Laminin Subunit Alpha-4 and Osteopontin Are Glioblastoma-Selective Secreted Proteins That Are Increased in the Cerebrospinal Fluid of Glioblastoma Patients

Comparative proteomic profiling of glioblastoma and healthy brain cell-derived extracellular vesicles reveals enrichment of cancer-associated proteins

Extracellular vesicles (EVs)-mediated cellular communication plays a role in cancer development and progression. This study focuses on identifying glioblastoma-specific EV protein markers through a comparative mass spectrometry bottom-up proteomic analysis of the LN-229 cell line and human neurons, astrocytes, and endothelial brain cells (HEBCs) using timsTOF Pro 2 instrument. The statistically significant upregulated proteins with fold change greater than 2 in the glioblastoma-derived EVs were clustered based on physical and functional interactions using the STRING database and analyzed using Gene Ontology enrichment. LN229-derived EVs contained an average of 2635 proteins, while human astrocytes, neurons, and HEBC encapsulated 2647, 716, and 2285 proteins, respectively. NanoParticle Tracking Analysis indicated that glioblastoma-derived EVs exhibited greater size variability compared to EVs from healthy cells. Statistical analysis identified 25 statistically significant proteins with increased levels in LN229 EVs relative to at least two healthy cell lines suggesting their potential as glioblastoma markers. Functional clustering using the STRING database and GO analysis indicated involvement in epigenetic regulation, metastasis, angiogenesis, and protein folding. Post-translational modification analysis identified a subset of 17 proteins unique to the cancer-derived EVs involved in chromatin regulation, extracellular matrix remodeling, and basement membrane organization pathways, highlighting their role in tumor progression.

The role of laminins in cancer pathobiology: a comprehensive review

Laminins (LMs) are a family of heterotrimeric glycoproteins that form the structural foundation of basement membranes (BM). By acting as molecular bridges between cells and the extracellular matrix (ECM) through integrins and other surface receptors, they regulate key cellular signals that influence cell behavior and tissue architecture. Despite their physiological importance, our understanding of the role of LMs in cancer pathobiology remains fragmented. In this article, we review the diverse functions of LMs in promoting cancer cell proliferation, adhesion, and migration-critical steps in cancer metastasis. Beyond their direct effects on tumor cells, LMs influence stromal interactions and modulate tumor microenvironment dynamics, affecting processes such as angiogenesis, immune cell infiltration, cancer-associated fibroblast activation, and immune evasion. Understanding the complex roles of LMs in cancer biology, as well as their differential expression patterns in malignancies, could provide new diagnostic tools for predicting disease outcomes and pave the way for innovative therapeutic strategies, such as targeting LM-receptor interactions or modulating ECM dynamics to impede tumor growth and metastasis.

New Anti-Angiogenic Therapy for Glioblastoma With the Anti-Depressant Sertraline

BACKGROUND AND AIMS

Anti-angiogenic therapies prolong patient survival in some malignancies but not glioblastoma. We focused on the relationship between the differentiation of glioma stem like cells (GSCs) into tumor derived endothelial cells (TDECs) and, anti-angiogenic therapy resistance. Especially we aimed to elucidate the mechanisms of drug resistance of TDECs to anti-angiogenic inhibitors and identify novel anti-angiogenic drugs with clinical applications.

RESULTS

The mouse GSCs, 005, were differentiated into TDECs under hypoxic conditions, and TDECs had endothelial cell characteristics independent of the vascular endothelial growth factor (VEGF) pathway. In vivo, inhibition of the VEGF pathway had no anti-tumor effect and increased the percentage of TDECs in the 005 mouse model. Novel anti-angiogenic drugs for glioblastoma were evaluated using a tube formation assay and a drug repositioning strategy with existing blood-brain barrier permeable drugs. Drug screening revealed that the antidepressant sertraline inhibited tube formation of TDECs. Sertraline was administered to differentiated TDECs in vitro and 005 mouse models in vivo to evaluate genetic changes by RNA-Seq and tumor regression effects by immunohistochemistry and MRI. Sertraline reduced Lama4 and Ang2 expressions of TDEC, which play an important role in non-VEGF-mediated angiogenesis in tumors. The combination of a VEGF receptor inhibitor axitinib, and sertraline improved survival and reduced tumor growth in the 005 mouse model.

CONCLUSION

Collectively, our findings showed the diversity of tumor vascular endothelial cells across VEGF and non-VEGF pathways led to anti-angiogenic resistance. The combination of axitinib and sertraline can represent an effective anti-angiogenic therapy for glioblastoma with safe, low cost, and fast availability.

The identification of biomarkers for Alzheimer's disease using a systems biology approach based on lncRNA-circRNA-miRNA-mRNA ceRNA networks

In addition to being the most prevalent form of neurodegeneration among the elderly, AD is a devastating multifactorial disease. Currently, treatments address only its symptoms. Several clinical studies have shown that the disease begins to manifest decades before the first symptoms appear, indicating that studying early changes is crucial to improving early diagnosis and discovering novel treatments. Our study used bioinformatics and systems biology to identify biomarkers in AD that could be used for diagnosis and prognosis. The procedure was performed on data from the GEO database, and GO and KEGG enrichment analysis were performed. Then, we set up a network of interactions between proteins. Several miRNA prediction tools including miRDB, miRWalk, and TargetScan were used. The ceRNA network led to the identification of eight mRNAs, four circRNAs, seven miRNAs, and seven lncRNAs. Multiple mechanisms, including the cell cycle and DNA replication, have been linked to the promotion of AD development by the ceRNA network. By using the ceRNA network, it should be possible to extract prospective biomarkers and therapeutic targets for the treatment of AD. It is possible that the processes involved in DNA cell cycle and the replication of DNA contribute to the development of Alzheimer's disease.

Systematic Review of Cerebrospinal Fluid Biomarker Discovery in Neuro-Oncology: A Roadmap to Standardization and Clinical Application

Effective diagnosis, prognostication, and management of CNS malignancies traditionally involves invasive brain biopsies that pose significant risk to the patient. Sampling and molecular profiling of cerebrospinal fluid (CSF) is a safer, rapid, and noninvasive alternative that offers a snapshot of the intracranial milieu while overcoming the challenge of sampling error that plagues conventional brain biopsy. Although numerous biomarkers have been identified, translational challenges remain, and standardization of protocols is necessary. Here, we systematically reviewed 141 studies (Medline, SCOPUS, and Biosis databases; between January 2000 and September 29, 2022) that molecularly profiled CSF from adults with brain malignancies including glioma, brain metastasis, and primary and secondary CNS lymphomas. We provide an overview of promising CSF biomarkers, propose CSF reporting guidelines, and discuss the various considerations that go into biomarker discovery, including the influence of blood-brain barrier disruption, cell of origin, and site of CSF acquisition (eg, lumbar and ventricular). We also performed a meta-analysis of proteomic data sets, identifying biomarkers in CNS malignancies and establishing a resource for the research community.

Thrombin Cleavage of Osteopontin and the Host Anti-Tumor Immune Response

Osteopontin (OPN) is a multi-functional protein that is involved in various cellular processes such as cell adhesion, migration, and signaling. There is a single conserved thrombin cleavage site in OPN that, when cleaved, yields two fragments with different properties from full-length OPN. In cancer, OPN has tumor-promoting activity and plays a role in tumor growth and metastasis. High levels of OPN expression in cancer cells and tumor tissue are found in various types of cancer, including breast, lung, prostate, ovarian, colorectal, and pancreatic cancer, and are associated with poor prognosis and decreased survival rates. OPN promotes tumor progression and invasion by stimulating cell proliferation and angiogenesis and also facilitates the metastasis of cancer cells to other parts of the body by promoting cell adhesion and migration. Furthermore, OPN contributes to immune evasion by inhibiting the activity of immune cells. Thrombin cleavage of OPN initiates OPN's tumor-promoting activity, and thrombin cleavage fragments of OPN down-regulate the host immune anti-tumor response.

Effect of antibiotic-administration period on hepatic bile acid profile and expression of pharmacokinetic-related proteins in mouse liver, kidney, and brain capillaries

Antibiotic administration affects pharmacokinetics through changes in the intestinal microbiota, and bile acids are involved in this regulation. The purpose of the present study was to clarify the effect of different periods of antibiotic administration on the hepatic bile acid profile and expression of pharmacokinetic-related proteins in mouse liver, kidney, and brain capillaries. Vancomycin and polymyxin B were orally administered to mice for either 5- or 25-days. The hepatic bile acid profile of the 25-day treatment group was distinct. In the liver, the protein expression of cytochrome P450 (Cyp)3a11 showed the greatest reduction to 11.4% after the 5-day treatment and further reduced to 7.01% after the 25-day treatment. Similar reductions were observed for sulfotransferase 1d1, Cyp2b10, carboxylesterase 2e, UDP-glucuronosyltransferase (Ugt)1a5, and Ugt1a9. In the kidney and brain capillaries, no drug-metabolizing enzymes or drug transporters were changed with >1.5-fold or <0.66-fold statistical significance in either period. These results suggest that bile acids and metabolizing enzymes in the liver are affected in a period-dependent manner by antibiotic treatment, while the blood-brain barrier and kidneys are less affected. Drug-drug interactions of antibiotics via the intestinal microbiota should be considered by changing drug metabolism in the liver.

Assessment of Serum Hypoxia Biomarkers Pre- and Post-radiotherapy in Patients with Brain Tumors

Hypoxia is a prevalent hallmark of many malignant neoplasms. The aim was to assess the serum hypoxia biomarkers HIF-1α, VEGF, osteopontin, erythropoietin, caveolin-1, GLUT-1, and LDH pre- and post-radiotherapy in patients with brain tumors. The study was conducted on 120 subjects were divided into two groups: group I: 40 healthy volunteers as control group. Group II: 80 brain tumor patients were subdivided into glioblastoma subgroup: 40 glioblastoma patients, meningioma subgroup: 40 malignant meningioma patients. Two venous blood samples were collected from every patient prior to and following RT and one sample from controls. Biomarkers were assayed by ELISA. In glioblastoma subgroup, HIF-1α, VEGF, and LDH were significantly increased after RT. On the contrary, these biomarkers were significantly decreased after RT in malignant meningioma subgroup. Osteopontin was significantly increased after RT in both subgroups. Regarding erythropoietin, it was significantly decreased in both subgroups when compared to before RT. Caveolin-1 showed a significant increase in glioblastoma subgroup after RT comparing to before RT. GLUT-1 was significantly increased after RT in both subgroups comparing to before RT. Association of significant elevation of hypoxia biomarkers either pre- or post-RT with aggressive tumor such as glioblastoma indicates that, they are markers of malignancy and may have a role in tumor development and progression.

The complex interactions between the cellular and non-cellular components of the brain tumor microenvironmental landscape and their therapeutic implications

Glioblastoma (GBM), an aggressive high-grade glial tumor, is resistant to therapy and has a poor prognosis due to its universal recurrence rate. GBM cells interact with the non-cellular components in the tumor microenvironment (TME), facilitating their rapid growth, evolution, and invasion into the normal brain. Herein we discuss the complexity of the interactions between the cellular and non-cellular components of the TME and advances in the field as a whole. While the stroma of non-central nervous system (CNS) tissues is abundant in fibrillary collagens, laminins, and fibronectin, the normal brain extracellular matrix (ECM) predominantly includes proteoglycans, glycoproteins, and glycosaminoglycans, with fibrillary components typically found only in association with the vasculature. However, recent studies have found that in GBMs, the microenvironment evolves into a more complex array of components, with upregulated collagen gene expression and aligned fibrillary ECM networks. The interactions of glioma cells with the ECM and the degradation of matrix barriers are crucial for both single-cell and collective invasion into neighboring brain tissue. ECM-regulated mechanisms also contribute to immune exclusion, resulting in a major challenge to immunotherapy delivery and efficacy. Glioma cells chemically and physically control the function of their environment, co-opting complex signaling networks for their own benefit, resulting in radio- and chemo-resistance, tumor recurrence, and cancer progression. Targeting these interactions is an attractive strategy for overcoming therapy resistance, and we will discuss recent advances in preclinical studies, current clinical trials, and potential future clinical applications. In this review, we also provide a comprehensive discussion of the complexities of the interconnected cellular and non-cellular components of the microenvironmental landscape of brain tumors to guide the development of safe and effective therapeutic strategies against brain cancer.

Advances in sample preparation for membrane proteome quantification

Membrane proteins mediate various biological processes. Most drugs commercially available target proteins on the cell surface. Therefore, proteomics of plasma membrane proteins provides useful information for drug discovery. However, membrane proteins are one of the most difficult biological groups to quantify by proteomics because of their hydrophobicity and low protein content. To obtain unbiased quantitative membrane proteomics data, specific strategies should be followed during sample preparation. This review explores the most recent advances in sample preparation for the quantitative analysis of the membrane proteome, including enrichment by subcellular fractionation and trypsin digestion.

Effect of Insulin Receptor-Knockdown on the Expression Levels of Blood-Brain Barrier Functional Proteins in Human Brain Microvascular Endothelial Cells

PURPOSE

The insulin receptor (INSR) mediates insulin signaling to modulate cellular functions. Although INSR is expressed at the blood-brain barrier (BBB), its role in the modulation of BBB function is poorly understood. Therefore, in this study, we aimed to analyze the effect of INSR knockdown on the expression levels of functional proteins at the BBB.

METHODS

We established the INSR-knockdown cell line (shINSR) using human cerebral microvascular endothelial cells (hCMEC/D3). The cellular proteome was analyzed using quantitative proteomics.

RESULTS

INSR mRNA and protein expressions were decreased in shINSR cells. The suppression of INSR-mediated signaling in shINSR cells was evaluated. The proteins involved in glycolysis and glycogenolysis were suppressed in shINSR cells. As amyloid-β peptide-related proteins, the expressions of presenilin-1 was increased, and those of the insulin-degrading enzyme and neprilysin were decreased. The expressions of BBB transporters, including the ABCB1/MDR1, ABCG2/BCRP, and SLCO2A1/OATP2A1 were significantly decreased by more than 50% in shINSR cells. The efflux activity of ABCB1/MDR1 was also suppressed. The expressions of the low-density lipoprotein receptor-related protein 1 were significantly increased, and those of the transferrin receptor were significantly decreased in shINSR cells. The expression of claudin-5 was also suppressed in shINSR cells.

CONCLUSIONS

The present study suggests that INSR-mediated signaling is involved in the regulation of functional protein expression at the BBB and contributes to the maintenance of BBB function. Changes in the expressions of amyloid-β peptide-related proteins may contribute to the development of cerebral amyloid angiopathy via the suppression of INSR-mediated signaling.