报告题目：Recombinant tRNA/mir-34a as a novel therapeutic reagent for cancers

报 告 人：汪维鹏 副教授（苏州大学药学院药物分析学教研室）

报告时间：2014年6月20日（星期五）上午10:00

报告地点：独墅湖校区二期云轩楼2301室

ABSTRACT

Cancer is the product of various genetic and epigenetic changes and requires interference with multiple oncogenic pathways for successful intervention. The therapeutic use of microRNA (miRNA), a class of non-coding RNA, has gained much attention because its mechanism of action is in line with our current thinking of cancer as a multiple-pathway disease. Indeed, a liposome formulated miR-34a mimics, namely “MRX34”, has entered Phase I clinical trial for the treatment of primary liver cancer or those with liver metastasis from other cancers. However, even organic synthesis of oligonucleotides may be automated, a therapeutic dose of 22-nt small RNA agents is astonishingly costly (e.g., 10 mg miRNA mimics estimated to be around $10,000). Therefore, we developed a tRNA-based recombinant RNA technology to produce large quantities of inexpensive, naturally-occurring, and biologically-functional pre-miR-34a (tRNA/mir-34a) in E.coli cells and then purified it to high homogeneity by using fast performance liquid chromatography (FPLC) technique. The purity, molecular weight, primary sequences, and posttranscriptional modifications of the isolated tRNA/mir-34a were analyzed by liquid chromatography-mass spectrometry (LC-MS). Then, we found that tRNA/mir-34a was processed into mature miR-34a by endoribonuclease Dicer in human carcinoma cells in a dose- and time-dependent manner, and was active in repressing protein expression of miR-34a target genes CDK6, SIRT1, and MET in both A549 and HepG2 carcinoma cells. Consequently, we found tRNA/mir-34a was effective in suppressing proliferation of A549, H460, HepG2, Huh-7, MCF7, MDA-MB-231, PANC-1, and AsPC-1 cells. The anti-cancer activity of polymer-formulated tRNA/mir-34a was further shown in nude mice bearing A549 xenografts. Our findings provide evidences that the recombinant tRNA/mir-34a has therapeutic activity in preclinical models and support a framework for development of tRNA/mir-34a–based treatment strategies in cancer patients.