Tumour Necrosis Factor-α Upregulates Transferrin Receptors in K 562 Cells

Abstract

The effects of tumour necrosis factor-α on transferrin receptor expression in a human chronic myelocytic leukaemia cell line, K 562 cells, were studied. Cytofluorometry studies showed that the numbers of transferrin receptors in exponentially growing K 562 cells were increased when the cells were incubated with tumour necrosis factor-α for 24 h. The induction of transferrin receptors by tumour necrosis factor-α may be mediated by a mechanism that is independent of growth since cell growth in treated cultures did not differ from that in the controls. The DNA contents of K 562 cells treated with tumour necrosis factor-α showed that after 24 h there were less cells in the G1 and S phases and more cells in the G2/M phase than in the control group. The phase of upregulation of transferrin receptors induced by tumour necrosis factor-α may be dependent on the cell cycle. This new evidence that tumour necrosis factor-α upregulates transferrin receptors suggests a cancer-anaemia cascade in which the cancer burden state activates macrophage release of tumour necrosis factor-α as a result of transferrin receptor expression.