Combination of tumor-lysate pulsed dendritic cells and anti-angiogenic drug TNP-470 induces regression of mouse orthotopic pancreatic cancer

Abstract

[Backgroundl Most cases of pancreatic cancer are inoperable when diagnosed. In these cases immunotherapy, which targets cancer cells, is one of the potent options. On the other hand, anti-anglogenic therapy, which targets tumor vessels, has been reported to be promising for solid tumors. However, single therapy of these has not induced tumor regression within a therapeutic dose. Therefore, in this study, we examined whether the combination of immunotherapy with DCs and anti-angiogenetic drug TNP-470 induces tumor regression and tested the effectiveness of tumor lysate (TL) pulsation for DCs. [Matenals& Methods] 3x105 mouse pancreatic adenocarcinoma cells (pan02 origanated rum C57/BL6) were orthotopically inoculated into the pancreas of C57/BL6 mouse 3~4 weeks of age. Tumor take ratio was 100% at 6 weeks. 3xl04DCs were injected into peritoneal cavity at 4 and 5weeks. TNP-470 (100mg/kg/week) was injected subcutaneously into tumor-bearing mice every other day from 4 weeks to 6weeks. We measured tumor volume, vascular density, and vessel diameter by the injection of FITC-dextran using intravital microscope at 6weeks. Proliferation and apoptosis of cancer cells were evaluated by PCNA and TUNEL. We compared anticancer effect among 5 groups, which are DCs with TL (+TL), DCs without TL (-TL), DCs with TL +TNP-470 (TNP+TL), DCs without TL + TNP-470 (TNP-TL), and control (without DC and without TNP-470). [Results] Tumor volume was 22.5 +_ 7.6ram 3 in + TL, 2 6 7 _ + i1 0mmqn -TL, 4.8_+2.5 mm ~ in TNP+ TL, and 31.2 _+ 20.4mm 3 in TNPTL, and these numbers were significantly smaller compared with 113.7 _+ 38.6mm3in control. Tumor vascular density was 36.4 _+ 4.4cm/cm z in + TL, 33.8-+ 5.6cm/cm 2 in -TL, 21.3 _+ 4.3cm/cm: in TNP + TL, and 28.5 _+ 4.4cm/cm z in TNP-TL, and these numbers were significantly smaller than 88.8-+ 7.3cm/cm 2 in control. Tumor vessel diameter was 9.9-+ 19/*m in TNP+TL, 8.5 +0 .8~m in TNP-TL and these data were smaller than 22.1 _+ 1.0~min control, J.8.9_+ 2.9~m in + TL, and 17.3 _+ 3.7/*m in -TL. There were not significant differences in proliferation among 5 groups, however, the number of apoptotic cells tend to be larger in +TL groups than -TL groups. There were not oh',nons side effects in all groups. [Conclusion] Data suggested that tumor-lysate pulsed DCs combined with FNP-470 induced regression of orthotopic pancreatic cancer growth, possibly through the induction of cancer cell apoptosis and anti-angiogenic effect.