Characterization of Total RNA, CD44, FASN, and PTEN mRNAs from Extracellular Vesicles as Biomarkers in Gastric Cancer Patients.

Philipp Rhode,Christoph Kahlert,Thomas Kurth,Florian Lordick,Irina Estrela-Lopis,Katrin Schierle,Tom Venus,Boris Jansen-Winkeln,Orestis Lyros,Matthias Mehdorn,Ines Gockel,René Thieme

doi:10.3390/cancers13235975

Abstract

Simple SummaryLiquid biopsy is an easily accessible and non-invasive method to gain information about tumor diseases. The purpose of our study was to determine the value of extracellular vesicle-derived mRNAs as biomarkers for the diagnosis of gastric cancer and the response to its treatment. In a cohort of 87 gastric cancer patients and a control group of 14 individuals, we analyzed the absolute RNA concentration from extracellular vesicles (EV) and the relative levels of FASN, PTEN, and CD44 mRNA, and their correlation with clinico-pathological features. These correlated with treatment, tumor grading, and the pathological subtype according to Laurén’s classification. This might reflect their potential as both diagnostic and therapeutic predictors.In-depth characterization has introduced new molecular subtypes of gastric cancer (GC). To identify these, new approaches and techniques are required. Liquid biopsies are trendsetting and provide an easy and feasible method to identify and to monitor GC patients. In a prospective cohort of 87 GC patients, extracellular vesicles (EVs) were isolated from 250 µL of plasma. The total RNA was isolated with TRIZOL. The total RNA amount and the relative mRNA levels of CD44, PTEN, and FASN were measured by qRT-PCR. The isolation of EVs and their contained mRNA was possible in all 87 samples investigated. The relative mRNA levels of PTEN were higher in patients already treated by chemotherapy than in chemo-naïve patients. In patients who had undergone neoadjuvant chemotherapy followed by gastrectomy, a decrease in the total RNA amount was observed after neoadjuvant chemotherapy and gastrectomy, while FASN and CD44 mRNA levels decreased only after gastrectomy. The amount of RNA and the relative mRNA levels of FASN and CD44 in EVs were affected more significantly by chemotherapy and gastrectomy than by chemotherapy alone. Therefore, they are a potential biomarker for monitoring treatment response. Future analyses are needed to identify GC-specific key RNAs in EVs, which could be used for the diagnosis of gastric cancer patients in order to determine their molecular subtype and to accompany the therapeutic response.

Highlights

Gastric cancer (GC) is the fifth most common cancer entity worldwide
The remaining 27 patients were recruited after their first diagnosis and had undergone various treatment algorithms, including chemotherapy and gastrectomy, in the past
We clearly showed the suitability of total RNA isolation from plasmaderived extracellular vesicles (EVs) in gastric cancer (GC) patients

Summary

Introduction

Gastric cancer (GC) is the fifth most common cancer entity worldwide. There are over 1 million new diagnosed cases and 748,000 GC-related death per year. Cancer-related mortality from GC is high [1]. While gastric cancer is diagnosed early due to available screening programs in Asia South Korea), diagnoses in western countries are mostly late with locally advanced tumor stages [2]. The incidence in Asian countries is much higher than in western populations [3]. In Europe, the standard of care for the treatment of locally advanced

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