Abstract 2546: AXL targeted therapy blocks tumor progression and prevents tumor metastasis in pancreatic cancer

Abstract

Abstract Background: Metastasis and drug resistance are the major causes of mortality in patients with pancreatic ductal adenocarcinoma (PDA). Once developed, the progression of PDA metastasis is virtually unstoppable with current therapies. Accumulating evidence suggests important roles for the receptor tyrosine kinase AXL in cancer progression, invasion, metastasis, drug resistance, and patient mortality. Given the critical influence of metastasis on the clinical history of PDA, we hypothesize that pharmacological inhibition of AXL might inhibit tumor growth and prevent PDA metastasis. Methods: We investigated the AXL expression in a panel of human pancreatic cancer xenografts using Affymetrix gene array as well as qRT-PCR. We conducted a comprehensive preclinical trial to determine whether AXL targeted monotherapy, and in combination with gemcitabine, was effective in blocking PDA tumor progression and metastasis using subcutaneous as well as orthotopic pancreatic cancer models. Results: R428, a potent selective small molecule inhibitor of AXL, inhibited proliferation of pancreatic cancer cell lines in a concentration-dependent manner. A combination of R428 with gemcitabine could significantly inhibit primary tumor growth compared to gemcitabine treated mice. Notably, R428 alone and in combination with gemcitabine was remarkably effective in preventing the development of metastasis to organs and lymph nodes as compared to gemcitabine treatment in a highly aggressive orthotopic model. Conclusions: The data presented here provide strong evidence for the therapeutic development of AXL inhibitors as anti-metastatic agents in pancreatic cancer. A combination treatment of R428 and gemcitabine was highly effective in controlling the primary tumor growth and preventing metastatic spread. The novel therapeutic approach tested here has potential therapeutic implications for improving the current standard of care for PDA patients and to contribute towards making PDA a more manageable disease. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2546. doi:10.1158/1538-7445.AM2011-2546