Abstract 3976: Targeted delivery of a synthetic microRNA-based mimic as an approach to cancer therapy

MicroRNA expression is commonly suppressed in cancer, contributing to tumor cell biology. Recently we demonstrated that multiple members of the miR-15/16 family are downregulated and have tumor suppressor functions in malignant pleural mesothelioma (MPM), an asbestos-related cancer for which few treatments are available. These results are similar to previous findings in prostate and non-small cell lung cancer (NSCLC). Using mimics to restore levels of miR 15a, miR-15b or miR-16 led to growth inhibition and induction of apoptosis of MPM cells in vitro. The miR-16 mimic, packaged in bacterially-derived, EGFR antibody-targeted, EDV(TM)nanocells, inhibited xenograft tumor growth in vivo. As multiple microRNAs from the same family are downregulated in MPM, we investigated whether a single synthetic mimic based on the consensus sequence of all family members could restore activity of the entire family. To this end we generated four novel mimics derived from the consensus sequence of the miR-15/16 family and tested them in a range of tumor cell lines. Compared with a mimic corresponding in sequence to native miR-16, the consensus mimics had enhanced growth inhibitory activity in MPM, NSCLC and prostate cancer lines, three tumor types in which miR-15/16 expression is suppressed. They were also active in cell lines derived from breast and colon cancer. When packaged in minicells, the synthetic mimics inhibited growth of MPM xenograft tumors in vivo. Based on these preclinical studies ...
Source: Cancer Research - Category: Cancer & Oncology Authors: Tags: Molecular and Cellular Biology Source Type: research