M14K and M38K malignant pleural mesothelioma cell lines preserve the same claudin-based phenotype in vivo.

BACKGROUND Malignant pleural mesothelioma (MPM) is an aggressive neoplasm with few treatment options. Reliable tumour cell lines for mesothelioma research are rare. Claudins seem to be attractive targets for cancer therapy. AIM To establish a claudin-based MPM phenotype and to verify whether it is preserved in vitro and in vivo. MATERIALS AND METHODS Claudin-3 and -4 expression was examined by immunohistochemistry and immunoblotting in MPM (n=15) and lung adenocarcinoma (n=5) specimens. Claudin-3, -4 and -15 expression was also assessed in MPM versus adenocarcinoma cell lines and in MPM versus adenocarcinoma-derived tumour xenografts mouse models. RESULTS A defined MPM phenotype was established: M14K and M38K cell lines highly express Claudin-15 and calretinin but not claudin-3 nor claudin-4. Similar results were obtained in xenograft mouse models. CONCLUSION M14K and M38K cell lines, whether in vitro or in an animal model are representative models and appropriate in exploring new therapeutic strategies in MPM that may target claudins.