PDF - 142K, Nude mice were subcutaneously injected with Panc-1 cells and therapy was started after 2 weeks. (A) Relative tumor growth is calculated by dividing the tumor volume at any time by the tumor volume at the start of treatment. (B) Net tumor growth was calculated by subtracting tumor volume on the first treatment day from that on the final day. Data are representative of mean values 9plus or minus) standard deviation from 6-8 mice per group.
ARTICLE ABSTRACT
Nanoparticle albumin–bound paclitaxel (nab-paclitaxel, NPT) has recently shown efficacy in pancreatic ductal adenocarcinoma (PDAC). Targeting tumor angiogenesis is a sensible combination therapeutic strategy for cancer, including PDAC. We tested the hypothesis that NPT response in PDAC can be enhanced by the mechanistically different antiangiogenic agents bevacizumab (Bev) or sunitinib (Su), despite its inherently increased tumor penetration and drug delivery. Compared with controls (19 days), median animal survival was increased after NPT therapy (32 days, a 68% increase, P = 0.0008); other regimens with enhanced survival were NPT+Bev (38 days, a 100% increase, P = 0.0004), NPT+Su (37 days, a 95% increase, P = 0.0004), and NPT+Bev+Su (49 days, a 158% increase, P = 0.0001) but not bevacizumab, sunitinib, or Bev+Su therapy. Relative to controls (100 ± 22.8), percentage net local tumor growth was 28.2 ± 23.4 with NPT, 55.6 ± 18 (Bev), 38.8 ± 30.2 (Su), 11 ± 7.2 (Bev+Su), 32.8 ± 29.2 (NPT+Bev), 6.6 ± 10.4 (NPT+Su), and 13.8 ± 12.5 (NPT+Bev+Su). Therapeutic effects on intratumoral proliferation, apoptosis, microvessel density, and stromal density corresponded with tumor growth inhibition data. In AsPC-1 PDAC cells, NPT IC50 was reduced >6-fold by the addition of sunitinib (IC25) but not by bevacizumab. In human umbilical vein endothelial cells (HUVEC), NPT IC50 (82 nmol/L) was decreased to 41 nmol/L by bevacizumab and to 63 nmol/L by sunitinib. In fibroblast WI-38 cells, NPT IC50 (7.2 μmol/L) was decreased to 7.8 nmol/L by sunitinib, but not by bevacizumab. These findings suggest that the effects of one of the most active cytotoxic agents against PDAC, NPT, can be enhanced with antiangiogenic agents, which clinically could relate to greater responses and improved antitumor results. Mol Cancer Ther; 13(5); 1032–43. ©2014 AACR.
