Enzyme-Based Platform Technology for Cancers Utilizing PAM: Etiology of Novel Ami

Xavier University Of Louisiana, New Orleans LA

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Abstract

? DESCRIPTION (provided by applicant): 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.