Brain Metastatic Lung Cancer Research Articles

HIF2A mediates lineage transition to aggressive phenotype of cancer-associated fibroblasts in lung cancer brain metastasis

ABSTRACT Brain metastasis is the most devasting form of lung cancer. Recent studies highlight significant differences in the tumor microenvironment (TME) between lung cancer brain metastasis (LCBM) and primary lung cancer, which contribute significantly to tumor progression and drug resistance. Cancer-associated fibroblasts (CAFs) are the major component of pro-tumor TME with high plasticity. However, the lineage composition and function of CAFs in LCBM remain elusive. By reanalyzing single-cell RNA sequencing (scRNA-seq) data (GSE131907) from lung cancer patients with different stages of metastasis comprising primary lesions and brain metastasis, we found that CAFs undergo distinctive lineage transition during LCBM under a hypoxic situation, which is directly driven by hypoxia-induced HIF-2α activation. Transited CAFs enhance angiogenesis through VEGF pathways, trigger metabolic reprogramming, and promote the growth of tumor cells. Bulk RNA sequencing data was utilized as validation cohorts. Multiplex immunohistochemistry (mIHC) assay was performed on four paired samples of brain metastasis and their primary lung cancer counterparts to validate the findings. Our study revealed a novel mechanism of lung cancer brain metastasis featuring HIF-2α-induced lineage transition and functional alteration of CAFs, which offers potential therapeutic targets.

EZH2 G553C significantly increases the risk of brain metastasis from lung cancer due to salt bridge instability

BackgroundThe incidence and mortality of lung cancer is the highest in China and the world. Brain is the most common distant metastasis site of lung cancer. Its transfer mechanism and predictive biomarkers are still unclear. EZH2 participates in the catalysis of transcriptional inhibition complex, mediates chromatin compactness, leads to the silencing of its downstream target genes, participates in the silencing of multiple tumor suppressor genes, and is related to cell proliferation, apoptosis and cycle regulation. In physiology, EZH2 has high activity in stem cells or progenitor cells, inhibits genes related to cell cycle arrest and promotes self-renewal. To detect the expression and mutation of EZH2 gene in patients with brain metastasis of lung cancer, and provide further theoretical basis for exploring the pathogenesis of brain metastasis of lung cancer and finding reliable biomarkers to predict brain metastasis of lung cancer.MethodsThis study investigated susceptible genes for brain metastasis of lung cancer. The second-generation sequencing technology was applied to screen the differential genes of paired samples (brain metastasis tissues, lung cancer tissues and adjacent tissues) of lung cancer patients with brain metastasi.ResultsIt revealed that there was a significant difference in the G553C genotype of EZH2 between lung cancer brain metastasis tissues and lung cancer tissues (p = 0.045). The risk of lung cancer brain metastasis in G allele carriers was 2.124 times higher than that in C allele carriers. Immunohistochemistry showed that compared with lung cancer patients and lung cancer patients with brain metastasis, the expression level of EZH2 in lung cancer tissues of lung cancer patients was significantly higher than that in adjacent lung tissues (p < 0.0001), and higher than that in brain metastasis tissues (p = 0.0309). RNA in situ immunohybridization showed that EZH2 mRNA expression was gradually high in lung cancer adjacent tissues, lung cancer tissues and lung cancer brain metastasis tissues.ConclusionsEZH2 G553C polymorphism contributes to the prediction of brain metastasis of lung cancer, in which G allele carriers are more prone to brain metastasis.

Abstract 7362: Integrated analysis of scRNAseq and spatial omics in brain metastatic lung cancer tumor tissue

Abstract Spatial omics technologies have made significant advances in recent years, improving our understanding of the spatial localization of cells and intercellular interactions. Intercellular interactions are essential for maintaining proper tissue function and homeostasis, and dysregulation of these interactions can contribute to various diseases, including cancer and autoimmune disorders. Ligand proteins, one of the signaling molecules responsible for cell-cell interactions, bind to cell surface receptors and trigger intracellular signaling pathways. The effective range of ligand signaling, i.e. the extent to which a cell spatially and directly transmits information via the ligand, has not been systematically studied, although it may determine the occurrence of cell-cell interactions. The authors have previously developed methodologies combining spatial transcriptomics and single-cell RNA sequencing to analyze intercellular interactions at the single-cell level in spatial dimensions. Additionally, we have devised a technique to model the spatial diffusion of ligands from spatial transcriptomics and estimate the spatial range of ligand action. In this study, we used these developed methods to elucidate events in the tumor microenvironment of brain metastatic lung cancer tissue. Specifically, an integrated analysis of metastatic brain tumor samples was performed using visium and single-cell data from the same patient. The results suggest the presence of a heterogeneous microglial subpopulation, including clusters enriched in cytokines and chemokines for angiogenesis and wound healing, clusters associated with immune tolerance via IL-10 signaling, clusters enriched in gene sets related to phagocytosis, antigen processing, and antigen presentation, and clusters related to clearance of pathogens and residues. The presence of homogeneous microglial subpopulations was suggested. Furthermore, these subpopulations exhibited different spatial distributions, suggesting that they interact with surrounding cancer cells through different mechanisms. Citation Format: Haruka Hirose, Takahiro Tsuji, Yasuhiro Kojima, Akihiko Yoshizawa, Yoshiki Arakawa, Hiroaki Ozasa, Hiroaki Wake, Teppei Shimamura. Integrated analysis of scRNAseq and spatial omics in brain metastatic lung cancer tumor tissue [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7362.

Expression of Concern: Fate and Efficacy of Engineered Allogeneic Stem Cells Targeting Cell Death and Proliferation Pathways in Primary and Brain Metastatic Lung Cancer.

Expression of Concern: Fate and Efficacy of Engineered Allogeneic Stem Cells Targeting Cell Death and Proliferation Pathways in Primary and Brain Metastatic Lung Cancer.

Predictive importance of systemic inflammation response index in de novo brain metastatic small cell lung cancer patients

Aims: The subtype of lung cancer, known as small cell lung cancer (SCLC), tends to have a highly fatal course, especially in advanced stages. In particular, the overall survival durations further decrease in cases of brain metastases in SCLC. There is increasing evidence for the role of systemic inflammation parameters in predicting cancer prognosis, and they appear likely to become potential target markers for clinical treatments in the future. We aimed to evaluate the systemic inflammation response index (SIRI), a novel inflammatory laboratory marker that could predict long-term survival and serve as a potential target marker for clinical treatment, in patients with de novo brain metastatic small cell lung carcinoma (DNBM SCLC)."&#x0D; Methods: Clinicopathological features of adult patients diagnosed with DNBM SCLC were recorded from the patient registry of the hospital. Patients without medical records were not included in the study. Investigations were carried out to assess the prognostic effect of the SIRI parameter in predicting the 12-month overall survival (OS12) in DNBM SCLC patients, by determining a cut-off value and conducting appropriate statistical analyses, considering p-values (

Anti-Cancer Effect of Neural Stem Cells Transfected with Carboxylesterase and sTRAIL Genes in Animals with Brain Lesions of Lung Cancer.

A metastatic brain tumor is the most common type of malignancy in the central nervous system, which is one of the leading causes of death in patients with lung cancer. The purpose of this study is to evaluate the efficacy of a novel treatment for metastatic brain tumors with lung cancer using neural stem cells (NSCs), which encode rabbit carboxylesterase (rCE) and the secretion form of tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL). rCE and/or sTRAIL were transduced in immortalized human fetal NSCs, HB1.F3. The cytotoxic effects of the therapeutic cells on human lung cancer cells were evaluated in vitro with the ligands and decoy receptor expression for sTRAIL in the presence of CPT-11. Human NSCs encoding rCE (F3.CE and F3.CE.sTRAIL) significantly inhibited the growth of lung cancer cells in the presence of CPT-11 in vitro. Lung cancer cells were inoculated in immune-deficient mice, and therapeutic cells were transplanted systematically through intracardiac arterial injection and then treated with CPT-11. In resting state, DR4 expression in lung cancer cells and DcR1 in NSCs increased to 70% and 90% after CPT-11 addition, respectively. The volumes of the tumors in immune-deficient mice were reduced significantly in mice with F3.CE.sTRAIL transplantation and CPT-11 treatment. The survival was also significantly prolonged with treatment with F3.sTRAIL and F3.CE plus CPT-11 as well as F3.CE.sTRAIL plus CPT-11. NSCs transduced with rCE and sTRAIL genes showed a significant anti-cancer effect on brain metastatic lung cancer in vivo and in vitro, and the effect may be synergistic when rCE/CPT-11 and sTRAIL are combined. This stem-cell-based study using two therapeutic genes of different biological effects can be translatable to clinical application.

Fate and Efficacy of Engineered Allogeneic Stem Cells Targeting Cell Death and Proliferation Pathways in Primary and Brain Metastatic Lung Cancer.

Primary and metastatic lung cancer is a leading cause of cancer-related death and novel therapies are urgently needed. Epidermal growth factor receptor (EGFR) and death receptor (DR) 4/5 are both highly expressed in primary and metastatic non-small cell lung cancer (NSCLC); however, targeting these receptors individually has demonstrated limited therapeutic benefit in patients. In this study, we created and characterized diagnostic and therapeutic stem cells (SC), expressing EGFR-targeted nanobody (EV) fused to the extracellular domain of death DR4/5 ligand (DRL) (EVDRL) that simultaneously targets EGFR and DR4/5, in primary and metastatic NSCLC tumor models. We show that EVDRL targets both cell surface receptors, and induces caspase-mediated apoptosis in a broad spectrum of NSCLC cell lines. Utilizing real-time dual imaging and correlative immunohistochemistry, we show that allogeneic SCs home to tumors and when engineered to express EVDRL, alleviate tumor burden and significantly increase survival in primary and brain metastatic NSCLC. This study reports mechanistic insights into simultaneous targeting of EGFR- and DR4/5 in lung tumors and presents a promising approach for translation into the clinical setting.

Haplotype-GGGT in long non-coding RNA MALAT1 inhibits brain metastatic lung cancer and lymph nodes of lung cancer via the MALAT1/miR-328/KATNB1.

The up-regulation of Katanin P8 has been reported to be correlated with a larger tumor size and lymph node metastasis in non-small-cell lung cancer (NSCLC) patients. And lncRNA MALAT1 was demonstrated to promote the proliferation of chronic myeloid leukemia cells via modulating miR-328. 135 lung cancer patients were divided into 6 groups according to their genotypes of MALAT1. The expression of KATNB1 was negatively correlated with the GGGT genotype of MALAT1. Decreased lymph node size and tumor size of brain metastatic lung were observed in patients with GGGT genotype of MALAT1. The luciferase activities of MALAT1 and KATNB1 were remarkably suppressed by miR-328 in A549 and H460. And the down-regulation of MALAT1 or up-regulation of miR-328 significantly repressed the KATNB1 expression in A549 and H460 cells. MALAT1 expression was reduced in patients carrying haplotype GGGT. A signaling pathway of MALAT1/miR-328/KATNB1 was established to explain the down-regulation of KATNB1 mRNA in patients carrying haplotype GGGT and reduced lymph node size in lung cancer and tumor size in brain metastatic lung cancer.

Added survival benefit of whole brain radiotherapy in brain metastatic non-small cell lung cancer: Development and external validation of an individual prediction model.

The heterogeneous survival benefit of whole brain radiotherapy (WBRT) in brain metastatic non-small cell lung cancer (NSCLC) was prospectively evidenced in the Quality of Life after Treatment for Brain Metastases (QUARTZ) trial, resulting in inconsistent guideline recommendations and diverse clinical practices for giving WBRT. The objective of this study was to develop and externally validate an individual prediction model to demonstrate the added survival benefit of WBRT to assist decision making when giving WBRT is undetermined. For model development, we collected 479 brain metastatic NSCLC patients unfit for surgery or stereotactic radiotherapy techniques at Siriraj Hospital. Potential predictors were age, sex, performance status, histology, genetic mutation, neurological symptoms, extracranial disease, previous systemic treatment, measurable lesions, further systemic treatment, and WBRT. Cox proportional hazard regression was used for survival analysis. We used multiple imputations to handle missing data and a backward selection method for predictor selection. Bootstrapping was used for internal validation, while model performance was assessed with discrimination (c-index) and calibration prediction accuracy. The final model was transformed into a nomogram and a web-based calculator. An independent cohort from Sawanpracharak Hospital was used for external validation. In total, 452 patients in the development cohort died. The median survival time was 4.4 (95% CI, 3.8-4.9) months, with 5.1 months for patients who received WBRT and 2.3 months for those treated with optimal supportive care (OSC). The final model contained favorable predictors: female sex, KPS > 70, receiving additional systemic treatment, and WBRT. Having active extracranial disease, experiencing neurological symptoms, and receiving previous systemic treatment were adverse predictors. After optimism correction, the apparent c-index dropped from 0.71 (95% CI, 0.69-0.74) to 0.70 (95% CI, 0.69-0.73). The predicted and observed values agreed well in all risk groups. Our model performed well in the external validation cohort, with a c-index of 0.66 (95% CI, 0.59-0.73) and an acceptable calibration. This model (https://siriraj-brainmetscore.netlify.app/) predicted the added survival benefit of WBRT for individual brain metastatic NSCLC patients, with satisfactory performance in the development and validation cohorts. The results certify its value in aiding treatment decision-making when the administration of WBRT is unclear.

An in silico comparative transcriptome analysis identifying hub lncRNAs and mRNAs in brain metastatic small cell lung cancer (SCLC)

Small cell lung cancer (SCLC) is a particularly lethal subtype of lung cancer. Metastatic lung tumours lead to most deaths from lung cancer. Predicting and preventing tumour metastasis is crucially essential for patient survivability. Hence, in the current study, we focused on a comprehensive analysis of lung cancer patients' differentially expressed genes (DEGs) on brain metastasis cell lines. DEGs are analysed through KEGG and GO databases for the most critical biological processes and pathways for enriched DEGs. Additionally, we performed protein–protein interaction (PPI), GeneMANIA, and Kaplan–Meier survival analyses on our DEGs. This article focused on mRNA and lncRNA DEGs for LC patients with brain metastasis and underlying molecular mechanisms. The expression data was gathered from the Gene Expression Omnibus database (GSE161968). We demonstrate that 30 distinct genes are up-expressed in brain metastatic SCLC patients, and 31 genes are down-expressed. All our analyses show that these genes are involved in metastatic SCLC. PPI analysis revealed two hub genes (CAT and APP). The results of this article present three lncRNAs, Including XLOC_l2_000941, LOC100507481, and XLOC_l2_007062, also notable mRNAs, have a close relation with brain metastasis in lung cancer and may have a role in the epithelial-mesenchymal transition (EMT) in tumour cells.

Unusual finding in a diagnostic bronchoscopy of a patient with brain metastatic lung cancer

Unusual finding in a diagnostic bronchoscopy of a patient with brain metastatic lung cancer

Unusual finding in a diagnostic bronchoscopy of a patient with brain metastatic lung cancer

Swallowing disorders are common manifestations in patients with advanced lung cancer, this paper describes a rare clinical case of a foreign body (chicken bone) accidently found in the lumen of the left upper lobe bronchus during bronchoscopy. A 41 year- old man, with smoking history of 20 PA presented to our department with paraplegia and left arm paresis, he complained over 6 months from dyspnea, increasing posterior chest pain and persistent dry coughing. He had a history of swallowing disorders and difficulties with shocking episode passed unnoticed. The patient was apyretic but presented weight loss and weakness. On physical examination, he had a digital hippocratism, a WHO performance status was at 4 and there were diffuse snoring rales on pulmonary auscultation. The body CT scan showed a voluminous left upper mediastinal tumor involving the left upper lobe and the left apical pyramidal lobe, this tumor was extended to vascular elements and to the dorsal spine. The cerebral CT scan showed discreetly a compressive right parietal process measuring 3cm*3cm. The flexible bronchoscopy has been performed showing an extrinsic compression of the posterior wall of the trachea, a blood clot removed showing a piece of chicken bone presented in the lumen of the anterior segmental bronchus. The patient was referred to the oncology department for palliative treatment, after being diagnosed as lung adenocarcinoma by a CT guided lung biopsy. This is the first paper reported an accidently discovery of bronchial foreign body during bronchoscopy in a patient with stage IVB lung cancer. Dysphagia has been reported as common manifestation in patients with advanced lung cancer due to underlying mediastinal disease and brainstem lesions metastasis, it is considered as a disorder which may increase the risk of morbi-mortality and has a potential of life-threatening.

A nomogram for predicting overall survival rate in patients with brain metastatic non-small cell lung cancer.

The purpose was to develop a nomogram for the prediction of the 1- and 2-year overall survival (OS) rates in patients with brain metastatic non-small cell lung cancer (BMNSCLC).Patients were collected from the Surveillance Epidemiology and End Results program (SEER) and classified into the training and validation groups. Several independent prognostic factors identified by statistical methods were incorporated to establish a predictive nomogram. The concordance index (C-index), the area under the receiver operating characteristics curve (AUC), and calibration curve were applied to estimate predictive ability of the nomogram. To compare the clinical practicability of the nomogram and TNM staging system by decision curve analysis (DCA).A total of 24,164 eligible patients were collected and assigned into the training (n = 16,916) and validation groups (n = 7248). Based on the prognostic factors, we developed a nomogram with good discriminative ability. The C-indices for training and validation group were 0.727 and 0.728. The AUCs of 1- and 2-year OS rates were both 0.8, and the calibration curves also demonstrated good performance of the nomogram. DCA illustrated that the nomogram provided clinical net benefit compared with the TNM staging system.We developed a predictive nomogram for more accurate and comprehensive prediction of OS in BMNSCLC patients, which can be a useful and convenient tool for clinicians to make proper clinical decisions, and adjust follow-up management strategies.

Immune suppressive microenvironment in brain metastatic non-small cell lung cancer: comprehensive immune microenvironment profiling of brain metastases versus paired primary lung tumors (GASTO 1060)

ABSTRACT Lung cancer is one of the most common causes of brain metastases and is always associated with poor prognosis. We investigated the immunophenotypes of primary lung tumors and paired brain metastases, as well as immunophenotypes in the synchronous group (patients with brain metastases upon initial diagnosis) and metachronous group (patients developed brain metastases during the course of their disease). RNA sequencing of eighty-six samples from primary lung tumors and paired brain metastases of 43 patients was conducted to analyze the tumor immune microenvironment. Our data revealed that matched brain metastases compared with primary lung tumors exhibited reduced tumor infiltrating lymphocytes (TILs), a higher fraction of neutrophils infiltration, decreased scores of immune-related signatures, and a lower proportion of tumor microenvironment immune type I (high PD-L1/high CD8A) tumors. Additionally, we found a poor correlation of PD-L1 expression between paired brain metastases and primary lung tumors. In addition, gene set enrichment analysis (GSEA) showed that some gene sets associated with the immune response were enriched in the metachronous group, while other gene sets associated with differentiation and metastasis were enriched in the synchronous group in the primary lung tumors. Moreover, the tumor immune microenvironment between paired brain metastases and primary lung tumors displayed more differences in the metachronous group than in the synchronous group. Our work illustrates that brain metastatic tumors are more immunosuppressed than primary lung tumors, which may help guide immunotherapeutic strategies for NSCLC brain metastases.

Cathepsin F and Fibulin-1 as novel diagnostic biomarkers for brain metastasis of non-small cell lung cancer

BackgroundThe lack of non-invasive methods for detection of early micro-metastasis is a major cause of the poor prognosis of non-small cell lung cancer (NSCLC) brain metastasis (BM) patients. Herein, we aimed to identify circulating biomarkers based on proteomics for the early diagnosis and monitoring of patients with NSCLC BM.MethodsUpregulated proteins were detected by secretory proteomics in the animal-derived high brain metastatic lung cancer cell line. A well-designed study composed of three independent cohorts was then performed to verify these blood-based protein biomarkers: the serum discovery and verification cohorts (n = 80; n = 459), and the tissue verification cohort (n = 76). Logistic regression was used to develop a diagnostic biomarker panel. Model validation cohort (n = 160) was used to verify the stability of the constructed predictive model. Changes in serum Cathepsin F (CTSF) levels of patients were tracked to monitor the treatment response. Progression-free survival (PFS) and overall survival (OS) were analysed to assess their prognostic relevance.ResultsCTSF and Fibulin-1 (FBLN1) levels were specifically upregulated in sera and tissues of patients with NSCLC BM compared with NSCLC without BM and primary brain tumour. The combined diagnostic performance of CTSF and FBLN1 was superior to their individual ones. CTSF serum changes were found to reflect the therapeutic response of patients with NSCLC BM and the trends of progression were detected earlier than the magnetic resonance imaging changes. Elevated expression of CTSF in NSCLC BM tissues was associated with poor PFS, and was found to be an independent prognostic factor.ConclusionsWe report a novel blood-based biomarker panel for early diagnosis, monitoring of therapeutic response, and prognostic evaluation of patients with NSCLC BM.

118TiP A multicenter, randomized, double-blind, placebo-controlled phase III trial of camrelizumab plus chemotherapy with or without radiation therapy (RT) as first-line treatment for patients with brain metastatic non-small cell lung cancer (BM-NSCLC; CTONG2003): Trial in progress

At diagnosis, 10%-15% NSCLC patients have brain metastases. BM-NSCLC suffer worse prognosis. For BM-NSCLC, local therapies, e.g., surgery and radiation therapy, are the mainstream of treatment. Immunotherapy combined with or without chemotherapy is first-line standard of care for NSCLC. Immunotherapy showed trends for benefit in BM-NSCLC and a synergistic effect with radiation therapy. However, there is a lack of high-quality evidence on additional immunotherapy on chemotherapy for BM-NSCLC. The present phase III trial aims to confirm camrelizumab, an anti-programmed cell death protein-1 antibody, plus chemotherapy with or without stereotactic or whole brain RT as first-line treatment for BM-NSCLC without driver gene mutation.

Chuanxiong Rhizoma inhibits brain metastasis of lung cancer through multiple active ingredients acting on multiple targets, pathways and biological functions

To explore the molecular mechanism mediating the inhibitory effect of Chuanxiong Rhizoma against brain metastasis of lung cancer using network pharmacology methods and molecular docking. The chemical components of Chuanxiong Rhizoma and their targets were obtained through the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database. The relevant targets for brain metastasis of lung cancer were screened using the GeneCards database. Clusterpro-filerR package was used to perform GO and KEGG enrichment analysis. Cytoscape and STRING database were used to construct the "active ingredient-target-disease" network and protein-protein interaction (PPI) network of Chuanxiong Rhizoma. The core components of Chuanxiong Rhizoma and their targets in the treatment of lung cancer brain metastasis were screened based on the topological parameters, and the results were verified using molecular docking and in Chuanxiong extract- treated human lung cancer PC9 cells by detecting the core target with Western blotting. Forty-eight active ingredients of Chuanxiong Rhizoma including (Z)-ligustilide, butylphthalide, oleic acid, and myricetone were screened, which target 49 proteins including INS, BDNF, FOS, VEGFA, PTGS2, ESR1, MAPK14, and PTGS1. These proteins participated in 57 biological functions such as nuclear receptor activity, ligand activation, and transcription factor activity, involving 40 signaling pathways such as prolactin signaling pathway, breast cancer, and etrogen signaling. The results of molecular docking showed that myricetone, butylphthalide, 4-hydroxy-3 butylphthalide, (Z)-ligustilide, and ligustalide-E, among others, had strong affinities to 7 cores targets including BDNF, FOS, PTGS2, and MAPK14. In PC9 cells, treatment with Chuanxiong Rhizoma extract resulted in significant reductions in the phosphorylation levels of PI3K, Akt and VEGF (P < 0.01). Chuanxiong Rhizoma contains multiple active ingredients against brain metastasis lung cancer, and these ingredients act on multiple targets involving multiple signal pathways and biological functions.

BSCI-05. ABL2-HSF1-E2F signaling axis promotes lung adenocarcinoma brain metastasis

Brain metastases are the most common intracranial tumors in adults and are associated with increased patient morbidity and mortality. Limited therapeutic options are currently available for the treatment of brain metastasis. We have identified an actionable signaling pathway utilized by metastatic tumor cells whereby the transcriptional regulator Heat Shock Factor 1 (HSF1) drives a transcriptional program, divergent from its canonical role as the master regulator of the heat shock response, leading to enhanced expression of a subset of E2F transcription factor family gene targets. We showed that HSF1 is required for survival and outgrowth by metastatic lung cancer cells in the brain parenchyma. Unexpectedly, we identified the ABL2 tyrosine kinase as an upstream regulator of HSF1 protein expression, and showed that the Src-homology 3 (SH3) domain of ABL2 directly interacts with HSF1 protein at a non-canonical, proline-independent SH3 interaction motif. Importantly, knockdown of ABL2 impairs expression of HSF1 protein and HSF1-E2F transcriptional gene targets. Notably, we found that pharmacologic inhibition of the ABL kinases using selective ABL allosteric inhibitors, but not ATP-competitive inhibitors, ablates the physical interaction between ABL2 and HSF1, leading to markedly decreased expression of HSF1, E2F1 and E2F8 proteins in brain-metastatic lung cancer cells, and depletion of HSF1-E2F transcriptional targets. These findings highlight potential differences affecting intra- and inter-molecular protein-protein interactions induced by allosteric versus ATP-competitive kinase inhibitors that have important therapeutic implications. Importantly, the targetable nature of the ABL2-HSF1-E2F signaling network identifies ABL allosteric inhibitors as a potentially effective therapy for the treatment of metastatic lung cancers characterized by high expression of HSF1.

Evaluation of Oxidative Stress Biomarkers in Brain Metastatic and Non-Metastatic Lung Cancer Patients with Different Cell Types.

Oxidative stress that leads to an imbalanced prooxidant/antioxidant status can be a critical factor affecting lung cancer etiopathology. The antioxidant system provides primary protection under oxidative stress. The purpose of the study was to investigate the serum antioxidant system status in brain metastatic and non-metastatic lung cancer patients with different cell types. In this prospective study, 33 patients with lung cancer metastasis (metastatic patient group), 36 lung cancer patients (non-metastatic patient group), and 25 healthy control groups were included. Enzymatic (Superoxide Dismutase, SOD; Glutathione Peroxidase, GPX; and Glutathione Reductase, GR) and non-enzymatic (Glutathione, GSH) antioxidant system biomarkers with Thiobarbituric Acid Reactive Substances (TBARS) levels were studied in the serum samples of the control and patient groups. The oxidative stress biomarkers were measured spectrophotometrically. SOD activity increased though TBARS levels and GR activity decreased in both patient groups compared to the control. GPX activity increased only in the non-metastatic group. Antioxidant biomarkers varied between small cell and non-small cell group patients. GR activity and GSH levels were significantly higher in the non-metastatic group compared to the metastatic group. Correlations were also found between antioxidant parameters in the non-metastatic group. It was emphasized the imbalanced antioxidant system in the duration of the disease is related to not only cell type but also the metastatic structure. This is the preliminary study exhibiting the contribution of antioxidant imbalance in different subtypes with varied prognosis and behavior of lung cancer in the presence of brain metastasis. Therefore, oxidative stress biomarkers can serve as a useful tool to get information about the progression of lung cancer. Thus, it may provide fundamental data for further cancer research when considering the diagnosis of the disease.

The ABL2 kinase regulates an HSF1-dependent transcriptional program required for lung adenocarcinoma brain metastasis

Brain metastases are the most common intracranial tumors in adults and are associated with increased patient morbidity and mortality. Limited therapeutic options are currently available for the treatment of brain metastasis. Here, we report on the discovery of an actionable signaling pathway utilized by metastatic tumor cells whereby the transcriptional regulator Heat Shock Factor 1 (HSF1) drives a transcriptional program, divergent from its canonical role as the master regulator of the heat shock response, leading to enhanced expression of a subset of E2F transcription factor family gene targets. We find that HSF1 is required for survival and outgrowth by metastatic lung cancer cells in the brain parenchyma. Further, we identify the ABL2 tyrosine kinase as an upstream regulator of HSF1 protein expression and show that the Src-homology 3 (SH3) domain of ABL2 directly interacts with HSF1 protein at a noncanonical, proline-independent SH3 interaction motif. Pharmacologic inhibition of the ABL2 kinase using small molecule allosteric inhibitors, but not ATP-competitive inhibitors, disrupts this interaction. Importantly, knockdown as well as pharmacologic inhibition of ABL2 using allosteric inhibitors impairs expression of HSF1 protein and HSF1-E2F transcriptional gene targets. Collectively, these findings reveal a targetable ABL2-HSF1-E2F signaling pathway required for survival by brain-metastatic tumor cells.