[Transforming effect of PDGFRA gene mutant on the cell function in gastrointestinal stromal tumor].
OBJECTIVE
To explore the effect of malignant transformation of the L839P, a new mutation site of the PDGFRA gene, on the pathogenesis of gastrointestinal stromal tumors.


METHODS
All recombinant plasmids were stably transfected into CHO cells by liposomes. Western blotting was used to detect the expression of PDGFRA protein. The cell growth curve was plotted by cell counting. Flow cytometry was used to detect the cell cycle and apoptosis of CHO cell, respectively. The stably transformed cells were inoculated subcutaneously into the back of nude mice and the mice were used to observe the tumorigenesis. Transient transfection of the mutant-type plasmids of PDGFRA gene and the wild-type plasmids of kit gene into the CHO cells was performed. Western blot was used to detect the expression of kit protein and its phosphorylated forms.


RESULTS
PDGFRA protein expressed in the negative control, experimental group and positive control, except the empty vector. The growth curve showed that it was accelerated in the experimental group and positive control. The ratios of cells in proliferative phase were 28.4% (blank), 24.5% (negative control), 43.8% (experimental group) and 40.9% (positive control). Their apoptotic indexes were 1.8%, 1.9%, 1.5% and 1.6%, respectively. After three weeks, tumors were observed in the nude mice of experimental group and positive control, inoculated with the stably transformed cells. Moreover, the expression of phosphorylated protein of kit was enhanced after cotransfection of the mutant-type plasmids of PDGFRA and the wild-type plasmid of kit.


CONCLUSIONS
The PDGFRA mutant L839P is a gain-of-function mutation and has obviously malignant transforming effect on normal cells, and may activate kit protein accelerating the tumorigenesis. Gastrointestinal stromal tumors;
Yang
Lei
L
Department of Pathology, Institute of Cardiothoracic Surgery, Changhai Hospital, Second Military Medical University, Shanghai 200433, China.
Bai
Chen-Guang
CG
Hou
Xiao-Wei
XW
Liu
Xiao-Hong
XH
Ma
Da-Lie
DL
D000818:Animals; D017209:Apoptosis; D016466:CHO Cells; D002453:Cell Cycle; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D006224:Cricetinae; D003412:Cricetulus; D046152:Gastrointestinal Stromal Tumors / Q000209:etiology / Q000235:genetics* / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D009154:Mutation; D010957:Plasmids; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics* / Q000378:metabolism; D014162:Transfection
D019009:Proto-Oncogene Proteins c-kit; D020796:Receptor, Platelet-Derived Growth Factor alpha