Superresolution Fluorescence Microscopy of Platelet Subcellular Structures as a Potential Tumor Liquid Biopsy

Abstract

Blood‐based tumor liquid biopsies are promising as an alternative or complement to tissue biopsies due to their noninvasiveness, convenience, and safety, and there is still a great demand for the discovery of new biomarkers for these biopsies. Here, nanoscale distribution patterns of subcellular structures in platelets, as imaged by structured illumination superresolution fluorescence microscopy, as a new type of potential biomarker for tumor liquid biopsies are presented. A standardized protocol for platelet sample preparation and developed an automated high‐throughput image analysis workflow is established. The diagnostic capability based on the statistical analysis of 280 000 superresolution images of individual platelets from a variety of tumor patients, benign mass patients, and healthy volunteers (n = 206) is explored. These results suggest that the nanoscale distribution patterns of α‐granules in platelets have the potential to be biomarkers for several cancers, including glioma and cervical, endometrial, and ovarian cancers, facilitating not only diagnosis but also therapeutic monitoring. This study provides a promising novel type of platelet parameter for tumor liquid biopsies at the subcellular level rather than the existing cellular or molecular level and opens up a new avenue for clinical applications of superresolution imaging techniques.

Nanoscale insights into hematology: super-resolved imaging on blood cell structure, function, and pathology

“…In terms of clinical applications, the integration of nanoscopy with AI-based image analysis, as demonstrated by Zhang et al [ 83 ] for platelet analysis in cancer patients, holds great promise for automated, high-throughput diagnostic platforms. The development of nanoscopy-based liquid biopsy techniques, where circulating tumor cells or platelets are isolated from patient blood samples and analyzed for nanoscale protein distribution patterns, could enable minimally invasive early cancer detection and treatment monitoring.…”

“…D Representative confocal (1st line) and four-colored STED (2nd line) images of proteins in platelet, including Alexa594-phalloidin labelled actin in red, Alexa594-ab labelled fibrinogen in blue, ATTO647N-ab labelled PF-4 in green, and Dylight650-ab labelled VEGF [ 43 ]. E Representative comparison joint images of wide-field (WF) and SIM of anti-human von willebrand factor fused VWF proteins on α-granules in tumor patient’s platelet [ 83 ]. F Representative STED images of resting and ADP-activated platelet in left and right, anti-Erp29 labelled Erp29 in green and anti-VEGF labelled VEGF in red (1st line); anti- fibrinogen labelled fibrinogen, FNG (2nd line); anti-P-selectin labelled P-selectin (3rd line) [ 84 ].…”

“…Recent studies have revealed distinctive nanoscale alterations in the distribution and organization of platelet proteins in cancer patients compared to healthy individuals. Zhang et al [ 83 ] utilized SIM to identify circular coiling patterns of α-granules and microtubules in platelets from patients with glioma, cervical, endometrial, and ovarian cancers (Fig. 3 E).…”

Emerging Role of Tumor-Educated Platelets as a New Liquid Biopsy Tool for Colorectal Cancer

“…Imaging of platelet subcellular structures with super-resolution fluorescence microscopy is another advanced technology in the field of liquid biopsy that may open new horizons for clinical applications. 86 …”