The ultrastructural effects and immunolocalisation of fumonisin B 1 on cultured oesophageal cancer cells SNO

Abstract

Numerous investigations have shown that fumonisin B1 (FB 1) is the causal agent in a range of animal toxicities, including leucoen- cephalomalacia, pulmonary oedema and renal and hepatic cancer in rats and mice. Fumonisin B, has also been implicated in the aetiology of oesophageal cancer in South Africa. Human data are lacking, however, and the International Agency for Research on Cancer has accordingly classified this mycotoxin as a Type 2B carcinogen. This study investigated the ultrastructural effects of FB1 cytotoxicity on a human oesophageal carcinoma cell line (SNO). The pathological changes induced by FB, were determined using transmission and scanning electron microscopy. Immuno- cytochemistry was used to immunolocalise FB, (monoclonal anti-FB, ) within the cells. The results showed marked pathological changes that included enlargement or microsegregation of the nucleus, microsegregation of the nucleolus, and swelling and elongation of mitochondria, as well as signs of membrane damage. These cytotoxic effects were associated with the action of FB, since the toxin was internalised in nuclei, mitochondria and the cytoplasm of affected cells. This study shows that FB, may exert its biological effects in SNO cells through binding to cellular macromolecules or membrane components within the affected organelles.