INPP4B overexpression is associated with poor clinical outcome and therapy resistance in acute myeloid leukemia.

In this study, we investigated the role of inositol polyphosphate-4-phosphatase, type-II (INPP4B) in acute myeloid leukemia (AML). We observed that AML patients with high levels of INPP4B (INPP4B(high)) had poor response to induction therapy, shorter event-free survival and shorter overall survival. Multivariate analyses demonstrated that INPP4B(high) was an independent predictor of poor prognosis, significantly improving current predictive models, where it outperformed conventional biomarkers including FLT3-ITD and NPM1. Furthermore, INPP4B(high) effectively segregated relative risk in AML patients with normal cytogenetics. The role of INPP4B on the biology of leukemic cells was assessed in vitro. Overexpression of INPP4B in AML cell lines enhanced colony formation potential, recapitulated the chemotherapy resistance observed in AML patients and promoted proliferation in a phosphatase-dependent, and Akt-independent manner. These findings reveal that INPP4B(high) has an unexpected role consistent with oncogenesis in AML, in contrast to its previously reported tumor-suppressive role in epithelial cancers. Overall, we propose that INPP4B is a novel prognostic biomarker in AML that has potential to be translated into clinical practice both as a disease marker and therapeutic target.

Co-transplantation of third-party umbilical cord blood-derived MSCs promotes engraftment in children undergoing unrelated umbilical cord blood transplantation.

Success of umbilical cord blood transplantation (UCBT) has been limited by a high rate of graft failure and delayed hematological recovery. It has been postulated that MSCs have hematopoiesis-supportive properties. Therefore, to overcome the limitation of UCBT, third-party UCB-derived MSCs were co-transplanted in recipients receiving unrelated UCBT. Seven patients received UCB and third-party UCB-MSCs. Hematopoietic recovery and transplantation outcomes were compared with historic controls. There was no acute toxicity associated with the infusion of MSCs. The median day to neutrophil engraftment was 19 days in patients, as compared with 24 days in controls (P=0.03). The median day of platelet engraftment was 47 days and 57 days in patients and controls, respectively (P=0.26). In addition, there was no engraftment failure in the MSC group. The incidence of acute and chronic GVHD was comparable between the two groups. However, veno-occlusive disease and TRM did not occur in the MSC group. Third-party UCB-MSCs infusion was safe and feasible. MSCs may also enhance the engraftment of UCBT and prevent rejection. In addition, MSCs may have a role in decreasing TRM. Randomized, controlled trials are required to confirm these results and longer follow-up will determine the effects of MSCs on the risk of relapse.

Tandem high-dose chemotherapy and autologous stem cell transplantation in patients with high-risk neuroblastoma: results of SMC NB-2004 study.

From January 2004 to December 2008, 50 consecutive patients with high-risk neuroblastoma were assigned to receive tandem HDCT (high-dose chemotherapy)/auto-SCT after nine cycles of induction chemotherapy. CEC (carboplatin + etoposide + cyclophosphamide) regimen and TM (thiotepa + melphalan)-TBI regimen (or TM regimen for stage 3 patients) were the first and second HDCT regimens. Local radiotherapy, differentiation therapy with 13-cis-retinoid acid and immunotherapy with interleukin-2 were given after tandem HDCT/auto-SCT. Of the 50 patients, 49 underwent a first HDCT/auto-SCT and 47 underwent a second HDCT/auto-SCT. The tumor relapsed or progressed in 14 patients, secondary malignancy developed in one patient and one patient died from chronic lung disease. Therefore, 34 patients remained event free with a median follow-up of 54.5 months (range, 14-94 months) from diagnosis. The probabilities of 5-year OS and EFS for all 50 patients were 77.0% (95% confidence interval (CI), 63.7-90.3) and 71.4% (95% CI, 58.7-84.1), respectively. However, all patients who remained event free for >3 years after tandem HDCT/auto-SCT experienced late adverse effects. Chemotherapeutic dose-escalation strategy using tandem HDCT/auto-SCT was very encouraging for survival. However, further studies incorporating newer treatment modalities are needed to reduce late adverse effects without jeopardizing the survival rate.

An orally active cathepsin K inhibitor, furan-2-carboxylic acid, 1-{1-[4-fluoro-2-(2-oxo-pyrrolidin-1-yl)-phenyl]-3-oxo-piperidin-4-ylcarbamoyl}-cyclohexyl)-amide (OST-4077), inhibits osteoclast activity in vitro and bone loss in ovariectomized rats.

Human cathepsin K, a cysteine proteinase of the papain family, has been recognized as a potential drug target for the treatment of osteoporosis. The predominant expression of cathepsin K in osteoclasts has rendered the enzyme into a major target for the development of novel antiresorptive drugs. Now, we report the pharmacological properties of OST-4077 [furan-2-carboxylic acid (1-{1-[4-fluoro-2-(2-oxo-pyrrolidin-1-yl)-phenyl]-3-oxo-piperidin-4-ylcarbamoyl}-cyclohexyl)-amide] as a novel selective cathepsin K inhibitor. Human and rat cathepsin K were inhibited in vitro by OST-4077 with the IC50 values of 11 and 427 nM, respectively. OST-4077 suppressed bone resorption induced by rabbit osteoclasts (IC50, 37 nM) but did not affect bone mineralization or cellular alkaline phosphatase activity in MC3T3-E1 cells. Parathyroid hormone-induced bone resorption was inhibited in a dose-dependent manner in thyroparathyroidectomized rats gavaged with a single dose of OST-4077 (ED50, 69 mg/kg). When given orally twice daily for 4 weeks to 3-month-old ovariectomized (OVX) rats, OST-4077 dose-dependently prevented bone loss, as monitored by bone densitometry, ash content, and urinary excretion of deoxypyridinoline. No change in serum osteocalcin in the OVX rats by OST-4077 suggested that bone formation might not be affected by the agent. In summary, OST-4077 selectively inhibited bone resorbing activities of osteoclasts and prevented bone loss induced by estrogen deficiency but did not affect bone formation. OST-4077, an orally active selective human cathepsin K inhibitor, may have the therapeutic potential for the treatment of diseases characterized by excessive bone loss including osteoporosis.

Epidemiologic evidence of a relationship between airway hyperresponsiveness and exposure to polluted air.

BACKGROUND: There has been an increase in allergic diseases as a result of increased air pollution emanating from traffic and various industries. OBJECTIVE: This study evaluated the association between air pollution and airway hyperresponsiveness in a cross-sectional study of a cohort of 670 children, aged 10-13 years. METHODS: We measured spirometry and conducted allergic skin tests and methacholine challenge tests in 670 schoolchildren. The methacholine concentration causing a 20% fall in FEV1 (PC20) was used as the threshold of airway hyperresponsiveness (AHR). Thresholds of 16 mg/dl or less were assumed to indicate AHR. RESULTS: All of the schoolchildren had normal pulmonary function. Of the children, 257 (38.3%) had AHR. There was a significant increase in AHR in schoolchildren living near a chemical factory [45.0% (138/306), 6.50 +/- 0.48] compared to those in rural [31.9% (52/163), 9.84 +/- 0.83] and coastal [33.3% (67/201), 7.17 +/- 0.68] areas. Atopy was significantly more prevalent near the chemical factory vs the coastal and rural areas [35.6% (109/306) vs 27.3% (55/201) and 23.3% (38/163), respectively, P < 0.007]. Schoolchildren with atopy had lower PC20 than those without atopy (5.98 +/- 0.60 vs 8.15 +/- 0.45, P < 0.001). Positive allergy skin tests and living in a polluted area were risk factors in multivariate analyses adjusted for sex, parents' smoking habits, age, body mass index, nose symptoms and lung symptoms (odds ratio for location = 2.4875, confidence interval 1.6542-3.7406, P < 0.000; odds ratio for allergy skin test = 1.5782, confidence interval 1.1130-2.2379, P < 0.0104). CONCLUSION: Our findings demonstrate that more children living in polluted areas have airway hyperresponsiveness than do those living in less polluted areas.

Potentiation of cadmium-induced cytotoxicity by sulfur amino acid deprivation through activation of extracellular signal-regulated kinase1/2 (ERK1/2) in conjunction with p38 kinase or c-jun N-terminal kinase (JNK). Complete inhibition of the potentiated toxicity by U0126 an ERK1/2 and p38 kinase inhibitor.

The mechanisms of cadmium-induced toxicity may include oxidative stress, altered redox homeostasis, and injuries to organelles. The current study was designed to study the effect of decreased cellular glutathione (GSH) content by sulfur amino acid deprivation on cadmium toxicity and to identify the signaling pathways responsible for the cytotoxicity. GSH content was increased by cadmium in H4IIE cells prior to cell death, which was prevented by excess GSH or cysteine. Cell viability, however, was not improved by GSH or cysteine complexation of cadmium. Cadmium-induced cytotoxicity was 40-fold potentiated in cells with decreased GSH by sulfur amino acid deprivation. Cadmium in combination with decreased GSH markedly increased apoptotic cell death. Mitogen-activated protein kinases including extracellular signal-regulated kinase 1/2, p38 kinase and c-Jun N-terminal kinase (JNK) were all activated 1-12 hr after sulfur amino acid deprivation. U0126 (1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene), which inhibited activation of extracellular signal-regulated kinase1/2 and p38 kinase in cells under sulfur amino acid deprivation, completely prevented potentiation in Cd-induced cytotoxicity and apoptosis. Potentiation of cadmium toxicity by sulfur amino acid deprivation was prevented in part by either PD98059 or SB203580, or in cells stably expressing dominant negative mutant of JNK1, and to greater extents by PD98059 in combination with either SB203580 or JNK1(-) transfection. These results demonstrated that decreased cellular GSH content potentiated cytotoxicity induced by cadmium at the level of human exposure, and that the potentiation of cytotoxicity resulted from activation of extracellular signal-regulated kinase1/2 in conjunction with p38 kinase or JNK.

DA-125, a novel anthracycline derivative showing high-affinity DNA binding and topoisomerase II inhibitory activities, exerts cytotoxicity via c-Jun N-terminal kinase pathway.

PURPOSE: DA-125 [(8S,10S)-8-(3-Aminopropanoyloxyacetyl)-10-[(2,6-dideoxy-2-fluoro-alpha-L-talopyranosyl) oxy]-7,8,9,10-tetrahydro-6,8,11-trihydroxy-1-methoxy-5,12-naphthacene-dione hydrochloride] is a novel anthracycline derivative with anticancer activity. In the present study, we compared the cytotoxicity of DA-125 with that of doxorubicin in H4IIE rat hepatoma cells and investigated the mechanistic basis. Because activation of MAP kinases, in particular c-Jun N-terminal kinase (JNK), is implicated in apoptotic cell death, the signaling pathways responsible for DA-125-induced apoptosis were studied. METHODS: Cytotoxicity and apoptosis were measured in H4IIE cells and cells were stably transfected with a dominant-negative mutant of JNK1 (JNK1-) by MTT and TUNEL assays. Inhibition of topoisomerase II activity was determined in vitro. Drug accumulation and DNA binding affinity were determined by fluorescence spectroscopy. RESULTS: The cytotoxicity of DA-125 was greater than that of doxorubicin (IC50 11.5 vs 70 microM). DA-125 induced apoptosis with 30-fold greater potency than doxorubicin. Inhibition of topoisomerase II by DA-125 was fourfold greater. The presence of excess beta-alanine, a DA-125 moiety, failed to alter cytotoxicity and accumulation of DA-125, indicating that the improved cytotoxicity of DA-125 did not result from the beta-alanine moiety. Greater cellular accumulation of DA-125 correlated with its high-affinity DNA binding. Although neither PD98059 nor SB203580 altered the degree of cytotoxicity induced by DA-125, JNK1 cells exhibited about a twofold greater viability than control cells. DA-125-induced apoptosis was also decreased in JNK1- -transfected cells. CONCLUSIONS: DA-125 potently inhibited topoisomerase II activity and induced apoptosis by a high rate of prooxidant production. DA-125 exhibited high-affinity DNA binding with improved cellular drug accumulation. Apoptosis induced by DA-125 involved the pathway of JNK1, but not ERK1/2 or p38 kinase.

Potentiation of arsenic-induced cytotoxicity by sulfur amino acid deprivation (SAAD) through activation of ERK1/2, p38 kinase and JNK1: the distinct role of JNK1 in SAAD-potentiated mercury toxicity.

Sulfur amino acid deficiency occurs in certain pathophysiological situations (e.g. protein-calorie malnutrition). Previous studies revealed that sulfur amino acid deprivation (SAAD) activated MAP kinases and potentiated cadmium-induced cytotoxicity by activation of ERK1/2 in conjunction with p38 kinase or JNK. The present study was designed to determine susceptibility of cells to a variety of heavy metals in combination with SAAD. Viability was assessed in H4IIE cells treated with sodium arsenite, mercuric chloride, sodium selenite, lead acetate, chromium trioxide or manganese chloride. SAAD potentiated the cytotoxicity of H4IIE cells by arsenic or mercury (i.e. EC50, 19 and 5 microM in SAAD vs. 401 and 42 microM in control medium, respectively). TUNEL assays revealed that the potentiated arsenic or mercury toxicity involved apoptotic cell death. Lead or selenite moderately elicited cell death, which was not enhanced by SAAD. Chromium or manganese caused no significant cytotoxicity. Treatment of cells with U0126 [1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)butadiene] an ERK1/2 inhibitor or SB203580 [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole] a p38 kinase inhibitor effectively prevented SAAD-potentiated arsenic toxicity. The potentiated arsenic toxicity was also inhibited in cells stably expressing a dominant negative mutant of c-Jun N-terminal kinase 1 [JNK1(-)]. The inhibitors of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 kinase failed to prevent mercury-induced toxicity enhanced by SAAD. JNK1(-) cells were minimally susceptible to mercury in SAAD medium. These results demonstrated that SAAD potentiated cytotoxicity induced by arsenic or mercury and that activation of ERK1/2, p38 kinase and JNK1 was responsible for the potentiated arsenic toxicity, whereas the mercury toxicity enhanced by SAAD was mediated with the activity of JNK1.