Alterations in Immune Response Profile of Tumor-Draining Lymph Nodes after High-Intensity Focused Ultrasound Ablation of Breast Cancer Patients

Ultrasound-Based Micro-/Nanosystems for Biomedical Applications

Due to the intrinsic non-invasive nature, cost-effectiveness, high safety, and real-time capabilities, besides diagnostic imaging, ultrasound as a typical mechanical wave has been extensively developed as a physical tool for versatile biomedical applications. Especially, the prosperity of nanotechnology and nanomedicine invigorates the landscape of ultrasound-based medicine. The unprecedented surge in research enthusiasm and dedicated efforts have led to a mass of multifunctional micro-/nanosystems being applied in ultrasound biomedicine, facilitating precise diagnosis, effective treatment, and personalized theranostics. The effective deployment of versatile ultrasound-based micro-/nanosystems in biomedical applications is rooted in a profound understanding of the relationship among composition, structure, property, bioactivity, application, and performance. In this comprehensive review, we elaborate on the general principles regarding the design, synthesis, functionalization, and optimization of ultrasound-based micro-/nanosystems for abundant biomedical applications. In particular, recent advancements in ultrasound-based micro-/nanosystems for diagnostic imaging are meticulously summarized. Furthermore, we systematically elucidate state-of-the-art studies concerning recent progress in ultrasound-based micro-/nanosystems for therapeutic applications targeting various pathological abnormalities including cancer, bacterial infection, brain diseases, cardiovascular diseases, and metabolic diseases. Finally, we conclude and provide an outlook on this research field with an in-depth discussion of the challenges faced and future developments for further extensive clinical translation and application.

Recent advances of ultrasound-responsive nanosystems in tumor immunotherapy

Immunotherapy has revolutionized cancer treatment by boosting the immune system and preventing disease escape mechanisms. Despite its potential, challenges like limited response rates and adverse immune effects impede its widespread clinical adoption. Ultrasound (US), known for its safety and effectiveness in tumor diagnosis and therapy, has been shown to significantly enhance immunotherapy when used with nanosystems. High-intensity focused ultrasound (HIFU) can obliterate tumor cells and elicit immune reactions through the creation of immunogenic debris. Low-intensity focused ultrasound (LIFU) bolsters tumor immunosuppression and mitigates metastasis risk by concentrating dendritic cells. Ultrasonic cavitation (UC) produces microbubbles that can transport immune enhancers directly, thus strengthening the immune response and therapeutic impact. Sonodynamic therapy (SDT) merges nanotechnology with immunotherapy, using specialized sonosensitizers to kill cancer cells and stimulate immune responses, increasing treatment success. This review discusses the integration of ultrasound-responsive nanosystems in tumor immunotherapy, exploring future opportunities and current hurdles.

Experimental study of HIFU incomplete ablation on the damage effect and prognosis of rabbit VX2 breast cancer model

PURPOSE

High-intensity focused ultrasound (HIFU) represents an emerging noninvasive modality for tumor treatment. While biological responses and immunological change associated with incomplete ablation have not been thoroughly investigated. This study aims to evaluate the damage effect of HIFU incomplete ablation via establishing animal model and further explore its possible mechanism to inhibit tumor growth.

METHODS

The rabbit VX2 breast cancer model was established and received HIFU treatment with complete ablation (100% tumor volume) and incomplete ablation (about 80% tumor volume) under real-time B-ultrasound monitoring. Histopathological alterations, dynamics of tumor cell apoptosis and proliferation, expression levels of VEGF, MMP-9, IL-2R, TGF-β1, HSP-70, IL-6, IL-8, and INF-γ, and the presence of circulating tumor cells (CTCs) were evaluated post-HIFU incomplete ablation.

RESULTS

For HIFU 80% ablation group, there was an 85.85% reduction in tumor volume 21 days post-intervention. A marked increase in tumor cell apoptosis and a concomitant decrease in proliferation were observed. Notably, distant tumor metastasis rates, CTC counts, and expression levels of VEGF, MMP-9, IL-2R, TGF-β1, IL-6, and IL-8 were significantly reduced. In contrast, INF-γ and HSP-70 expressions were notably elevated, aligning with findings from the 100% ablation group.

CONCLUSIONS

HIFU incomplete ablation, with an 80% tumor ablation rate, induces substantial tumor damage, augments tumor cell apoptosis, and triggers an anti-tumor immune response, curtailing metastasis. These insights may underpin further investigations into the therapeutic implications of HIFU incomplete ablation.

Immune checkpoint inhibition: a future guided by radiology

The limitation of the function of antitumour immune cells is a common hallmark of cancers that enables their survival. As such, the potential of immune checkpoint inhibition (ICI) acts as a paradigm shift in the treatment of a range of cancers but has not yet been fully capitalised. Combining minimally and non-invasive locoregional therapies offered by radiologists with ICI is now an active field of research with the aim of furthering therapeutic capabilities in medical oncology. In parallel to this impending advancement, the "imaging toolbox" available to radiologists is also growing, enabling more refined tumour characterisation as well as greater accuracy in evaluating responses to therapy. Options range from metabolite labelling to cellular localisation to immune checkpoint screening. It is foreseeable that these novel imaging techniques will be integrated into personalised treatment algorithms. This growth in the field must include updating the current standardised imaging criteria to ensure they are fit for purpose. Such criteria is crucial to both appropriately guide clinical decision-making regarding next steps of treatment, but also provide reliable prognosis. Quantitative approaches to these novel imaging techniques are also already being investigated to further optimise personalised therapeutic decision-making. The therapeutic potential of specific ICIs and locoregional therapies could be determined before administration thus limiting unnecessary side-effects whilst maintaining efficacy. Several radiological aspects of oncological care are advancing simultaneously. Therefore, it is essential that each development is assessed for clinical use and optimised to ensure the best treatment decisions are being offered to the patient. In this review, we discuss state of the art advances in novel functional imaging techniques in the field of immuno-oncology both pre-clinically and clinically.

Immunomodulation and targeted drug delivery with high intensity focused ultrasound (HIFU): Principles and mechanisms

High intensity focused ultrasound (HIFU) is a non-invasive and non-ionizing sonic energy-based therapeutic technology for inducing thermal and non-thermal effects in tissues. Depending on the parameters, HIFU can ablate tissues by heating them to >55 °C to induce denaturation and coagulative necrosis, improve radio- and chemo-sensitizations and local drug delivery from nanoparticles at moderate hyperthermia (~41-43 °C), and mechanically fragment cells using acoustic cavitation (also known as histotripsy). HIFU has already emerged as an attractive modality for treating human prostate cancer, veterinary cancers, and neuromodulation. Herein, we comprehensively review the role of HIFU in enhancing drug delivery and immunotherapy in soft and calcified tissues. Specifically, the ability of HIFU to improve adjuvant treatments from various classes of drugs is described. These crucial insights highlight the opportunities and challenges of HIFU technology and its potential to support new clinical trials and translation to patients.

Mechanical destruction using a minimally invasive Ultrasound Needle induces anti-tumor immune responses and synergizes with the anti-PD-L1 blockade

Immune checkpoint inhibitors (ICIs) have been widely used in treating various tumors; however, the objective response rate of ICIs is less than 40%. In this study, we attempted to induce anti-tumor immune responses using an improved ultrasonic horn device, Ultrasound Needle (UN). We tested its synergistic anti-tumor efficacy with an anti-PD-L1 antibody in a mouse tumor model. Under different parameters, UN treatment selectively induced mechanical destruction and thermal ablation effects on tumor tissues. The mechanical destruction effect of UN treatment increased the infiltration of CD8⁺ T cells in tumors and relieved the immunosuppressive tumor microenvironment. It also induced systemic anti-tumor immune responses and enhanced the therapeutic efficacy of the anti-PD-L1 antibody in both local and abscopal tumors. The mechanical destruction effect of UN treatment resulted in the release of damage-associated molecular patterns and promoted dendritic cells (DCs)-based antigen presentation. Depletion of DCs or CD8⁺ T cells eliminated the anti-tumor immune responses induced by UN treatment and weakened the synergistic anti-tumor efficacy with anti-PD-L1 antibody. Therefore, minimally invasive UN may provide a new therapeutic modality for ultrasound-assisted immunotherapy.

Combination of Focused Ultrasound, Immunotherapy, and Chemotherapy: New Perspectives in Breast Cancer Therapy

Focused ultrasound is a treatment modality increasingly used for diverse therapeutic applications, and currently approved for several indications, including prostate cancers and uterine fibroids. But what about breast cancer? Breast cancer is the most common and deadliest cancer in women worldwide. While there are different treatment strategies available, there is a need for development of more effective and personalized modalities, with fewer side effects. Therapeutic ultrasound is such an option, and this review summarizes the state of the art in their use for the treatment of breast cancer and evaluate potentials of novel treatment approaches combining therapeutic ultrasound, immuno- and chemo-therapies.

Ablative Therapies for Breast Cancer: State of Art

Breast cancer (BC) is the most frequently diagnosed malignancy among women. In the past two decades, new technologies and BC screening have led to the diagnosis of smaller and earlier-stage BC (ESBC). Therefore, percutaneous minimally invasive techniques (PMIT) were adopted to treat patients unfit for surgery, women who refuse it, or elderly patients with comorbidities that could make surgery a difficult and life-threatening treatment. The target of PMIT is small-size ESBC with the scope of obtaining similar efficacy as surgery. Minimally invasive treatments are convenient alternatives with promising effectiveness, lower morbidity, less cost, less scarring and pain, and more satisfying cosmetic results. Ablative techniques used in BC are cryoablation, radiofrequency ablation, microwave ablation, high-intensity focused ultrasound (US), and laser ablation. The aim of our study is to discuss the current status of percutaneous management of BC, evaluate the clinical outcomes of PMIT in BC, and analyze future perspectives regarding ablation therapy in BC.

Rational Nanomedicine Design Enhances Clinically Physical Treatment-Inspired or Combined Immunotherapy

Independent of tumor type and non-invasive or minimally-invasive feature, current physical treatments including ultrasound therapy, microwave ablation (MWA), and radiofrequency ablation (RFA) are widely used as the local treatment methods in clinics for directly killing tumors and activating systematic immune responses. However, the activated immune responses are inadequate and incompetent for tumor recession, and the incomplete thermal ablation even aggravates the immunosuppressive tumor microenvironment (ITM), resulting in the intractable tumor recurrence and metastasis. Intriguingly, nanomedicine provides a powerful platform as they can elevate energy utilization efficiency and augment oncolytic effects for mitigating ITM and potentiating the systematic immune responses. Especially after combining with clinical immunotherapy, the anti-tumor killing effect by activating or enhancing the human anti-tumor immune system is reached, enabling the effective prevention against tumor recurrence and metastasis. This review systematically introduces the cutting-edge progress and direction of nanobiotechnologies and their corresponding nanomaterials. Moreover, the enhanced physical treatment efficiency against tumor progression, relapse, and metastasis via activating or potentiating the autologous immunity or combining with exogenous immunotherapeutic agents is exemplified, and their rationales are analyzed. This review offers general guidance or directions to enhance clinical physical treatment from the perspectives of immunity activation or magnification.

How Compatible Are Immune Checkpoint Inhibitors and Thermal Ablation for Liver Metastases?

Simple Summary

Although immune checkpoint inhibitors (ICIs) have achieved great progression in cancer treatment, the efficacy of ICI monotherapy is still limited. Meanwhile, the negative efficacy of thermal ablation for liver metastases is the high rate of local tumor progression. Since thermal ablation-induced inflammation and increases in tumor antigens have been suggested to promote the cancer-immunity cycle, thermal ablation and ICI can boost the immune response against cancer cells as one of the positive synergy effects. The findings of preclinical and clinical research have provided supportive evidence for the combination of ICIs with thermal ablation reversing T-cell exhaustion and demonstrating synergy. However, the clinical feasibility of immune response activation by combination therapy with ICI monotherapy and thermal ablation appears to be limited, it may be not very common phenomena.

Abstract

Cancer immunotherapy, which reactivates the weakened immune cells of cancer patients, has achieved great success, and several immune checkpoint inhibitors (ICIs) are now available in clinical practice. Despite promising clinical outcomes, favorable responses are only observed in a fraction of patients, and resistance mechanisms, including the absence of tumor antigens, have been reported. Thermal ablation involves the induction of irreversible damage to cancer cells by localized heat and may result in the release of tumor antigens. The combination of immunotherapy and thermal ablation is an emerging therapeutic option with enhanced efficacy. Since thermal ablation-induced inflammation and increases in tumor antigens have been suggested to promote the cancer-immunity cycle, the combination of immuno-oncology (IO) therapy and thermal ablation may be mutually beneficial. In preclinical and clinical studies, the combination of ICI and thermal ablation significantly inhibited tumor growth, and synergistic antitumor effects appeared to prolong the survival of patients with secondary liver cancer. However, evidence for the efficacy of ICI monotherapy combined with thermal ablation is currently insufficient. Therefore, the clinical feasibility of immune response activation by ICI monotherapy combined with thermal ablation may be limited, and thermal ablation may be more compatible with dual ICIs (the IO–IO combination) to induce strong immune responses.

Bubble-Assisted HIFU Ablation Enabled by Calcium Peroxide

High intensity focused ultrasound (HIFU), as one of the most advanced and preferred cancer treatment modes, has shown great promise due to its minimal invasiveness and irradiation-free feature. However, a...