New method: NanoString technology to detect protein expression in minimally invasive puncture samples

Due to its high sensitivity, high repeatability and no need for reverse transcription and amplification during the detection process, NanoString technology has received wide attention and recognition. Now this technology is widely used in the detection of gene expression (mRNA), small RNA (miRNA), copy number variation (CNV), long-chain non-coding RNA (lncRNA), but these detection targets are nucleic acids, for The expression of cellular proteins is still powerless. Recently, a research paper entitled "Cancer Cell Profiling by Barcoding Allows Multiplexed Protein Analysis in Fine-Needle Aspirates" was published in Science Translational Medicine magazine, which reported a kind of NanoString based on Adeeti V. Ullal and his colleagues. A new method of detecting protein expression in technology. The method utilizes the high sensitivity and reverse transcription characteristics of NanoString technology to accurately detect the expression of cell surface proteins in trace samples obtained by the method of Fine-needle aspirates (FNAs).

Under ideal conditions, clinical samples should be continuously taken at different stages of disease development to track changes in key proteins. However, this method of drawing is expensive and has a large damage. The minimally invasive puncture method allows continuous extraction, but the number of cells taken by this method is limited, limiting the amount of protein that can be analyzed. Although multiplexed flow cytometry and mass cytometry can be used to detect small numbers of cells. However, multiplexed flow cytometers have very limited markers that can be detected due to spectral overlap. However, mass spectrometry flow cell technology loses a lot of samples during sample preparation, so neither of these techniques is suitable for detecting proteome information from trace sample sources.

Adeeti V. Ullal and his colleagues design the ABCD detection platform (antibody barcoding with photocleavable DNA, ABCD). The platform uses a DNA-tagged antibody to detect cell surface proteins. This DNA tag is chemically stable and The photocleaved small molecule ligation fragment is attached to the antibody molecule such that each protein corresponds to a unique antibody, and each antibody corresponds to a unique DNA tag. We only need to detect the DNA tag to know the expression of the cell surface protein. Happening. After binding to the target cells, the excess unbound antibody is washed away, and the DNA tag is dissociated by a light pulse, and then the reporter probe and the capture probe provided by NanoString are used for detection, and the expression of the target cell protein can be obtained. . Other techniques, such as sequencing, qPCR, etc., can also be used for detection of this method, but sequencing and qPCR can produce errors caused by amplification bias, while NanoString technology does not require amplification. Very good reduced protein expression was therefore chosen by the Institute. They used this technique to detect breast cancer cell lines and clinical samples of lung cancer, and found that the heterogeneity of protein expression in the cell samples inside the same cancer and the heterogeneity of protein expression in different cases, indicating that the same cancer is internal and The individual cells vary greatly among different cases, so this technique can provide a basis for the prognosis prediction of tumor patients and individualized medical treatment of tumors.

Figure: Technical principle

A. Cell separation; B. DNA-tagged antibodies are incubated with cells; C. Light pulses dissociate DNA tags, and DNA tags are detected using reporter and capture probes to obtain protein expression.

Please refer to the original content for details: http://stm.sciencemag.org/content/6/219/219ra9.short