Detection of Marker miRNAs, Associated with Prostate Cancer, in Plasma Using SOI-NW Biosensor in Direct and Inversion Modes.

Information about the characteristics of measuring chips according to their storage conditions is of great importance for clinical diagnosis. In our present work, we have studied the capability of chips to detect nanowire biosensors when they are either freshly prepared or have been stored for either one or two years in a clean room. Potential to detect DNA oligonucleotides (oDNAs)-synthetic analogues of microRNAs (miRNAs) 198 and 429 that are associated with the development of prostate cancer (PCa)-in buffer solution was demonstrated using a nanowire biosensor based on silicon-on-insulator structures (SOI-NW biosensor). To provide biospecific detection, nanowire surfaces were sensitized with oligonucleotide probes (oDNA probes) complimentary to the known sequences of miRNA 183 and 484. In this study it is demonstrated that freshly prepared SOI-NW biosensor chips with n-type conductance and immobilized oDNA probes exhibit responses to the addition of complimentary oDNAs in buffer, leading to decreases in chips' conductance at a concentration of 3.3 × 10-16 M. The influence of storage time on the characteristics of SOI-NW biosensor chips is also studied herein. It is shown that a two-year storage of the chips leads to significant changes in their characteristics, resulting in "inverse" sensitivity toward negatively charged oDNA probes (i.e., through an increase in chips' conductance). It is concluded that the surface layer makes the main contribution to conductance of the biosensor chip. Our results indicate that the detection of target nucleic acid molecules can be carried out with high sensitivity using sensor chips after long-term storage, but that changes in their surface properties, which lead to inversed detection signals, must be taken into account. Examples of the applications of such chips for the detection of cancer-associated microRNAs in plasma samples of patients with diagnosed prostate cancer are given. The results obtained herein are useful for the development of highly sensitive nanowire-based diagnostic systems for the revelation of (prostate) cancer-associated microRNAs in human plasma.

miRNAs expression signature potentially associated with lymphatic dissemination in locally advanced prostate cancer.

BACKGROUND: Prostate cancer is one of the most common and socially significant cancers among men. The aim of our study was to reveal changes in miRNA expression profiles associated with lymphatic dissemination in prostate cancer and to identify the most prominent miRNAs as potential prognostic markers for future studies. METHODS: High-throughput miRNA sequencing was performed for 44 prostate cancer specimens taken from Russian patients, with and without lymphatic dissemination (N1 - 20 samples; N0 - 24 samples). RESULTS: We found at least 18 microRNAs with differential expression between N0 and N1 sample groups: miR-182-5p, miR-183-5p, miR-96-5p, miR-25-3p, miR-93-5p, miR-7-5p, miR-615-3p, miR-10b, miR-1248 (N1-miRs; elevated expression in N1 cohort; p < 0.05); miR-1271-5p, miR-184, miR-222-3p, miR-221-5p, miR-221-3p, miR-455-3p, miR-143-5p, miR-181c-3p and miR-455-5p (N0-miRs; elevated expression in N0; p < 0.05). The expression levels of N1-miRs were highly correlated between each other (the same is applied for N0-miRs) and the expression levels of N0-miRs and N1-miRs were anti-correlated. The tumor samples can be divided into two groups depending on the expression ratio between N0-miRs and N1-miRs. CONCLUSIONS: We found the miRNA expression signature associated with lymphatic dissemination, in particular on the Russian patient cohort. Many of these miRNAs are well-known players in either oncogenic transformation or tumor suppression. Further experimental studies with extended sampling are required to validate these results.