Decrease of cellular
zinc in the epithelium of the prostate has been implicated in the development of
prostate cancer. To investigate whether ZnT7, a
zinc transporter involved in intracellular
zinc accumulation, played a role in
prostate cancer development, we generated and characterized a transgenic
adenocarcinoma mouse prostate (TRAMP) model with a Znt7-null genetic background. TRAMP mice (TRAMP/Znt7(-/-) and TRAMP/Znt7(+/+)) were euthanized at 6, 8, 16, and 28 weeks of age for histopathological analysis of the prostates and for the presence of prostate
tumors and
metastasis. At 6 and 8 weeks of age, TRAMP/Znt7(-/-) mice displayed higher frequencies of low grade
prostatic intraepithelial neoplasia (PIN) and high grade PIN, respectively, in the prostates than the age-matched TRAMP/Znt7(+/+) mice. At 16 weeks of age, 33% TRAMP/Znt7(-/-) mice had prostate
tumors and one half of the mice with prostate
tumors had
tumor metastasized to the draining lymph nodes while no prostate
tumor was detected in the control TRAMP mice. By 28 weeks, 67% TRAMP/Znt7(-/-) mice developed prostate
tumors while only 22% control TRAMP mice had prostate
tumors. Furthermore, apoptosis was reduced in the prostates of TRAMP/Znt7(-/-) mice. In conclusion, a null-mutation of the Znt7 gene accelerates prostate
tumor formation in TRAMP mice.