Multifunctional Nanoparticles-Mediated PTT/PDT Synergistic Immune Activation and Antitumor Activity Combined with Anti-PD-L1 Immunotherapy for Breast Cancer Treatment

Introduction: Photoimmunotherapy is a breakthrough treatment for malignant tumors. Its uniqueness is that it uses antibody mediated targeted delivery to achieve high tumor specificity and uses laser-activated biophysical mechanism to accurately induce the rapid death of cancer cells and avoid damaging the surrounding normal tissues. Methods: In this paper, an iron-based micelle was designed to encapsulate the photothermal agent indocyanine green (ICG) and a cyclic tripeptide of arginine-glycine-aspartic acid (cRGD) as targeted multifunctional ICG@SANPs-cRGD nanoparticles for combined photothermal/photodynamic/immune therapy of breast cancer. Results: The experimental results show that ICG@SANPs-cRGD nanoparticles have good biocompatibility and photothermal conversion ability. Photothermal therapy (PTT) and photodynamic therapy (PDT) based on ICG@SANPs-cRGD can not only inhibit the proliferation, invasion and migration of tumor cells, but also directly kill tumor cells by inducing apoptosis or necrosis. Dual-mode fluorescence light (FL) and magnetic resonance imaging (MRI) imaging in mice confirmed the selective accumulation at tumor sites and imaging ability of ICG@SANPs-cRGD. PTT/PDT combined with Anti-PD-L1 immunotherapy based on ICG@SANPs-cRGD mediated the immunogenic cell death (ICD) of tumor cells by regulating the expression of immune-related indicators and activated the body's immune response mechanism, which enhanced the immunotherapy effect of immune checkpoint block (ICB). PTT/PDT combined with Anti-PD-L1 therapy not only prevented the progression of the primary tumor but also inhibited the distant metastasis of the tumor. Discussion: This study explores the biomedical application of PTT/PDT combined with Anti-PD-L1 based on ICG@SANPs-cRGD nanomaterials for breast cancer treatment and demonstrates the potential of ICG@SANPs-cRGD as a multifunctional therapeutic platform for future cancer therapy.