Hepatic iron overload, a possible consequence of treatment with imatinib mesylate: a case report

Imatinib, a tyrosine kinase inhibitor has revolutionized the therapy of Philadelphia chromosome positive chronic myeloid leukemia. Side effects of imatinib include grade 1-4 hepatotoxicity in a subset of patients. We report the case of a 46-year-old male with chronic myeloid leukemia, who developed hepatic hemosiderosis during treatment with imatinib. After ruling out the established congenital and acquired causes of hepatic hemosiderosis, we attribute this to a possible side effect of imatinib therapy. This condition was successfully treated with periodic phlebotomy thus precluding discontinuation of imatinib. To our knowledge, this is the first report of hepatic hemosiderosis most likely consequent to imatinib therapy

E2F-8: an E2F family member with a similar organization of DNA-binding domains to E2F-7

E2F is a family of transcription factors implicated in cell cycle control. To understand the role of E2F in controlling cell cycle progression, it is necessary to clarify the breadth of the E2F family. To date, seven E2F subunits have been identified. We report here the characterization of a new E2F subunit, E2F-8, which resembles the organization of E2F-7 in the presence of two separate DNA-binding domains, the integrity of which is required for E2F-8 to bind to DNA. Furthermore, like E2F-7, we find that E2F-8 can repress transcription and delay cell cycle progression. The similarities between E2F-7 and E2F-8 define a new subgroup of the E2F family, and further imply that E2F-7 and E2F-8 may act through overlapping mechanisms in mediating cell cycle control

E2f1, E2f2, and E2f3 Control E2F Target Expression and Cellular Proliferation via a p53-Dependent Negative Feedback Loop

E2F-mediated control of gene expression is believed to have an essential role in the control of cellular proliferation. Using a conditional gene-targeting approach, we show that the targeted disruption of the entire E2F activator subclass composed of E2f1, E2f2, and E2f3 in mouse embryonic fibroblasts leads to the activation of p53 and the induction of p53 target genes, including p21(CIP1). Consequently, cyclin-dependent kinase activity and retinoblastoma (Rb) phosphorylation are dramatically inhibited, leading to Rb/E2F-mediated repression of E2F target gene expression and a severe block in cellular proliferation. Inactivation of p53 in E2f1-, E2f2-, and E2f3-deficient cells, either by spontaneous mutation or by conditional gene ablation, prevented the induction of p21(CIP1) and many other p53 target genes. As a result, cyclin-dependent kinase activity, Rb phosphorylation, and E2F target gene expression were restored to nearly normal levels, rendering cells responsive to normal growth signals. These findings suggest that a critical function of the E2F1, E2F2, and E2F3 activators is in the control of a p53-dependent axis that indirectly regulates E2F-mediated transcriptional repression and cellular proliferation