H. Leon Bradlow

While there is a large volume of literature describing a role for obesity as a risk factor for breast cancer and many other cancers, in the main a causal relationship has not been established. If the study is limited to breast cancer risk, it has been suggested that the increase in sex steroid formation that occurs in postmenopausal women plays a role. Obesity is known to be associated with chronic low grade inflammation, but no reason for this association has been offered in the past. The gut microbiome, while known to be enormous, has not in the past been considered as a metabolic role player in the body. This is now recognized to be the case. Recent studies have found the obesity is correlated with an alteration in the gut microbiome. In obese individual there is a change in the relative proportions of the two major classes of bacteria – bacteroides and firmacutes – with the latter dominant in obesity and resulting in the formation of increased amounts of metabolic endotoxins like deoxycholic acid and lipopolysaccharides (LPS). Obese individuals show a decrease in the concentration of Akkermansia muciniphila in the mucus that lines the intestinal wall, resulting in thinner mucus and a weakened intestinal lining and permitting metabolic endotoxins formed by other bacterial flora like LPS to enter the blood steam and cause the chronic inflammation associated with obesity. The change in the microbiome profile results in increases in bacterial strains that are more efficient at generating energy, leading to increased obesity. In mice, it has been shown that introducing gut bacterial flora from the cecum of obese mice into germ-free mice results in increased obesity with lesser food consumption while the reverse, introducing bacterial flora from lean mice results in a loss in weight. This raises the attractive possibility that manipulating the gut microbiome could facilitate weight loss or prevent obesity in humans.

Chemo-endocrine therapy for estrogen receptor positive (ER⁺) breast cancer exhibits acquired tumor resistance. Herbal medicines provide integrative support for breast cancer patients. Present study compared the efficacy of aqueous extracts from Lycium barbarum bark (LBB) and Lycium barbarum fruit (LBF) on ER⁺ MCF-7 cells. Cellular growth and 17ß-estradiol (E₂) metabolism quantified the efficacy. MCF-7 cells maintained in serum depleted medium+ E₂ exhibited increased anchorage-dependent and anchorage-independent growth. LBB exhibited greater potency than LBF (95% reduction in IC₅₀). LBB produced a 6.8-fold increase, 40% decrease, and a 3.7-fold increase in 2-hydroxyestrone (2-OHE₁), 16α-hydroxyestrone (16α-OHE₁), and estriol (E₃) formation. The corresponding values for LBF were 3.9, 33, and 10.5. LBB produced a16.3-fold and a twofold increase in 2-OHE₁:16α-OHE₁ and E₃:16α-OHE₁ ratios, whereas LBF produced a sixfold and a 2.9-fold increase. The efficacy of LBB is due to increased 2-OHE₁ formation, whereas that of LBF is due to accelerated conversion of 16α-OHE₁ to E₃. Specific growth inhibitory profiles of LBB and LBF may be due to their distinct chemical composition and their complementary actions on E₂ metabolism. This study validates a mechanistic approach to identify efficacious herbal extracts for clinical ER⁺ breast cancer.

The effects of 3,3'-diindolylmethane (DIM) together with the Gardasil vaccine on cervical histology were evaluated using the K14-HPV16-transgenic mouse model. The possibility that DIM could enhance the efficacy of this preventive vaccine in this model was explored. Transgenic mice were given 1000 mg/kg of DIM in the diet for 28 weeks. The mice were injected with Gardasil Quadrivalent HPV vaccine. Some mice were sacrificed at 28 weeks. Other groups were removed from the DIM diet after 28 weeks to a diet with no DIM for either 4 or 8 weeks. Cervical histology indicated that a high percentage of transgenic mice fed DIM and vaccinated with Gardasil manifested normal cervical epitheliums at 4 weeks after DIM discontinuation. Vaccination pre-supplemented with DIM may provide with a window of protection of at least four weeks in this transgenic model. However, extrapolation to the effect in humans is beyond the limited scope of the histological data presented here.

Studies have shown associations of diabetes and endogenous hormones with exposure to a wide variety of organochlorines. We have previously reported positive associations of polychlorinated biphenyls (PCBs) and inverse associations of selected steroid hormones with diabetes in postmenopausal women previously employed in a capacitor manufacturing plant.

While cervical cancer incidence and mortality rates have declined in the United States, this cancer represents a worldwide threat. Human papilloma viral infection causes cervical neoplasia (CIN). 3,3'-Diindolylmethane (DIM) prevents or inhibits the progression from cervical dysplasia to cancer. The aim of this study is to determine the most effective dose of DIM given continuously in food, that significantly increases serum interferon gamma levels (IFN-γ) in the K14-HPV16 transgenic mouse model for cervical cancer. Five doses of DIM in food were administered to the mouse model for 20 weeks. Serum Interferon gamma (IFN-γ) levels and estrogen metabolite levels were quantified. At 1000 ppm DIM, serum IFN-γ concentrations were significantly increased (p<0.0396). The estrogen metabolites were unchanged. IFN-γ concentrations in CIN free mice and the percentage of CIN free transgenic mice were well correlated (r=0.88). Significant increases in IFN-γ serum concentrations that correlate with the percentage of CIN free mice in each group indicate that 1000 ppm of DIM in food may be the most effective dose for future studies. These results may eventually lead to new and effective vaccination strategies in women already infected with the human papilloma virus.

Selective estrogen receptor modulators and a combination of mechanistically distinct chemotherapeutic agents represent conventional therapeutic interventions for estrogen receptor-positive (ER+) clinical breast cancer. Long-term treatment with these agents is associated with acquired tumor resistance and other adverse side effects that impact on patient compliance. Herbal medicines are being widely used in complementary and alternative medicine. However, long-term safety and efficacy of the use of herbal medicines, as well as their interaction with conventional endocrine and chemotherapeutic drug regimens remain largely unknown. The present study utilized a human cell culture model for ER+ clinical breast cancer to examine the potential therapeutic efficacy of an aqueous extract prepared from the fruit of popular Chinese herb Cornus officinalis (CO), also known as Fructus cornii. The human mammary carcinoma-derived MCF-7 cell line represented the model. Status of anchorage-independent growth and cellular metabolism of 17β-estradiol (E₂) represented the quantitative end-point biomarkers for efficacy. MCF-7 cells adapted for growth in serum-depleted medium (0.7% serum, <1 nM E₂) retained their endocrine responsiveness as evidenced by growth promotion by physiological levels of E₂, and growth inhibition by the selective ER modulator tamoxifen at the clinically achievable concentrations. Treatment of MCF-7 cells with CO resulted in inhibition of E₂-stimulated growth in a dose-dependent manner. Similarly, CO treatment also produced a dose-dependent progressive reduction in the number of anchorage-independent colonies, indicating effective reduction of the carcinogenic risk. Treatment of MCF-7 cells with CO at a maximally effective cytostatic concentration resulted in a 5.1-fold increase in the formation of the anti-prolifertive E₂ metabolite 2-hydoxyestrone (2-OHE₁), a 63.6% decrease in the formation of the pro-mitogenic metabolite 16α-hydroxestrone (16-αOHE₁) and a 9.1% decrease in the formation of mitogenically inert metabolite estrone (E₃). These alterations led to a 14.5-fold increase in the 2-OHE₁:16α-OHE₁, and a 3.3-fold increase in the E₃:16α-OHE1 ratios. These data validate a rapid cell culture-based mechanistic approach to prioritize efficacious herbal medicinal products for long-term animal studies and future clinical trials on ER+ clinical breast cancer.

The role of body fat as a risk factor for breast cancer has been well established. A decrease in the urinary 2/16α-hydroxyestrone ratio has also been shown to be a risk marker for breast cancer. These two observations are connected by the fact that obese women have decreased levels of 2-hydroxyestrone. To test the hypothesis that fat depots secrete factors that inhibit 2-hydroxylation, the effect of substances released into the media from adipocytes incubated in Krebs-Ringer buffer, on estrogen metabolism by MCF-7 cells in minimum essential medium eagle (MEM) plus adipocyte-conditioned media (ACM) was studied. The 1:1 ACM-MEM culture system resulted in a substantial and highly significant decrease in 2-hydroxylation of estradiol. This inhibition was partially reversed by the addition of indole-3-carbinol, a potent inducer of 2-hydroxylation of estradiol. Centrifugal sizing showed that the active 2-hydroxylation inhibitor in the medium had a molecular weight of about 30 kDa. These results suggest a mechanism for the decrease in 2-hydroxylation of estradiol that is observed in obese women and the increase in 2-hydroxylation observed in women with depleted fat depots.