br Conclusion br In conclusion a sensitive
In conclusion, a sensitive assay combining DPD probe and mass spectrometry has been exploited for miRNA detection in this study. Using a self-designed and self-prepared DPD probe, the target miRNA signal was amplified by the peptide branches of the probe and ultimately converted to the mass response of reporter peptide. The signal intensity of the target miRNA was enhanced by approximately 8 fold compared to that without signal
Correlation of miR-21 Remdesivir level with the histopathological parameters and molecular subtypes of 102 breast tumors. P value of less than 0.05 was considered sta-tistically significant and data were analyzed by Kruskal-Wallis test or Mann-Whitney test using SPSS v19.0.
Cases miR-21 expression level in breast tumors (copies/mg) p
Fig. 7. Kaplan-Meier survival curves and log-rank test. (A) Kaplan-Meier curve for 5-year overall survival rates (63.7%) of 102 breast cancer patients. (B) Kaplan-Meier curves and log-rank test of breast cancer patient groups classified as showing either high (n ¼ 51) or low (n ¼ 51) miR-21 expression, which were divided by the median level of miR-21. miR-21 expression had a significant relationship with patient survival (log-rank, p < 0.001).
amplification. In addition, mass spectrometry facilitated the quantification in a more accurate manner. These features can pro-vide extra value for miRNA quantification, especially for the quantitative analysis of low-abundant miRNAs. For example, some miRNAs were down-regulated in breast cancer, such as miR-125b and miR-9-1 . Using our assay, these miRNAs can be easily quantified by replacing the current DNA sequence with the one that is complementary to the desired miRNA, while keeping other parts of the DPD probe the same. However, characterization including hybridization and digestion, deserves further evaluation. Finally, the amplification capability of the assay should be further enhanced with the increase of dendrimer generation level, how-ever, more factors including synthesis, purification and conjugation need careful consideration in future studies.
This study was approved by the Institutional Review Board of Nanjing Medical University, Nanjing, China.
Declaration of interests
The authors declare that they have no known competing
financialinterestsor personal relationships that could have appeared to influence the work reported in this paper.
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests.
The National Natural Science Fund (21722504, 21675089, 21175071), the SEU-NJMU cooperation project (2242017K3DN12), the Primary Research and Development Plan of Jiangsu Province (BE2018725) and the Open Foundation of State Key Laboratory of Reproductive Medicine [SKLRM-GA201804] awarded to Dr. Chen are gratefully acknowledged. The technical support from Dr. Danni Li at Department of Lab Medicine and Pathology, University of Minnesota is also kindly acknowledged.
Appendix A. Supplementary data
 D.P. Bartel, MicroRNAs: target recognition and regulatory functions, Cell 136
 P. PospıSil, J. Skotnica, J. Naus, Low and high temperature dependence of
minimum f and maximum f m chlorophyll fluorescence in vivo, Biochim.
Laere, Dysregulation of microRNAs in breast cancer and their potential role as
 F. Xu, T. Yang, Y. Chen, Quantification of microrna by DNA-peptide probe and
prognostic and predictive biomarkers in patient management, Breast Cancer
liquid chromatography-tandem mass spectrometry-based quasi-targeted
 G. Bertoli, C. Cava, I. Castiglioni, MicroRNAs: new biomarkers for diagnosis,
 J.K. Steehler, Introduction to mass spectrometry: instrumentation, applica-
prognosis, therapy prediction and therapeutic tools for breast cancer, Thera-
probes and liquid chromatography-tandem mass spectrometry (LC-MS/MS): a
quasi-targeted proteomics approach for multiplexed microrna quantification,
 K. Sadler, J.P. Tam, Peptide dendrimers: applications and synthesis,
centrations and integrity in serum of initial and treated of lymphoma patients,
Social Science Research on Health and Aging: A Review of Theory and Practice,
 J.P. Tam, 12-synthesis and applications of branched peptides in immunolog-
Biosocial Surveys, Part I-8, The National Academies Press, Washington DC,
 E. Varallyay, J. Burgyan, Z. Havelda, MicroRNA detection by northern blotting
 J. Wan, P.F. Alewood, Peptide-decorated dendrimers and their bioapplications,
teomics approach for mirna quantification via a covalently immobilized DNA-