Cis-diamminedichloroplatinum(II) (CDDP) is considered as one of the most effective antitumor agents for ovarian carcinoma. CDDP-based chemotherapy has clearly improved the response rate in the treatment of ovarian carcinoma, but its clinical potential is often counteracted by intrinsic or acquired resistance and its impact on survival has been only marginal in most cases. Effective chemotherapy for ovarian carcinoma with such CDDP resistance is still not established. Thus, development of antitumor drugs which can be substituted for CDDP is of great importance.Ginseng is one of the most widely used natural tonics in Oriental countries. Odashima et al. 1,2) have reported that a crude fraction of ginsenosides extracted from roots of Panax ginseng CA Meyer induced a phenotypic reverse transformation in cultured Morris hepatoma cells. Ginsenoside Rh 2 (Rh 2 ) is a plant glycoside with a dammarane skeleton, resembling a steroid skeleton, as an aglycone; it has one sugar at C-3 and the capacity to inhibit the growth of and to stimulate melanogenesis in B16 melanoma cells. Recently, we have also demonstrated that i.p. and p.o. administration of Rh 2 inhibited the tumor growth of human ovarian cancer cells inoculated into nude mice and also had an adjuvant effect with CDDP.3, 4) In addition, it has been reported that the long-term p.o. administration of red ginseng augmented natural killer (NK) activity not only in mouse, but also in human. 5,6) The present study extends our previous in vitro and in vivo observations. We now report that p.o. administration of Rh 2 is superior to i.p. administration with regard to antitumor activity and has an apoptosis-inducing effect in addition to an augmenting effect on NK activity.

The reported pH values of ascidian blood cells vary considerably. It is likely that one or two of several different types of blood cell must have a highly acidic solution within their vacuoles, in which vanadium ions would be present in a reduced state. Thus, one of the reasons for the variation in reported pH values may be that measurements of pH were made without fractionation of the total population of cells. In the present experiments, the combination of fractionation of whole cells by density-gradient centrifugation, use of a microelectrode that allows measurements of pH under anaerobic conditions, and atomic absorption spectrometry for determinations of vanadium revealed that the contents of signet ring cells, recently identified as vanadocytes, of three ascidian species, Ascidia gemmata, A. ahodori, and A. sydneiensis samea, had low pH values of 2.4, 2.7, and 4.2, respectively. Results obtained by ESR (electron spin resonance) spectrometry confirmed the values of pH obtained with the microelectrode.

No abstract

To investigate the mechanism of trophoblast adhesion to fibronectin, we cultured blastocysts in serum-free medium on proteolytic fibronectin fragments containing its major functional domains, and localized fibronectin-binding integrins in outgrowing trophoblast cells by immunofluorescent staining. Outgrowth comparable to that obtained with intact fibronectin was observed using a 120 kD chymotryptic fragment containing the central cell-binding domain (FN-120) and the Arg-Gly-Asp (RGD) recognition sequence. A 40 kD COOH-terminal chymotryptic fragment of fibronectin containing both a heparin-binding region and an alternate (non-RGD) cell-binding site was inactive in supporting trophoblast adhesion. Three synthetic peptides derived from the heparin-binding domain, including the CS1 alternate cell-binding site, were also unable to promote trophoblast cell adhesion. A 75 kD recombinant protein, ProNectin F, containing 13 copies of the cell recognition epitope of fibronectin, Val-Thr-Gly-Arg-Gly-Asp-Ser-Pro-Ala-Ser, vigorously supported blastocyst outgrowth. Blastocyst outgrowth was not significantly different when surfaces were precoated with cellular fibronectin, which contains an alternatively spliced type III repeat and is the form actually encountered in vivo. Several putative fibronectin receptors were localized in trophoblast outgrowths by immunofluorescent labeling. Antibodies reactive with integrin subunits alpha 3, alpha 5, alpha IIb, alpha v, beta 1 and beta 3, but not alpha 4, all bound to trophoblast cells. Antibodies raised against either the beta 1 or beta 3 integrin subunits significantly inhibited fibronectin-mediated outgrowth. These findings demonstrate the key role of the central cell-binding domain of fibronectin in trophoblast adhesion, and suggest four RGD-binding integrins, alpha 3 beta 1, alpha 5 beta 1, alpha IIb beta 3, and alpha v beta 3, that could mediate trophoblast adhesion in vitro and may play an important role during implantation.

The role of transcriptional factor FOXO1 in the mechanism of drug-resistance in ovarian cancer has not been elucidated. In ovarian cancer cell lines, FOXO1 expression and its correlation with paclitaxel treatment was investigated by cytotoxic assay and silencing experiment. Clinical ovarian cancer samples were also examined for FOXO1 expression by immunohistochemistry. FOXO1 expression was distinctively upregulated in paclitaxel-resistant cell line, and enhanced by exposure to paclitaxel. FOXO1 overexpression was frequently observed in tissue samples from chemoresistant patients compared to chemosensitive patients. FOXO1 silencing in paclitaxel-resistant cell line decreased its resistance. Modification of oxidative stress by co-treatment with pharmacologic modulators of reactive oxygen species attenuated cytotoxicity of paclitaxel. Downstream targets of FOXO1 involving oxidative stress were also attenuated in silencing experiment, suggesting its involvement in altered sensitivity to paclitaxel. These results indicate that FOXO1 links to cytotoxic stress induced by paclitaxel and contributes to the drug-resistance in ovarian cancers.