes B cells for sIgM‐mediated apoptosis.