Inhibition of tumor cell-induced platelet aggregation using a novel anti-podoplanin antibody reacting with its platelet-aggregation-stimulating domain

The mucin-type sialoglycoprotein, podoplanin (aggrus), is a platelet-aggregating factor on cancer cells. We previously described up-regulated expression of podoplanin in malignant astrocytic tumors including glioblastoma. Its expression was associated with tumor malignancy. In the present study, we investigated podoplanin expression and platelet-aggregating activities of glioblastoma cell lines. First, we established a highly reactive anti-podoplanin antibody, NZ-1, which inhibits podoplanin-induced platelet aggregation completely. Of 15 glioblastoma cell lines, LN319 highly expressed podoplanin and induced platelet aggregation. Glycan profiling using a lectin microarray showed that podoplanin on LN319 possesses sialic acid, which is important in podoplanin-induced platelet aggregation. Interestingly, NZ-1 neutralized platelet aggregation by LN319. These results suggest that podoplanin is a main reason for platelet aggregation induced by LN319. We infer that NZ-1 is useful to determine whether platelet aggregation is podoplanin-specific or not. Furthermore, podoplanin might become a therapeutic target of glioblastoma for antibody-based therapy.     

Intestinal and peri-tumoral lymphatic endothelial cells are resistant to radiation-induced apoptosis

Radiation therapy is a widely used cancer treatment, but it is unable to completely block cancer metastasis. The lymphatic vasculature serves as the primary route for metastatic spread, but little is known about how lymphatic endothelial cells respond to radiation. Here, we show that lymphatic endothelial cells in the small intestine and peri-tumor areas are highly resistant to radiation injury, while blood vessel endothelial cells in the small intestine are relatively sensitive. Our results suggest the need for alternative therapeutic modalities that can block lymphatic endothelial cell survival, and thus disrupt the integrity of lymphatic vessels in peri-tumor areas.     

Coordinated intracellular translocation of phosphoinositide-specific phospholipase C-delta with the cell cycle

The delta family phosphoinositide (PI)-specific phospholipase C (PLC) are most fundamental forms of eukaryotic PI-PLCs. Despite the presence of lipid targeting domains such as the PH domain and C2 domain, the isoforms are also found in the cytoplasm and nucleus as well as at the plasma membrane. The isoforms have sequences or regions that can serve as a nuclear localization signal (NLS) and a nuclear export signal (NES). Their intracellular localization differs from one isoform to another, presumably due to the difference in the transport equilibrium balanced by the strength of the two signals of each isoform. Even for a particular isoform, its intracellular localization seems to vary during the cell cycle. As an example, PLCdelta(1), which is generally found at the plasma membrane and in the cytoplasm of quiescent cells, localizes to discrete nuclear structures in the G(1)/S boundary of the cell cycle. This may be at least partly due to an increase in intracellular Ca(2+), since Ca(2+) facilitates the formation of a nuclear transport complex comprised of PLCdelta(1) and importin beta1, a carrier molecule for the nuclear import. PLCdelta(1) as well as PLCdelta(4) may play a pivotal role in controlling the initiation of DNA synthesis in S phase. Spatio-temporal changes in the levels of PtdIns(4,5)P(2) seem to be another major determinant for the localization and regulation of the delta isoforms. High nuclear PtdIns(4,5)P(2) levels are associated with the G(1)/S phases. After entering M phase, PtdIns(4,5)P(2) synthesis at sites of cell division occurs and PLCs seem to localize to the cleavage furrow during cytokinesis. Coordinated translocation of PLCs with the cell cycle or with stress responses may result in changes in intra-nuclear environments and local membrane architectures that modulate proliferation and differentiation. In this review, recent findings regarding the molecular machineries and mechanisms of the nucleocytoplasmic shuttling as well as roles in the cell cycle progression of the delta isoforms of PLC will be discussed.     

ALLERDB database and integrated bioinformatic tools for assessment of allergenicity and allergic cross-reactivity

Databases and computational tools are increasingly important in the study of allergies, particularly in the assessment of allergenicity and allergic cross-reactivity. ALLERDB database contains sequences of allergens and information on reported cross-reactivity between allergens. It focuses on analysis of allergenicity and allergic cross-reactivity of clinically relevant protein allergens. The official IUIS allergen data were extracted from the IUIS Allergen Nomenclature Sub-Committee website, and their sequence information from the public databases, and reference publications. The analysis tools assist allergen data analysis and retrieval, and include keyword searching, BLAST, prediction of allergenicity, modification of BLAST that displays cross-reactive allergens, and graphics representation of cross-reactivity data. ALLERDB is new brand of allergen databases with a rich set of tools for sequence comparison, pattern identification, and visualization of results. It is accessible at http://research.i2r.a-star.edu.sg/Templar/DB/Allergen.     

Unpredictability induced by unfocused games in evolutionary game dynamics

Evolutionary game theory is a basis of replicator systems and has applications ranging from animal behavior and human language to ecosystems and other hierarchical network systems. Most studies in evolutionary game dynamics have focused on a single game, but, in many situations, we see that many games are played simultaneously. We construct a replicator equation with plural games by assuming that a reward of a player is a simple summation of the reward of each game. Even if the numbers of the strategies of the games are different, its dynamics can be described in one replicator equation. We here show that when players play several games at the same time, the fate of a single game cannot be determined without knowing the structures of the whole other games. The most absorbing fact is that even if a single game has a ESS (evolutionary stable strategy), the relative frequencies of strategies in the game does not always converge to the ESS point when other games are played simultaneously.     

Liquid chromatography-mass spectrometric assay of androstenediol in prostatic tissue: influence of androgen deprivation therapy on its level

Androstenediol (Adiol, androst-5-ene-3beta,17beta-diol) is suspected of being an endogenous proliferation agent of prostate cancer (PCa) even after androgen deprivation therapy (ADT). A liquid chromatography-electron capture atmospheric pressure chemical ionization-mass spectrometric (LC-ECAPCI-MS) method for the determination of Adiol in prostatic tissue was developed and validated for evaluating the influence of ADT on the prostatic Adiol level. After derivatization of Adiol with 4-nitrobenzoyl chloride, the detection response of the derivative was increased 150 times more than that of intact Adiol. The LC-MS method was specific and reliable for the measurement of a trace amount of Adiol in 30 mg of tissue. The clinical study using the developed method showed that the prostatic Adiol level was not changed by ADT. That is, the prostatic Adiol levels of PCa patients with ADT (n = 12), benign prostate hypertrophy patients without ADT (n = 8) and bladder cancer patients (without prostatic disease) (n = 6) were 0.83 +/- 0.28, 0.62 +/- 0.31 and 0.71 +/- 0.28 ng g(-1)tissue, respectively, and there was no significant difference between these groups.     

Molecular mapping of a gene ‘ld(t)’ controlling cleistogamy in rice

Cleistogamy is the self-pollination within closed spikelets and is expected to be a useful genetic tool for prevention of possible gene transfer in transgenic crops, for maintenance of genetic purity in autogamous crops, and for increased tolerance to biotic and abiotic stresses. Mapping of the gene ld(t), which is responsible for lack of lodicules inside spikelets and causes cleistogamy, was carried out using F₂ and F₃ populations derived from a cleistogamous (CL) mutant CL-SNU × Milyang 23 cross. A number of STS markers along chromosomes were developed and bulked segregant analysis was adopted for preliminary mapping. The results showed that the ld(t) was located at the end region of chromosome 1L, flanked by S01178b (an STS marker developed for the locus at 178 cM based on the rice genetic map reported by Japanese Rice Genome Project) at 0.8 cM and co-segregated with S01181a and S01181b (an STS marker developed for the locus at 181 cM).     

Metabolic profiling of flavonoids in Lotus japonicus using liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry

Flavonoids detected from a model legume plant, Lotus japonicus accessions Miyakojima MG-20 and Gifu B-129, were profiled using liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICR/MS). Five flavonols and two anthocyanidins were detected as aglycones. LC-FTICR/MS facilitated simultaneous detection of 61 flavonoids including compounds that have not been reported previously. Chemical information of the peaks such as retention time, lambdamax, m/z value of the quasi-molecular ion, m/z value of MS/MS fragment ions, and relative intensity of MS/MS fragments was obtained, along with the molecular formulas and conjugate structures. Fourteen were completely identified by comparison with authentic compounds. The high accuracy of m/z values, being 0.081 ppm between observed and theoretical values, allowed prediction of molecular formulas of unknown compounds with the help of isotope peak information for determination of chemical composition. Based on a predicted elemental composition, the presence of a novel nitrogen-containing flavonoid was proposed. A comparison of flavonoid profiles in flowers, stems, and leaves demonstrated that the flowers yielded the most complex profile, containing 30 flower-specific flavonoids including gossypetin glycosides and isorhamnetin glycosides. A comparison of flavonoid profiles between MG-20 and B-129 grown under the same conditions revealed that the accumulation of anthocyanins was higher in B-129 than MG-20, particularly in the stem. Developmental changes in the flavonoid profiles demonstrated that kaempferol glycosides increased promptly after germination. In contrast, quercetin glycosides, predominant flavonoids in the seeds, were not detectable in growing leaves.