Dual-responsive supramolecular photodynamic nanomedicine with activatable immunomodulation for enhanced antitumor therapy

A major challenge facing photodynamic therapy (PDT) is that the activity of the immune-induced infiltrating CD8+ T cells is subject to the regulatory T lymphocytes (Tregs), leaving the tumor at risk of recurrence and metastasis after the initial ablation. To augment the antitumor response and reprogram the immunosuppressive tumor microenvironment (TME), a supramolecular photodynamic nanoparticle (DACss) is constructed by the host-guest interaction between demethylcantharidin-conjugated β-cyclodextrin (DMC-CD) and amantadine-terminated disulfide-conjugated FFVLGGGC peptide with chlorin e6 decoration (Ad-ss-pep-Ce6) to achieve intelligent delivery of photosensitizer and immunomodulator for breast cancer treatment. The acid-labile β-carboxamide bond of DMC-CD is hydrolyzed in response to the acidic TME, resulting in the localized release of DMC and subsequent inhibition of Tregs. The guest molecule Ad-ss-pep-Ce6 can be cleaved by a high level of intracellular GSH, reducing photosensitizer toxicity and increasing photosensitizer retention in the tumor. With a significant increase in the CTL/Treg ratio, the combination of Ce6-based PDT and DMC-mediated immunomodulation adequately achieved spatiotemporal regulation and remodeling of the TME, as well as improved primary tumor and in situ lung metastasis suppression with the aid of PD-1 antibody.

Anti-PD-L1 antibody enhances curative effect of cryoablation via antibody-dependent cell-mediated cytotoxicity mediating PD-L1highCD11b+ cells elimination in hepatocellular carcinoma

Cryoablation (CRA) and microwave ablation (MWA) are two main local treatments for hepatocellular carcinoma (HCC). However, which one is more curative and suitable for combining with immunotherapy is still controversial. Herein, CRA induced higher tumoral PD-L1 expression and more T cells infiltration, but less PD-L1highCD11b+ myeloid cells infiltration than MWA in HCC. Furthermore, CRA had better curative effect than MWA for anti-PD-L1 combination therapy in mouse models. Mechanistically, anti-PD-L1 antibody facilitated infiltration of CD8+ T cells by enhancing the secretion of CXCL9 from cDC1 cells after CRA therapy. On the other hand, anti-PD-L1 antibody promoted the infiltration of NK cells to eliminate PD-L1highCD11b+ myeloid cells by antibody-dependent cell-mediated cytotoxicity (ADCC) effect after CRA therapy. Both aspects relieved the immunosuppressive microenvironment after CRA therapy. Notably, the wild-type PD-L1 Avelumab (Bavencio), compared to the mutant PD-L1 atezolizumab (Tecentriq), was better at inducing the ADCC effect to target PD-L1highCD11b+ myeloid cells. Collectively, our study uncovered the novel insights that CRA showed superior curative effect than MWA in combining with anti-PD-L1 antibody by strengthening CTL/NK cell immune responses, which provided a strong rationale for combining CRA and PD-L1 blockade in the clinical treatment for HCC.

Sequential delivery of PD-1/PD-L1 blockade peptide and IDO inhibitor for immunosuppressive microenvironment remodeling via an MMP-2 responsive dual-targeting liposome

Intelligent responsive drug delivery system opens up new avenues for realizing safer and more effective combination immunotherapy. Herein, a kind of tumor cascade-targeted responsive liposome (NLG919@Lip-pep1) is developed by conjugating polypeptide inhibitor of PD-1 signal pathway (AUNP-12), which is also a targeted peptide that conjugated with liposome carrier through matrix metalloproteinase-2 (MMP-2) cleavable peptide (GPLGVRGD). This targeted liposome is prepared through a mature preparation process, and indoleamine-2,3-dioxygenase (IDO) inhibitor NLG919 was encapsulated into it. Moreover, mediated by the enhanced permeability and retention effect (EPR effect) and AUNP-12, NLG919@Lip-pep1 first targets the cells that highly express PD-L1 in tumor tissues. At the same time, the over-expressed MMP-2 in the tumor site triggers the dissociation of AUNP-12, thus realizing the precise block of PD-1 signal pathway, and restoring the activity of T cells. The exposure of secondary targeting module II VRGDC-NLG919@Lip mediated tumor cells targeting, and further relieved the immunosuppressive microenvironment. Overall, this study offers a potentially appealing paradigm of a high efficiency, low toxicity, and simple intelligent responsive drug delivery system for targeted drug delivery in breast cancer, which can effectively rescue and activate the body's anti-tumor immune response and furthermore achieve effective treatment of metastatic breast cancer.

The roles and clinical controversies of radiotherapy and immunotherapy in abscopal effect / 中华放射肿瘤学杂志

As early as the 20 th century, it has been observed that radiotherapy (RT), as a local therapy, can activate the adaptive immune system, resulting in spontaneous regression of tumors out of the radiation field, which is known as "abscopal effect". Although the occurrence of abscopal effect is still rare, with the gradual increase in the application of immunotherapy, more and more clinical cases of abscopal effect have been reported. Increasing attention has been paid to the therapeutic potential of RT in inducing systemic anti-tumor response. Especially, the combination of RT and immunotherapy enhances the research value of abscopal effect. However, its mechanism has not been fully elucidated, and the optimal timing, dose and fractionation of RT are also under study. How to classify the beneficiary groups is also a key issue. In this article, the history of abscopal effect, and the role of RT and immunotherapy in this phenomenon were briefly introduced, and the existing controversies in clinical application were illustrated, aiming to clarify the direction of current research and development and open a new chapter for tumor treatment in a short period of time.

Fucoidan-functionalized activated platelet-hitchhiking micelles simultaneously track tumor cells and remodel the immunosuppressive microenvironment for efficient metastatic cancer treatment

Tumor metastasis is responsible for most mortality in cancer patients, and remains a challenge in clinical cancer treatment. Platelets can be recruited and activated by tumor cells, then adhere to circulating tumor cells (CTCs) and assist tumor cells extravasate in distant organs. Therefore, nanoparticles specially hitchhiking on activated platelets are considered to have excellent targeting ability for primary tumor, CTCs and metastasis in distant organs. However, the activated tumor-homing platelets will release transforming growth factor-β (TGF-β), which promotes tumor metastasis and forms immunosuppressive microenvironment. Therefore, a multitalent strategy is needed to balance the accurate tumor tracking and alleviate the immunosuppressive signals. In this study, a fucoidan-functionalized micelle (FD/DOX) was constructed, which could efficiently adhere to activated platelets through P-selectin. Compared with the micelle without P-selectin targeting effect, FD/DOX had increased distribution in both tumor tissue and metastasis niche, and exhibited excellent anti-tumor and anti-metastasis efficacy on 4T1 spontaneous metastasis model. In addition, due to the contribution of fucoidan, FD/DOX treatment was confirmed to inhibit the expression of TGF-β, thereby stimulating anti-tumor immune response and reversing the immunosuppressive microenvironment. The fucoidan-functionalized activated platelets-hitchhiking micelle was promising for the metastatic cancer treatment.

Cancer stem cell-targeted chimeric antigen receptor (CAR)-T cell therapy: Challenges and prospects

Cancer stem cells (CSCs) with their self-renewal ability are accepted as cells which initiate tumors. CSCs are regarded as interesting targets for novel anticancer therapeutic agents because of their association with tumor recurrence and resistance to conventional therapies, including radiotherapy and chemotherapy. Chimeric antigen receptor (CAR)-T cells are engineered T cells which express an artificial receptor specific for tumor associated antigens (TAAs) by which they accurately target and kill cancer cells. In recent years, CAR-T cell therapy has shown more efficiency in cancer treatment, particularly regarding blood cancers. The expression of specific markers such as TAAs on CSCs in varied cancer types makes them as potent tools for CAR-T cell therapy. Here we review the CSC markers that have been previously targeted with CAR-T cells, as well as the CSC markers that may be used as possible targets for CAR-T cell therapy in the future. Furthermore, we will detail the most important obstacles against CAR-T cell therapy and suggest solutions.

Progress of tumor-associated myeloid cells in multiple myeloma / 白血病·淋巴瘤

Multiple myeloma (MM) is a kind of hematologic malignancy. Although there are lots of therapies for MM, it is still incurable. Except for the drug-resistance, another important reason for the incurability is the immunosuppressive effect derived from interactions between tumor cells and the bone marrow microenvironment, which makes our body cannot clear resident tumor cells completely. As a vital part in the immunosuppressive microenvironment, tumor-associated myeloid cells (TAMC) play an extremely significant role in the immune escape of MM and become the reason for limiting the effectiveness of immunotherapy, furthermore, TAMC have become potential targets for the treatment of MM. This article reviews the composition and the latest progress of the mechanisms of TAMC in the immune microenvironment of MM.

Nanomedicines modulating tumor immunosuppressive cells to enhance cancer immunotherapy

Cancer immunotherapy has veered the paradigm of cancer treatment. Despite recent advances in immunotherapy for improved antitumor efficacy, the complicated tumor microenvironment (TME) is highly immunosuppressive, yielding both astounding and unsatisfactory clinical successes. In this regard, clinical outcomes of currently available immunotherapy are confined to the varied immune systems owing in large part to the lack of understanding of the complexity and diversity of the immune context of the TME. Various advanced designs of nanomedicines could still not fully surmount the delivery barriers of the TME. The immunosuppressive TME may even dampen the efficacy of antitumor immunity. Recently, some nanotechnology-related strategies have been inaugurated to modulate the immunosuppressive cells within the tumor immune microenvironment (TIME) for robust immunotherapeutic responses. In this review, we will highlight the current understanding of the immunosuppressive TIME and identify disparate subclasses of TIME that possess an impact on immunotherapy, especially those unique classes associated with the immunosuppressive effect. The immunoregulatory cell types inside the immunosuppressive TIME will be delineated along with the existing and potential approaches for immunosuppressive cell modulation. After introducing the various strategies, we will ultimately outline both the novel therapeutic targets and the potential issues that affect the efficacy of TIME-based nanomedicines.

New strategies for CAR-T cell in the treatment of solid tumors / 中国肿瘤生物治疗杂志

@# Chimeric antigen receptor modified T (CAR-T) cell, a novel adoptive immunotherapy strategy, has been used successfully against hematological tumors. However, in solid tumors, due to multiple immunosuppressive cells, immunosuppressive molecules, and extracellular matrix play a suppressive role in the cytotoxic effects of migrating CAR-T cells and severely inhibit the antitumor efficacy of CAR-T cells in the tumor microenvironment of solid tumors. Simultaneously, tumor heterogeneity, lacking proper tumor antigens, poor homing ability at solid tumor sites, along with off-target effect, resulting in poor therapeutic effect of CAR-T cells in solid tumors. Compared with hematological tumors, solid tumors have complex biological characteristics, and thus targeted strategies are demanded to ensure long-term efficacy of CAR-T cells against tumors. This review makes a summary of the development of CAR-T cells, the confusion in solid tumors and the progress of treatment strategies.

Role of tumor-associated myeloid cells in the formation of immune microenvironment in multiple myeloma / 白血病·淋巴瘤

Although great progress has been made in the treatment of multiple myeloma (MM), it is still an incurable malignant plasma cell tumor. In addition to the MM cell itself, the bone marrow microenvironment also plays a critically important role to prompt MM cell's survival, growth, and drug resistance. Bone microenvironment reformed by MM cells could not only help the proliferation of MM cells, but also inhibit the killing of the immune system to MM. A variety of cell components and mechanisms participate in the formation of immune microenvironment, including high-profile tumor associated myeloid cells (TAMC). This paper introduces the mechanisms of TAMC in MM immunosuppressive microenvironment.

Study progresses of tumor immunosuppressive microenvironment in tumor immunotherapy / 实用肿瘤学杂志

Immunosuppressive tumor microenvironment is a part of the tumor microenvironment that plays an immunosuppressive function.It consists of suppressor cells and inhibitory cytokines.In recent years,be-cause of its important role in tumor immunity,CAR-T and PD-1/PD-L1 signal pathway has become a hot top-ic of immunotherapy, which can suppress immune through different mechanisms to promote tumor progression. Therefore,taking more effective anti-tumor therapies against the above mechanisms is possible to rescue the pro-gress of tumor.In this article,the influence of immunosuppression microenvironment in CAR-T cell therapy and PD-1/PD-L1 signaling pathway in the anti-tumor process is reviewed.