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Supplementary Video 5 shows a confocal time-lapse series, showing MDCK cells treated with 40 ug of K16ApoE, immediately after labeling with Calcein-AM (green), which indicates live cells, and Ethidium homodimer-1 (red), indicating dead cells.

Supplementary Video 2 shows sonographic visualization of the axial position of the heart of a NOD/SCID mouse injected with 1000 ug K16ApoE intravenously.

Supplementary Video 4 shows a confocal time-lapse series, showing MDCK cells treated with 20 ug of K16ApoE, immediately after labeling with Calcein-AM (green), which indicates live cells, and Ethidium homodimer-1 (red), indicating dead cells.

Supplementary Data - Figure Legends

Supplementary Video 1 shows sonographic visualization of the axial position of the heart of a NOD/SCID mouse injected with 9 mg/mL NaCl intravenously.

Supplementary Video 3 shows a confocal time-lapse series, showing a control sample of MDCK cells labeled with Calcein-AM (green), which indicates live cells, and Ethidium homodimer-1 (red), indicating dead cells.

Percentage growth change of individual nsNSCLC metastases during bevacizumab treatment

Supplementary Video 6 shows a confocal time-lapse series, showing MDCK cells treated with 80 ug of K16ApoE, immediately after labeling with Calcein-AM (green), which indicates live cells, and Ethidium homodimer-1 (red), indicating dead cells.

Patients with melanoma have a high risk of developing brain metastasis, which is associated with a dismal prognosis. During early stages of metastasis development, the blood–brain barrier (BBB) is likely intact, which inhibits sufficient drug delivery into the metastatic lesions. We investigated the ability of the peptide, K16ApoE, to permeabilize the BBB for improved treatment with targeted therapies preclinically. Dynamic contrast enhanced MRI (DCE-MRI) was carried out on NOD/SCID mice to study the therapeutic window of peptide-mediated BBB permeabilization. Further, both in vivo and in vitro assays were used to determine K16ApoE toxicity and to obtain mechanistic insight into its action on the BBB. The therapeutic impact of K16ApoE on metastases was evaluated combined with the mitogen-activated protein kinase pathway inhibitor dabrafenib, targeting BRAF mutated melanoma cells, which is otherwise known not to cross the intact BBB. Our results from the DCE-MRI experiments showed effective K16ApoE-mediated BBB permeabilization lasting for up to 1 hour. Mechanistic studies showed a dose-dependent effect of K16ApoE caused by induction of endocytosis. At concentrations above IC50, the peptide additionally showed nonspecific disturbances on plasma membranes. Combined treatment with K16ApoE and dabrafenib reduced the brain metastatic burden in mice and increased animal survival, and PET/CT showed that the peptide also facilitated the delivery of compounds with molecular weights as large as 150 kDa into the brain. To conclude, we demonstrate a transient permeabilization of the BBB, caused by K16ApoE, that facilitates enhanced drug delivery into the brain. This improves the efficacy of drugs that otherwise do not cross the intact BBB.

Time from randomization to new brain lesions in AVAiL Trial

Supplementary Materials shows supplementary methods, Supplementary Figures S1-S9 with legends and Supplementary Table 1. Supplementary Table 1: Mean Ve, Kep and AUC after DCE-MRI; Supplementary Figure S1: In vivo study design; Supplementary Figure S2: Blood smear from mice subjected to 1,000 µg K16ApoE; Supplementary Figure S3: In vitro cell viability: Supplementary Figure S4: Mechanistic studies of the in vitro effects of K16ApoE; Supplementary Figure S5: In vitro BBB model; Supplementary Figure S6: Biodistribution of 125I-K16ApoE; Supplementary Figure S7: Histopathological evaluation of tissue samples after long- and short-term treatment of NOD/SCID mice with the peptide; Supplementary Figure S8: In vivo treatment control experiment; Supplementary Figure S9: Mass spectrometry of treated and untreated brain tissue

Table containing all brain metastatic cell lines in the BrMPanel

Supplementary Figures S1-S7

Proteins binding with SChLAP1 sense and antisense

Spread of cancer to the brain remains an unmet clinical need in spite of the increasing number of cases among patients with lung, breast cancer, and melanoma most notably. Although research on brain metastasis was considered a minor aspect in the past due to its untreatable nature and invariable lethality, nowadays, limited but encouraging examples have questioned this statement, making it more attractive for basic and clinical researchers. Evidences of its own biological identity (i.e., specific microenvironment) and particular therapeutic requirements (i.e., presence of blood–brain barrier, blood–tumor barrier, molecular differences with the primary tumor) are thought to be critical aspects that must be functionally exploited using preclinical models. We present the coordinated effort of 19 laboratories to compile comprehensive information related to brain metastasis experimental models. Each laboratory has provided details on the cancer cell lines they have generated or characterized as being capable of forming metastatic colonies in the brain, as well as principle methodologies of brain metastasis research. The Brain Metastasis Cell Lines Panel (BrMPanel) represents the first of its class and includes information about the cell line, how tropism to the brain was established, and the behavior of each model in vivo. These and other aspects described are intended to assist investigators in choosing the most suitable cell line for research on brain metastasis. The main goal of this effort is to facilitate research on this unmet clinical need, to improve models through a collaborative environment, and to promote the exchange of information on these valuable resources.

Contains experimental therapies tested on brain metastatic cell lines and associated clinical trials

Oligonucleotide sets used, Plasmids used and Primer sets used in this study

Supplementary Materials and Methods

Authorship Change forms

PDF file - 287K, Automated signal quantification flow chart

MP4 file - 195K, SPION positive H2 cells at 24 hours

PDF file - 37K, Tumor take and mean number of tumors in the labeled 105, 5 x 105 and 106 groups and in the unlabeled 106 group at 4, 6 and 8 weeks post injection

PDF file - 241K, SPIONs do not influence cell migration and growth in vitro

PDF file - 355K, From human melanoma brain metastases to transfected cell line

PDF file - 47K, Includes movie legends

PDF file - 74K, More details on specific topics from main Materials and Methods, including BRAF mutational status, PPB staining, Scanning electron microscopy, Transmission electron microscopy, Histology and Immunohistochemistry data. Also includes supplementary reference.

Dysregulated iron metabolism is a hallmark of many cancers, including glioblastoma (GBM). However, its role in tumor progression remains unclear. Herein, we identified coatomer protein complex subunit zeta 1 (COPZ1) as a therapeutic target candidate which significantly dysregulated iron metabolism in GBM cells. Overexpression of COPZ1 was associated with increasing tumor grade and poor prognosis in glioma patients based on analysis of expression data from the publicly available database The Cancer Genome Atlas (P P P

Long non-coding RNAs (lncRNAs) play critical roles in tumour progression. Han et al. report that the lncRNA MIR22HG promotes glioma progression by generating miR-22-3p and miR-22-5p, and show that targeting MIR22HG/miR-22 with a novel small molecule inhibitor leads to inhibition of tumour growth in vivo., Long non-coding RNAs play critical roles in tumour progression. Through analysis of publicly available genomic datasets, we found that MIR22HG, the host gene of microRNAs miR-22-3p and miR-22-5p, is ranked among the most dysregulated long non-coding RNAs in glioblastoma. The main purpose of this work was to determine the impact of MIR22HG on glioblastoma growth and invasion and to elucidate its mechanistic function. The MIR22HG/miR-22 axis was highly expressed in glioblastoma as well as in glioma stem-like cells compared to normal neural stem cells. In glioblastoma, increased expression of MIR22HG is associated with poor prognosis. Through a number of functional studies, we show that MIR22HG silencing inhibits the Wnt/β-catenin signalling pathway through loss of miR-22-3p and -5p. This leads to attenuated cell proliferation, invasion and in vivo tumour growth. We further show that two genes, SFRP2 and PCDH15, are direct targets of miR-22-3p and -5p and inhibit Wnt signalling in glioblastoma. Finally, based on the 3D structure of the pre-miR-22, we identified a specific small-molecule inhibitor, AC1L6JTK, that inhibits the enzyme Dicer to block processing of pre-miR-22 into mature miR-22. AC1L6JTK treatment caused an inhibition of tumour growth in vivo. Our findings show that MIR22HG is a critical inducer of the Wnt/β-catenin signalling pathway, and that its targeting may represent a novel therapeutic strategy in glioblastoma patients.

Melanomas have a high potential to metastasize to the brain. Recent advances in targeted therapies and immunotherapies have changed the therapeutical landscape of extracranial melanomas. However, few patients with melanoma brain metastasis (MBM) respond effectively to these treatments and new therapeutic strategies are needed. Cabozantinib is a receptor tyrosine kinase (RTK) inhibitor, already approved for the treatment of non-skin-related cancers. The drug targets several of the proteins that are known to be dysregulated in melanomas. The anti-tumor activity of cabozantinib was investigated using three human MBM cell lines. Cabozantinib treatment decreased the viability of all cell lines both when grown in monolayer cultures and as tumor spheroids. The in vitro cell migration was also inhibited and apoptosis was induced by cabozantinib. The phosphorylated RTKs p-PDGF-Rα, p-IGF-1R, p-MERTK and p-DDR1 were found to be downregulated in the p-RTK array of the MBM cells after cabozantinib treatment. Western blot validated these results and showed that cabozantinib treatment inhibited p-Akt and p-MEK 1/2. Further investigations are warranted to elucidate the therapeutic potential of cabozantinib for patients with MBM.

BACKGROUND Melanoma has the highest propensity of any cancer to metastasize to the brain, with late-stage patients developing brain metastasis (MBM) in 40% of cases. Survival of patients with MBM is around 8 months with current therapies, illustrating the need for new treatments. MBM development is likely caused by molecular interactions between tumor cells and the brain, constituting the brain metastatic niche. miRNAs delivered by exosomes released from the primary tumor cells may play a role in niche establishment, yet the mechanisms are poorly understood. Here, the aim was to identify miRNAs released by exosomes from melanomas, which may be important in niche establishment and MBM progression. MATERIAL AND METHODS miRNAs in exosomes collected from human astrocytes, melanocytes, and MBM cell lines were profiled to determine differential expression. Functional in vitro validation was performed by cell growth and migration assays, cytokine arrays, qPCR and Western blots. Functional in vivo studies were performed after miR knockdown in MBM cell lines. An in silico docking study was performed to determine drugs that potentially inhibit transcription of miR-146a to impede MBM development. RESULTS miR-146a was the most upregulated miRNA in exosomes from MBM cells and was highly expressed in human and animal MBM samples. miR-146a mimics activated human astrocytes, shown by increased proliferation and migration, elevated expression of GFAP in vitro and in mouse brain tumor samples, and increased cytokine production. In animal studies, knockdown of miR-146 in MBM cells injected intracardially into mice reduced BM burden and increased animal survival. Based on the docking studies, deserpidine was found to be an effective inhibitor of MBM growth in vitro and in vivo. CONCLUSION miR-146a may play an important role in MBM development, and deserpidine is a promising candidate for clinical use.

Background Melanoma is one of the cancer types that have high potential to metastasise to the brain. Recent advances in targeted therapies and immunotherapies have changed the therapeutical landscape of extra-cranial melanoma. However, few patients with melanoma brain metastases (MBM) respond effectively to recent treatments and new therapeutic strategies are needed. Cabozantinib is a receptor tyrosine kinase (RTK) inhibitor, already approved by FDA for treatment of renal cell carcinoma, medullary thyroid cancer and hepatocellular carcinoma. The drug also targets several of the proteins which are known to be dysregulated in melanomas and may therefore have a potential role in melanoma treatment. In this study, we investigated the effect of cabozantinib on MBM cell growth and migration in vitro, and further identified its associated molecular components. Methods The anti-tumour activity of cabozantinib was investigated on three human MBM cell lines (H1, H3, H10) developed in our laboratory, through monolayer cell viability assays, tumoursphere experiments, cell migration assays, flow cytometry and caspase 3/7 apoptosis assays, RTK array screening and western blots (WB) to validate the array findings. Results Cabozantinib treatment decreased the viability of MBM cell lines both when grown in monolayer cultures and as tumour spheroids. The in vitro cell migration was also inhibited, and apoptosis was induced by cabozantinib. The phosphorylated RTKs p-PDGF-Rα, p-IGF-1R, p-MERTK and p-DDR1 were found to be downregulated in the p-RTK array of MBM cells after cabozantinib treatment. These results were validated with WB. Further, WB showed that cabozantinib treatment inhibited p-Akt and p-MEK 1/2. Conclusions For the first time, we show that cabozantinib effectively inhibits viability, growth and migration of MBM cells in vitro. Moreover, the drug induces apoptosis and downregulates the p-RTK p-PDGF-Rα, p-IGF-1R, p-MERTK and p-DDR1 in MBM cells. Further in vivo experiments are needed to bring cabozantinib forward as a potential, adjuvant treatment of patients with MBM.

Purpose: Long noncoding RNAs (lncRNA) have essential roles in diverse cellular processes, both in normal and diseased cell types, and thus have emerged as potential therapeutic targets. A specific member of this family, the SWI/SNF complex antagonist associated with prostate cancer 1 (SChLAP1), has been shown to promote aggressive prostate cancer growth by antagonizing the SWI/SNF complex and therefore serves as a biomarker for poor prognosis. Here, we investigated whether SChLAP1 plays a potential role in the development of human glioblastoma (GBM). Experimental Design: RNA-ISH and IHC were performed on a tissue microarray to assess expression of SChLAP1 and associated proteins in human gliomas. Proteins complexed with SChLAP1 were identified using RNA pull-down and mass spectrometry. Lentiviral constructs were used for functional analysis in vitro and in vivo. Results: SChLAP1 was increased in primary GBM samples and cell lines, and knockdown of the lncRNA suppressed growth. SChLAP1 was found to bind heterogeneous nuclear ribonucleoprotein L (HNRNPL), which stabilized the lncRNA and led to an enhanced interaction with the protein actinin alpha 4 (ACTN4). ACTN4 was also highly expressed in primary GBM samples and was associated with poorer overall survival in glioma patients. The SChLAP1–HNRNPL complex led to stabilization of ACTN4 through suppression of proteasomal degradation, which resulted in increased nuclear localization of the p65 subunit of NF-κB and activation of NF-κB signaling, a pathway associated with cancer development. Conclusions: Our results implicated SChLAP1 as a driver of GBM growth as well as a potential therapeutic target in treatment of the disease.

Patients with melanoma have a high risk of developing brain metastasis, which is associated with a dismal prognosis. During early stages of metastasis development, the blood–brain barrier (BBB) is likely intact, which inhibits sufficient drug delivery into the metastatic lesions. We investigated the ability of the peptide, K16ApoE, to permeabilize the BBB for improved treatment with targeted therapies preclinically. Dynamic contrast enhanced MRI (DCE-MRI) was carried out on NOD/SCID mice to study the therapeutic window of peptide-mediated BBB permeabilization. Further, both in vivo and in vitro assays were used to determine K16ApoE toxicity and to obtain mechanistic insight into its action on the BBB. The therapeutic impact of K16ApoE on metastases was evaluated combined with the mitogen-activated protein kinase pathway inhibitor dabrafenib, targeting BRAF mutated melanoma cells, which is otherwise known not to cross the intact BBB. Our results from the DCE-MRI experiments showed effective K16ApoE-mediated BBB permeabilization lasting for up to 1 hour. Mechanistic studies showed a dose-dependent effect of K16ApoE caused by induction of endocytosis. At concentrations above IC50, the peptide additionally showed nonspecific disturbances on plasma membranes. Combined treatment with K16ApoE and dabrafenib reduced the brain metastatic burden in mice and increased animal survival, and PET/CT showed that the peptide also facilitated the delivery of compounds with molecular weights as large as 150 kDa into the brain. To conclude, we demonstrate a transient permeabilization of the BBB, caused by K16ApoE, that facilitates enhanced drug delivery into the brain. This improves the efficacy of drugs that otherwise do not cross the intact BBB.

Proteolipid protein 2 (PLP2) is an integral ion channel membrane protein of the endoplasmic reticulum. The protein has been shown to be highly expressed in many cancer types, but its importance in glioma progression is poorly understood. Using publicly available datasets (Rembrandt, TCGA and CGGA), we found that the expression of PLP2 was significantly higher in high‐grade gliomas than in low‐grade gliomas. We confirmed these results at the protein level through IHC staining of high‐grade (n = 56) and low‐grade glioma biopsies (n = 16). Kaplan‐Meier analysis demonstrated that increased PLP2 expression was associated with poorer patient survival. In functional experiments, siRNA and shRNA PLP2 knockdown induced ER stress and increased apoptosis and autophagy in U87 and U251 glioma cell lines. Inhibition of autophagy with chloroquine augmented apoptotic cell death in U87‐ and U251‐siPLP2 cells. Finally, intracranial xenografts derived from U87‐ and U251‐shPLP2 cells revealed that loss of PLP2 reduced glioma growth in vivo. Our results therefore indicate that increased PLP2 expression promotes GBM growth and that PLP2 represents a potential future therapeutic target. publishedVersion

The Hippo signaling pathway controls organ development and is also known, in cancer, to have a tumor suppressing role. Within the Hippo pathway, we here demonstrate, in human gliomas, a functional interaction of a transmembrane protein, prostate transmembrane protein, androgen induced 1 (PMEPA1) with large tumor suppressor kinase 1 (LATS1). We show that PMEPA1 is upregulated in primary human gliomas. The PMEPA1 isoform PMEPA1a was predominantly expressed in glioma specimens and cell lines, and ectopic expression of the protein promoted glioma growth and invasion in vitro and in an orthotopic xenograft model in nude mice. In co-immunoprecipitation experiments, PMEPA1a associated with the Hippo tumor suppressor kinase LATS1. This interaction led to a proteasomal degradation of LATS1 through recruitment of the ubiquitin ligase, neural precursor cell expressed, developmentally downregulated 4 (NEDD4), which led to silencing of Hippo signaling. Alanine substitution in PMEPA1a at PY motifs resulted in failed LATS1 degradation. Targeting of a downstream component in the Hippo signaling pathway, YAP, with shRNA, interfered with the growth promoting activities of PMEPA1a in vitro and in vivo. In conclusion, the presented work shows that PMEPA1a contributes to glioma progression by a dysregulation of the Hippo signaling pathway and thus represents a promising target for the treatment of gliomas.

Brain metastasis (BM) is a major cause of cancer patient morbidity. Clinical magnetic resonance imaging (MRI) and positron emission tomography (PET) represent important resources to assess tumor progression and treatment responses. In preclinical research, anatomical MRI and to some extent functional MRI have frequently been used to assess tumor progression. In contrast, PET has only to a limited extent been used in animal BM research. A considerable culprit is that results from most preclinical studies have shown little impact on the implementation of new treatment strategies in the clinic. This emphasizes the need for the development of robust, high-quality preclinical imaging strategies with potential for clinical translation. This review focuses on advanced preclinical MRI and PET imaging methods for BM, describing their applications in the context of what has been done in the clinic. The strengths and shortcomings of each technology are presented, and recommendations for future directions in the development of the individual imaging modalities are suggested. Finally, we highlight recent developments in quantitative MRI and PET, the use of radiomics and multimodal imaging, and the need for a standardization of imaging technologies and protocols between preclinical centers.

INTRODUCTION It is well known that cancer patients with brain metastasis (BM) have a poor prognosis and current treatments are not effective. It has been shown that BM development is caused by molecular interactions between the tumor cells and the normal brain, constituting the so-called brain metastatic niche. In this respect, miRNAs delivered by exosomes released by the primary tumor cells seem to be an important factor in BM niche establishment yet the mechanisms behind this process is poorly understood. AIM The aim of this project was to determine miRNAs released by exosomes from melanomas that may be important in establishing the BM niche, and to validate these findings in vitro and in vivo. METHODS We performed a miRNA profiling on exosomes collected from 3 human melanoma BM cell lines and from human astrocytes and melanocytes, to determine the most important differently expressed miRNAs. Functional in vitro validation was performed by cell growth and migration assays, cytokine arrays, qPCR and Western blots. Functional in vivo studies were performed after miR-knockdown in BM cell lines, in an experimental animal/tumor model. RESULTS AND DISCUSSION The miRNA profiling showed that miR-146a was by far the most differentially upregulated miRNA in exosomes from melanoma BM cell lines, compared to exosomes from normal cells. Mir-146a mimics activated human astrocytes, shown by increased proliferation and migration, elevated expression of GFAP in vitro and in mouse brain tumor samples, and increased cytokine production. These effects were reversed by adding anti-miR-146a to the experiments. In animal studies, knockdown of miR-146 in melanoma BM cells injected intracardially into nod/scid mice resulted in a significant reduction in BM burden, compared to wild type cells, and increased animal survival. CONCLUSIONS Inhibition of miR-146a reduces activation of the BM niche, leading to inhibition of BM development.