MA02.02 A Novel 5-miR Signature Shows Promise as a Diagnostic Tool and as a Predictor of Cisplatin Response in NSCLC

Abstract

MicroRNAs are a class of small non-coding RNAs that range in size from 19-25 nucleotides. They have been shown to regulate a number of processes within tumor biology, including metastasis, invasion and angiogenesis. More recently, miRNAs have been linked to chemoresistance in solid tumors, including lung cancer. MicroRNA expression within an isogenic panel of age-matched parent (PT) and cisplatin resistant (CisR) NSCLC cell lines was profiled using the 7th generation miRCURY LNA arrays (Exiqon). Significantly altered miRNAs within the CisR sublines were manipulated using antagomirs (Exiqon) and Pre-miRs (Ambion) and functional studies were carried out in the presence and absence of cisplatin. To examine the translational relevance of these miRNAs, their expression was examined in a cohort of chemo-naïve patient-matched normal and lung tumor tissue and serum from NSCLC patients of different histologies. To create a xenograft model of cisplatin resistance 1x103 cells H460 PT or CisR cells were injected into 5-7week old NOD/SCID mice. Tumor volume was measured over time and harvested once the tumor mass measured 500mm3 and formalin-fixed and paraffin embedded (FFPE). Expression of the 5-miR signature was analysed within FFPE murine tumors and cisplatin resistance was investigated relative to cisplatin sensitive controls. Profiling and subsequent validation revealed a 5-miR signature associated with our model of cisplatin resistance (miR-30a-3p, miR-30b-5p, miR-30c-5p, miR-34a-5p, miR-4286). Inhibition of the miR-30 family and miR-34a-5p reduced clonogenic survival of CisR cells when treated cisplatin. Expression of the miRNA signature was significantly altered in both adenocarcinoma (AD) and squamous cell carcinoma (SCC) relative to matched normal lung tissue and between SCC and AD tissue. miR-4286 was significantly up-regulated in SCC sera compared to normal control and AD sera. Similarly to the cell line expression of the miRNAs, the miR-30 family members and miR-34a-5p were up-regulated in the CisR xenograft FFPE tissue relative to PT. A novel miRNA signature associated with cisplatin resistance was identified in vitro, genetic manipulation of which altered clonogenic response to cisplatin. The 5-miR signature shows both diagnostic and prognostic biomarker potential across a number of diagnostically relevant biological mediums.