Transformable prodrug nanoplatform via tumor microenvironment modulation and immune checkpoint blockade potentiates immunogenic cell death mediated cancer immunotherapy

Synergistic chemo-immunotherapy for osteosarcoma via a pH-responsive multi-component nanoparticle system

Introduction

Osteosarcoma (OS) is the most common primary malignant bone tumor in pediatric populations. Its treatment is complicated by chemotherapy-induced toxicity and limited induction of immunogenic cell death (ICD).

Methods

To address these challenges, we developed a pH-responsive, multi-component nanoparticle system designed to co-deliver doxorubicin (DOX), monophosphoryl lipid A (MPLA), and a PD-1/PD-L1-targeting peptide, integrated with the immune-modulating polymer PEG-PC7A. The system was optimized using both one-factor-at-a-time (OFAT) and Box-Behnken design (BBD).

Results

The optimized nanoparticles had a hydrodynamic size of 110 nm, high encapsulation efficiency (97.15%), and pH-sensitive drug release (91% at pH 6.5). In vitro studies showed enhanced ICD markers, including calreticulin exposure and ATP/HMGB1 release, aswell as synergistic dendritic cell maturation via dual STING/TLR4 pathway activation. In an orthotopic LM8 osteosarcoma model, the nanoparticles significantly suppressed tumor growth, promoted cytotoxic T lymphocyte infiltration, reduced regulatory T cells, and established long-term immune memory.

Discussion

The combination of ICD induction, innate immune activation, and checkpoint blockade reprogrammed the tumor microenvironment, amplifying anti-tumor immune responses. These results demonstrate the potential of this multifunctional nanoparticle platform as an effective immunochemotherapeutic strategy for osteosarcoma, offering enhanced therapeutic efficacy and reduced systemic toxicity.

Regulation of cancer-associated fibroblasts for enhanced cancer immunotherapy using advanced functional nanomedicines: an updated review

The tumor microenvironment (TME) is a complex and dynamic ecosystem that plays a critical role in cancer progression. It comprises various cell types, including immune cells, tumor cells, and stromal cells. Among these, cancer-associated fibroblasts (CAFs) represent a heterogeneous population with diverse origins, phenotypes, and functions. Activated CAFs secrete multiple factors that promote tumor growth, migration, angiogenesis, and contribute to chemoresistance. Additionally, CAFs secrete extracellular matrix (ECM) components, such as collagen, which form a physical barrier that hinders the penetration of chemotherapeutic and immunotherapeutic agents. This ECM also influences immune cell infiltration, impeding their ability to effectively target tumor cells. As a result, modulating the activity of CAFs has emerged as a promising strategy to enhance the efficacy of tumor immunotherapy. Nano-delivery systems, constructed from various nanomaterials with high targeting specificity and biocompatibility, offer a compelling approach to deliver therapeutic agents or immunomodulatory factors directly to CAFs. This modulation can alter CAF function, reduce their tumor-promoting effects, and thereby improve the outcomes of immunotherapy. This review provides an in-depth exploration of the origins, functions, and interactions of CAFs within the TME, particularly in the context of immune suppression. Furthermore, it discusses the potential applications of functional nanocarrifers in modulating CAFs and enhancing the effectiveness of tumor immunotherapy, highlighting the significant progress and potential of nanotechnology in this area.

PD-L1 peptides in cancer immunoimaging and immunotherapy

The interaction between programmed death protein 1 (PD-1) and programmed death ligand 1 (PD-L1) constitutes a critical immune checkpoint pathway that leads to immune tolerance in cancer cells and impacts antitumor treatment. Monoclonal antibody blockade of the PD-L1 immunoinhibitory pathway has demonstrated significant and lasting clinical antitumor responses. Furthermore, PD-L1 serves as an important biomarker for predicting the effectiveness of immune checkpoint inhibitors (ICIs). To date, numerous studies based on monoclonal antibodies have been carried out to detect the expression levels of PD-L1 and predict the antitumor effectiveness of PD-L1 ICIs. However, due to the deficiencies of monoclonal antibodies, researches of PD-L1 peptides have received increasing attention. PD-L1 peptides present promising candidates due to their advantages, including reduced manufacturing costs, enhanced stability, decreased immunogenicity, faster clearance and improved tumor or organ penetration, thereby offering broad application prospects in cancer immunoimaging and immunotherapy. In this review, we analyze the existing evidence on PD-L1 peptides in cancer immunoimaging and immunotherapy. First, the design techniques of different types of PD-L1 targeting peptides and their strengths and weaknesses are briefly introduced. Second, the recent advancements in immunoimaging and the development trends in immunotherapy are summarized. Finally, the existing challenges and future directions in this field are comprehensively deliberated.

Hyaluronic acid-functionalized supramolecular nanophotosensitizers for targeted photoimmunotherapy of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is recognized as a particularly aggressive subtype of breast cancer that is devoid of effective therapeutic targets. Immune checkpoint inhibitors (ICIs) have demonstrated promising results in TNBC treatment. Nonetheless, most patients either develop resistance to ICIs or fail to respond to them initially. Owing to its spatio-temporal precision and non-invasive nature, photoimmunotherapy offers a targeted therapeutic strategy for TNBC. Herein, we report hyaluronic acid (HA)-functionalized indocyanine green-based supramolecular nanoparticles (HGI NPs), with biodegradable characteristics, for high-performance photoacoustic imaging and targeted phototherapy for TNBC. Notably, HGI NPs can significantly gather in TNBC tissues because of the enhanced permeability and retention effect of the tumor, and the tumor-targeting properties of HA. The strong amplification of HGI nanoparticles triggers a significant immunogenic cell death (ICD) response when exposed to 808 nm light, thus shifting the immunosuppressive tumor microenvironment (iTME) into a tumor attack mode and 'hot' state. Antitumor experiments demonstrate the high efficiency of the supramolecular photosensitizers HGI NPs for TNBC elimination and good biosafety. This synergistic strategy reshapes the iTME and amplifies the antitumor immune response, providing a theoretical foundation for combining phototherapy and ICIs as potential treatments for TNBC.

Targeting Cancer: Microenvironment and Immunotherapy Innovations

In 2024, the United States was projected to experience 2 million new cancer diagnoses and approximately 611,720 cancer-related deaths, reflecting a broader global trend in which cancer cases are anticipated to exceed 35 million by 2050. This increasing burden highlights ongoing challenges in cancer treatment despite significant advances that have reduced cancer mortality by 31% since 1991. Key obstacles include the disease's inherent heterogeneity and complexity, such as treatment resistance, cancer stem cells, and the multifaceted tumor microenvironment (TME). The TME-comprising various tumor and immune cells, blood vessels, and biochemical factors-plays a crucial role in tumor growth and resistance to therapies. Recent innovations in cancer treatment, particularly in the field of immuno-oncology, have leveraged insights into TME interactions. An emerging example is the FDA-approved therapy using tumor-infiltrating lymphocytes (TILs), demonstrating the potential of cell-based approaches in solid tumors. However, TIL therapy is just one of many strategies being explored. This review provides a comprehensive overview of the emerging field of immuno-oncology, focusing on how novel therapies targeting or harnessing components of the TME could enhance treatment efficacy and address persistent challenges in cancer care.

Nanotechnology-Based Strategies for Safe and Effective Immunotherapy

Cancer immunotherapy using immune checkpoint blockades has emerged as a promising therapeutic approach. However, immunotherapy faces challenges such as low response rates in solid tumors, necessitating strategies to remodel the immune-suppressive tumor microenvironment (TME) into an immune-activated state. One of the primary approaches to achieve this transformation is through the induction of immunogenic cell death (ICD). Herein, we discussed strategies to maximize ICD induction using nanoparticles. In particular, this review highlighted various studies integrating chemotherapy, radiation therapy (RT), photodynamic therapy (PDT), and photothermal therapy (PTT) with nanoparticle-based immunotherapy. The research covered in this review aims to provide valuable insights for future studies on nanoparticle-assisted immunotherapy.

Stimuli-Responsive Polymersomes: Reshaping the Immunosuppressive Tumor Microenvironment

The progression of cancer involves mutations in normal cells, leading to uncontrolled division and tissue destruction, highlighting the complexity of tumor microenvironments (TMEs). Immunotherapy has emerged as a transformative approach, yet the balance between efficacy and safety remains a challenge. Nanoparticles such as polymersomes offer the possibility to precisely target tumors, deliver drugs in a controlled way, effectively modulate the antitumor immunity, and notably reduce side effects. Herein, stimuli-responsive polymersomes, with capabilities for carrying multiple therapeutics, are highlighted for their potential in enhancing antitumor immunity through mechanisms like inducing immunogenic cell death and activating STING (stimulator of interferon genes), etc. The recent progress of utilizing stimuli-responsive polymersomes to reshape the TME is reviewed here. The advantages and limitations to applied stimuli-responsive polymersomes are outlined. Additionally, challenges and future prospects in leveraging polymersomes for cancer therapy are discussed, emphasizing the need for future research and clinical translation.

A Triple-Responsive Polymeric Prodrug Nanoplatform with Extracellular ROS Consumption and Intracellular H2O2 Self-Generation for Imaging-Guided Tumor Chemo-Ferroptosis-Immunotherapy

High reactive oxygen species (ROS) levels in tumor microenvironment (TME) impair both immunogenic cell death (ICD) efficacy and T cell activity. Furthermore, tumor escapes immunosurveillance via programmed death-1/programmed death ligand-1 (PD-L1) signal, and the insufficient intracellular hydrogen peroxide weakens ferroptosis efficacy. To tackle the above issues, a glutathione (GSH)/ROS/pH triple-responsive prodrug nanomedicine that encapsulates Fe2O3 nanoparticle via electrostatic interaction is constructed for magnetic resonance imaging (MRI)-guided multi-mode theranostics with chemotherapy/ferroptosis/immunotherapy. The diselenide bond consumes ROS in TME to increase T cells and ICD efficacy, the cleavage of which facilitates PD-L1 antagonist D peptide release to block immune checkpoint. After intracellular internalization, Fe2O3 nanoparticle is released in the acidic endosome for MRI simultaneously with lipid peroxides generation for tumor ferroptosis. Doxorubicin is cleaved from polymers in the condition of high intracellular GSH level accompanied by tumor ICD, which simultaneously potentiates ferroptosis by NADPH oxidase mediated H2O2 self-generation. In vivo results indicate that the nanoplatform strengthens tumor ICD, induces cytotoxic T lymphocytes proliferation, inhibits 4T1 tumor regression and metastasis, and prolongs survival median. In all, a new strategy is proposed in strengthening ICD and T cells activity cascade with ferroptosis as well as immune checkpoint blockade for effective tumor immunotherapy.

Nanomedicine Remodels Tumor Microenvironment for Solid Tumor Immunotherapy

Although immunotherapy is relatively effective in treating hematological malignancies, their efficacy against solid tumors is still suboptimal or even noneffective presently. Compared to hematological cancers, solid tumors exhibit strikingly different immunosuppressive microenvironment, severely deteriorating the efficacy of immunotherapy: (1) chemical features such as hypoxia and mild acidity suppress the activity of immune cells, (2) the pro-tumorigenic domestication of immune cells in the microenvironment within the solid tumors further undermines the effectiveness of immunotherapy, and (3) the dense physical barrier of solid tumor tissues prevents the effective intratumoral infiltration and contact killing of active immune cells. Therefore, we believe that reversing the immunosuppressive microenvironment are of critical priority for the immunotherapy against solid tumors. Due to their unique morphologies, structures, and compositions, nanomedicines have become powerful tools for achieving this goal. In this Perspective, we will first briefly introduce the immunosuppressive microenvironment of solid tumors and then summarize the most recent progresses in nanomedicine-based immunotherapy for solid tumors by remodeling tumor immune-microenvironment in a comprehensive manner. It is highly expected that this Perspective will aid in advancing immunotherapy against solid tumors, and we are highly optimistic on the future development in this burgeoning field.

Polymersomes as Innovative, Stimuli-Responsive Platforms for Cancer Therapy

This review addresses the urgent need for more targeted and less toxic cancer treatments by exploring the potential of multi-responsive polymersomes. These advanced nanocarriers are engineered to deliver drugs precisely to tumor sites by responding to specific stimuli such as pH, temperature, light, hypoxia, and redox conditions, thereby minimizing the side effects associated with traditional chemotherapy. We discuss the design, synthesis, and recent applications of polymersomes, emphasizing their ability to improve therapeutic outcomes through controlled drug release and targeted delivery. Moreover, we highlight the critical areas for future research, including the optimization of polymersome-biological interactions and biocompatibility, to facilitate their clinical adoption. Multi-responsive polymersomes emerge as a promising development in nanomedicine, offering a pathway to safer and more effective cancer treatments.

Copper Increases the Sensitivity of Cholangiocarcinoma Cells to Tripterine by Inhibiting TMX2-Mediated Unfolded Protein Reaction Activation

Chemotherapy-induced adaptive resistance is a significant factor that contributes to low therapeutic efficacy in tumor cells. The unfolded protein response (UPR) is a key mechanism in the development of drug resistance and serves as a critical reactive system for endoplasmic reticulum stress. Cu(II) can reduce the abundance of 60S ribosomal subunits and inhibit rRNA processing, leading to a decrease in the translation efficiency of the GRP78/BiP mRNA, which serves as a primary sensor for UPR activation. In this study, CuET-Lipid@Cela, composed of CuET and tripterine (Cela), demonstrates a significant synergistic antitumor effect on cholangiocarcinoma (CCA) cells. RNA-Seq is used to investigate the underlying mechanism, which suggests that the transmembrane protein 2 (TMX2) gene may be crucial in Cu(II) regulation of UPR by inhibiting the activation of GRP78/BiP and PERK/eIF2α. The synergistic antitumor efficacy of CuET-Lipid@Cela via inhibition of TMX2 is also confirmed in a myrAKT/YapS127A plasmid-induced primary CCA mouse model, providing new insights into the reversal of acquired chemotherapy-induced resistance in CCA.