ABSTRACT
We studied malignant melanoma cell line Me45 and human ovarian carcinoma cell line SKOV-3 (resistant to cisplatin, adriamycin and diphtheria toxin), assessing their expression level of p53, HSP70 and glutathione S-transferase GST-π before and after chemotherapy with cisplatin. These proteins may be responsible for the occurrence of chemoresistance in cancer patients. To assess protein expression we used the immunocytochemical Avidin-Biotin-peroxidase Complex (ABC) method. Before application of chemotherapy, proteins p53, HSP70 and GST-π were present in 100 % of the examined melanoma cells. After the treatment, the intensity of the immunocytochemical reaction for p53 increased, whereas the intensity of immunocytochemical staining for HSP70 and GST-π decreased. In SKOV-3 cells, p53 and HSP70 were present in 100 % of the examined cells both prior to chemotherapy and after it. However, the intensity of the immunocytochemical reaction for p53 decreased, while that of HSP70 increased. As regards GST-π, only 5 % of all examined SKOV-3 cells revealed its expression before chemotherapy. Incubation with cisplatin caused an elevation in the number of ovarian cancer cells expressing GST-π up to 50 %. Moreover, the intensity of the immunocytochemical reaction for GST-π significantly increased.
