Naphtho[1,2-b]furan-4,5-dione inactivates EGFR and PI3K/Akt signaling pathways in human lung adenocarcinoma A549 cells.
OBJECTIVE
Naphtho[1,2-b]furan-4,5-dione (NFD), prepared from 2-hydroxy-1,4-naphthoquinone and chloroacetaldehyde in an efficient one-pot reaction, exhibits an anti-carcinogenic effect. This study was performed to elucidate whether EGFR and PI3K signaling pathways are involved in NFD-induced apoptosis of human lung adenocarcinoma A549 cells.


METHODS
The effect of NFD on cell viability and apoptosis was measured by the MTT assay and flow cytometry. The phosphorylation levels of EGFR and its regulatory molecules by NFD treatment were studied by immunoblots.


RESULTS
Immunoblot showed that NFD inhibited EGFR phosphorylation and the activation of PI3K/Akt, downstream molecules of EGFR pathway, in A549 cells. The levels of downstream targets of Akt, including phospho-glycogen synthase kinase-3beta (p-GSK-3beta), GSK-3beta, forkhead transcription factor (FKHR), and cyclin D1, were also reduced after NFD treatment. Moreover, inactivation of nuclear factor-kappaB (NFkappaB), modulation of IkappaKalpha/beta and IkappaBalpha, up-regulation of Bad and Bax, and down-regulation of anti-apoptotic proteins including phospho-Bad, Bcl-2, survivin, and XIAP were also found in NFD-treated cells. In addition, NFD treatment disrupted mitochondrial membrane potential (DeltaPsim) and resulted in release of mitochondrial cytochrome c and activation of both caspases-9 and caspase-3.


CONCLUSIONS
These findings indicate that EGFR and PI3K/Akt signaling pathways play important roles in NFD-induced apoptosis of A549 cells.
Su
Jung-Chen
JC
Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan, ROC.
Lin
Kuei-Li
KL
Chien
Ching-Ming
CM
Tseng
Chih-Hua
CH
Chen
Yeh-Long
YL
Chang
Long-Sen
LS
Lin
Shinne-Ren
SR
D000230:Adenocarcinoma / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D045304:Cytochromes c / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology / Q000378:metabolism; D066246:ErbB Receptors / Q000096:biosynthesis* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D008175:Lung Neoplasms / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism; D015394:Molecular Structure; D009285:Naphthoquinones / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000096:biosynthesis* / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000096:biosynthesis* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
D000970:Antineoplastic Agents; D009285:Naphthoquinones; C073873:naphtho(1,2-b)furan-4,5-dione; D045304:Cytochromes c; D019869:Phosphatidylinositol 3-Kinases; C512478:EGFR protein, human; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt; D053148:Caspase 3; D053453:Caspase 9