Shinji Kishi

Evaluation of staging and early response to chemotherapy with whole‐body diffusion‐weighted MRI in malignant lymphoma patients: A comparison with FDG‐PET/CT

To examine the utility of diffusion‐weighted MRI (DW‐MRI) for staging and early response to chemotherapy assessment in lymphoma patients as compared with fluorodeoxyglucose positron emission tomography/computed tomography (FDG‐PET/CT).

Glutathione S‐transferase M1 inhibits dexamethasone‐induced apoptosis in association with the suppression of Bim through dual mechanisms in a lymphoblastic leukemia cell line

(Cancer Sci 2010; 101: 767–773)

Fludarabine-mediated circumvention of cytarabine resistance is associated with fludarabine triphosphate accumulation in cytarabine-resistant leukemic cells

The combination of cytarabine (ara-C) with fludarabine is a common approach to treating resistant acute myeloid leukemia. Success depends on a fludarabine triphosphate (F-ara-ATP)-mediated increase in the active intracellular metabolite of ara-C, ara-C 5’-triphosphate (ara-CTP). Therapy-resistant leukemia may exhibit ara-C resistance, the mechanisms of which might induce cross-resistance to fludarabine with reduced F-ara-ATP formation. The present study evaluated the effect of combining ara-C and fludarabine on ara-C-resistant leukemic cells in vitro. Two variant cell lines (R1 and R2) were 8-fold and 10-fold more ara-C resistant, respectively, than the parental HL-60 cells. Reduced deoxycytidine kinase activity was demonstrated in R1 and R2 cells, and R2 cells also showed an increase in cytosolic 5’-nucleotidase II activity. Compared with HL-60 cells, R1 and R2 cells produced smaller amounts of ara-CTP. Both variants accumulated less F-ara-ATP than HL-60 cells and showed cross-resistance to fludarabine nucleoside (F-ara-A). R2 cells, however, accumulated much smaller amounts of F-ara-ATP and were more F-ara-A resistant than R1 cells. In HL-60 and R1 cells, F-ara-A pretreatment followed by ara-C incubation produced F-ara-ATP concentrations sufficient for augmenting ara-CTP production, thereby enhancing ara-C cytotoxicity. No potentiation was observed in R2 cells. Nucleotidase might preferentially degrade F-ara-A monophosphate over ara-C monophosphate, leading to reduced F-ara-ATP production and thereby compromising the F-ara-A-mediated potentiation of ara-C cytotoxicity in R2 cells. Thus, F-ara-A-mediated enhancement of ara-C cytotoxicity depended on F-ara-ATP accumulation in ara-C-resistant leukemic cells but ultimately was associated with the mechanism of ara-C resistance.

Marked upregulation of Survivin and Aurora-B kinase is associated with disease progression in the myelodysplastic syndromes.

Background Myelodysplastic syndromes are a heterogeneous group of clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis. Survivin is a member of the inhibitor of apoptosis family and suppresses apoptosis. Survivin also functions as a subunit of the chromosomal passenger complex for regulating mitosis with Aurora-B. Survivin and Aurora-B play an important role in maintaining genome stability. The aim of this study was to determine the role of Survivin and Aurora-B kinase in disease progression and prognosis of myelodysplastic syndromes. Design and Methods We evaluated the expression levels of these two genes in CD34+ cells prepared from 64 patients with myelodysplastic syndrome or leukemic blasts from 50 patients with de novo acute myeloid leukemia using quantitative real-time PCR. Results Survivin and Aurora-B expression levels were highly correlated with the type of myelodysplastic syndrome, were much higher in refractory anemia with excess blasts-1, refractory anemia with excess blasts-2, and secondary acute myeloid leukemia following myelodysplastic syndrome than in normal control, and increased during disease progression. There was a significant correlation between these expression levels and the International Prognostic Scoring System. Interestingly, these levels were remarkably higher in patients with secondary acute myeloid leukemia following myelodysplastic syndromes than in those with de novo acute myeloid leukemia. Conclusions This is the first report showing that high levels of Survivin and Aurora-B kinase expression in CD34+ cells are distinctive molecular features of high-risk myelodysplastic syndromes and secondary acute myeloid leukemia following myelodysplastic syndrome. Marked upregulation of Survivin and Aurora-B kinase may contribute to genetic instability and disease progression of myelodysplastic syndromes. Our data may explain why patients with high-risk myelodysplastic syndromes frequently show complex chromosomal abnormality.

Utility of PCR amplification and DNA microarray hybridization of 16S rDNA for rapid diagnosis of bacteremia associated with hematological diseases

OBJECTIVES The rapid diagnosis of bacteremia is crucial for patient management including the choice of antimicrobial therapy, especially in cases of hematological disease, because neutropenia occurs frequently during antineoplastic chemotherapy or disease progression. We describe a rapid detection and identification system that uses universal PCR primers to amplify a variable region of bacterial 16S ribosomal DNA (rDNA), followed by DNA microarray hybridization. METHODS Probes for 72 microorganisms including most causal clinical pathogens were spotted onto a microarray plate. The DNA microarray and conventional methods of identification were applied to 335 cultures from patients with hematological diseases. RESULTS Forty-one samples (12.2%) tested positive by conventional blood culture test in a few days, while 40 cases (11.9%) were identified by the new method within 24 h. The sensitivity and specificity of this new method were 93% and 99%, respectively, compared with conventional blood culture testing. CONCLUSIONS PCR combined with a DNA microarray is useful for the management of febrile patients with hematological diseases.

Monitoring of intracellular 1-beta-D-arabinofuranosylcytosine 5'-triphosphate in 1-beta-D-arabinofuranosylcytosine therapy at low and conventional doses.

1‐β‐D‐Arabinofuranosylcytosine (ara‐C) is used empirically at a low, conventional, or high dose. Ara‐C therapy may be optimal if it is directed by the clinical pharmacokinetics of the intracellular active metabolite of ara‐C, 1‐β‐D‐arabinofuranosylcytosine 5′‐triphosphate (ara‐CTP). However, ara‐CTP has seldom been monitored during low‐ and conventional‐dose ara‐C therapies because detection methods were insufficiently sensitive. Here, with the use of our newly established method (Cancer Res., 56, 1800‐1804 (1996), ara‐CTP was monitored in leukemic cells from acute myelog‐enous leukemia patients receiving low‐ or conventional‐dose ara‐C [subcutaneous ara‐C administration (10 mg/m2) (3 patients), continuous ara‐C infusion (20 or 70 mg/m2/24 h) (7 patients), 2‐h ara‐C infusion (70 mg/m2) (4 patients), and 2‐h infusion of N4‐behenoyl‐l‐β‐D‐arabinofuranosylcy‐tosine, a deaminase‐resistant ara‐C derivative (70 mg/m2) (6 patients)]. Ara‐CTP could be determined at levels under 1μM. There was a close correlation between the elimination half‐life values of the plasma ara‐C and the intracellular ara‐CTP. The presence of ara‐C in the plasma was important to maintain ara‐CTP. The continuous ara‐C and the 2‐h N4‐behenoyl‐l‐β‐D‐arabinofura‐nosylcytosine infusions maintained ara‐CTP and the plasma ara‐C longer than the subcutaneous ara‐C or the 2‐h ara‐C infusion. They also afforded relatively higher ara‐CTP concentrations, and consequently produced ara‐CTP more efficiently than the 2‐h ara‐C infusion. Different administration methods produced different quantities of ara‐CTP even at the same dose.

Effect of PSC 833 on the cytotoxicity and pharmacodynamics of mitoxantrone in multidrug-resistant K562 cells.

We examined the effect of PSC 833, a nonimmunosuppressive cyclosporin analogue, on the cytotoxicity, accumulation and retention of an anthraquinone antileukemia drug mitoxantrone (MIT). This was done in P-glycoprotein (PGP)-overexpressing multidrug-resistant K562/D1-9 cells and compared with the effect of cyclosporin A (CsA). We also compared MIT with the effect of PSC 833 on the cytotoxicity of daunorubicin (DNR) and doxorubicin (DOX). While PSC 833 and CsA had no effect on the cytotoxicity, accumulation and retention of MIT in the parent K562 cells, PSC 833 and CsA restored accumulation and retention of MIT in K562/D1-9 cells dose-dependently. Consequently, there was increased sensitivity of K562/D1-9 cells to MIT. The reversing activity of PSC 833 on the cytotoxicity of MIT was stronger than that of CsA, and was almost the same as the reversing activity of PSC 833 on the cytotoxicity of DNR and DOX. The resistance index of MIT decreased from 43.9-fold to 2.8-fold by 0.4 microM PSC 833, which is a clinically achievable plasma concentration. These results suggest that the combination of PSC 833 with MIT could be a promising treatment in reversing PGP-mediated MDR in leukemia patients.

Close Correlation of 1‐β‐D‐Arabinofuranosylcytosine 5′‐Triphosphate, an Intracellular Active Metabolite, to the Therapeutic Efficacy of N4‐Behenoyl‐1‐β‐D‐arabinofuranosylcytosine Therapy for Acute Myelogenous Leukemia

N4‐Behenoyl‐l‐β‐D‐arabinofuranosylcytosine (BHAC), a prodrug of 1‐β ‐D‐arabinofuranosylcy‐tosine, is used effectively for the treatment of leukemia in Japan. BHAC therapy may be more effective if it is delivered in conjunction with monitoring of 1‐β ‐D‐arabinofuranosylcytosine 5′‐tri‐phosphate (ara‐CTP), the intracellular active metabolite of ara‐C derived from BHAC. However, previous monitoring methods for ara‐CTP were insufficiently sensitive. Here, using our new sensitive method, we evaluated the ara‐CTP pharmacokinetics in relation to the therapeutic response in 11 acute myelogenous leukemia patients who received a 2‐h infusion of BHAC (70 mg/m2) in combination remission induction therapy. ara‐CTP could be monitored at levels under 1 μM. BHAC maintained effective levels of plasma ara‐C and intracellular ara‐CTP for a longer time, even compared with historical values of high‐dose ara‐C. The area under the concentration‐time curve of ara‐CTP was significantly greater in the patients with complete remission than in the patients without response. This greater amount of ara‐CTP was attributed to the higher ara‐CTP concentrations achieved in the responding patients. There was no apparent difference of plasma ara‐C pharmacokinetics between the two groups. Thus, for the first tune, the ara‐CTP pharmacokinetics was evaluated in relation to the therapeutic effect of BHAC, and the importance of ara‐CTP was proven. Administration of optimal BHAC therapy may require monitoring of the ara‐CTP pharmacokinetics in each individual patient.

Controlling serum uric acid using febuxostat in cancer patients at risk of tumor lysis syndrome

Tumor lysis syndrome (TLS) is a life-threatening oncological emergency, in which control of serum uric acid (S-UA) levels is important. S-UA-lowering efficacy of a new xanthine oxidase inhibitor, febuxostat, was retrospectively evaluated in seven patients with hematological malignancies who were at an intermediate risk of developing TLS. A 10-mg dose of febuxostat was initiated and chemotherapy was started within 24 h of administering the first dose of febuxostat. Febuxostat was continued until at least day 7 of chemotherapy treatment. The UA-lowering treatment was considered effective if febuxostat reduced S-UA levels to ≤7.5 mg/dl by day 5. The mean S-UA level at base line was 6.4±2.6 mg/dl and, on day 5, the mean S-UA level was 4.7±1.8 mg/dl. All the patients achieved S-UA levels ≤7.5 mg/dl. Serum creatinine levels decreased from 0.93±0.25 to 0.85±0.25 mg/dl. The estimated glomerular filtration rate values increased from 69.7±24.5 to 76.9±26.2 ml/min. No adverse reactions were noted during the study period and no patients experienced progressive TLS. Successful control of S-UA and improved renal function were obtained in response to febuxostat treatment in cancer patients at a risk of TLS.

Peripheral blood stem cell collection and transplantation using the Haemonetics Multi Component System

AIM To assess clinical usefulness of an intermittent-flow blood cell separator in peripheral blood stem cell (PBSC) collection and transplantation. RESULTS The Haemonetics Multi Component System (Multi) was used to collect PBSC (52 aphereses in 17 patients). The mean processing blood volume and the mean PBSC yield were 7407 ml and 2.16 x 10(6) CD34+ cells/kg, respectively. When CD34+ cells exceeded 0.3% of the peripheral WBC, more than 2.0 x 10(6) CD34+ cells/kg could be collected by a single apheresis. Eight patients underwent PBSC transplantation after high-dose chemotherapy. Hematopoietic recovery was achieved in a median period of 10 days. CONCLUSIONS (1) A single-arm, light-weight machine has sufficient capability to collect PBSC. (2) The percentage of CD34+ cells in the peripheral WBC is a good predictor of the CD34+ cell yield of the collection.