Novel calreticulin-nanoparticle in combination with focused ultrasound induces immunogenic cell death in melanoma to enhance antitumor immunity

• Published in: Theranostics Vol. 10; no. 8; pp. 3397 - 3412
• Main Authors: Sethuraman, Sri Nandhini, Singh, Mohit Pratap, Patil, Girish, Li, Shitao, Fiering, Steven, Hoopes, P Jack, Guha, Chandan, Malayer, Jerry, Ranjan, Ashish
• Format: Journal Article
• Language: English
• Published: Australia Ivyspring International Publisher Pty Ltd 01.01.2020; Ivyspring International Publisher
• Subjects: Adaptive Immunity - drug effects; Animals; Antigens; Apoptosis; B7-H1 Antigen - metabolism; Calreticulin - therapeutic use; CD47 Antigen - immunology; CD8-Positive T-Lymphocytes - immunology; Cell death; Cell Membrane - metabolism; Cloning; Combined Modality Therapy; Cytokines - immunology; Flow cytometry; Humans; Immunogenic Cell Death; Lymph Nodes - immunology; Melanoma; Melanoma, Experimental - immunology; Melanoma, Experimental - therapy; Mice; Microscopy; Nanoparticles; Nanoparticles - therapeutic use; Plasmids; Proteins; Research Paper; Spleen - immunology; Tumor-Associated Macrophages - immunology; Tumors; Ultrasonic imaging; Ultrasonic Therapy - methods; Xenograft Model Antitumor Assays; United States > US; calreticulin; melanoma; nanoparticle; Immunogenic cell death; focused ultrasound
• ISSN: 1838-7640; 1838-7640
• DOI: 10.7150/thno.42243

: Some studies have shown that the local activation of immunogenic cell death (ICD) by upregulating calreticulin (CRT) expression in solid tumors can improve antitumor effects. Although a promising approach, a key current challenge in ICD tumor therapy is the absence of a clinically translatable method for reproducibly inducing the CRT expression. Herein, we report a novel calreticulin-nanoparticle (CRT-NP) that enhances ICD and synergizes with focused ultrasound (FUS) to achieve local and systemic antitumor effects. : Full-length clone DNA of calreticulin was encapsulated in NPs made from DOTAP and cholesterol. Three CRT-NP intratumoral injections of 20 µg each were given 2 days apart, and FUS heating (42-45°C, ~15min) was applied sequentially 24h after each injection to induce ICD. To investigate ICD specific immune effect, the splenocytes of mice vaccinated with CRT-NP (± FUS) treated B16F10 cells were evaluated ex-vivo for TRP-2 antigen specific immunity. Additionally, the long-term protection was evaluated by re-challenging with the melanoma cells in the flank regions of tumor bearing mice. : CRT-NP plus FUS (CFUS) upregulated CRT expression, expanded the population of melanoma TRP-2 specific functional CD4+ and CD8+ T cells and tumor-suppressing M1 phenotype, and increased PD-1 and PD-L1 marker expression in the T cells. Therapeutically, CFUS suppressed B16 melanoma growth by >85% . that seen in untreated controls, and >~50% . CRT-NP or FUS alone, and prevented tumor growth in distal untreated sites. : CRT-NP amplifies the FUS and ICD therapeutic outcomes against melanoma, suggesting that the proposed combinatorial methodology may be clinically translatable.