Overexpression of Biglycan is Associated with Resistance to Rapamycin in Human WERI-Rb-1 Retinoblastoma Cells by Inducing the Activation of the Phosphatidylinositol 3-Kinases (PI3K)/Akt/Nuclear Factor kappa B (NF-κB) Signaling Pathway

The Proteoglycans Biglycan and Decorin Protect Cardiac Cells against Irradiation-Induced Cell Death by Inhibiting Apoptosis

Radiation-induced heart disease (RIHD), a common side effect of chest irradiation, is a primary cause of mortality among patients surviving thoracic cancer. Thus, the development of novel, clinically applicable cardioprotective agents which can alleviate the harmful effects of irradiation on the heart is of great importance in the field of experimental oncocardiology. Biglycan and decorin are structurally related small leucine-rich proteoglycans which have been reported to exert cardioprotective properties in certain cardiovascular pathologies. Therefore, in the present study we aimed to examine if biglycan or decorin can reduce radiation-induced damage of cardiomyocytes. A single dose of 10 Gray irradiation was applied to induce radiation-induced cell damage in H9c2 cardiomyoblasts, followed by treatment with either biglycan or decorin at various concentrations. Measurement of cell viability revealed that both proteoglycans improved the survival of cardiac cells post-irradiation. The cardiocytoprotective effect of both biglycan and decorin involved the alleviation of radiation-induced proapoptotic mechanisms by retaining the progression of apoptotic membrane blebbing and lowering the number of apoptotic cell nuclei and DNA double-strand breaks. Our findings provide evidence that these natural proteoglycans may exert protection against radiation-induced damage of cardiac cells.

The Landscape of Small Leucine-Rich Proteoglycan Impact on Cancer Pathogenesis with a Focus on Biglycan and Lumican

Cancer development is a multifactorial procedure that involves changes in the cell microenvironment and specific modulations in cell functions. A tumor microenvironment contains tumor cells, non-malignant cells, blood vessels, cells of the immune system, stromal cells, and the extracellular matrix (ECM). The small leucine-rich proteoglycans (SLRPs) are a family of nineteen proteoglycans, which are ubiquitously expressed among mammalian tissues and especially abundant in the ECM. SLRPs are divided into five canonical classes (classes I-III, containing fourteen members) and non-canonical classes (classes IV-V, including five members) based on their amino-acid structural sequence, chromosomal organization, and functional properties. Variations in both the protein core structure and glycosylation status lead to SLRP-specific interactions with cell membrane receptors, cytokines, growth factors, and structural ECM molecules. SLRPs have been implicated in the regulation of cancer growth, motility, and invasion, as well as in cancer-associated inflammation and autophagy, highlighting their crucial role in the processes of carcinogenesis. Except for the class I SLRP decorin, to which an anti-tumorigenic role has been attributed, other SLPRs' roles have not been fully clarified. This review will focus on the functions of the class I and II SLRP members biglycan and lumican, which are correlated to various aspects of cancer development.

Development of a Cancer-Associated Fibroblast-Related Prognostic Model in Breast Cancer via Bulk and Single-Cell RNA Sequencing

Background

The most numerous cells in the tumor microenvironment, cancer-associated fibroblasts (CAFs) play a crucial role in cancer development. Our objective was to develop a cancer-associated fibroblast breast cancer predictive model.

Methods

We acquire breast cancer (BC) scRNA-seq data from Gene Expression Omnibus (GEO), and "Seurat" was used for data processing, including quality control, filtering, principal component analysis, and t-SNE. Afterward, "singleR" software was used to annotate cells. Seurat's "FindAllMarkers" program is used to locate particular CAF markers. clusterProfiler was used to analyze Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. The Cancer Genome Atlas (TCGA) database was utilized to provide univariate Cox regression, least absolute shrinkage operator (LASSO) analysis using bulk RNA-seq data. For model development, multivariate Cox regression studies are used. Utilizing pRRophetic and Tumor Immune Dysfunction and Exclusion (TIDE) algorithms, chemosensitivity and immunotherapy response were predicted. The "rms" software was used to facilitate and simplify modeling.

Results

Integrating the scRNA-seq (GSE176078) dataset yielded 28 cell clusters. In addition, well-known cell types helped identify 12 cell types. We found 193 marker genes that are elevated in CAFs. In addition, a five-gene predictive model associated to CAF was created in the training set. In the training set, the validation set, and the external validation set, greater risk scores were associated with a worse prognosis. And individuals with a higher risk score were more susceptible to immunotherapy and conventional chemotherapy medicines.

Conclusion

In conclusion, we establish a strong prognostic model comprised of 5 genes related with CAF that might serve as a potent prognostic indicator and aid clinicians in making more rational medication choices.

Expression and prognostic analysis of BGN in head and neck squamous cell carcinoma

OBJECTIVE

BGN belongs to class of small leucine rich proteoglycans, which is high expression in plenty of human cancers. However, the detailed role of BGN remains unclear in Head and neck squamous cell carcinoma (HNSC).

MATERIALS AND METHODS

In this study, we assessed the transcriptional expression, protein expression, prognosis, co-expressed genes, functional enrichment, and hub genes in HNSC patients based on the data published in the following databases: ONCOMINE, GEPIA, GEO, LinkedOmics, and HPA databases. Data from the TCGA database was used to analyze the correlations between BGN expression and different clinicopathological features, as well as prognostic analysis.

RESULTS

We found that the expression of BGN is higher in patients with HNSC than in control tissues. Pathologically, high BGN expression was significantly correlated with T3 and T4 stage. Besides, high expression of BGN is a poor prognostic factor for overall surviva, not disease free survival. The co-expression genes associated with BGN expression exhibited enriched in various function and pathway, such as extracellular matrix, mitochondrion, PI3K-Akt signaling pathway. A total of 10 hub genes were identified from the co-expressed genes, within which five genes, including FSTL1, LAMB1, SDC2, VCAN, and IGFBP7, were significantly increased in patient's with HNSC. BGN exhibited weak correlations with tumor-infiltrating CD4+ T, macrophages cell, and dendritic cells. Futhermore, many markers of infiltrating immune cells, such as Treg, showed different BGN-related immune infiltration patterns. BGN expression showed strong correlations with diverse immune marker sets in COAD and STAD.

CONCLUSIONS

Our results demonstrated that BGN is high expression in HNSC and is a poor prognostic factor for clinical outcome in patients with HNSC. It could serve as a potential prognostic biomarker for patients survival in HNSC.

Identification of Hub Biomarkers and Immune-Related Pathways Participating in the Progression of Antineutrophil Cytoplasmic Antibody-Associated Glomerulonephritis

Background

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a systemic autoimmune disease that generally induces the progression of rapidly progressive glomerulonephritis (GN). The purpose of this study was to identify key biomarkers and immune-related pathways involved in the progression of ANCA-associated GN (ANCA-GN) and their relationship with immune cell infiltration.

Methods

Gene microarray data were downloaded from the Gene Expression Omnibus (GEO). Hub markers for ANCA-GN were mined based on differential expression analysis, weighted gene co-expression network analysis (WGCNA) and lasso regression, followed by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Set Enrichment Analysis (GSEA) of the differential genes. The infiltration levels of 28 immune cells in the expression profile and their relationship to hub gene markers were analysed using single-sample GSEA (ssGSEA). In addition, the accuracy of the hub markers in diagnosing ANCA-GN was subsequently evaluated using the receiver operating characteristic curve (ROC).

Results

A total of 651 differential genes were screened. Twelve co-expression modules were obtained via WGCNA; of which, one hub module (black module) had the highest correlation with ANCA-GN. A total of 66 intersecting genes were acquired by combining differential genes. Five hub genes were subsequently obtained by lasso analysis as potential biomarkers for ANCA-GN. The immune infiltration results revealed the most significant relationship among monocytes, CD4⁺ T cells and CD8⁺ T cells. ROC curve analysis demonstrated a prime diagnostic value of the five hub genes. According to the functional enrichment analysis of the differential genes, hub genes were mainly enhanced in immune- and inflammation-related pathways.

Conclusion

B cells and monocytes were closely associated with the pathogenesis of ANCA-GN. Hub genes (CYP3A5, SLC12A3, BGN, TAPBP and TMEM184B) may be involved in the progression of ANCA-GN through immune-related signal pathways.

Biglycan Promotes Cancer Stem Cell Properties, NFκB Signaling and Metastatic Potential in Breast Cancer Cells

Simple Summary

Breast cancer stem cells (BCSCs) are a small sub-population of cells within tumors with high metastatic potential. We identified biglycan (BGN) as a prospective molecular target in BCSCs that regulates the aggressive phenotypes of these cells. These findings establish a foundation for the development of therapeutics against BGN to eliminate BCSCs and prevent metastatic breast cancer.

Abstract

It is a major challenge to treat metastasis due to the presence of heterogenous BCSCs. Therefore, it is important to identify new molecular targets and their underlying molecular mechanisms in various BCSCs to improve treatment of breast cancer metastasis. Here, we performed RNA sequencing on two distinct co-existing BCSC populations, ALDH⁺ and CD29^hi CD61⁺ from PyMT mammary tumor cells and detected upregulation of biglycan (BGN) in these BCSCs. Genetic depletion of BGN reduced BCSC proportions and tumorsphere formation. Furthermore, BCSC associated aggressive traits such as migration and invasion were significantly reduced by depletion of BGN. Glycolytic and mitochondrial metabolic assays also revealed that BCSCs exhibited decreased metabolism upon loss of BGN. BCSCs showed decreased activation of the NFκB transcription factor, p65, and phospho-IκB levels upon BGN ablation, indicating regulation of NFκB pathway by BGN. To further support our data, we also characterized CD24⁻/CD44⁺ BCSCs from human luminal MCF-7 breast cancer cells. These CD24⁻/CD44⁺ BCSCs similarly exhibited reduced tumorigenic phenotypes, metabolism and attenuation of NFκB pathway after knockdown of BGN. Finally, loss of BGN in ALDH⁺ and CD29^hi CD61⁺ BCSCs showed decreased metastatic potential, suggesting BGN serves as an important therapeutic target in BCSCs for treating metastasis of breast cancer.

Landscape of cancer-associated fibroblasts identifies the secreted biglycan as a protumor and immunosuppressive factor in triple-negative breast cancer

Cancer-associated fibroblasts (CAFs) are essential for tumor microenvironment remodeling and correlate with tumor progression. However, interactions between CAFs and tumor cells and immune cells in triple-negative breast cancer (TNBC) are still poorly explored. Here, we investigate the role of CAFs in TNBC and potential novel mediators of their functions. The clustering of classic markers was applied to estimate the relative abundance of CAFs in TNBC cohorts. Primary fibroblasts were isolated from normal and tumor samples. The RNA and culture medium of fibroblasts were subjected to RNA sequencing and mass spectrometry to explore the upregulated signatures in CAFs. Microdissection and single-cell RNA sequencing datasets were used to examine the expression profiles. CAFs were associated with hallmark signalings and immune components in TNBC. Clustering based on CAF markers in the literature revealed different CAF infiltration groups in TNBC: low, medium and high. Most of the cancer hallmark signaling pathways were enriched in the high CAF infiltration group. Furthermore, RNA sequencing and mass spectrometry identified biglycan (BGN), a soluble secreted protein, as upregulated in CAFs compared to normal cancer-adjacent fibroblasts (NAFs). The expression of biglycan was negatively correlated with CD8 + T cells. Biglycan indicated poor prognostic outcomes and might be correlated with the immunosuppressive tumor microenvironment (TME). In conclusion, CAFs play an essential role in tumor progression and the TME. We identified an extracellular protein, biglycan, as a prognostic marker and potential therapeutic target in TNBC.

Biglycan: an emerging small leucine-rich proteoglycan (SLRP) marker and its clinicopathological significance

Extracellular matrix (ECM) plays an important role in the structural organization of tissue and delivery of external cues to the cell. Biglycan, a class I small leucine-rich proteoglycans (SLRP), is a key component of the ECM that participates in scaffolding the collagen fibrils and mediates cell signaling. Dysregulation of biglycan expression can result in wide range of clinical conditions such as metabolic disorder, inflammatory disorder, musculoskeletal defects and malignancies. In this review, we aim to update our current understanding regarding the link between altered expression of biglycan and different clinicopathological states. Biglycan interacts with toll like receptors (TLR)-2 and TLR-4 on the immune cells which initiates inflammation and aggravates inflammatory disorders. ECM unbound soluble biglycan acts as a DAMP (danger associated molecular pattern) resulting in sterile inflammation. Dysregulation of biglycan expression is also observed in inflammatory metabolic conditions such as atherosclerosis and obesity. In cancer, high-biglycan expression facilitates tumor growth, invasion and metastasis which is associated with poor clinical outcome. As a pivotal structural component of the ECM, biglycan strengthens the musculoskeletal system and its absence is associated with musculoskeletal defects. Thus, SLRP biglycan is a potential marker which is significantly altered in different clinicopathological states.

PODNL1 promotes cell proliferation and migration in glioma via regulating Akt/mTOR pathway

Background and Aims: Emerging studies have determined that the small leucine-rich proteoglycan (SLRP) family can aggravate tumor progression. However, the biological function of podocan-like protein 1 (PODNL1), a novel member of the SLRP family, has not been investigated. Therefore, our study focused on the function and regulatory mechanism of PODNL1 in glioma.

Methods: Both the Gene Expression Profiling Interactive Analysis (GEPIA) and the Chinese Glioma Genome Atlas (CGGA) database were used to analyze the expression level and survival risk of PODNL1 in glioma. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were applied to detect the mRNA and protein expression, respectively. Celltiter-Glo and colony formation assays were used to evaluate cell proliferation. Migration capacity was measured by Transwell and wound healing assays. Flow cytometry was utilized to assess the apoptotic rate.

Results: The expression of PODNL1 predicted the poor prognosis in glioma patients. Silencing of PODNL1 inhibited cell proliferation, migration, and induced epithelial-like phenotype. In addition, knockdown of PODNL1 also induced cell apoptosis. Moreover, the cell growth and migration inhibited by PODNL1 knockdown could be partially rescued with Akt activator. Conversely, PODNL1 overexpression promoted cell growth and migration, which were suppressed by Akt inhibitor.

Conclusions: PODNL1, a promising predictive indicator of poor prognosis, resulted in greater proliferation, migration and epithelial-mesenchymal transition (EMT) process. Moreover, PODNL1 promoted aggressive glioma behavior by activating Akt/mTOR pathway, providing a novel therapeutic target for glioma.

Triptolide inhibits PDGF-induced proliferation of ASMCs through G0/G1 cell cycle arrest and suppression of the AKT/NF-κB/cyclinD1 signaling pathway

Abnormal proliferation of airway smooth muscle cells (ASMCs) is a hallmark of airway remodeling. Platelet-derived growth factor (PDGF) is known to be a major stimulus inducing the proliferation of ASMCs. It has been reported that triptolide demonstrates protective effects against airway remodeling. In this study, we investigated the antiproliferative effects of triptolide on PDGF-induced ASMCs and its underlying mechanisms. Cell proliferation was determined using the Cell Counting Kit-8 (CCK-8) assay. Flow cytometry was used to study the influence of triptolide on cell cycle and apoptosis. Quantitative real-time PCR and Western blot analysis were employed to detect the expression of proliferating cell nuclear antigen (PCNA), cyclinD1 and cyclin dependent kinase 4 (CDK4). Proteins involved in the protein kinase B (AKT) and nuclear factor kappa B (NF-κB) signaling pathways were evaluated using Western blot analysis. Triptolide could significantly inhibit cell proliferation, induce cell cycle arrest in the G0/G1 phase, and reduce the expression of PCNA, cyclinD1, and CDK4 in PDGF-treated ASMCs. Levels of phosphorylated AKT, p65 and NF-κB inhibitor α (IκBα) stimulated by the presence of PDGF were markedly suppressed after triptolide treatment. Moreover, triptolide cotreatment with the phosphatidylinositol 3 kinase (PI3k) inhibitor, 2-(4-morpholinyl)-8-phenylchromone (LY294002), could further suppress the proliferation, NF-κB activation and cyclinD1 expression. Similar results were observed after triptolide cotreatment with the NF-κB inhibitor, ammonium pyrrolidinedithiocarbamate (PDTC). Our results suggest that triptolide could inhibit the PDGF-induced proliferation of ASMCs through G0/G1 cell cycle arrest and suppression of the AKT/NF-κB/cyclinD1 signaling pathway.