Cyclin‐dependent kinase (CDK) 1 and the murine double minute 2 homolog (MDM2)–p53 interaction are potential therapeutic targets in cancer, and their inhibition has been reported to be more ...proapoptotic in malignant cells compared to normal cells. We investigated the effect of CDK1 inhibition on p53 signaling after simultaneous dual blockade using the CDK1 inhibitor RO‐3306 and the MDM2 inhibitor Nutlin‐3 in AML. Treatment of growing AML cells with RO‐3306 induced G2/M‐phase cell cycle arrest and apoptosis in a dose‐ and time‐dependent manner. We found that RO‐3306 acts cooperatively with Nutlin‐3 to induce mitochondrial apoptosis in a cell cycle‐independent fashion. RO‐3306 downregulated expression of the antiapoptotic proteins Bcl‐2 and survivin and blocked p53‐mediated induction of p21 and MDM2. CDK1 siRNA experiments showed that reduced CDK1 expression affects p53‐induced p21 transactivation. We suggest that RO‐3306 actively enhances downstream p53 signaling to promote apoptosis and that a combination strategy aimed at both inhibiting CDK1 and activating p53 signaling is potentially effective in AML, where TP53 mutations are rare and downstream p53 signaling is intact. (Cancer Sci 2009; 100: 1128–1136)
Data characterizing the safety and effectiveness of eculizumab in patients with paroxysmal nocturnal hemoglobinuria (PNH) are limited. We describe the safety and effectiveness of eculizumab in PNH ...patients enrolled in a post-marketing surveillance study. Types and frequencies of observed adverse events were similar to those reported in previous clinical trials and no meningococcal infection was reported. Effectiveness outcomes included the reduction of intravascular hemolysis, the change in hemoglobin (Hb) level, the withdrawal of transfusion and corticosteroids, the change of renal function, and overall survival. The effect of eculizumab on intravascular hemolysis was demonstrated by a reduction in lactate dehydrogenase levels at all measurements after baseline. Significant increases in Hb levels from baseline were also observed after 1 month’s treatment with eculizumab (
p
< 0.01). Of those who were transfusion-dependent at baseline, the median number of transfusions decreased significantly from 18 to 0 unit/year after 1 year of treatment with eculizumab (
p
< 0.001). An increase in Hb and a high rate of transfusion independence were observed, especially in patients with platelet count ≥150 × 10
9
/L. Approximately 97 % of patients showed maintenance or improvement of renal function. Overall survival rate was about 90 % (median follow-up 1.9 years). These results suggest an acceptable safety profile and favorable prognosis after eculizumab intervention.
In paroxysmal nocturnal hemoglobinuria (PNH), various symptoms due to intravascular hemolysis exert a negative impact on patients’ quality of life (QOL). To determine clinical factors related with ...improvements in QOL in PNH patients treated, we analyzed changes in QOL scales in PNH patients treated with eculizumab based on data collected from post-marketing surveillance in Japan. Summary statistics were obtained using figures from QOL scoring systems and laboratory values, and evaluated by
t
test. One-year administration of eculizumab improved the most QOL items in comparison with the baseline. In particular, significant improvement of EORTC QLQ-C30 was observed in fatigue, dyspnea, physical function, and global health status. Canonical correlation analysis revealed a high correlation between QOL and laboratory values. Changes in serum lactate dehydrogenase (LDH) and hemoglobin showed strong correlations with QOL improvement. Quality of life improvement was independent of patients’ baseline characteristics of co-occurrence of bone marrow failure (BMF), or the degree of LDH. In this analysis, we found that the degree of QOL improvement was independent of the baseline LDH before eculizumab treatment and of co-occurrence of BMF. Paroxysmal nocturnal hemoglobinuria patients who have not received eculizumab treatment due to mild hemolysis may benefit from eculizumab treatment.
Immune-mediated processes are considered important in the pathogenesis of bone marrow failure syndromes (BFS). We previously reported that natural killer group 2D (NKG2D) ligands were expressed on ...pathological blood cells of patients with BFS and that NKG2D immunity may be involved in bone marrow failure. In addition to membranous NKG2D ligands on the cell surface, soluble NKG2D ligands can exist in plasma. We therefore examined the relationship between soluble NKG2D ligands and blood cell counts in 86 patients with BFS, including aplastic anemia, myelodysplastic syndrome with single lineage dysplasia, and paroxysmal nocturnal hemoglobinuria. Approximately half of the BFS patients were positive for soluble NKG2D ligands in the plasma by enzyme-linked immunosorbent assay, and soluble NKG2D ligand-positive BFS patients exhibited severe cytopenia regardless of membranous NKG2D ligand expression. In vitroanalyses demonstrated that soluble ULBP1, an NKG2D ligand, down-regulated NKG2D receptors on CD2-positive cells in peripheral blood. Moreover, soluble ULBP1 attenuated the cytotoxic effects of peripheral blood mononuclear cells on K562, which express membranous ULBP1. Our results suggest that soluble NKG2D ligands can be easy-to-measure biomarkers for the prediction of activity of immune-meditated bone marrow injury in BFS and that soluble NKG2D ligands suppress redundant immune-mediated bone marrow injury.
Paroxysmal nocturnal hemoglobinuria (PNH) is a progressive and life-threatening disease characterized by complement-mediated chronic hemolysis, resulting in serious life-threatening complications and ...early mortality. Eculizumab, a humanized anti-C5 monoclonal antibody that inhibits terminal complement activation, has been shown to reduce hemolysis in PNH patients. The pivotal open-label, 12-week phase II registration study (AEGIS) was designed to evaluate the efficacy and safety of eculizumab in Japanese patients with PNH. This trial achieved its primary endpoint of reducing intravascular hemolysis with high statistical significance. Twenty-seven of the 29 patients responded to eculizumab treatment, resulting in an 87% reduction in hemolysis (
P
< 0.0001) and subsequent improvement in anemia (
P
= 0.0003) despite reduction in transfusion requirements (
P
= 0.006). Fatigue and dyspnea significantly improved within 1–2 weeks of eculizumab treatment and the improvement was independent of changes in hemoglobin. Chronic kidney disease (CKD) was common (66%) and eculizumab treatment improved CKD in 41% of patients at 12 weeks (
P
< 0.001). Elevated thrombotic risk was evident in Japanese PNH patients and eculizumab treatment normalized
d
-dimer levels in 45% of patients with elevated
d
-dimers at baseline (
P
< 0.001). The AEGIS results demonstrate that eculizumab is effective, safe and well tolerated in Japanese patients with PNH.
MicroRNA142 (MIR142)
is a target of chromosome translocations and mutations in human B-cell lymphomas. We analyzed an aggressive B-cell lymphoma carrying t(8;17)(q24;q22) and t(6;14)(p21;q32), and ...sought to explore the role(s) of
MIR142
in lymphomagenesis. t(8;17)(q24;q22) involved
MYC
on 8q24 and pri-
MIR142
on 17q22.
MYC
was activated by a promoter substitution by t(8;17)(q24;q22). t(8;17)(q24;q22) was an additional event after t(6;14) (p21;q32), which caused the over-expression of
CCND3
. Southern blot analyses revealed that the
MIR142
locus was deleted from the affected allele, whereas Northern analyses showed over-expression of
MIR142
in tumor cells. Although previous studies reported an over-expression of mutations in
MIR142
in B-cell lymphomas, limited information is available on the functions of
MIR142
in lymphomagenesis. Therefore, we generated bone marrow transplantation (BMT) and transgenic (Eμ/mir142) mice, which showed enforced expression in hematopoietic progenitor cells and B cells, respectively. BMT mice showed decreased numbers of all lineage-positive cells, particularly B cells, in peripheral blood. Eμ/mir142 mice showed decreased numbers of IgM-positive splenocytes, and exhibited altered B-cell phenotypic changes induced by lipopolysaccharide. Our results suggest that over-expression of
MIR142
alters B-cell differentiation, implying multi-step lymphomagenesis together with
MYC
activation and
CCND3
over-expression.
: To determine and directly compare the clinical course of white and Asian patients with paroxysmal nocturnal hemoglobinuria (PNH), data were collected for epidemiologic analysis on 176 patients from ...Duke University and 209 patients from Japan. White patients were younger with significantly more classical symptoms of PNH including thrombosis, hemoglobinuria, and infection, while Asian patients were older with more marrow aplasia. The mean fraction of CD59-negative polymorphonuclear cells (PMN) at initial analysis was higher among Duke patients than Japanese patients. In both cohorts, however, a larger PNH clone was associated with classical PNH symptoms, while a smaller PNH clone was associated with marrow aplasia. Thrombosis was significantly more prevalent in white patients than Asian patients, and was associated with a significantly higher proportion of CD59-negative PMN. For individual patients, CD59-negative populations varied considerably over time, but a decreasing PNH clone portended hematopoietic failure. Survival analysis revealed a similar death rate in each group, although causes of death were different and significantly more Duke patients died from thrombosis. Japanese patients had a longer mean survival time (32.1 yr vs. 19.4 yr), although Kaplan-Meier survival curves were not significantly different. Poor survival in both groups was associated with age over 50 years, severe leukopenia/neutropenia at diagnosis, and severe infection as a complication; additionally, thrombosis at diagnosis or follow-up for Duke patients and renal failure for Japanese patients were poor prognostic factors. These data identify important differences between white and Asian patients with PNH. Identification of prognostic factors will help the design of prospective clinical trials for PNH.
The mechanism by which paroxysmal nocturnal hemoglobinuria (PNH) clones expand is unknown. PNH clones harbor PIGA mutations and do not synthesize glycosylphosphatidylinositol (GPI), resulting in ...deficiency of GPI-linked membrane proteins. GPI-deficient blood cells often expand in patients with aplastic anemia who sustain immune-mediated marrow injury putatively induced by cytotoxic cells, hence suggesting that the injury allows PNH clones to expand selectively. We previously reported that leukemic K562 cells preferentially survived natural killer (NK) cell-mediated cytotoxicity in vitro when they acquired PIGA mutations. We herein show that the survival is ascribable to the deficiency of stress-inducible GPI-linked membrane proteins ULBP1 and ULBP2, which activate NK and T cells. The ULBPs were detected on GPI-expressing but not on GPI-deficient K562 cells. In the presence of antibodies to either the ULBPs or their receptor NKG2D on NK cells, GPI-expressing cells were as less NK sensitive as GPI-deficient cells. NK cells therefore spared ULBP-deficient cells in vitro. The ULBPs were identified only on GPI-expressing blood cells of a proportion of patients with PNH but none of healthy individuals. Granulocytes of the patients partly underwent killing by autologous cytotoxic cells, implying ULBP-associated blood cell injury. In this setting, the lack of ULBPs may allow immunoselection of PNH clones.
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, progressive hematopoietic stem cell disorder characterized by chronic complement-mediated hemolysis leading to life-threatening complications and ...early mortality. Eculizumab, a humanized anti-C5 monoclonal antibody, inhibits terminal complement activation, reduces hemolysis, decreases the risk of thrombosis, and improves renal function and quality of life in PNH patients. The long-term efficacy and safety of eculizumab in Japanese patients were assessed in a 2-year extension to a 12-week, open-label study (AEGIS). Eculizumab treatment led to an immediate and sustained reduction in intravascular hemolysis (
P
< 0.001) and red blood cell transfusions (
P
= 0.0016) compared with baseline levels. There were no reports of thromboembolism during eculizumab treatment. The majority of patients had stable (56 %) or improved (41 %) renal function and an improved quality of life (
P
= 0.015), with sustained reductions in fatigue and dyspnea. Eculizumab was well tolerated; no deaths or serious hemolytic events were reported, and the rate of infections declined over time. There were no significant differences in the response to eculizumab in patients with or without bone marrow dysfunction. These results demonstrate that eculizumab is an effective, well-tolerated long-term treatment for Japanese PNH patients and leads to continued amelioration of some hemolytic complications.
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