engleski

Iron influence on E6/E7 oncogene expression in cervical carcinoma cells

We have shown earlier that the non toxic, iron-containing, anti-anaemic drug ferric-sorbitol-citrate complex - FSC (Jectoferâ, Astra, Linz), inhibited proliferation of cultured GHC, KB, CaCo2, Hep2, MiaPaCa2 and HeLa cell lines but did not affect the proliferation of the non-malignant fibroblast cell lines L929, HEF522, and Wi38. While iron plays a critical role in several essential oxidation-reduction systems within the cell the complex mechanism of iron influence on tumour cell proliferation is not entirely understood. As iron may participate in the pathogenesis of viral infections and cancer in several ways, the aim of this study was to monitor E6/E7 oncogene expression in two cervical carcinoma cell lines, HeLa containing HPV18, and SiHa containing HPV16 in respect to iron treatment. Cells were treated with four different concentrations of iron (since 10-6 to 10-3 M FSC-Fe). We used GAPDH (housekeeping gene) expression as an internal control for E6/E7 expression level comparison. RNA isolation was performed 3h, 24h and 48h after cell treatment. After isolation and concentration measurement, RNA was reversely transcribed to cDNA, which is further used for E6/E7 oncogene expression analysis. Oncogene expression was analyzed in respect to different treatment. Influence of FSC on cell growth was measured by MTT assay, 24h, 48h and 72h after treatment. In that case as a control cells A431 cervical carcinoma cell lines without HPV was used. Experiments were performed in quadruplicates, and differences were analysed by Student's t-test. The FSC was very potent in inhibiting the growth of HeLa and A431 cells. The most pronounced growth inhibitory effect was observed on A431 cells (under 60%). Jectoferâ (in all concentrations) did not diminish the growth of SiHa cells. The strongest difference of the drug action was discovered after treatment for 72 hours. Oncogene E6/E7 expression in HeLa and SiHa cells depends on iron concentration and the time of cells treatment. Control of tumour cell growth through perturbation of cellular iron metabolism is a potentially important strategy in the treatment of cancer and thus warrants continued investigation. The FSC is very interesting in that field because of their specific anti tumour effect. The obtained results indicate that iron treatment may not only have an anti tumour effect but in the case of some types of cervical carcinoma could have an important role in the HPV associated oncogenesis.

iron; cancer

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