Gene expression profiling of altered NF-kB p65 ser536 phosphorylation in prostate cancer cells

Aberrant regulation of NF-kB pathway is believed to be a major event contributing to malignant transformation and progression of prostate cancer (PCa). P65 consists of a DNA-binding and dimerization domain (RHD), nuclear localization signal (NLS) and transactivation domains (TA1 and TA2). The c-terminal 30 amino acids (TA1 domain) comprise the most important transactivation domain and NF-kB transactivation may be regulated by multiple phosphorylation in this domain. This p536 is located in TA1 domain and is conserved in human, mouse, chicken. We previously discovered that p536 is present in majority of PCa and associated with ERG expression indicating that ERG can significantly enhance phosphorylation of p65 at Ser536 in vivo. We have successfully generated a dominant negative (DN) p65 which has been mutated (S536A) such that it cannot be phosphorylated at Ser 536 and cannot carry out Ser536 phosphorylation dependent functions. We also generated two mutants S536D and S536E which are the phosphomimetic mutant that resembles phospho-p65 and can be detected by anti-phospho-p65 antibody. We carried out microarray studies and discovered a set of p536 regulated genes compared with wild type p65 regulated gene set. We established PNT1a stable cell lines expressing WT p65, S536E (active p536), S536A (DN p635) or control (pCDH). Groups were profiled for gene expression.