Fhit modulation of the Akt-survivin pathway in lung cancer cells: Fhit-tyrosine 114 (Y114) is essential.
The Fhit tumor suppressor binds and hydrolyses diadenosine polyphosphates and the Fhit-substrate complex has been proposed as a proapoptotic effector, as determined by infection of susceptible cancer cells with adenoviruses carrying wild-type fragile histidine triad (FHIT) or catalytic site mutants. The highly conserved Fhit tyrosine 114 (Y114), within the unstructured loop C-terminal of the catalytic site, can be phosphorylated by Src family tyrosine kinases, although endogenous phospho-Fhit is rarely detected. To explore the importance of Y114 and identify Fhit-mediated signaling events, wild-type and Y114 mutant FHIT-expressing adenoviruses were introduced into two human lung cancer cell lines. Caspase-dependent apoptosis was effectively induced only by wild-type but not Y114 mutant Fhit proteins. By expression profiling of FHIT versus mutant FHIT-infected cells, we found that survivin, an Inhibitor of Apoptosis Protein (IAP) family member, was significantly decreased by wild-type Fhit. In addition, Fhit inhibited activity of Akt, a key effector in the phosphatidylinositol 3-OH kinase (PI3K) pathway; loss of endogenous Fhit expression caused increased Akt activity in vitro and in vivo, and overexpression of constitutively active Akt inhibited Fhit-induced apoptosis. The results indicate that the Fhit Y114 residue plays a critical role in Fhit-induced apoptosis, occurring through inactivation of the PI3K-Akt-survivin signal pathway.
Semba
S
S
Comprehensive Cancer Center and Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, 43210, USA.
Trapasso
F
F
Fabbri
M
M
McCorkell
K A
KA
Volinia
S
S
Druck
T
T
Iliopoulos
D
D
Pekarsky
Y
Y
Ishii
H
H
Garrison
P N
PN
Barnes
L D
LD
Croce
C M
CM
Huebner
K
K
D017766:Acid Anhydride Hydrolases / Q000235:genetics*; D000256:Adenoviridae / Q000235:genetics; D015153:Blotting, Western; D058534:Class I Phosphatidylinositol 3-Kinases; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000502:physiology*; D016147:Genes, Tumor Suppressor / Q000502:physiology*; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D000077022:Survivin; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000235:genetics / Q000378:metabolism*; D000099170:Bis(5'-adenosyl)triphosphatase
D017766:Acid Anhydride Hydrolases; D058534:Class I Phosphatidylinositol 3-Kinases; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D034741:RNA, Small Interfering; D000077022:Survivin; D014443:Tyrosine; D000099170:Bis(5'-adenosyl)triphosphatase; C107489:BIRC5 protein, human; C484760:PIK3CA protein, human