B16F10 melanoma supernatants neutralize the antiangiogenic effects of bortezomib in the CAM assay. (A) CAMs of 4-day-old chickens were incubated for 72 hours with control solution (−) or 0.1 ng of bortezomib/ring (+). Treatment with bortezomib inhibited CAM vascularization. (B) B16F10 melanoma xenografts were cultivated on the CAM for 5 days and treated daily with control solution (−) or 10 ng of bortezomib (+). Even at this high concentration, bortezomib had no antiangiogenic effects. B16F10 xenografts have a dark color. (C) CAMs were stimulated for 72 hours with supernatants of B16F10 melanoma cells in the presence of control solution (−) or 10 ng of bortezomib (+). Again, even at this high concentration, bortezomib had no antiangiogenic effects. Original magnification ×10. Images were acquired using an Olympus SZX10 stereomicroscope (2×/0.2 NA objective) with an Olympus E410 digital camera.