C/EBPα Induces Highly Efficient Macrophage Transdifferentiation of B Lymphoma and Leukemia Cell Lines and Impairs Their Tumorigenicity

Earlier work demonstrated that the transcription factor C/EBP alpha can convert immature and mature murine B lineage cells into functional macrophages. Testing >20 human lymphoma and leukemia B cell lines, we found that most can be transdifferentiated at least partially intomacrophage-like cells, provided that C/EBP alpha is expressed at sufficiently high levels. A tamoxifen-inducible subclone of the Seraphina Burkitt lymphoma line, expressing C/EBP alpha ER, could be efficiently converted into phagocytic and quiescent cells with a transcriptome resembling normal macrophages. The converted cells retained their phenotype even when C/EBP alpha was inactivated, a hallmark of cell reprogramming. Interestingly, C/EBP alpha induction also impaired the cells' tumorigenicity. Likewise, C/EBP alpha efficiently converted a lymphoblastic leukemia B cell line into macrophage-like cells, again dramatically impairing their tumorigenicity. Our experiments show that human cancer cells can be induced by C/EBP alpha to transdifferentiate into seemingly normal cells at high frequencies and provide a proof of principle for a potential new therapeutic strategy for treating B cell malignancies.