Proteoglycans as Therapeutic Targets in Brain Cancer

Network pharmacology-based investigation of the effects of Shenqi Fuzheng injection on glioma proliferation and migration via the SRC/PI3K/AKT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

In the clinic, Shenqi Fuzheng Injection (SFI) is used as an adjuvant for cancer chemotherapy. However, the molecular mechanism is unclear.

AIM OF THE STUDY

We screened potential targets of SFI action on gliomas by network pharmacology and performed experiments to validate possible molecular mechanisms against gliomas.

MATERIALS AND METHODS

We consulted relevant reports on the SFI and glioma incidence from PubMed and Web of Science and focused on the mechanism through which the SFI inhibits glioma. According to the literature, two primary SFI components-Codonopsis pilosula (Franch.) Nannf. and Astragalus membranaceus (Fisch.) Bunge-have been found. All plant names have been sourced from "The Plant List" (www.theplantlist.org). The cell lines U87, T98G and GL261 were used in this study. The inhibitory effects of SFI on glioma cells U87 and T98G were detected by CCK-8 assay, EdU, plate cloning assay, scratch assay, Transwell assay, immunofluorescence, flow cytometry and Western blot. A subcutaneous tumor model of C57BL/6 mice was constructed using GL261 cells, and the SFI was evaluated by HE staining and immunohistochemistry. The targets of glioma and the SFI were screened using network pharmacology.

RESULTS

A total of 110 targets were enriched, and a total of 26 major active components in the SFI were investigated. There were a total of 3,343 targets for gliomas, of which 79 targets were shared between the SFI and glioma tissues. SFI successfully prevented proliferation and caused cellular S-phase blockage in U87 and T98G cells, thus decreasing their growth. Furthermore, SFI suppressed cell migration by downregulating EMT marker expression. According to the results of the in vivo tests, the SFI dramatically decreased the development of tumors in a transplanted tumour model. Network pharmacological studies revealed that the SRC/PI3K/AKT signaling pathway may be the pathway through which SFI exerts its anti-glioma effects.

CONCLUSIONS

The findings revealed that the SRC/PI3K/AKT signaling pathway may be involved in the mechanism through which SFI inhibits the proliferation and migration of glioma cells.

The Expression of Serglycin Is Required for Active Transforming Growth Factor β Receptor I Tumorigenic Signaling in Glioblastoma Cells and Paracrine Activation of Stromal Fibroblasts via CXCR-2

Serglycin (SRGN) is a pro-tumorigenic proteoglycan expressed and secreted by various aggressive tumors including glioblastoma (GBM). In our study, we investigated the interplay and biological outcomes of SRGN with TGFβRI, CXCR-2 and inflammatory mediators in GBM cells and fibroblasts. SRGN overexpression is associated with poor survival in GBM patients. High SRGN levels also exhibit a positive correlation with increased levels of various inflammatory mediators including members of TGFβ signaling pathway, cytokines and receptors including CXCR-2 and proteolytic enzymes in GBM patients. SRGN-suppressed GBM cells show decreased expressions of TGFβRI associated with lower responsiveness to the manipulation of TGFβ/TGFβRI pathway and the regulation of pro-tumorigenic properties. Active TGFβRI signaling in control GBM cells promotes their proliferation, invasion, proteolytic and inflammatory potential. Fibroblasts cultured with culture media derived by control SRGN-expressing GBM cells exhibit increased proliferation, migration and overexpression of cytokines and proteolytic enzymes including CXCL-1, IL-8, IL-6, IL-1β, CCL-20, CCL-2, and MMP-9. Culture media derived by SRGN-suppressed GBM cells fail to induce the above properties to fibroblasts. Importantly, the activation of fibroblasts by GBM cells not only relies on the expression of SRGN in GBM cells but also on active CXCR-2 signaling both in GBM cells and fibroblasts.

CHST12: a potential prognostic biomarker related to the immunotherapy response in pancreatic adenocarcinoma

Background

Pancreatic adenocarcinoma (PAAD) is characterized by lower immunogenicity with a poor response rate to immune checkpoint inhibitors (ICIs) and exhibits the poorest prognosis of all solid tumors, which results in the highest tumor-related mortality among malignancies. However, the underlying mechanisms are poorly understood. In addition, diverse carbohydrate sulfotransferases (CHSTs), which are involved in the sulfation process of these structures, play an important role in the metastatic spread of tumor cells. Aberrant glycosylation is beginning to emerge as an influencing factor in tumor immunity and immunotherapy. Therefore, it might serve as a biomarker of the immunotherapeutic response in tumors. The purpose of the study was to evaluate the role of CHST12 in PAAD prognosis and its relevance to the immunotherapeutic response.

Methods

A comprehensive investigation of the interactions between CHST12 expression and the immune microenvironment as well as the clinical significance of CHST12 in PAAD was conducted. Data derived from the Cancer Genome Atlas (TCGA) database were analyzed using univariate and multivariate approaches, the Tumor Immune Estimation Resource (TIMER), and Tumor Immune Dysfunction and Exclusion (TIDE) algorithms. Publicly available datasets were analyzed in this study. These data can be found on websites such as http://www.xiantao.love and https://www.proteinatlas.org. An assessment of the predictive value of CHST12 for PAAD prognosis was conducted using univariate and multivariate Cox regression analysis, Kaplan-Meier analysis, and nomograms. The TIMER algorithm calculates the proportions of six types of immune cells. The TIDE algorithm was used to indicate the characteristics of tumors that respond to ICI therapy.

Results

The mRNA and protein levels of CHST12 showed the opposite trend. CHST12 mRNA expression was significantly upregulated in PAAD. According to Cox regression analysis, CHST12 RNA expression acts as a protective factor for overall survival [hazard ratio (HR), 0.617, P < 0.04]. Functional annotation indicated that CHST12-associated differentially expressed genes (DEGs) were related to the signaling activity of receptor tyrosine kinases and the regulation of ubiquitin-protein transferase. These are usually involved in tumor development and may be related to the treatment responses of immune checkpoint inhibitors (ICIs). There was significantly higher CHST12 mRNA expression in PAAD samples than in non-malignant samples.

Conclusions

In PAAD, elevated CHST12 mRNA expression might regulate immune cell infiltration into the tumor microenvironment (TME) and may predict clinical outcomes.

Glucocorticoid Effects on Proteoglycans and Glycosaminoglycans

Glucocorticoids are steroid hormones that play diverse roles in numerous normal and pathological processes. They are actively used to treat a wide variety of diseases, including neurodegenerative and inflammatory diseases, cancers, and COVID-19, among others. However, the long-term use of glucocorticoids is associated with numerous side effects. Molecular mechanisms of these negative side effects are not completely understood. Recently, arguments have been made that one such mechanisms may be related to the influence of glucocorticoids on O-glycosylated components of the cell surface and extracellular matrix, in particular on proteoglycans and glycosaminoglycans. The potential toxic effects of glucocorticoids on these glycosylated macromolecules are particularly meaningful for brain physiology because proteoglycans/glycosaminoglycans are the main extracellular components of brain tissue. Here, we aim to review the known effects of glucocorticoids on proteoglycan expression and glycosaminoglycan content in different tissues, with a specific focus on the brain.

Identification of novel proteins for lacunar stroke by integrating genome-wide association data and human brain proteomes

BACKGROUND

Previous genome-wide association studies (GWAS) have identified numerous risk genes for lacunar stroke, but it is challenging to decipher how they confer risk for the disease. We employed an integrative analytical pipeline to efficiently transform genetic associations to identify novel proteins for lacunar stroke.

METHODS

We systematically integrated lacunar stroke genome-wide association study (GWAS) (N=7338) with human brain proteomes (N=376) to perform proteome-wide association studies (PWAS), Mendelian randomization (MR), and Bayesian colocalization. We also used an independent human brain proteomic dataset (N=152) to annotate the new genes.

RESULTS

We found that the protein abundance of seven genes (ICA1L, CAND2, ALDH2, MADD, MRVI1, CSPG4, and PTPN11) in the brain was associated with lacunar stroke. These seven genes were mainly expressed on the surface of glutamatergic neurons, GABAergic neurons, and astrocytes. Three genes (ICA1L, CAND2, ALDH2) were causal in lacunar stroke (P < 0.05/proteins identified for PWAS; posterior probability of hypothesis 4 ≥ 75 % for Bayesian colocalization), and they were linked with lacunar stroke in confirmatory PWAS and independent MR. We also found that ICA1L is related to lacunar stroke at the brain transcriptome level.

CONCLUSIONS

Our present proteomic findings have identified ICA1L, CAND2, and ALDH2 as compelling genes that may give key hints for future functional research and possible therapeutic targets for lacunar stroke.

Novel Insight Into Glycosaminoglycan Biosynthesis Based on Gene Expression Profiles

Glycosaminoglycans (GAGs) including chondroitin sulfate, dermatan sulfate, heparan sulfate, and keratan sulfate, except for hyaluronan that is a free polysaccharide, are covalently attached to core proteins to form proteoglycans. More than 50 gene products are involved in the biosynthesis of GAGs. We recently developed a comprehensive glycosylation mapping tool, GlycoMaple, for visualization and estimation of glycan structures based on gene expression profiles. Using this tool, the expression levels of GAG biosynthetic genes were analyzed in various human tissues as well as tumor tissues. In brain and pancreatic tumors, the pathways for biosynthesis of chondroitin and dermatan sulfate were predicted to be upregulated. In breast cancerous tissues, the pathways for biosynthesis of chondroitin and dermatan sulfate were predicted to be up- and down-regulated, respectively, which are consistent with biochemical findings published in the literature. In addition, the expression levels of the chondroitin sulfate-proteoglycan versican and the dermatan sulfate-proteoglycan decorin were up- and down-regulated, respectively. These findings may provide new insight into GAG profiles in various human diseases including cancerous tumors as well as neurodegenerative disease using GlycoMaple analysis.

The IL13α 2R paves the way for anti-glioma nanotherapy

Glioblastoma (GBM) is one of the most aggressive (grade IV) gliomas characterized by a high rate of recurrence, resistance to therapy and a grim survival prognosis. The long-awaited improvement in GBM patients' survival rates essentially depends on advances in the development of new therapeutic approaches. Recent preclinical studies show that nanoscale materials could greatly contribute to the improvement of diagnosis and management of brain cancers. In the current review, we will discuss how specific features of glioma pathobiology can be employed for designing efficient targeting approaches. Moreover, we will summarize the main evidence for the potential of the IL-13R alpha 2 receptor (IL13α2R) targeting in GBM early diagnosis and experimental therapy.

Knockdown of carbohydrate sulfotransferase 12 decreases the proliferation and mobility of glioblastoma cells via the WNT/β-catenin pathway

Glioblastoma (GBM) is a common malignant tumor of the brain. Members of the carbohydrate sulfotransferase (CHST) family are deregulated in various cancer types. However, limited data are available on the role of the members of the CHST family in the development of GBM. The present study aimed to identify the role of significant members of the CHST family in GBM and explore the effects and molecular mechanisms of these significant members on GBM cell proliferation and mobility. In the current study, we demonstrated that CHST12 is the only member of CHST family that is upregulated in GBM tissues and associated with a lower survival rate according to the data obtained from The Cancer Genome Atlas. Similarly, the expression of CHST12 increased in GBM tissues than in adjacent tissues and had an important diagnostic value in distinguishing tumor tissues from adjacent tissues. The high expression of CHST12 indicated a lower overall survival rate, was negatively associated with the Karnofsky Performance Scale score, was positively associated with the KI67 expression rate, and was an independent risk factor for GBM. Knockdown of CHST12 significantly decreased GBM cell proliferation and mobility and inhibited the Wnt/β-catenin pathway. Restoration of β-catenin expression in GBM cells reversed the inhibitory effects of CHST12 knockdown on GBM cell proliferation and mobility. In conclusion, the present study demonstrated that CHST12 may be a novel biomarker for GBM; it regulates GBM cell proliferation and mobility via the WNT/β-catenin pathway.

Chemotherapy-Induced Degradation of Glycosylated Components of the Brain Extracellular Matrix Promotes Glioblastoma Relapse Development in an Animal Model

Adjuvant chemotherapy with temozolomide (TMZ) is an intrinsic part of glioblastoma multiforme (GBM) therapy targeted to eliminate residual GBM cells. Despite the intensive treatment, a GBM relapse develops in the majority of cases resulting in poor outcome of the disease. Here, we investigated off-target negative effects of the systemic chemotherapy on glycosylated components of the brain extracellular matrix (ECM) and their functional significance. Using an elaborated GBM relapse animal model, we demonstrated that healthy brain tissue resists GBM cell proliferation and invasion, thereby restricting tumor development. TMZ-induced [especially in combination with dexamethasone (DXM)] changes in composition and content of brain ECM proteoglycans (PGs) resulted in the accelerated adhesion, proliferation, and invasion of GBM cells into brain organotypic slices ex vivo and more active growth and invasion of experimental xenograft GBM tumors in SCID mouse brain in vivo. These changes occurred both at core proteins and polysaccharide chain levels, and degradation of chondroitin sulfate (CS) was identified as a key event responsible for the observed functional effects. Collectively, our findings demonstrate that chemotherapy-induced changes in glycosylated components of brain ECM can impact the fate of residual GBM cells and GBM relapse development. ECM-targeted supportive therapy might be a useful strategy to mitigate the negative off-target effects of the adjuvant GBM treatment and increase the relapse-free survival of GBM patients.