[Correlation of GLC-82 lung carcinoma cell aggregation in suspension culture to the activation of protein kinases FAK, AKT, ERK, and SRC].
OBJECTIVE
Our previous study revealed that tyrosine kinase FAK can partly mediate the aggregation of tumor cells in suspension culture, therefore, suppress cell apoptosis and promote cell proliferation. However, the downstream pathway of FAK in the formation of cell aggregation is unclear. This study was to investigate the roles of FAK and its potential downstream molecules ERK, AKT, and SRC in mediating aggregation of lung adenocarcinoma GLC-82 cells in suspension culture.


METHODS
Morphology of the aggregations of GLC-82 cells and normal lung HBE cells in polyHEMA suspension culture was observed. Cell apoptosis was studied by DNA electrophoresis on agarose gel. The ability of cell transformation was studied by colony formation assay. The phosphorylation of the protein kinases was investigated by Western blot. FAK was silenced by RNA interference.


RESULTS
GLC-82 cells survived and aggregated in suspension culture; while apoptosis occurred in HBE cells which formed no aggregation in suspension culture. Phosphorylation levels of FAK, ERK, AKT, and SRC were related to GLC-82 cell aggregation. FAK silencing partly blocked the formation of GLC-82 cell aggregation, and decreased the phosphorylation levels of ERK and AKT; the colony formation rate in soft agar was significantly lower in GLC-82 cells with FAK silencing than in GLC-82 cells without FAK silencing [(12.2+/-1.1)% vs. (3.6+/-0.7)%, P=0.001].


CONCLUSIONS
The formation of GLC-82 cell aggregation is partly mediated by FAK signal pathway, and ERK and AKT are the downstream molecules of FAK.
Fang
Yi
Y
State Key Laboratory of Oncology in Southern China, Guangzhou, Guangdong, P. R. China.
Zhang
Xing
X
Zhang
Ji-Ren
JR
Jiang
Wen-Qi
WQ
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology*; D017209:Apoptosis; D002449:Cell Aggregation / Q000502:physiology*; D018929:Cell Culture Techniques / Q000379:methods; D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D020868:Gene Silencing; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology*; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism*; D015398:Signal Transduction
D051416:Focal Adhesion Protein-Tyrosine Kinases; D016392:Proto-Oncogene Proteins pp60(c-src); D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases