Differential effects of BAFF on B cell precursor acute lymphoblastic leukemia and Burkitt lymphoma
B cell-activating factor belonging to the tumor necrosis factor superfamily (BAFF) is a crucial factor for B cell development and is involved in the survival of malignant B cells, but its effect on B cell precursors (BCPs) remains unclear. We investigated BCP acute lymphoblastic leukemia (-ALL) cells for BAFF receptor (-R) expression and compared the effect of BAFF on BCP-ALL cells and Burkitt lymphoma (BL) cells. Expression of BAFF-R was detected in some cell lines and some clinical specimens of both BL and BCP-ALL. BAFF acted on both BL and BCP-ALL cells and promoted proliferation by both. BAFF also inhibited apoptosis by BL cells induced by cross-linking of cell surface molecules and anticancer drugs, but failed to inhibit apoptosis by BCP-ALL cells. BAFF induced prompt and obvious activation of the NF-κB signaling pathway in BL cells, but only weak and delayed activation of the pathway in BCP-ALL cells. The results of this study indicate that some BCP-ALL cells and some BL cells express BAFF-R, but that the effects of BAFF on BCP-ALL cells are different from its effects on mature B cell malignancies.
KeywordsBAFF B cell precursor ALL Burkitt lymphoma Apoptosis
We thank Dr. K. J. Mori and Dr. Y. Matsuo for the gift of murine BM stromal cell line MS-5 and BL/BCP-ALL cell lines, respectively. We also thank Ms. H. Kiyokawa for her assistance in preparing the manuscript. This work was supported by a grant from the Japan Health Sciences Foundation for Research on Publicly Essential Drugs and Medical Devices (KHA1004), Health and Labour Sciences Research Grants (the 3rd-term comprehensive 10-year-strategy for cancer control H19-010), and a Grant for Child Health and Development from the Ministry of Health, Labour and Welfare of Japan.
Conflict of interest statement
We have no financial relationships or conflicts of interest related to this manuscript.