OSU-03012, a novel celecoxib derivative, is cytotoxic to myeloma cells and acts through multiple mechanisms.
OBJECTIVE
OSU-03012 is a novel celecoxib derivative, without cyclooxygenase-2 inhibitory activity, capable of inducing apoptosis in various cancer cells types, and is being developed as an anticancer drug. We investigated the in vitro activity of OSU-03012 in multiple myeloma (MM) cells.


METHODS
U266, ARH-77, IM-9, and RPMI-8226, and primary myeloma cells were exposed to OSU-03012 for 6, 24, or 72 h. Cytotoxicity, caspase activation, apoptosis, and effects on intracellular signaling pathways were assessed.


RESULTS
OSU-03012 was cytotoxic to MM cells with mean LC50 3.69 +/- 0.23 and 6.25 +/- 0.86 micromol/L and at 24 h for primary MM cells and cell lines, respectively. As a known PDK-1 inhibitor, OSU-03012 inhibited the PI3K/Akt pathway with downstream effects on BAD, GSK-3beta, FoxO1a, p70S6K, and MDM-2. However, transfection of MM cells with constitutively active Akt failed to protect against cell death, indicating activity against other pathways is important. Phospho (p)-signal transducers and activators of transcription 3 and p-MAP/ERK kinase 1/2 were down-regulated, suggesting that OSU-03012 also inhibited the Janus-activated kinase 2/signal transducer and activator of transcription 3 and mitogen-activated protein kinase pathways. Although expression of Bcl-2 proteins was unchanged, OSU-03012 also down-regulated survivin and X-linked inhibitor of apoptosis (XIAP), and also induced G2 cell cycle arrest with associated reductions in cyclins A and B. Finally, although OSU-03012 induced cleavage of caspases 3, 8 and 9, caspase inhibition did not prevent cell death.


CONCLUSIONS
We conclude that OSU-03012 has potent activity against MM cells and acts via different mechanisms in addition to phosphoinositide-3-kinase/Akt pathway inhibition. These studies provide rationale for the clinical investigation of OSU-03012 in MM.
Zhang
Shuhong
S
Division of Hematology and Oncology, Department of Internal Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
Suvannasankha
Attaya
A
Crean
Colin D
CD
White
Valerie L
VL
Johnson
Amy
A
Chen
Ching-Shih
CS
Farag
Sherif S
SS
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D020169:Caspases / Q000502:physiology; D002403:Cathepsins / Q000502:physiology; D045744:Cell Line, Tumor; D016213:Cyclins / Q000235:genetics; D016195:G2 Phase / Q000187:drug effects; D006801:Humans; D009101:Multiple Myeloma / Q000188:drug therapy*; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology; D011720:Pyrazoles / Q000494:pharmacology*; D050796:STAT3 Transcription Factor / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology*
D000970:Antineoplastic Agents; D016213:Cyclins; C500894:OSU 03012; D011720:Pyrazoles; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D013449:Sulfonamides; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D002403:Cathepsins; D020169:Caspases