Abstract
Objective of the study
Protein N‐myristoylation enables localization to membranes and helps maintain protein conformation and function. N‐myristoyltransferases (NMT) catalyze co‐ or post‐translational myristoylation of Src family kinases and other oncogenic proteins, thereby regulating their function. The goal of this study is 1) to demonstrate that N‐myristoylation is essential for the tumorigenic potential of oncogenioc proteins such as Src kinase; 2) to identify novel lead compounds to inhibit the NMT enzymatic functions; 3) to demonstrate that the compound exhibits its inhibitory function on cancer progression.
Statement of Methods
NMT1/2 proteins were purified for the evaluation of their enzymatic functions. The proteins were further crystalized for study their structure. The myristoylation of Src kinase was detected by Click chemistry. Protein fractionation was evaluated by immunoblotting. A low throughput screening was performed to identify an myristoyl‐CoA analog to inhibit NMT enzymatic function. TCGA database was used for the analysis of the expression correlation. Additionally, inhibition of cell proliferation, migration, invasion assays and cell cycle analysis were analyzed in numerous cancer cells. Prostate regeneration assay and xenograft tumor models were applied for in vivo studies.
Summary of the results
We provide genetic and pharmacological evidence that inhibiting the N‐myristoyltransferase NMT1 suppresses cell cycle progression, proliferation and malignant growth of prostate cancer cells. Loss of myristoylation abolished the tumorigenic potential of Src and its synergy with androgen receptor in mediating tumor invasion. We identified the myristoyl‐CoA analog B13 as a small molecule inhibitor of NMT1 enzymatic activity. B13 exposure blocked Src myristoylation and Src localizaiton to the cytoplasmic membrane, attenuating Srcmediated oncogenic signaling. B13 exerted its antiinvasive and antitumor effects against prostate cancer cells with minimal toxic side‐effects in vivo. Structural optimization based on structure‐activity relationships enabled the chemical synthesis of LCL204 with enhanced inhibitory potency against NMT1.
Conclusion
Our study demonstrates that B13, a myristoyl‐CoA analog, inhibits NMT enzymatic functions and Src mediated tumorigenesis. Our results offer a preclincal proof of concept for the use of protein myristoylation inhibitors as a strategy to block prostate cancer progression.
Support or Funding Information
NIH (R01CA172495) and DOD (W81XWH‐15‐1‐0507)
This is from the Experimental Biology 2018 Meeting. There is no full text article associated with this published in The FASEB Journal.