Lung Cancer Brain Metastases Research Articles

BIOM-06. NOGGIN CONTRIBUTES TO BRAIN METASTATIC COLONIZATION OF LUNG CANCER CELLS

Abstract Brain metastasis is a common complication among patients with lung cancer, yet the underlying mechanisms remain unclear. In this study, we aimed to investigate the pathogenesis of brain metastasis in lung cancer. We established highly colonizing metastatic lung cancer cells, A549-M2, through multiple implantations of A549 human lung cancer cells in the carotid artery of athymic nude mice. Compared to parental cells (M0), M2 cells demonstrated slower growth in culture plates and soft agar, as well as lower motility and higher adhesion, key characteristics of mesenchymal-epithelial transition (MET). Further analysis revealed that M2 cells exhibited decreased expression of epithelial-mesenchymal transition markers, including ZEB1 and Vimentin. M2 cells also demonstrated reduced invasiveness in co-culture systems. RNA sequencing and gene set enrichment analysis confirmed that M2 cells underwent MET. Intriguingly, depletion of Noggin, a BMP antagonist, was observed in M2 cells, and replenishment of Noggin restored suppressed migration and invasion of M2 cells. In addition, Noggin knockdown in control M0 cells promoted cell attachment and suppressed cell migration, suggesting that Noggin reduction during brain colonization causes inhibition of migration and invasion of metastatic lung cancer cells. Our results suggest that lung cancer cells undergo MET and lose their motility and invasiveness during brain metastatic colonization, which is dependent on Noggin.

IMMU-09. REVERSING SYSTEMIC T CELL DYSFUNCTION TO LICENSE IMMUNOTHERAPY IN INTRACRANIAL TUMORS

Abstract Intracranial tumors present unique challenges for immunotherapy. These can include both local and systemic modes of immune suppression, the mechanistic underpinnings of which are incompletely understood. Our work reveals that intracranial tumors elicit systemic increases in circulating catecholamine levels, and that this chronic sympathetic hyperactivity results in T cell dysfunction that impedes immunotherapeutic efficacy. We show that treatment with b-adrenergic blockade can partially overcome the negative impacts of chronic sympathetic hyperactivity by increasing NF-kB activity in immune cells, restoring T cell polyfunctionality, favorably modifying the tumor microenvironment, and extending survival in murine models of glioblastoma treated with immune-based therapies. Furthermore, we demonstrate that extended survival is also observed in glioblastoma patients receiving b-adrenergic blockade, as well as in patients with melanoma and lung cancer brain metastases who received b-blockade alongside concomitant immune checkpoint inhibition. Importantly, while local sympathetic hyperactivity in the tumor microenvironment and b-blockade also impact the anti-tumor immune response in the context of extracranial disease, these effects are markedly more pronounced in intracranial disease. Taken together, these data reveal that sympathetic hyperactivity facilitates systemic immune dysfunction in the setting of intracranial tumors and highlight a novel role for the application of b-adrenergic blockade to license immunotherapy in intracranial malignancies.

Advances in the Management of Lung Cancer Brain Metastases

Lung cancer, both non-small cell and small cell, harbors a high propensity for spreading to the central nervous system. Radiation therapy remains the backbone of the management of brain metastases. Recent advances in stereotactic radiosurgery have expanded its indications and ongoing studies seek to elucidate optimal fractionation and coordination with systemic therapies, especially targeted inhibitors with intracranial efficacy. Efforts in whole-brain radiotherapy aim to preserve neurocognition and to investigate the need for prophylactic cranial irradiation. As novel combinatorial strategies are tested and prognostic/predictive biomarkers are identified and tested, the management of brain metastases in lung cancer will become increasingly personalized to optimally balance intracranial efficacy with preserving neurocognitive function and patient values.

TKI resistance in brain metastasis: A CTLA4 state of mind

Resistance to tyrosine kinase inhibitors (TKIs) in lung cancer brain metastasis (LCBM) remains a clinical challenge. Recently in Cancer Cell, Fu etal. reveal how TKIs reshape the immune microenvironment of LCBM and propose CTLA4 blockade as a promising strategy to overcome resistance.

Tumor cell extracellular vesicles derived long non-coding RNA X-inactive specific transcript regulates the blood–brain barrier and non-small cell lung cancer brain metastasis via miR-19b-3p/EPN2

ObjectiveTo investigate the function of tumor cell extracellular vesicles (EVs) derived long non-coding RNA X-inactive specific transcript (XIST) in non-small cell lung cancer (NSCLC) brain metastasis and to clarify its specific mechanism. MethodsEVs were isolated from A549 cells, and transmission electron microscopy, nanoparticle tracking, and western blotting were used to detect morphology and particle size of EVs. Human brain microvascular endothelial cells (HBMEC) and astrocytes were used to construct an in vitro blood–brain barrier (BBB) model. The BBB model was treated with EVs for 24 h. PKH67 staining was performed to examine EV engulfment by HBMEC and astrocytes. RT-qPCR was used to examine XIST, miR-19b-3p, and epsin 2 (EPN2) mRNA expression. Expression of EPN2 and tight junction (TJ) proteins such as claudin-5, occludin, and ZO-1 were measured using western blotting. Transepithelial electrical resistance (TEER), rhodamine-dextran, and immunofluorescence staining were performed to explore the effects of EVs and XIST on the BBB. Transwell assay was used to evaluate the invasive ability of A549 and H1299 cells. Dual-luciferase and immunoprecipitation assays were used to verify binding between miR-19b-3p, XIST, and EPN2. The Interactive Video Information System was used to observe brain metastasis of xenografts in BALB/c nude mice. ResultsA549 cell-derived EVs exhibited typical characteristics of EVs. HBMEC ingested EVs in the BBB model. EVs treatment decreased TEER and TJ protein level and increased the permeability to rhodamine-dextran. XIST was overexpressed in A549 and H1299 cells. Knockdown of XIST in A549 cell-derived EVs alleviated BBB damage and reduced NSCLC cell invasion. In vivo, XIST inhibition repressed NSCLC brain metastasis by ameliorating the BBB. Mechanistically, XIST sponged miR-19b-3p and positively regulated EPN2 expression. miR-19b-3p inhibition weakened the protective effect of XIST inhibition on the BBB. ConclusionA549 cells EVs-derived XIST inhibition ameliorates BBB injury and inhibits NSCLC brain metastasis by regulating the miR-19b-3p/EPN2 axis.

Proton pump inhibitor attenutes acidic microenvironment to improve the therapeutic effects of MSLN-CAR-T cells on the brain metastasis of solid tumors

The incidence of brain metastasis (BM) is gradually increasing, and the prognosis and therapeutic effect are poor. The emergence of immunotherapy has brought hope for the development of BM treatments. This study revealed that compared with primary cancers (PCs), BMs have a “colder” and more acidic tumor microenvironment (TME), resulting in reduced protein levels of mesothelin (MSLN), a promising target for chimeric antigen receptor-T (CAR-T) cell therapy for triple-negative breast cancer (TNBC) with BMs. These factors could significantly decrease the efficiency of MSLN-CAR-T cells in TNBC BMs. Pantoprazole (PPZ) administration at the most commonly used dose in the clinic notably increased the pondus hydrogenii (pH) of the TME, inhibited lysosomal activity, increased the membrane levels of the MSLN protein and improved the killing ability of MSLN-CAR-T cells both in vitro and in vivo. Similar results were obtained in non-small cell lung cancer (NSCLC) BMs. Hence, when administered in combination with CAR-T cells, PPZ, which increases the protein levels of target antigens, may constitute a new immunotherapeutic strategy for treating solid tumors with BMs.

Simple Analysis Using Immunohistochemical Staining for Tumor-Infiltrating Lymphocytes in Brain Metastasis of Small Cell Lung Cancer

Background: We investigated the distribution of tumor-infiltrating lymphocytes (TILs) and the expression of programmed cell death-ligand 1 (PD-L1) in patients with brain metastasis (BM) from small cell lung cancer (SCLC). Methods: A retrospective analysis was performed on 12 surgical specimens of BMs from SCLC at our institute for 5 years. The Immunofluorescence-based Tissue Microenvironment Analysis Panel (MAP) was utilized for the detection of TILs, including CD3, CD8, PD-1, and PD-L1, in pathological archival specimens of BMs. The correlation between the overall survival (OS) and the above-mentioned markers was analyzed in the patients.Results: Positive rates of CD3+ TILs in the tumor parenchyma versus tumor stroma were 0.60±0.94% versus 1.76±2.72% (p=0.010), respectively; positive rates of CD8+ TILs in the tumor parenchyma versus tumor stroma were 0.80±0.78% versus 2.46±3.72% (p=0.016), respectively. There was no co-expression of CD8+ and PD-1+ TILs in the tumor parenchyma of 11 cases, and the infiltration density of co-expressed CD3+ and PD-1+ TILs was more than 10/mm2 in only 1 case. There was no co-expression of CD3+ and PD-1+ TIL in the stroma of 10 cases, and the infiltration density of CD8+ and PD-1+ TILs was more than 10/mm2 in 2 cases. Immunohistochemistry was used to detect the expression of PD-L1 in 12 cases of BMs, and 3 cases (25%) were positive. Survival analysis showed that patients with positive CD3+ TILs had significantly longer OS (p=0.040). Conclusions: The distribution of TILs in BM of SCLC is low and mainly distributed in the stroma, with the low expression of PD-L1 in the tumor tissues.

Spatial Multiomics Reveals Intratumoral Immune Heterogeneity with Distinct Cytokine Networks in Lung Cancer Brain Metastases.

Immune cell signatures are conserved across lung cancer brain metastases, and immune-metastatic tumor cell networks have a prognostic effect, implying that targeting cytokine networks between immune and metastatic tumor cells may generate more precise immunotherapeutic approaches.

PD-1 blockade does not improve efficacy of EpCAM-directed CAR T-cell in lung cancer brain metastasis

BackgroundLung cancer brain metastasis has a devastating prognosis, necessitating innovative treatment strategies. While chimeric antigen receptor (CAR) T-cell show promise in hematologic malignancies, their efficacy in solid tumors, including brain metastasis, is limited by the immunosuppressive tumor environment. The PD-L1/PD-1 pathway inhibits CAR T-cell activity in the tumor microenvironment, presenting a potential target to enhance therapeutic efficacy. This study aims to evaluate the impact of anti-PD-1 antibodies on CAR T-cell in treating lung cancer brain metastasis.MethodsWe utilized a murine immunocompetent, syngeneic orthotopic cerebral metastasis model for repetitive intracerebral two-photon laser scanning microscopy, enabling in vivo characterization of red fluorescent tumor cells and CAR T-cell at a single-cell level over time. Red fluorescent EpCAM-transduced Lewis lung carcinoma cells (EpCAM/tdtLL/2 cells) were implanted intracranially. Following the formation of brain metastasis, EpCAM-directed CAR T-cell were injected into adjacent brain tissue, and animals received either anti-PD-1 or an isotype control.ResultsCompared to controls receiving T-cell lacking a CAR, mice receiving EpCAM-directed CAR T-cell showed higher intratumoral CAR T-cell densities in the beginning after intraparenchymal injection. This finding was accompanied with reduced tumor growth and translated into a survival benefit. Additional anti-PD-1 treatment, however, did not affect intratumoral CAR T-cell persistence nor tumor growth and thereby did not provide an additional therapeutic effect.ConclusionCAR T-cell therapy for brain malignancies appears promising. However, additional anti-PD-1 treatment did not enhance intratumoral CAR T-cell persistence or effector function, highlighting the need for novel strategies to improve CAR T-cell therapy in solid tumors.

Overcoming tyrosine kinase inhibitor resistance in lung cancer brain metastasis with CTLA4 blockade

Lung cancer brain metastasis (LCBM) poses a significant clinical challenge due to acquired resistance to tyrosine kinase inhibitor (TKI) treatment. To elucidate its underlying mechanisms, we employed single-cell RNA sequencing analysis on surgically obtained LCBM samples with diverse genetic backgrounds and TKI treatment histories. Our study uncovers that TKI treatment elevates the immune checkpoint CTLA4 expression in Tcells, promoting an immune-suppressive microenvironment. This immunomodulation is initiated by tumor-derived HMGB1 in response to TKIs. In LCBM syngeneic murine models with TKI-sensitive or TKI-resistant EGFR mutations, combining CTLA4 blockade with TKIs demonstrates enhanced efficacy over TKI monotherapy or TKIs with PD1 blockade. These findings provide insights into the TKI resistance mechanisms and highlight the potential of CTLA4 blockade in effectively overcoming TKI resistance in LCBM.

Factors associated with the distribution of brain metastases in lung cancer: a retrospective study.

The distribution of brain metastases (BMs) in patients with lung cancer may be associated with the primary tumor-related factors and cerebral small vascular diseases (CSVDs). The aim of this study was to investigate the potential effects of the above factors on the distribution of BMs. A total of 5,788 lesions in 823 patients with BMs from lung cancer were enrolled. The numbers of BMs and CSVDs in 15 brain regions were determined. CSVDs include recent small subcortical infarcts (RSSIs), perivascular spaces, and lacunes of presumed vascular origin (LPVOs). We collected the number of CSVDs, and primary tumor-related factors (including clinical and imaging features) in lung cancer patients with BMs. Univariate and multivariate linear regression were utilized to analyze the potential influence of the above factors on the number of BMs in 15 brain regions. In addition, we performed subgroup analyses of all patients with adenocarcinoma (AD), female patients with AD, male patients with AD, and patients with small cell lung cancer. Univariate linear regression analyses showed that bone metastasis, adrenal metastasis, RSSIs, and LPVOs were associated with the number of BMs in over half of the examined brain regions. Only the independent association of LVPOs persisted in the multivariate linear regression analyses, and similar phenomenon was found in the subgroup analyses. In conclusion, the distribution of BMs in lung cancer patients appears to be associated with the presence of LVPOs, while primary tumor-related factors have less influence.

Length-scale study in deep learning prediction for non-small cell lung cancer brain metastasis

Deep learning-assisted digital pathology has demonstrated the potential to profoundly impact clinical practice, even surpassing human pathologists in performance. However, as deep neural network (DNN) architectures grow in size and complexity, their explainability decreases, posing challenges in interpreting pathology features for broader clinical insights into physiological diseases. To better assess the interpretability of digital microscopic images and guide future microscopic system design, we developed a novel method to study the predictive feature length-scale that underpins a DNN’s predictive power. We applied this method to analyze a DNN’s capability in predicting brain metastasis from early-stage non-small-cell lung cancer biopsy slides. This study quantifies DNN’s attention for brain metastasis prediction, targeting features at both the cellular scale and tissue scale in H&E-stained histological whole slide images. At the cellular scale, the predictive power of DNNs progressively increases with higher resolution and significantly decreases when the resolvable feature length exceeds 5 microns. Additionally, DNN uses more macro-scale features associated with tissue architecture and is optimized when assessing visual fields greater than 41 microns. Our study computes the length-scale requirements for optimal DNN learning on digital whole-slide microscopic images, holding the promise to guide future optical microscope designs in pathology applications and facilitating downstream deep learning analysis.

Blood-brain barrier and blood-brain tumor barrier penetrating peptide-drug conjugate as targeted therapy for the treatment of lung cancer brain metastasis

Lung cancer is the leading cause of cancer deaths worldwide. Brain metastasis of lung cancer, which counts for nearly 50% of late-stage lung cancer patients, is a sign of a really poor prognosis. However, the presence of blood–brain barrier (BBB) and blood–brain tumor barrier (BBTB) limits the penetration of drugs from the blood into the brain and thus restricts their accumulation in brain tumors. Systematic delivery of drugs into brain and brain tumor lesion using BBB and BBTB penetrating vehicles represents a promising strategy to overcome the BBB and BBTB limitations. Hence, we validated one of our previously identified BBB/BBTB penetrating peptide and its drug conjugate form for the treatment of lung cancer brain metastasis. With in vitro experiment, we first validated that the receptor LRP1, which mediated the peptide penetration of the BBB, was expressed on lung cancer cells and thus can be targeted by the peptide to overcome BBTB. With this delivery peptide, we constructed peptide-paclitaxel conjugate (the PDC) and in vitro validation showed that the PDC can across the BBB and efficiently kill lung cancer cells. We therefore constructed mouse lung cancer brain metastasis xenograft. In vivo anti-tumor validations showed that the PDC efficiently inhibited the proliferation of the brain resident lung cancer cells and significantly expanded the survival of the mouse xenograft, with no visible damages to the organs. Overall, our study provided potential therapeutic drugs for the treatment of lung cancer brain metastasis that may be clinically effective in the near future.

Multimodal radiomics-based methods using deep learning for prediction of brain metastasis in non-small cell lung cancer with 18F-FDG PET/CT images

Objective. Approximately 57% of non-small cell lung cancer (NSCLC) patients face a 20% risk of brain metastases (BMs). The delivery of drugs to the central nervous system is challenging because of the blood–brain barrier, leading to a relatively poor prognosis for patients with BMs. Therefore, early detection and treatment of BMs are highly important for improving patient prognosis. This study aimed to investigate the feasibility of a multimodal radiomics-based method using 3D neural networks trained on 18F-FDG PET/CT images to predict BMs in NSCLC patients. Approach. We included 226 NSCLC patients who underwent 18F-FDG PET/CT scans of areas, including the lung and brain, prior to EGFR-TKI therapy. Moreover, clinical data (age, sex, stage, etc) were collected and analyzed. Shallow lung features and deep lung-brain features were extracted using PyRadiomics and 3D neural networks, respectively. A support vector machine (SVM) was used to predict BMs. The receiver operating characteristic (ROC) curve and F1 score were used to assess BM prediction performance. Main result. The combination of shallow lung and shallow-deep lung-brain features demonstrated superior predictive performance (AUC = 0.96 ± 0.01). Shallow-deep lung-brain features exhibited strong significance (P < 0.001) and potential predictive performance (coefficient > 0.8). Moreover, BM prediction by age was significant (P < 0.05). Significance. Our approach enables the quantitative assessment of medical images and a deeper understanding of both superficial and deep tumor characteristics. This noninvasive method has the potential to identify BM-related features with statistical significance, thereby aiding in the development of targeted treatment plans for NSCLC patients.

Application of random survival forest to establish a nomogram combining clinlabomics-score and clinical data for predicting brain metastasis in primary lung cancer.

To establish a nomogram for predicting brain metastasis (BM) in primary lung cancer at 12, 18, and 24months after initial diagnosis. In this study, we included 428 patients who were diagnosed with primary lung cancer at Harbin Medical University Cancer Hospital between January 2020 and January 2022. The endpoint event was BM. The patients were randomly categorized into two groups in a 7:3 ratio: training (n = 299) and validation (n = 129) sets. Least absolute shrinkage and selection operator was utilized to analyze the laboratory test results in the training set. Furthermore, clinlabomics-score was determined using regression coefficients. Then, clinlabomics-score was combined with clinical data to construct a nomogram using random survival forest (RSF) and Cox multivariate regression. Then, various methods were used to evaluate the performance of the nomogram. Five independent predictive factors (pathological type, diameter, lymph node metastasis, non-lymph node metastasis and clinlabomics-score) were used to construct the nomogram. In the validation set, the bootstrap C-index was 0.7672 (95% CI 0.7092-0.8037), 12-month AUC was 0.787 (95% CI 0.708-0.865), 18-month AUC was 0.809 (95% CI 0.735-0.884), and 24-month AUC was 0.858 (95% CI 0.792-0.924). In addition, the calibration curve, decision curve analysis and Kaplan-Meier curves revealed a good performance of the nomogram. Finally, we constructed and validated a nomogram to predict BM risk in primary lung cancer. Our nomogram can identify patients at high risk of BM and provide a reference for clinical decision-making at different disease time points.

Impact of lung adenocarcinoma subtypes on survival and timing of brain metastases.

Lung cancer is a devastating disease, with brain metastasis being one of the most common distant metastases of lung adenocarcinoma. This study aimed to investigate the prognostic characteristics of individuals with brain metastases originating from invasive lung adenocarcinoma of distinct pathological subtypes, providing a reference for the management of these patients. Clinical data from 156 patients with lung adenocarcinoma-derived brain metastases were collected, including age, sex, smoking status, Karnofsky Performance Status scores, pathological subtype, lymph node metastasis, tumor site, treatment mode, T stage, and N stage. Patients were classified into two groups (highly differentiated and poorly differentiated) based on their pathological subtypes. Propensity score matching was used to control for confounding factors. The prognostic value of pathological subtypes was assessed using Kaplan-Meier analysis and Cox proportional hazards regression modeling. Kaplan-Meier analysis indicated that patients in the moderately to highly differentiated group had better prognoses. Multivariate analysis revealed that being in the poorly differentiated group was a risk factor for poorer prognosis. Thoracic tumor radiation therapy, chemotherapy, and surgery positively influenced the time interval between lung cancer diagnosis and brain metastasis. The pathological subtypes of lung adenocarcinoma-derived brain metastases are associated with patient prognosis. Patients in the poorly differentiated group have worse prognoses compared to those in the moderately to highly differentiated group. Therefore, patients in the poorly differentiated group may require more frequent follow-ups and aggressive treatment.

Effect of heterozygosity loss of HLA-I on immune evasion and promotion of non-small cell lung cancer brain metastasis and immunotherapy resistance.

209 Background: HLA-I play a crucial role in T cell recognition and killing of tumor cells as well as in PD-1/PD-L1 immunotherapy. Loss of heterozygosity (LOH) of HLA-I alleles has been found to be common in lung cancer patients and influences immune escape during tumor evolution. This study aims to explore the incidence of HLA-I LOH in intracranial metastases of advanced non-small cell lung cancer patients with brain metastasis and its impact on the efficacy of immunotherapy. Methods: A total of 29 patients with non-small cell lung cancer brain metastasis were included in this study. All enrolled patients underwent either percutaneous biopsy or surgical resection of intracranial metastases and had tissue specimens from the primary lung lesions. Whole-exome sequencing was performed on all primary/metastatic lesions to determine HLA-I typing/LOH and calculate tumor mutation burden (TMB). Additionally, we assessed the expression levels of CD8 T cells in the tumor immune microenvironment. Among the enrolled patients, 20 received PD-1/PD-L1 treatment. Results: Among the enrolled patients, 82.8% (24/29) had heterozygous HLA-I typing, with HLA-I LOH present in 25% (6/24) of patients' primary lesions and 58.3% (14/24) in brain metastatic lesions. Analysis of TMB in different lesions revealed a median TMB of 7.8 mut/Mb in lesions with intact HLA-I and 11.4 mut/Mb in lesions with HLA-I LOH. Notably, the median TMB in brain metastatic lesions with HLA-I LOH was 13.2 mut/Mb, higher than that in HLA-I LOH primary lung lesions (10.1 mut/Mb). Immunohistochemistry demonstrated that CD8 T cell expression levels were lowest in brain metastatic lesions with HLA-I LOH and highest in intact HLA-I primary lung lesions. Among patients who received immunotherapy, four cases exhibited inconsistent lesion responses, with stable or regressing primary lesions but progressive intracranial metastases. Survival analysis revealed that patients with HLA-I LOH in brain metastases had significantly lower PFS compared to those without (4.1 months vs. 6.9 months, P &lt; 0.05), with no significant difference in OS. Conclusions: This study indicates that the incidence of HLA-I LOH in brain metastases of lung cancer is higher than that in primary lung lesions, accompanied by higher TMB, possibly due to the ineffective presentation of tumor antigens resulting in the accumulation of mutations in lost HLA-I. Moreover, tumors with HLA-I LOH have reduced levels of CD8 T cell infiltration, suggesting impaired tumor antigen presentation impedes immune cytotoxicity. These phenomena contribute to the poorer efficacy of immunotherapy in such patients. In conclusion, HLA-I LOH may be one of the important mechanisms of immune escape in lung cancer brain metastases.

MicroRNA-522-3p promotes brain metastasis in non-small cell lung cancer by targeting Tensin 1 and modulating blood-brain barrier permeability

Brain metastases account for more than 50 % of intracranial central nervous system tumors. The blood-brain barrier (BBB) is mainly composed of endothelial cells, which exhibit low endocytosis and high efflux pumps. Although they are connected by continuous tight junctions and serve as a protective insulation, the BBB does not prevent the development of brain metastases from non-small cell lung cancer (NSCLC). Improving understanding on the mechanisms underlying the development of brain metastasis and the differential molecular characteristics relative to the primary tumor are therefore key in the treatment of brain metastases. This study evaluated the differential expression of miR-522-3p in NSCLC and brain metastases using the Gene Expression Omnibus database. NSCLC brain metastasis model was constructed to screen for cell lines that demonstrated high potential for brain metastasis; We also observed differential expression of miRNA-522-3p in the paraffin-embedded specimens of non-small cell lung cancer and brain metastases from our hospital. The molecular biological functions of miRNA-522-3p were verified using 5-ethynyl-2′-deoxyuridine (EdU) proliferation assay and Transwell invasion assays. RNA-seq was employed to identify downstream target proteins, and the dual-luciferase reporter assay confirmed Tensin 1 (TNS1), a protein that links the actin cytoskeleton to the extracellular matrix, as the downstream regulatory target protein. In vitro blood-brain barrier models and co-culture models were constructed to further identify the role of miRNA-522-3p and TNS1; the expression of BBB-related proteins (ZO-1 and OLCN) was also identified. In vivo experiments were performed to verify the effects of miRNA-522-3p on the time and incidence of NSCLC brain metastasis. The results showed significantly high expression in GSE51666; consistent results were obtained in brain metastasis cells and paraffin samples. RNA-seq combined with miRNA target protein prediction demonstrated TNS1 to be directly downstream of miR-522-3p and to be associated with cell proliferation and invasion. By regulating ZO-1 and OCLN expression, mi-522-3p/TNS1 may increase tumor cell penetration through the BBB while decreasing its permeability. In vivo, miR-522-3p was further demonstrated to significantly promote the formation of brain metastases. miR-522-3p/TNS1 can affect BBB permeability and encourage the growth of brain metastases by modifying the BBB TJ proteins. This axis offers new therapeutic targets for the prevention of brain metastasis.

Tertiary Lymphoid Structures in Brain Metastases of Lung Cancer: Prognostic Significance and Correlation With Clinical Outcomes.

The prognosis of patients with brain metastases (BMs) originating from lung cancer remains poor, despite advancements in treatment strategies. The role of tertiary lymphoid structures (TLSs) within the tumor immune microenvironment of BMs has not been extensively explored. This study utilized patient-derived clinical samples from 17 patients with histologically confirmed BMs of lung cancer, undergoing surgical resection. Immunohistochemistry was employed to analyze the presence and characteristics of TLS and tumor-infiltrating lymphocytes (TILs) within BM tissues, correlating these with clinical outcomes. TLSs, albeit in their immature form, were identified within BM tissues, distinguishing them from their mature counterparts in primary lung cancer tissues. A significant correlation between TLS density (but not TIL density) and improved postoperative survival was observed, underscoring the potential of TLS density as an independent prognostic marker. Furthermore, TLS density did not correlate with the Graded Prognostic Assessment (GPA) index, suggesting its unique prognostic value beyond conventional predictors. Our findings reveal the presence of TLSs in lung cancer-derived BMs and highlight their prognostic significance, independent of the GPA index. The identification of TLS within the unique central nervous system tumor microenvironment offers new insights into the immune landscape of BMs and suggests potential avenues for immunotherapeutic interventions targeting these structures to improve patient outcomes.

Hypofractionated stereotactic radiotherapy for brain metastases in lung cancer patients: dose‒response effect and toxicity

BackgroundLung cancer is a common cause of brain metastases, approximately 40% of patients with lung cancer will develop brain metastases at some point during their disease. Hypofractionated stereotactic radiotherapy (HSRT) has been demonstrated to be effective in controlling limited brain metastases. However, there is still no conclusive on the optimal segmentation of HSRT. The aim of our study was to explore the correlation between the HSRT dosage and its treatment effect and toxicity.MethodsA retrospective analysis was conducted on patients with non-small cell lung cancer (NSCLC) brain metastasis at Hangzhou Cancer Hospital from 1 January 2019 to 1 January 2021. The number of brain metastases did not exceed 10 in all patients and the number of fractions of HSRT was 5. The prescription dose ranges from 25 to 40 Gy. The Kaplan–Meier method was used for estimation of the localised intracranial control rate (iLC). Adverse radiation effects (AREs) were evaluated according to CTCAE 5.0. This study was approved by the Institutional Ethics Review Board of the Hangzhou Cancer Hospital (#73/HZCH-2022).ResultsForty eligible patients with a total of 70 brain metastases were included in this study. The 1-year iLC was 76% and 89% in the prescribed dose ≤ 30 Gy and > 30 Gy group, respectively (P < 0.05). For patients treated with HSRT combined with targeted therapy, immunotherapy and chemotherapy, the 1-year iLC was 89%, 100%, and 45%, respectively. No significant associations were observed between the number, maximum diameter, location, and type of pathology of brain metastases. The rate of all-grade AREs was 33%. Two patients who received a total dose of 40 Gy developed grade 3 headache, the rest of the AREs were grade 1–2.ConclusionsIncreasing the prescription dose of HSRT improves treatment effect but may also exacerbate the side effects. Systemic therapy might impact the iLC rate, and individualized treatment regimens need to be developed.