TEMPORAL ACQUISITION OF ENHANCED FIBRINOLYTIC-ACTIVITY BY SYRIAN-HAMSTER EMBRYO CELLS FOLLOWING TREATMENT WITH BENZO(A)PYRENE

  • 1 January 1977
    • journal article
    • research article
    • Vol. 37  (10) , 3815-3823
Abstract
Following treatment of Syrian hamster embryo cells with benzo(a)pyrene, the time required for the expression of enhanced fibrinolytic activity was examined. For this study, the fibrin-agarose overlay method was developed to distinguish the activity of normal and transformed colonies of hamster cells. Colonies possessing enhanced fibrinolytic activity were not observed 8 days after treatment, but they were observed following 1 passage (2 wk after treatment). Morphologically transformed colonies, which exhibited no enhanced fibrinolytic activity, were observed 8 days following treatment. In contrast to these 2 early changes, cells capable of growth in soft agar were observed later (6-8 wk after treatment). Untreated Syrian hamster embryo cells senesced and did not exhibit enhanced fibrinolytic activity. Approximately 1 of 10 untreated cultures escaped senescence and evolved as a continuous cell line. Such cultures frequently exhibited enhanced fibrinolytic activity. These results suggest that the acquisition of enhanced fibrinolytic activity, while perhaps not a cause of neoplastic transformation, may reflect a loss of control of the normal function of the cellular genetic apparatus during the process of transformation.