Chemical dissection of the link between streptozotocin, O-GlcNAc, and pancreatic cell death

TY - JOUR

T1 - Chemical dissection of the link between streptozotocin, O-GlcNAc, and pancreatic cell death

AU - Pathak, Shalini

AU - Dorfmueller, Helge C.

AU - Borodkin, Vladimir S.

AU - van Aalten, Daan M. F.

PY - 2008/8/25

Y1 - 2008/8/25

N2 - Streptozotocin is a natural product that selectively kills insulin-secreting beta cells, and is widely used to generate mouse models of diabetes or treat pancreatic tumors. Several studies suggest that streptozotocin toxicity stems from its N-nitrosourea moiety releasing nitric oxide and possessing DNA alkylating activity. However, it has also been proposed that streptozotocin induces apoptosis by inhibiting O-GlcNAcase, an enzyme that, together with O-GlcNAc transferase, is important for dynamic intracellular protein O-glycosylation. We have used galacto-streptozotocin to chemically dissect the link between O-GlcNAcase inhibition and apoptosis. Using X-ray crystallography, enzymology, and cell biological studies on an insulinoma cell line, we show that, whereas streptozotocin competitively inhibits O-GlcNAcase and induces apoptosis, its galacto-configured derivative no longer inhibits O-GlcNAcase, yet still induces apoptosis. This supports a general chemical poison mode of action for streptozotocin, suggesting the need for using more specific inhibitors to study protein O-GlcNAcylation.

AB - Streptozotocin is a natural product that selectively kills insulin-secreting beta cells, and is widely used to generate mouse models of diabetes or treat pancreatic tumors. Several studies suggest that streptozotocin toxicity stems from its N-nitrosourea moiety releasing nitric oxide and possessing DNA alkylating activity. However, it has also been proposed that streptozotocin induces apoptosis by inhibiting O-GlcNAcase, an enzyme that, together with O-GlcNAc transferase, is important for dynamic intracellular protein O-glycosylation. We have used galacto-streptozotocin to chemically dissect the link between O-GlcNAcase inhibition and apoptosis. Using X-ray crystallography, enzymology, and cell biological studies on an insulinoma cell line, we show that, whereas streptozotocin competitively inhibits O-GlcNAcase and induces apoptosis, its galacto-configured derivative no longer inhibits O-GlcNAcase, yet still induces apoptosis. This supports a general chemical poison mode of action for streptozotocin, suggesting the need for using more specific inhibitors to study protein O-GlcNAcylation.

KW - beta-D-glucosaminidase

KW - N-acetylglucosamine

KW - Cytoplasmic proteins

KW - Structural insights

KW - Nitric oxide

KW - Inhibitor

KW - Glycosylation

KW - Transferase

KW - Alloxan

KW - Nuclear

U2 - 10.1016/j.chembiol.2008.06.010

DO - 10.1016/j.chembiol.2008.06.010

M3 - Article

C2 - 18721751

SN - 1074-5521

VL - 15

SP - 799

EP - 807

JO - Chemistry & Biology

JF - Chemistry & Biology

IS - 8

ER -