Abstract 4311: Fluorescence-guided surgery of pancreatic cancer using activatable cell penetrating peptides (ACPPs) in orthotopic mouse models

Abstract

Abstract Surgical resection with complete removal of tumor remains one of the most effective modalities in the treatment of cancer. The aim of this study was to evaluate the efficacy of using activatable cell penetrating peptides (ACPPs) conjugated to Cy5 fluorophores to accurately label primary pancreatic tumor for fluorescence-guided surgery (FGS) in orthotopic mouse models. Orthotopic mouse models of human pancreatic cancer using surgical implantation of tumor fragments of the MiaPaca-2-GFP pancreatic cancer cell line were established. Two weeks after tumor implantation, the tumors were resected with bright light surgery (BLS) or FGS. FGS was performed with a florescence-dissecting microscope (MVX10, Olympus) 2 hours after periorbital injection of ACPPs. Completeness of resection was assessed from postoperative images obtained with the Maestro CRI Small Imaging System. Postoperatively, we performed whole body imaging of the mice to assess for recurrence. At eight weeks, mice were sacrificed to evaluate pancreatic tumor burden, as well as local and distant recurrence. Cy-5-conjugated ACPPs, cleavable by MMP-2 and MMP-9 permitted clear visualization of tumor margins for fluorescence-guided resection. With FGS, no residual tumor was detected in the postoperative surgical site in all 16 mice. One mouse out of 16 undergoing BLS had evidence of residual tumor postoperatively. At 8 weeks, mice in the BLS group demonstrated larger primary tumors compared to mice in the FGS group (1.72 g ± SE 0.58 vs 0.25 g ± SE 0.14, p=0.026). Mean disease-free survival (DFS) was significantly lengthened from 5.33 weeks in the BLS group to 7.38 weeks in the FGS group (p=0.02). Furthermore, recurrence rates were lower in the FGS group (38% vs 73%, p=0.049). This translated into a lower local and distant recurrence rate for FGS (31% vs 67% and 25% vs 60%, respectively). ACPPs can provide an alternative method to accurately and effectively label cancer cells for improved resection of tumors that do not express specific tumor antigens and result in better outcomes post-resection. Citation Format: Cristina A. Metildi, Sharmeela Kaushal, Csilla N. Felsen, Quyen T. Nguyen, Robert M. Hoffman, Roger Y. Tsien, Michael Bouvet. Fluorescence-guided surgery of pancreatic cancer using activatable cell penetrating peptides (ACPPs) in orthotopic mouse models. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4311. doi:10.1158/1538-7445.AM2014-4311