Cleavage of focal adhesion kinase is an early marker and modulator of oxidative stress-induced apoptosis.
Focal adhesion kinase (FAK) is a signaling molecule associated with cell survival. Previously, we showed that thimerosal, a reactive oxygen species (ROS) generator, can acutely induce FAK tyrosine phosphorylation (within minutes) and chronically induce apoptosis (within days) by redox modulation in HeLa S cells. In the present study, we report that a prolonged oxidative stress by thimerosal induces a remarkable cleavage of FAK, which is accompanied with apoptosis. In fact, the kinetics of FAK cleavage has a good correlation with and actually preceding the apoptosis that was independent of anoikis. The effects were almost completely blocked by the pretreatment with either N-acetyl-l-cysteine (ROS scavenger) or Z-VAD-FMK (pan-caspase inhibitor), suggesting ROS-induced caspase activation as a key mechanism. They could be also reproduced by hydrogen peroxide alone, which appeared to be responsible for thimerosal-mediated oxidative stress-induced apoptosis. Additionally, the down regulation of FAK with antisense oligonucleotide dramatically augmented thimerosal-induced apoptosis. We could observe similar results using human corneal epithelial cells. Taken together, our results show that FAK is a critical cellular target of caspases during oxidative stress (particularly by hydrogen peroxide), resulting in the acceleration of subsequent apoptosis regardless of the anchorage status of cells. From the present results, it is more likely that not cell detachment but the proteolytic cleavage (or inhibition) of FAK is a key modulator as well as a promising indicator of apoptosis in epithelial cells under oxidative stress.
Mian
Md Firoz
MF
Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang 790-784, South Korea.
Kang
Changkeun
C
Lee
Seunghwan
S
Choi
Jang Hyun
JH
Bae
Sun Sik
SS
Kim
Sun-Hee
SH
Kim
Yun-Hee
YH
Ryu
Sung Ho
SH
Suh
Pann-Ghill
PG
Kim
Jong-Shu
JS
Kim
Euikyung
E
D000111:Acetylcysteine / Q000494:pharmacology; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D016227:Benzoquinones / Q000494:pharmacology; D053148:Caspase 3 / Q000378:metabolism; D061945:Caspase Inhibitors; D002461:Cell Line, Transformed; D002614:Chelating Agents / Q000494:pharmacology; D003315:Cornea / Q000166:cytology; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051417:Focal Adhesion Kinase 1 / Q000235:genetics / Q000378:metabolism*; D051418:Focal Adhesion Kinase 2 / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D047029:Lactams, Macrocyclic / Q000494:pharmacology; D018384:Oxidative Stress / Q000502:physiology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D017828:Rifabutin / Q000031:analogs & derivatives; D012459:Salicylates / Q000494:pharmacology; D013438:Sulfhydryl Compounds / Q000494:pharmacology; D013849:Thimerosal / Q000494:pharmacology
D000590:Amino Acid Chloromethyl Ketones; D016227:Benzoquinones; D061945:Caspase Inhibitors; D002614:Chelating Agents; D015853:Cysteine Proteinase Inhibitors; D047029:Lactams, Macrocyclic; D047428:Protein Kinase Inhibitors; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D012459:Salicylates; D013438:Sulfhydryl Compounds; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D017828:Rifabutin; D013849:Thimerosal; D004533:Egtazic Acid; C020754:herbimycin; D006861:Hydrogen Peroxide; C441201:thiosalicylic acid; D051417:Focal Adhesion Kinase 1; D051418:Focal Adhesion Kinase 2; C496050:PTK2 protein, human; D053148:Caspase 3; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D000111:Acetylcysteine