Loss of p53 induces leukemic transformation in a murine model of Jak2 V617F-driven polycythemia vera.

As leukemic transformation of myeloproliferative neoplasms (MPNs) worsens the clinical outcome, reducing the inherent risk of the critical event in MPN cases could be beneficial. Among genetic alterations concerning the transformation, the frequent one is TP53 mutation. Here we show that retroviral overexpression of Jak2 V617F mutant into wild-type p53 murine bone marrow cells induced polycythemia vera (PV) in the recipient mice, whereas Jak2 V617F-transduced p53-null mice developed lethal leukemia after the preceding PV phase. The leukemic mice had severe anemia, hepatosplenomegaly, pulmonary hemorrhage and expansion of dysplastic erythroid progenitors. Primitive leukemia cells (c-kit+Sca1+Lin- (KSL) and CD34-CD16/32-c-kit+Sca1-Lin- (megakaryocyte-erythroid progenitor; MEP)) and erythroid progenitors (CD71+) from Jak2 V617F-transduced p53-null leukemic mice had leukemia-initiating capacity, however, myeloid differentiated populations (Mac-1+) could not recapitulate the disease. Interestingly, recipients transplanted with CD71+ cells rapidly developed erythroid leukemia, which was in sharp contrast to leukemic KSL cells to cause lethal leukemia after the polycythemic state. The leukemic CD71+ cells were more sensitive to INCB18424, a potent JAK inhibitor, than KSL cells. p53 restoration could ameliorate Jak2 V617F-transduced p53-null erythroleukemia. Taken together, our results show that p53 loss is sufficient for inducing leukemic transformation in Jak2 V617F-positive MPN.

BAALC potentiates oncogenic ERK pathway through interactions with MEKK1 and KLF4.

Although high brain and acute leukemia, cytoplasmic (BAALC) expression is a well-characterized poor prognostic factor in acute myeloid leukemia (AML), neither the exact mechanisms by which BAALC drives leukemogenesis and drug resistance nor therapeutic approaches against BAALC-high AML have been properly elucidated. In this study, we found that BAALC induced cell-cycle progression of leukemia cells by sustaining extracellular signal-regulated kinase (ERK) activity through an interaction with a scaffold protein MEK kinase-1 (MEKK1), which inhibits the interaction between ERK and MAP kinase phosphatase 3 (MKP3/DUSP6). BAALC conferred chemoresistance in AML cells by upregulating ATP-binding cassette proteins in an ERK-dependent manner, which can be therapeutically targeted by MEK inhibitor. We also demonstrated that BAALC blocks ERK-mediated monocytic differentiation of AML cells by trapping Krüppel-like factor 4 (KLF4) in the cytoplasm and inhibiting its function in the nucleus. Consequently, MEK inhibition therapy synergizes with KLF4 induction and is highly effective against BAALC-high AML cells both in vitro and in vivo. Our data provide a molecular basis for the role of BAALC in regulating proliferation and differentiation of AML cells and highlight the unique dual function of BAALC as an attractive therapeutic target against BAALC-high AML.

[A case of neuroleptic malignant syndrome with acute renal failure].

Neuroleptic malignant syndrome is a potentially lethal side effect of neuroleptic drugs, characterized by fever, muscle rigidity, autonomic dysfunction, and altered consciousness. A 50-year-old female hospitalized three times in the past for psychiatric treatment was admitted to Umayabashi Hospital for treatment of a relapse of a schizophrenic psychosis. She had received 50 mg of chlorpromazine and one tablet of Vegetamin-A (chlorpromazine 25 mg, promethazine 12.5 mg, phenobarbital 40 mg). Approximately 24-36 hours later, the patient became febrile and lost consciousness, and eight days later, acute renal failure occurred with muscle rigidity. She was transported to Maebashi Red Cross Hospital to receive hemodialysis. On admission, the laboratory studies showed high levels of serum creatine phosphokinase, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, creatinine and blood urea nitrogen. She underwent hemodialysis for treatment of acute renal failure and recovered from it after 16 sessions of hemodialysis.

The clinical role of procalcitonin in hematopoietic SCT.

Infectious disease following hematopoietic SCT (HSCT) is a major cause of TRM. The more valuable markers to distinguish infections disease from non-infectious complications are needed. Procalcitonin (PCT) and C-reactive protein (CRP) were measured periodically throughout the clinical course of consecutive 28 patients who underwent HSCT. The diagnoses of 103 febrile episodes were analyzed. PCT and CRP level on the first day of fever significantly increased in systemic bacterial or fungal infection (P<0.001 and <0.001, respectively). PCT is more valuable than CRP for discrimination between systemic bacterial or fungal infection and intracellular infection (P=0.022 and 0.447, respectively). The area under receiver-operator characteristics curve for detection of bacterial or fungal infection was 0.82 for PCT and 0.76 for CRP. When PCT levels did not increase over 0.25 ng/mL through the fifth day of fever, PCT yielded a specificity of 100.0%. In multivariate analysis, the maximum level of PCT during a whole course of HSCT>=2 ng/mL was independently associated with worse overall survival as post-transplant predictors (adjusted hazard ratio 6.42, P=0.035). PCT provide additional information for discrimination between bacterial or fungal infection and other causes and predicting the patient's prognosis after HSCT.

[Combination therapy of renal cell carcinoma with interferon-alpha and UFT (or FT-207)].

Human lymphoblastoid interferon (IFN-alpha MOR-22; OIF) was administered to forty-two patients suffering from renal cell carcinoma. Twenty-six patients with metastatic lesions or primary tumor were treated in a clinical trial with either MOR-22 alone or combination of MOR-22 and UFT (or FT-207). The efficacy was assessed in ten of twenty patients who had received MOR-22 alone for more than eight weeks, but objective response was not observed. The efficacy was done in eight of fourteen patients with MOR-22 and UFT (or FT-207) in combination. Complete response was achieved in one, and partial response in two, with an objective response rate of 37.5%. But the difference was no statistically significant in the survival rate of each therapy. In evaluable twenty patients with MOR-22 prophylactically, there was only one case who had occurred lung metastases with a refractory rate of 8.3%. Forty-one patients were examined for side effects to drugs. The main side effects were fever, anorexia, general fatigue, hematologic toxicities, and hepatic dysfunction in both therapy. These side effects occurred with more increased frequency in combination therapy of UFT (or FT-207) compared to MOR-22 alone.