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.

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

Glutathione S-transferase mu (GSTM1) is mainly known as a detoxification enzyme but it has also been shown to be a negative regulator of apoptosis-related signaling cascades. Recently GSTM1 has been reported to be a significant risk factor for hematological relapse in childhood acute lymphoblastic leukemia, although the underlying mechanism remains largely unknown. Glucocorticoids play a crucial role in the treatment of childhood acute lymphoblastic leukemia, therefore we hypothesized that GSTM1 plays important roles in glucocorticoid-induced apoptotic pathways. To clarify the relationship between GSTM1 and drug resistance, GSTM1 was transfected into a T-acute lymphoblastic leukemia cell line, CCRF-CEM (CEM), and we established the GSTM1-expressing cell lines CEM/M1-4 and CEM/M1-9. Transduction of GSTM1 into CEM selectively decreased cellular sensitivity to dexamethasone in a manner that was independent of glutathione conjugation, but was due to apoptosis inhibition. Dexamethasone-induced p38-MAPK and Bim activation were concomitantly suppressed. Interestingly, nuclear factor kappa b (NF-kappaB) p50 activity was upregulated in GSTM1-expressing CEM. Inhibition of NF-kappaB by the pharmacological agent BAY11-7082 greatly enhanced the sensitivity of the GSTM1-expressing CEM to dexamethasone and was accompanied by an increase in Bim expression. Thus, we propose that GSTM1, a novel regulator of dexamethasone-induced apoptosis, causes dexamethasone resistance by suppression of Bim through dual mechanisms of both downregulation of p38-MAPK and upregulation of NF-kappaB p50.

Intracellular cytarabine triphosphate production correlates to deoxycytidine kinase/cytosolic 5'-nucleotidase II expression ratio in primary acute myeloid leukemia cells

Cytarabine (ara-C) is the key agent for treating acute myeloid leukemia (AML). After being transported into leukemic cells by human equilibrative nucleoside transporter 1 (hENT1), ara-C is phosphorylated to ara-C triphosphate (ara-CTP), an active metabolite, and then incorporated into DNA, thereby inhibiting DNA synthesis. Deoxycytidine kinase (dCK) and cytosolic 5'-nucleotidase II (cN-II) are associated with the production of ara-CTP. Because ara-C's cytotoxicity depends on ara-CTP production, parameters that are most related to ara-CTP formation would predict ara-C sensitivity and the clinical outcome of ara-C therapy. The present study focused on finding any correlation between the capacity to produce ara-CTP and ara-C-metabolizing factors. In vitro ara-CTP production, mRNA levels of hENT1, dCK, and cN-II, and ara-C sensitivity were evaluated in 34 blast samples from 33 leukemic patients including 26 with AML. A large degree of heterogeneity was seen in the capacity to produce ara-CTP and in mRNA levels of hENT1, dCK, and cN-II. Despite the lack of any association between each of the transcript levels and ara-CTP production, the ratio of dCK/cN-II transcript levels correlated significantly with the amount of ara-CTP among AML samples. The HL-60 cultured leukemia cell line and its three ara-C-resistant variants (HL-60/R1, HL-60/R2, HL-60/R3), which were 8-, 10-, and 500-fold more resistant than HL-60, respectively, were evaluated similarly. The dCK/cN-II ratio was again proportional to ara-CTP production and to ara-C sensitivity. The dCK/cN-II ratio may thus predict the capacity for ara-CTP production and ultimately, ara-C sensitivity in AML.

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.

Expression of ephrin in retinal neovascularization and iris rubeosis

We investigated expression of ephrin-B2 and Eph-B4 in the retinal tissues of six primate eyes with neovascularization and iris rubeosis secondary to laser-induced central retinal vein occlusion and in tissue from 10 human eyes with proliferative diabetic retinopathy. Two primate eyes with rubeosis and retinal neovascularization were enucleated 1, 2 and 4 weeks after the creation of central retinal vein occlusion. Antibodies were localized using the avidin-biotin reaction. In the primate eyes, ephrin-B2 was negative at I week and positive at 2 and 4 weeks in the rubeotic tissue, but was positive only at 2 weeks in the retinal neovascular membrane. Eph-B4 was negative in all the primate eye specimens. In the human tissue, ephrin-B2 was detected in two of the five eyes with rubeosis and three of the five eyes with retinal neovascularization. These data suggest that ephrin-B2 is a key regulator of neovascularization.

Protective effect of caspase inhibitor on intestinal integrity in experimental severe acute pancreatitis

BACKGROUND AND AIM

Endotoxin/bacterial translocation (E/BT) plays an important role in systemic complications in severe acute pancreatitis (SAP). The breakdown of intestinal integrity is considered to be implicated in E/BT. We recently demonstrated that accelerated apoptosis of intestinal mucosa may have a part in E/BT. On the other hand, caspase is believed to play a central role in apoptosis. The aim of this study was to investigate the efficacy of caspase inhibitor on intestinal integrity and E/BT in SAP.

METHODS

SAP was induced by retrograde injection of 3% sodium deoxycholate into the biliopancreatic ducts in rats. At the same time, polycaspase inhibitor (Z-VAD-fmk) was administered intraperitoneally. Caspase activation in the intestine was evaluated by immunohistochemical staining and Western blotting. Apoptosis of intestinal mucosa was detected by TdT-mediated dUTP-biotin nick end labeling staining and DNA fragmentation enzyme-linked immunosolvent assay. Intestinal permeability was assayed ex vivo by measuring the leaked amount of FITC-dextran. Blood endotoxin level, bacterial culture of the ascites and mesenteric lymph nodes, and 24-h mortality rate were evaluated.

RESULTS

Immunoreactivities for activated caspase-10, -9, and -3 were increased 2 h after induction of SAP. Apoptosis and permeability of ileum were significantly increased 6 h after induction of SAP. Caspase inhibitor significantly improved the increasing apoptosis and permeability. It did not prevent the bacterial translocation but improved the disorder of intestinal mucosa and elevation of blood endotoxin 18 h after induction of SAP. Moreover, caspase treatment significantly improved the 24-h mortality rate. Z-VAD-fmk indeed inhibited the caspase-3 activation in intestinal mucosa of SAP.

CONCLUSIONS

These results suggest that caspase activation has a key role in the accelerated apoptosis of intestinal epithelial cells in SAP and that breakdown of intestinal mucosa via accelerated apoptosis causes the increase in intestinal permeability following endotoxin translocation in SAP.

Ancestry and pharmacogenetics of antileukemic drug toxicity

Treatment-related toxicity in acute lymphoblastic leukemia (ALL) can not only be life threatening but may also affect relapse risk. In 240 patients, we determined whether toxicities were related to 16 polymorphisms in genes linked to the pharmacodynamics of ALL chemotherapy, adjusting for age, race (self-reported or via ancestry-informative markers), sex, and disease risk group (lower- vs higher-risk therapy). Toxicities (gastrointestinal, infectious, hepatic, and neurologic) were assessed in each treatment phase. During the induction phase, when drugs subject to the steroid/cytochrome P4503A pathway predominated, genotypes in that pathway were important: vitamin D receptor (odds ratio [OR], 6.85 [95% confidence interval [CI], 1.73-27.0]) and cytochrome P4503A5 (OR, 4.61 [95% CI, 1.11-19.2]) polymorphisms were related to gastrointestinal toxicity and infection, respectively. During the consolidation phase, when antifolates predominated, the reduced folate carrier polymorphism predicted gastrointestinal toxicity (OR, 10.4 [95% CI, 1.35-80.4]) as it also did during continuation (OR, 2.01 [95% CI, 1.06-4.11]). In all 3 treatment phases, a glucuronosyltransferase polymorphism predicted hyperbilirubinemia (P = .017, P < .001, and P < .001) and methotrexate clearance (P = .028), which was also independently associated with hyperbilirubinemia (P = .026). The genotype-phenotype associations were similar whether analyses were adjusted by self-reported race or ancestry-informative genetic markers. Germ-line polymorphisms are significant determinants of toxicity of antileukemic therapy.

A precise pharmacodynamic study showing the advantage of a marked reduction in cardiotoxicity in continuous infusion of doxorubicin

We have already shown that the antileukemic activity of daunorubicin that had been reported to be dependent on the area under the concentration - time curve (AUC) was actually peak concentration (Cmax) dependent. The antitumor activity of doxorubicin (DXR) has also been reported to be dependent on AUC, whereas its cumulative cardiotoxicity has been reported to be Cmax dependent. In this study, we evaluated whether the antileukemic and cardiotoxic effects of DXR were AUC or Cmax dependent, and compared their cytotoxic effects, utilizing the computer-controlled in vitro pharmacokinetic simulation system or a conventional culture system for a leukemic cell line and measuring the intracellular ATP amount or the proportion of beating cells for the cardiotoxicity. In leukemic cells, the cytotoxic rate decreased as the simulated infusion time or exposure time increased with the same AUC value in the simulation and conventional culture system (P < 0.05 and <0.01, respectively). The intracellular ATP and proportion of beating cells also increased with prolonged DXR exposure time with the same constant concentration - time product value (P < 0.05 and <0.0001, respectively) in heart cells. These results indicated that both the antileukemic effects and the cardiotoxicity were Cmax dependent. However, a comparison of the two showed that cardiotoxicity was more Cmax dependent than the antileukemic effect. These results suggested that the continuous infusion treatment schedule of DXR may have the clinical advantage of reducing cardiotoxicity more markedly than the antileukemic effect.

Pharmacogenetics of outcome in children with acute lymphoblastic leukemia

Acquired genetic characteristics of acute lymphoblastic leukemia (ALL) cells are used to individualize therapy, whereas germ line genetic characteristics generally are not. We determined whether ALL outcome was related to 16 genetic polymorphisms affecting the pharmacodynamics of antileukemic agents. Of 246 children, 116 were treated on the lower-risk (LR) and 130 on the higher-risk (HR) arms of a St Jude protocol. Patients in the HR group with the glutathione S-transferase (GSTM1) non-null genotype had greater risk of hematologic relapse (P = .03), which was further increased by the thymidylate synthetase (TYMS) 3/3 genotype (P = .03). These genotypes remained predictive in multivariate analyses (P < .001 and .003, respectively). No genotypes were predictive in the LR arm. Expression of these 2 genes in ALL blasts was lower in those with low-activity genotypes. For central nervous system relapse, among the HR group, the vitamin D receptor start site (P = .02) and intron 8 genotypes (P = .04) predisposed, whereas for LR patients the TYMS 3/3 genotype predisposed (P = .04). The GSTM1 non-null and TYMS 3/3 genotypes are plausibly linked to drug resistance. Polymorphisms interact to influence antileukemic outcome and represent determinants of response that can be used to optimize therapy.

Effect of FK506 eye drops on late and delayed-type responses in ocular allergy models

BACKGROUND

It is well-known that FK506 strongly inhibits cytokine production by T cells in vitro. However, less evidence is available from in vivo studies of ocular allergy.

OBJECTIVE

To study the anti-inflammatory effect of FK506 eye drops on late and delayed-type responses in several animal models of ocular allergy.

METHODS

Rats and guinea-pigs were sensitized with egg albumin (EA) in adjuvant and later challenged by topical EA application to their eyes to examine the late response. Biopsy specimens of conjunctiva were stained with haematoxylin-eosin or stained for T cells and eosinophils. In addition, rats, rabbits and guinea-pigs were sensitized with complete Freund's adjuvant and later challenged by injecting purified protein derivatives for the delayed-type response. Bulbar conjunctival oedema and hyperaemia were graded by score in rabbits, and Evans blue (EB) extravasation was measured in rats and guinea-pigs. FK506 (0.01-1%) and steroid (0.1%) eye drops were instilled in the eyes of animals several times, before and after challenge.

RESULTS

FK506 eye drops inhibited T cell and eosinophil infiltration in the late response and EB extravasation in the delayed-type response in rats. Also, they inhibited conjunctival oedema, hyperaemia and ocular mucus in the delayed-type response in rabbits. These effects were similar to those of steroid eye drops (betamethasone sodium phosphate, fluorometholone). FK506 eye drops also inhibited inflammatory cell infiltration, the loss of conjunctival epithelium and decrease of goblet cells in the late response as well as EB extravasation in the delayed-type response in guineapigs, a steroid-resistant species.

CONCLUSION

FK506 eye drops inhibit late and delayed-type responses in animal models of ocular allergy.

Effects of prednisone and genetic polymorphisms on etoposide disposition in children with acute lymphoblastic leukemia

Etoposide is a substrate for P-glycoprotein, CYP3A4, CYP3A5, and UGT1A1. Glucocorticoids modulate CYP3A and P-glycoprotein in preclinical models, but their effect on clinical etoposide disposition is unknown. We studied the pharmacokinetics of etoposide and its catechol metabolite in children with acute lymphoblastic leukemia, along with polymorphisms in CYP3A4, CYP3A5, MDR1, GSTP1, UGT1A1, and VDR. Plasma pharmacokinetics were assessed at day 29, after 1 month of prednisone (n = 102), and at week 54, without prednisone (n = 44). On day 29, etoposide clearance was higher (47.4 versus 29.2 mL/min/m2, P <.0001) than at week 54. The day 29 etoposide or catechol area under the curve (AUC) was correlated with neutropenia (P =.027 and P =.0008, respectively). The relationship between genotype and etoposide disposition differed by race and by prednisone use. The MDR1 exon 26 CC genotype predicted higher day 29 etoposide clearance (P =.002) for all patients, and the CYP3A5 AA and GSTP1 AA genotypes predicted lower clearance in blacks (P =.02 and.03, respectively). The UGT1A1 6/6, VDR intron 8 GG, and VDR Fok 1 CC genotypes predicted higher week 54 clearance in blacks (P =.039,.036, and.052, respectively). The UGT1A1 6/6 genotype predicted lower catechol AUC. Prednisone strongly induces etoposide clearance, genetic polymorphisms may predict the constitutive and induced clearance of etoposide, and the relationship between genotype and phenotype differs by race.

Pancreatic duct obstruction itself induces expression of alpha smooth muscle actin in pancreatic stellate cells

BACKGROUND

Pancreatic stellate cells (PSCs) are thought to be responsible for pancreatic fibrosis. Although fibrosis is a major characteristic of chronic pancreatitis (CP) induced by pancreatic duct obstruction, it is unclear whether pancreatic duct obstruction itself activates PSCs.

METHODS

To test the hypothesis that pancreatic duct obstruction activates PSCs, clinical and experimental analyses were performed using alpha smooth muscle actin (alpha-SMA) as a marker of their activation. In clinical analysis, surgical specimens from the patients with pancreatic cancer or cancer of the papilla Vater were classified into two groups with or without duct obstruction. alpha-SMA expression was examined on these specimens, and the difference between two groups was evaluated. In animal experiment, duct ligation-induced pancreatitis was developed in rats by ligating the secondary pancreatic duct in duodenal segment, and the expression of alpha-SMA was examined.

RESULTS

In clinical analysis, the specimens from the pancreas with duct obstruction (14 cases) expressed alpha-SMA significantly stronger than those from the pancreas without duct obstruction (7 cases). All specimens in the former expressed alpha-SMA, but 4 specimens from the latter did not at all (P < 0.05). In animal experiment, alpha-SMA expression was detected 7 days after the ligation and was increased on the 10th day.

CONCLUSIONS

We can assume that pancreatic duct obstruction itself activates PSCs. This mechanism may play roles in the development of CP from multiple origins.

Immunohistochemical study of surgically excised choroidal neovascular membranes

We carried out an immunohistochemical investigation of the choroidal neovascular membranes from 12 eyes surgically excised as a result of age-related macular degeneration (n = 6) or idiopathic choroidal neovascularization (n = 6). Immunohistochemical staining was performed with antibodies specific for basic transcriptional element binding protein-2, actin or smooth muscle cell 1. In all membranes, the endothelial cells and stromal components around the vessels were immunoreactive for expression of basic transcriptional element binding protein-2, while immunoreactive expression of actin and smooth muscle cell type 1 was found in the surrounding stromal cells. These results suggest that basic transcriptional element binding protein-2, a zinc finger transcription factor, may contribute to the establishment of the choroidal neovascularization observed in the pathogenesis of age-related macular degeneration and idiopathic choroidal neovascularization.

Intraperitoneal administration of oxygenated perfluorochemical inhibits bacterial translocation associated with severe acute pancreatitis

Bacterial translocation from gut has been assumed to be an infectious source in severe acute pancreatitis. The purpose of this study was to test the effect of intraperitoneal administration of oxygenated perfluorochemical on bacterial translocation associated with rat experimental acute necrotizing pancreatitis. Severe necrotizing pancreatitis was induced by retrograde injection of 3% sodium deoxycholate into the biliopancreatic ducts of male Wistar rats. Although mortality rate was not improved by the treatment, intraperitoneal administration of oxygenated perfluorochemical, perfulorodecalin reduced incidence of bacterial translocation to the mesenteric lymph nodes from 60% to 37% 12 hours after development of pancreatitis, and significantly reduced number of bacterial colonies detected after 24 hours. The treatment did not alter the villous height and crypt depth of the ileum. In this model for pancreatitis, however, accelerated apoptosis of the intestinal epithelium was detected histochemically by TUNEL staining and biochemically by DNA fragmentation ELISA, and the apoptotic changes were significantly suppressed by the treatment. These results indicate that intraperitoneal administration of oxygenated perfluorochemical inhibits apoptosis of intestinal epithelium and bacterial translocation induced in severe acute pancreatitis.

Homocysteine, pharmacogenetics, and neurotoxicity in children with leukemia

PURPOSE

Despite its clinical success, methotrexate (MTX) therapy is associated with toxicities such as seizures, the pathogenesis of which remains unclear. It has been suggested that hyperhomocysteinemia is caused by MTX and is responsible for its neurotoxic effects. The purposes of this study were to explore whether hyperhomocysteinemia was related to MTX administration and toxicity and whether homocysteine or MTX toxicity differed by methylenetetrahydrofolate reductase (MTHFR) or reduced folate carrier (RFC) genetic polymorphisms.

PATIENTS AND METHODS

We studied 53 children with newly diagnosed acute lymphoblastic leukemia who were consecutively treated on a single clinical protocol that included two courses of high-dose MTX (high-dose methotrexate [HDMTX]; 2.5 or 5.0 g/m2 per day) as consolidation therapy.

RESULTS

The study participants' median plasma homocysteine concentrations at 23 and 44 hours after HDMTX (9.00 micromol/L and 10.12 micromol/L, respectively) were greater than the concentrations immediately before HDMTX (5.77 micromol/L, P <.0001 for both comparisons). Seven days after HDMTX treatment, their plasma concentration returned to baseline. Nine patients experienced seizures, and five patients experienced thrombosis during the first 15 months of therapy, with a tendency for there to be higher plasma homocysteine in patients with seizures across all time points (P =.063) but not in patients with thrombosis (P =.59). We observed no significant differences in plasma or cerebrospinal fluid homocysteine levels or in toxicity based on the MTHFR 677C/T or RFC 80G/A genotypes.

CONCLUSION

We conclude that homocysteine was transiently elevated after HDMTX and may be related to seizure risk in children with leukemia.

Changes in hemodynamics and autonomic nervous activity in patients undergoing laparoscopic cholecystectomy: differences between the pneumoperitoneum and abdominal wall-lifting method

BACKGROUND AND STUDY AIMS

Intraoperative changes in circulatory hemodynamics and autonomic nervous activity were evaluated in 33 patients with cholelithiasis who underwent laparoscopic cholecystectomy.

PATIENTS AND METHODS

Of these patients, 18 were treated using a pneumoperitoneum (group G) and 15 using the abdominal wall-lifting method (group WL). Their ECG, blood pressure, arterial oxygen saturation, and expiratory carbon dioxide partial pressure were monitored. Autonomic nervous function was evaluated by spectral analysis of the heart rate.

RESULTS

Mean blood pressure increased significantly in group G during surgery, but did not vary in group WL during any stage of surgery. The high-frequency (HF) power, an index of parasympathetic activity, decreased significantly in group G after pneumoperitoneum. However, the HF power did not decrease significantly in group WL. The LF/HF ratio, an index of sympathetic activity, increased significantly in group G after pneumoperitoneum, but did not vary in group WL. In addition, the incidence of ventricular or supraventricular arrhythmias and the severity of the arrhythmias as determined by Lown's classification were higher in group G than in group WL. These findings suggest that intraoperative changes in autonomic nervous activity, due to increased intra-abdominal pressure, were smaller in patients undergoing laparoscopic cholecystectomy using the abdominal wall-lifting method than in those undergoing laparoscopic cholecystectomy using pneumoperitoneum. The results also demonstrated that hemodynamic changes were smaller in patients undergoing the abdominal wall-lifting method than in those undergoing pneumoperitoneum.

CONCLUSIONS

It was concluded that hemodynamics should be carefully monitored during pneumoperitoneum, and that the abdominal wall-lifting approach in laparoscopic cholecystectomy is a method worthy of consideration for elderly patients or those with cardiopulmonary complications.

Histological study of PIVKA-II expression in hepatocellular carcinoma and adenomatous hyperplasia

Although serum concentration of protein induced vitamin K absence or antagonist II (PIVKA-II) has been widely used for diagnosing hepatocellular carcinoma (HCC), little information is available concerning tissue PIVKA-II as an immunohistochemical marker for liver histology. In this study, we examined the expression of PIVKA-II in precancerous nodules (adenomatous hyperplasia) and various differentiation grades of HCC by immunohistochemical study using the monoclonal anti-PIVKA-II antibody (MU-3). We examined the relationship between tissue PIVKA-II staining and serum PIVKA-II level, tumor histology and tumor size. PIVKA-II was mainly detected in the cytoplasm of the HCC cells. The positive rates of PIVKA-II were as follows: adenomatous hyperplasia (AH), 0% (0/9); well-differentiated HCC, 65% (15/23); moderately differentiated HCC, 85% (22/26); poorly differentiated HCC, 54% (7/13). The expression of tissue PIVKA-II staining in moderately differentiated HCC was significantly higher than in well- or poorly differentiated HCC, whereas the serum PIVKA-II level in poorly differentiated HCC was higher than well- or moderately differentiated HCC. There was no relationship between the expression of PIVKA-II in cancer tissues and serum levels of PIVKA-II. Immunohistochemical studies revealed that PIVKA-II was expressed even in small-sized or well-differentiated HCC cells, but expression was not detected in AH. It was concluded that PIVKA-II is a useful immunohistochemical marker, even in small-sized or well-differentiated HCC.

Characterization of zebrafish caspase-3 and induction of apoptosis through ceramide generation in fish fathead minnow tailbud cells and zebrafish embryo

Caspase-3 was cloned from zebrafish embryos and its properties were characterized to identify the biological implications of caspase in embryogenesis and apoptosis in zebrafish, which is a model organism in vertebrate developmental biology and genetics. The predicted amino acid sequence, totalling 282 amino acid residues, consisted of the prodomain and large and small subunits. Phylogenetic analysis showed that the cloned zebrafish caspase was a member of the caspase-3 subfamily with approx. 60% identity with caspase-3 from Xenopus, chicken and mammals. In addition, recombinant zebrafish caspase hydrolysed acetyl-Asp-Glu-Val-Asp-4-methyl-coumaryl-7-amide, and exhibited similar substrate specificity to the mammalian caspase-3 subfamily. Therefore this caspase was designated zebrafish caspase-3. Overexpression of zebrafish caspase-3 induced apoptosis and increased ceramide levels in fish fathead minnow tailbud cells and zebrafish embryos. Both ceramide generation and apoptosis induction were inhibited by treatment with a caspase inhibitor, benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone. Moreover, zebrafish caspase-3 mRNA was present in early embryos up to the 1000-cell stage as a maternal factor, and was then expressed throughout the body after the gastrula stage by zygotic expression. These findings indicate that the isolated caspase-3 plays an important role in the induction of ceramide generation as well as apoptosis in fish cells and the zebrafish embryo, and suggest that caspase-3 functions as a modulator of the pro-apoptotic signal in development.

Serous retinal detachment in patients under systemic corticosteroid treatment

PURPOSE

To understand the pathophysiology of central serous chorioretinopathy or bullous retinal detachment in patients under systemic corticosteroid treatment. Little is understood about the mechanism of the development of serous retinal detachment.

METHODS

Three patients who had developed central serous chorioretinopathy or bullous retinal detachment during systemic corticosteroid administration were examined by fluorescein angiography and indocyanine green angiography.

RESULTS

Indocyanine green angiography revealed dilated choroidal veins, delayed choroidal filling, intrachoroidal hyperfluorescence, and patchy hypofluorescence at or near the sites of dye leakage examined by fluorescein angiography.

CONCLUSIONS

The primary change caused by central serous chorioretinopathy is thought to occur in the choroid, followed by the breakdown of the outer blood-retinal barrier in the pigment epithelium, resulting in the development of serous retinal detachment.

A specific interaction between the telomeric protein Pin2/TRF1 and the mitotic spindle

Pin2/TRF1 was independently identified as a telomeric DNA binding protein (TRF1) [1] and as a protein (Pin2) that can bind the mitotic kinase NIMA and suppress its ability to induce mitotic catastrophe [2, 3]. Pin2/TRF1 has been shown to bind telomeric DNA as a dimer [3-7] and to negatively regulate telomere length [8-11]. Interestingly, Pin2/TRF1 levels are regulated during the cell cycle, being increased in late G2 and mitosis and degraded as cells exit from mitosis [3]. Furthermore, overexpression of Pin2/TRF1 induces mitotic entry and then apoptosis [12]. This Pin2/TRF1 activity can be significantly potentiated by the microtubule-disrupting agent nocodazole [12] but is suppressed by phosphorylation of Pin2/TRF1 by ATM; this negative regulation is important for preventing apoptosis upon DNA damage [13]. These results suggest a role for Pin2/TRF1 in mitosis. However, nothing is known about how Pin2/TRF1 is involved in mitotic progression. Here, we describe a surprising physical interaction between Pin2/TRF1 and microtubules in a cell cycle-specific manner. Both expressed and endogenous Pin2/TRF1 proteins were localized to the mitotic spindle during mitosis. Furthermore, Pin2/TRF1 directly bound microtubules via its C-terminal domain. Moreover, Pin2/TRF1 also promoted microtubule polymerization in vitro. These results demonstrate for the first time a specific interaction between Pin2/TRF1 and microtubules in a mitosis-specific manner, and they suggest a new role for Pin2/TRF1 in modulating the function of microtubules during mitosis.

Inflammatory cytokines in vitreous fluid and serum of patients with diabetic vitreoretinopathy

To determine whether inflammatory cytokines are increased in proliferative diabetic retinopathy. We measured concentrations of interleukin-6, 8 (IL-6, 8) and tumor necrosis factor (TNF)-alpha by enzyme-linked immunosorbent assay (ELISA) in vitreous and serum from 47 patients with proliferative diabetic retinopathy and 21 patients with vitreous noninflammatory retinopathies. Vitreous concentration of IL-6 were 64.7+/-12.8 pg/ml in proliferative diabetic retinopathy, much greater (P<.005) than in noninflammatory retinopathy (2.8+/-4.5 pg/ml). Amounts of IL-8 in vitreous fluid also were greater in proliferative retinopathy than in noninflammatory retinopathy (34.0+/-11.5 vs. 6.1+/-2.0 pg/ml, P<.005). Concentrations of TNF-alpha in vitreous fluid were not statistically different in proliferative retinopathy from those in noninflammatory retinopathy. In sera, concentrations of IL-6 and IL-8 were not different between proliferative and noninflammatory retinopathy. However, serum TNF-alpha was much greater in proliferative retinopathy than in noninflammatory retinopathy (0.81+/-0.72 vs. 0.09+/-0.00 pg/ml, P<.001). Elevated TNF-alpha in serum then may be diagnostically useful in proliferative diabetic retinopathy. And inflammatory cytokines in vitreous may be pathogenically important in this concentration.

Close correlation of 1-beta-D-arabinofuranosylcytosine 5'-triphosphate, an intracellular active metabolite, to the therapeutic efficacy of N(4)-behenoyl-1-beta-D-arabinofuranosylcytosine therapy for acute myelogenous leukemia

N(4)-Behenoyl-1-beta-D-arabinofuranosylcytosine (BHAC), a prodrug of 1-beta-D-arabinofuranosylcytosine, 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-beta-D-arabinofuranosylcytosine 5'-triphosphate (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 / m(2)) in combination remission induction therapy. ara-CTP could be monitored at levels under 1 mM. 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 time, 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.

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

1-beta-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-beta-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 myelogenous leukemia patients receiving low- or conventional-dose ara-C [subcutaneous ara-C administration (10 mg / m(2) ) (3 patients), continuous ara-C infusion (20 or 70 mg / m(2) / 24 h) (7 patients), 2-h ara-C infusion (70 mg / m(2) ) (4 patients), and 2-h infusion of N(4)-behenoyl-1-beta-D-arabinofuranosylcytosine, a deaminase-resistant ara-C derivative (70 mg / m(2) ) (6 patients)]. Ara-CTP could be determined at levels under 1 microM. 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 N(4)-behenoyl-1-beta-D-arabinofuranosylcytosine 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.