MicroRNAs (miRNAs) are a class of small non-coding RNAs recently discovered as negative gene regulators. A large faction of miRNAs are located within the fragile regions of chromosomes, which are areas of the genome more tightly associated with human cancers, indicating the possible role of miRNAs in tumor development. It has been shown that miRNA expression profiles correlate with various cancers and the miRNA signatures are potentially unique cancer biomarkers to accurately diagnose and classify human cancers. However, human cancers are highly heterogeneous due in part to the high degree of intratumoral heterogeneity at the single-cell level, requiring the evaluation of a large number of single tumor cells, each of which the miRNA expression profile can be measured. Here we propose to combine a single-cell barcode chip platform and a novel ligation-based miRNA detection scheme to develop an innovative technology that for the first time offers both high-throughput and multiplexing for rapid miRNA detection in single cells without amplification and at low cost. More specifically, we will: (1) Design and validate a DNA barcode microarray for multiplexed detection of miRNA biomarkers without amplification, and (2) Integrate this barcode array with a nanoliter microfluidics chip to perform multiplexed detection of 12 miRNA biomarkers from a large number of single cancer cells. Our technology is a versatile platform to detect miRNA biomarkers implicated in a variety of human cancers. It can be further modified to detect other non-encoding RNAs and messenger RNA biomarkers from single cells. Moreover, the proposed microchip is inexpensive, scalable and easy to manufacture. It may find immediate applications in basic research and clinical stratification of human cancers.
The goal of this R21 application is i) to develop a single-cell microfluidic chip integrated with a high-density DNA barcode array to enable high throughput, multiplexed detection of microRNAs from single cells, and ii) to demonstrate the feasibility of detecting a panel of microRNA biomarkers from single cancer cells to assess cellular heterogeneity. The proposed project is designed to address the critical need for a practical tool to conduct informative miRNA profiling in both fundamental study of tumor heterogeneity and clinical diagnosis of human cancers and thus has significant impact in public health via providing a new tool for cancer diagnosis and stratification.