Human epithelial cells immortalized by human papilloma viruses.
Human papillomaviruses (HPVs) are small DNA viruses capable of inducing proliferation of epithelial cells in the natural hosts. The etiologic association between HPV and many forms of human cancer, especially squamous tumors of the anogenital region, has been generally recognized. Human epithelial cells transfected by high-risk-type HPV DNA can overcome apoptosis and become immortalized, but they are not capable of anchorage-independent growth or tumorigenic in nude mice, suggesting that they are premalignant and not malignant cells. These cells, due to their genetic instability, are liable to progress to anchorage-independent growth and tumorigenicity following subsequent genetic and epigenetic events. On the other hand, because immortalized epithelial cells represent an initial step in the multistep model of human carcinogenesis in vitro, they are useful in studies on the regulation by environment factors. Immortalized epithelial cells differ from normal epithelial and malignant carcinoma cells, in their response to various cytokines and growth factors, but their response is more like that of normal cells than of malignant cells. Understanding these processes may help design new therapeutic strategies to control tumor growth.
Zheng
J
J
Department of Virology, Haartman Institute, University of Helsinki, Finland.
Vaheri
A
A
D000818:Animals; D002471:Cell Transformation, Neoplastic; D002472:Cell Transformation, Viral / Q000235:genetics*; D016207:Cytokines / Q000502:physiology; D004279:DNA, Viral; D006133:Growth Substances / Q000502:physiology; D006801:Humans; D051379:Mice; D027383:Papillomaviridae / Q000235:genetics / Q000502:physiology*; D010641:Phenotype
D016207:Cytokines; D004279:DNA, Viral; D006133:Growth Substances