Inhibition of HeLa Cell Proliferation by 4-Hydroxynonenal is Associated with Enhanced Expression of the c-fos Oncogene

Previous studies have shown that the highly reactive aldehyde 4-hydroxynonenal (HNE), a mediator of oxidative stress, can either stimulate or inhibit cell proliferation, depending on the concentration of the aldehyde and the presence of serum. HNE can also induce differentiation of tumour cells in vitro and inhibit the tumour development in vivo. The aim of the study presented was to find out more details about the basic mechanisms by which HNE influences cell growth behaviour. Therefore we analysed the effect of HNE on the transcription of the c-fos gene in HeLa cells, to clarify the pathway by which the aldehyde modulates gene transcription and growth behaviour of the cells. At a supraphysiological concentration (50 μM) the aldehyde caused an enhanced c-fos transcription (as measured by the reverse transcriptase/polymerase chain reaction assay), while it inhibited cell proliferation markedly. Therefore, we assume that among the "early" effects of HNE on cellular growth regulation might be an altered expression of the "early response" genes (c-fos), while a "late" effect might be an altered autocrine/paracrine growth regulatin of the cells. This finding on the possible basic mechanisms of the biological effects of HNE together with the already described high toxicity of the aldehyde for cancer cells give support for the further evaluation of the possible use of HNE in cancer biotherapy.