A radioenhancing nanoparticle mediated immunoradiation improves survival and generates long-term antitumor immune memory in an anti-PD1-resistant murine lung cancer model

Enhancing X-Ray Sensitization with Multifunctional Nanoparticles

In the progression of X-ray-based radiotherapy for the treatment of cancer, the incorporation of nanoparticles (NPs) has a transformative impact. This study investigates the potential of NPs, particularly those comprised of high atomic number elements, as radiosensitizers. This aims to optimize localized radiation doses within tumors, thereby maximizing therapeutic efficacy while preserving surrounding tissues. The multifaceted applications of NPs in radiotherapy encompass collaborative interactions with chemotherapeutic, immunotherapeutic, and targeted pharmaceuticals, along with contributions to photodynamic/photothermal therapy, imaging enhancement, and the integration of artificial intelligence technology. Despite promising preclinical outcomes, the paper acknowledges challenges in the clinical translation of these findings. The conclusion maintains an optimistic stance, emphasizing ongoing trials and technological advancements that bolster personalized treatment approaches. The paper advocates for continuous research and clinical validation, envisioning the integration of NPs as a revolutionary paradigm in cancer therapy, ultimately enhancing patient outcomes.

Radiotherapy-activated NBTXR3 nanoparticles promote ferroptosis through induction of lysosomal membrane permeabilization

PURPOSE

Radiotherapy-activated NBTXR3 (NBTXR3 + RT) has demonstrated superior efficacy in cancer cell destruction and tumor growth control, compared to radiotherapy (RT), in preclinical and clinical settings. Previous studies highlighted the immunomodulatory properties of NBTXR3 + RT, such as modification of tumor cell immunogenicity/adjuvanticity, producing an effective local tumor control and abscopal effect, related to an enhanced antitumor immune response. Furthermore, NBTXR3 + RT has shown potential in restoring anti-PD1 efficacy in a refractory tumor model. However, the early events leading to these results, such as NBTXR3 endocytosis, intracellular trafficking and primary biological responses induced by NBTXR3 + RT remain poorly understood.

METHODS

We analyzed by transmission electron microscopy endocytosis and intracellular localization of NBTXR3 nanoparticles after endocytosis in various cell lines, in vitro and in vivo. A kinetic of NBTXR3 endocytosis and its impact on lysosomes was conducted using LysoTracker staining, and a RNAseq analysis was performed. We investigated the ability of NBTXR3 + RT to induce lysosomal membrane permeabilization (LMP) and ferroptosis by analyzing lipid peroxidation. Additionally, we evaluated the recapture by cancer cells of NBTXR3 released from dead cells.

RESULTS

NBTXR3 nanoparticles were rapidly internalized by cells mainly through macropinocytosis and in a less extend by clathrin-dependent endocytosis. NBTXR3-containing endosomes were then fused with lysosomes. The day following NBTXR3 addition, we measured a significant increase in LysoTracker lysosome labeling intensity, in vitro as in vivo. Following RT, a significant lysosomal membrane permeabilization (LMP) was measured exclusively in cells treated with NBTXR3 + RT, while RT had no effect. The day post-irradiation, a significant increase in lipid peroxidation, a biomarker of ferroptosis, was measured with NBTXR3 + RT compared to RT. Moreover, we demonstrated that NBTXR3 nanoparticles released from dead cells can be recaptured by cancer cells.

CONCLUSIONS

Our findings provide novel insights into the early and specific biological effects induced by NBTXR3 + RT, especially LMP, not induced by RT in our models. The subsequent significant increase in lipid peroxidation partially explains the enhanced cancer cell killing capacity of NBTXR3 + RT compared to RT, potentially by promoting ferroptosis. This study improves our understanding of the cellular mechanisms underlying NBTXR3 + RT and highlights its potential as an agnostic therapeutic strategy for solid cancers treatment.

Nanotechnology-enhanced radiotherapy and the abscopal effect: Current status and challenges of nanomaterial-based radio-immunotherapy

Rare but consistent reports of abscopal remission in patients challenge the notion that radiotherapy (RT) is a local treatment; radiation-induced cancer cell death can trigger activation and recruitment of dendritic cells to the primary tumor site, which subsequently initiates systemic immune responses against metastatic lesions. Although this abscopal effect was initially considered an anomaly, combining RT with immune checkpoint inhibitor therapies has been shown to greatly improve the incidence of abscopal responses via modulation of the immunosuppressive tumor microenvironment. Preclinical studies have demonstrated that nanomaterials can further improve the reliability and potency of the abscopal effect for various different types of cancer by (1) altering the cell death process to be more immunogenic, (2) facilitating the capture and transfer of tumor antigens from the site of cancer cell death to antigen-presenting cells, and (3) co-delivering immune checkpoint inhibitors along with radio-enhancing agents. Several unanswered questions remain concerning the exact mechanisms of action for nanomaterial-enhanced RT and for its combination with immune checkpoint inhibition and other immunostimulatory treatments in clinically relevant settings. The purpose of this article is to summarize key recent developments in this field and also highlight knowledge gaps that exist in this field. An improved mechanistic understanding will be critical for clinical translation of nanomaterials for advanced radio-immunotherapy. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Radiation-activated nanoparticles: Which combination to optimize radiosensitization?

Radiotherapy plays a crucial role in the treatment of various cancers. With the ongoing technological advancements in radiotherapy equipment, allowing for increasingly precise targeting of tumours, there are numerous strategies being explored to enhance its effectiveness by combining it with other therapies. Among these, metal nanoparticles seem to have a promising future driven by their ability to locally amplify the dose deposited by ionizing radiation, and to radiosensitize cells by modifying their oxidative status. Recent advancements in understanding the mechanisms of action of these nanoparticles have provided valuable insights for the development of new therapeutic combinations. Among these, the combination with immunotherapies would make it possible to benefit both from the amplified local effect of radiotherapy by nanoparticles and to induce a better antitumour immune response. In this article, we review shortly the existing literature on ongoing combinations and suggest potential novel therapies associated with the combination of radiotherapy and nanoparticles.

Harnessing Hafnium-Based Nanomaterials for Cancer Diagnosis and Therapy

With the rapid development of nanotechnology and nanomedicine, there are great interests in employing nanomaterials to improve the efficiency of disease diagnosis and treatment. The clinical translation of hafnium oxide (HfO2 ), commercially namedas NBTXR3, as a new kind of nanoradiosensitizer for radiotherapy (RT) of cancers has aroused extensive interest in researches on Hf-based nanomaterials for biomedical application. In the past 20 years, Hf-based nanomaterials have emerged as potential and important nanomedicine for computed tomography (CT)-involved bioimaging and RT-associated cancer treatment due to their excellent electronic structures and intrinsic physiochemical properties. In this review, a bibliometric analysis method is employed to summarize the progress on the synthesis technology of various Hf-based nanomaterials, including HfO2 , HfO2 -based compounds, and Hf-organic ligand coordination hybrids, such as metal-organic frameworks or nanoscaled coordination polymers. Moreover, current states in the application of Hf-based CT-involved contrasts for tissue imaging or cancer diagnosis are reviewed in detail. Importantly, the recent advances in Hf-based nanomaterials-mediated radiosensitization and synergistic RT with other current mainstream treatments are also generalized. Finally, current challenges and future perspectives of Hf-based nanomaterials with a view to maximize their great potential in the research of translational medicine are also discussed.

Nanoparticle-enhanced proton beam immunoradiotherapy drives immune activation and durable tumor rejection

The combination of radiation therapy (RT) and immunotherapy has emerged as a promising treatment option in oncology. Historically, x-ray radiation (XRT) has been the most commonly used form of RT. However, proton beam therapy (PBT) is gaining recognition as a viable alternative, as it has been shown to produce similar outcomes to XRT while minimizing off-target effects. The effects of PBT on the antitumor immune response have only just begun to be described, and to our knowledge no studies to date have examined the effect of PBT as part of a combinatorial immunoradiotherapeutic strategy. Here, using a 2-tumor model of lung cancer in mice, we show that PBT in tandem with an anti-PD1 antibody substantially reduced growth in both irradiated and unirradiated tumors. This was accompanied by robust activation of the immune response, as evidenced by whole-tumor and single-cell RNA sequencing showing upregulation of a multitude of immune-related transcripts. This response was further significantly enhanced by the injection of the tumor to be irradiated with NBTXR3 nanoparticles. Tumors of mice treated with the triple combination exhibited increased infiltration and activation of cytotoxic immune cells. This triple combination eradicated both tumors in 37.5% of the treated mice and showed robust long-term immunity to cancer.

The artificial intelligence and machine learning in lung cancer immunotherapy

Since the past decades, more lung cancer patients have been experiencing lasting benefits from immunotherapy. It is imperative to accurately and intelligently select appropriate patients for immunotherapy or predict the immunotherapy efficacy. In recent years, machine learning (ML)-based artificial intelligence (AI) was developed in the area of medical-industrial convergence. AI can help model and predict medical information. A growing number of studies have combined radiology, pathology, genomics, proteomics data in order to predict the expression levels of programmed death-ligand 1 (PD-L1), tumor mutation burden (TMB) and tumor microenvironment (TME) in cancer patients or predict the likelihood of immunotherapy benefits and side effects. Finally, with the advancement of AI and ML, it is believed that "digital biopsy" can replace the traditional single assessment method to benefit more cancer patients and help clinical decision-making in the future. In this review, the applications of AI in PD-L1/TMB prediction, TME prediction and lung cancer immunotherapy are discussed.

Application of nano-radiosensitizers in combination cancer therapy

Radiosensitizers are compounds or nanostructures, which can improve the efficiency of ionizing radiation to kill cells. Radiosensitization increases the susceptibility of cancer cells to radiation-induced killing, while simultaneously reducing the potentially damaging effect on the cellular structure and function of the surrounding healthy tissues. Therefore, radiosensitizers are therapeutic agents used to boost the effectiveness of radiation treatment. The complexity and heterogeneity of cancer, and the multifactorial nature of its pathophysiology has led to many approaches to treatment. The effectiveness of each approach has been proven to some extent, but no definitive treatment to eradicate cancer has been discovered. The current review discusses a broad range of nano-radiosensitizers, summarizing possible combinations of radiosensitizing NPs with several other types of cancer therapy options, focusing on the benefits and drawbacks, challenges, and future prospects.

Radiation therapy-activated nanoparticle and immunotherapy: The next milestone in oncology?

Radiotherapy (RT) is a fundamental treatment at the locoregional or oligometastatic stages of cancer. In various tumors, RT effects may be optimized using synergistic combinations that enhance tumor response. Innovative strategies have been designed that explore the radiation mechanisms, at the physical, chemical and biological levels, to propose precision RT approaches. They consist in combining RT with immunotherapy to revert radiation immunosuppressive effects or to enhance radiation-induced immune defenses against the tumor to favor immunogenic cell death. Radiotherapy-activated nanoparticles are another innovation. By increasing radiation response in situ, nanoparticles improve tumor control locally, and can trigger systemic immune reactions that may be exploited to improve the systemic efficacy of RT. Strong clinical evidence of improved outcomes is now available for combinations of RT and immunotherapy on one hand and RT and nanoparticles on the other hand. The triple combination of RT, immunotherapy and nanoparticles is promising in terms of tolerance, local and systemic anti-tumor control. Yet, significant challenges remain to unravel the complexity of the multiscale mechanisms underlying response to this combination and their associated parameters. Such parameters include patient characteristics, tumor bulk and histology, radiation technique, energy, dose, fractionation, immunotherapy targets and predictive biomarkers, nanoparticle type, size, delivery (intratumoral/intravenous), distribution. The temporal combination is another critical parameter. The mechanisms of response of the combinatorial approaches are reviewed, with a focus on underlying mechanisms based on preclinical, translational and clinical studies. Opportunities for translation of current understanding into precision RT trials combined with immunotherapy and nanoparticles are also discussed.

The RadScopal Technique as an Immune Adjuvant to Treat Cancer

Since the momentous discovery of X-rays, high-dose radiotherapy (H-XRT) has been a cornerstone for combating cancer. The high-energy electromagnetic waves induce direct damage to tumor-cells’ DNA, thereby halting cell growth and proliferation, and eventually leading to tumor eradication. Furthermore, recent evidence suggests that H-XRT may have immunomodulatory properties which arise from its ability to induce the release of neoantigens, which in turn prime T-cells and contribute to T-cell repertoire diversity. Throughout the years, there have been different treatment modalities introduced as complements to H-XRT that have yielded greater results than monotherapy alone. In this review, we will discuss preclinical and clinical data related to the recently introduced low-dose radiotherapy (L-XRT) modality. We will also explore the justification for combining L-XRT and H-XRT, which became known as the “RadScopal Technique”, as a novel immune adjuvant to treat cancer. In this analysis, we detail and dissect the physiological mechanisms of action of each modality and describe the synergistic amalgamation effect observed on primary and metastatic tumors. Finally, we will explore the impetus for further studies to investigate combinations of the “RadScopal Technique” with various immune-oncology drug candidates.

Nanoparticles overcome adaptive immune resistance and enhance immunotherapy via targeting tumor microenvironment in lung cancer

Lung cancer is one of the common malignant cancers worldwide. Immune checkpoint inhibitor (ICI) therapy has improved survival of lung cancer patients. However, ICI therapy leads to adaptive immune resistance and displays resistance to PD-1/PD-L1 blockade in lung cancer, leading to less immune response of lung cancer patients. Tumor microenvironment (TME) is an integral tumor microenvironment, which is involved in immunotherapy resistance. Nanomedicine has been used to enhance the immunotherapy in lung cancer. In this review article, we described the association between TME and immunotherapy in lung cancer. We also highlighted the importance of TME in immunotherapy in lung cancer. Moreover, we discussed how nanoparticles are involved in regulation of TME to improve the efficacy of immunotherapy, including Nanomedicine SGT-53, AZD1080, Nanomodulator NRF2, Cisplatin nanoparticles, Au@PG, DPAICP@ME, SPIO NP@M-P, NBTXR3 nanoparticles, ARAC nanoparticles, Nano-DOX, MS NPs, Nab-paclitaxel, GNPs-hPD-L1 siRNA. Furthermore, we concluded that targeting TME by nanoparticles could be helpful to overcome resistance to PD-1/PD-L1 blockade in lung cancer.

NBTXR3 improves the efficacy of immunoradiotherapy combining nonfucosylated anti-CTLA4 in an anti-PD1 resistant lung cancer model

The efficacy of immunoradiotherapy consisting of radiation therapy and immune checkpoint blockade relies on effectively promoting the systemic antitumor immune response's activation while simultaneously reducing local factors favoring immune suppression. We previously demonstrated that NBTXR3, a nanoparticle radioenhancer, significantly improved immune responses in a murine anti-PD1-resistant metastatic lung cancer model. We hypothesize that radioactivated-NBTXR3 addition to anti-PD1 and a second-generation anti-CTLA4 could improve treatment effectiveness. To test this hypothesis, we inoculated mice with 344SQR cells in the right and left legs to establish primary and secondary tumors. The primary tumors were intratumorally injected with NBTXR3 nanoparticles on day 7, followed by three fractions of 12 Gy radiation on days 8, 9, and 10. The secondary tumors received two fractions of 1Gy radiation on days 13 and 14. Multiple rounds of anti-PD1, anti-CTLA4 or nonfucosylated anti-CTLA4 were given to the mice. Immune profiling of the tumors revealed that the combination of NBTXR3 with immunoradiotherapy significantly upregulated the activities of a wide range of antitumor immune pathways and reduced the abundance of regulatory suppressor T cells. This combination effectively eradicated the primary and secondary tumors and increased animal survival to 75%. Remarkably, previously treated with NBTXR3-containing treatment, the survivor mice exhibited a long-lasting antitumor memory immune response. This data provides compelling evidence of the efficacy of NBTXR3 to synergize with the immunoradiotherapy approach when combined with an anti-PD1 and multiple checkpoints such as a second generation anti-CTLA4 and show the potential for clinical uses of antitumor immunomodulatory effects of NBTXR3.

Combining a nanoparticle-mediated immunoradiotherapy with dual blockade of LAG3 and TIGIT improves the treatment efficacy in anti-PD1 resistant lung cancer

BACKGROUND

While improvements in immunoradiotherapy have significantly improved outcomes for cancer patients, this treatment approach has nevertheless proven ineffective at controlling the majority of malignancies. One of the mechanisms of resistance to immunoradiotherapy is that immune cells may be suppressed via the myriad of different immune checkpoint receptors. Therefore, simultaneous blockade of multiple immune checkpoint receptors may enhance the treatment efficacy of immunoradiotherapy.

METHODS

We combined NBTXR3-enhanced localized radiation with the simultaneous blockade of three different checkpoint receptors: PD1, LAG3, and TIGIT, and tested the treatment efficacy in an anti-PD1-resistant lung cancer model in mice. 129 Sv/Ev mice were inoculated with fifty thousand αPD1-resistant 344SQR cells in the right leg on day 0 to establish primary tumors and with the same number of cells in the left leg on day 4 to establish the secondary tumors. NBTXR3 was intratumorally injected into the primary tumors on day 7, which were irradiated with 12 Gy on days 8, 9, and 10. Anti-PD1 (200 µg), αLAG3 (200 µg), and αTIGIT (200 µg) were given to mice by intraperitoneal injections on days 5, 8, 11, 14, 21, 28, 35, and 42.

RESULTS

This nanoparticle-mediated combination therapy is effective at controlling the growth of irradiated and distant unirradiated tumors, enhancing animal survival, and is the only one that led to the destruction of both tumors in approximately 30% of the treated mice. Corresponding with this improved response is robust activation of the immune response, as manifested by increased numbers of immune cells along with a transcriptional signature of both innate and adaptive immunity within the tumor. Furthermore, mice treated with this combinatorial therapy display immunological memory response when rechallenged by the same cancer cells, preventing tumor engraftment.

CONCLUSION

Our results strongly attest to the efficacy and validity of combining nanoparticle-enhanced radiotherapy and simultaneous blockade of multiple immune checkpoint receptors and provide a pre-clinical rationale for investigating its translation into human patients.

A ‘Hybrid’ Radiotherapy Regimen Designed for Immunomodulation: Combining High-Dose Radiotherapy with Low-Dose Radiotherapy

Simple Summary

Radiotherapy is an important cancer treatment. Aside from its direct killing effect, it also affects anti-tumor immunity. However, radiotherapy’s immune effect is not clear; it depends on the dose and fraction, cancer type, combined immunotherapy, and many other factors. Studies have focused on the optimal radiotherapy regimen to stimulate anti-tumor immunity, but conflicts exist, especially regarding the best radiation dose and fractions. Interestingly, high-dose radiotherapy and low-dose radiotherapy have complementary effects on stimulating anti-tumor immunity. Preclinical studies supporting this finding have accumulated, but gaps between theory and clinical practice still exist. This review summarizes the evidence supporting the use of this ‘hybrid’ radiotherapy approach to effectively stimulate anti-tumor immunity, explains the immune mechanisms of this combination, raises questions that must be addressed in clinical practice, and provides ideas for designing individualized treatment to increase efficiency in stimulating anti-tumor immunity using high-dose plus low-dose radiotherapy.

Abstract

Radiotherapy (RT) affects anti-tumor immunity. However, the exact impact of RT on anti-tumor immune response differs among cancer types, RT dose and fractions, patients’ innate immunity, and many other factors. There are conflicting findings on the optimal radiation dose and fractions to stimulate effective anti-tumor immunity. High-dose radiotherapy (HDRT) acts in the same way as a double-edged sword in stimulating anti-tumor immunity, while low-dose radiotherapy (LDRT) seems to play a vital role in modulating the tumor immune microenvironment. Recent preclinical data suggest that a ‘hybrid’ radiotherapy regimen, which refers to combining HDRT with LDRT, can reap the advantages of both. Clinical data have also indicated a promising potential. However, there are still questions to be addressed in order to put this novel combination therapy into clinical practice. For example, the selection of treatment site, treatment volume, the sequencing of high-dose radiotherapy and low-dose radiotherapy, combined immunotherapy, and so on. This review summarizes the current evidence supporting the use of HDRT + LDRT, explains possible immune biology mechanisms of this ‘hybrid’ radiotherapy, raises questions to be considered when working out individualized treatment plans, and lists possible avenues to increase efficiency in stimulating anti-tumor immunity using high-dose plus low-dose radiotherapy.