Altered cellular proton handling and cell volume regulation are hallmarks of tumorigenesis[1]. In normal rodent prostate tissue ATP12A functions to acidify the prostate fluid and semen [2]. Given its function in the normal prostate and its altered expression during apoptosis and in cancer cells, it is feasible to assume that ATP12A expression is also deranged in pathological prostate tissue. We therefore performed immunohistochemistry of ATP12A in formalin-fixed, paraffin-embedded histological sections from human prostate lesions. Normal prostate tissue displayed a membrane-bound ATP12A staining with focal accumulated pattern, whereas in the benign hyperplasia and cancerous tissue the protein appears to be displaced in the luminal cells of the glandular epithelium. To test for altered gene expression we performed reverse-transcriptase quantitative PCR (RT-qPCR) in normal (tumor-free) prostate tissue, benign prostate hyperplasia (BPH) and tumor stages I-III using cDNA from a prostate cancer disease array (OriGene Technologies). As a result no significantly different expression levels could be detected in the various disease states compared to normal tissue, which contrasts the findings from immunohistochemistry and points to the possibility of altered post-translational processing and/or sorting of the protein. ATP12A is also expressed at different levels in PC-3- and LNCaP prostate cancer cells, being more abundantly expressed in the latter cells. In conclusion, ATP12A is expressed in normal and pathological prostate tissue as well as in PC-3- and LNCaP prostate cancer cells with a significant ~26-fold higher expression in the latter cell type. Protein expression in these tumor cell lines was verified by Western blot.

1.Gatenby, R.A., et al.,Br J Cancer, 2007.97(5): p. 646–53.

2. Pestov, N.B., et al., Am J Physiol Cell Physiol, 2002.282(4): p. C907–16.