Chemopreventive Effects of Rexinoid Bexarotene, Tyrosine Kinase Inhibitor Gefitinib, and Celecoxib on Mammary Tumor Development

Researchers at Baylor College of Medicine have conducted a study to evaluate the chemopreventive effects of three agents, rexinoid bexarotene, tyrosine kinase inhibitor gefitinib, and celecoxib, on mammary tumor development in p53-null mammary epithelium. The study found that rexinoid bexarotene was the most efficacious inhibitor, reducing mammary tumor development by 75% in virgin mice and significantly delaying mean tumor development by 98 days in hormone-stimulated mice. In contrast, tyrosine kinase inhibitor gefitinib reduced mammary tumor incidence by 50% in virgin mice but did not significantly delay mean tumor latency in hormone-stimulated mice. Celecoxib did not show any significant chemopreventive effects in either model. The researchers concluded that the agents should be compared with tamoxifen, which has shown superior results in preventing tumor development in p53-null mammary cells.

Key Takeaways:

• Rexinoid bexarotene was the most efficacious inhibitor, reducing mammary tumor development by 75% in virgin mice and significantly delaying mean tumor development by 98 days in hormone-stimulated mice.
• Tyrosine kinase inhibitor gefitinib reduced mammary tumor incidence by 50% in virgin mice but did not significantly delay mean tumor latency in hormone-stimulated mice.
• Celecoxib did not show any significant chemopreventive effects in either model.
• The researchers concluded that the agents should be compared with tamoxifen, which has shown superior results in preventing tumor development in p53-null mammary cells.
• The study compared the results of the p53 model with other transgenic models to show that mammary tumors arising from different oncogenic events will respond differently to the different agents.
• The study highlights the potential of rexinoid bexarotene as a chemopreventive agent in preventing mammary tumor development.

Statistics:

• Rexinoid bexarotene reduced mammary tumor development by 75% in virgin mice.
• Tyrosine kinase inhibitor gefitinib reduced mammary tumor incidence by 50% in virgin mice.
• Rexinoid bexarotene significantly delayed mean tumor development by 98 days in hormone-stimulated mice.
• Celecoxib did not show any significant chemopreventive effects in either model.
• The study compared the results of the p53 model with other transgenic models.

Sources:

• D. Medina et al. "Prevention of Tumorigenesis in p53-Null Mammary Epithelium by Rexinoid Bexarotene, Tyrosine Kinase Inhibitor Gefitinib, and Celecoxib." Cancer Prevention Research, 2009;2(2):168-174.
• American Association Cancer Research. Cancer Prevention Research.