Abstract PO-066: High uptake, retention, and in vivo activity of L-Annamycin in pancreatic cancer models

Abstract

Abstract Introduction: Annamycin (ANN) is a non-cardiotoxic potent topoisomerase II poison that is structurally related to doxorubicin (Dox) but it displays significantly different biological properties. ANN is formulated in multilamellar liposomes to enable effective in vivo administration as L-ANN. Pancreatic ductal adenocarcinoma (PDAC) represents a major challenge and is the deadliest cancer in decades. Pancreas drug uptake and retention remains a significant factor contributing to the chemoresistance of PDAC. Additionally, drug resistance on a cellular level further limits the therapeutic options for pancreatic cancer patients. Based on unique biological properties, we select L-ANN for detailed characterization of anti-tumor potency in preclinical PDAC models. Objective: The objective of this study was to validate the L-ANN exceptional uptake in pancreatic cancer cells and tumors and explore its high pancreas uptake to target PDACs by assessing the efficacy of L-ANN in the preclinical mouse models. Methods: The uptake, cytotoxicity, and L-ANN-induced apoptosis were studied in human MDA-PATC50 and MDA-PATC53 cell lines. L-ANN pharmacokinetics and tissue-organ distribution were analyzed in CD-1 mice after bolus administration of L-ANN, ANN or DOX. Subcutaneous and orthotopic MDA-PATC50 and MDA-PATC53 mouse models were used to assess activity of L-ANN in vivo. Results: Fluorescent microscopy and FACS analysis showed significantly higher uptake of ANN in MDA-PATC50 and MDA-PATC53 when compared to DOX-treated cells. Interestingly, ANN displayed distinct subcellular distribution with predominantly cytosolic localization. Average IC50 of ANN or DOX treated MDA-PATC50 and MDA-PATC53 cells were 25.1 nM and 41.9 nM for ANN and 32.8 nM and 130.4 nM for DOX respectively (72h exposure). Biodistribution study showed rapid L-Ann absorption in the pancreas. The Cmax of L-Ann was 15-fold higher than Dox after administration of L-ANN or Dox (both at 4 mg/kg) in pancreatic tissue. The subcutaneous models demonstrated dose-dependent reduction in tumor volumes after 3 doses of L-Ann in both PDAC models. Additionally, efficacy of L-ANN was assessed in two orthotopic PDAC models. MRI confirmed tumor volume reduction in L-Ann 3 mg/kg and 4 mg/kg doses in MDA-PATC50 model (p<0.05 for both 3 and 4 mg), and in MDA-PATC53 model (p<0.001 and p<0.0001, respectively). The median survivals (MS) were 135 and 103 days for L-Ann at 3 mg/kg and 4 mg/kg respectively (MS for vehicle was 49 days, p<0.0001). MDA-PATC50 orthotopic model demonstrated the similar results (ongoing study). Conclusion: Annamycin exhibits high and rapid uptake in the pancreatic cancer cells and in pancreas itself when compared to Dox. Subsequently, ANN appeared to be highly cytotoxic against tested pancreatic cancer cell lines and as L-ANN potently inhibits tumor growth and increase survival in experimental models of pancreatic cancer. These experiments demonstrate remarkable activity of L-ANN in PDAC models and support future clinical studies. Citation Format: Ya'an Kang, Rafal Zielinski, Roberto Cardenas Zuniga, Radjendirane Venugopal, Maria Poimenidou, Magdalena Remiszewski, Shaohua Peng, Edd Felix, Krzysztof Grela, Stanislaw Skora, Van N. Nguyen, Izabela Fokt, Waldemar Priebe. High uptake, retention, and in vivo activity of L-Annamycin in pancreatic cancer models [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-066.