Viral carcinogenesis.
نویسنده
چکیده
Viral carcinogenesis presents many problems which are the object of very active investigation; to condense in a lecture the present status of all these problems and to do justice to them would be impossible; I shall therefore limit the discussion to a few of them, which concern mainly the mechanism of carcinogenesis by viruses. In this discussion the at tent ion will be focused on experimental results obtained in vitro, since these can be evaluated in a simpler and more direct way than results obtained in organisms. Most of the experimental work to be referred to was carried out by using the DNA-containing polyoma virus and cultures of Syrian hamster or mouse embryo. We shall therefore first summarize the relevant characteristics of this system. Within 3 or 3 weeks following infection with polyoma virus, the hamster cultures undergo a progressive conversion characterized by the replacement of the normal cells with cells of a new type, having special morphological and growth characteristics. In fact the normal cells are broadly fusiform and well spread on the solid substrate on which they are cultivated; in crowded cultures they are more elongated and often assume a parallel arrangement in well ordered bundles. After forming a continuous cellular rnonolayer these cells do not grow any further, al though sometimes two bundles of cells may intersect each other a t an angle: thus the cultures are essentially two-dimensional. Descriptively, these cultures can be defined as "regulated." On the contrary, the cells of the converted cultures are much more elongated; they grow at all stages without any regular arrangement: the orientation in respect to each other is nearly random. In crowded cultures the cells form a threedimensional felt constituted by many layers of criss-crossing cells. In contrast to normal cells, they can be described as "non-regulated."
منابع مشابه
Interaction of viral oncogenic proteins with the Wnt signaling pathway
It is estimated that up to 20% of all types of human cancers worldwide are attributed to viruses. The genome of oncogenic viruses carries genes that have protein products that act as oncoproteins in cell proliferation and transformation. The modulation of cell cycle control mechanisms, cellular regulatory and signaling pathways by oncogenic viruses, plays an important role in viral carcinogenes...
متن کاملThe biology of viral carcinogenesis.
Virus induction of tumors is the direct effect of a complex interaction of a single virus particle with the target cell. The factor which determines which virus has the potential for inducing tumors resides in the viral nucleic acid and of neces sity must be related to the chemical structure of the viral genome. It has been suggested that the important chemical structure is a sequence of bases ...
متن کاملRegulation of viral oncogenesis by microRNAs
Viral infection may play a causative role in human cancers, for example hepatitis B virus (HBV) or hepatitis C virus (HCV) in liver cancer, human papilloma virus (HPV) in cervical cancer, and Epstein-Barr virus (EBV) in nasopharyngeal carcinoma. Virally infected cells express viral-encoded genes that are critical for oncogenesis. Some viruses also encode microRNA (miRNA) species. miRNAs are sma...
متن کاملThe effects of ultraviolet light irradiation on viral infections.
Exposure to ultraviolet radiation is associated with the development of cutaneous carcinomas, and with suppression of immune responses to a variety of antigens, including those of fungal, bacterial and parasitic origin, and contact sensitizers. UV irradiation also influences viral infections. It can affect viral mutation, the photolocalization of viral exanthems, viral oncogenesis, activation o...
متن کاملmiRNA as viral transcription tuners in HPV-mediated cervical carcinogenesis.
High-risk human papillomaviruses (HPVs) are oncogenic DNA viruses that promote carcinogenic signaling by their oncoproteins mainly E6 and E7. A well-defined promoter regulates expression and enhancer region on HPV genome containing number of cis elements that essentially require a set of cognate host transcription factors to regulate viral promoter gene activity. Expression of these host factor...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Cancer research
دوره 21 شماره
صفحات -
تاریخ انتشار 1961