Logo image
Deletion of Rb1 induces both hyperproliferation and cell death in murine germinal center B cells
Journal article   Open access   Peer reviewed

Deletion of Rb1 induces both hyperproliferation and cell death in murine germinal center B cells

Zhiwen He, Julie O'Neal, William C Wilson, Nitin Mahajan, Jun Luo, Yinan Wang, Mack Y Su, Lan Lu, James B Skeath, Deepta Bhattacharya, …
Experimental hematology, Vol.44(3), pp.161-165.e4
03/2016
DOI: 10.1016/j.exphem.2015.11.006
PMCID: PMC4789175
PMID: 26607597
url
https://doi.org/10.1016/j.exphem.2015.11.006View
Published (Version of record) Open Access

Abstract

The retinoblastoma gene (RB1) has been implicated as a tumor suppressor in multiple myeloma (MM), yet its role remains unclear because in the majority of cases with 13q14 deletions, un-mutated RB1 remains expressed from the retained allele. To explore the role of Rb1 in MM, we examined the functional consequences of single- and double-copy Rb1 loss in germinal center B cells, the cells of origin of MM. We generated mice without Rb1 function in germinal center B cells by crossing Rb1(Flox/Flox) with C-γ-1-Cre (Cγ1) mice expressing the Cre recombinase in class-switched B cells in a p107(-/-) background to prevent p107 from compensating for Rb1 loss (Cγ1-Rb1(F/F)-p107(-/-)). All mice developed normally, but B cells with two copies of Rb1 deleted (Cγ1-Rb1(F/F)-p107(-/-)) exhibited increased proliferation and cell death compared with Cγ1-Rb1(+/+)-p107(-/-) controls ex vivo. In vivo, Cγ1-Rb1(F/F)-p107(-/-) mice had a lower percentage of splenic B220+ cells and reduced numbers of bone marrow antigen-specific secreting cells compared with control mice. Our data indicate that Rb1 loss induces both cell proliferation and death in germinal center B cells. Because no B-cell malignancies developed after 1 year of observation, our data also suggest that Rb1 loss is not sufficient to transform post-germinal center B cells and that additional, specific mutations are likely required to cooperate with Rb1 loss to induce malignant transformation.
Animals B-Lymphocytes - metabolism B-Lymphocytes - pathology Cell Death Cell Proliferation Cell Transformation, Neoplastic - genetics Cell Transformation, Neoplastic - metabolism Cell Transformation, Neoplastic - pathology Germinal Center - metabolism Germinal Center - pathology Mice Mice, Knockout Mutation Retinoblastoma Protein - deficiency

Details

Metrics

Logo image