Chimeric oncoprotein E2a-Pbx1 induces apoptosis of hematopoietic cells by a p53-independent mechanism that is suppressed by Bcl-2 (original) (raw)

Oncogene volume 14, pages 2917–2926 (1997)Cite this article

Abstract

The chimeric oncoprotein E2a-Pbx1 results from fusion of the E2A and PBX1 genes following t(1;19) chromosomal translocations in B cell precursor acute leukemias. Experimentally B cell progenitors do not tolerate constitutive expression of E2a-Pbx1 which contrasts with transformation of several other cell types following its stable expression both in vitro and in vivo. To further investigate the effects of E2a-Pbx1 on the B cell progenitors, we conditionally expressed E2a-Pbx1 under control of a metal response element in hematopoietic precursor cell lines in vitro. Inducible expression of E2a-Pbx1 resulted in cell death with the morphologic and molecular features of apoptosis. A structure-function analysis demonstrated that induction of apoptosis was not a dominant-negative effect of the E2a moiety but, rather, required the DNA-binding homeodomain of Pbx1. E2a-Pbx1-induced apoptosis proceeded through a BCL2-responsive checkpoint eventuating in PARP inactivation but did require p53. Constitutive expression of E2a-Pbx1 did not induce apoptosis or continued cycling of Rat-1 fibroblasts in low serum conditions. These studies demonstrate that E2a-Pbx1 initiates programmed cell death of hematopoietic precursers by a mechanism that requires its chimeric transcriptional properties, but, unlike other nuclear oncoproteins, is independent of p53.

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Authors and Affiliations

  1. Department of Pathology, Laboratory of Experimental Oncology, Stanford University Medical Center, Stanford, 94305, California, USA
    Kevin S Smith, Yakop Jacobs, Ching-Pin Chang & Michael L Cleary

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  1. Kevin S Smith
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  2. Yakop Jacobs
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  3. Ching-Pin Chang
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  4. Michael L Cleary
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Smith, K., Jacobs, Y., Chang, CP. et al. Chimeric oncoprotein E2a-Pbx1 induces apoptosis of hematopoietic cells by a p53-independent mechanism that is suppressed by Bcl-2.Oncogene 14, 2917–2926 (1997). https://doi.org/10.1038/sj.onc.1201249

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