Abstract 4424: Cancer stem cells-related microRNAs have prognostic implications in non-small cell lung cancer
Authors: Sandra Gallach Garcia, Alejandro Herreros-Pomares, Silvia Calabuig-Fariñas, Eva Escorihuela, Atilio Navarro, Aminta Isabel Martínez, Alberto Jacobo Cunquero, Eloisa Jantus-Lewintre, Carlos Camps
Journal: Cancer Research (2017)

Abstract Background: Lung cancer stem cells (CSCs) are a small population of stem-like cells that remains largely unknown. MicroRNAs (miRNAs) regulation of CSCs gene expression has been reported, constituting a promising therapeutic target. The aim of this study was to isolate and analyze differential expression of a set of miRNAs in tumorspheres from lung cancer cell lines and tumor tissue from resectable non-small cell lung cancer (NSCLC) patients and to determine the prognostic implications of these miRNAs in a cohort of resected-NSCLC patients. Methods: Lung CSC-related miRNAs (miR-145-5p, miR-188-5p, miR-218-5p, miR-34a-5p, miR-21-5p and miR-125a-5p) were analyzed in cells from seven NSCLC tumor samples and six cell lines (H1650, H1993, H480, H358, A549 and PC9) grown in monolayer and as spheroids by RTqPCR using TaqMan® microRNA assays. The expression levels of these six miRNAs were also analyzed in paired fresh-frozen tumor and normal adjacent lung tissue samples (N=178) from resected-NSCLC patients. Statistical analyses were considered significant at p&amp;lt;0.05. Results: miRNA expression analysis of cultured cells revealed an increased expression of miR-125a (p=0.04) and miR-188 (p=0.05) in lung tumorspheres from tumor samples and cell lines compared to their paired-adherent cells. Moreover, lungspheres from patients showed elevated expression levels of miR-21 when compared with their paired monolayer-cell cultures (p= 0.028). Interestingly, miR-125a, miR-188 and miR-21 had prognostic value when were analyzed in patients’ tissue samples. We found that those patients with higher levels (above the median) of miR-188 and miR-21 had a significant reduction in relapse-free survival (RFS, 23.67 vs 66.97 months; p= 0.009 and 24.03 vs 56.83 months, p= 0.042, respectively) and overall survival (OS, 42.9 vs NR months; p= 0.002 and 42.6 vs 82.60 months; p= 0.043, respectively), whereas the group of patients with higher levels of miR-125a had a worse outcome (OS 51.90 vs NR; p= 0.014). A signature combining the expression of miR-188 and miR-21 was able to give more significant prognostic information (RFS, 16.97 vs. 56.83 months; p= 0.006 and OS, 29.90 vs. NR; p&amp;lt;0.0001). The multivariate analysis including clinico-pathological and analytical variables revealed this miRNAs signature as an independent prognostic biomarker for RFS (HR 2.170 [1.372-3.431]; p= 0.001) and OS (HR 3.256 [1.907-5.561]; p&amp;lt;0.0001). Conclusions: Lung tumorspheres had increased levels of the CSC-related miRNAs miR-125a, miR-188 and miR-21, highlighting their role in the CSC biology. The analyses performed in a large cohort of resectable NSCLC patients show that a two miRNAs-signature (miR-188 and miR-21) was an independent prognostic marker for RFS and OS. Supported by grants RD06/0020/1024 and RD12/0036/0025 from RTICC-FEDER, PI12-02838 and PI15-00753 from ISCIII, TRACE (TRA09-0132) and Beca Roche Oncohematología. Note: This abstract was not presented at the meeting. Citation Format: Sandra Gallach Garcia, Alejandro Herreros-Pomares, Silvia Calabuig-Fariñas, Eva Escorihuela, Atilio Navarro, Aminta Isabel Martínez, Alberto Jacobo Cunquero, Eloisa Jantus-Lewintre, Carlos Camps. Cancer stem cells-related microRNAs have prognostic implications in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4424. doi:10.1158/1538-7445.AM2017-4424