Methionine Aminopeptidase Inhibitors in Mammalian Cells

Abstract

Mycobacterium tuberculosis (Mtb) is the leading cause of mortality from an infectious disease, worldwide. Mtb benefits from an HIV‐weakened immune system, and leads to a statistically increased risk of HIV/TB co‐infection. The rise of multi‐drug resistant Mtb strains makes treatment difficult, thus a novel drug may be required to eliminate Mtb infection. Our collaborators at Texas Southern University have identified novel bacterial methionine aminopeptidase (MtMetAP1) inhibitors. Genetic knockout studies support the lethality of the deletion of MtMetAP1 in Mtb. Further studies support the existence of an ortholog of MtMetAP1 in Homo sapiens (HsMetAP1). In addition, humans have several paralogs of MetAP, which perform similar essential functions to MetAP1. Although these novel inhibitors are effective against Mtb, the cytotoxicity in mammalian cells has not been established. To address this, we tested a MtMetAP1 inhibitor (UST‐001) on H1299 human lung carcinoma cells and Mlg‐2908 mouse lung fibroblast cells. Using flow cytometry and a WST‐1 assay to assess cell viability, we determined the LC50 to be 1.652μM in the H1299 lung carcinoma cell line. The consistent non‐significance of our data supports our hypothesis regarding the non‐fatal nature of this drug in a human cell line, as there were no significant differences between controls and experimental conditions. Initial results from WST‐1 assays with Mlg‐2908 cells indicate that the LC50 for Mlg‐2908 is between 5 and 10μM, higher than that of H1299. Further studies using flow cytometry analysis are required to solidify this comparison, while another apoptotic assay may also be beneficial to determine an exact LC50 and ultimately the efficacy of this drug.Support or Funding InformationU.S. DOE, Hispanic‐Serving Institutions, STEM Articulation Grant P031C110128, the Cullen‐Smith Foundation, and the UST Committee for Student Research for their financial support