6ovg
L-Methionine Depletion with an Engineered Human Enzyme Disrupts Prostate Cancer Metabolism
Structural highlights
DiseaseCGL_HUMAN Defects in CTH are the cause of cystathioninuria (CSTNU) [MIM:219500. It is an autosomal recessive phenotype characterized by abnormal accumulation of plasma cystathionine, leading to increased urinary excretion.[1] [2] FunctionCGL_HUMAN Catalyzes the last step in the trans-sulfuration pathway from methionine to cysteine. Has broad substrate specificity. Converts cystathionine to cysteine, ammonia and 2-oxobutanoate. Converts two cysteine molecules to lanthionine and hydrogen sulfide. Can also accept homocysteine as substrate. Specificity depends on the levels of the endogenous substrates. Generates the endogenous signaling molecule hydrogen sulfide (H2S), and so contributes to the regulation of blood pressure. Acts as a cysteine-protein sulfhydrase by mediating sulfhydration of target proteins: sulfhydration consists of converting -SH groups into -SSH on specific cysteine residues of target proteins such as GAPDH, PTPN1 and NF-kappa-B subunit RELA, thereby regulating their function.[3] [4] [5] Publication Abstract from PubMedExtensive studies in prostate cancer and other malignancies have revealed that l-methionine (l-Met) and its metabolites play a critical role in tumorigenesis. Preclinical and clinical studies have demonstrated that systemic restriction of serum l-Met, either via partial dietary restriction or with bacterial l-Met-degrading enzymes exerts potent antitumor effects. However, administration of bacterial l-Met-degrading enzymes has not proven practical for human therapy because of problems with immunogenicity. As the human genome does not encode l-Met-degrading enzymes, we engineered the human cystathionine-gamma-lyase (hMGL-4.0) to catalyze the selective degradation of l-Met. At therapeutically relevant dosing, hMGL-4.0 reduces serum l-Met levels to >75% for >72 h and significantly inhibits the growth of multiple prostate cancer allografts/xenografts without weight loss or toxicity. We demonstrate that in vitro, hMGL-4.0 causes tumor cell death, associated with increased reactive oxygen species, S-adenosyl-methionine depletion, global hypomethylation, induction of autophagy, and robust poly(ADP-ribose) polymerase (PARP) cleavage indicative of DNA damage and apoptosis. Enzyme-mediated depletion of serum l-Met abrogates prostate cancer growth via multiple mechanisms without evidence of systemic toxicity.,Lu WC, Saha A, Yan W, Garrison K, Lamb C, Pandey R, Irani S, Lodi A, Lu X, Tiziani S, Zhang YJ, Georgiou G, DiGiovanni J, Stone E Proc Natl Acad Sci U S A. 2020 May 20. pii: 1917362117. doi:, 10.1073/pnas.1917362117. PMID:32434918[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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