Figure 5. Longitudinal imaging of PanINs and pancreatic ductal adenocarcinomas (PDACs) in live mice indicate Dclk1⁺ PDAC cells supply progeny PDAC cells.

(A) Photo of an abdominal imaging window (AIW) composed of a custom-made magnet ring and 12 mm cover glass. (B) Scheme of the microscopic observation of the pancreas through an AIW. CA: cyanoacrylate. (C) Layout of the system for mouse live pancreas imaging. (D) Macroscopic images of pancreas with a nodule (arrowhead) transferred on the peritoneum (left) and observed through AIW (right). (E) Protocol of live imaging of PanINs formed in DRKF mice. The mice were treated with caerulein to accelerate PanIN formation. (F and G) Live imaging of PanINs formed in DRKF mice. (F) On the day of AIW installation, the following day of the final tamoxifen injection (day 3), several EGFP⁺ cells were observed through AIW (green) among Tomato-expressed tumor cells (magenta). (G) Ten days after AIW installation (day 13), almost all PanIN cells expressed EGFP in the same PanIN lesions of the same live DRKF mouse. Scale bar, 50 µm. (H) Protocol of live imaging of PDACs formed in DRKPF mice. (I and J) Live imaging of PDACs formed in DRKPF mice. (I) On the day of AIW installation, the following day of the final tamoxifen injection (day 0), EGFP⁺ PDAC cells were scarcely observed (green). (J) Seven days after tamoxifen injection, numerous PDAC cells were EGFP⁺ in the same live mouse (green). Scale bars, 50 µm. (K) Representative images of H and E staining and immunofluorescence staining for GFP, Krt19, and Hoechst of PDAC after live imaging. Scale bar, 50 µm.