中川 義仁

Background/Aims: This study was performed to examine the changes in rapid turnover proteins (RTPs), such as retinol-binding protein, transthyretin and transferrin, which are known nutritional parameters, during the perioperative period for digestive system operations. Methodology: The study was performed with 62 subjects who underwent elective surgery of the digestive system. The RTP measurements were performed approx. seven times for each subject (approx. 20 times in total) from the preoperative period to the 14(th) postoperative day. For 20 subjects who exhibited no recurrence of a malignant tumor, additional measurements were performed 6 to 12 months after the operation. RTPs were measured more than 1,400 times in total for all subjects. Results: The three types of RTPs all exhibited similar changes, but the largest change was observed for retinol-binding protein. The changes in RTPs were significantly larger than those for albumin. RTP levels were lowest on the 3(nd) postoperative day and gradually increased thereafter. The RTP levels recovered to approx. 80% of the preoperative values on the 14(th) postoperative day. In the measurements performed 6 to 12 months after the operation, the levels recovered to 90% or higher of the preoperative values. No significant differences were observed between the cases utilizing different operation methods. The administration of fresh frozen plasma had no impact on the postoperative changes. No correlation was observed between the calories obtained by oral intake during the period from the 5(th) to 10(th) postoperative days and the changes in RTPs. Conclusion: The study results suggested that changes in RTPs would not affected by the calories obtained by oral intake during the early postoperative days. In patients who returned to their daily life after an invasive surgery or reconstruction of the digestive tract, RTP levels were restored to the preoperative values 6 to 12 months after the operation.

In this article, the effects of allicin, a biological active compound of garlic, on HL60 and U937 cell lines were examined. Allicin induced growth inhibition and elicited apoptotic events such as blebbing, mitochondrial membrane depolarization, cytochrome c release into the cytosol, activation of caspase 9 and caspase 3 and DNA fragmentation. Pretreatment of HL60 cells with cyclosporine A, an inhibitor of the mitochondrial permeability transition pore (mPTP), inhibited allicin-treated cell death. HL60 cell survival after 1 h pretreatment with cyclosporine A, followed by 16 h in presence of allicin (5 mu M) was similar to 80% compared to allicin treatment alone (similar to 50%). Also M-acetyl cysteine, a reduced glutathione (GSH) precursor, prevented cell death. The effects of cyclosporine A and N-acetyl cysteine suggest the involvement of mPTP and intracellular GSH level in the cytotoxicity. Indeed, allicin depleted GSH in the cytosol and mitochondria, and buthionine sulfoximine, a specific inhibitor of GSH synthesis, significantly augmented allicin-induced apoptosis. In HL60 cells treated with allicin (5 mu M, 30 min) the redox state for 2GSH/oxidized glutathione shifted from E-GSH -240 to -170 mV. The same shift was observed in U937 cells treated with allicin at a higher concentration for a longer period of incubation (20 mu M, 2 h). The apoptotic events induced by various concentrations of allicin correlate to intracellular GSH levels in the two cell types tested (HL60: 3.7 nmol/10(6) cells; U937: 7.7 nmol/ 106 cells). The emerging mechanistic basis for the antiproliferative function of allicin, therefore, involves the activation of the mitochondrial apoptotic pathway by GSH depletion and by changes in the intracellular redox status. (C) 2008 Elsevier Inc. All rights reserved.

Mangosteen, Garcinia mangostana Linn, is a tree found in South East Asia, and its pericarps have been used as traditional medicine. Phytochemical studies have shown that they contain a variety of secondary metabolites, such as oxygenated and prenylated xanthones. Recent studies revealed that these xanthones exhibited a variety of biological activities containing anti-inflammatory, anti-bacterial, and anti-cancer effects. We previously investigated the anti-proliferative effects of four prenylated xanthones from the pericarps; alpha-mangostin, beta-mangostin, gamma-mangostin, and methoxy-beta-mangostin in various human cancer cells. These xanthones are different in the number of hydroxyl and methoxy groups. Except for methoxy-beta-mangostin, the other three xanthones strongly inhibited cell growth at low concentrations from 5 to 20 mu M in human colon cancer DLD-1 cells. Our recent study focused on the mechanism of alpha-mangostin-induced growth inhibition in DLD-1 cells. It was shown that the anti-proliferative effects of the xanthones were associated with cell-cycle arrest by affecting the expression of cyclins, cdc2, and p27; G1 arrest by alpha-mangostin and beta-mangostin, and S arrest by gamma-mangostin. alpha-Mangostin found to induce apoptosis through the activation of intrinsic pathway following the down-regulation of signaling cascades involving MAP kinases and the serine/threonine kinase Akt. Synergistic effects by the combined treatment of alpha-mangostin and anti-cancer drug 5-FU was to be noted. a-Mangostin was found to have a cancer preventive effect in rat carcinogenesis bioassay and the extract from pericarps, which contains mainly a-mangostin and mangostin, exhibited an enhancement of NK cell activity in a mouse model. These findings could provide a relevant basis for the development of xanthones as an agent for cancer prevention and the combination therapy with anti-cancer drugs.

Recently, it has been found that inappropriate expression of microRNAs (miRNAs) is strongly associated with carcinogenesis. In this study, we demonstrated that the expression of miRNAs (miRs) -143 and -145, the levels of which were previously shown to be reduced in colon cancers and various kinds of established cancer cell lines, was also decreased in most of the B-cell malignancies examined, including chronic lymphocytic leukemias (CLL), B-cell lymphomas, Epstein-Barr virus (EBV)-transformed B-cell lines, and Burkitt lymphoma cell lines. All samples from 13CLL patients and eight of nine B-cell lymphoma ones tested exhibited an extremely low expression of miRs-143 and -145. The expression levels of miRs-143 and -145 were consistently low in human Burkitt lymphoma cell lines and were inversely associated with the cell proliferation observed in the EBV-transformed B-cell lines. Moreover, the introduction of either precursor or mature miR-143 and -145 into Raji cells resulted in a significant growth inhibition that occurred in a dose-dependent manner and the target gene of miRNA-143 was determined to be ERK5, as previously reported in human colon cancer DLD-1 cells. Taken together, th

Recently, it has been found that inappropriate expression of microRNAs (miRNAs) is strongly associated with carcinogenesis. In this study, we demonstrated that the expression of miRNAs (miRs) -143 and -145, the levels of which were previously shown to be reduced in colon cancers and various kinds of established cancer cell lines, was also decreased in most of the B-cell malignancies examined, including chronic lymphocytic leukemias (CLL), B-cell lymphomas, Epstein-Barr virus (EBV)-transformed B-cell lines, and Burkitt lymphoma cell lines. All samples from 13 CLL patients and eight of nine B-cell lymphoma ones tested exhibited an extremely low expression of miRs-143 and -145. The expression levels of miRs-143 and -145 were consistently low in human Burkitt lymphoma cell lines and were inversely associated with the cell proliferation observed in the EBV-transformed B-cell lines. Moreover, the introduction of either precursor or mature miR-143 and -145 into Raji cells resulted in a significant growth inhibition that occurred in a dose-dependent manner and the target gene of miRNA-143 was determined to be ERK5, as previously reported in human colon cancer DLD-1 cells. Taken together, these findings suggest that miRs-143 and -145 may be useful as biomarkers that differentiate B-cell malignant cells from normal cells and contribute to carcinogenesis in B-cell malignancies by a newly defined mechanism. © 2007 Japanese Cancer Association.

alpha-Mangostin, a xanthone from the pericarps of mangosteen (Garcinia mangostana Linn.), was evaluated for in vitro cytotoxicity against human colon cancer DLD-1 cells. The number of viable cells was consistently decreased by the treatment with a-mangostin at more than 20 mu M. The cytotoxic effect of 20 mu M alpha-mangostin was found to be mainly due to apoptosis, as indicated by morphological findings. Western blotting, the results of an apoptosis inhibition assay using caspase inhibitors, and the examination of caspase activity did not demonstrate the activation of any of the caspases tested. However, endonuclease-G released from mitochondria with the decreased mitochondrial membrane potential was shown. The levels of phospho-Erk1/2 were increased in the early phase until I h after the start of treatment and thereafter decreased, and increased again in the late phase. On the other hand, the level of phospho-Akt was sharply reduced with the process of apoptosis after 6 It of treatment. Interestingly, the level of microRNA- 143, which negatively regulates Erk5 at translation, gradually increased until 24 It following the start of treatment. We also examined the synergistic growth suppression in DLD-1 cells by the combined treatment of the cells with a-mangostin and 5-FU which is one of the most effective chemotherapeutic agents for colorectal adenocarcinoma. The co-treatment with alpha-mangostin and 5-FU, both at 2.5 mu M, augmented growth inhibition compared with the treatment with 5 VM of a-mangostin or 5 mu M 5-FU alone. These findings indicate unique mechanisms of alpha-mangostin- induced apoptosis and its action as an effective chemosensitizer. (C) 2007 Elsevier Ltd. All rights reserved.

MicroRNAs (miRNAs) are endogenous, small non-coding RNAs (20-22 nucleotides) that negatively regulate gene expression at the translational level by base pairing to the 30 untranslated region of target messenger RNAs. More than 400 miRNAs have been identified in humans and are evolutionally conserved from plants to animals. It has been revealed that miRNAs regulate various biological processes, such as development, cell differentiation, cell proliferation, and cell death. It is predicted that 30% of protein-encoding genes are regulated by miRNAs. Inappropriate expression of miRNAs has been found in cancer. Especially, the expression level of miRNAs that act like anti-oncogenes is frequently reduced in cancers because of chromosome aberrations. In addition, since the processing of miRNAs has been characterized to be enzymatic in nature, the expression levels of miRNAs are closely associated with the activity and levels of such enzymes. In this review, we discuss recent remarkable advances in miRNA biogenesis, bio-networking involving miRNAs, and their roles in carcinogenesis. Further, we discuss the expression of miRNA-143 and -145 in colon cancer and their roles in carcinogenesis. The available data suggest that miRNAs would be potentially useful as diagnostic and therapeutic tools.

Magnolol has been reported to have an inhibitory effect on tumor invasion in vitro and in vivo. In this study, we found that treatment with 30 mu m magnolol exhibited growth inhibition partly by inducing apoptosis in cultured human leukemia U937 cells and that the apoptosis was induced via the sequential ordering of molecular events; 1) a transient decrease of phosphorylated extracelluar signal-requlated kinase (ERK), 2) translocation of apoptosis inducing factor (AIF) from mitochondria to cytosol concurrent with a decreased membrane potential, and 3) downregulation of bcl-2 protein. Pretreatment of the cells with a pan-caspase inhibitor Z-Val-Ala-Asp-fluoromethyl ketone (Z-VAD-FMK) did not prevent the apoptosis induced by magnolol. These findings indicated that the above-mentioned sequence of intracellular signaling events led to apoptosis in magnolol-treated U937 cells, which was caspase-independent.

MicroRNAs (miRNAs) are endogenously expressed RNAs 18-24 nucleotides in length that regulate gene expression through translational repression by binding to a target mRNA. It is thought that the expression level of miRNAs, which act like antioncogenes, is frequently reduced in cancers because of chromosome deletion and epigenetic changes. Since the processing of miRNAs has been characterized to be enzymatic in nature, the expression levels of miRNAs are closely associated with the activity and levels of such enzymes. Here, we found that miRNA 143 and 145 expression levels were extremely reduced in colon cancer cells and commonly in the other kinds of cancer cells tested. The transfection of each precursor miRNA into the cells demonstrated a significant growth inhibition in human colon cancer DLD-1 and SW480 cells, and ERK5 was determined to be the target gene of miRNA 143. Since the presence of genomic loci of the miRNAs was confirmed by PCR in the cell lines and the precursor miRNAs exhibited a growth inhibitory effect in DLD-1 and SW480 cells, the early processes such as transcription and enzymatic modification from primary miRNAs to precursor miRNAs seemed to be commonly disturbed. These findings indicate that the miRNAs 143 and 145 could become good tumor markers and provide an important clue in the study of the mechanism of oncogenesis involving miRNAs.

rck/p54, a DEAD-box RNA helicase, is closely associated with the basic modification of RNA molecules in the process of mRNA transport, RNA decay, and translation initiation. In the current study, Western blot analysis revealed that rck/p54 protein was ubiquitously expressed in mouse tissues, Interestingly, three different-sized rck/p14 proteins were detected by antibodies against mouse rck/p54, and these products were differentially expressed in the tissues. An immunohistochemical study revealed that rck/p54 was strongly expressed in basal cells of the crypt in the gastrointestinal tract and in neuronal bodies of the, cerebral cortex, and was localized in epithelial cells of the convoluted tubules of the kidneys, suggesting that the heterogeneous rck/p54 may play pivotal roles in cells committed to become specialized in these tissues.

Fragile histidine triad (FHIT) gene is involved in the deletions at the 3p14.2 region in various cancers. We investigated the role of Fhit protein in cell growth by examining the signaling pathway affected by Fhit. We used 3 human colon cancer cell lines, SW480, DLD-1 and COLO201, in the study. SW480 cells, in which the expression of Fhit is completely absent, were transfected with pIRES1neo vector (SW/IRES cells), wild-type FHIT vector (SW/FHIT cells) or mt-FHIT (codon 96, His changed to Asn) vector (SW/mt-FHIT cells). The growth of SW/FHIT or SW/mt-FHIT cells was suppressed in comparison with that of parent or SWIRES cells. Especially, the growth of SW/FHIT cells was considerably suppressed. on the other hand, the silencing of FHIT by an siRNA for it in SW/FHIT or DLD-1 cells harboring Fhit demonstrated that the growth of FHIT siRNA-treated cells was significantly enhanced in comparison with that of the vector control or nonspecific siRNA control. Thus, we found that Fhit negatively contributed to cell growth in the colon cancer cell lines. Moreover, SW/FHIT cells exhibited a higher sensitivity to oxidative stress evoked by inhibitors of mitochondrial electron transport or proteasomes compared with any of the control transfectants. The base line amount of phospho-I kappa B-alpha (p-I kappa B-alpha) was reduced in SW/FHIT cells compared with that in the other transfectants. On the contrary, the FHIT siRNA-treated SW/FHIT and DLD-1 cells exhibited an elevated p-I kappa B-alpha level in an RNAi experiment on FHIT. Perturbation of nuclear factor (NF)-kappa B signaling was strongly suggested by the fact that the wild-type Fhit expressants of SW480 cells tended to be sensitive to sulfasarazine or parthenolide, which are inhibitors of NF-kappa B. The time course of the level Of I kappa B kinase (IKK) complex (IKK alpha/beta, phospho-IKK alpha/beta and IKK gamma) after the treatment with TNF-alpha was similar between the transfectants. Although p-I kappa B-alpha and phospho-NF-kappa B p65 (p-NF-kappa B) in SW/FHIT cells responded to TNF-alpha as those in other transfectants, the increase in the levels Of P-I kappa B-alpha and p-NF-kappa B after a 5-min treatment was less in SW/FHIT cells than in the other transfectants. These results altogether suggest that Fhit functions as an anti-oncoprotein by inhibiting the phosphorylation Of I kappa B-alpha and thereby blocking NF-kappa B signaling. (c) 2006 Elsevier Inc. All rights reserved.

Understanding the control of gene expression in cancer cells requires defining the molecular and cellular basis of RNA metabolism compared with that in steady-state normal cells. Previously, we reported evidence that human RNA structure-modifying unwindase rck/p54, a member of the DEAD-box family, was highly expressed in most of the malignant cell lines tested and that this expression was linked to malignant transformation. Here, we show that rck/p54 positively affects cell growth, probably by modulating the gene expression at the translational level in cultured cells. In cell growth and differentiation induced by external stimuli, the level of rck/p54 expression was up-regulated during cell proliferation and down-regulated during differentiation. The down-regulation of rck/p54 in HeLa cells by RNAi induced cell growth inhibition through cell cycle arrest at S phase. Immunoprecipitation using anti-rck/p54 antibody in HeLa cells demonstrated the co-precipitation of rck/p54 with eIF4E, which is well-known to bind to the 5'cap-structure, resulting in initiation of translation. These data suggest that rck/p54 contributes to cell growth possibly by modulating translation-initiation control of the genes involved in the cell proliferation, which is a newly defined mechanism leading to carcinogenesis.

Fifty-six stilbenoids isolated from the families of Welwitschiaceae and Gnetaceae were screened for growth inhibitory activity against HL60 cells, and two compounds (gnemonol G and gnetin 1) among them exhibited a strong activity with IC50 of 10.0 ym and 12.2 mu m at 48 h incubation, respectively. The growth suppression by gnemonol G and gnetin I was found to be in part due to apoptosis which was assessed by morphological findings such as nuclear condensation and fragmentation, and DNA ladder formation in human leukemia HL60 cells.

MicroRNAs (miRNAs) are endogenously expressed RNAs, 18-25 nucleotides in length, that repress protein translation through binding to target mRNAs. miRNAs have been implicated in many cellular processes including cell proliferation, differentiation, and death. Recently, let-7 miRNAs were found to regulate human RAS oncogene expression and to be often down-regulated in human lung tumors. In this study, we examined the expression of let-7 miRNAs in human colon cancer tumors and cell lines, with the result that 2 of 6 cases and 1 of 3 cell lines showed reduced expression of let-7. When let-7 low-expressing DLD-1 human colon cancer cells were transfected with let-7a-1 precursor miRNA, which is located at chromosome 9q22.3, the cells underwent significant growth suppression. At that time, the levels of RAS and c-myc proteins were lowered after the transfection, whereas the levels of both of their mRNAs remained almost unchanged. These findings suggest the involvement of let-7 miRNA in the growth of colon cancer cells. Thus, miRNAs might provide a basis for novel RNA anti-cancer agents.

Although most of pharmacological therapies for cancer utilize the apoptotic machinery of the cells, the available anti-cancer drugs are limited due to the ability of prostate cancer cells to escape from the anti-cancer drug-induced apoptosis. A human prostate cancer cell line PC3 is resistant to camptothecin (CPT). To elucidate the mechanism of this resistance, we have examined the involvement of sphingosine kinase (SPHK) and sphingosine 1-phosphate (S1P) receptor in CPT-resistant PC3 and -sensitive LNCaP cells. PC3 cells exhibited higher activity accompanied with higher expression levels of protein and mRNA of SPHK1 and also elevated expression of S1P receptors, S1P, and S1P(3), as compared with those of LNCaP cells. The knockdown of SPHK1 by small interfering RNA and inhibition of S1P receptor signaling by pertussis toxin in PC3 cells induced significant inhibition of cell growth, Suggesting implication of SPHK1 and S1P receptors in cell proliferation in PC3 cells. Furthermore, the treatment of PC3 cells with CPT was found to induce up-regulation of the SPHK1/ SIP signaling by induction of both SPHK1 enzyme and SIP1/SIP3 receptors. These findings strongly suggest that high expression and up-regulation of SPHK1 and S1P receptors protect PC3 cells from the apoptosis induced by CPT. (c) 2006 Elsevier Inc. All rights reserved.

Melanogenesis is a principal parameter of differentiation in melanocytes and melanoma cells. Our recent study has demonstrated that phospholipase D1 (PLD1) regulates the melanogenic signaling through modulating the expression of tyrosinase, the rate-limiting step enzyme in the melanin biosynthesis. The current study was designed to gain more insight into the involvement of PLD1 in the regulation of melanogenesis. To investigate the role of PLD1, we examined the effect of knockdown of endogenous PLD1 by small interference RNA (siRNA) on melanogenesis in 1316 melanoma cells. It was shown that the melanin synthesis was induced in PLD1-knockdowned cells, and also that the level of melanin synthesis was well correlated with increases in expression level of tyrosinase and its related proteins (Tyrp1 and Dct). Furthermore, the reduction of expression levels of PLD1 by siRNA transfection was accompanied by diminution of ribosomal S6 kinase 1 (S66K1) phosphorylation. The activity of mammalian target of rapamycin (mTOR) is essential for phosphorylation of S6K1 and the treatment malanoma cells with rapamycin, a potent inhibitor of mTOR effectively induced melanogenesis. The results obtained here provide possible evidence that PLD1 exerts a negative regulatory role in the melanogenic process through mTOR/S6K1 signaling.

Six main sesquiterpene lactones (germacranolides) from Calea urticifolia were evaluated for in vitro cytotoxicity against human tumor cell lines HL60 and SW480 cells. Among them, arucanolide and parthenolide displayed marked cytotoxicity against both cell lines. Arucanolide exhibited a low IC50 in HL60 cells. The cytotoxic activity of arucanolide was observed at lower concentrations compared to that of parthenolide, which has been reported to be a typical and simple germacranolide. The activity was found to be mainly due to apoptosis that was assessed by morphological findings, DNA ladder formation (24-36h), and flow cytometric analysis in HL60 cells. Western blotting and an apoptosis inhibition assay using caspase inhibitors did not demonstrate the activation of any caspases tested. However, the mitochondrial membrane potential of HL60 cells was lost after 24-h treatment with arucanolide, and concurrently apoptosis-inducing factor (AIF) released from mitochondria was detected by Western blot analysis. The inactivation of nuclear factor-kappaB, which has been commonly shown in parthenolide-induced apoptosis, did not occur in arucanolide-induced apoptosis. Taken together, the findings presented here indicate that arucanolide induced marked apoptosis in HL60 cells mainly by dissipating mitochondrial membrane potential, which would trigger AIF-induced apoptosis.

Approaches to protection against neurodegenerative diseases, in which oxidative stress and inflammation are implicated, should be based on the current concept on the etiology of these diseases. Recently, a new therapeutic strategy has been proposed to protect neurons from cell death by attenuating the apoptotic signal transduction. Lignin, a durable aromatic network polymer second to cellulose in abundance, was able to be converted into highly active lignophenol derivatives with antioxidant activity by using our newly developed phase-separation technique. These lignophenol derivatives were found to show the potent neuroprotective activity against oxidative stress. Among the compounds examined, a lignocresol derivative from bamboo (lig-8) exhibited the most potent neuroprotective activity against hydrogen peroxide (H2O2)-induced apoptosis in human neuroblastoma cell line SH-SY5Y by preventing the caspase-3 activation via either caspase-8 or caspase-9. Furthermore, it was found that lig-8 exerted the antiapoptotic effect by inhibiting dissipation of the mitochondrial membrane permeability transition induced by H2O2 or by the peripheral benzodiazepin receptor ligand PK11195. Lig-8 was also shown to be potent in the antioxidant activity in the cells exposed to H2O2, as assessed by flow cytometry using 5-(and -6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate and in vitro reactive oxygen species-scavenging potency. These data suggest that lig-8 is a promising neuroprotector, which affects the signaling pathway of neuronal cell death and that it would be of benefit to delay the progress of neurodegenerative diseases. (C) 2004 Elsevier Ltd. All rights reserved.

Hepatitis C virus (HCV) infection is the most common cause of chronic hepatitis, which frequently progresses to hepatocellular carcinoma. The pathogenesis of its persistent infection and tumour progression has not been fully characterized yet. The RCK gene was previously cloned at the breakpoint of the t(11;14)(q23;q32) chromosome translocation observed in human B-cell lymphoma cell line RC-K8. The RCK protein, rck/p54, which is a 54-kDacytoplasmic protein belonging to the DEAD box/RNA helicase family, is considered to facilitate the translation of mRNA(s) of genes for cell proliferation and malignant transformation not only in B-cell lymphomas having the t(11;14) translocation but also in other solid tumours. The aim of this work was to examine the involvement of rck/p54 in carcinogenesis of hepatocellular carcinoma from HCV-related chronic hepatitis. We examined the expression of rck/p54 in 29 cases of HCV-related chronic hepatitis and eight cases of hepatocellular carcinoma by immunohistochemistry and Western blot analysis. Twenty-six of 29 cases with HCV-related chronic hepatitis and all cases with hepatocellular carcinoma tested overexpressed rck/p54 protein. The expression of

The role of mitochondrial permeability transition (PT) in apoptosis induced by an endogenous neurotoxin, N -methyl(R )salsolinol [N M(R )Sal], was studied by use of dopaminergic neuroblastoma SH-SY5Y cells. N M(R )Sal reduced mitochondrial membrane potential, DeltaPsim, in the early phase of apoptosis, which was not suppressed by a pan-caspase inhibitor, but was antagonized by Bcl-2 and cyclosporin A, suggesting the involvement of the PT in N M(R )Sal-induced loss of DeltaPsim. N M(R )Sal-induced apoptosis was completely inhibited not only by Bcl-2 and a pan-caspase inhibitor, but also by cyclosporin A, suggesting the essential role of the PT in N M(R )Sal-induced apoptosis. In mitochondria isolated from rat liver, N M(R )Sal induced swelling and reduced DeltaPsim, which was inhibited by cyclosporin A and Bcl-2 overexpression. These results indicate that N M(R )Sal induced the PT by direct action on the mitochondria. Rasagiline, N -propargyl-1(R )-aminoindan, which is a now under a clinical trial for Parkinson's disease, suppressed the DeltaPsim reduction, release of cytochrome c, and apoptosis induced by N M(R )Sal in SH-SY5Y cells. Rasagiline also inhibited the N M(R )Sal-induced loss of DeltaPsim and swelling in the isolated mitochondria, proving that rasagiline directly targets the mitochondria also. Altogether, mitochondrial PT plays a key role both in N M(R )Sal-induced cell death and the neuroprotective effect of rasagiline.

We have investigated to determine the source of ceramide produced during the genotoxic apoptosis induced by the anti-cancer drug, camptothecin (CPT), in human prostate cancer LNCaP cells by measuring the activities of acid and neutral sphingomyelinases (SMase) and by using fumonisinB(1) (FB1), the inhibitor of ceramide synthase involving de novo synthesis of ceramide. In contrast to time-dependent elevation of intracellular ceramide level after CPT-treatment, the activities of both SMases were not increased but rather decreased. Instead, pretreatment for 3 h with FB1 (100 muM), an inhibitor of ceramide synthase, almost completely abrogated ceramide accumulation observed in cells exposed to CPT for 18 h. These results indicate that ceramide is produced via de novo pathway but not via sphingomyelin hydrolysis pathway. Furthermore, it is to be noted that the pretreatment with FB1 did not affect the CPT-induced apoptosis as assessed by DNA ladder formation, Hoechst 33342 staining, flow cytometry, and mitochondrial potential thereby leading us to propose that ceramide accumulation is independent of apoptosis in this system. (C) 2002 Elsevier Science (USA). All rights reserved.

Background: We examined a technique for detecting point mutations of K-ras codon 12 in stool samples using one-step polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) analysis, in order to determine whether it could be used to screen for colorectal cancer. Methods: DNA was extracted from 200-mg stool specimens of 5 healthy controls and 31 colorectal cancer patients. A 107-base-pair fragment of exon 1 of K-ras was amplified by PCR using mismatched primers. PCR products were digested with Bst NI and analyzed by gel electrophoresis followed by silver staining. Specificity of one-step PCR/RFLP was examined by using synthetic oligonucleotides. The detection limit of K-ras codon 12 mutations was determined by using SW480 and HT29 cells. Results: The K-ras gene was successfully amplified from all healthy controls and colorectal cancer patients studied. Mutations of K-ras codon 12 were not detected in any of the healthy controls, but were identified in 13 (41.9%) of the 31 patients with colorectal cancer. Mutations were detectable in all six synthetic mutant DNAs, while none were detected among the wild type, The detection limit of this method was greater than or equal to 0.1%. Conclusions: PCR/RFLP analysis could be used in mass screening for colorectal cancer, because it is highly specific, has a low detection limit, and is simpler than conventional methods for detecting genetic abnormalities. (C) 2002 Elsevier Science B.V. All rights reserved.

Exposure of three colon cancer cell lines, SW480, DLD-1, and COLO201, to arsenic trioxide in the medium induced a marked concentration-dependent suppression of cell growth. The intracellular contents of reduced glutathione (GSH) in these cell lines tended to be inversely correlated with the sensitivity of the cells to arsenic trioxide. Among the cell lines, SW480 cells underwent apoptosis at the low arsenic trioxide concentration of 2 muM, which was prevented by pretreatment of the cells with N-acetylcysteine and was enhanced by buthionine sulfoximine. The production of reactive oxygen intermediates which were examined by 2',7'-dichlorodihydrofluorescein diacetate (H2DCF-DA), increased with time after treatment with arsenic trioxide. The apoptosis was executed by the activation of caspase 3, which was shown by Western blot, enzymatic activity, and apoptosis inhibition assay. The mitochondrial membrane potential of adherent apoptotic SW480 cells and the cells from intermediate layer separated by density gradient centrifugation, both of which showed the active form of caspase 3 by Western blot analysis, was not lost. The overexpression of Bcl-2 protein in SW480 cells could not prevent the apoptosis induced by the treatment with arsenic trioxide. All these findings indicate that arsenic trioxide-induced apoptosis in SW480 cells is executed by the activation of caspase 3 without mediating by mitochondria under the overproduction of reactive oxygen species. (C) 2002 Elsevier Science Inc. All rights reserved.

The RCK gene was cloned through a study of the breakpoint of the t(11;14)(q23;q32) chromosomal translocation observed in a human B-cell lymphoma and overexpression of the protein (rck/p54) due to the translocation was shown to be associated with malignant transformation. The rck/p54 protein belongs to the DEAD box protein/RNA helicase family, which has a variety of functions such as translation initiation, pre-mRNA splicing and ribosome assembly. It is considered that rck/p54 protein may have significant effects on the mRNA structure of genes associated with cell proliferation, facilitating protein synthesis. Expression of rck/p54 in colorectal adenomas, which are a premalignant lesion of colorectal cancer, was examined by Western blot analysis and immunohistochemistry. The rck/p54 protein was found to be overexpressed in tumor tissues resected from 17 of 26 cases (65.4%) of colorectal adenomas and 13 of 14 c-myc-positive cases (92.8%) also co-overexpressed rck/p54 protein. Thus, a significant correlation between rck/p54 and c-myc co-overexpression was found (Spearman's rank correlation, P = 0.0018). We demonstrate that overexpression of rck/p54 in two different cell lines, COS 7 and human colorectal cancer cell line SW480, caused an increase in c-myc protein levels by enhancement of its translation efficiency and/or stabilization of its mRNA. These results suggest that rck/p54 of the DEAD box protein/RNA helicase family may contribute to cell proliferation and carcinogenesis in the development of human colorectal tumors at the translational level by increasing synthesis of c-myc protein.

Fragile histidine triad (FHIT) gene is involved in deletions on the short arm of chromosome 3 in various human cancers. We found that 47% of colorectal adenomas, which is a higher frequency than that of H-ras, showed altered expression of the Fhit protein by Western blot analysis. The amount of Fhit protein was inversely correlated with the degree of dysplasia. Importantly, 27% of low-grade dysplastic adenomas showed altered expression of Fhit protein. Additionally, expression of human Fhit protein in human colon carcinoma cell line SW480 exhibited a marked inhibition of growth and rendered SW480 cells highly susceptible to undergo apoptosis compared with control cells. These findings suggest that altered expression of the FHIT gene is a quite early aberration in the development of colorectal tumors and that Fhit protein may act as a tumor suppressor. (C) 2000 Academic Press.

We examined the PLD activities of human renal cancers and found that the PLD2 activity was greatly elevated in almost all cases examined as compared with the adjacent normal region. Western blot analysis showed the increased levels of PLD2 protein, but the PLD1 was not discernible. The oleate-dependent PLD activity was very low but appeared to increase in most cases. Interestingly, the immunohistochemical observations indicated the high expression of PLD2 in the nuclei of clear carcinoma cells. This is the first demonstration which suggests the possible involvement of PLDS in tumorigenesis of renal cancer. (C) 2000 Academic Press.

PURPOSE: Patients undergoing urinary diversion by ureterosigmoidostomy after complete cystectomy for malignant bladder tumors show a high incidence of neoplasia at and near the site of anastomosis. We examined a risk factor for tumor occurrence in the area of anastomosis, alterations of mucus glycoproteins in the surrounding colonic mucosa. METHODS: Colonoscopy was performed in 37 patients who had undergone ureterosigmoidostomy. Biopsy specimens were obtained near the ureteral anastomosis and were stained with hematoxylin and eosin, high iron-diamine alcian blue (pH 2.5), and a fluorescent lectin conjugate (peanut agglutinin). RESULTS: At the anastomotic site colonoscopy showed protruding lesions in 26 of 37 patients (71 percent), all histologically representing inflammatory granulomas. The mucosa around the anastomosis was normal in endoscopic appearance; however, histologically, slight inflammatory cell infiltration, edema, and increased numbers of Paneth cells were observed. Alcian blue staining revealed an increase in mucosal sialomucin postoperatively compared with preoperatively. The proportion of peanut agglutinin-binding mucin, not observed in normal mucosa but seen in malignant or premalignant tissue, was increased. CONCLUSION: As postoperative interval increases, changes in properties of the "background" mucosa become greater, which suggests an association with colonic carcinogenesis.

Arsenic trioxide-induced apoptosis was identified by morphological change and nucleosomal DNA fragmentation in hematopoietic malignant cells and neuroblastoma cells. Arsenic trioxide directly induced apoptosis in the acute promyelocytic cell line NB4 cells at a low dose of 1 mu M, whereas all-trans-retinoic acid caused the cells to differentiate and finally induced apoptosis, In addition to the involvement of caspase 3 in arsenic trioxide-induced apoptosis of NB4 cells, the activation of caspase 8 was also shown to be involved by Western blot analysis or by apoptosis inhibition assay using caspase 8 inhibitor Ac-IETD-CHO, The down-regulation of Bcl-2 protein was shown in arsenic trioxide-treated pre-apoptotic and early apoptotic mouse B-cell line LyH7 cells, which overexpress Bcl-2 protein, by the studies of Western blot and immunoelectron microscopy, Arsenic trioxide also induced apoptosis in the majority of neuroblastomas cell lines, The arsenic-induced apoptosis in neuroblastoma cell lines was mediated by the activation of caspase 3 in all cases tested. In regard to the intracellular content of reduced glutathione in various neuroblastoma cell Lines, the level in the cells sensitive to arsenic trioxide was under 40 nmol/mg protein, but the cells having more than 40 nmol/mg protein did not undergo apoptosis. N-acetylcysteine protected neuroblastoma cells from arsenic-induced apoptosis. Therefore, the intracellular glulathione content may be a good indicator of application of arsenic trioxide for various kinds of cancer cells. Our results raise the possibility that arsenic trioxide will be effective even against a solid tumor such as neuroblastoma and warrants clinical trials for patients with other kinds of tumors not only by systemic therapy but also using local therapy.

An endogenous dopamine-derived N-methyl(R)salsolinol has been suggested to be involved in the pathogenesis of Parkinson's disease. In Parkinson's disease, the level of N-methyl(R)salsolinol increased in cerebrospinal fluid and the high activity of a synthesizing enzyme, (R)salsolinol N-methyltransferase, was detected in lymphocytes. This isoquinoline induced apoptotic DNA damage in human dopaminergic neuroblastoma SH-SY5Y cells. Among catechol isoquinolines, only N-methylsalsolinol induced apoptosis in the cells, and the scavengers of hydroxyl radicals and antioxidants suppressed DNA damage, suggesting that reactive oxygen species initiate apoptosis. The isoquinoline activated caspase-3 like proteases and a caspase-3 inhibitor protected the cells from DNA damage. (-)Deprenyl, but neither clorgyline nor pargyline, prevented apoptotic cell death. The mechanism of the protection was due to stabilization of mitochondrial membrane potential reduced by the toxin. In Parkinson's disease apoptosis may be induced in dopamine neurons by this endogenous neurotoxin, and (-)deprenyl may protect them from apoptotic death process.

Arsenic trioxide (As2O3) induces clinical remission in acute promyelocytic leukemia, even in all-tr ans retinoic acid-refractory cases, with minimal toxicity at low (1-2 mu M) concentration. We exposed various neuroblastoma cell fines to As2O3 at a concentration of 2 mu M: as a result, seven of 10 neuroblastoma cell lines underwent apoptosis characterized by morphological changes and nucleosomal DNA fragmentation. As2O3-induced apoptosis in neuroblastoma cells was shown to occur through the activation of caspase 3, as judged from Western blot analysis and apoptosis inhibition assay. It seemed that the sensitivity of neuroblastoma cells to As2O3 was inversely proportional to their intracellular level of reduced glutathione, Taken together these results indicate that As2O3 would be a candidate as a therapeutic agent for treatment of neuroblastoma, which is a solid tumor, not only by systemic therapy but also by local therapy. (C) 1999 Federation of European Biochemical Societies.

An endogenous neurotoxin, N-methyl(R)salsolinol, has been proved to be involved in the pathogenesis of Parkinson's disease. Increased level of N-methyl(R)salsolinol in the cerebrospinal fluid and high activity of its synthesizing (R)salsolinol N-methyltransferase in lymphocytes were confirmed in the majority of parkinsonian patients. Recently this neurotoxin was found to induce apoptosis in human dopaminergic neuroblastoma SH-SY5Y cells. In this study, we tried to elucidate the intracellular mechanism of apoptosis induced by N-methyl(R)salsolinol, and proved activation of caspase 3 after incubation with this toxin by Western blot analysis. Further, a caspase 3 inhibitor, acetyl-L-aspartyl-L-glutamyl-L-valyl-L-aspartic aldehyde, prevented the nucleosomal DNA fragmentation completely. These results demonstrate that caspase 3 mediates apoptosis induced by an endogenous neurotoxin, N-methyl(R)salsolinol, which may cause apoptotic cell death of dopamine neurons in Parkinson's disease. (C) 1999 Elsevier Science ireland Ltd. All rights reserved.

The RCK gene is a target of the t(11;14)(q23;q32) chromosomal translocation observed in human B-cell lymphoma, and the overexpression of its protein (rck/p54) by the translocation was shown to cause malignant transformation. The rck/p54 protein belongs to the DEAD box protein/RNA helicase family, which has a variety of functions such as translation initiation, pre-mRNA splicing and ribosome assembly. The expression of rck p54 in colorectal adenocarcinoma cells was examined by immunohistochemistry and Western blot analysis. The rck/p54 protein was found to be overexpressed in tumour tissues resected from 13 (50%) out of 26 cases of colorectal adenocarcinomas and two out of two (100%) cases of colonic severe dysplastic adenomas. In view of activities of rck/p54 determined in other tissue types, we suggest that rck/p54 may contribute to the cell proliferation and carcinogenesis at the translational level in the development of colorectal tumours.

To examine whether two DEAD box genes, DDX1 and DDX6, would have some roles in the progression of tumors, we investigated the correlation of the expression of these genes with that of MYCN in neuroblastomas either with or without MYCN amplification. The mRNA of MYCN was observed only in the cell lines with amplification of MYCN. The mRNAs of DDX1 and DDX6 were found in all the cell lines examined, but the correlation between the mRNA levels of DDX1 or DDX6 and MYCN was poor. These findings suggest that the expression of neither DEAD box gene is correlated with the gene expression of MYCN.