Theranostic Agent Combining Fullerene Nanocrystals and Gold Nanoparticles for Photoacoustic Imaging and Photothermal Therapy

Developing photoactivatable theranostic platforms with integrated functionalities of biocompatibility, targeting, imaging contrast, and therapy is a promising approach for cancer diagnosis and therapy. Here, we report a theranostic agent based on a hybrid nanoparticle comprising fullerene nanocrystals and gold nanoparticles (FGNPs) for photoacoustic imaging and photothermal therapy. Compared to gold nanoparticles and fullerene crystals, FGNPs exhibited stronger photoacoustic signals and photothermal heating characteristics by irradiating light with an optimal wavelength. Our studies demonstrated that FGNPs could kill cancer cells due to their photothermal heating characteristics in vitro. Moreover, FGNPs that are accumulated in tumor tissue via the enhanced permeation and retention effect can visualize tumor tissue due to their photoacoustic signal in tumor xenograft model mice. The theranostic agent with FGNPs shows promise for cancer therapy

Novel quantitative immunohistochemical analysis for evaluating PD-L1 expression with phosphor-integrated dots for predicting the efficacy of patients with cancer treated with immune checkpoint inhibitors

IntroductionProgrammed cell death ligand 1 (PD-L1) expression in tumor tissues is measured as a predictor of the therapeutic efficacy of immune checkpoint inhibitors (ICIs) in many cancer types. PD-L1 expression is evaluated by immunohistochemical staining using 3,3´-diaminobenzidine (DAB) chronogenesis (IHC-DAB); however, quantitative and reproducibility issues remain. We focused on a highly sensitive quantitative immunohistochemical method using phosphor-integrated dots (PIDs), which are fluorescent nanoparticles, and evaluated PD-L1 expression between the PID method and conventional DAB method.MethodsIn total, 155 patients with metastatic or recurrent cancer treated with ICIs were enrolled from four university hospitals. Tumor tissue specimens collected before treatment were subjected to immunohistochemical staining with both the PID and conventional DAB methods to evaluate PD-L1 protein expression.ResultsPD-L1 expression assessed using the PID and DAB methods was positively correlated. We quantified PD-L1 expression using the PID method and calculated PD-L1 PID scores. The PID score was significantly higher in the responder group than in the non-responder group. Survival analysis demonstrated that PD-L1 expression evaluated using the IHC-DAB method was not associated with progression-free survival (PFS) or overall survival (OS). Yet, PFS and OS were strikingly prolonged in the high PD-L1 PID score group.ConclusionQuantification of PD-L1 expression as a PID score was more effective in predicting the treatment efficacy and prognosis of patients with cancer treated with ICIs. The quantitative evaluation of PD-L1 expression using the PID method is a novel strategy for protein detection. It is highly significant that the PID method was able to identify a group of patients with a favorable prognosis who could not be identified by the conventional DAB method

がん治療ワクチンに向けた自己組織化ナノゲルを基盤とする抗原デリバリーシステムの開発

付記する学位プログラム名: 充実した健康長寿社会を築く総合医療開発リーダー育成プログラム京都大学0048新制・課程博士博士(工学)甲第22469号工博第4730号新制||工||1739(附属図書館)京都大学大学院工学研究科高分子化学専攻(主査)教授 秋吉 一成, 教授 近藤 輝幸, 教授 梅田 眞郷学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDGA

Structural effects and lymphocyte activation properties of self-assembled polysaccharide nanogels for effective antigen delivery

The success of immunotherapeutic vaccines is often limited by their inability to activate the cytotoxic T lymphocyte (CTL)-inducing Th1 pathway. We investigated the ability of self-assembled nanogels (CHP or CH-CDex) to activate this pathway, and characterised them chemically and biologically. Once loaded with antigen (ovalbumin, OVA) their OVA encapsulation and dissociation rates suggested the possibility of effective antigen delivery. The DC2.4 dendritic cell line took up either vaccine time-dependently, but both vaccines required CpG DNA for class I MHC presentation. The nanogel vaccines interacted with RAW264.7, a Balb/c mouse-derived macrophage cell line, and co-localised with lysosomes, suggesting their endocytotic internalization in RAW264.7. Both vaccines activated CTLs better than OVA alone. Unlike OVA alone, the nanogel vaccines induced IgG2a antibody production in mice, whereas the former induced IgG1 antibodies. OVA-nanogel delivery to the draining lymph nodes (DLNs) was higher than that for OVA alone, reaching a deeper medullary area. Furthermore, Langerin⁺ CD103⁺ DCs interacted with the nanogel vaccines effectively, which is a subset of cross-presentation DC, in the DLNs. The nanogel vaccines each had good anti-tumour efficacy in OVA tumour-bearing mice compared with the OVA alone. Thus, CHP and CH-CDex nanogels should be investigated further because of the great potential they offer for immunotherapy

Synergistic anti-tumor efficacy by combination therapy of a self-assembled nanogel vaccine with an immune checkpoint anti-PD-1 antibody

Therapeutic strategies for cancer involving immune checkpoint inhibitors (ICIs) have been gaining widespread attention, but their efficacy remains limited. Thus, combination of ICI therapies with other therapeutic modalities may be required to improve their outcomes. In this study, we examined the improved efficacy of a CHP nanogel-based vaccine delivery system after combination with ICI therapy. For this, we evaluated the therapeutic efficacy of combining an anti-PD-1 antibody as an ICI with an OVA antigen-complexed CHP nanogel vaccine delivery system in a mouse E.G7-OVA tumor model. Mice were subcutaneously inoculated with E.G7-OVA tumor cells on one side of the back, and subcutaneously injected with OVA or the OVA/CHP nanogel vaccine on the other side of the back. Anti-PD-1 antibody was administered at defined intervals. Tumor volume, immune responses, and tumor-infiltrating cells were evaluated. Mice treated with OVA vaccine alone showed weak tumor suppression compared with untreated control mice. Mice receiving combined OVA/CHP nanogel vaccine and anti-PD-1 antibody therapy exhibited strong tumor growth suppression and markedly improved survival, suggesting that PD-1 signaling blockade by the anti-PD-1 antibody enhanced the anti-tumor efficacy of the OVA vaccine. Furthermore, tumor-infiltrating cells and immune responses were increased in the combined therapy group. No serious side effects were observed for any of the treatments. Taken together, the immune system activation induced by the CHP nanogel vaccine was synergistically enhanced by the anti-PD-1 antibody. The present findings suggest the potential for enhanced therapeutic efficacy by combining the CHP nanogel vaccine delivery system with ICI therapy for various cancer types

Synthesis of oxytocin derivatives lipidated via a carbonate or carbamate linkage as a long-acting therapeutic agent for social impairment-like behaviors

In the course of our studies of hydrophobic oxytocin (OT) analogues, we newly synthesized lipidated OT (LOT-4a-c and LOT-5a-c), in which a long alkyl chain (C14-C16) is conjugated via a carbonate or carbamate linkage at the Tyr-2 phenolic hydroxy group and a palmitoyl group at the terminal amino group of Cys-1. These LOTs did not activate OT and vasopressin receptors. Among the LOTs, however, LOT-4c, having a C16-chain via a carbonate linkage at the phenolic hydroxyl group of the Tyr-2, showed very long-lasting action for the recovery of impaired social behavior in CD38 knockout mice, a rodent model of autistic phenotypes, whereas the effect of OT itself rapidly diminished. These results indicate that LOT-4c may serve as a potential prodrug in mice

Engineered collagen-binding serum albumin as a drug conjugate carrier for cancer therapy

Serum albumin (SA) is used as a carrier to deliver cytotoxic agents to tumors via passive targeting. To further improve SA's tumor targeting capacity, we sought to develop an approach to retain SA-drug conjugates within tumors through a combination of passive and active targeting. SA was recombinantly fused with a collagen-binding domain (CBD) of von Willebrand factor to bind within the tumor stroma after extravasation due to tumor vascular permeability. Doxorubicin (Dox) was conjugated to the CBD-SA via a pH-sensitive linker. Dox-CBD-SA treatment significantly suppressed tumor growth compared to both Dox-SA and aldoxorubicin treatment in a mouse model of breast cancer. Dox-CBD-SA efficiently stimulated host antitumor immunity, resulting in the complete eradication of MC38 colon carcinoma when used in combination with anti-PD-1 checkpoint inhibitor. Dox-CBD-SA decreased adverse events compared to aldoxorubicin. Thus, engineered CBD-SA could be a versatile and clinically relevant drug conjugate carrier protein for treatment of solid tumors