Abstract 3985: Dynamic changes of tumor-derived extracellular vesicles and related RNAs in blood samples of NSCLC patients
Authors: Lampignano Rita , Neumann Martin , Kloten Vera , Kessler Nina , Babayan Anna , Keller Laura , Stevic Ines , Pantel Klaus , Krahn Thomas , Schlange Thomas ,   for the IMI CANCER-ID consortium
Published: August 2019

Abstract
Liquid biopsy is defined as molecular analysis of rare cells or cell-free nucleic acids circulating in blood or in other biofluids. The concept of liquid biopsy aims at closely monitoring the status of a disease or treatment efficacy in a simple, fast, cost efficient way and at any point in time with minimal risk and burden for the patient. It has been suggested that the most reproducible approach to investigate “liquid” mRNAs would be to focus on cell-free extracellular vesicle (EV)-transcripts rather than on circulating cell-free mRNAs, as the former are well protected from degradation and therefore more stable. However, the volumes of available blood samples can be limiting for molecular analysis and rare cells as well as cell-free nucleic acids are normally present in low abundance. Therefore, detection of rare events or quantification of limited material requires robust, highly sensitive technologies like droplet digital PCR (ddPCR).
In this pilot study, we investigated the absolute expression of 10 EV-transcripts typically involved in cancer development and chemotherapy resistance in longitudinal serum samples of 13 non-small cell lung cancer (NSCLC) patients (age range 37-76 years) treated with cisplatin at the Department of Inner Medicine II, University of Ulm, between May 2011 and August 2012.
Blood samples were collected at baseline, after 3-6 months and after 9-12 months of chemotherapy from patients showing objective clinical response. Then, EV-RNAs were isolated by sequentially processing obtained serum samples with miRCURY® exosome kit and miRNeasy kit (both Qiagen, Hilden, Germany). Afterwards, the status of selected EV-transcripts was investigated via ddPCR (Biorad, Milan, Italy).
After start of chemotherapy, we observed a downregulation of at least 2-fold of the following potentially cancer-related EV-transcripts : PTEN, ERBB2, FOSL1, IL-8, MET, RPS27A, SF3B1 and of the following housekeeping EV-mRNAs: ACTB, HIST1H3H and HSPA1A, in all patients. Interestingly, in none of patients' samples, the expression of EV-AKT1 and of EV-PD-L1 transcripts could be detected.
Our preliminary results demonstrates significant dynamic changes of cancer-related EV-mRNA expression in serum samples of NSCLC patients during cisplatin treatment, thus suggesting a potential overall decrease of EVs in response to chemotherapy. Moreover, despite the small amounts of mRNA in extracellular vesicles from patient blood, using ddPCR differential mRNA levels could be determined in patient serum and expand the scope of biomarker analysis of EVs.
This work is supported by IMI JU & EFPIA (grand no. 115749, CANCER-ID). Samples from patients and healthy volunteers, respectively, were collected under signed informed consent.
Citation Format: Rita Lampignano, Martin Neumann, Vera Kloten, Nina Kessler, Anna Babayan, Laura Keller, Ines Stevic, Klaus Pantel, Thomas Krahn, Thomas Schlange, for the IMI CANCER-ID consortium. Dynamic changes of tumor-derived extracellular vesicles and related RNAs in blood samples of NSCLC patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3985.