Conversion of C57Bl/6 Mice from a Tumor Promotion-Resistant to a Sensitive Phenotype by Enhanced Ornithine Decarboxylase Expression

The study developed a transgenic mouse model to investigate the role of ornithine decarboxylase (ODC) in tumor promotion. By overexpressing ODC in hair follicle keratinocytes of C57Bl/6 mice using a tetracycline-regulated system, researchers found that high levels of ODC activity led to significant epidermal hyperplasia and increased sensitivity to tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA). This effect was reversible with doxycycline, which repressed transgene expression. The findings indicated that enhanced ODC expression converted the typically tumor-resistant C57Bl/6 mice to a tumor-sensitive phenotype, highlighting the potential role of ODC in tumor promotion.