The combination of Nutlin-3 and Tanshinone IIA promotes synergistic cytotoxicity in acute leukemic cells expressing wild-type p53 by co-regulating MDM2-P53 and the AKT/mTOR pathway.

P53 dysfunction has been associated with various malignant tumors, including acute leukemia. The overexpression of mouse double minute 2 (MDM2) causes the inactivation of p53 in acute leukemia. MDM2 inhibitors that activate p53 and induce apoptosis are currently being developed for potential treatment of acute leukemia. However, MDM2 inhibitors alone have limited efficacy in acute leukemia therapeutics. Combining other drugs to enhance the efficacy of MDM2 inhibitors is the thus considered as a potential treatment scheme. Here, we report that the combination of Nutlin-3 and Tanshinone IIA synergistically induces cytotoxicity, cell cycle arrest, apoptosis, and autophagic cell death, thereby imparting anti-leukemia effect in an acute leukemia cell line with wild-type p53 by effectively activating p53, inhibiting the AKT/mTOR pathway, and activating the RAF/MEK pathway. Using primary samples from acute leukemia patients, we show that the combination of Nutlin-3 plus Tanshinone IIA synergistically induces cytotoxicity by activating p53 and inhibiting the AKT/mTOR pathway. This specific combination of Nutlin-3 and Tanshinone IIA is also effective in preventing the recurrence of refractory leukemia, such as Ph+ ALL with the ABL kinase T315I mutation and AML with the FLT3-ITD mutation. Taken together, the results of this study demonstrate that the Nutlin-3 plus Tanshinone IIA combination exerts synergistic anti-leukemia effects by regulating the p53 and AKT/mTOR pathways, although further investigation is warranted. Small-molecule MDM2 antagonists plus Tanshinone IIA may thus be a promising strategy for the treatment of acute leukemia.

Nutlin-3 plus tanshinone IIA exhibits synergetic anti-leukemia effect with imatinib by reactivating p53 and inhibiting the AKT/mTOR pathway in Ph+ ALL.

Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) is triggered by BCR/ABL kinase. Recent efforts focused on the development of more potent tyrosine kinase inhibitors (TKIs) that also inhibit mutant tyrosine kinases such as nilotinib and dasatinib. Although major advances in the treatment of this aggressive disease with potent inhibitors of the BCR/ABL kinases, patients in remission frequently relapse due to drug resistance possibly mediated, at least in part, by compensatory activation of growth-signaling pathways and protective feedback signaling of leukemia cells in response to TKI treatment. Continuous activation of AKT/mTOR signaling and inactivation of p53 pathway were two mechanisms of TKI resistance. Here, we reported that nutlin-3 plus tanshinone IIA significantly potentiated the cytotoxic and apoptotic induction effects of imatinib by down-regulation of the AKT/mTOR pathway and reactivating the p53 pathway deeply in Ph+ ALL cell line. In primary samples from Ph+ ALL patients, nutlin-3 plus tanshinone IIA also exhibited synergetic cytotoxic effects with imatinib. Of note, three samples from Ph+ ALL patients harboring T315I mutation also showed sensitivity to the combined treatment of imatinib, nutlin-3 plus tanshinone IIA. In Ph+ ALL mouse models, imatinib combined with nutlin-3 plus tanshinone IIA also exhibited synergetic effects on reduction in leukemia burden. These results demonstrated that nutlin-3 plus tanshinone IIA combined TKI might be a promising treatment strategy for Ph+ ALL patients.

[Comparing BFA with BuCyA as a myeloablative conditioning regimen for allogeneic stem cell transplantation in acute leukemias].

OBJECTIVE: To compare BFA (busulfan, fludarabine plus cytarabine) with BuCyA (busulfan, cyclophoshpamide plus cytarabine) as the conditioning regimens in allogeneic stem cell transplantation for acute leukemias. METHODS: 83 patients with acute leukemia were allocated to BFA group (busulfan 3.2 mg/(kg x d), -9 d-6 d; fludarabine 30 mg/(m2 x d), -5 d(-) -1 d; cytarabine, 1 g/(m2 x d), -5 d(-) - 1 d) or BuCyA group (busulfan, 3.2 mg/(kg x d), -8 d(-) - 5 d; cyclophoshpamide 60 mg/(kg x d),-2 d(-) - 1 d; cytarabine, 3 g/(m2 x d), -4 d(-) - 3 d). Their three-year disease-free survival (DFS) rate, complete remission (CR) rate and incidences of acute graft versus host disease (aGVHD) and hemorrhagic cystitis were monitored. RESULTS: BuCyA group had lower DFS (40.0% vs 61.9%, P = 0.039 9) and lower CR (44.0% vs 71.6%, P = 0.031 0) than BFA group. About 20% of patients treated with BuCyA were not in remission, compared with 51.6% of those treated with BFA. aGVHD occurred in 46.7% patients in the BuCyA group and 50.9% patients in the BFA group, which were 23.3% and 9.4%, respectively, for those graded III - IV. Severe infection occurred in 23.3% patients in the BuCyA group and 22.9% patients in the BFA group. Severe bleeding occurred in 26.7% patients in the BuCyA group and 11.4% patients in the BFA group. The incidence of hemorrhagic cystitis in the BuCyA group and BFA group was 16.7% and 5.7%, respectively. CONCLUSION: BFA is a safer and more effective conditioning regimen compared with BuCyA.

[Expression of tumor suppressor gene pten in patients with myelodysplastic syndrome and acute myeloid leukemia].

To study the expression and significance of pten gene in patients with myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), RT-PCR and Western blot were respectively applied to detect pten mRNA and PTEN protein in Jurkat cells (as negative control), in bone marrow nucleated cells of 35 patients with MDS, 45 patients with AML and 20 normal control. The results showed that pten mRNA expression could not be detected in Jurkat cells, and the positive rate in MDS patients (77.1%) was significantly lower than that in normal control group (90.0%) (p > 0.05), while significant difference was found between AML patients and normal control (60.0% vs 90.0%, p < 0.05); the positive rate in MDS-RAEB patients (70.0%) was lower than that in MDS-RCMD (86.7%); positive rate in de novo and relapsed AML patients (53.3%) was lower than that in AML patients in CR (73.3%), but statistics tests did not show significant difference (p > 0.05). The results of relative expression level of pten mRNA in all groups indicated that both relative expression levels in MDS patients and AML patients were definitely lower than that in normal control group (p < 0.005); the relative expression level in MDS-RAEB patients was lower than that in MDS-RCMD patients (p < 0.05); and in de novo and relapsed AML patients was obviously lower than that in AML patients in CR (p < 0.001). However, there was no significant difference between MDS and AML patients (p > 0.05). The positive rate of PTEN protein expression in both MDS (65.7%) and AML (54.8%) patients were lower than that in normal control (90.0%) (p < 0.05), and there was no significant difference when comparing MDS-RCMD patients (80.0%) with MDS-RAEB patients (55.0%) (p > 0.05), but positive rate of PTEN protein expression in de novo and relapsed AML patients (44.4%) was significantly lower than that in AML patients in CR (73.3%) (p < 0.05). It is concluded that the complete loss of pten mRNA in MDS and AML is uncommon, but the relative expression level in both diseases is significantly lower than that in normal people. The positive rates of PTEN protein expression in both MDS and AML patients are lower, compared with normal people, but are not in accordance with the expression of pten mRNA. The abnormalities of pten gene expression may be involved in the pathogenesis of MDS and AML.

[Acute myelomonocytic leukemia occurred after multiple myeloma treated: a case report].

We reported a case of multiple myeloma, who suffered from the acute myelomonocytic leukemia (AML-M4) after the chemotherapy of alkylating agent. The patient had a history of multiple myeloma and was treated with the regimen of including L-Sarcolysinum and cyclophosphamide for 5 years. The multiple myeloma of this patient was proved to have got the remission through bone marrow aspiration, immunofixation electrophoresis of serum, serum protein electrophoresis and detection of urine light chain. However, a pancytopenia of unknown cause was verified to peripheral blood. During the course of supportive treatment only with blood cell and platelet transfusion, WBC count of this patient showed a rising trend and the blast cells (8%-15%) started to occur in the peripheral blood. The further examination discovered that the ratio of blast cell was beyond 30% in bone marrow smear, and the flow cytometry detected the CD45, HLA-DR, CD13, CD33, CD64 to have the positive expressions. Thus, the diagnosis of multiple myeloma in remission and secondary AML-M4 was established. When the chemotherapy regimen to AML was being planned for this patient, she died of massive hemorrhage of gastrointestinal tract due to thrombocytopenia and ineffectiveness.