Figure 4. Targeted H2009.1 and control liposomes accumulate in tumors and clear through the liver and spleen.

Subcutaneous α_vβ₆-positive H2009 or α_vβ₆-negative H460 tumors were established in the right flank of NOD/SCID mice. Tumor bearing mice were injected via tail vein with either 1.3% H2009.1 tetrameric, AcH2009.1 tetrameric, scH2009.1 tetrameric, or naked liposomes labeled with the near infrared dye DiR. At 72 hours post-injection, the mice were sacrificed and the tumors and organs removed for ex vivo fluorescent imaging. (A) Representative images of liposome accumulation in tumors and organs from α_vβ₆-positive H2009 tumor bearing mice. Like the in vivo imaging in Figure 3, despite the α_vβ₆-targeting abilities of the H2009.1 peptide, all liposome formulations except for the AcH2009.1 tetrameric liposomes accumulated in tumors to the same extent. (B) Representative images of liposome accumulation in tumors and organs from α_vβ₆-negative H460 tumor bearing mice. Similar to the in vivo imaging in Figure 3, the H2009.1 tetrameric and scH2009.1 tetrameric liposomes accumulated in tumors to the same extent, with the AcH2009.1 and naked liposomes accumulating in tumors at levels that are 2-fold lower.