Novel anticancer agents, kayeassamins A and B from the flower of Kayea assamica of Myanmar

The CHCl(3)-soluble fraction of 70% EtOH extract of the flower of Kayea assamica completely killed human pancreatic PANC-1 cancer cells preferentially under nutrient-deprived conditions at 1 microg/mL. Bioassay-guided fractionation and isolation afforded two novel compounds, kayeassamins A (1) and B (2). Their structures were elucidated using extensive spectroscopic methods and the modified Mosher method. Each compound showed 100% preferential cytotoxicity (PC(100)) against PANC-1 cells under nutrient-deprived conditions at 1 microM. Furthermore, both compounds inhibited the migration of PANC-1 cells in the wound closure assay.     

Regulations of the C2H4-forming system and the H2O2-scavenging system by heat treatment associated with self incompatibility in lily

The mechanism of self incompatibility in pistils of Lilium longiflorum Thunb. cv. Hinomoto, which is overcome by heat treatment, was analyzed. Immersing detached pistils in a distilled water bath held at 45°C for 5 min suppressed levels of ethylene and activities of 1-aminocyclopropane-1-carboxylate (ACC) oxidase at 6 h after self- and cross-incompatible pollination. However, the levels and activities showed no significant difference 48 h after pollination. Levels of ACC and activities of ACC synthase at 6 h after self-incompatible pollination were lower in pistils with heat treatment. Moreover, the heat treatment suppressed the activity of superoxide dismutase and enhanced the activity of catalase, ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase. In addition, the amount of hydrogen peroxide (H₂O₂) was reduced by heat treatment. In summary, heat treatment suppressed the ethylene-forming system and also enhanced the hydrogen peroxide-scavenging system in self-pollinated pistils associated with self incompatibility. A possible correlation between self incompatibility and stress in pistils after self-incompatible pollination is discussed based on the results obtained using heated pistils. Received: 12 April 2000 / Revision accepted: 19 September 2000     

Relationship between the self-incompatibility and cAMP level in Lilium longiflorum.

The elongation of pollen tubes in Lilium longiflorum cv. Hinomoto after self-incompatible pollination stopped halfway, but that after cross-compatible pollination (cross with cv. Georgia) did not. The elongation of pollen tubes after self-pollination was enhanced by exogenous cAMP and by pertussis toxin or cholera toxin, which activates adenylate cyclase. The level of endogenous cAMP in pistils after self-pollination was approximately one half of that after cross-pollination. Furthermore, the activity of adenylate cyclase in pistils after self-pollination was also approximately one half of that after cross-pollination. By contrast, cAMP phosphodiesterase in pistils after self-pollination was approximately 2 times as high as that after cross-pollination. A possible correlation between self-incompatibility and the low level of endogenous cAMP in lily pistils is discussed on the basis of these results.     

Quantitative fluorographic detection of 3H and 14C on two-dimensional thin-layer chromatographic sheets by an ultra-high-sensitivity TV camera system

A method for quantitative detection of 3H and 14C on thin layers is described. After impregnation of the TLC sheet with 50% 2,5-diphenyloxazole-tetrahydrofuran, quantitative imaging of the distribution of weak beta-ray-emitting isotopes on the chromatogram was carried out at room temperature by using a TV camera system, which consisted of a two-stage microchannel plate image intensifier, a low-lag vidicon, and an image processor. The method is applicable for 14C- and 3H-labeled samples on TLC sheets (10 X 10 cm) emitting more than 0.17 and 7.5 Bq/mm2, respectively. The method is rapid and has a dynamic range far greater than that of film.     

Successful tumor eradication was achieved by collaboration of augmented cytotoxic activity and anti-angiogenic effects following therapeutic vaccines containing helper-activating analog-loaded dendritic cells and tumor antigen DNA

We reported previously that pigeon cytochrome c-derived peptides (Pan-IA), which bind broad ranges of MHC class II molecules efficiently, activate T helper (Th) function in mice. In an experimental model, Pan-IA DNA vaccines augmented antitumor immunity in tumor antigen-immunized mice. To elicit more potent antitumor immunity and to eradicate tumors in a therapeutic setting, Pan-IA-loaded dendritic cells (DCs) were inoculated in combination with vaccines including ovalbumin (OVA) antigen DNA in tumor-bearing mice. Seventy percent of the immunized mice survived tumor-free for at least 4 months after treatment. In contrast, mice vaccinated with OVA DNA, either with or without naïve DCs, did not eliminate the tumors and died within 5 weeks. Only in mice vaccinated with OVA DNA and Pan-IA-loaded DCs were both cytotoxic and helper responses specific for OVA induced at the spleen and tumor sites as well as at the vaccination sites. Furthermore, accumulation of OVA-specific CD4⁺ and CD8⁺ T lymphocytes and interferon-gamma-mediated anti-angiogenesis were observed in the tumors of these mice. Thus, the combined vaccination primed both tumor-specific cytotoxicity and helper immunity resulting in augmented tumor lysis ability and anti-angiogenic effects. This is the first report to show that most established tumors were successfully eradicated by collaboration of potent antitumor immunity and anti-angiogenic effects by vaccination with tumor antigens and helper-activating analogs. This novel vaccination strategy is broadly applicable, regardless of identifying helper epitopes in target molecules, and contributes to the development of therapeutic cancer vaccines.     

Liposomal membranes. XIV. Fusion of liposomal membranes induced by polyisoprenoids as monitored by fluorescence quenching method

Fusion of the single-walled liposomes of egg phosphatidylcholine as induced by the polyisoprenoids such as solanesol, trans-ethyl decaprenoate (EDP), coenzyme Q10, and dolichol has been investigated adopting the fluorescence quenching method. Relative efficiency of the polyisoprenoids employed on the induced fusion of liposomes was a sequence of solanesol less than or equal to EDP much less than CoQ10, dolichol, which was consistent with the result previously obtained by the dye-release method.     

Identification of osteopontin in isolated rabbit osteoclasts.

Bone remodeling is a complex process coupling bone formation and resorption. Osteoblasts, the bone-forming cells, are known to produce various bone matrix proteins and cytokines; however, little is known about protein factors produced by osteoclasts or bone-resorbing cells. A method utilizing the high affinity of osteoclasts for tissue culture dishes was developed to isolate a large number of pure osteoclasts from rabbit long bones. A cDNA library was then constructed from these isolated osteoclasts, and differential cDNA screening was performed between osteoclasts and spleen cells. Two clones representing osteoclast-specific clones, named OC-1 and OC-2, were isolated. By Northern blot analysis, OC-1 was expressed in osteoclasts and in kidneys, whereas OC-2 was specific for osteoclasts. OC-1 was found to encode osteopontin from its nucleotide sequence, and therefore, osteopontin may have other functions for osteoclastic bone resorption besides osteoclast attachment to bone.