Yoshiko Satomi

Cancer prevention by carotenoids

Various natural carotenoids seem to be valuable for cancer prevention, and these carotenoids may be more suitable in combinational use, rather than in single use. In fact, we have proven that combinational use of natural carotenoids resulted in significant suppression of liver cancer. Patients of viral hepatitis with cirrhosis were administered with beta-cryptoxanthin-enriched Mandarin orange juice, in addition to capsules of carotenoids mixture. Cumulative incidence of hepatocellular carcinoma development was compared with that in the group treated with carotenoids mixture capsules alone, or in the group without treatment (control group). In the data analysis at year 2.5, cumulative incidence of liver cancer in beta-cryptoxanthin-enriched orange juice with carotenoids mixture capsules-treated group was lower than that in the control group (p=0.05). Cumulative incidence of liver cancer in the group treated with carotenoids mixture capsules alone was also lower than that in the control group, but not statistically significant.

Isoliquiritigenin inhibits the growth of prostate cancer.

OBJECTIVE Isoliquiritigenin, one of the components in the root of Glycyrrhiza glabra L., is a member of the flavonoids, which are known to have an anti-tumor activity in vitro and in vivo. In this study, we investigated the anti-tumor effect of isoliquiritigenin on prostate cancer in vitro. METHODS DU145 and LNCaP prostate cancer cell lines were used as targets. We examined the effects of isoliquiritigenin on cell proliferation, cell cycle regulation and cell cycle-regulating gene expression. Further, we investigated the effects of isoliquiritigenin on the GADD153 mRNA and protein expression, and promoter activity. RESULTS Isoliquiritigenin significantly inhibited the proliferation of prostate cancer cell lines in a dose-dependent and time-dependent manner. Fluorescence-activated cell sorting (FACS) analysis indicated that isoliquiritigenin induced S and G2/M phase arrest. Isoliquiritigenin enhanced the expression of GADD153 mRNA and protein associated with cell cycle arrest. Further, isoliquiritigenin stimulated transcriptional activity of GADD153 promoter dose-dependently. CONCLUSION These findings suggest that isoliquiritigenin is a candidate agent for the treatment of prostate cancer and GADD153 may play an important role in isoliquiritigenin-induced cell cycle arrest and cell growth inhibition.

Inhibition of initiation and early stage development of aberrant crypt foci and enhanced natural killer activity in male rats administered bovine lactoferrin concomitantly with azoxymethane

The influence of concomitant administration of bovine lactoferrin (bLF) on induction of aberrant crypt foci (ACF) by azoxymethane was investigated in male F344 rats. Two percent bLF and 3% Bifidobacterium longum (B. longum), as a positive control, significantly decreased the numbers of ACF as well as the total numbers of aberrant crypts reproducibly in three independent studies (2% bLF, P < 0.01; 3% B. longum, P < 0.05). Most importantly large size foci composed of four or more crypts were always significantly decreased by 2% bLF (P < 0.05). Additional investigation of the natural killer activity of spleen cells demonstrated enhancement by bLF (P < 0.01) and B. longum (P < 0.01) in line with the levels of influence on foci induction, indicating a possible role for elevated immune cytotoxicity in the observed inhibition.

Cancer Prevention by Phytochemicals

Information has been accumulated indicating that diets rich in vegetables and fruits can reduce the risk of a number of chronic diseases, including cancer, cardiovascular disease, diabetes and age-related macular degeneration. Phytochemicals (various factors in plant foods), such as carotenoids, antioxidative vitamins, phenolic compounds, terpenoids, steroids, indoles and fibers, have been considered responsible for the risk reduction. Among them, a mixture of natural carotenoids has been studied extensively and proven to show beneficial effects on human cancer prevention.

Cancer control by phytochemicals.

Chemoprevention is one of the most important strategy in the field of cancer control. Molecular mechanism-based cancer chemoprevention by phytochemicals seems to be very attractive method. In this review, possible molecular targets for cancer prevention are overviewed, and some examples of cancer preventive phytochemicals, such as carotenoids, are presented.The short chain fatty acid valproic acid (VPA, 2-propylpetanoic acid) is approved for the treatment of epilepsia, bipolar disorders and migraine and clinically used for schizophrenia. In 1999, the first clinical anti-cancer trial using VPA was initiated. Currently, VPA is examined in numerous clinical trials for different leukaemias and solid tumour entities. In addition to clinical assessment, the experimental examination of VPA as anti-cancer drug is ongoing and many questions remain unanswered. Although other mechanisms may also contribute to VPA-induced anti-cancer effects, inhibition of histone deacetylases appears to play a central role. This review focuses on recent developments regarding the anti-cancer activity of VPA.

Implication of mitogen-activated protein kinase in the induction of G1 cell cycle arrest and gadd45 expression by the carotenoid fucoxanthin in human cancer cells

BACKGROUND The precise mechanism of the anti-tumor action of fucoxanthin has yet to be elucidated. We previously reported that gadd45a and gadd45b might play a role in the G1 arrest induced by fucoxanthin. In the present study, we show that several MAPKs modulate the induction of gadd45 and G1 arrest METHODS HepG2 and DU145 cells were used. The cell cycle was analyzed using flow cytometry. Expression of gadd45 was assayed by Northern blot and/or quantitative RT-PCR analyses. Activation of MAPK was assayed by Western blot analysis. RESULTS Inhibition of p38 MAPK enhanced the induction ofgadd45a expression and G1 arrest by fucoxanthin in HepG2 cells. Inhibition of ERK enhanced gadd45b expression but had no effect on the induction of G1 arrest by fucoxanthin in HepG2 cells. Inhibition of SAPK/JNK suppressed the induction of gadd45a expression and G1 arrest by fucoxanthin in DU145 cells. These data suggest that gadd45a is closely related with the G1 arrest induced by fucoxanthin, and that the pattern of MAPK involvement in the induction of gadd45a and G1 arrest by fucoxanthin differs depending on the cell type. GENERAL SIGNIFICANCE The implication of GADD45 and MAPK involvement in the anti-tumor action of carotenoids is first described.

Genistein induces Gadd45 gene and G2/M cell cycle arrest in the DU145 human prostate cancer cell line.

Genistein is the most abundant isoflavone of soybeans and has been shown to cause growth arrest in various human cancer cell lines. However, the precise mechanism for this is still unclear. We report here that the growth arrest and DNA damage‐inducible gene 45 (gadd45) gene is induced by genistein via its promoter in a DU145 human prostate cancer cell line. The binding of transcription factor nuclear factor‐Y to the CCAAT site of the gadd45 promoter appears to be important for this activation by genistein.

Steroidal saponins from the underground parts of Chlorophytum comosum and their inhibitory activity on tumour promoter-induced phospholipids metabolism of hela cells

Three new spirostanol pentaglycosides embracing beta-D-apiofuranose were isolated from the fresh underground parts of Chlorophytum comosum together with four known saponins. The structures of new compounds were determined by spectroscopic data, including two-dimensional NMR, and partial acid-catalysed hydrolysis to be (25R)-5 alpha-spirostane-2 alpha,3 beta-diol 3-O-[O-beta-D-glucopyranosyl- (1-->2)-O-[O-beta-D-apiofuranosyl-(1-->4)-beta-D-glucopyranosyl-(1 -->3)]-O- beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside], (25R)-3 beta-hydroxy-5 alpha-spirostan-12-one (hecogenin) 3-O-[O-beta-D-glucopyranosyl-(1-->2)-O-[O-beta-D-apiofuranosyl-(1- ->4)- beta-D-xylopyranosyl-(1-->3)]-O-beta-D-glucopyranosyl-(1-->4)-beta-D- galactopyranoside] and hecogenin 3-O-[O-beta-D-glucopyranosyl-(1-->2)-O-[O-beta-D- apiofuranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)]-O-beta-D-gluc opyranosyl- (1-->4)-beta-D-galactopyranoside], respectively. The isolated saponins were examined for inhibitory activity using 12-O-tetradecanoylphorbor-13-acetate-stimulated 32P-incorporation into phospholipids of HeLa cells as the primary screening test to identify new antitumour-promoter compounds.

Relationship between postrenal transplant osteonecrosis of the femoral head and gene polymorphisms related to the coagulation and fibrinolytic systems in Japanese subjects.

Background. Nontraumatic osteonecrosis of the femoral head (ONFH) is one of the complications that may occur after renal transplantation. We investigated the relationship between the incidence of ONFH and polymorphisms in the genes for plasminogen activator inhibitor (PAI)-1, which is one of the major regulatory proteins of the fibrinolytic system, and 5,10-methylenetetrahydrofolate reductase (MTHFR), which is associated with the plasma levels of homocysteine in Japanese subjects. Methods. Thirty-one patients with postrenal transplant ONFH and 106 patients without ONFH were selected. Genotypes of PAI-1 4G/5G and MTHFR C677T were determined by direct sequencing of genomic DNA. In addition, plasma PAI-1 antigen (Ag) levels and plasma total homocysteine (tHcy) levels at the steady state were measured. The relationships between the incidence of ONFH and these genotypes, as well as plasma levels of the gene products, were investigated. Results. Plasma PAI-1 Ag levels were the highest in patients with the 4G/4G genotype, and plasma tHcy levels were the highest in patients with TT genotypes of MTHFR C677T. However, the relationship between the incidence of ONFHH and PAI-1 4G/5G or MTHFR C677T was not observed. The relationship between the incidence of ONFH and plasma levels of PAI-1 Ag or tHcy was not observed. Conclusions. Genotypes of PAI-1 4G/5G and MTHFR C677T or plasma concentrations of PAI-1 Ag and tHcy had no effect on the incidence of ONFH in Japanese subjects, unlike the results of studies performed in white subjects. The effect of genetic background on the pathologic conditions that developed in patients with postrenal transplant ONFH may differ according to race.

Antitumor-Promoting Activity of Scopadulcic Acid B, Isolated from the Medicinal Plant Scoparia dulcis L.

Scopadulcic acid B (SDB), a tetracyclic diterpenoid isolated from a medicinal plant, Scoparia dulcis L., inhibited the effects of tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in vitro and in vivo; SDB inhibited TPA-enhanced phospholipid synthesis in cultured cells, and also suppressed the promoting effect of TPA on skin tumor formation in mice initiated with 7,12-dimethylbenz[a]anthracene. The potency of SDB proved to be stronger than that of other natural antitumor-promoting terpenoids, such as glycyrrhetinic acid.