Altered Expression of Genes in Signaling Pathways Regulating Proliferation of Hematopoietic Stem and Progenitor Cells in Mice with Subchronic Benzene Exposure

Abstract

Leukemias and hematopoietic disorders induced by benzene may arise from the toxicity of benzene to hematopoietic stem or progenitor cells (HS/PCs). Since there is a latency period between initial benzene exposure and the development of leukemia, subsequent impact of benzene on HS/PCs are crucial for a deeper understanding of the carcinogenicity and hematotoxicity in post-exposure stage. This study aims to explore the effects of benzene on HS/PCs and gene-expression in Wnt, Notch and Hh signaling pathways in post-exposure stage. The C3H/He mice were injected subcutaneously with benzene (0, 150, 300 mg/kg/day) for three months and were monitored for another 10 months post-exposure. The body weights were monitored, the relative organ weights, blood parameters and bone marrow smears were examined. Frequency of lineage- sca-1+ c-kit+ (LSK) cells, capability of colony forming and expression of genes in Wnt, Notch and Hedghog (Hh) signaling pathways were also analyzed. The colony formation of the progenitor cells for BFU-E, CFU-GEMM and CFU-GM was significantly decreased with increasing benzene exposure relative to controls, while no significant difference was observed in colonies for CFU-G and CFU-M. The mRNA level of cyclin D1 was increased and Notch1 and p53 were decreased in LSK cells in mice exposed to benzene but with no statistical significance. These results suggest that subsequent toxic effects of benzene on LSK cells and gene expression in Wnt, Notch and Hh signaling pathways persist in post-exposure stage and may play roles in benzene-induced hematotoxicity.

Epigenetic Effects of Benzene in Hematologic Neoplasms: The Altered Gene Expression

“…Benzene and its metabolites cause harmfulness toward hemopoietic stem cells (HSCs), comprising short- and long-lasting injury to HSCs, and determine negative effects on the BM hematopoietic milieu [ 60 ]. Benzene contact decreases not only the rate and amount of BM HSCs in animals, but also reduces colony generation, which was also reported in in vivo analyses [ 61 , 62 ].…”

Benzene Exposure Alters Expression of Enzymes Involved in Fatty Acid β-Oxidation in Male C3H/He Mice

“…The cellularity changes in specific lineages after benzene exposure were not investigated here. In our previous study [22,23], the dose of benzene used could also cause significantly decreased frequency of HSCs (Lin − C-kit + Sca-1 + ), increased ratio of original granulocyte and promyelocytes in bone marrow, and reduced burst-forming unit-erythroid (BFU-E), committed progenitors granulocytes-erythroid-monocyte-megakaryocyte (CFU-GEMM), and granulocyte- macrophages (CFU-GM) progenitors [23]. …”

Clastogenicity and Aneugenicity of 1,4-Benzoquinone in Different Lineages of Mouse Hematopoietic Stem/Progenitor Cells

“…The mechanism of benzene-induced hematological diseases and malignancies is still not fully understood. Many previous studies demonstrated that the main target of benzene-induced toxicity is HSPCs [ 19 , 29 , 30 , 31 , 32 ]. Few previous epidemiology studies showed the association between human exposure on benzene and CA such as translocation and aneuploidy [ 3 , 5 , 33 ].…”