Abstract 2471: Targeted dendrimer nanocarrier delivery of bioluminescent proteins for pancreatic cancer detection

Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer and has a very low survival rate. This cancer often does not show symptoms until more advanced stages, leading to late-stage diagnosis in up to 80% of cases. Molecular tools for accurate identification of the cancer cells can lead to a timely diagnosis. Currently, blood antigen testing with CA 19-9 and tumor imaging using ultrasound, CT, and MRI are the standards for identification. However, these methods are limited in their ability to discern key attributes such as tumor localization, grading, and metastasis. To overcome this, we can utilize selective recognition of PDAC markers to deliver a bioluminescent protein for targeted imaging. We applied dendrimers as a nanocarrier that can hold both the PDAC-targeting protein and the bioluminescent protein for enhancement of blood-circulation and tumor-retention time, thereby producing a stronger, longer lasting luminescent signal. This cell-specific recognition assembly can locate both localized and metastatic PDAC cells, enabling an accurate diagnosis, localization of tumor margin, and identification of metastases using bioluminescence-based imaging. The targeted construct was formed by fusing an EGFR-specific affibody to Gaussia luciferase, a bioluminescent protein, and binding that to a G5 polyamidoamine dendrimer nanocarrier. Western Blotting and confocal microscopy using PANC 10.05 cells confirmed the expression of EGFR and enhanced uptake of the targeted construct in vitro. For in vivo studies, female NSG mice were used as a xenograft model with PANC 10.05 cells with either subcutaneous, renal capsule, or orthotopic tumors. Tumor-bearing mice were treated with dendrimer-fusion protein constructs and imaged using IVIS. Controls included non-targeted bioluminescent proteins and non-tumor-bearing mice. The presence of EGFR on the tumors of implanted mice was confirmed using Western blotting and histological staining. We showed that the EGFR-targeted construct was capable of facilitating selective uptake into the tumors in all three mouse models, demonstrating that the cell-specific construct could localize to the PDAC cells and emit bioluminescence when imaged with IVIS. Accuracy of the tumor localization was also confirmed with ultrasound. Additionally, we demonstrated the ability of the construct to locate metastases using both live-animal imaging and ex vivo organ analysis. These bioluminescent nanocarriers are capable o