Anti-PD-1/anti-CTLA-4 efficacy in melanoma brain metastases depends on extracranial disease and augmentation of CD8+ T cell trafficking

Dual implication of endothelial adhesion molecules in tumor progression and cancer immunity

Adhesion molecules are proteins expressed at the surface of various cell types. Their main contribution to immunity is to allow the infiltration of immune cells in an inflamed site. In cancer, adhesion molecules have been shown to promote tumor dissemination favoring the development of metastasis. While adhesion molecule inhibition approaches were unsuccessful for cancer control, their importance for the generation of an immune response alone or in combination with immunotherapies has gained interest over the past years. Currently, the balance of adhesion molecules for tumor promotion/inhibition is unclear. Here we review the role of selectins, intercellular adhesion molecules (ICAM) and vascular cell adhesion molecules (VCAM) from the perspective of the dual contribution of adhesion molecules in tumor progression and immunity.

Cemiplimab monotherapy as first-line treatment of patients with brain metastases from advanced non-small cell lung cancer with programmed cell death-ligand 1 ≥50

BACKGROUND

In the phase 3 EMPOWER-Lung 1 study, first-line cemiplimab monotherapy provided significant survival benefit versus chemotherapy in patients with advanced non-small cell lung cancer (NSCLC) with programmed cell death-ligand 1 (PD-L1) ≥50%. This exploratory subgroup analysis investigated the clinical outcomes of cemiplimab treatment in patients with advanced NSCLC with brain metastases.

METHODS

Patients with advanced NSCLC were randomized (1:1) to cemiplimab 350 mg every 3 weeks or four cycles of platinum doublet chemotherapy (NCT03088540). Patients with symptomatic radiotherapy-treated brain metastases were eligible to enroll. Of the 565 patients with confirmed PD-L1 expression ≥50%, 69 (12%) had brain metastases at baseline.

RESULTS

Patients with brain metastases who received cemiplimab had a median overall survival (OS) of 52.4 months compared with 20.7 months for those who received chemotherapy (hazard ratio [HR], 0.40; p = .0031) and a median progression-free survival (PFS) of 12.5 versus 5.3 months (HR, 0.33; p = .0002), respectively. Patients without brain metastases had a median OS of 24.3 months with cemiplimab versus 12.5 months with chemotherapy (HR, 0.63; p < .0001); their median PFS was 6.5 months versus 5.2 months (HR, 0.55; p < .0001), respectively. Cemiplimab was associated with a significant improvement in global health status/quality of life in all patients, including those with brain metastases. The cemiplimab safety profile was generally similar in all patients.

CONCLUSIONS

In patients with advanced NSCLC with PD-L1 ≥50%, first-line cemiplimab monotherapy improved survival and patient-reported outcomes over chemotherapy for those who received prior radiotherapy for symptomatic brain metastases.

CCL2 blockade combined with PD-1/P-selectin immunomodulators impedes breast cancer brain metastasis

Over the last two decades, the diagnosis and treatment of breast cancer patients have improved considerably. However, brain metastases remain a major clinical challenge and a leading cause of mortality. Thus, a better understanding of the pathways involved in the metastatic cascade is essential. To this end, we have investigated the reciprocal effects of astrocytes and breast cancer cells, employing traditional 2D cell culture and our unique 3D multicellular tumouroid models. Our findings revealed that astrocytes enhance the proliferation, migration and invasion of breast cancer cells, suggesting a supportive role for astrocytes in breast cancer outgrowth to the brain. Elucidating the key players in astrocyte-breast cancer cells crosstalk, we found that CCL2 is highly expressed in breast cancer brain metastases tissue sections from both patients and mice. Our in vitro and in vivo models further confirmed that CCL2 has a functional role in brain metastasis. Given their aggressive nature, we sought additional immune checkpoints for rationale combination therapy. Among the promising candidates were the adhesion molecule P-selectin, which we have recently shown to play a key role in the crosstalk with microglia cells and the co-inhibitory receptor PD-1, the main target of currently approved immunotherapies. Finally, combining CCL2 inhibition with immunomodulators targeting either PD-1/PD-L1 or P-selectin/P-Selectin Ligand-1 axes in our human 3D tumouroid models and in vivo presented more favourable outcomes than each monotherapy. Taken together, we propose that CCL2-CCR2/CCR4 is a key pathway promoting breast cancer brain metastases and a promising target for an immunotherapeutic combination approach.

The local microenvironment suppresses the synergy between irradiation and anti-PD1 therapy in breast-to-brain metastasis

The brain environment is uniquely specialized to protect its neuronal tissue from excessive inflammation by tightly regulating adaptive immunity. However, in the context of brain cancer progression, this regulation can lead to a conflict between T cell activation and suppression. Here, we show that, while CD8+ T cells can infiltrate breast cancer-brain metastases, their anti-tumor cytotoxicity is locally suppressed in the brain. Conversely, CD8+ T cells exhibited tumoricidal activity in extracranial mammary lesions originating from the same cancer cells. Consequently, combined high-dose irradiation and anti-programmed cell death protein 1 (PD1) therapy was effective in extracranial tumors but not intracranial lesions. Transcriptional analyses and functional studies identified neutrophils and Trem2-expressing macrophages as key sources for local T cell suppression within the brain, providing rational targets for future therapeutic strategies.

NK cells link immune-checkpoint blockade immunotherapy and response in melanoma brain metastases

Melanoma brain metastases (BMs) pose a significant clinical challenge. This commentary highlights the emerging understanding of the mechanisms behind immune-checkpoint blockade (ICB) efficacy in melanoma BMs. Specifically, we focus on a recent study by Fife et al, which revealed a non-canonical role for natural killer (NK) cells in shaping the tumor microenvironment following ICB therapy against melanoma BMs. Instead of direct tumor cell killing, this study demonstrates that ICB triggers NK cell chemokine release, CD8 T cell recruitment and enhanced antitumor immunity. The findings from this study highlight that the ICB mechanisms of action are complex and extend beyond the direct interference of inhibitor receptor-ligand interactions between cytotoxic CD8 T cells and tumor cells.

Myeloid Cells Induce Infiltration and Activation of B Cells and CD4+ T Follicular Helper Cells to Sensitize Brain Metastases to Combination Immunotherapy

Brain metastasis is a poor prognostic factor in patients with cancer. Despite showing efficacy in many extracranial tumors, immunotherapy with anti-PD-1 mAb or anti-CTLA4 mAb seems to be less effective against intracranial tumors. Promisingly, recent clinical studies have reported that combination therapy with anti-PD-1 and anti-CTLA4 mAbs has a potent antitumor effect on brain metastasis, highlighting the need to elucidate the detailed mechanisms controlling the intracranial tumor microenvironment (TME) to develop effective immunotherapeutic strategies. In this study, we analyzed the tumor-infiltrating lymphocytes in murine models of brain metastasis that responded to anti-CTLA4 and anti-PD-1 mAbs. Activated CD4+ T follicular helper (TFH) cells with high CTLA4 expression characteristically infiltrated the intracranial TME, which were activated by combination anti-CTLA4 and anti-PD-1 treatment. The loss of TFH cells suppressed the additive effect of CTLA4 blockade on anti-PD-1 mAb. B-cell-activating factor belonging to the TNF family (BAFF) and a proliferation-inducing ligand (APRIL) produced by abundant myeloid cells, particularly CD80hiCD206lo proinflammatory M1-like macrophages, in the intracranial TME induced B-cell and TFH-cell infiltration and activation. Furthermore, the intracranial TME of patients with non-small cell lung cancer featured TFH- and B-cell infiltration as tertiary lymphoid structures. Together, these findings provide insights into the immune cell cross-talk in the intracranial TME that facilitates an additive antitumor effect of CTLA4 blockade with anti-PD-1 treatment, supporting the potential of a combination immunotherapeutic strategy for brain metastases. Significance: B-cell and CD4+ T follicular helper cell activation via BAFF/APRIL from abundant myeloid cells in the intracranial tumor microenvironment enables a combinatorial effect of CTLA4 and PD-1 blockade in brain metastases.

First-line nivolumab plus platinum chemotherapy and bevacizumab for advanced nonsquamous non-small cell lung cancer: A 3-year follow-up of the phase 3 randomized TASUKI-52 trial

OBJECTIVES

In the randomized phase III TASUKI-52 trial, nivolumab with carboplatin, paclitaxel, and bevacizumab significantly prolonged the progression-free survival (PFS) of treatment-naive patients with advanced or recurrent nonsquamous non-small cell lung cancer (NSCLC). Here, we report the long-term outcomes of patients treated with nivolumab plus carboplatin, paclitaxel, and bevacizumab with 3 years of follow-up.

METHODS

Patients with stage IIIB/IV or recurrent nonsquamous NSCLC without sensitizing EGFR, ALK, or ROS1 mutations were randomized (1:1) to receive either nivolumab or placebo, in addition to carboplatin, paclitaxel, and bevacizumab, every 3 weeks. Treatment was continued for a maximum of six cycles. The endpoints included PFS, overall survival (OS), and safety. Exploratory analyses included efficacy and safety in subgroups.

RESULTS

A total of 550 patients were randomized to the nivolumab arm (n = 275) and placebo arm (n = 275). At the minimum follow-up of 36.1 months, PFS was consistently longer in the nivolumab arm than in the placebo arm (median, 10.6 vs. 8.2 months; hazard ratio [HR], 0.59; 95 % confidence interval [CI], 0.47-0.73; P < 0.0001), with PFS rates of 20.2 % vs. 4.9 %. The median OS was 31.6 months (95 % CI, 26.8-36.5) in the nivolumab arm and 24.7 months (95 % CI, 21.1-28.0) in the placebo arm (HR, 0.71; 95 % CI, 0.57-0.88), with OS rates of 44.2 % and 32.3 %, respectively. Of note, PFS and OS favored the nivolumab arm across patients with different PD-L1 expression levels, and regardless of baseline brain metastasis status. Grade 3-4 treatment-related adverse events occurred in 76.2 % and 74.9 % of the patients in the nivolumab and placebo arms, respectively, while no new safety concerns were identified.

CONCLUSION

Nivolumab, in addition to carboplatin, paclitaxel, and bevacizumab, remained to demonstrate significantly longer PFS and long-term OS benefit compared with placebo in the first-line treatment of patients with nonsquamous NSCLC. The extended follow-up identified no new safety signals.

Delayed central nervous system progression with atezolizumab plus chemotherapy in extensive-stage small-cell lung cancer (LU23-15)

BACKGROUND

The combination of atezolizumab with etoposide and carboplatin (AECb) has become a new standard of care for extensive-stage small-cell lung cancer (ES-SCLC). This study evaluates its impact on central nervous system (CNS) progression, specifically brain metastases.

METHOD

We analyzed the outcomes of 550 ES-SCLC patients who received first-line therapy between 2016 and 2022, focusing on time to intracranial progression (TTicP), progression-free survival (PFS), and overall survival (OS).

RESULTS

Of the 550 patients, 247 (44.9 %) received AECb, while 303 (55.1 %) received conventional chemotherapy (CTx). Intracranial progression occurred in 179 patients (32.5 %), with the AECb group showing a significantly prolonged TTicP compared to the CTx group (median 24.4 vs. 14.3 months; p = 0.038). In patients without brain metastasis at diagnosis (n = 408), TTicP was also longer in the AECb group (27.2 vs. 15.3 months; p = 0.016). This benefit persisted even after excluding patients who underwent prophylactic cranial irradiation (PCI) (27.2 vs. 15.2 months; p = 0.02) (n = 394). These findings remained consistent after adjusting for age, initial metastatic site, and PCI. Additionally, the AECb group showed improved PFS (5.0 vs. 4.7 months; p = 0.004) and OS (11.1 vs. 9.8 months; p = 0.003).

CONCLUSION

Our findings suggest that the AECb regimen is superior to conventional chemotherapy in delaying CNS progression and controlling systemic disease in ES-SCLC. These results support the AECb regimen as the new standard of care. Further research is needed to explore the mechanisms behind these improved CNS outcomes and to reassess the necessity of PCI in this treatment era.

Green chemistry: Modern therapies using nanocarriers for treating rare brain cancer metastasis from colon cancer

Brain metastasis (BM) from colon cancer is associated with a poor prognosis and restricted treatment alternatives, largely due to issues related to blood-brain barrier (BBB) permeability and the negative effects of standard chemotherapy. Nanotechnology improves treatment efficacy by enabling targeted and controlled drug delivery. This review article evaluates the potential of nanotechnology-based therapies for treating colon cancer BM, emphasizing their capacity to cross the BBB, diminish metastatic growth, and enhance overall survival rates. A review of multiple studies evaluated nanoparticles (NPs) as carriers for chemotherapy, focusing on parameters including particle size, surface charge, and drug-loading capacity. The study also reviewed studies that examined BBB penetration, in vitro tumor accumulation, and in vivo tumor growth inhibition. In vitro findings indicated that NPs accumulate more efficiently in BM tissue than in healthy brain tissue and show significant BBB penetration. In vivo, nanotherapy markedly inhibited tumor growth and prolonged survival relative to conventional chemotherapy or control treatments while also exhibiting reduced side effects. Recent studies demonstrated that plant extracts can effectively and safely synthesize nanomaterials, positioning them as a viable and environmentally friendly precursor for nanomaterial production. Nanotechnology-based therapies demonstrate significant potential in the treatment of colon cancer BM by minimizing systemic toxicity, enhancing therapeutic efficacy, and facilitating more targeted drug delivery. Further research is required to confirm these findings and implement them in clinical practice.

The research progress on meningeal metastasis in solid tumors

Meningeal metastasis (MM), particularly Leptomeningeal metastases (LM), represents the advanced stage of solid tumors and poses a significant threat to patients' lives. Moreover, it imposes a substantial burden on society. LM represents the ultimate and most fatal stage of solid tumors, inflicting devastating consequences on patients and imposing a substantial burden on society. The incidence of LM continues to rise annually, emphasizing the urgent need for early recognition and treatment initiation in individuals with LM to significantly extend overall patient survival. Despite rapid advancements in current LM detection and treatment methods, the diagnosis of LM remains constrained by several limitations such as low diagnostic efficiency, the therapeutic outcomes remain suboptimal. Furthermore, there is currently no universally recognized industry standard for LM treatment, further underscoring its status as an unresolved challenge in tumor management. Additionally, progress towards elucidating the mechanisms underlying MM has stagnated. Therefore, this review aims to comprehensively summarize recent research advances pertaining to MM in solid tumors by elucidating its underlying mechanisms, exploring diagnostic and prognostic biomarkers while addressing existing research challenges.

TIMP1 Mediates Astrocyte-Dependent Local Immunosuppression in Brain Metastasis Acting on Infiltrating CD8+ T Cells

Immunotherapies against brain metastases have shown clinical benefits when applied to asymptomatic patients, but they are largely ineffective in symptomatic cases for unknown reasons. Here, we dissect the heterogeneity in metastasis-associated astrocytes using single-cell RNA sequencing and report a population that blocks the antitumoral activity of infiltrating T cells. This protumoral activity is mediated by the secretion of tissue inhibitor of metalloproteinase-1 (TIMP1) from a cluster of pSTAT3+ astrocytes that acts on CD63+ CD8+ T cells to modulate their function. Using genetic and pharmacologic approaches in mouse and human brain metastasis models, we demonstrate that combining immune checkpoint blockade antibodies with the inhibition of astrocyte-mediated local immunosuppression may benefit patients with symptomatic brain metastases. We further reveal that the presence of tissue inhibitor of metalloproteinase-1 in liquid biopsies provides a biomarker to select patients for this combined immunotherapy. Overall, our findings demonstrate an unexpected immunomodulatory role for astrocytes in brain metastases with clinical implications. Significance: This study presents a significant advancement in understanding immune modulation in brain tumors and offers new insights into the potential therapeutic interventions for brain metastases. See related commentary by Lorger and James, p. 11.

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.

Lung Cancer with Brain Metastasis-Treatment Strategies and Molecular Characteristics

Lung cancer is a leading cause of brain metastases (BMs), with 10-20% of patients with non-small cell lung cancer (NSCLC) presenting with BMs at diagnosis and 25-50% developing them over the course of their disease. Historically, BMs have posed significant therapeutic challenges, partly due to the blood brain barrier (BBB), which restricts drug penetration to the central nervous system. Consequently, BMs were initially managed with local treatments, including surgical resection, stereotactic radiosurgery, and whole brain radiation therapy. In recent years, however, systemic treatments for BMs have advanced significantly, particularly with the development of molecularly-targeted therapies and immunotherapies. The discovery of driver mutations and the development of novel tyrosine kinase inhibitors (TKIs) have yielded encouraging intracranial responses in NSCLC patients with actionable genetic alterations (e.g., EGFR, ALK, ROS1). Genomic profiling has also suggested genetic heterogeneity between BMs and primary sites. Immunotherapies, alone or in combination with other treatments, have demonstrated promising results in NSCLC with BMs, although most clinical trials have included only selected patients with asymptomatic or previously treated BMs. In this review, we discuss the molecular and immune characteristics of NSCLC with BMs, analyze intracranial efficacy findings from clinical trials, and explore treatment strategies for lung cancer patients with BMs.

PD-L1 and VEGF dual blockade enhances anti-tumor effect on brain metastasis in hematogenous metastasis model

Immunotherapy improves survival outcomes in cancer patients, but there is still an unmet clinical need in the treatment of brain metastases. Here, we used a mouse model to investigate the antitumor effect of programmed death-ligand 1 (PD-L1) and vascular endothelial growth factor (VEGF) dual blockade on metastatic brain tumors and evaluated immune responses during treatment. After establishing hematogenous brain metastasis by transplanting murine bladder carcinoma MBT2 cells stably expressing secNLuc reporter via the internal carotid artery of C3H/HeNCrl mice, we observed the formation of metastases not only in the brain parenchyma but also in the ventricles. The observed pathological areas showed that metastases in the ventricle were histologically larger than that in the brain parenchyma. Regarding the total tumor burden in the whole brain as revealed by Nluc activities, the combination of anti-PD-L1 antibody and anti-VEGF antibody showed a stronger anti-tumor effect than each single agent. Anti-PD-L1 antibody alone enhanced CD8+ T cell priming in regional lymph nodes, increased the proportion of activated CD8+ T cells in whole brain, and increased the density of CD8+ cells in the brain parenchyma. Furthermore, anti-VEGF antibody alone decreased microvessel density (MVD) in ventricular metastases, and the combination treatment increased intratumoral CD8+ cell density in the brain parenchyma and ventricular metastases. These results suggest that PD-L1 blockade enhanced cancer immunity not only in brain metastases lesions but also in the regional lymph nodes of the metastases, and that the addition of VEGF blockade increased the antitumor effect by increasing the infiltration of activated CD8+ T cell and decreasing MVD.

Natural killer cells are required for the recruitment of CD8+ T cells and the efficacy of immune checkpoint blockade in melanoma brain metastases

Background Brain metastases (BrM) affect up to 60% of patients with metastatic melanoma and are associated with poor prognosis. While combined immune checkpoint blockade of programmed death-1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) demonstrates intracranial efficacy in a proportion of patients with melanoma, the responses are rarely durable, particularly in patients with symptomatic BrM. The brain is an immune-specialized organ and immune responses are regulated differently to the periphery.Methods Using our previously established two-site model of melanoma BrM with concomitant intracranial and extracranial tumors, in which clinically observed efficacy of the combined PD-1/CTLA-4 (PC) blockade can be reproduced, we here explored the role of natural killer (NK) cells in BrM, using functional studies, immunophenotyping and molecular profiling.Results We demonstrate that NK cells are required for the intracranial efficacy of PC blockade. While both perforin and interferon gamma were necessary for the PC blockade-dependent control of intracranial tumor growth, NK cells isolated from intracranial tumors demonstrated only a limited cancer cell killing ability, and PC blockade did not alter the abundance of NK cells within tumors. However, the depletion of NK cells in PC blockade-treated mice led to tumor molecular profiles reminiscent of those observed in intracranial tumors that failed to respond to therapy. Furthermore, the depletion of NK cells resulted in a strikingly reduced abundance of CD8+ T cells within intracranial tumors, while the abundance of other immune cell populations including CD4+ T cells, macrophages and microglia remained unaltered. Adoptive T cell transfer experiments demonstrated that PC blockade-induced trafficking of CD8+ T cells to intracranial tumors was chemokine-dependent. In line with this, PC blockade enhanced intratumoral expression of several T cell-attracting chemokines and we observed high expression levels of cognate chemokine receptors on BrM-infiltrating CD8+ T cells in mice, as well as in human BrM. Importantly, the depletion of NK cells strikingly reduced the intratumoral expression levels of T cell attracting chemokines and vascular T cell entry receptors that were upregulated following PC blockade.Conclusion Our data demonstrate that NK cells underpin the efficacy of PC blockade in BrM by orchestrating the "responder" molecular profile in tumors, and by controlling the intratumoral abundance of CD8+ T cells through regulation of multiple key molecular mediators of T cell trafficking.

T lymphocyte recruitment to melanoma brain tumors depends on distinct venous vessels

To improve immunotherapy for brain tumors, it is important to determine the principal intracranial site of T cell recruitment from the bloodstream and their intracranial route to brain tumors. Using intravital microscopy in mouse models of intracranial melanoma, we discovered that circulating T cells preferably adhered and extravasated at a distinct type of venous blood vessel in the tumor vicinity, peritumoral venous vessels (PVVs). Other vascular structures were excluded as alternative T cell routes to intracranial melanomas. Anti-PD-1/CTLA-4 immune checkpoint inhibitors increased intracranial T cell motility, facilitating migration from PVVs to the tumor and subsequently inhibiting intracranial tumor growth. The endothelial adhesion molecule ICAM-1 was particularly expressed on PVVs, and, in samples of human brain metastases, ICAM-1 positivity of PVV-like vessels correlated with intratumoral T cell infiltration. These findings uncover a distinct mechanism by which the immune system can access and control brain tumors and potentially influence other brain pathologies.

Central nervous system metastases in advanced non-small cell lung cancer: A review of the therapeutic landscape

Up to 40% of patients with non-small cell lung cancer (NSCLC) develop central nervous system (CNS) metastases. Current treatments for this subgroup of patients with advanced NSCLC include local therapies (surgery, stereotactic radiosurgery, and, less frequently, whole-brain radiotherapy), targeted therapies for oncogene-addicted NSCLC (small molecules, such as tyrosine kinase inhibitors, and antibody-drug conjugates), and immune checkpoint inhibitors (as monotherapy or combination therapy), with multiple new drugs in development. However, confirming the intracranial activity of these treatments has proven to be challenging, given that most lung cancer clinical trials exclude patients with untreated and/or progressing CNS metastases, or do not include prespecified CNS-related endpoints. Here we review progress in the treatment of patients with CNS metastases originating from NSCLC, examining local treatment options, systemic therapies, and multimodal therapeutic strategies. We also consider challenges regarding assessment of treatment response and provide thoughts around future directions for managing CNS disease in patients with advanced NSCLC.

Antibody-Drug Conjugates for the Treatment of Non-Small Cell Lung Cancer with Central Nervous System Metastases

Antibody-drug conjugates (ADCs) represent an emerging class of targeted anticancer agents that have demonstrated impressive efficacy in numerous cancer types. In non-small cell lung cancer (NSCLC), ADCs have become a component of the treatment armamentarium for a subset of patients with metastatic disease. Emerging data suggest that some ADCs exhibit impressive activity even in central nervous system (CNS) metastases, a disease site that is difficult to treat and associated with poor prognosis. Herein, we describe and summarize the existing evidence surrounding ADCs in NSCLC with a focus on CNS activity.

Machine learning-based identification of an immunotherapy-related signature to enhance outcomes and immunotherapy responses in melanoma

Background

Immunotherapy has revolutionized skin cutaneous melanoma treatment, but response variability due to tumor heterogeneity necessitates robust biomarkers for predicting immunotherapy response.

Methods

We used weighted gene co-expression network analysis (WGCNA), consensus clustering, and 10 machine learning algorithms to develop the immunotherapy-related gene model (ITRGM) signature. Multi-omics analyses included bulk and single-cell RNA sequencing of melanoma patients, mouse bulk RNA sequencing, and pathology sections of melanoma patients.

Results

We identified 66 consensus immunotherapy prognostic genes (CITPGs) using WGCNA and differentially expressed genes (DEGs) from two melanoma cohorts. The CITPG-high group showed better prognosis and enriched immune activities. DEGs between CITPG-high and CITPG-low groups in the TCGA-SKCM cohort were analyzed in three additional melanoma cohorts using univariate Cox regression, resulting in 44 consensus genes. Using 101 machine learning algorithm combinations, we constructed the ITRGM signature based on seven model genes. The ITRGM outperformed 37 published signatures in predicting immunotherapy prognosis across the training cohort, three testing cohorts, and a meta-cohort. It effectively stratified patients into high-risk or low-risk groups for immunotherapy response. The low-risk group, with high levels of model genes, correlated with increased immune characteristics such as tumor mutation burden and immune cell infiltration, indicating immune-hot tumors with a better prognosis. The ITRGM's relationship with the tumor immune microenvironment was further validated in our experiments using pathology sections with GBP5, an important model gene, and CD8 IHC analysis. The ITRGM also predicted better immunotherapy response in eight cohorts, including urothelial carcinoma and stomach adenocarcinoma, indicating broad applicability.

Conclusions

The ITRGM signature is a stable and robust predictor for stratifying melanoma patients into 'immune-hot' and 'immune-cold' tumors, enhancing prognosis and response to immunotherapy.

Toxoplasma gondii infection supports the infiltration of T cells into brain tumors

Few T cells infiltrate into primary brain tumors, fundamentally hampering the effectiveness of immunotherapy. We hypothesized that Toxoplasma gondii, a microorganism that naturally elicits a Th1 response in the brain, can promote T cell infiltration into brain tumors despite their immune suppressive microenvironment. Using a mouse genetic model for medulloblastoma, we found that T. gondii infection induced the infiltration of activatable T cells into the tumor mass and led to myeloid cell reprogramming toward a T cell-supportive state, without causing severe health issues in mice. The study provides a concrete foundation for future studies to take advantage of the immune modulatory capacity of T. gondii to facilitate brain tumor immunotherapy.

TRP-2 / gp100 DNA vaccine and PD-1 checkpoint blockade combination for the treatment of intracranial tumors

Intracranial tumors present a significant therapeutic challenge due to their physiological location. Immunotherapy presents an attractive method for targeting these intracranial tumors due to relatively low toxicity and tumor specificity. Here we show that SCIB1, a TRP-2 and gp100 directed ImmunoBody® DNA vaccine, generates a strong TRP-2 specific immune response, as demonstrated by the high number of TRP2-specific IFNγ spots produced and the detection of a significant number of pentamer positive T cells in the spleen of vaccinated mice. Furthermore, vaccine-induced T cells were able to recognize and kill B16HHDII/DR1 cells after a short in vitro culture. Having found that glioblastoma multiforme (GBM) expresses significant levels of PD-L1 and IDO1, with PD-L1 correlating with poorer survival in patients with the mesenchymal subtype of GBM, we decided to combine SCIB1 ImmunoBody® with PD-1 immune checkpoint blockade to treat mice harboring intracranial tumors expressing TRP-2 and gp100. Time-to-death was significantly prolonged, and this correlated with increased CD4+ and CD8+ T cell infiltration in the tissue microenvironment (TME). However, in addition to PD-L1 and IDO, the GBM TME was found to contain a significant number of immunoregulatory T (Treg) cell-associated transcripts, and the presence of such cells is likely to significantly affect clinical outcome unless also tackled.

The ERK inhibitor LY3214996 augments anti-PD-1 immunotherapy in preclinical mouse models of BRAFV600E melanoma brain metastasis

BACKGROUND

Immune checkpoint inhibitors (ICI) have revolutionized cancer treatment; however, only a subset of patients with brain metastasis (BM) respond to ICI. Activating mutations in the mitogen-activated protein kinase signaling pathway are frequent in BM. The objective of this study was to evaluate whether therapeutic inhibition of extracellular signal-regulated kinase (ERK) can improve the efficacy of ICI for BM.

METHODS

We used immunotypical mouse models of BM bearing dual extracranial/intracranial tumors to evaluate the efficacy of single-agent and dual-agent treatment with selective ERK inhibitor LY3214996 (LY321) and anti-programmed death receptor 1 (PD-1) antibody. We verified target inhibition and drug delivery, then investigated treatment effects on T-cell response and tumor-immune microenvironment using high-parameter flow cytometry, multiplex immunoassays, and T-cell receptor profiling.

RESULTS

We found that dual treatment with LY321 and anti-PD-1 significantly improved overall survival in 2 BRAFV600E-mutant murine melanoma models but not in KRAS-mutant murine lung adenocarcinoma. We demonstrate that although LY321 has limited blood-brain barrier (BBB) permeability, combined LY321 and anti-PD-1 therapy increases tumor-infiltrating CD8+ effector T cells, broadens the T-cell receptor repertoire in the extracranial tumor, enriches T-cell clones shared by the periphery and brain, and reduces immunosuppressive cytokines and cell populations in tumors.

CONCLUSIONS

Despite the limited BBB permeability of LY321, combined LY321 and anti-PD-1 treatment can improve intracranial disease control by amplifying extracranial immune responses, highlighting the role of extracranial tumors in driving intracranial response to treatment. Combined ERK and PD-1 inhibition is a promising therapeutic approach, worthy of further investigation for patients with melanoma BM.

Immunotherapy With Radiotherapy for Brain Metastases in Patients With NSCLC: NEJ060

Introduction

Immune checkpoint inhibitor (ICI)-based treatment has become standard treatment for patients with advanced NSCLC. We aimed to determine the survival benefit of upfront radiotherapy for brain metastases (BMs) in patients with NSCLC who received ICI alone (ICI-alone) or with chemotherapy (ICI-chemo).

Methods

This study included consecutive patients with NSCLC having BMs who received ICI alone or ICI-chemo at 50 institutes between February 2017 and September 2021. The presence of BMs was confirmed by imaging before treatment. Treatment outcomes were compared between patients who did and did not receive upfront radiotherapy for BMs. Potential confounding factors were adjusted between the groups through inverse probability treatment weighting (IPTW) analysis and overlap weighting (OW) analysis with propensity scores.

Results

Patients were grouped as ICI-alone cohort, 224 patients (upfront-radiotherapy group, 135 patients; no-radiotherapy group, 89 patients) and ICI-chemo cohort, 367 patients (upfront-radiotherapy group, 212 patients; no-radiotherapy group, 155 patients). In the ICI-alone cohort, the overall survival of the upfront-radiotherapy group was significantly longer than that of the no-radiotherapy group (IPTW-adjusted hazards ratio [HR] = 0.45 [95% confidence interval [CI]: 0.29-0.72], OW-adjusted HR = 0.52 [95% CI: 0.35-0.77]). In contrast, in the ICI-chemo cohort, the OS of the upfront-radiotherapy group was not significantly different from that of the no-radiotherapy group (IPTW-adjusted HR = 1.02 [95% CI: 0.70-1.48], OW-adjusted HR = 0.93 [95% CI: 0.65-1.33]).

Conclusions

Upfront radiotherapy for BMs was associated with longer overall survival in patients with NSCLC who received ICI alone; however, it did not exhibit survival benefits in the patients who received ICI-chemo.

Immunotherapy-associated cardiovascular toxicities: insights from preclinical and clinical studies

Immune checkpoint inhibitors (ICIs) have become a widely accepted and effective treatment for various types of solid tumors. Recent studies suggest that cardiovascular immune-related adverse events (irAEs) specifically have an incidence rate ranging from 1.14% to more than 5%. Myocarditis is the most common observed cardiovascular irAE. Others include arrhythmias, pericardial diseases, vasculitis, and a condition resembling takotsubo cardiomyopathy. Programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) pathway, cytotoxic T-lymphocyte antigen-4 (CTLA-4) pathway, and the recently discovered lymphocyte-activation gene 3 (LAG-3) pathway, play a critical role in boosting the body's natural immune response against cancer cells. While ICIs offer significant benefits in terms of augmenting immune function, they can also give rise to unwanted inflammatory side effects known as irAEs. The occurrence of irAEs can vary in severity, ranging from mild to severe, and can impact the overall clinical efficacy of these agents. This review aims to summarize the underlying mechanisms of cardiovascular irAE from both preclinical and clinical studies for a better understanding of cardiovascular irAE in clinical application.

Progress of immune checkpoint inhibitors therapy for non-small cell lung cancer with liver metastases

Nearly one-fifth of patients with non-small cell Lung Cancer (NSCLC) will develop liver metastases (LMs), and the overall treatment strategy of LMs will directly affect the survival of patients. However, some retrospective studies have found that patients receiving chemotherapy or targeted therapy have a poorer prognosis once LMs develop. In recent years, multiple randomised controlled trials (RCTS) have shown significant improvements in outcomes for patients with advanced lung cancer following the introduction of immune checkpoint inhibitors (ICIs) compared to conventional chemotherapy. ICIs is safe and effective in patients with LMs, although patients with LMs are mostly underrepresented in randomised clinical trials. However, NSCLC patients with LMs have a significantly worse prognosis than those without LMs when treated with ICIs, and the mechanism by which LMs induce systemic anti-tumour immunity reduction is unknown, so the management of LMs in patients with NSCLC is a clinical challenge that requires more optimised therapies to achieve effective disease control. In this review, we summarised the mechanism of ICIs in the treatment of LMs, the clinical research and treatment progress of ICIs and their combination with other therapies in patients with LMs from NSCLC.

The Role of Microglia in Brain Metastases: Mechanisms and Strategies

Brain metastases and related complications are one of the major fatal factors in cancer. Patients with breast cancer, lung cancer, and melanoma are at a high risk of developing brain metastases. However, the mechanisms underlying the brain metastatic cascade remain poorly understood. Microglia, one of the major resident macrophages in the brain parenchyma, are involved in multiple processes associated with brain metastasis, including inflammation, angiogenesis, and immune modulation. They also closely interact with metastatic cancer cells, astrocytes, and other immune cells. Current therapeutic approaches against metastatic brain cancers, including small-molecule drugs, antibody-coupled drugs (ADCs), and immune-checkpoint inhibitors (ICIs), have compromised efficacy owing to the impermeability of the blood-brain barrier (BBB) and complex brain microenvironment. Targeting microglia is one of the strategies for treating metastatic brain cancer. In this review, we summarize the multifaceted roles of microglia in brain metastases and highlight them as potential targets for future therapeutic interventions.

CDK4/6 Inhibition Sensitizes Intracranial Tumors to PD-1 Blockade in Preclinical Models of Brain Metastasis

PURPOSE

Brain metastases are associated with high morbidity and are often resistant to immune checkpoint inhibitors. We evaluated whether CDK4/6 inhibitor (CDKi) abemaciclib can sensitize intracranial tumors to programmed cell death protein 1 (PD-1) inhibition in mouse models of melanoma and breast cancer brain metastasis.

EXPERIMENTAL DESIGN

Treatment response was evaluated in vivo using immunocompetent mouse models of brain metastasis bearing concurrent intracranial and extracranial tumors. Treatment effect on intracranial and extracranial tumor-immune microenvironments (TIME) was evaluated using immunofluorescence, multiplex immunoassays, high-parameter flow cytometry, and T-cell receptor profiling. Mice with humanized immune systems were evaluated using flow cytometry to study the effect of CDKi on human T-cell development.

RESULTS

We found that combining abemaciclib with PD-1 inhibition reduced tumor burden and improved overall survival in mice. The TIME, which differed on the basis of anatomic location of tumors, was altered with CDKi and PD-1 inhibition in an organ-specific manner. Combination abemaciclib and anti-PD-1 treatment increased recruitment and expansion of CD8+ effector T-cell subsets, depleted CD4+ regulatory T (Treg) cells, and reduced levels of immunosuppressive cytokines in intracranial tumors. In immunodeficient mice engrafted with human immune systems, abemaciclib treatment supported development and maintenance of CD8+ T cells and depleted Treg cells.

CONCLUSIONS

Our results highlight the distinct properties of intracranial and extracranial tumors and support clinical investigation of combination CDK4/6 and PD-1 inhibition in patients with brain metastases. See related commentary by Margolin, p. 257.

Anti-CTLA-4 nanobody as a promising approach in cancer immunotherapy

Cancer is one of the most common diseases and causes of death worldwide. Since common treatment approaches do not yield acceptable results in many patients, developing innovative strategies for effective treatment is necessary. Immunotherapy is one of the promising approaches that has been highly regarded for preventing tumor recurrence and new metastases. Meanwhile, inhibiting immune checkpoints is one of the most attractive methods of cancer immunotherapy. Cytotoxic T lymphocyte-associated protein-4 (CTLA-4) is an essential immune molecule that plays a vital role in cell cycle modulation, regulation of T cell proliferation, and cytokine production. This molecule is classically expressed by stimulated T cells. Inhibition of overexpression of immune checkpoints such as CTLA-4 receptors has been confirmed as an effective strategy. In cancer immunotherapy, immune checkpoint-blocking drugs can be enhanced with nanobodies that target immune checkpoint molecules. Nanobodies are derived from the variable domain of heavy antibody chains. These small protein fragments have evolved entirely without a light chain and can be used as a powerful tool in imaging and treating diseases with their unique structure. They have a low molecular weight, which makes them smaller than conventional antibodies while still being able to bind to specific antigens. In addition to low molecular weight, specific binding to targets, resistance to temperature, pH, and enzymes, high ability to penetrate tumor tissues, and low toxicity make nanobodies an ideal approach to overcome the disadvantages of monoclonal antibody-based immunotherapy. In this article, while reviewing the cellular and molecular functions of CTLA-4, the structure and mechanisms of nanobodies' activity, and their delivery methods, we will explain the advantages and challenges of using nanobodies, emphasizing immunotherapy treatments based on anti-CTLA-4 nanobodies.

Treatment Advances in Lung Cancer with Leptomeningeal Metastasis

Leptomeningeal metastasis (LM) is a serious and often fatal complication in patients with advanced lung cancer, resulting in significant neurological deficits, decreased quality of life, and a poor prognosis. This article summarizes current research advances in treating lung cancer with meningeal metastases, discusses clinical challenges, and explores treatment strategies. Through an extensive review of relevant clinical trial reports and screening of recent conference abstracts, we collected clinical data on treating patients with lung cancer with meningeal metastases to provide an overview of the current research progress. Exciting progress has been made by focusing on specific mutations within lung cancer, including the use of EGFR tyrosine kinase inhibitors or inhibitors for anaplastic lymphoma kinase gene rearrangement, such as osimertinib, alectinib, and lorlatinib. These targeted therapies have shown impressive results in penetrating the central nervous system (CNS). Regarding whole-brain radiotherapy, there is currently some controversy among investigators regarding its effect on survival. Additionally, immune checkpoint inhibitors (ICIs) have demonstrated reliable clinical benefits due to their ability to retain anticancer activity in CNS metastases. Moreover, combination therapy shows promise in providing further treatment possibilities. Considerable progress has been made in the clinical research of lung cancer with LM. However, the sample size of prospective clinical trials investigating LM for lung cancer is still limited, with most reports being retrospective. Developing more effective management protocols for metastatic LM in lung cancer remains an ongoing challenge for the future.

Nanomaterials for brain metastasis

Tumor metastasis is a significant contributor to the mortality of cancer patients. Specifically, current conventional treatments are unable to achieve complete remission of brain metastasis. This is due to the unique pathological environment of brain metastasis, which differs significantly from peripheral metastasis. Brain metastasis is characterized by high tumor mutation rates and a complex microenvironment with immunosuppression. Additionally, the presence of blood-brain barrier (BBB)/blood tumor barrier (BTB) restricts drug leakage into the brain. Therefore, it is crucial to take account of the specific characteristics of brain metastasis when developing new therapeutic strategies. Nanomaterials offer promising opportunities for targeted therapies in treating brain metastasis. They can be tailored and customized based on specific pathological features and incorporate various treatment approaches, which makes them advantageous in advancing therapeutic strategies for brain metastasis. This review provides an overview of current clinical treatment options for patients with brain metastasis. It also explores the roles and changes that different cells within the complex microenvironment play during tumor spread. Furthermore, it highlights the use of nanomaterials in current brain treatment approaches.

Shenqi Fuzheng injection modulates tumor fatty acid metabolism to downregulate MDSCs infiltration, enhancing PD-L1 antibody inhibition of intracranial growth in Melanoma

BACKGROUND

Addressing brain metastases in cancer presents substantial challenges due to limited therapeutic options and high mortality rates. In clinical practice, the amalgamation of traditional Chinese medicine with other treatment modalities has exhibited noteworthy efficacy in managing disease progression and enhancing quality of life.

OBJECTIVE

To substantiate the regulatory effects of Shenqi Fuzheng Injection (SFI) on the microenvironment of melanoma brain metastases and appraise whether SFI augments the anti-tumour effects of immune checkpoint inhibitors, with a specific focus on investigating the mechanisms underlying SFI's actions.

METHODS

Initially, we established a B16-F10 brain transplant tumour model in C57BL/6 mice using a stereotaxic apparatus. The efficacy of the drug was evaluated through in vivo imaging technology, HE staining, and immunofluorescence. Mass Cytometry (CyTOF) and flow cytometry were employed to analyse the impact of SFI on immune cell subpopulations in the tumour microenvironment. Subsequently, transcriptome sequencing and metabolomics were utilised to examine the effects of SFI on melanoma-related genes and metabolism. Molecular docking, Western Blot, and ELISA assays were conducted to investigate the targets of SFI in intervening in melanoma fatty acid metabolism. Finally, the anti-tumour effects of SFI in combination with immune checkpoint inhibitors were scrutinised in the brain transplant tumour model.

RESULTS

The pharmacological findings demonstrated that SFI inhibits the growth of melanoma brain transplant tumours in a dose-dependent manner. CyTOF, flow cytometry, and immunofluorescence results revealed that SFI significantly diminishes the levels of Myeloid-Derived Suppressor Cells (MDSCs) and Regulatory T cells (Tregs) in the tumour microenvironment while enhancing the levels of CD8+T and CD4+ T cells. Subsequently, transcriptomic and metabolomic findings, both in vitro and in vivo, indicate that SFI significantly inhibits the arachidonic acid metabolism process in melanoma cells. Molecular docking and biological experiments showed that SFI inhibits the expression of D6D and the activity of COX-2, leading to a reduction in downstream PGE2 production. Lastly, SFI significantly enhances the anti-tumour effects of PD-L1 antibody against intracranial melanoma.

CONCLUSION

SFI improves the tumour immune microenvironment in melanoma by intervening in fatty acid metabolism, thereby reducing levels of MDSCs and Tregs while increasing levels of CD8+ T and CD4+ T cells. Ultimately, this augmentation leads to enhanced anti-tumour effects of the immune checkpoint inhibitor PD-L1 antibody.

Harnessing immunotherapy for brain metastases: insights into tumor-brain microenvironment interactions and emerging treatment modalities

Brain metastases signify a deleterious milestone in the progression of several advanced cancers, predominantly originating from lung, breast and melanoma malignancies, with a median survival timeframe nearing six months. Existing therapeutic regimens yield suboptimal outcomes; however, burgeoning insights into the tumor microenvironment, particularly the immunosuppressive milieu engendered by tumor-brain interplay, posit immunotherapy as a promising avenue for ameliorating brain metastases. In this review, we meticulously delineate the research advancements concerning the microenvironment of brain metastases, striving to elucidate the panorama of their onset and evolution. We encapsulate three emergent immunotherapeutic strategies, namely immune checkpoint inhibition, chimeric antigen receptor (CAR) T cell transplantation and glial cell-targeted immunoenhancement. We underscore the imperative of aligning immunotherapy development with in-depth understanding of the tumor microenvironment and engendering innovative delivery platforms. Moreover, the integration with established or avant-garde physical methodologies and localized applications warrants consideration in the prevailing therapeutic schema.

Immunotherapy-Associated Atherosclerosis: A Comprehensive Review of Recent Findings and Implications for Future Research

Purpose of the Review

Even as immune checkpoint inhibitors (ICIs) have transformed the lifespan of many patients, they may also trigger acceleration of long-term cardiovascular disease. Our review aims to examine the current landscape of research on ICI-mediated atherosclerosis and address key questions regarding its pathogenesis and impact on patient management.

Recent Findings

Preclinical mouse models suggest that T cell dysregulation and proatherogenic cytokine production are key contributors to plaque development after checkpoint inhibition. Clinical data also highlight the significant burden of atherosclerotic cardiovascular disease (ASCVD) in patients on immunotherapy, although the value of proactively preventing and treating ASCVD in this population remains an open area of inquiry. Current treatment options include dietary/lifestyle modification and traditional medications to manage hypertension, hyperlipidemia, and diabetes risk factors; no current targeted therapies exist.

Summary

Early identification of high-risk patients is crucial for effective preventive strategies and timely intervention. Future research should focus on refining screening tools, elucidating targetable mechanisms driving ICI atherosclerosis, and evaluating long-term cardiovascular outcomes in cancer survivors who received immunotherapy. Moreover, close collaboration between oncologists and cardiologists is essential to optimize patient outcomes.

The nexus of natural killer cells and melanoma tumor microenvironment: crosstalk, chemotherapeutic potential, and innovative NK cell-based therapeutic strategies

The metastasis of melanoma cells to regional lymph nodes and distant sites is an important contributor to cancer-related morbidity and mortality among patients with melanoma. This intricate process entails dynamic interactions involving tumor cells, cellular constituents, and non-cellular elements within the microenvironment. Moreover, both microenvironmental and systemic factors regulate the metastatic progression. Central to immunosurveillance for tumor cells are natural killer (NK) cells, prominent effectors of the innate immune system with potent antitumor and antimetastatic capabilities. Recognizing their pivotal role, contemporary immunotherapeutic strategies are actively integrating NK cells to combat metastatic tumors. Thus, a meticulous exploration of the interplay between metastatic melanoma and NK cells along the metastatic cascade is important. Given the critical involvement of NK cells within the melanoma tumor microenvironment, this comprehensive review illuminates the intricate relationship between components of the melanoma tumor microenvironment and NK cells, delineating their multifaceted roles. By shedding light on these critical aspects, this review advocates for a deeper understanding of NK cell dynamics within the melanoma context, driving forward transformative strategies to combat this cancer.

Differential requirements for CD4+ T cells in the efficacy of the anti-PD-1+LAG-3 and anti-PD-1+CTLA-4 combinations in melanoma flank and brain metastasis models

BACKGROUND

Although the anti-PD-1+LAG-3 and the anti-PD-1+CTLA-4 combinations are effective in advanced melanoma, it remains unclear whether their mechanisms of action overlap.

METHODS

We used single cell (sc) RNA-seq, flow cytometry and IHC analysis of responding SM1, D4M-UV2 and B16 melanoma flank tumors and SM1 brain metastases to explore the mechanism of action of the anti-PD-1+LAG-3 and the anti-PD-1+CTLA-4 combination. CD4+ and CD8+ T cell depletion, tetramer binding assays and ELISPOT assays were used to demonstrate the unique role of CD4+T cell help in the antitumor effects of the anti-PD-1+LAG-3 combination.

RESULTS

The anti-PD-1+CTLA-4 combination was associated with the infiltration of FOXP3+regulatory CD4+ cells (Tregs), fewer activated CD4+T cells and the accumulation of a subset of IFNγ secreting cytotoxic CD8+T cells, whereas the anti-PD-1+LAG-3 combination led to the accumulation of CD4+T helper cells that expressed CXCR4, TNFSF8, IL21R and a subset of CD8+T cells with reduced expression of cytotoxic markers. T cell depletion studies showed a requirement for CD4+T cells for the anti-PD-1+LAG-3 combination, but not the PD-1-CTLA-4 combination at both flank and brain tumor sites. In anti-PD-1+LAG-3 treated tumors, CD4+T cell depletion was associated with fewer activated (CD69+) CD8+T cells and impaired IFNγ release but, conversely, increased numbers of activated CD8+T cells and IFNγ release in anti-PD-1+CTLA-4 treated tumors.

CONCLUSIONS

Together these studies suggest that these two clinically relevant immune checkpoint inhibitor (ICI) combinations have differential effects on CD4+T cell polarization, which in turn, impacted cytotoxic CD8+T cell function. Further insights into the mechanisms of action/resistance of these clinically-relevant ICI combinations will allow therapy to be further personalized.

Efficacy and safety of the combined use of ipilimumab and nivolumab for melanoma patients with brain metastases: a systematic review and meta-analysis

CONTEXT

Immune checkpoint inhibitors have advanced immunotherapy for melanoma patients.Objective: This study evaluates efficacy and safety of ipilimumab and nivolumab combination (IN) for melanoma brain metastases (MBM) patients.

MATERIALS AND METHODS

Literature search was conducted in electronic databases and studies were included if they reported efficacy and safety of IN in MBM patients or prognostic information related to brain metastases. Outcomes evaluated were objective response rate (ORR), complete remission/stable disease/progressive disease rates, progression-free survival (PFS), overall survival (OS), incidence rates of adverse events, and hazard ratios of disease progression or mortality between IN-treated patients with and without brain metastasis.

RESULTS

Intracranial ORR was higher in IN-treated MBM patients than with control therapies (nivolumab or ipilimumab plus fotemustine). IN treatment led to longer PFS and OS in than control treatments. Five-year OS of IN-treated MBM patients was up to 51% compared to 34% for nivolumab. Outcomes were better for treatment naïve and asymptomatic patients. Whereas many studies reported significantly higher mortality or progression risk with IN treatment in MBM patients compared to non-MBM melanoma patients, many others did not find this risk significant. Incidence of grade 3/4 adverse events in IN-treated MBM patients was: diarrhea or colitis (16%), hepatitis (15%), rash (8%), increased alanine transaminase (8%), increased aspartate aminotransferase (7%), increased lipase (6%), increased amylase (4%), fatigue (3%), hypophysitis (2%), pneumonitis (2%), headache (2%), nausea or vomiting (1%), and neutropenia (1%).

CONCLUSION

IN is an efficacious and safer treatment option for MBM patients, especially for asymptomatic and treatment naïve patients.

Immunotherapy in the context of immune-specialized environment of brain metastases

Brain metastases (BrM) develop in 20-40% of patients with advanced cancer. They mainly originate from lung cancer, melanoma, breast cancer, and renal cell carcinoma, and are associated with a poor prognosis. While patients with BrM traditionally lack effective treatment options, immunotherapy is increasingly gaining in importance in this group of patients, with clinical trials in the past decade demonstrating the efficacy and safety of immune checkpoint blockade in BrM originating from specific tumor types, foremost melanoma. The brain is an immune-specialized environment with several unique molecular, cellular, and anatomical features that affect immune responses, including those against tumors. In this review we discuss the potential role that some of these unique characteristics may play in the efficacy of immunotherapy, mainly focusing on the lymphatic drainage in the brain and the role of systemic anti-tumor immunity that develops due to the presence of concurrent extracranial disease in addition to BrM.

Progress of immune checkpoint inhibitors therapy for non-small cell lung cancer with brain metastases

About 40% of patients with non-small cell lung cancer (NSCLC) develop brain metastases (BMs) throughout the disease, and the occurrence of BMs is considered to have a fairly high mortality rate. Therefore, the management of brain metastases in NSCLC patients is a clinical challenge. Currently, multidisciplinary diagnosis and treatment methods are often used to achieve effective control of intracranial disease and prolong survival. Immunotherapy (IT) is one of the core therapies for NSCLC. Single or combined IT represented by immune checkpoint inhibitors(ICIs) of programmed death-1(PD-1)/ programmed cell death-ligand 1 (PD-L1) can significantly improve the prognosis of patients with advanced NSCLC.ICIs has been shown to be safe and effective in patients with BMs, although patients with BMs are mostly underrepresented in randomized clinical trials. In this review, we summarized the mechanism of ICIs in the treatment of BMs, and the clinical research and treatment progress of ICIs and their combination with other therapies in patients with BMs s from NSCLC.

Dendritic cell vaccine of gliomas: challenges from bench to bed

Gliomas account for the majority of brain malignant tumors. As the most malignant subtype of glioma, glioblastoma (GBM) is barely effectively treated by traditional therapies (surgery combined with radiochemotherapy), resulting in poor prognosis. Meanwhile, due to its "cold tumor" phenotype, GBM fails to respond to multiple immunotherapies. As its capacity to prime T cell response, dendritic cells (DCs) are essential to anti-tumor immunity. In recent years, as a therapeutic method, dendritic cell vaccine (DCV) has been immensely developed. However, there have long been obstacles that limit the use of DCV yet to be tackled. As is shown in the following review, the role of DCs in anti-tumor immunity and the inhibitory effects of tumor microenvironment (TME) on DCs are described, the previous clinical trials of DCV in the treatment of GBM are summarized, and the challenges and possible development directions of DCV are analyzed.

A case of discordant histology and expression of programmed death ligand 1 between primary tumor and brain metastases in adenosquamous carcinoma of the lung

A patient presented with vomiting and gait disturbance. Investigation revealed a single cerebellar tumor and another tumor in the upper lobe of the left lung. Based on the severe vomiting and gait disturbance, we removed the cerebellar tumor first, achieving resolution of symptoms. The cerebellar tumor was pathologically diagnosed as metastatic lung adenocarcinoma. No other metastases were identified, including in the mediastinal lymph nodes. We therefore resected the primary lung tumor. On final pathological analysis, the tumor in the upper lobe of the left lung was diagnosed as adenosquamous carcinoma with no lymph node metastasis. PD-L1 expression was low in the primary lung adenosquamous carcinoma and high in the cerebellar metastasis. Furthermore, both tumors were KRASG12C -positive. Tumor PD-L1 expression is considered important for immune escape. In this case, adenocarcinoma cells in the primary adenosquamous carcinoma may have migrated to form a cerebellar metastasis. In advanced lung cancer, tumor growth may be observed in some lesions even when many other lesions are controlled by chemo- or immunotherapy. Biopsy to confirm histology and PD-L1 expression is worth considering, depending on the location of the metastases and the invasiveness of the biopsy procedure.

Nanomaterials with dual immunomodulatory functions for synergistic therapy of breast cancer brain metastases

A long-standing paucity of effective therapies results in the poor outcomes of triple-negative breast cancer brain metastases. Immunotherapy has made progress in the treatment of tumors, but limited by the non-immunogenicity of tumors and strong immunosuppressive environment, patients with TNBC brain metastases have not yet benefited from immunotherapy. Dual immunoregulatory strategies with enhanced immune activation and reversal of the immunosuppressive microenvironment provide new therapeutic options for patients. Here, we propose a cocktail-like therapeutic strategy of microenvironment regulation-chemotherapy-immune synergistic sensitization and construct reduction-sensitive immune microenvironment regulation nanomaterials (SIL@T). SIL@T modified with targeting peptide penetrates the BBB and is subsequently internalized into metastatic breast cancer cells, releasing silybin and oxaliplatin responsively in the cells. SIL@T preferentially accumulates at the metastatic site and can significantly prolong the survival period of model animals. Mechanistic studies have shown that SIL@T can effectively induce immunogenic cell death of metastatic cells, activate immune responses and increase infiltration of CD8⁺ T cells. Meanwhile, the activation of STAT3 in the metastatic foci is attenuated and the immunosuppressive microenvironment is reversed. This study demonstrates that SIL@T with dual immunomodulatory functions provides a promising immune synergistic therapy strategy for breast cancer brain metastases.

Leptomeningeal Metastases in Melanoma Patients: An Update on and Future Perspectives for Diagnosis and Treatment

Leptomeningeal disease (LMD) is a devastating complication of cancer with a particularly poor prognosis. Among solid tumours, malignant melanoma (MM) has one of the highest rates of metastasis to the leptomeninges, with approximately 10-15% of patients with advanced disease developing LMD. Tumour cells that metastasise to the brain have unique properties that allow them to cross the blood-brain barrier, evade the immune system, and survive in the brain microenvironment. Metastatic colonisation is achieved through dynamic communication between metastatic cells and the tumour microenvironment, resulting in a tumour-permissive milieu. Despite advances in treatment options, the incidence of LMD appears to be increasing and current treatment modalities have a limited impact on survival. This review provides an overview of the biology of LMD, diagnosis and current treatment approaches for MM patients with LMD, and an overview of ongoing clinical trials. Despite the still limited efficacy of current therapies, there is hope that emerging treatments will improve the outcomes for patients with LMD.

Leveraging translational insights toward precision medicine approaches for brain metastases

Due to increasing incidence and limited treatments, brain metastases (BM) are an emerging unmet need in modern oncology. Development of effective therapeutics has been hindered by unique challenges. Individual steps of the brain metastatic cascade are driven by distinctive biological processes, suggesting that BM possess intrinsic biological differences compared to primary tumors. Here, we discuss the unique physiology and metabolic constraints specific to BM as well as emerging treatment strategies that leverage potential vulnerabilities.

Pembrolizumab in brain metastases of diverse histologies: phase 2 trial results

Brain metastases (BMs) are an emerging challenge in oncology due to increasing incidence and limited treatments. Here, we present results of a single-arm, open-label, phase 2 trial evaluating intracranial efficacy of pembrolizumab, a programmed cell death protein 1 inhibitor, in 9 patients with untreated BMs (cohort A) and 48 patients with recurrent and progressive BMs (cohort B) across different histologies. The primary endpoint was the proportion of patients achieving intracranial benefit, defined by complete response, partial response or stable disease. The primary endpoint was met with an intracranial benefit rate of 42.1% (90% confidence interval (CI): 31-54%). The median overall survival, a secondary endpoint, was 8.0 months (90% CI: 5.5-8.7 months) across both cohorts, 6.5 months (90% CI: 4.5-18.7 months) for cohort A and 8.1 months (90% CI: 5.3-9.6 months) for cohort B. Seven patients (12.3%), encompassing breast, melanoma and sarcoma histologies, had overall survival greater than 2 years. Thirty patients (52%; 90% CI: 41-64%) had one or more grade-3 or higher adverse events that were at least possibly treatment related. Two patients had grade-4 adverse events (cerebral edema) that were deemed at least possibly treatment related. These results suggest that programmed cell death protein 1 blockade may benefit a select group of patients with BMs, and support further studies to identify biomarkers and mechanisms of resistance. ClinicalTrials.gov identifier: NCT02886585.

Disruptions of Circadian Genes in Cutaneous Melanoma-An In Silico Analysis of Transcriptome Databases

Circadian genes are a set of genes that regulate the body's internal clock and influence various physiological processes, including sleep-wake cycles, metabolism and immune function. Skin cutaneous melanoma (SKCM) is a type of skin cancer that arises from the pigment-producing cells in the skin and is the most deadly form of skin cancer. This study has investigated the relevance of circadian gene expression and immune infiltrations in the outcomes of cutaneous melanoma patients. In the present study, in silico methods based on the GEPIa, TIMER 2.0 and cBioPortal databases were performed, so as to investigate the transcript level and prognostic value of 24 circadian genes in SKCM and their relationship with the immune infiltration level. The in silico analysis showed that significantly more than half of the investigated circadian genes have an altered transcript pattern in cutaneous melanoma compared to normal skin. The mRNA levels of TIMELES and BHLHE41 were upregulated, whereas those of NFIL3, BMAL1, HLF, TEF, RORA, RORC, NR1D1, PER1, PER2, PER3, CRY2 and BHLHE40 were downregulated. The presented research shows that SKCM patients with at least one alteration of their circadian genes have decreased overall survival. Additionally, majority of the circadian genes are significantly corelated with the immune cells' infiltration level. The strongest correlation was found for neutrophils and was followed by circadian genes: NR1D2 r = 0.52 p < 0.0001, BMAL1 r = 0.509 p < 0.0001; CLOCK r = 0.45 p < 0.0001; CSNKA1A1 r = 0.45 p < 0.0001; RORA r = 0.44 p < 0.0001. The infiltration level of immune cells in skin tumors has been associated with patient prognosis and treatment response. Circadian regulation of immune cell infiltration may further contribute to these prognostic and predictive markers. Examining the correlation between circadian rhythm and immune cell infiltration can provide valuable insights into disease progression and guide personalized treatment decisions.

Type I interferon response in astrocytes promotes brain metastasis by enhancing monocytic myeloid cell recruitment

Cancer metastasis to the brain is a significant clinical problem. Metastasis is the consequence of favorable interactions between invaded cancer cells and the microenvironment. Here, we demonstrate that cancer-activated astrocytes create a sustained low-level activated type I interferon (IFN) microenvironment in brain metastatic lesions. We further confirm that the IFN response in astrocytes facilitates brain metastasis. Mechanistically, IFN signaling in astrocytes activates C-C Motif Chemokine Ligand 2 (CCL2) production, which further increases the recruitment of monocytic myeloid cells. The correlation between CCL2 and monocytic myeloid cells is confirmed in clinical brain metastasis samples. Lastly, genetically or pharmacologically inhibiting C-C Motif Chemokine Receptor 2 (CCR2) reduces brain metastases. Our study clarifies a pro-metastatic effect of type I IFN in the brain even though IFN response has been considered to have anti-tumor effects. Moreover, this work expands our understandings on the interactions between cancer-activated astrocytes and immune cells in brain metastasis.

Immune checkpoint inhibitors for the treatment of non-small cell lung cancer brain metastases

ABSTRACT

Lung cancer has the highest risk of brain metastasis (BM) among all solid carcinomas. The emergence of BM has a significant impact on the selection of oncologic treatment for patients. Immune checkpoint inhibitors (ICIs) are the most promising treatment option for patients without druggable mutations and have been shown to improve survival in patients with non-small cell lung cancer (NSCLC) BM in clinical trials with good safety. Moreover, ICI has shown certain effects in NSCLC BM, and the overall intracranial efficacy is comparable to extracranial efficacy. However, a proportion of patients showed discordant responses in primary and metastatic lesions, suggesting that multiple mechanisms may exist underlying ICI activity in BM. According to studies pertaining to tumor immune microenvironments, ICIs may be capable of provoking immunity in situ. Meanwhile, systematic immune cells activated by ICIs can migrate into the central nervous system and exert antitumor effects. This review summarizes the present evidence for ICI treatment efficacy in NSCLC BM and proposes the possible mechanisms of ICI treatment for NSCLC BMs based on existing evidence.

Immune surveillance of brain metastatic cancer cells is mediated by IFITM1

Brain metastasis, most commonly originating from lung cancer, increases cancer morbidity and mortality. Although metastatic colonization is the rate-limiting and most complex step of the metastatic cascade, the underlying mechanisms are poorly understood. Here, in vivo genome-wide CRISPR-Cas9 screening revealed that loss of interferon-induced transmembrane protein 1 (IFITM1) promotes brain colonization of human lung cancer cells. Incipient brain metastatic cancer cells with high expression of IFITM1 secrete microglia-activating complement component 3 and enhance the cytolytic activity of CD8+ T cells by increasing the expression and membrane localization of major histocompatibility complex class I. After activation, microglia (of the innate immune system) and cytotoxic CD8+ T lymphocytes (of the adaptive immune system) were found to jointly eliminate cancer cells by releasing interferon-gamma and inducing phagocytosis and T-cell-mediated killing. In human cancer clinical trials, immune checkpoint blockade therapy response was significantly correlated with IFITM1 expression, and IFITM1 enhanced the brain metastasis suppression efficacy of PD-1 blockade in mice. Our results exemplify a novel mechanism through which metastatic cancer cells overcome the innate and adaptive immune responses to colonize the brain, and suggest that a combination therapy increasing IFITM1 expression in metastatic cells with PD-1 blockade may be a promising strategy to reduce metastasis.

The progress of microenvironment-targeted therapies in brain metastases

The incidence of brain metastases (BrM) has become a growing concern recently. It is a common and often fatal manifestation in the brain during the end-stage of many extracranial primary tumors. Increasing BrM diagnoses can be attributed to improvements in primary tumor treatments, which have extended patients’ lifetime, and allowed for earlier and more efficient detection of brain lesions. Currently, therapies for BrM encompass systemic chemotherapy, targeted therapy, and immunotherapy. Systemic chemotherapy regimens are controversial due to their associated side effects and limited efficacy. Targeted and immunotherapies have garnered significant attention in the medical field: they target specific molecular sites and modulate specific cellular components. However, multiple difficulties such as drug resistance and low permeability of the blood-brain barrier (BBB) remain significant challenges. Thus, there is an urgent need for novel therapies. Brain microenvironments consist of cellular components including immune cells, neurons, endothelial cells as well as molecular components like metal ions, nutrient molecules. Recent research indicates that malignant tumor cells can manipulate the brain microenvironment to change the anti-tumoral to a pro-tumoral microenvironment, both before, during, and after BrM. This review compares the characteristics of the brain microenvironment in BrM with those in other sites or primary tumors. Furthermore, it evaluates the preclinical and clinical studies of microenvironment-targeted therapies for BrM. These therapies, due to their diversity, are expected to overcome drug resistance or low permeability of the BBB with low side effects and high specificity. This will ultimately lead to improved outcomes for patients with secondary brain tumors.

Treatments for brain metastases from EGFR/ALK-negative/unselected NSCLC: A network meta-analysis

More clinical evidence is needed regarding the relative priority of treatments for brain metastases (BMs) from EGFR/ALK-negative/unselected non-small cell lung cancer (NSCLC). PubMed, EMBASE, Web of Science, Cochrane Library, and ClinicalTrials.gov databases were searched. Overall survival (OS), central nervous system progression-free survival (CNS-PFS), and objective response rate (ORR) were selected for Bayesian network meta-analyses. We included 25 eligible randomized control trials (RCTs) involving 3,054 patients, investigating nine kinds of treatments for newly diagnosed BMs and seven kinds of treatments for previously treated BMs. For newly diagnosed BMs, adding chemotherapy, EGFR-TKIs, and other innovative systemic agents (temozolomide, nitroglycerin, endostar, enzastaurin, and veliparib) to radiotherapy did not significantly prolong OS than radiotherapy alone; whereas radiotherapy + nitroglycerin showed significantly better CNS-PFS and ORR. Surgery could significantly prolong OS (hazard ratios [HR]: 0.52, 95% credible intervals: 0.41-0.67) and CNS-PFS (HR: 0.32, 95% confidence interval: 0.18-0.59) compared with radiotherapy alone. For previously treated BMs, pembrolizumab + chemotherapy, nivolumab + ipilimumab, and cemiplimab significantly prolonged OS than chemotherapy alone. Pembrolizumab + chemotherapy also showed better CNS-PFS and ORR than chemotherapy. In summary, immune checkpoint inhibitor (ICI)-based therapies, especially ICI-combined therapies, showed promising efficacies for previously treated BMs from EGFR/ALK-negative/unselected NSCLC. The value of surgery should also be emphasized. The result should be further confirmed by RCTs.