Abstract 5387: Combination treatment benefits of EMAP II with doxorubicin, docetaxel and gemcitabine in experimental pancreatic cancer

Abstract

Abstract Purpose: Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal cancer that grows rapidly, metastasizes early, and is very resistant to conventional chemotherapy. Gemcitabine, the standard first-line chemotherapeutic agent for advanced and metastatic PDAC, showed limited benefits as single agent or in combination. Endothelial monocyte activating polypeptide II (EMAP) is an antiendothelial and antiangiogenic cytokine that has been shown to enhance gemcitabine effects in PDAC. The present study evaluated the antitumor effects of combination of EMAP with doxorubicin and docetaxel in experimental PDAC. Methods: Human ASPC-1 PDAC cells and endothelial cells (HUVECs) were grown in RPMI and E-Stim medium, respectively. Cell proliferation and protein expression were analyzed by WST-1 assay and Western blotting, respectively. Apoptosis was detected by Annexin-V / propidium iodide (PI) staining. In vivo murine xenograft survival was measured after treatment with EMAP, doxorubicin, docetaxel and gemcitabine. Results: In vitro evaluation of inhibition in ASPC-1 cell proliferation showed no effect of EMAP, modest effects of doxorubicin and gemcitabine (IC50>10 μM) and major effects of docetaxel (IC50= 8μM); percent inhibition in cell proliferation at 10 μM concentration was 1.4, 26.5, 40 and 60, respectively. EMAP addition to doxorubicin, docetaxel or gemcitabine did not increase the effects of single agents. In HUVECs, EMAP, doxorubicin, docetaxel and gemcitabine all had significant antiproliferative effects, and percent inhibition at 10 μM concentration was 59, 79, 96 and 85, respectively. Addition of EMAP to doxorubicin, docetaxel and gemcitabine in lower concentrations (10 nM, 100 nM and 1 μM) had significant additive antiprolifertative effects. In ASPC-1 cells, no agent induced measurable apoptosis, but in HUVECs all agents either alone or in combination significantly induced apoptosis as observed by Annexin V / PI staining, PARP cleavage and phospho-JNK expression. In vivo animal survival study showed that compared to control (median survival: 21 days), EMAP (20 d) had no benefit, while doxorubicin (31 d), docetaxel (35 d) and gemcitabine (32 d) monotherapy extended overall survival. Compared to single agent therapy, combination of EMAP with docetaxel (44 d) or gemcitabine (38 d) enhanced the survival, but the combination of EMAP with doxorubicin (31 d) had no additional benefit. Conclusion: In vitro EMAP addition increased the antiproliferative and proapoptotic activity of doxorubicin, docetaxel and gemcitabine in endothelial cells but not in PDAC cells. In vivo, addition of EMAP enhanced the docetaxel and gemcitabine effect, but not that of doxorubicin, on overall animal survival. The antiendothelial combination therapy benefit through EMAP is not limited to gencitabine, and may facilitate the development of more effective therapeutic strategies for PDAC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5387.