Evading Doxorubicin-Induced Systemic Immunosuppression Using Ultrasound-Responsive Liposomes Combined with Focused Ultrasound

Abstract

Doxorubicin (DOX) is a representative anticancer drug with a unique ability to induce immunogenic cell death of cancer cells. However, undesired toxicity on immune cells has remained a significant challenge, hindering the usage of DOX in cancer immunotherapy. Here, we report a combined therapy to avoid the off-target toxicity of DOX by adapting ultrasound-responsive liposomal doxorubicin and focused ultrasound exposure. Histological analysis demonstrated that the combined therapy induced less hemosiderosis of splenocytes and improved tumor infiltration of cytotoxic T lymphocytes. Additionally, in vivo therapeutic evaluation results indicate that the combined therapy achieved higher efficacy when combined with PD-1 immune-checkpoint blockade therapy by improving immunogenicity.

Keywords: cancer immunotherapy; doxorubicin; immune checkpoint blockade; immunogenic cell death.

Figure 1

Schematic illustration of DOX-mediated ICD and IMP301 and US-mediated ICD.

Figure 2

In vivo immunogenicity and systemic toxicity of the combination of IMP301 and US treatment. (a) Schematic illustration of the treatment protocol and (b) immunohistochemistry of mature APCs in tumor tissues. Blue: DAPI, Green: CD80. Scale bar represents 100 µm. (c) Hematoxylin and eosin-stained spleen tissues. Scale bar represents 500 µm. (d) Immunohistochemistry of infiltrated CTLs in tumor tissues. Blue: DAPI, Green: CD8. Scale bar represents 100 µm.

Figure 3

In vivo therapeutic efficacy of the combination of IMP301 and US in 4T1 tumor-bearing mice. (a) Schematic illustration of the treatment protocol; (b,c) changes in tumor size as a function of time. (d) Individual tumor growth in volume (n = 5).

Figure 4

In vivo toxicity of the combination of IMP301+US. (a) Changes in body weight and (b) H&E-stained liver, lung, kidney, and heart tissues. Scale bar represents 500 µm.

Figure 5

In vivo therapeutic efficacy of the combination of aPD1, IMP301, and US treatment in 4T1 tumor-bearing mice. (a) Schematic illustration of the treatment protocol; (b,c) changes in tumor size as a function of time. (d) Individual tumor growth in volume (n = 4).