RT Journal Article
SR Electronic
T1 Mis-Trafficking of Endosomal Urokinase Proteins Triggers Drug-Induced Glioma Nonapoptotic Cell Death
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 683
OP 696
DO 10.1124/mol.114.096602
VO 87
IS 4
A1 Nagarekha Pasupuleti
A1 Ana Cristina Grodzki
A1 Fredric Gorin
YR 2015
UL http://molpharm.aspetjournals.org/content/87/4/683.abstract
AB 5-Benzylglycinyl-amiloride (UCD38B) is the parent molecule of a class of anticancer small molecules that kill proliferative and nonproliferative high-grade glioma cells by programmed necrosis. UCD38B intracellularly triggers endocytosis, causing 40–50% of endosomes containing proteins of the urokinase plasminogen activator system (uPAS) to relocate to perinuclear mitochondrial regions. Endosomal “mis-trafficking” caused by UCD38B in human glioma cells corresponds to mitochondrial depolarization with the release and nuclear translocation of apoptotis-inducing factor (AIF) followed by irreversible caspase-independent cell demise. High-content quantification of immunocytochemical colocalization studies identified that UCD38B treatment increased endocytosis of the urokinase plasminogen activator (uPA), its receptor (uPAR), and plasminogen activator inhibitor-1 (PAI-1) into the early and late endosomes by 4- to 5-fold prior to AIF nuclear translocation and subsequent glioma demise. PAI-1 was found to comparably relocate with a subset of early and late endosomes in four different human glioma cell lines after UCD38B treatment, followed by caspase-independent, nonapoptotic cell death. Following UCD38B treatment, the receptor guidance protein LRP-1, which is required for endosomal recycling of the uPA receptor to the plasmalemma, remained abnormally associated with PAI-1 in early and late endosomes. The resultant aberrant endosomal recycling increased the total cellular content of the uPA–PAI-1 protein complex. Reversible inhibition of cellular endocytosis demonstrated that UCD38B bypasses the plasmalemmal uPAS complex and directly acts intracellularly to alter uPAS endocytotic trafficking. UCD38B represents a class of small molecules whose anticancer cytotoxicity is a consequence of causing the mis-trafficking of early and late endosomes containing uPAS cargo and leading to AIF-mediated necrotic cell death.