Clinical Significance of let-7a-5p and miR-21-5p in Patients with Breast Cancer.

OBJECTIVE: To investigate the clinical significance of serum let-7a-5p and miR-21-5p in the diagnosis of breast cancer. METHODS: We examined 32 healthy people and 30 patients with benign breast lesions as controls and 90 breast cancer patients as study subjects. The expression of let-7a-5p and miR-21-5p were detected in all subjects' samples, and Cel-miR-39-3p was used as a spike-in reference. Serum miRNAs were extracted by the TRIzol method, and reverse transcription was performed with specific primers for let-7a-5p, miR-21-5p and Cel-miR-39-3p, and 2-µL reverse transcription products were used as PCR templates. A SLAN-96P fluorescent quantitative PCR instrument was used for quantitative PCR detection. RESULTS: (1) The serum levels of carcinoembryonic antigen (CEA)and carbohydrate antigen 15-3 (CA15-3) in the breast cancer group were higher than those in the healthy controls and patients with benign breast lesions; (2) The expression level of let-7a-5p in the serum of the breast cancer group was lower than that in the healthy control group (P<0.05), but there was no significant difference compared to the breast benign lesion group (P>0.05); (3) The serum expression level of miR-21-5p in the breast cancer group was lower than that in the healthy control group (P<0.05) but was not significantly different from that in the patients with benign breast lesions (P>0.05). CONCLUSION: Reduced expression of Let-7a-5p and miR-21-5p levels is of little value for early diagnosis of breast cancer; however reduced expression of Let-7a-5p and miRNA-21-5p may serve as non-invasive biomarkers for the diagnosis of breast cancer metastasis, and combination of these markers with CEA and CA15-3 can help to distinguish benign breast lesions from breast cancer.

Heparinase treatment of heparin-contaminated plasma from coronary artery bypass grafting patients enables reliable quantification of microRNAs.

BACKGROUND: microRNAs have recently been identified as powerful biomarkers of human disease. Reliable polymerase chain reaction (PCR)-based quantification of nucleic acids in clinical samples contaminated with polymerase inhibitor heparin requires deheparinization. However, the effects of deheparinization procedure on quantification of nucleic acids remain largely unknown. The aim of this study was to determine whether the deheparinization procedure completely eliminates the inhibition of amplification, while maintaining RNA integrity and technical variability of the measured microRNA levels. METHODS: Heparinized plasma from 9 patients undergoing coronary artery bypass grafting (CABG) and the heparin-free plasma from 58 rats were spiked with a synthetic RNA oligonucleotide and total RNA was extracted. The RNA solutions were then treated with heparinase I to remove contaminating heparin prior to reverse transcription. Levels of synthetic spike-in RNA oligonucleotide, as well as endogenous hsa-miR-1-3p and hsa-miR-208a-3p, were measured using quantitative reverse transcription PCR (RT-qPCR). The amplification efficiency and presence of inhibitors in individual samples were directly determined using calibration curves. RESULTS: In contrast to RNA samples from rat plasma, RNA samples derived from the CABG patient plasma contained inhibitors, which were completely eliminated by treatment with heparinase. The procedure caused a decrease in the amount of detected RNA; however, the technical variability of the measured targets did not change, allowing for the quantification of circulating endogenous hsa-miR-1-3p and hsa-miR-208a-3p in the plasma of CABG patients. CONCLUSIONS: The heparinase treatment procedure enables utilization of RT-qPCR for reliable microRNA quantification in heparinized plasma.

MicroRNA profiles in graft preservation solution are predictive of ischemic-type biliary lesions after liver transplantation.

BACKGROUND & AIMS: Ischemic-type biliary lesions (ITBL) are the second most common cause of graft loss after liver transplantation. Though the exact pathophysiology of ITBL is unknown, bile duct injury during graft preservation is considered to be a major cause. Here we investigated whether the release of cholangiocyte-derived microRNAs (CDmiRs) during graft preservation is predictive of the development of ITBL after liver transplantation. METHODS: Graft preservation solutions (perfusates) and paired liver biopsies collected at the end of cold ischemia were analysed by RT-qPCR for CDmiR-30e, CDmiR-222, and CDmiR-296 and hepatocyte-derived miRNAs (HDmiRs) HDmiR-122 and HDmiR-148a. MicroRNAs in perfusates were evaluated on their stability by incubation and fractionation experiments. MicroRNA profiles in perfusates from grafts that developed ITBL (n=20) and grafts without biliary strictures (n=37) were compared. RESULTS: MicroRNAs in perfusates were proven to be stable and protected against degradation by interacting proteins. Ratios between HDmiRs/CDmiRs were significantly higher in perfusates obtained from grafts that developed ITBL (p<0.01) and were identified as an independent risk factor by multivariate analysis (p<0.01, HR: 6.89). The discriminative power of HDmiRs/CDmiRs in perfusates was validated by analysis of separate brain death- (DBD) and cardiac death donors (DBD; p ≤ 0.016) and was superior to expression in liver biopsies (C=0.77 in perfusates vs. C<0.50 in biopsies). CONCLUSIONS: This study demonstrates that differential release of CDmiRs during graft preservation is predictive of the development of ITBL after liver transplantation. This provides new evidence for the link between graft-related bile duct injury and the risk for later development of ITBL.