Letrozole‐Based Near‐Infrared Dynamic Imaging Targeting Ductal‐Vascular RhoJ From Pancreatic Intraepithelial Neoplasia to Pancreatic Ductal Adenocarcinoma

Abstract Pancreatic ductal adenocarcinoma (PDAC) relies heavily on neoangiogenesis for its progression, making early detection crucial. Here, LTZi‐MHI148 (Letrozole inhibitor bonding with MHI‐148 dye), a near‐infrared (NIR) fluorescent agent is developed, to target RhoJ (Ras Homolog Family Member J), a protein expressed in neonatal vasculature, for both imaging and therapy of early PDAC. This agent is synthesized by conjugating Letrozole with MHI‐148, exhibiting excellent NIR characteristics and photostability. In vitro studies showed that LTZi‐MHI148 selectively accumulated within pancreatic cancer cells through Organic Anion Transporting Polypeptide (OATP) transporters and bound to cytoplasmic RhoJ. In vivo, the probe effectively targeted neoangiogenesis and Pancreatic Intraepithelial Neoplasias (PanINs) in various PDAC models, including the orthotopic, ectopic, spontaneous, and tamoxifen‐induced tumors. Notably, LTZi‐MHI148 detected preneoplastic PanIN lesions with Overexpressed RhoJ and active neoangiogenesis in both spontaneous and tamoxifen‐induced PDAC murine models. Longitudinal imaging studies revealed that RhoJ‐targeted neoangiogenesis tracks lesion progression, highlighting LTZi‐MHI148's utility in monitoring disease progression. Furthermore, multiple LTZi‐MHI148 administrations attenuated PanINs to PDAC progression, suggesting its potential as a therapeutic intervention. These findings underscore the translational potential of LTZi‐MHI148 for the early detection and targeted therapy of PDAC, utilizing NIR‐I/II imaging to monitor RhoJ overexpression in precancerous ductal neoplasia associated with neoangiogenesis.