Approximately 50% of all mammalian bioactive peptides require a C-terminal ?-amide moiety for full biological activity. This post-translationa modification requires the sequential enzyme reactions of PHM and PAL domains of bifunctional PAM. Dysregulated peptide amidation by PAM, either overexpression or impairment, is problematic. The upregulation of PAM is observed in a number of cancers, where the amidated peptide hormones serve as autocrine and/or paracrine growth factors facilitating tumor growth. This proposal has selected androgen independent prostate cancer (AI CaP) as a proof-of-concept study to development a platform technology directed towards the rational therapeutic targeting and early detection protocols of cancers that utilize PAM for progression. The contemporary treatment for late stage CaP is an androgen-ablative therapy. Following therapeutic hormone deprivation, cells in the prostate differentiate, increasing the neuroendocrine populations (which contain PAM). Selection towards the androgen-independent (AI) growth of prostate cancer (CaP) is strongly correlated with ?-amidated neuropeptide hormone production. We contend that PAM/PHM is an excellent therapeutic target as it is the only known enzyme associated with peptide amidation. Our research platform seeks support to develop the experimental tools to map the TS geometry through a combination of KIEs with steady and transient state kinetics. With quantum computational approaches, chemically stable analogues will be selected matching the molecular electrostatic potential (MEP) maps to databases of known compounds. Establishing a roadmap towards therapeutic discovery by combining the approach of mechanistic enzymology and computer aided drug design will be valuable to those studying the numerous PAM-dependent cancers. In addition, our research team will use peptidomic profiling of AI CaP cell lines to isolate and characterize novel ?-amidated peptide hormones to serve as biomarkers for early detection and improve therapeutic efficacy (vide supra). Subsequent in vitro feeding studies will identify which amidated peptide hormone(s) mediate tumor proliferation. The far reaching goal of identifying potent biomarkers associated with tumor proliferation will be the design of a robust assay for the early diagnosis and prevention of malignant disease.
This proposal has selected androgen independent prostate cancer (AI CaP) as a feasibility study to develop a platform technology directed towards the rational therapeutic targeting and early detection protocols of all cancers that utilize PAM for progression. The progression of androgen independent (AI) prostate cancer(CaP) is directly correlated with ?-amidated neuropeptide hormone production by peptidylglycine alpha-amidating monooxygenase (PAM) in differentiated neuroendocrine cells of the prostate. Our hypothesis states that the progression of androgen independent (AI) prostate cancer (CaP) is directly correlated with ?-amidated neuropeptide hormone production by peptidylglycine alpha-amidating monooxygenase (PAM) in the differentiated neuroendocrine cells of the prostate. This places PAM catalysis central to therapeutic design and its ?-amidated peptide growth hormone products as biomarkers for transformation into and progression of AI CaP. This proposal will identify: 1) clear and specific catalytic regimes for therapeutic targeting of PAM and 2) novel amidated peptide hormones responsible for tumor proliferation leading to dramatically improved early detection capabilities.
| McIntyre, Neil R; Lowe Jr, Edward W; Battistini, Matthew R et al. (2016) Inactivation of peptidylglycine ?-hydroxylating monooxygenase by cinnamic acid analogs. J Enzyme Inhib Med Chem 31:551-62 |
| Washington, Courtney; Maxwell, Jamere; Stevenson, Joenathan et al. (2015) Mechanistic studies of the tyrosinase-catalyzed oxidative cyclocondensation of 2-aminophenol to 2-aminophenoxazin-3-one. Arch Biochem Biophys 577-578:24-34 |
