The antiapoptotic effect of fibroblast growth factor-2 is mediated through nuclear factor-kappaB activation induced via interaction between Akt and IkappaB kinase-beta in breast cancer cells.
Fibroblast growth factor-2 (FGF-2) is known for its mitogenic and motogenic effects on breast cancer cells. Here, we demonstrate that FGF-2 is also a potent stimulator of breast cancer cell survival, as it counteracts the apoptotic activity of the C2 ceramide analogue and various chemotherapeutic agents (5-fluorouracil, camptothecin, etoposide) in MCF-7, T47-D and BT-20 cells. The use of pharmacological inhibitors (PD98059, wortmannin, LY294002, SN50) and transfection with negative dominants (IkappaBm, p110(PI3K (phosphoinositide 3-kinase))*DeltaK, AktND) or small interfering RNA targeted against Akt indicated that PI3K/Akt and nuclear factor-kappaB (NF-kappaB), but not p42/p44 MAP-kinases, were required to stimulate FGF-2 antiapoptotic activity. The activation of NF-kappaB was dependent on PI3K/Akt, and using a combination of approaches based on immunoprecipitation, Western blotting and proteomics (two-dimensional electrophoresis and mass spectrometry), we identified the beta form of IkappaB kinase (IKKbeta) as a target of Akt signaling. The selective disruption of IKKbeta using small interfering RNA induced a potent inhibition of Akt-mediated activation of NF-kappaB and cell survival, indicating the functional involvement of IKKbeta in FGF-2 antiapoptotic signaling. Together, these results demonstrate Akt/IKKbeta interaction in NF-kappaB pathways, thereby emphasizing the potential of these proteins as therapeutic targets in breast cancer.
Vandermoere
Franck
F
ERI-8 INSERM, UPRES-EA-1033, batiment SN3, 59655 Villeneuve d'Ascq, France.
El Yazidi-Belkoura
Ikram
I
Adriaenssens
Eric
E
Lemoine
Jérôme
J
Hondermarck
Hubert
H
D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000378:metabolism*; D045744:Cell Line, Tumor; D015180:Electrophoresis, Gel, Two-Dimensional; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D051550:I-kappa B Kinase; D047468:Immunoprecipitation; D013058:Mass Spectrometry; D016328:NF-kappa B / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D014162:Transfection
D016328:NF-kappa B; D011518:Proto-Oncogene Proteins; D016222:Fibroblast Growth Factor 2; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; C496559:CHUK protein, human; D051550:I-kappa B Kinase; C496560:IKBKB protein, human; C496565:IKBKE protein, human