Antitumorigenic Effects of Tamoxifen, Raloxifene and the Combination on the Development of Breast Tumors Induced by Mouse Mammary Carcinoma Cells in Balb/c-J Female Mice

Abstract

The antitumorigenic efficacy of tamoxifen, raloxifene, and their combination was evaluated on 4t1 estrogen-positive murine mammary carcinoma cells by determining their ability in breast tumor development in Balb/c-J female mice. Each mouse received intraperitoneally 0.1 ml of PBS solvent containing no drug, 12 mg (0.6 mg/kg) of tamoxifen, 36 mg (1.8 mg/kg) of raloxifene, or the combination of the two drugs (12 mg tamoxifen + 36 mg raloxifene) at 48-hour intervals for 35 days. Drug concentrations used were equivalent to human doses. Within the study period of 35 days, tamoxifen demonstrated the greatest effectiveness, as it allowed “progression-free survival,” increased mouse life span by an average of 6 days, had the greatest number of survivors (90.9%), and those with the smallest spleen weight and volume. Raloxifene and combination groups, compared to the drug-untreated mice, did not significantly lengthen the life span or survivability, produced grossly enlarged spleens, and mice exhibited maladies such as leg paralysis and acute lethargy.

Keywords:

• Mouse breast cancer cells (4t1)
• tamoxifen
• raloxifene
• drug combination