Metastatic potential of melanoma cells is not affected by electrochemotherapy

Electrochemotherapy is a local treatment combining chemotherapy and application of electric pulses to the tumour. Electrochemotherapy with bleomycin and cisplatin has already been found to be effective in controlling local tumour growth in the treatment of malignant melanoma. However, not much is known about the effect of electrochemotherapy on the metastatic potential of tumour cells. Prevention of metastasis is an important aspect of successful treatment. It is known that metastasis can be induced by different treatment modalities. Therefore, the aim of this study was to evaluate the effect of electrochemotherapy with cisplatin on the metastatic potential of human malignant melanoma cells. The cells treated by electrochemotherapy with cisplatin, were tested for their ability to migrate and invade through Matrigel coated porous membrane. There were no significant changes observed in cell migration and invasion after electrochemotherapy. Also, there were no changes observed in cell adhesion on Matrigel. Gene expression analysis demonstrated that very low number of genes was differentially expressed after electrochemotherapy with cisplatin. Two genes, LAMB3 and CD63 involved in cell migration, were both down-regulated after electrochemotherapy with cisplatin and the expression of metastasis promoting genes was not increased after electrochemotherapy. Our data suggest that electrochemotherapy does not increase metastatic behaviour of human melanoma cells. We analysed expression of genes involved in apoptosis and development of cancer in malignant melanoma cell line treated with cisplatin and cisplatin combined with electroporation in order to identify genes involved in cell line response. We used dual color approach. Each microarray contained at least 4 replicates of each gene and each condition was performed in at least two replicates, obtaining at least 8 measurements for each gene. Treated cell line was labeled with Cy5 and nontreated cell line was labeled with Cy3.