Ectopic expression of a combination of 5 genes detects high risk forms of T-cell acute lymphoblastic leukemia.

BACKGROUND: T cell acute lymphoblastic leukemia (T-ALL) defines a group of hematological malignancies with heterogeneous aggressiveness and highly variable outcome, making therapeutic decisions a challenging task. We tried to discover new predictive model for T-ALL before treatment by using a specific pipeline designed to discover aberrantly active gene. RESULTS: The expression of 18 genes was significantly associated with shorter survival, including ACTRT2, GOT1L1, SPATA45, TOPAZ1 and ZPBP (5-GEC), which were used as a basis to design a prognostic classifier for T-ALL patients. The molecular characterization of the 5-GEC positive T-ALL unveiled specific characteristics inherent to the most aggressive T leukemic cells, including a drastic shut-down of genes located on the mitochondrial genome and an upregulation of histone genes, the latter characterizing high risk forms in adult patients. These cases fail to respond to the induction treatment, since 5-GEC either predicted positive minimal residual disease (MRD) or a short-term relapse in MRD negative patients. CONCLUSION: Overall, our investigations led to the discovery of a homogenous group of leukemic cells with profound alterations of their biology. It also resulted in an accurate predictive tool that could significantly improve the management of T-ALL patients.

2-Bromopalmitate targets retinoic acid receptor alpha and overcomes all-trans retinoic acid resistance of acute promyelocytic leukemia.

Fatty acid oxidation dependency of leukemia cells has been documented in recent studies. Pharmacologic inhibition of fatty acid oxidation, thereby, displays significant effects in suppressing leukemia. 2-Bromopalmitate, a palmitate analogue, was initially identified as an inhibitor of fatty acid oxidation, and recently recognized as an inhibitor of protein palmitoylation. However, the effects of 2-Bromopalmitate on leukemia and its cellular targets remain obscure. Herein, we discover in cultured cell lines, a transplantable mouse model, and primary blasts that 2-Bromopalmitate presents synergistic differentiation induction with all-trans retinoic acid in acute promyelocytic leukemia. Moreover, 2-Bromopalmitate overcomes all-trans retinoic acid resistance in all-trans retinoic acid-resistant cells and leukemic mice. Mechanistically, 2-Bromopalmitate covalently binds at cysteine 105 and cysteine 174 of retinoic acid receptor alpha (RARα) and stabilizes RARα protein in the presence of all-trans retinoic acid which is known to induce RARα degradation, leading to enhanced transcription of RARα-target genes. Mutation of both cysteines largely abrogates the synergistic effect of 2-Bromopalmitate on all-trans retinoic acid-induced differentiation, demonstrating that 2-Bromopalmitate promotes all-trans retinoic acid-induced differentiation through binding RARα. All-trans retinoic acid-based regimens including arsenic trioxide or chemotherapy, as preferred therapy for acute promyelocytic leukemia, induce adverse events and irreversible resistance. We expect that combining all-trans retinoic acid with 2-Bromopalmitate would be a promising therapeutic strategy for acute promyelocytic leukemia, especially for overcoming all-trans retinoic acid resistance of relapsed acute promyelocytic leukemia patients.

Arsenic trioxide at conventional dosage does not aggravate hemorrhage in the first-line treatment of adult acute promyelocytic leukemia.

OBJECTIVES: The arsenic trioxide (ATO) plus all-trans retinoic acid (ATRA) therapy has demonstrated a tremendous success in the first-line treatment of acute promyelocytic leukemia (APL). Actually, early death (ED) is currently thought as a major challenge in APL. ATO has been reported to inhibit platelet function in vitro, and whether it increases the ED rate by exacerbating the hemorrhagic symptoms remains to be investigated. METHODS: Effects of ATO on platelet aggregation and adhesion were evaluated in vitro and in thirty-two complete remission (CR) and four newly diagnosed APL patients. Furthermore, concentrations of plasma total arsenic were monitored in APL patients via ICP-MS. RESULTS: The inhibition of platelet function, either aggregation or adhesion, did occur in vitro when the concentration of ATO reached 2 µmol/L. However, in CR APL patients receiving ATO with normal platelet count, the platelets responded normally when being activated and so did those in the newly diagnosed patients with thrombocytopenia. Our data further showed that the conventional dosage of ATO reached a plasma concentration substantially below the required concentration to inhibit platelets. CONCLUSIONS: In the first-line treatment of APL, the use of ATO is safe and effective and does not compromise the hemostatic potential that may eventually increase ED rate.