[Immunological study of induction of metallothionein in bladder cancers]

Metallothionein (MT) in tumor cell has been indicated as one of the factors involved in the mechanism of resistance to anticancer drugs. The relationship between expression of MT and chemotherapy with anticancer drugs was studied with bladder cancer culture cell lines and tissue samples from clinical cases. In drug-resistance cell lines, MT expression was studied by immunohistological staining of the avidin -biotin peroxidase complex (ABC) method, and by the radioimmunoassay (RIA) method, using an anti-MT antibody. As for tissue samples from clinical cases, 114 paraffin embedded samples of 29 cases before and after chemotherapy were subjected to immunohistological staining of MT. Human-bladder cancer cell lines with resistance to anticancer drugs (C1-7/CDDP, T-24/ADM) showed increased of expression of MT compared to each parental cell lines (C1-7, T-24), suggesting relationship of resistance to anticancer drugs and MT expression. In the clinical cases, those with continuous administration such as intra-vesicle chemotherapy or oral administration chemotherapy showed greater incidence of positive staining of MT expression in comparison with cases with fewer administrations, such as intra-arterial infusion therapy or intravenous administration chemotherapy. These results demonstrated that repetitive and continuous administration of anticancer drugs cause increase of MT in bladder cancer cell, which may be a possible mechanism of acquired resistance to anticancer drugs.