Benzene metabolite hydroquinone enhances self-renewal and proliferation of preleukemic cells through the Ppar-γ pathway.

Benzene is a known hematotoxic and leukemogenic chemical. Exposure to benzene cause inhibition of hematopoietic cells. However, the mechanism of how the hematopoietic cells inhibited by benzene undergo malignant proliferation is unknown. The cells carrying leukemia-associated fusion genes are present in healthy individuals and predispose the carriers to the development of leukemia. To identify the effects of benzene on hematopoietic cells, preleukemic bone marrow (PBM) cells derived from transgenic mice carrying the Mll-Af9 fusion gene were treated with benzene metabolite hydroquinone in serial replating of colony-forming unit (CFU) assay. RNA sequencing was further employed to identify the potential key genes that contributed to benzene-initiated self-renewal and proliferation. We found that hydroquinone induced a significant increase in colony formation in PBM cells. Peroxisome proliferator-activated receptor gamma (Ppar-γ) pathway, which plays a critical role in carcinogenesis in multiple tumors, was significantly activated after hydroquinone treatment. Notably, the increased numbers of the CFUs and total PBM cells induced by hydroquinone were significantly reduced by a specific Ppar-γ inhibitor (GW9662). These findings indicated that hydroquinone can enhance self-renewal and proliferation of preleukemic cells by activating the Ppar-γ pathway. Our results provide insight into the missing link between premalignant status and development of benzene-induced leukemia, which can be intervened and prevented.