The Effect of Overexpressed Beclin 1 on Esophageal Cancer (Eca109) Cells in vivo

Abstract: Autophagy is an evolutionarily conserved lysosomal degradation pathway， and activation of autophagy may function as a tumor suppressor by degrading defective organelles and other cellular components. Beclin 1 is a main actor of autophagy， also known as a tumor suppressor gene. In the present study， we examined the expression of Beclin 1 in esophageal cancer by immunohistochemical SP method， Beclin1 recombinant plasmid pIRES2-ZsGreen1-hBeclin 1 was constructed and transfected into Eca109 cells. Autophagy was observed under electron microscopy. The expression of Beclin 1 at mRNA level was detected by the reverse transcriptionpolymerase chain reaction (RT-PCR)， and Western blot was used to examine the protein expression of Beclin 1， Bcl-2 and P53. Moreover， in vivo， the proliferation of the cancer cells was evaluated in xenotransplant nude mice model. The results showed that reduced Beclin 1 expression was observed in esophageal cancer cells than in normal tissues(P<0.05). We successfully constructed Beclin 1 recombinant plasmid and transfected it into Eca109 cells， autophagosomes were widely formated. The results of RT-PCR and Western blot showed that the expression of Beclin 1 was remarkably higher in transfected group ECA109 cells at both mRNA and protein levels than that of control group and untransfected group. In addition， the protein expression of Bcl-2 was down-regulated but P53 up-regulated after transfected. In vivo， the average weight and volume of tumor in Beclin 1 transfection group xenografts mice were significantly lower than those in the control group (P<0.05). The result suggested that Beclin 1 gene can well inhibit esophageal cancer， and this lay the foundation for targeted therapy for esophageal cancer.

CSTR: 32200.14.cjcb.2013.03.0007