Summary.-Collagen-peptidase activity in extracts of HeLa cells and human tumours is inactivated by Razoxane (ICRF-159), cyclophosphamide, 5-fluorouracil, thiotepa, aprotinin, EDTA and phenanthroline. As this activity, in association with other enzymes, may contribute to tissue lysis in cancers, chemical intervention may reduce invasiveness and modify the processes of infiltration and metastasis. Accordingly, some drugs used in therapy or for the prevention of metastasis may produce their observed effects by a combination of factors including enzyme inhibition.
Summary.-HeLa cells in culture do not accumulate ascorbic acid unless ascorbic acid or dehydroascorbic acid is available in the medium. Collagen peptidase corresponding to the activity found in the invasive zone of tumours, and acid phosphatase, in HeLa cells cultured under normal conditions, are unaffected by ascorbic acid, but are reduced in cells deprived of carbohydrate. These reduced collagen-peptidase levels, but not acid phosphatase, are restored to the values of normal HeLa cells by ascorbic acid. The relevance of these findings is considered in the context of tumour growth and spread.
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