Evaluation of 3,3'-diindolylmethane with gardasil quadrivalent HPV vaccine in K14-HPV16-transgenic mice cervical histology.

BACKGROUND: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

3,3'-Diindolylmethane increases serum interferon-γ levels in the K14-HPV16 transgenic mouse model for cervical cancer.

UNLABELLED: 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. MATERIALS AND METHODS: 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. RESULTS: 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). DISCUSSION: 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.

Results from a dose-response study using 3,3'-diindolylmethane in the K14-HPV16 transgenic mouse model: cervical histology.

The human papilloma virus is the major cause of cervical cancer. Viral infection initiates cervical intraepithelial neoplasia, which progresses through several stages to cervical cancer. The objective of this study is to identify the minimum effective dose of diindolylmethane that prevents the progression from cervical dysplasia to carcinoma in situ. We document cervical histology in K14-HPV16 mice receiving different doses of diindolylmethane. Urinary diindolylmethane concentrations are reported. Diindolylmethane could enhance the efficacy of human papilloma virus vaccines, creating a new therapeutic use for these vaccines in women already infected with the virus. Five doses (0-2,500 ppm) of diindolylmethane were incorporated into each mouse diet. The reproductive tract was serially sectioned and urine was obtained for analysis of urinary diindolylmethane. The results indicate that 62% of mice receiving 1,000 ppm diindolylmethane remained dysplasia-free after 20 weeks compared with 16% of mice receiving no diindolylmethane and 18% receiving 500 ppm; 1,000 ppm of 3,3'-diindolylmethane in the diet completely suppressed the development of cervical cancer. Urinary diindolylmethane levels increased significantly as diindolylmethane in food increased. These findings imply usefulness for diindolylmethane in the search to prevent cervical cancer when used in combination with prophylactic or therapeutic vaccines.

Diindolylmethane inhibits cervical dysplasia, alters estrogen metabolism, and enhances immune response in the K14-HPV16 transgenic mouse model.

This study was designed to establish whether 3,3'-diindolylmethane (DIM) can inhibit cervical lesions, alter estrogen metabolism in favor of C-2 hydroxylation, and enhance immune function in the K14-HPV16 transgenic mouse model. Mice were bred, genotyped, implanted with E(2) pellets (0.25 mg/90-day release) under anesthesia, and divided into groups. Wild-type and transgenic mice were given either AIN76A diet alone or with 2,000 ppm DIM for 12 weeks. Blood and reproductive tracts were obtained. Blood was analyzed for estrogen metabolites and IFN-gamma. The cervical transformation zone was sectioned and stained for histology. Estradiol C-2 hydroxylation and serum IFN-gamma levels were significantly increased over controls in wild-type and transgenic mice receiving DIM. In wild-type mice without DIM, hyperplasia of the squamous epithelium was observed. Wild-type mice fed DIM displayed a normal thin epithelium. In transgenic mice without DIM, epithelial cell projections into the stroma (papillae) were present. An additional degree of nuclear anaplasia in the stratum espinosum was observed. Dysplastic cells were present. Transgenic mice fed DIM displayed some mild hyperplasia of the squamous epithelium. DIM increases estrogen C-2 hydroxylation in this model. Serum INF-gamma was increased, indicating increased immune response in the DIM-fed animals. Histopathology showed a marked decrease in cervical dsyplasia in both wild-type and transgenic mice, indicating that DIM delays or inhibits the progression from cervical dysplasia to cervical cancer. Using the K14-HPV16 transgenic mouse model, we have shown that DIM inhibits the development of E6/E7 oncogene-induced cervical lesions.