Abstract 4977: MIR1307 mediates pancreatic cancer resistance to FOLFIRINOX chemotherapy by affecting response to DNA damage
Authors: Carotenuto Pietro , Zito Domenico , Previdi Maria C. , Raj Maya , Fassan Matteo , Lampis Andrea , Scalafani Francesco , Lanese Andrea , Said-Huntingford Ian , Hahne Jens C. , Young Kate , Begum Ruwaida , Ethiar Zakaria , Wotherspoon Andrew , Starling Naureen , Sadanandam Anguraj , Cunningham David , Chau Ian , Workman Paul , Chopra Rajesh , Valeri Nicola , Braconi Chiara 
Published: August 2018

ntroduction: FOLFIRINOX-regime is a combination-chemotherapy that provides the best clinical benefit in pancreatic cancer (PC) patients, but is associated with severe toxicity. Aim of this study is to explore the role of miRNAs (MIR) as modulators of chemosensitivity and their potential as biomarkers of sensitivity to FOLFIRINOX-chemotherapy. Methods: High-throughput-screening (HTS) of 997 LNA-MIR-inhibitors was performed in PC cell lines (Capan1, MiaPaCa2) treated with a combination of Fluorouracil (F), Oxaliplatin (O) and Irinotecan (I) that mimics FOLFIRINOX-regime. Cell viability was monitored by CellTiter-Blue assay. Validation experiments were carried out with miRvana probes. MIR expression was assessed by TaqMan-assay. Apoptosis was measured by Flow-cytometry and western-blotting. Knock-out of microRNA was acheived by CRISPR-CAS9 in MiaPaca2 cells (MIR1307KO). Results: 41 and 84 miRNA-inhibitors enhanced FOI activity by &gt;30% (p&lt;0.001) in Capan1 and MiaPaCa2. These included MIR1307-inhibitor that was validated in Capan1, MiaPaCa2, Panc1, AspC1, BxPC3, and Su86.86 cell lines. The proportion of cells killed by FOI in comparison to DMSO was greater in cells transfected with MIR1307 inhibitor when compared to NEG CTRL, making the effect of this MIR specific for chemotherapy. MIR1307 was over-expressed in tumour compared to matched-adjacent tissue in 40/60 human PC cases, confirming clinical relevance. MIR1307KO cells were more sensitive to FOI than WT cells. Chemotherapy-induced apoptosis was higher in MIR1307KO cells (caspase 3/7 activity and annexin-V positivity). We observed significant upregulation of different markers of DNA damage (pH2AX2, 8OHdG, DNA breaks in Comet assay) in MIR1307KO cells treated with FOI in comparison to WT treated cells. Re-expression of MIR1307 in MIR1307KO cells could increase resistance to FOI chemotherapy and protected from FOI-induced DNA damage. Bioinformatics analysis identified MIR1307 binding-sites within a number of genes involved in the DNA-repair pathway (p&lt;0.001, folding energy value greater than -12 Kcal/mol). Conclusions: We identified miR-1307 as a potential modulator of sensitivity to FOI-chemotherapy in PC. We showed that miR-1307 inhibition impairs the ability of PC cells to recover from chemotherapy damage and therefore enhances its activity. The assessemnt of it potential as predictive biomarker of response in PC patients is ongoing.

Citation Format: Pietro Carotenuto, Domenico Zito, Maria C. Previdi, Maya Raj, Matteo Fassan, Andrea Lampis, Francesco Scalafani, Andrea Lanese, Ian Said-Huntingford, Jens C. Hahne, Kate Young, Ruwaida Begum, Zakaria Ethiar, Andrew Wotherspoon, Naureen Starling, Anguraj Sadanandam, David Cunningham, Ian Chau, Paul Workman, Rajesh Chopra, Nicola Valeri, Chiara Braconi. MIR1307 mediates pancreatic cancer resistance to FOLFIRINOX chemotherapy by affecting response to DNA damage [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4977.