From the Gla domain to a novel small-molecule detector of apoptosis.
Apoptosis plays a pivotal role in the etiology or pathogenesis of numerous medical disorders, and thus, targeting of apoptotic cells may substantially advance patient care. In our quest for novel low-molecular-weight probes for apoptosis, we focused on the uncommon amino acid gamma-carboxyglutamic acid (Gla), which plays a vital role in the binding of clotting factors to negatively charged phospholipid surfaces. Based on the alkyl-malonic acid motif of Gla, we have developed and now present ML-10 (2-(5-fluoro-pentyl)-2-methyl-malonic acid, MW=206 Da), the prototypical member of a novel family of small-molecule detectors of apoptosis. ML-10 was found to perform selective uptake and accumulation in apoptotic cells, while being excluded from either viable or necrotic cells. ML-10 uptake correlates with the apoptotic hallmarks of caspase activation, Annexin-V binding and disruption of mitochondrial membrane potential. The malonate moiety was found to be crucial for ML-10 function in apoptosis detection. ML-10 responds to a unique complex of features of the cell in early apoptosis, comprising irreversible loss of membrane potential, permanent acidification of cell membrane and cytoplasm, and preservation of membrane integrity. ML-10 is therefore the most compact apoptosis probe known to date. Due to its fluorine atom, ML-10 is amenable to radio-labeling with the (18)F isotope, towards its potential future use for clinical positron emission tomography imaging of apoptosis.
Cohen
Avi
A
Aposense Ltd, 5-7 Ha'Odem St, Kiryat Matalon, PO Box 7119, Petach Tikva, Israel. avi@aposense.com
Shirvan
Anat
A
Levin
Galit
G
Grimberg
Hagit
H
Reshef
Ayelet
A
Ziv
Ilan
I
D015055:1-Carboxyglutamic Acid / Q000737:chemistry*; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis; D002460:Cell Line; D015195:Drug Design; D005456:Fluorescent Dyes / Q000032:analysis / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019169:Jurkat Cells; D008564:Membrane Potentials; D008764:Methylmalonic Acid / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D049268:Positron-Emission Tomography; D013997:Time Factors
C532430:5-fluoropentyl-2-methylmalonic acid; D017304:Annexin A5; D005456:Fluorescent Dyes; D015055:1-Carboxyglutamic Acid; D008764:Methylmalonic Acid