A glycosylated antitumor ether lipid kills cells via paraptosis-like cell death

作者：Samadder Pranati; Bittman Robert; Byun Hoe Sup; Arthur Gilbert^*

来源：Biochemistry and Cell Biology, 2009, 87(2): 401-414.

DOI：10.1139/O08-147

• glycosylated antitumor ether lipid
• cell death
• apoptosis
• autophagy
• paraptosis

Glycosylated antitumor ether lipids (GAELs) have superior anticancer properties relative to the alkyllysophospholipid class, but there have been no studies of the mechanisms of these compounds. The prototype GAEL, 1-O-hexadecyl-2-O-methyl-3-O-(2'-amino-2'-deoxy-beta-D-glucopyranosyl)-sn-glycerol (Gln), effectively killed mouse embryonic fibroblasts (MEFs) lacking key molecules involved in caspase-dependent apoptosis, and cell death was not prevented by caspase inhibitors. Gln did not cause a loss of mitochondrial membrane potential, even in rounded-up dying cells. Gln stimulated the appearance and accumulation of LC3-II, a protein marker for autophagy, in a variety of cells, including wild-type MEFs, but not in MEFs lacking ATG5, a key protein required for autophagy. Gln induced LC3 puncta formation in Chinese hamster ovary cells stably expressing a LC3-green fluorescent protein fusion protein. Thus, Gln appears to induce autophagy. Autophagy was mTOR-independent and was not inhibited by 3-methyladenine or wortmannin. Although Gln is toxic, cellular ability to undergo autophagy was not essential for its toxicity. Furthermore, the GAEL analog 2-deoxy-C-Glc induced LC3 puncta formation but did not kill the cells. Gln, but not 2-deoxy-C-Glc, caused the accumulation of cytoplasmic acidic vacuoles in the cells. Our data suggest that GAELs may activate autophagy; however, GAELs do not kill cells by apoptosis or autophagy but rather by a paraptosis-like cell death mechanism.

• 出版日期2009-4