Profiling of 179 miRNA Expression in Blood Plasma of Lung Cancer Patients and Cancer-Free Individuals.

Lung cancer is one of major cancers, and survival of lung cancer patients is dictated by the timely detection and diagnosis. Cell-free circulating miRNAs were proposed as candidate biomarkers for lung cancer. These RNAs are frequently deregulated in lung cancer and can persist in bodily fluids for extended periods of time, shielded from degradation by membrane vesicles and biopolymer complexes. To date, several groups reported the presence of lung tumour-specific subsets of miRNAs in blood. Here we describe the profiling of blood plasma miRNAs in lung cancer patients, healthy individuals and endobronchitis patients using miRCURY LNA miRNA qPCR Serum/Plasma Panel (Exiqon). From 241 ratios differently expressed between cancer patients and healthy individuals 19 miRNAs were selected for verification using the same platform. LASSO-penalized logistic regression model, including 10 miRNA ratios comprised of 14 individual miRNAs discriminated lung cancer patients from both control groups with AUC of 0.979.

Plasma miR-19b and miR-183 as Potential Biomarkers of Lung Cancer.

Lung cancer is a complex disease that often manifests at the point when treatment is not effective. Introduction of blood-based complementary diagnostics using molecular markers may enhance early detection of this disease and help reduce the burden of lung cancer. Here we evaluated the diagnostic potential of seven plasma miRNA biomarkers (miR-21, -19b, -126, -25, -205, -183, -125b) by quantitative reverse transcription PCR. Influence clinical and demographical characteristics, including age, tumor stage and cancer subtype on miRNA levels was investigated. Four miRNAs were significantly dysregulated (miR-19b, -21, -25, -183) in lung cancer patients. Combination of miR-19b and miR-183 provided detection of lung cancer with 94.7% sensitivity and 95.2% specificity (AUC = 0.990). Thus, miRNAs have shown the potential to discriminate histological subtypes of lung cancer and reliably distinguish lung cancer patients from healthy individuals.

Cell-Free miRNA-141 and miRNA-205 as Prostate Cancer Biomarkers.

Expression levels of five miRNAs (miR-19b, miR-21, miR-126, miR-141, miR-205) were measured in the plasma of healthy donors and prostate cancer patients. It was shown that miR-141 expression level efficiently discriminates early stage prostate cancer patients and correlates with the Gleason score.

Comparative Study of Extracellular Vesicles from the Urine of Healthy Individuals and Prostate Cancer Patients.

Recent studies suggest that extracellular vesicles may be the key to timely diagnosis and monitoring of genito-urological malignancies. In this study we investigated the composition and content of extracellular vesicles found in the urine of healthy donors and prostate cancer patients. Urine of 14 PCa patients and 20 healthy volunteers was clarified by low-speed centrifugation and total extracellular vesicles fraction was obtain by high-speed centrifugation. The exosome-enriched fraction was obtained by filtration of total extracellular vesicles through a 0.1 µm pore filter. Transmission electron microscopy showed that cell-free urine in both groups contained vesicles from 20 to 230 nm. Immunogold staining after ultrafiltration demonstrated that 95% and 90% of extracellular vesicles in healthy individuals and cancer patients, respectively, were exosomes. Protein, DNA and RNA concentrations as well as size distribution of extracellular vesicles in both fractions were analyzed. Only 75% of the total protein content of extracellular vesicles was associated with exosomes which amounted to 90-95% of all vesicles. Median DNA concentrations in total extracellular vesicles and exosome-enriched fractions were 18 pg/ml and 2.6 pg/ml urine, correspondingly. Urine extracellular vesicles carried a population of RNA molecules 25 nt to 200 nt in concentration of no more than 290 pg/ml of urine. Additionally, concentrations of miR-19b, miR-25, miR-125b, and miR-205 were quantified by qRT-PCR. MiRNAs were shown to be differently distributed between different fractions of extracellular vesicles. Detection of miR-19b versus miR-16 in total vesicles and exosome-enriched fractions achieved 100%/93% and 95%/79% specificity/sensitivity in distinguishing cancer patients from healthy individuals, respectively, demonstrating the diagnostic value of urine extracellular vesicles.

Dynamic changes in circulating miRNA levels in response to antitumor therapy of lung cancer.

PURPOSE: Expression levels of cancer-associated microRNAs were reported to be altered in serum/plasma samples from lung cancer patients compared with healthy subjects. The purpose of this study was to estimate the value of five selected miRNAs plasma levels as markers of response to antitumor therapy in lung cancer patients. MATERIALS AND METHODS: Expression levels of miR-19b, miR-126, miR-25, miR-205, and miR-125b have been evaluated by quantitative reverse transcription PCR versus control miR-16 in blood plasma samples from 23 lung cancer (LC) patients. Plasma samples were obtained from LC patients before treatment (untreated-UT), within 30 days after completing two courses of chemotherapy (postchemotherapy-PC) and 15 days after surgery (postoperative-PO). RESULTS: Repeated Measures ANOVA demonstrated that miR-19b expression levels were decreased in PC and increased in PO samples. These changes were characterized by a significant quadratic trend (p = 0.03). Expression levels of miR-125b increased both after chemotherapy and again after surgery and demonstrated a significant linear trend (p = 0.03). The miR-125b/miR-19b ratio changed during the course of the antitumor treatment with a significant linear trend (p = 0.04). Individual analysis in the groups of patients with partial response to chemotherapy and patients with stable or progressive disease showed different trends for miR-19b, miR-125b, and miR-125b/miR-19b ratio between the groups. The Kaplan-Meier survival curves demonstrated an association of miR-125b/miR-19b ratio value with the survival time without the tumor relapse (p < 0.1). CONCLUSIONS: Dynamic change of trends for miR-19b and miR-125b expression levels and miR-125b/miR-19b ratio in the blood plasma have shown a potentiality to discriminate types of response to antitumor therapy in lung cancer patients. Further in-depth investigation is needed to establish a direct link the miRNAs expression levels in blood plasma with therapy response and patient's survival.

Protocol for miRNA isolation from biofluids.

MicroRNAs (miRNAs) have been identified as promising biomarkers in cancer and other diseases. Packaging of miRNAs into vesicles and complexes with proteins ensures their stability in biological fluids but also complicates their isolation. Conventional protocols used to isolate cell-free RNA are generally successful in overcoming these difficulties; however, they are costly, labor-intensive, or heavily reliant on the use of hazardous chemicals. Here we describe a protocol that is suitable for isolating miRNAs from biofluids, including blood plasma and urine. The protocol is based on precipitation of proteins, denaturation of miRNA-containing complexes with octanoic acid and guanidine isothiocyanate, and subsequent purification of miRNA on spin columns. The efficacy of miRNA extraction by phenol-chloroform extraction, miRCURY RNA isolation kit--biofluids (Exiqon), and the proposed protocol was compared by quantitative reverse-transcription PCR of miR-16 and miR-126. The proposed protocol was slightly more effective for isolating miRNA from plasma and significantly superior to the other two methods for miRNA isolation from urine. Spectrophotometry and SDS-PAGE data suggest that the disparity in performance between miRCURY Biofluids and the proposed protocol can be attributed to differences in precipitation mechanisms, as confirmed by the retention of different proteins in the supernatant.