Cyanine Phototruncation Enables Spatiotemporal Cell Labeling

• Published in: Journal of the American Chemical Society Vol. 144; no. 25; pp. 11075 - 11080
• Main Authors: Fukushima, Hiroshi, Matikonda, Siddharth S., Usama, Syed Muhammad, Furusawa, Aki, Kato, Takuya, Štacková, Lenka, Klán, Petr, Kobayashi, Hisataka, Schnermann, Martin J.
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 29.06.2022; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Multidisciplinary; Physical Sciences; Science & Technology; IDENTIFICATION; EGFP; LYMPH-NODE; IN-VIVO; TRACKING
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.2c02962

Photoconvertible tracking strategies assess the dynamic migration of cell populations. Here we develop phototruncation-assisted cell tracking (PACT) and apply it to evaluate the migration of immune cells into tumor-draining lymphatics. This method is enabled by a recently discovered cyanine photoconversion reaction that leads to the two-carbon truncation and consequent blue-shift of these commonly used probes. By examining substituent effects on the heptamethine cyanine chromophore, we find that introduction of a single methoxy group increases the yield of the phototruncation reaction in neutral buffer by almost 8-fold. When converted to a membrane-bound cell-tracking variant, this probe can be applied in a series of in vitro and in vivo experiments. These include quantitative, time-dependent measurements of the migration of immune cells from tumors to tumor-draining lymph nodes. Unlike previously reported cellular photoconversion approaches, this method does not require genetic engineering and uses near-infrared (NIR) wavelengths. Overall, PACT provides a straightforward approach to label cell populations with spatiotemporal control.