Inhibition of Akt potentiates 2-DG-induced apoptosis via downregulation of UPR in acute lymphoblastic leukemia.
The ability to pair the regulation of metabolism and cellular energetics with oncogenes and tumor suppressor genes provides cancer cells with a growth and survival advantage over normal cells. We investigated the mechanism of cell death induced by 2-deoxy-D-glucose (2-DG), a sugar analog with dual activity of inhibiting glycolysis and N-linked glycosylation, in acute lymphoblastic leukemia (ALL). We found that, unlike most other cancer phenotypes in which 2-DG only inhibits cell proliferation under normoxic conditions, ALL lymphoblasts undergo apoptosis. Bp-ALL cell lines and primary cells exhibited sensitivity to 2-DG, whereas T-ALL cells were relatively resistant, revealing phenotypic differences within ALL subtypes. Cotreatment with D-mannose, a sugar essential for N-linked glycosylation, rescues 2-DG-treated ALL cells, indicating that inhibition of N-linked glycosylation and induction of ER stress and the unfolded protein response (UPR) is the predominant mechanism of 2-DG's cytotoxicity in ALL. 2-DG-treated ALL cells exhibit upregulation of P-AMPK, P-Akt, and induction of ER stress/UPR markers (IRE1α, GRP78, P-eIF2α, and CHOP), which correlate with PARP cleavage and apoptosis. In addition, we find that pharmacologic and genetic Akt inhibition upregulates P-AMPK, downregulates UPR, and sensitizes ALL cells to remarkably low doses of 2-DG (0.5 mmol/L), inducing 85% cell death and overcoming the relative resistance of T-ALL. In contrast, AMPK knockdown rescues ALL cells by upregulating the prosurvival UPR signaling. Therefore, 2-DG induces ALL cell death under normoxia by inducing ER stress, and AKT and AMPK, traditionally thought to operate predominantly on the glycolytic pathway, differentially regulate UPR activity to determine cell death or survival.
Department of Pediatric Hematology-Oncology, University of Miami Miller School of Medicine, Miami, FL 33101, USA.
Joanna
J
DeSalvo
Jeffim N
JN
Kuznetsov
Jianfeng
J
Du
Gilles M
GM
Leclerc
Guy J
GJ
Leclerc
Theodore J
TJ
Lampidis
Julio C
JC
Barredo
D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D003847:Deoxyglucose / Q000494:pharmacology; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects; D006031:Glycosylation; D006801:Humans; D015448:Leukemia, B-Cell / Q000378:metabolism / Q000473:pathology; D015458:Leukemia, T-Cell / Q000378:metabolism / Q000473:pathology; D008358:Mannose / Q000494:pharmacology; D051058:Oncogene Protein v-akt / Q000378:metabolism*; D015398:Signal Transduction; D056811:Unfolded Protein Response
D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D003847:Deoxyglucose; D051058:Oncogene Protein v-akt; D055372:AMP-Activated Protein Kinases; D008358:Mannose