Actinonin

Actinonin ((-)-Actinonin) is a naturally occurring antibacterial agent produced by Actinomyces. Actinonin inhibits aminopeptidase M, aminopeptidase N and leucine aminopeptidase. Actinonin is a potent reversible peptide deformylase (PDF) inhibitor with a K_i of 0.28 nM. Actinonin also inhibits MMP-1, MMP-3, MMP-8, MMP-9, and hmeprin α with K_i values of 300 nM, 1,700 nM, 190 nM, 330 nM, and 20 nM, respectively. Actinonin is an apoptosis inducer. Actinonin has antiproliferative and antitumor activities^{[1][2][3][4][5]}. IC50 & Target:Ki: 0.28 nM (Peptide deformylase (PDF))^[2], 300 nM (MMP-1), 1,700 nM (MMP-3), 190 nM (MMP-8), 330 nM (MMP-9)^[3], and 20 nM (hmeprin α)^[5]
Apoptosis^[1]
Aminopeptidase M, Aminopeptidase N and Leucine aminopeptidase^[1] In Vitro: Actinonin inhibits cell growth in various human tumor cell lines. The IC₅₀ of 4, 6.9, 12.8, 16.6, 27.4, 15.7 and 49.3 μM for Raji cells, MDA-MB-468 cells,PC3 cells, SK-LC-19 cells, Hela cells, HT-1080 cells and AL67 cells, respectively^[1].
HsPDF is a critical target of actinonin and that the inhibition of this protein in the mitochondria leads to cell death in tumor cells. Actinonin treatment of cells led to a tumor-specific mitochondrial membrane depolarization and ATP depletion in a time- and dose-dependent manner^[1].
Actinonin is a potent inhibitor of all three forms (Zn-, Ni-, and Fe-) of peptide deformylases from both S. aureus and E. coli bacteria. Under the assay conditions, the IC₅₀ values for Actinonin are 90, 3, 0.8, and 11 nM for Zn-PDF (E. coli), Ni-PDF (E. coli), Fe-PDF (E. coli), and Ni-PDF (S. aureus), respectively^[2].
Actinonin is active against Gram-positive bacteria, including S. aureus (MIC value of 8-16 μg/mL), Streptococcus pyogenes (MIC value of 8 μg/mL) and Streptococcus epidermidis (MIC value of 2-4 μg/mL). Actinonin is also active against fastidious Gramne-gative bacteria, such as H. influenzae (MIC value of 1-2 μg/mL), Moraxella catarrhalis (MIC value of 0.5 μg/mL), and Neisseria gonorrheae (MIC value of 1-4 μg/mL). Actinonin is very active against the H. influenzae acr (MIC value of 0.13 μg/mL) and E. coli acr (MIC value of 0.25 μg/mL) efflux pump mutants^[2]. In Vivo: Actinonin has been safely administered to mice as an antibiotic at doses up to 400 mg/kg. Actinonin does not appear to have significant toxicity to normal tissues, despite its antitumor activity in vitro. Remarkably, Actinonin exhibits significant antitumor activity when given i.p. or orally in a CWR22 human prostate tumor xenograft model in nude mice. During treatment, the animals show no signs of toxicity^[1].