Dual Photothermal/Chemotherapy of Melanoma Cells with Albumin Nanoparticles Carrying Indocyanine Green and Doxorubicin Leads to Immunogenic Cell Death

Recent focus on cancer immunotherapies has led to significant interest in the development of therapeutic strategies that can lead to immunogenic cell death (ICD), which can cause activation of an immune response against tumor cells and improve immunotherapy outcomes by enhancing the immunogenicity of the tumor microenvironment. In this work, a nanomedicine-mediated combination therapy is used to deliver the ICD inducers doxorubicin (Dox), a chemotherapeutic agent, and indocyanine green (ICG), a photothermal agent. These agents are loaded into nanoparticles (NPs) of bovine serum albumin (BSA) that are prepared through a desolvation process. The formulation of BSA NPs is optimized to achieve NPs of 102.6  nm in size and loadings of 8.55 % and 5.69 % (w/w) for ICG and Dox, respectively. The controlled release of these agents from the BSA NPs is confirmed. Upon laser irradiation for 2.5 min, NPs at a dose of 62.5 μg mL^-1 are able to increase the temperature of the cells by 7 °C and thereby inhibit the growth of B16F10 melanoma cells in vitro. Surface presentation of heat shock proteins and calreticulin from the cells after treatment confirmed the ability of the Dox/ICG loaded BSA NPs to induce ICD in the melanoma cells.

Induction of immunogenic cell death of cancer cells through nanoparticle-mediated dual chemotherapy and photothermal therapy

The use of nanomedicines to induce immunogenic cell death is a new strategy that aims to increase tumor immunogenicity and thereby prime tumors for further immunotherapies. In this study, we developed a nanoparticle formulation for combinatory chemotherapy and photothermal therapy based only on materials previously used in FDA-approved products and investigated the effect of the combinatory therapy on the growth inhibition and induction of immunogenic cell death in human MDA-MB-231 breast cancer cells. The formulation consists of ~108-nm nanoparticles made of poly(lactic acid)-b-methoxy poly(ethylene glycol) which carry doxorubicin for chemotherapy and indocyanine green for photothermal therapy. A 0.3 mg/mL suspension of NPs increased the medium temperature up to 10 °C upon irradiation with an 808-nm diode laser. In vitro studies showed that combination of laser assisted indocyanine green-mediated photothermal therapy and doxorubicin-mediated chemotherapy effectively eradicated cancer cells and resulted in the highest level of damage-associated molecular pattern presentation (calreticulin, high mobility group box 1, and adenosine triphosphate) compared to the individual treatments alone. These results demonstrate that our nanoparticle-mediated combinatory approach led to the most intense immunogenic cell death when compared to individual chemotherapy or photothermal therapy, making it a potent option for future in vivo studies in combination with cancer immunotherapies.