The study used transgenic mice with targeted expression of spermidine/spermine N1-acetyltransferase (SSAT) in hair follicle keratinocytes to investigate susceptibility to skin cancer. These K6-SSAT transgenic mice, bred onto a tumor-resistant C57BL/6 background, showed a 10-fold increase in epidermal tumors when exposed to a carcinogenesis protocol involving 7,12-dimethylbenz[a]anthracene and 12-O-tetradecanoylphorbol-13-acetate. The transgenic mice exhibited elevated SSAT activity and protein levels, along with increased putrescine and N1-acetylspermidine, indicating enhanced polyamine catabolism. The study concluded that this activation of polyamine catabolism might play a crucial role in chemically induced skin cancer, as evidenced by the early onset and progression to carcinomas in the transgenic mice.
54 citations,
May 2001 in “Journal of Investigative Dermatology” 43 citations,
February 1999 in “Biochemical Journal” The study involved generating a transgenic mouse line overexpressing the SSAT gene under a mouse metallothionein I promoter, leading to significant changes in tissue polyamine pools and delayed permanent hair loss compared to previous models. The liver was notably affected, with altered polyamine levels. Despite high SSAT mRNA levels, enzyme activity was only moderately increased unless induced by ZnSO4 or the polyamine analogue DENSPM, which caused a dramatic increase in enzyme activity and depletion of liver polyamines, resulting in high mortality and liver damage. The findings suggested that SSAT overexpression made the mice highly sensitive to polyamine analogues, indicating a post-transcriptional regulation mechanism.
233 citations,
July 1997 in “PubMed” In this study, researchers investigated whether overexpression of ornithine decarboxylase (ODC) was sufficient for tumor promotion in mouse skin. They used transgenic mice with high ODC expression in epidermal keratinocytes and found that these mice were more sensitive to carcinogen initiation compared to controls. Notably, mice with ODC overexpression in hair follicle keratinocytes developed tumors without the need for additional tumor promoters. The study concluded that ODC overexpression was sufficient to activate target cells in hair follicles, leading to clonal expansion and epidermal tumor formation, indicating that hair follicles are key sites for chemical carcinogen targeting in the skin.
