A high-fat diet increases the incidence of mammary cancer inc-Ha-ras proto-oncogene transgenic rats.

Mammary cancer is the most common type of cancer and the fifth most common cause of cancer-related deaths among Japanese women. The recent sharp increase in the number of women diagnosed with mammary cancer per year is thought to be associated with increased fat intake resulting from changes in the dietary habits of contemporary Japanese citizens. In this study, human c-Ha-ras proto-oncogene transgenic (Hras128) rats, which are highly susceptible to mammary carcinogens, were fed high- or low-fat diets to examine the relationship between fat consumption and the development of mammary cancer. Female 7-week-old Hras128 rats and wild-type littermates were administered benzo[a]pyrene. A week later, the animals were randomly assigned to high-fat or low-fat diet groups (45% or 10% of calories from fat, respectively). After 12 weeks, the rats were sacrificed and autopsied, and mammary tumors were excised and processed for microscopic observation. Mammary tumors were found in 11 of the 12 animals in the high-fat diet group and in 5 of the 12 animals in the low-fat diet group, and the numbers of mammary gland tumors per animal in these groups were 1.7 and 0.7, respectively. Notably, the observed differences in incidence and multiplicity of mammary tumors between the two groups were statistically significant. These results suggest a positive relationship between the incidence of breast cancer and high fat intake.

Anticancer activities and mechanisms of Blumea balsamifera extract in hepatocellular carcinoma cells.

Blumea balsamifera (also known as sambong), a medicinal plant, is known to improve physiological disorders such as rheumatism and hypertension. However, its anticancer activity has not been well elucidated. In this study, we found that Blumea balsamifera MeOH extract (BME) induced growth inhibitory activity in rat and human hepatocellular carcinoma cells (McA-RH7777, HepG2, respectively) without cytotoxicity as in with rat hepatocytes used as a normal cell model. BME induced cell cycle arrest at G1 phase via decreases in expression of cyclin-E and phosphorylation of retinoblastoma (Rb) protein in both dose- and time-dependent manners. Furthermore, BME reduced the level of a proliferation related ligand (APRIL) which stimulates tumor cell growth. The anti-proliferative effect of BME was improved slightly but significantly by the treatment with recombinant human APRIL. These findings suggest that BME may have a possible therapeutic potential in hepatoma cancer patients and the depletion of cellular APRIL may be one of the important mechanisms on the growth inhibitory effect of BME.

Mechanism of growth inhibitory effect of Blumea balsamifera extract in hepatocellular carcinoma.

Blumea balsamifera is known to improve physiological disorders such as rheumatism and hypertension, but its anticancer activity has not been well elucidated. In this study, we found that Blumea balsamifera MeOH extract (BME) induced growth-inhibitory activity in rat and human hepatocellular carcinoma cells without cytotoxicity in rat hepatocytes which were used as a normal cell model. BME induced cell cycle arrest at the G1 phase via decreases in the expression of cyclin-E and phosphorylation of retinoblastoma protein. Furthermore, BME reduced the level of a proliferation-inducing ligand, that stimulates tumor cell growth. These findings suggest that BME has possible therapeutic potential in hepatoma cancer patients and that depletion of cellular APRIL is an important mechanism in the growth-inhibitory effect of BME.

Chemical constituents of cape aloe and their synergistic growth-inhibiting effect on Ehrlich ascites tumor cells.

The constituents of cape aloe were investigated after a preliminary screening of the growth-inhibiting effect on Ehrlich ascites tumor cells (EATC) of several extracts of this plant. Ten compounds were isolated from the dichloromethane (CH(2)Cl(2)) extract that showed the strongest activity, and their structures were elucidated as aloe-emodin (1), p-hydroxybenzaldehyde (2), p-hydroxyacetophenone (3), pyrocatechol (4), 10-oxooctadecanoic acid (5), 10-hydroxyoctadecanoic acid (6), methyl 10-hydroxyoctadecanoate (7), 7-hydroxy-2,5-dimethylchromone (8), furoaloesone (9), and 2-acetonyl-8-(2-furoylmethyl)-7-hydroxy-5-methylchromone (10) based on MS and various NMR spectroscopic techniques. Compounds 2-7 were isolated for the first time from cape aloe. Compounds 4-7 and 10 showed a significant growth-inhibiting effect, and compound 1 exhibited a remarkable synergistic effect on compounds 8-10, which was not observed with the treatment by each compound alone on EATC. These results suggest that the strong growth-inhibiting effect of the CH(2)Cl(2) extract was dependent not on one compound alone, but on the synergistic effect from the combination of compound 1 and the other compounds.

Mechanism of growth inhibitory effect of cape aloe extract in ehrlich ascites tumor cells.

Cape aloe (Aloe ferox Miller) has been a herb well known for its cathartic properties and has also been used popularly as a health drink (juice, tea and tonic) in the United States and in Europe. Cape aloe extract also has been reported to possess several pharmacological effects, such as anti-inflammatory, anti-bacterial, anti-fungal and protective effect against liver injury. However, the investigations on an anti-tumor activity in cape aloe extract are very few and subsequent mechanisms have not been well elucidated. In this study, we examined the effect of the selective growth inhibitory activity of cape aloe extract and found that the cape aloe extract, especially the dichloromethane (CH(2)Cl(2)) extract, caused a dose-dependent growth inhibitory effect in Ehrlich ascites tumor cells (EATC), but not in mouse embryo fibroblast (NIH3T3) cells, which was used as a normal cell model. Furthermore, the CH(2)Cl(2) extract caused an accumulation of cells in the G1 phase and a decrease of cells in the S and G2/M phase of the cell cycle and inhibited DNA synthesis in a dose-dependent manner. In addition, other results suggest that cell cycle arrest and inhibition of proliferation in EATC by the CH(2)Cl(2 )extract are associated with decreased retinoblastoma protein (Rb) phosphorylation.