Inhibition of the G₂ DNA Damage Checkpoint and of Protein Kinases Chk1 and Chk2 by the Marine Sponge Alkaloid Debromohymenialdisine

TY - JOUR

T1 - Inhibition of the G2 DNA Damage Checkpoint and of Protein Kinases Chk1 and Chk2 by the Marine Sponge Alkaloid Debromohymenialdisine

AU - Curman, Darko

AU - Cinel, Bruno

AU - Williams, David E.

AU - Rundle, Natalie

AU - Block, Wesley D.

AU - Goodarzi, Aaron A.

AU - Hutchins, James R.

AU - Clarke, Paul R.

AU - Zhou, Bin Bing

AU - Lees-Miller, Susan P.

AU - Andersen, Raymond J.

AU - Roberge, Michel

PY - 2001/1/25

Y1 - 2001/1/25

N2 - Cells can respond to DNA damage by activating checkpoints that delay cell cycle progression and allow time for DNA repair. Chemical inhibitors of the G2 phase DNA damage checkpoint may be used as tools to understand better how the checkpoint is regulated and may be used to sensitize cancer cells to DNA-damaging therapies. However, few inhibitors are known. We used a cell-based assay to screen natural extracts for G2 checkpoint inhibitors and identified debromohymenialdisine (DBH) from a marine sponge. DBH is distinct structurally from previously known G2 checkpoint inhibitors. It inhibited the G2 checkpoint with an IC50 of 8 μM and showed moderate cytotoxicity (IC50 = 25 μM) toward MCF-7 cells. DBH inhibited the checkpoint kinases Chk1 (IC50 = 3 μM) and Chk2 (IC50 = 3.5 μM) but not ataxiatelangiectasia mutated (ATM), ATM-Rad3-related protein, or DNA-dependent protein kinase in vitro, indicating that it blocks two major branches of the checkpoint pathway downstream of ATM. It did not cause the activation or inhibition of different signal transduction proteins, as determined by mobility shift analysis in Western blots, suggesting that it inhibits a narrow range of protein kinases in vivo.

AB - Cells can respond to DNA damage by activating checkpoints that delay cell cycle progression and allow time for DNA repair. Chemical inhibitors of the G2 phase DNA damage checkpoint may be used as tools to understand better how the checkpoint is regulated and may be used to sensitize cancer cells to DNA-damaging therapies. However, few inhibitors are known. We used a cell-based assay to screen natural extracts for G2 checkpoint inhibitors and identified debromohymenialdisine (DBH) from a marine sponge. DBH is distinct structurally from previously known G2 checkpoint inhibitors. It inhibited the G2 checkpoint with an IC50 of 8 μM and showed moderate cytotoxicity (IC50 = 25 μM) toward MCF-7 cells. DBH inhibited the checkpoint kinases Chk1 (IC50 = 3 μM) and Chk2 (IC50 = 3.5 μM) but not ataxiatelangiectasia mutated (ATM), ATM-Rad3-related protein, or DNA-dependent protein kinase in vitro, indicating that it blocks two major branches of the checkpoint pathway downstream of ATM. It did not cause the activation or inhibition of different signal transduction proteins, as determined by mobility shift analysis in Western blots, suggesting that it inhibits a narrow range of protein kinases in vivo.

UR - https://www.scopus.com/pages/publications/0242659422

U2 - 10.1074/jbc.M100728200

DO - 10.1074/jbc.M100728200

M3 - Article

C2 - 11279124

AN - SCOPUS:0242659422

SN - 0021-9258

VL - 276

SP - 17914

EP - 17919

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

IS - 21

ER -