The abscopal effect: inducing immunogenicity in the treatment of brain metastases secondary to lung cancer and melanoma

Anti-PD-L1 blockade facilitates antitumor effects of radiofrequency ablation by improving tumor immune microenvironment in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a complex disease with advanced presentation that significantly affects survival rates. Therefore, novel therapeutic strategies are needed. In this study, we investigate the tumor microenvironment (TME) in HCC by analyzing 13 HCC samples at single cell level. We identified key cell populations, including CD8 + T cells, Tregs, M1/M2 macrophages, and CD4 + memory T cells, and explored their roles and interactions. Our research revealed an early enrichment of CD8 + T cells, which could potentially lead to their exhaustion and facilitate tumor progression. We also investigated the impact of percutaneous radiofrequency ablation (RFA) on the immune microenvironment. Using a dual tumor mouse model, we demonstrated that RFA induces necrosis, enhancing antigen presentation and altering immune responses. Our results indicate that RFA increases PD-L1 expression in residual liver tissue, suggesting potential immune escape mechanisms. Furthermore, the combination of RFA and anti-PD-L1 therapy in the mouse model resulted in significant improvements in immune modulation. This included increased CD8 + T cell efficacy and decreased Treg infiltration. This combination shows promise as an approach to counteract HCC progression by altering the immune landscape. This study highlights the critical interaction within the TME of HCC and suggests the possibility of improving patient outcomes by targeting immune evasion mechanisms through combined therapeutic strategies.

The immune landscape in brain metastasis

The prognosis for patients with brain metastasis remains dismal despite intensive therapy including surgical resection, radiotherapy, chemo-, targeted, and immunotherapy. Thus, there is a high medical need for new therapeutic options. Recent advances employing high-throughput and spatially resolved single-cell analyses have provided unprecedented insights into the composition and phenotypes of the diverse immune cells in the metastatic brain, revealing a unique immune landscape starkly different from that of primary brain tumors or other metastatic sites. This review summarizes the current evidence on the composition and phenotypes of the most prominent immune cells in the brain metastatic niche, along with their dynamic interactions with metastatic tumor cells and each other. As the most abundant immune cell types in this niche, we explore in detail the phenotypic heterogeneity and functional plasticity of tumor-associated macrophages, including both resident microglia and monocyte-derived macrophages, as well as the T-cell compartment. We also review preclinical and clinical trials evaluating the therapeutic potential of targeting the immune microenvironment in brain metastasis. Given the substantial evidence highlighting a significant role of the immune microenvironmental niche in brain metastasis pathogenesis, a comprehensive understanding of the key molecular and cellular factors within this niche holds great promise for developing novel therapeutic approaches as well as innovative combinatory treatment strategies for brain metastasis.

Enhanced Tumor Immunotherapy by Triple Amplification Effects of Nanomedicine on the STING Signaling Pathway in Dendritic Cells

Insufficient activation of stimulator of interferon genes (STING) signaling pathway in tumor-associated dendritic cells limits the efficiency of tumor immunotherapy. Herein, the "three-in-one" IAHA-LaP/siPTPN6 NPs containing lanthanum ions (La3+), cGAMP, and PTPN6 siRNA are developed for triple amplification of the STING pathway. In vitro results demonstrate that La3+ significantly promotes cGAMP-mediated activation of the STING pathway by enhancing the phosphorylation of STING, TBK1, IRF3, and NF-κB p65. Moreover, the IAHA-LaP/siPTPN6 NPs further significantly enhance the phosphorylation of STING and NF-κB p65 and augment K63-linked ubiquitination of STING protein via siPTPN6-mediated downregulation of SHP-1 protein. Furthermore, NPs improve the secretion of IFNβ (2.4-fold), IL-6 (1.5-fold), and TNF-α (1.4-fold), thereby promoting DCs maturation compared to the mixture of La3+ and cGAMP. In vivo results show that the IAHA-LaP/siPTPN6 NPs remarkably inhibit primary tumor growth by increasing the percentage of mature DCs in tumor-draining lymph nodes, polarizing M2/M1 phenotype in TME, and promoting the infiltration of CD8+T cells into tumors. Moreover, these NPs dramatically prevent the growth of distal tumor by inducing systemic anti-tumor immunity and generating a long-term anti-tumor memory for protection against tumor recurrence in mice bearing bilateral B16F10. These IAHA-LaP/siPTPN6 NPs may offer a promising platform for robust anti-tumor immune responses.

A combination of lymphatic drug delivery of anti-CTLA-4 antibody and local radiotherapy for solid-tumor treatment

The combination of radiotherapy and immunotherapy is a promising approach that has been shown in clinical trials to improve significantly survival and response rates compared with monotherapy against solid tumor. Since anti-CTLA-4 antibodies block immunosuppressive signals mainly in the lymph nodes (LNs), efficient drug delivery to the lymphatic system is desirable. However, the immune checkpoint inhibitors, especially anti-CTLA-4 are currently administered intravenously (i.v.), resulting in limited efficacy in controlling solid tumor and inhibiting metastases, and the method of administration has not been optimized. Here, we show that a combination of local radiotherapy and administration of anti-CTLA-4 antibodies using a lymphatic drug delivery system (LDDS) suppresses solid tumor and metastases. We compared the efficacy of LDDS-based immunotherapy or radioimmunotherapy with i.v. administration in a solid-tumor model created by subcutaneous inoculation into LN-swollen mice with osteosarcoma cells. Tumor-bearing mice were divided into various groups (no treatment, immunotherapy [i.v. or LDDS], radiotherapy, and radioimmunotherapy [i.v. or LDDS]) and were observed for 28 days. Immunotherapy was administered with a cumulative dose of 10 mg/kg of anti-CTLA-4 monoclonal antibody, and radiotherapy was administered with a cumulative 8 Gy of fractionated X-ray irradiation. For immunotherapy alone, LDDS provided slight tumor growth inhibition but did not inhibit distant metastasis. For radioimmunotherapy, however, tumor growth was delayed and distant metastasis was suppressed compared with radiotherapy alone. In particular, the LDDS group achieved a high tumor-suppressive effect with T cell-mediated immune activity, indicating the efficacy of LDDS in radioimmunotherapy.

Immunotherapy revolutionizing brain metastatic cancer treatment: personalized strategies for transformative outcomes

Brain metastatic cancer poses a significant clinical challenge, with limited treatment options and poor prognosis for patients. In recent years, immunotherapy has emerged as a promising strategy for addressing brain metastases, offering distinct advantages over conventional treatments. This review explores the evolving landscape of tumor immunotherapy in the context of brain metastatic cancer, focusing on the intricate interplay between the tumor microenvironment (TME) and immunotherapeutic approaches. By elucidating the complex interactions within the TME, including the role of immune cells, cytokines, and extracellular matrix components, this review highlights the potential of immunotherapy to reshape the treatment paradigm for brain metastases. Leveraging immune checkpoint inhibitors, cellular immunotherapies, and personalized treatment strategies, immunotherapy holds promise in overcoming the challenges posed by the blood-brain barrier and immunosuppressive microenvironment of brain metastases. Through a comprehensive analysis of current research findings and future directions, this review underscores the transformative impact of immunotherapy on the management of brain metastatic cancer, offering new insights and opportunities for personalized and precise therapeutic interventions.

Immunotherapy Combined with Radiation in Malignant Melanoma without BRAF Mutations Brain Metastases-Favorable Response after Immunotherapy Continued beyond Progression

We present the case of a patient who was diagnosed in 2018 with nodular Malignant Melanoma (MM) without BRAF V 600 mutations stage 3 C (pT4b pN1a M0), and who underwent adjuvant citokines treatment with Interferon alpha 2b-48 weeks. Immunotherapy was initiated in January 2021 for lung and lymph node metastases. In June 2021, there was a partial response of the lung and lymph node metastases, but there was also progression to brain metastases. Immunotherapy was continued and Whole Brain Radiotherapy (WBRT) was performed. In September 2023, the imaging investigations revealed a favorable response, with no lesions suggestive of secondary determinations. The combination of Radiotherapy (RT) and Immunotherapy (IT) with Immune Checkpoint Inhibitors (ICI) has an abscopal effect. There is a coordinated action in the combination of RT and IT in order to obtain a common result, with the antitumor effect being greater than if RT or IT acted separately.

Combination of radiosurgery and immunotherapy in brain metastases: balance between efficacy and toxicities

PURPOSE OF REVIEW

The incidence of brain metastasis is high and still increasing. Among local therapies, stereotactic radiosurgery (SRS) is an effective treatment option, optimally sparing normal brain, even for multiple brain metastases. Immune checkpoint inhibitors (ICIs) become the new standard of care in an increasing number of cancers, and the combination SRS and ICI is often proposed to patients, but few data have been published on the efficacy and the toxicity of this association.

RECENT FINDINGS

Explaining this lack of consensus: retrospective studies with different primary cancers, various treatment lines and unknown levels of steroid exposure. Concerning the toxicity, the independent association of radionecrosis with brain-PTV volume was confirmed, and a decreased dose of SRS is now tested in a randomized study. Finally, a 'concurrent' delivery of SRS and ICI (within a 4 weeks' interval) seems the optimal schedule; fractionated radiosurgery for large brain metastasis should be favored. Radio-sensitizing nanoparticles and devices aiming to increase the permeability of the blood brain barrier should be considered in future combinations.

SUMMARY

The efficacy/toxicity balance of SRS-ICI combination should be regularly re-evaluated, anticipating continued progress in ICI and SRS delivery, with more long-survivors potentially exposed to long-term toxicities. Patients should be included in clinical trials and clearly informed to participate more closely in the final choice.