| Popis: |
We have investigated whether Group B human adenoviruses (Ad) (Ad3, Ad7, Ad11, Ad14, Ad16, and Ad21), which are widespread in the human population and are tumorigenic in hamsters, may play a role in human cancer. Hybridization of Ad7-radiolabeled DNA with DNA's from an Ad7-induced primary hamster tumor and from two cell lines (5728 and Ad7 P-cell) established from Ad7-induced hamster tumors indicated multiple copies per cell of 17, 30 to 36, and 20%, respectively of the Ad7 genome. Thus, cells transformed by Group B Ads resemble cells transformed by Group C and Group A Ad's in that they retain multiple copies of a variable fraction of the viral genome. These model studies suggest that possible Group B Ad-induced human cancer cells should contain one or more copies of virus DNA per cell. Therefore, we assayed human cancer DNA's for Ad sequences, by highly sensitive "saturation-hybridization" reactions with Ad7 or Ad11 DNA (4 X 10(6) to 2.1 x 10(8) cpm/microgram). We concentrated on cancers of the respiratory and digestive systems, because these systems are the most common sites of infection by Group B Ad's. In 8 independent experiments, no Ad7 sequences were detected in DNA's from 16 normal lung tissues, 18 normal tissues of the digestive system, 34 cancers of the respiratory system, 19 cancers of the digestive system, 11 cancers of the urinary system, 5 cancers of the genital system, 3 cancers of the breast, and 6 Hodgkin's lymphomas. Reconstruction controls with added Ad7 DNA indicated that about 0.05 to 0.1 copy of Ad7 DNA per cell should be detected. Ad11 is strongly implicated as a cause of acute hemorrhagic cystitis. In two independent experiments, no Ad11 sequences were detected in DNA's from 9 carcinomas of bladder, 10 carcinomas of prostate, 24 carcinomas of kidney, 3 hypernephromas, 3 Wilms' tumors, or 2 normal kidneys. Reconstruction experiments indicated that the cancer DNA assays had a sensitivity of 0.05 to 0.1 copy of Ad11 DNA per cell. The DNA's of Group B Ad's are greater than 85% homologous by hybridization; thus, these results are applicable to all Group B serotypes. Our data provide evidence (but not formal proof) that none of the human cancers that we analyzed were induced by Group B Ad's. These tumors represent about 50% of the tumors that affect humans. The possible involvement of Group B Ad's in other less common forms of human cancers is under investigation in our laboratory. |
