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Journal of Cancer Research and Clinical Oncology

, Volume 126, Issue 10, pp 589–594 | Cite as

Study of immortalization and malignant transformation of human embryonic esophageal epithelial cells induced by HPV18 E6E7

  • Zhongying Shen
  • Shan Cen
  • Jian Shen
  • Weijia Cai
  • Jinjie Xu
  • Zhiping Teng
  • Zhi Hu
  • Yi Zeng
ORIGINAL PAPER

Abstract

In order to study the effect of viruses and tumor promoters on the tumorigenicity of the esophagus, human embryonic esophageal epithelial cells were infected with human papilloma virus HPV18 E6E7-AAV in synergy with 12-O-tetradecanoylphorbol 13-acetate (TPA) to observe their malignant transformation. The cultured esophageal epithelial cells incubated with HPV18 E6E7-AAV were divided into two groups: the SHEEC1 group was exposed to TPA (5 ng/ml) for 4 weeks at the 5th passage of the cells; the SHEE group served as the control and was cultured in the same medium without TPA. The morphological phenotype, the DNA content during the cell cycle and the chromosomes were analyzed. The tumorigenicity was assessed by colony formation after cultivation in soft agar and transplanting the cells into nude mice. HPV18 E6E7 DNA was assayed by fluorescent in situ hybridization (FISH) and the polymerase chain reaction (PCR). The SHEE group, at its 20th passage, grew as a monolayer with the cells showing anchorage dependence and contact inhibition. The chromosome analysis showed diploidy, and soft-agar cultivation and injection into nude mice showed the cells to be non-tumorigenic. They were therefore immortalized cells. In contrast, the SHEEC1 group (TPA group) showed increased DNA synthesis and a proliferative index that was higher (45%) than that of the SHEE group (34%). The number of large colonies of dense multilayer cells (positively transformed foci) in soft agar was high in SHEEC1 group (4.0%) but low in the SHEE group (0.1%). Tumors resulting from transplantation were observed in all six nude mice injected subcutaneously with cells of the SHEEC1 group but no tumor developed in mice receiving cells of the SHEE group. In both groups of cells, HPV18 E6E7 DNA was positively detected by FISH and PCR. The malignant transformation of human embryonic epithelial cells was induced in vitro by HPV18 E6E7 in synergy with TPA. This is a good evidence for the close relationship between HPV and the etiology and pathogenicity of esophageal carcinoma. It is also a reliable model for studying the cellular and molecular mechanisms of carcinogenesis of esophageal carcinoma.

Key words Human embryonic esophageal epithelium HPV18 E6E7 genes Immortalization TPA Malignant transformation 
AbbreviationsHPV Human papilloma virus TPA 12-O-tetradecanoylphorbol 13-acetate HEK Human kidney epithelium 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • Zhongying Shen
    • 1
  • Shan Cen
    • 2
  • Jian Shen
    • 1
  • Weijia Cai
    • 1
  • Jinjie Xu
    • 1
  • Zhiping Teng
    • 2
  • Zhi Hu
    • 1
  • Yi Zeng
    • 2
  1. 1.Department of Tumor Pathology, Medical College of Shantou University, Shantou 515031, Guandong, P. R. China Fax: +86-754-8537516CN
  2. 2.Institute of Virology, Chinese Academy of Preventive Medicine, Beijing 100052, ChinaCN

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