Abstract A231: Let 7a regulates IL-6 expression in malignant mesothelioma

IL-6-dependent signaling pathway leading to Stat3 phosphorylation is reported to be involved in malignant phenotype of mesothelima. Altered expression of microRNA (miR) is observed in many cancers, however, the mechanism how miR regulates IL-6 expression in masothelioma is still unknown. We performed immunohistochemistry for phosphorylated Stat3 (pStat3) in 12 human mesotheliomas. Next, using 7 mesothelioma cell lines, mRNA expression of IL-6 and IL-6R, together with several miRs that regulated IL-6, and Stat 3 phosphorylation were examined by RT-PCR and immunoblotting. Five of 12 mesotheliomas showed strong expression of pStat3 in their nuclei and let 7a was identified as one of the candidate molecules that regulate IL-6 expression in mesothelioma by using 3’UTR reporter system. Moreover, IL-6 was found to regulate miR-153, miR-340, and miR-410 expressions. These findings suggest that let 7a, miR-153, -340, and 410 may be involved in malignant phenotype through regulation of IL-6 pathway in mesothelioma. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A231. Citation Format: Mishie A. Tanino, Shinji Kohsaka, Kazuhiro Yachi, Masumi Tsuda, Taichi Kimura, Hiroshi Nishihara, Shinya Tanaka. Let 7a regulates IL-6 expression in malignant mesothelioma. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A231.