Preventive effects of glycyrrhizin on estrogen-related endometrial carcinogenesis in mice.

We have previously reported on the inhibitory effect of Glycyrrhizae radix (Gl radix) on mouse endometrial carcinogenesis. The present study was performed to clarify the effects of Gl radix and glycyrrhizin (GL), the main part of Gl radix, on estradiol (E2)-related endometrial carcinogenesis. Both Gl radix and GL exerted a significant decrease in the COX-2, IL-1alpha and TNF-alpha mRNA expressions. GL generated a significant decrease in the incidence of endometrial adenocarcinoma. Accordingly, the preventive effects of Gl radix may be attributable to GL, thus being related with the suppression of COX-2, IL-1alpha and TNF-alpha. Gl radix and GL could therefore be a promising formula for the chemoprevention of human endometrial cancer.

Inhibitory effects of Hochu-ekki-to on endometrial carcinogenesis induced by N-methyl-N-nitrosourea and 17beta-estradiol in mice.

An evaluation of the effects of a traditional Chinese herbal medicine, Hochu-ekki-to (Bu-zong-yi-qi-tang) on endometrial carcinogenesis was performed in experiments with female mice. In the short-term experiment, dietary exposure of Hochu-ekki-to (0.2% for 2 weeks) decreased the estradiol-17beta (E2)-stimulated expression levels of c-jun (P<0.001), tumor necrosis factor (TNF)-alpha (P<0.005), estrogen receptors (ER)-alpha (P<0.001) and ER-beta (P<0.005), as determined by reverse transcription-polymerase chain reaction and a Southern blot analysis in the uteri of the ovarectomized mice. In the long-term experiment, the mice were given N-methyl-N-nitrosourea (MNU) solution (1 mg/100 g body weight) and normal saline (as controls) into their left and right uterine corpora, respectively, and then were divided into four groups. Group 1 (25 mice) was given a diet with Hochu-ekki-to and 5 ppm E2. Group 2 (25 mice) was given a diet with E2 alone. Group 3 (25 mice) was given a diet with Hochu-ekki-to alone. Group 4 (25 mice) was kept on the basal diet alone and treated as a control. The incidence of uterine endometrial cancer in the group with Hochu-ekki-to treatment was substantially lower than of the control group. The inhibitory effect of Hochu-ekki-to on endometrial carcinogenesis is thus suggested to decrease the expressions of c-jun, TNF-alpha, ER-alpha and -beta.

Anti-tumor effects of herbal medicines on endometrial carcinomas via estrogen receptor-alpha-related mechanism.

This study was performed to examine the relationship between the anti-tumor effects of herbal medicine and endometrial carcinoma with ER-related mechanisms. An endometrial cancer cell line (Ishikawa) was used for this study. The cell viability and expression of estrogen receptors (ER) were determined by MTT and RT-PCR. A dose-dependent decrease of viability and apoptosis of the cancer cells was generated by exposure to the herbal medicines, Juzen-taiho-to or Shimotsu-to. The expression of ER-alpha mRNA, but not ER-beta mRNA was suppressed by Juzen-taiho-to or Shimotsu-to in an endometrial cancer cell line. The anti-tumor effect of these herbal medicines against endometrial carcinoma might be correlated to the ER-alpha related mechanism.

Preventive effect of Juzen-taiho-to on endometrial carcinogenesis in mice is based on Shimotsu-to constituent.

Juzen-taiho-to, a Kampo formula, originally consists of a mixture of Shimotsu-to and Shikunshi-to formulas together with two other crude ingredients. Juzen-taiho-to is reported to have a preventive effect on endometrial carcinogenesis in mice. Shimotsu-to exerts an inhibitory effect on estrogen-induced expression of c-fos, interleukin (IL)-1alpha and tumor necrosis factor (TNF)-alpha in uteri of ovarectomized mice. In the present study, short- and long-term experiments were designed to determine the effects of Juzen-taiho-to and Shimotsu-to on the estrogen-related endometrial carcinogenesis in mouse uteri, associated with the expression of cyclooxygenase (COX)-1 and -2. In the short-term experiment, exposure to Juzen-taiho-to or Shimotsu-to significantly reduced estradiol-17beta (E(2))-stimulated expressions of COX-2 mRNA (p<0.05) as well as the protein. However, no effects on the expression of COX-1 were observed. Shikunshi-to did not affect COX expression. In the long-term experiment, 90 female ICR mice were given N-methyl-N-nitrosourea (MNU) into their uterine corpora. The animals were divided into four groups as follows: group 1, a diet containing 0.07% Shimotsu-to and 5 ppm E(2); group 2, a diet containing 5 ppm E(2); group 3, a diet containing 0.07% Shimotsu-to; group 4 served as a control. Exposure of Shimotsu-to reduced the incidence of MNU- and E(2)-induced endometrial adenocarcinoma and atypical hyperplasia at the termination of the experiment (30 weeks). The above findings and our previous reports suggest that Shimotsu-to is responsible for the preventive effects of Juzen-taiho-to on estrogen-related endometrial carcinogenesis in mice, through the inhibition of estrogen-related COX-2 as well as c-fos, IL-1alpha and TNF-alpha expressions.

Association of cellular apoptosis with anti-tumor effects of the Chinese herbal complex in endocrine-resistant cancer cell line.

We previously reported the special herbal complex (Hoelen, Angelicae radix, Scutellariae radix and Glycyrrhizae radix) suppressed telomerase activity in chemo-endocrine-resistant cancer cell lines. The present study attempted to determine whether the above herbal complex induces apoptosis in endocrine-resistant AN3CA and adriamycin-resistant MCF7/ADR carcinoma cells. Exposure to the herbal complex decreased cell viability in a time- and dose-dependent manner in the 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. The agent induced cellular apoptosis was determined by DNA fragmentation and a nuclear staining assay. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) showed the decreased expression of apoptosis-related genes, bcl-2, c-myc and human telomerase catalytic subunit (hTERT). A decreased protein level of bcl-2 and c-myc was also determined by Western blot analysis. The data imply that the decreased expression of the genes via suppressing telomerase activity is involved in cellular apoptosis in endocrine-resistant AN3CA cells. Thus, it is suggested that the special herbal complex may be a promising candidate for the treatment of endocrine-resistant gynecologic carcinomas.

Shimotsu-to is the agent in Juzen-taiho-to responsible for the prevention of endometrial carcinogenesis in mice.

We have found that Juzen-taiho-to has a preventive effect on endometrial carcinogenesis in mice (Carcinogenesis 22 (2001) 587). In the present study, the constituents of Juzen-taiho-to responsible for this effect were explored using a short-term experiment. Thirty female ICR mice were divided into five groups: Group 1 was given a diet containing 0.2% of Juzen-taiho-to and 5ppm estradiol-17beta (E(2)); Group 2 was given a diet containing Shimotsu-to (0.07%) and E(2) (5ppm); Group 3 received Shikunshi-to (0.08%) and E(2) (5ppm) in the diet; Group 4 was given 5ppm E(2) in the diet; and Group 5 served as a control. Exposure of Juzen-taiho-to or Shimotsu-to decreased E(2)-stimulated expression of estrogen-related gene c-fos mRNA (P<0.05), and the cytokines interleukin-1alpha mRNA and tumor necrosis factor alpha mRNA P<0.01). A similar trend was not found upon treatment with Shikunshi-to. These findings suggest that Shimotsu-to is responsible for the inhibitory effects of Juzen-taiho-to on the estrogen-related endometrial carcinogenesis in mice.