Epigallocatechin gallate suppresses lung cancer cell growth through Ras-GTPase-activating protein SH3 domain-binding protein 1.
Green tea is a highly popular beverage globally. Green tea contains a number of polyphenol compounds referred to as catechins, and (-)-epigallocatechin gallate (EGCG) is believed to be the major biologically active compound found in green tea. EGCG has been reported to suppress lung cancer, but the molecular mechanisms of the inhibitory effects of EGCG are not clear. We found that EGCG interacted with the Ras-GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) with high binding affinity (K(d) = 0.4 micromol/L). We also showed that EGCG suppressed anchorage-independent growth of H1299 and CL13 lung cancer cells, which contain an abundance of the G3BP1 protein. EGCG was much less effective in suppressing anchorage-independent growth of H460 lung cancer cells, which express much lower levels of G3BP1. Knockdown shG3BP1-transfected H1299 cells exhibited substantially decreased proliferation and anchorage-independent growth. shG3BP1 H1299 cells were resistant to the inhibitory effects of EGCG on growth and colony formation compared with shMock-transfected H1299 cells. EGCG interfered with the interaction of G3BP1 and the Ras-GTPase-activating protein and further suppressed the activation of Ras. Additional results revealed that EGCG effectively attenuated G3BP1 downstream signaling, including extracellular signal-regulated kinase and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase, in wild-type H1299 and shMock H1299 cells but had little effect on H460 or shG3BP1 H1299 cells. Overall, these results strongly indicate that EGCG suppresses lung tumorigenesis through its binding with G3BP1.
Shim
Jung-Hyun
JH
The Hormel Institute, University of Minnesota, Austin, MN 55912-3679, USA.
Su
Zheng-Yuan
ZY
Chae
Jung-Il
JI
Kim
Dong Joon
DJ
Zhu
Feng
F
Ma
Wei-Ya
WY
Bode
Ann M
AM
Yang
Chung S
CS
Dong
Zigang
Z
D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D015153:Blotting, Western; D002352:Carrier Proteins / Q000187:drug effects* / Q000378:metabolism; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D004265:DNA Helicases; D006801:Humans; D047468:Immunoprecipitation; D008175:Lung Neoplasms / Q000378:metabolism*; D000075223:Poly-ADP-Ribose Binding Proteins; D020365:RNA Helicases; D000067776:RNA Recognition Motif Proteins; D015398:Signal Transduction / Q000187:drug effects; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D018909:src Homology Domains / Q000187:drug effects / Q000502:physiology
D016588:Anticarcinogenic Agents; D002352:Carrier Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; D000067776:RNA Recognition Motif Proteins; D002392:Catechin; C045651:epigallocatechin gallate; D004265:DNA Helicases; C116070:G3BP1 protein, human; D020365:RNA Helicases