Upregulated expression of Ezrin and invasive phenotype in malignantly transformed esophageal epithelial cells

AIM: To investigate the correlation between ezrin expression and invasive phenotype formation in malignantly transformed esophageal epithelial cells. METHODS: The experimental cell line employed in the present study was originated form the progressive induction of a human embryonic esophageal epithelial cell line (SHEE)by the E6E7 genes of human papillomavirus (HPV) type 18.The cells at the 35th passage after induction called SHEEIMM were in a state of immortalized phase and used as the control,while that of the 85th passage denominated as SHEEMT represented the status of cells that were malignantly transformed. The expression changes of ezrin and its mRNA in both cell passages were respectively analyzed by RT-PCR and Western blot. Invasive phenotype was assessed in vivo by inoculating these cells into the severe combined immunodeficient (SCID) mice via subcutaneous and intraperitoneal injection, and in vitro by inoculating them on the surface of the amnion membranes, which then was determined by light microscopy and scanning electron microscopy. RESULTS: Upregulated expression of ezrin protein and its mRNA was observed in SHEEMT compared with that in SHEEIMM cells. The SHEEMT cells inoculated in SCID mice were observed forming tumor masses in both visceral organs and soft tissues in a period of 40 days with a special propensity to invading mesentery and pancreas, but did not exhibit hepatic metastases. Pathologically, these tumor cells harboring larger nucleus, nucleolus and less cytoplasm could infiltrate and destroy adjacent tissues. In the in vitro study,the inoculated SHEEMT cells could grow in cluster on the amniotic epithelial surface and intrude into the amniotic stroma. In contrast, unrestricted growth and invasiveness were not found in SHEEIMM cells in both in vivo and in vitroexperiment. CONCLUSION: The upregulated ezrin expression is one of the important factors that are possibly associated with the invasive phenotype formation in malignantly transformed esophageal epithelial cells.

Separation and identification of differentially expressed nuclear matrix proteins between human esophageal immortalized and carcinomatous cell lines

AIM: To separate and identify differentially expressed nuclear matrix proteins (NMPs) between the immortalized human esophageal epithelial cell line (SHEE) and the malignantly transformed esophageal carcinoma cell line (SHEEC), and to provide new ways for finding specific markers and the pathogenesis of esophageal carcinoma.METHODS: SHEE and SHEEC cell lines were used to extract NMPs. The quality of NMPs was monitored by Western blot analysis including DNA topoisomerase Ⅱα, proliferation cell nuclear antigen (PCNA) and histone. NMPs of SHEE and SHEEC were analyzed by two-dimensional electrophoresis (2-DE), silver staining and PDQuest6.2 image analysis software. Three spots in which the differentially expressed NMlPs were more obvious, were selected and analyzed with matrix-assisted laser desorption/ionization time of flying mass spectrometry (MALDI- TOF-MS) and database search.RESULTS: Western blot analysis revealed that DNA topoisomerase Ⅱα and PCNA were detected, and the majority of histones were deleted in NMPs of SHEE and SHEEC. After 2-DE image analysis by PDQuest6.2 software, the 2-DE maps were detected with an average of 106±7.1 spots in SHEE and 132±5.0 spots in SHEEC. Most of them were matched one another (r=0.72), only 16 protein spots were found differing in intensity. Three NMPs including cytoskeletal tropomyosin,FK506bindingprotein6,similartoretinoblastoma binding protein 8 were preliminarily identified by MALDI- TOF-MS.CONCLUSION: These differentially expressed NMPs may play an important role during malignant transformation from SHEE to SHEEC. Their separation and identification will contribute to searching for specific markers and probing into the pathogenesis of esophageal carcinoma.