Hu1D10 induces apoptosis concurrent with activation of the AKT survival pathway in human chronic lymphocytic leukemia cells.
The 1D10 antigen is the target for Hu1D10 (apolizumab), a humanized HLA-DR beta-chain-specific antibody that is currently in clinical trials for hematologic malignancies. We demonstrate that Hu1D10 induces caspase-independent apoptosis following secondary cross-linking in primary chronic lymphocytic leukemia (CLL) cells. Generation of reactive oxygen species (ROS) and signal transduction, as evidenced by phosphorylation of Syk and AKT, were noted. The source of the Hu1D10-induced ROS was examined using the Raji lymphoblastic cell line with engineered defects in the mitochondrial respiratory chain. Hu1D10 treatment of clones with deficient mitochondrial respiration produced ROS suggesting a cytoplasmic source. Administration of ROS scavengers to primary CLL cells prior to Hu1D10 treatment diminished AKT activation. Treatment with Hu1D10 and the phosphatidylinositol 3-kinase inhibitor LY294002 demonstrated in vitro synergy with enhanced apoptosis. In conjunction with an ongoing clinical trial, blood samples were collected following intravenous infusion of Hu1D10 and analyzed for phosphorylation of AKT. Two of 3 patient samples showed a sustained increase in AKT phosphorylation following Hu1D10 administration. These data suggest that Hu1D10 ligation in CLL cells induces death and survival signals for which combination therapies may be designed to greatly enhance efficiency of both Hu1D10 and other class II antibodies in development.
Mone
Andrew P
AP
Division of Hematology-Oncology, The Ohio State University, Columbus 43210, USA.
Huang
Peng
P
Pelicano
Helene
H
Cheney
Carolyn M
CM
Green
Jennifer M
JM
Tso
J Yun
JY
Johnson
Amy J
AJ
Jefferson
Sara
S
Lin
Thomas S
TS
Byrd
John C
JC
D000111:Acetylcysteine / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis; D015153:Blotting, Western; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival; D002867:Chromones / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism; D004579:Electron Transport; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000378:metabolism*; D021962:Membrane Microdomains; D008928:Mitochondria / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D017382:Reactive Oxygen Species; D015398:Signal Transduction; D013997:Time Factors
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D002867:Chromones; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D009025:Morpholines; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017382:Reactive Oxygen Species; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C448699:apolizumab; D000111:Acetylcysteine