Plakevulin a induces apoptosis and suppresses IL-6-induced STAT3 activation in HL60 cells.

(+)-Plakevulin A (1), an oxylipin isolated from an Okinawan sponge Plakortis sp. inhibits enzymatic inhibition of DNA polymerases (pols) α and δ and exhibits cytotoxicity against murine leukemia (L1210) and human cervix carcinoma (KB) cell lines. However, the half-maximal inhibitory concentration (IC50) value for cytotoxicity significantly differed from those observed for the enzymatic inhibition of pols α and ß, indicating the presence of target protein(s) other than pols. This study demonstrated cytotoxicity against human promyelocytic leukemia (HL60), human cervix epithelioid carcinoma (HeLa), mouse calvaria-derived pre-osteoblast (MC3T3-E1), and human normal lung fibroblast (MRC-5) cell lines. This compound had selectivity to cancer cells over normal ones. Among these cell lines, HL60 exhibited the highest sensitivity to (+)-plakevulin A. (+)-Plakevulin A induced DNA fragmentation and caspase-3 activation in HL60 cells, indicating its role in apoptosis induction. Additionally, hydroxysteroid 17-ß dehydrogenase 4 (HSD17B4) was isolated from the HL60 lysate as one of its binding proteins through pull-down experiments using its biotinylated derivative and neutravidin-coated beads. Moreover, (+)-plakevulin A suppressed the activation of interleukin 6 (IL-6)-induced signal transducer and activator of transcription 3 (STAT3). Because the knockdown or inhibition of STAT3 induces apoptosis and HSD17B4 regulates STAT3 activation, (+)-plakevulin A may induce apoptosis in HL60 cell lines by suppressing STAT3 activation, potentially by binding to HSD17B4. The present findings provide valuable information for the mechanism of its action.

Epo-C12 inhibits peroxiredoxin 1 peroxidase activity.

Epo-C12 is a synthetic derivative of epolactaene, isolated from Penicillium sp. BM 1689-P. Epo-C12 induces apoptosis in human acute lymphoblastoid leukemia BALL-1 cells. In our previous studies, seven proteins that bind to Epo-C12 were identified by a combination of pull-down experiments using biotinylated Epo-C12 (Bio-Epo-C12) and mass spectrometry. In the present study, the effect of Epo-C12 on peroxiredoxin 1 (Prx 1), one of the proteins that binds to Epo-C12, was investigated. Epo-C12 inhibited Prx 1 peroxidase activity. However, it did not suppress its chaperone activity. Binding experiments between Bio-Epo-C12 and point-mutated Prx 1s suggest that Epo-C12 binds to Cys52 and Cys83 in Prx 1. The present study revealed that Prx 1 is one of the target proteins through which Epo-C12 exerts an apoptotic effect in BALL-1 cells.

Different hollow and spherical TiO2 morphologies have distinct activities for the photocatalytic inactivation of chemical and biological agents.

The inactivation of Escherichia coli and Qß phage was examined following their photocatalytic treatment with TiO2 hollows and spheres that had been prepared by electrospray, hydrothermal treatment, and calcination. The crystal structures of the hollows and spheres were assigned to TiO2 anatase, and the surface areas of the hollows and spheres were determined to be 91 and 79 m(2) g(-1), respectively. Interestingly, TiO2 spheres exhibited higher anti-pathogen performance than TiO2 hollows, a difference we ascribe to the prevention of light multi-scattering by microorganisms covering the surfaces of the TiO2 particles. The photocatalytic decomposition of dimethyl sulfoxide (DMSO) in the presence of TiO2 hollows and spheres was examined in order to study the dependence of photocatalytic activity on TiO2 morphology for the size scale of the reactants. TiO2 hollows provided greater photocatalytic decomposition of DMSO than did TiO2 spheres, in contrast to the pattern seen for pathogen inactivation. Fabrication of photocatalysts will need to vary depending on what substance (e.g., organic compound or biological agent) is being targeted for environmental remediation.

Novel tamoxifen derivative Ridaifen-B induces Bcl-2 independent autophagy without estrogen receptor involvement.

Autophagy is a self-proteolysis process in eukaryotic cells that results in the sequestering of intracellular proteins and organelles in autophagosomes. Activation of autophagy progress continued growth of some tumors, instead extensive autophagy induces cell death. In a previous study, we synthesized a novel tamoxifen derivative, Ridaifen (RID)-B. RID-B induced mitochondria-involved apoptosis even in estrogen receptor (ER)-negative cells. Since tamoxifen induces autophagy other than apoptosis, we treated ER-negative Jurkat cells with RID-B in the present study. RID-B treatment induced apoptosis and LC3 and lysosome colocalization, which results in the formation of autolysosomes. Western blotting revealed that LC3 was converted to LC3-I to LC3-II with RID-B treatment, suggesting that RID-B induced autophagy without ER involvement. Moreover, overexpression of the anti-apoptotic protein Bcl-2 suppressed the RID-B-induced cell death, but not the induction of autophagy. These results presumed that RID-B-induced autophagy is independent of Bcl-2, making RID-B-induced autophagy different from RID-B-induced apoptosis. Since Beclin 1 level is unchanged during RID-B treatment, RID-B induced autophagy pathway is Bcl-2/Beclin1 independent noncanonical pathway.

Potential tumor markers of renal cell carcinoma: α-enolase for postoperative follow up, and galectin-1 and galectin-3 for primary detection.

The diagnosis of renal cell carcinoma is currently based on imaging techniques, mainly because there is no blood marker available for its detection. Thus, there is still the need for the development of novel tumor markers. We examined plasma levels of eight proteins in 15 renal cell carcinoma patients before and after surgery, and in 51 healthy controls using enzyme-linked immunosorbent assay. Plasma levels of α-enolase, calnexin, galectin-1, galectin-3 and lectin mannose-binding 2 were significantly higher in renal cell carcinoma patients than in controls (P < 0.05). Among these proteins, the sensitivities for galectin-1 and galectin-3 were higher than those for calnexin and lectin mannose-binding 2 in the specificity range from 80% to 100%. A combined use of galectin-1 and galectin-3 showed 98% specificity and 47% sensitivity. In addition, the assays showed that plasma α-enolase levels decreased significantly 4 weeks after nephrectomy (P = 0.0034), and this tendency continued until 12 weeks after nephrectomy (P = 0.0156). These findings suggest that α-enolase could be used in the postoperative follow up of renal cell carcinoma patients, whereas the combined use of galectin-1 and galectin-3 might represent a useful tool for primary detection.

Asn54-linked glycan is critical for functional folding of intercellular adhesion molecule-5.

Intercellular adhesion molecule-5 (ICAM-5, telencephalin) is a dendritically polarized type I membrane glycoprotein, and promotes dendritic filopodia formation. Although we have determined the N-glycan structures of ICAM-5 in a previous report, their function is unknown. Here, we produced fifteen ICAM-5 gene constructs, in which each potential N-glycosylation site was mutated, to elucidate the function of the N-glycans of ICAM-5, and observed the effects of transfection of them on a neuronal cell line, Neuro-2a (N2a). Only the N54Q mutant, which is the mutant for the most N-terminal glycosylation site, failed to induce filopodia-like protrusions in N2a cells. Immunofluorescence staining and cell surface biotinylation revealed that N54Q ICAM-5 was confined to the ER and also could not be expressed on the cell surface. This is further supported by the biochemical evidence that almost all N-glycans of N54Q ICAM-5 were digested by Endo glycosidase H and peptide:N-glycanase, indicating that almost all of them retain high-mannose-type structures in ER. In additon, it also failed to form disulfide bonds or functional protein complexes. The stable transformants of N54Q ICAM-5 showed retarded cell growth, but it was interesting that there was no apparent ER stress, because the mutant was sequentially degraded via ER associated degradation pathway by comparing the susceptibilities of the responses to various inhibitors of this pathway in wild-type and N54Q ICAM-5 transfectants. Taken together, the Asn(54)-linked glycan is necessary for normal trafficking and function of ICAM-5, but is unassociated with ER-associated degradation of it.

3-(3-Phenoxybenzyl)amino-ß-carboline: a novel antitumor drug targeting α-tubulin.

3-(3-Phenoxybenzyl)amino-ß-carboline 2h showed extremely-high activity; the IC(50) value was 0.074 µM. To verify 2h-induced cell death types, we observed the chromatin condensation, the DNA fragmentation and activated caspase-3 using Hoechst 33342, agarose electrophoresis and western blot, and suggesting 2h-induced cell death type was apoptosis. Flow cytometry showed that 2h-treated cell was induced SubG1 cell population after G2/M cell cycle arrest. In addition, using affinity chromatography and peptide mass fingerprinting, we found that interacting protein with this compound was α-tubulin protein.

Transformation of thiols to disulfides by epolactaene and its derivatives.

In this paper we report a disulfide formation of thiols induced by epolactaene and its derivatives. We previously reported the disulfide formation of N-acetylcysteine methyl ester by epolactaene in a 1:1 MeOH/0.5M NaHCO(3) aq solution. The present studies reveal that the disulfide formation proceeds under mild conditions such as in PBS at pH 7.3, suggesting that epolactaene may induce disulfide formation of cellular thiols. This compound induces the disulfide formation of several thiols in a 1:1 MeOH/0.5M NaHCO(3) aq solution at room temperature. Moreover, our results show that the acyl side-chain of epolactaene greatly influences the products of the reaction. We analyzed the reaction mechanism by using thiolysis products of epolactaene derivatives and propose a new reaction mechanism.

Involvement of Galectin-3 with vascular cell adhesion molecule-1 in growth regulation of mouse BALB/3T3 cells.

beta-Galactose residues on N-glycans have been implicated to be involved in growth regulation of cells. In the present study we compared the galactosylation of cell surface N-glycans of mouse Balb/3T3 cells between 30 and 100% densities and found the beta-1,4-galactosylation of N-glycans increases predominantly in a 100-kDa protein band on lectin blot analysis in combination with digestions by diplococcal beta-galactosidase and N-glycanase. When cells at 100% density were treated with jack bean beta-galactosidase, the incorporation of 5-bromodeoxyuridine into the cells was stimulated in a dose-dependent manner, suggesting the involvement of the galactose residues in growth regulation of cells. A galactose-binding protein was isolated from the plasma membranes of cells at 100% density by affinity chromatography using an asialo-transferrin-Sepharose column and found to be galectin-3 as revealed by mass spectrometric analysis. The addition of recombinant galectin-3 into cells at 50% density inhibited the incorporation of 5-bromodeoxyuridine in a dose-dependent manner, but the inhibition was prevented with haptenic sugar. An immunocytochemical study showed that galectin-3 is present at the surface of cells at 100% density but not at 30% density where it locates inside the cells. Several glycoproteins bind to a galectin-3-immobilized column, a major of which was identified as vascular cell adhesion molecule (VCAM)-1. Immunocytochemical studies showed that some galectin-3 and VCAM-1 co-localize at the surface of cells at 100% density, indicating that the binding of galectin-3 secreted from cells to VCAM-1 is one of the pathways involved in the growth regulation of Balb/3T3 cells.

Structural study of the N-glycans of intercellular adhesion molecule-5 (telencephalin).

Intercellular adhesion molecule-5 (ICAM-5, telencephalin) is a dendritically polarized membrane glycoprotein expressed in tissues distinct from those expressing other ICAMs. Here, we determined the N-glycan structure of ICAM-5 purified from adult rat brain and compared it with that of other ICAMs. N-glycans were released by N-glycosidase F digestion and labeled with p-amino benzoic octylester (ABOE). ABOE-labeled glycans were analyzed by high performance liquid chromatography (HPLC) and mass spectrometry. The N-glycans obtained from rat brain ICAM-5 consisted of approximately 85% neutral, 10.2% sialylated-only, 2.8% sulfated-only, and 1.2% sialylated and sulfated glycans. Compared with the N-glycan structures of human ICAM-1 expressed in CHO cells, HEK cells, or mouse myeloma cells and ICAM-3 isolated from human T-cells, rat brain ICAM-5 had less highly branched glycans, sialylated glycans, and N-acetyllactosamine structures. In contrast, high-mannose-type N-glycans and Lewis X were more commonly found in rat brain ICAM-5 than in human ICAM-1 expressed in CHO cells, HEK cells, or mouse myeloma cells and ICAM-3 isolated from human T-cells. In addition, sulfated glycans contained GlcNAc 6-O-sulfate on the non-reducing terminal side. Our data will be important for the elucidation of the roles of the N-glycans expressed in neural cells, including those present on ICAM-5.

Glycosaminoglycan affinity of the complete fibroblast growth factor family.

BACKGROUND: Many fibroblast growth factor family proteins (FGFs) bind to the heparan sulfate/heparin (HP) subtypes of sulfated glycosaminoglycans (GAGs), and a few have recently been reported to also interact with chondroitin sulfate (CS), another sulfated GAG subtype. METHODS: To gain additional insight into this interaction, we prepared all currently known FGFs (i.e., FGF1-FGF23) and assessed their affinity for HP, CS-B, CS-D and CS-E. In addition, midkine, hepatocyte growth factor and pleiotrophin were studied as other known HP-binding proteins. RESULTS: We found that members of the FGF19 subfamily (i.e., FGF15, 19, 21 and 23) had little or no affinity for HP; all of the other secretable growth factors tested had strong affinities for HP, as was indicated by the finding that their elution from HP-Sepharose columns required 1.0-1.5 M NaCl. We also found that FGF3, 6, 8 and 22 had strong affinities for CS-E, while FGF5 had a moderate affinity for CS-D. The interactions between FGFs and GAGs thus appear to be more diverse than previously understood. GENERAL SIGNIFICANCE: This is noteworthy, as the differential interactions of these growth factors with GAGs may be key determinants of their specific biological activities.

Nobiletin, a citrus polymethoxyflavonoid, suppresses multiple angiogenesis-related endothelial cell functions and angiogenesis in vivo.

Nobiletin is a citrus polymethoxyflavonoid that suppresses tumor growth and metastasis, both of which depend on angiogenesis. We recently identified nobiletin as a cell differentiation modulator. Because cell differentiation is a critical event in angiogenesis, it might be possible that nobiletin could exhibit antiangiogenic activity, resulting in suppression of these tumor malignant properties. To verify this possibility, we examined the antiangiogenic effects of nobiletin in vitro and in vivo. Nobiletin had concentration-dependent inhibitory effects on multiple functions of angiogenesis-related endothelial cells (EC); it suppressed the proliferation, migration and tube formation on matrigel of human umbilical vein EC (HUVEC) stimulated with endothelial cell growth supplement (ECGS), a mixture of acidic and basic fibroblast growth factors (FGFs). Gelatin zymography and northern blotting revealed that nobiletin suppressed pro-matrix metalloproteinase-2 (proMMP-2) production and MMP-2 mRNA expression in ECGS-stimulated HUVEC. Nobiletin also downregulated cell-associated plasminogen activator (PA) activity and urokinase-type PA mRNA expression. Furthermore, nobiletin inhibited angiogenic differentiation induced by vascular endothelial growth factor and FGF, an in vitro angiogenesis model. This inhibition was accompanied by downregulation of angiogenesis-related signaling molecules, such as extracellular signal-regulated kinase 1/2 and c-Jun N-terminal kinase, and transcriptional factors (c-Jun and signal transducer and activator of transcription 3), and activation of the caspase pathway. In a chick embryo chorioallantoic membrane assay, nobiletin showed an antiangiogenic activity, the ID(50) value being 10µg (24.9nmol) per egg. These results indicate that nobiletin is a novel antiangiogenic compound that exhibits its activity through combined inhibition of multiple angiogenic EC functions.

Activin A induces neuronal differentiation and survival via ALK4 in a SMAD-independent manner in a subpopulation of human neuroblastomas.

Activin A is a multifunctional homo-dimeric protein that belongs to the transforming growth factor (TGF)-beta superfamily. In neurons, activin has neuroprotective effects both in vitro and in vivo, but it inhibits neuronal differentiation in some cell lines. Here we report that activin A can promote neuronal differentiation in particular cases. We examined activin A-induced neuronal differentiation and survival in a selected subpopulation of a human neuroblastoma cell line, SK-N-SH, grown in low-serum (differentiation-inducing) conditions. Activin A caused dramatic neurite outgrowth, and increased the expression of neuronal markers and the transactivation of dopamine beta-hydroxylase. We demonstrated that the activin A signal is transduced through the activin A type 1 receptor, ALK4, and transactivates several TGF-beta target genes in a SMAD-independent manner. That is, activin A did not induce the phosphorylation of SMAD2/3, the interaction of SMAD2/3 with SMAD4, the binding of SMAD2/3 to the promoter of TGF-beta target genes, or the accumulation of SMAD2/3 in the nucleus. These results suggest that, in particular cases, activin A can induce neuronal differentiation and support neuronal survival in vitro. These findings may reflect previously unknown functions of activin A in neuronal cells in vivo.

Design and synthesis of a fluorescent probe for Zn2+, 5,7-bis(N,N-dimethylaminosulfonyl)-8-hydroxyquinoline-pendant 1,4,7,10-tetraazacyclododecane and Zn2+-dependent hydrolytic and Zn2+-independent photochemical reactivation of its benzenesulfonyl-caged derivative.

We previously reported on a 8-quinolinol-pendant cyclen (L(5)) as a Zn(2+) fluorophore (cyclen = 1,4,7,10-tetraazacyclododecane) and its caged derivative, 8-(benzenesulfonyloxy)-5-(N,N-dimethylaminosulfonyl)quinolin-2-ylmethyl-pendant cyclen (BS-caged-L(5)), which can be reactivated by hydrolysis of benzenesulfonyl group upon complexation with Zn(2+) at neutral pH to give a 1:1 Zn(2+)-L(5) complex (Zn(H(-1)L(5))). We report herein on the synthesis of 5,7-bis(N,N-dimethylaminosulfonyl)-8-hydroxyquinolin-2-ylmethyl-pendant cyclen (L(6)) and its caged derivative (BS-caged-L(6)) for more sensitive and more efficient cell-membrane permeability than those of L(5) and BS-caged-L(5). By potentiometric pH, (1)H NMR, and UV-vis spectroscopic titrations, the deprotonation constants pK(a1)-pK(a6) of H(5)L(6) were determined to be <2, <2, <2, 2.5 +/- 0.1 (for the 8-OH group of the quinoline moiety), 9.7 +/- 0.1, and 10.8 +/- 0.1 at 25 degrees C with I = 0.1 (NaNO(3)). The results of (1)H NMR, potentiometric pH, UV-vis, and fluorescent titrations showed that L(6) rapidly forms a 1:1 complex with Zn(2+) (Zn(H(-1)L(6))), the dissociation constant of which is 50 fM at pH 7.4. The fluorescent emission of Zn(H(-1)L(6)) at 478 nm is 32 times as large as that of L(6) (excitation at 370 nm), and the fluorescent quantum yield of Zn(H(-1)L(6)) (Phi(F) = 0.41) is much greater than that of Zn(H(-1)L(5)) (Phi(F) = 0.044). The BS-caged-L(6) was reactivated by hydrolysis of the benzenesulfonyl moiety more rapidly (completes in 30 min at pH 7.4 at 37 degrees C) than BS-caged-L(5), presumably enabling the practical detection of Zn(2+) in sample solutions and living cells. The photochemical deprotection of BS-caged-L(6) and the cell membrane permeability of L(6) and BS-caged-L(6) are also described.

Induction of mitochondria-involved apoptosis in estrogen receptor-negative cells by a novel tamoxifen derivative, ridaifen-B.

Tamoxifen is an antagonist of estrogen receptor, which is used widely as an estrogen receptor-positive breast cancer drug that blocks growth signals and provokes apoptosis. However, recent studies have revealed that tamoxifen induces apoptosis even in estrogen receptor-negative cells. In the present study, we synthesized several tamoxifen derivatives to augment the apoptosis-inducing effect of tamoxifen and evaluated the apoptosis-inducing pathway. The estrogen receptor-positive human leukemia cell line HL-60 and estrogen receptor-negative human leukemia cell line Jurkat were treated with tamoxifen and synthesized tamoxifen derivatives, and thereafter subjected to cell viability-detection assays. Tamoxifen derivatives, as well as the lead compound tamoxifen, decreased the cell viability despite the expression of estrogen receptor. Among all of the synthesized tamoxifen derivatives, ridaifen-B had more potent cancer cell-damaging activity than tamoxifen. Ridaifen-B fragmented Jurkat cell DNA and activated caspases, suggesting that the ridaifen-B-induced apoptosis pathway is estrogen receptor independent. Moreover, mitochondrial involvement during ridaifen-B-induced apoptosis was estimated. Ridaifen-B significantly reduced mitochondrial membrane potential, and overexpression of Bcl-2 inhibited ridaifen-B-induced apoptosis. These results suggest that the induction of apoptosis by ridaifen-B, a novel tamoxifen derivative, is dependent on mitochondrial perturbation without estrogen receptor involvement.

Binding parameters and thermodynamics of the interaction of imino sugars with a recombinant human acid alpha-glucosidase (alglucosidase alfa): insight into the complex formation mechanism.

BACKGROUND: Recently, enzyme enhancement therapy (EET) for Pompe disease involving imino sugars, which act as potential inhibitors of acid alpha-glucosidases in vitro, to improve the stability and/or transportation of mutant acid alpha-glucosidases in cells was studied and attracted interest. However, the mechanism underlying the molecular interaction between the imino sugars and the enzyme has not been clarified yet. METHODS: We examined the inhibitory and binding effects of four imino sugars on a recombinant human acid alpha-glucosidase, alglucosidase alfa, by means of inhibition assaying and isothermal titration calorimetry (ITC). Furthermore, we built structural models of complexes of the catalytic domain of the enzyme with the imino sugars bound to its active site by homology modeling, and examined the molecular interaction between them. RESULTS: All of the imino sugars examined exhibited a competitive inhibitory action against the enzyme, 1-deoxynojirimycin (DNJ) exhibiting the strongest action among them. ITC revealed that one compound molecule binds to one enzyme molecule and that DNJ most strongly binds to the enzyme among them. Structural analysis revealed that the active site of the enzyme is almost completely occupied by DNJ. CONCLUSION: These biochemical and structural analyses increased our understanding of the molecular interaction between a human acid alpha-glucosidase and imino sugars.

Syntheses and applications of fluorescent and biotinylated epolactaene derivatives: Epolactaene and its derivative induce disulfide formation.

Epolactaene, isolated from cultured Penicillium sp. BM 1689-P mycelium, induces neurite outgrowth and arrests the cell cycle of the human neuroblastoma cell line, SH-SY5Y, at the G1 phase. We have found that epolactaene and its derivatives induce apoptosis in the human leukemia B-cell line, BALL-1. In this study, we prepared fluorescent and biotinylated epolactaene derivatives. We characterized the cellular location and the identification of BALL-1 proteins that reacted with these compounds. The results obtained from the reaction of epolactaene or its derivative with N-acetylcysteine methyl ester indicate that these compounds induce the disulfide formation and the alpha-position of the epoxylactam core is the reactive site.

An expeditious synthesis of tamoxifen, a representative SERM (selective estrogen receptor modulator), via the three-component coupling reaction among aromatic aldehyde, cinnamyltrimethylsilane, and beta-chlorophenetole.

Two new synthetic pathways to the anti-cancer agent tamoxifen and its derivatives were developed. The first route involved the aldol reaction of benzyl phenyl ketone with acetaldehyde followed by Friedel-Crafts substitution with anisole in the presence of Cl(2)Si(OTf)(2) to produce 1,1,2-triaryl-3-acetoxybutane, a precursor of the tamoxifen derivatives. The second one utilized the novel three-component coupling reaction among aromatic aldehydes, cinnamyltrimethylsilane, and aromatic nucleophiles using HfCl(4) as a Lewis acid catalyst to produce 3,4,4-triarylbutene, that is also a valuable intermediate of the tamoxifen derivatives. The former strategy requires a total of 10 steps from the aldol formation to the final conversion to tamoxifen, whereas the latter needs only three or four steps to produce tamoxifen and droloxifene including the installation of the side-chain moiety and the base-induced double-bond migration to form the tetra-substituted olefin structure. This synthetic strategy seems to serve as a new and practical pathway to prepare not only the tamoxifen derivatives but also the other SERMs (selective estrogen receptor modulators) including estrogen-dependent breast cancer and osteoporosis agents.

Coenzyme Q2 induced p53-dependent apoptosis.

Coenzyme Q functions as an electron carrier and reversibly changes to either an oxidized (CoQ), intermediate (CoQ.-), or reduced (CoQH2) form within a biomembrane. The CoQH2 form also acts as an antioxidant and prevents cell death, and thus has been successfully used as a supplement. On the other hand, the value of the CoQ/CoQH2 ratio has been shown to increase in a number of diseases, presumably due to an anti-proliferative effect involving CoQ. In the present study, we examined the effect of CoQ and its isoprenoid side chain length variants on the growth of cells having different p53 statuses. Treatment with CoQs having shorter isoprenoid chains, especially CoQ2, induced apoptosis in p53-point mutated BALL-1 cells, whereas treatment with longer isoprenoid chains did not. However, CoQ2 did not induce apoptosis in either a p53 wild-type cell line or a p53 null mutant cell line. These results indicated that the induction of apoptosis by CoQ2 was dependent on p53 protein levels. Moreover, CoQ2 induced reactive oxygen species (ROS) and the phosphorylation of p53. An antioxidant, l-ascorbic acid, inhibited CoQ2-induced p53 phosphorylation and further apoptotic stimuli. Overall, these results suggested that short tail CoQ induces ROS generation and further p53-dependent apoptosis.

Auxiliary liver organ formation by implantation of spleen-encapsulated hepatocytes.

Hepatocyte transplantation is an attractive alternative to orthotopic liver transplantation. However, its application has been limited because of its short-term success only. Here we report a new approach to hepatocyte transplantation resulting in the generation of an auxiliary liver in vivo. Isolated primary hepatocytes were encapsulated in isolated spleens and then transplanted by attaching the spleens to the livers of recipient animals (mice or rats) using biodegradable adhesive. A vascular network was rapidly established, and protein molecules circulated freely between the transplanted spleen and the liver, to which they adhered. In contrast, the spleen, which did not adhere to the liver or adhered elsewhere (adipose tissue or peritoneum), did not become vascularized but shrank and died. Encapsulation of hepatocytes in an isolated spleen enhanced their survival significantly, and co-encapsulation of Engelbreth- Holm-Swarm gel together with the hepatocytes further enhanced it. The encapsulated hepatocytes expressed liver-specific differentiation genes for more than 3 weeks. Plasma albumin concentrations in Nagase analbuminemic rats began to increase 3 days after transplantation. The transplanted hepatic cells migrated into the liver parenchyma, whereas the spleen was absorbed. Thus, we have developed a novel, simple approach for the rapid and efficient formation of functional auxiliary liver using a modified hepatocyte transplantation method.