Reduced Erg Dosage Impairs Survival of Hematopoietic Stem and Progenitor Cells.

ERG, an ETS family transcription factor frequently overexpressed in human leukemia, has been implicated as a key regulator of hematopoietic stem cells. However, how ERG controls normal hematopoiesis, particularly at the stem and progenitor cell level, and how it contributes to leukemogenesis remain incompletely understood. Using homologous recombination, we generated an Erg knockdown allele (Erg ) in which Erg expression can be conditionally restored by Cre recombinase.

ETV1 directs androgen metabolism and confers aggressive prostate cancer in targeted mice and patients.

Distinguishing aggressive from indolent disease and developing effective therapy for advanced disease are the major challenges in prostate cancer research. Chromosomal rearrangements involving ETS transcription factors, such as ERG and ETV1, occur frequently in prostate cancer. How they contribute to tumorigenesis and whether they play similar or distinct in vivo roles remain elusive.

Developmental stage-specific interplay of GATA1 and IGF signaling in fetal megakaryopoiesis and leukemogenesis.

Oncogene-mediated transformation of hematopoietic cells has been studied extensively, but little is known about the molecular basis for restriction of oncogenes to certain target cells and differential cellular context-specific requirements for oncogenic transformation between infant and adult leukemias. Understanding cell type-specific interplay of signaling pathways and oncogenes is essential for developing targeted cancer therapies. Here, we address the vexing issue of how developmental restriction is achieved in Down syndrome acute megakaryoblastic leukemia (DS-AMKL), characterized by the triad of fetal origin, mutated GATA1 (GATA1s), and trisomy 21.

miR-125b-2 is a potential oncomiR on human chromosome 21 in megakaryoblastic leukemia.

Children with trisomy 21/Down syndrome (DS) are at high risk to develop acute megakaryoblastic leukemia (DS-AMKL) and the related transient leukemia (DS-TL). The factors on human chromosome 21 (Hsa21) that confer this predisposing effect, especially in synergy with consistently mutated transcription factor GATA1 (GATA1s), remain poorly understood. Here, we investigated the role of Hsa21-encoded miR-125b-2, a microRNA (miRNA) overexpressed in DS-AMKL/TL, in hematopoiesis and leukemogenesis.

ETV6-NTRK3 fusion oncogene initiates breast cancer from committed mammary progenitors via activation of AP1 complex.

To better understand the cellular origin of breast cancer, we developed a mouse model that recapitulates expression of the ETV6-NTRK3 (EN) fusion oncoprotein, the product of the t(12;15)(p13;q25) translocation characteristic of human secretory breast carcinoma. Activation of EN expression in mammary tissues by Wap-Cre leads to fully penetrant, multifocal malignant breast cancer with short latency. We provide genetic evidence that, in nulliparous Wap-Cre;EN females, committed alveolar bipotent or CD61(+) luminal progenitors are targets of tumorigenesis.

Developmental stage-selective effect of somatically mutated leukemogenic transcription factor GATA1.

Acquired mutations in the hematopoietic transcription factor GATA binding protein-1 (GATA1) are found in megakaryoblasts from nearly all individuals with Down syndrome with transient myeloproliferative disorder (TMD, also called transient leukemia) and the related acute megakaryoblastic leukemia (DS-AMKL, also called DS-AML M7). These mutations lead to production of a variant GATA1 protein (GATA1s) that is truncated at its N terminus. To understand the biological properties of GATA1s and its relation to DS-AMKL and TMD, we used gene targeting to generate Gata1 alleles that express GATA1s in mice.