In vitro targets of recombinant human tumour necrosis factor-a: blood flow, oxygen consumption and growth of isotransplanted rat tumours

Author(s): Schaefer, C., Tyler, G., Vaupel, P.

Journal/Book: British Journal of Cancer. 1989; 60: 555-560.

Abstract: The impact of recombinant human tumour necrosis factor-alpha (1µg kg-1 to 1mg kg-1; 6.6 x 10 6 U mg protein-1) on blood flow, oxygen consumption and growth of a moderately TNF-sensitive rat tumour (DS-carcinosarcoma) was studied. Tumour growth was stimulated at low TNF doses (1 and 1O µg kg-1) and significantly retarded at higher TNF dose levels (0.1 and 1 mg kg-1). Growth changes were concomitant with variations in oxygen consumption, lactate release and acidification of the metabolic micromilieu. Both single and repeated application of low TNF doses (1 10 µg kg-1 i.v.) increased tumour perfusion whereas single administration of high TNF dose levels (0.1 1 mg kg-1 i.v.) reduced tumour blood flow. After repeated application of high TNF doses tumours shrank to such small sizes that perfusion measurements could not be performed within the observation period of two weeks. It is concluded that TNF effects on solid tumours are at least partially mediated by changes in tumour perfusion. Thus, an altered tumour sensitivity towards other treatment modalities, e.g. irradiation, chemotherapy or hyperthermia, can be expected after TNF therapy. A beneficial TNF effect would critically depend on the dose level employed and on the sequence and timing of various combination regimes.

Keyword(s): TNF

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