Biglycan, tumor endothelial cell secreting proteoglycan, as possible biomarker for lung cancer

Biglycan promotes proliferation and metastasis of ovarian cancer

OBJECTIVE

Ovarian cancer (OC) is a significant threat to the health of women. Biglycan (BGN) plays a crucial role in the oncogenesis and progression of various human cancers. The aim of this study was to clarify the role of BGN in OC.

METHODS

Immunohistochemical analysis was performed to detect BGN levels in the OC tissues of 68 patients who underwent cytoreductive surgery. Normal ovarian tissues were collected from 21 patients with benign gynecological tumors who underwent oophorectomy. Western blot analysis was conducted to detect BGN levels in human OC and normal ovarian cells. The functions of BGN in OC cells were assessed with the Cell Counting Kit-8, wound healing, and transwell migration assays following upregulation or downregulation of BGN in vitro.

RESULTS

BGN expression was elevated in OC tissues as compared to normal tissues. The basal level of BGN was also higher in OC cells than in normal cells. Knockdown of BGN reduced the proportion of surviving OC cells, increased wound healing, and decreased cell migration, while overexpression produced the opposite effects.

CONCLUSIONS

These findings suggest that high BGN expression enhances proliferation and migration of OC cells, indicating that BGN is a potential target for treatment of OC.

PDK1 promotes epithelial ovarian cancer progression by upregulating BGN

Pyruvate dehydrogenase kinase 1 (PDK1) is a new therapeutic target that is dysregulated in multiple tumors. This study aims to explore the potential role and regulatory mechanism of PDK1 in epithelial ovarian cancer (EOC). We detect PDK1 expression in EOC tissues and cells using qRT-PCR and western blot analysis, and the effects of PDK1 on EOC cell malignant behaviors are explored. RNA sequencing analyses are performed to explore the differentially expressed genes in PDK1-silenced EOC cells. Furthermore, tumor-bearing mouse models are established to assess the impacts of PDK1 and BGN on EOC tumor growth and metastasis in vivo. The results show that PDK1 is upregulated in EOC tissues and cell lines. Biglycan (BGN) is downregulated in PDK1-silenced EOC cells, and its expression is positively correlated with PDK1 levels in EOC tissues. PDK1 depletion inhibits EOC cell proliferation, migration and invasion. Mechanistically, PDK1 and BGN are colocalized in the cytoplasm of EOC cells and interact with each other. PDK1 positively regulates BGN expression by enhancing BGN mRNA stability. BGN overexpression partially reverses the anti-tumor effects of PDK1 depletion on EOC cell malignant behaviors. PDK1 has also been revealed to upregulate BGN to activate the NF-κB oncogenic pathway in EOC cells. Additionally, PDK1 accelerates tumor growth and metastasis by modulating BGN expression. In conclusion, PDK1 functions as an oncogene, facilitating EOC progression by upregulating BGN and activating the NF-κB pathway. These findings may provide valuable biomarkers for the diagnosis and treatment of EOC.

Soluble Proteoglycans and Proteoglycan Fragments as Biomarkers of Pathological Extracellular Matrix Remodeling

Proteoglycans and their proteolytic fragments diffuse into biological fluids such as plasma, serum, urine, or synovial fluid, where they can be detected by antibodies or mass-spectrometry. Neopeptides generated by the proteolysis of proteoglycans are recognized by specific neoepitope antibodies and can act as a proxy for the activity of certain proteases. Proteoglycan and proteoglycan fragments can be potentially used as prognostic, diagnostic, or theragnostic biomarkers for several diseases characterized by dysregulated extracellular matrix remodeling such as osteoarthritis, rheumatoid arthritis, atherosclerosis, thoracic aortic aneurysms, central nervous system disorders, viral infections, and cancer. Here, we review the main mechanisms accounting for the presence of soluble proteoglycans and their fragments in biological fluids, their potential application as diagnostic, prognostic, or theragnostic biomarkers, and highlight challenges and opportunities ahead of their clinical translation.

A biological guide to glycosaminoglycans: current perspectives and pending questions

Mammalian glycosaminoglycans (GAGs), except hyaluronan (HA), are sulfated polysaccharides that are covalently attached to core proteins to form proteoglycans (PGs). This article summarizes key biological findings for the most widespread GAGs, namely HA, chondroitin sulfate/dermatan sulfate (CS/DS), keratan sulfate (KS), and heparan sulfate (HS). It focuses on the major processes that remain to be deciphered to get a comprehensive view of the mechanisms mediating GAG biological functions. They include the regulation of GAG biosynthesis and postsynthetic modifications in heparin (HP) and HS, the composition, heterogeneity, and function of the tetrasaccharide linkage region and its role in disease, the functional characterization of the new PGs recently identified by glycoproteomics, the selectivity of interactions mediated by GAG chains, the display of GAG chains and PGs at the cell surface and their impact on the availability and activity of soluble ligands, and on their move through the glycocalyx layer to reach their receptors, the human GAG profile in health and disease, the roles of GAGs and particular PGs (syndecans, decorin, and biglycan) involved in cancer, inflammation, and fibrosis, the possible use of GAGs and PGs as disease biomarkers, and the design of inhibitors targeting GAG biosynthetic enzymes and GAG-protein interactions to develop novel therapeutic approaches.

The Diagnostic and Prognostic Value of the Immune Checkpoint BGN in Thymoma

Thymoma is frequently correlated with various autoimmune diseases. However, unequivocal therapeutic targets for thymoma remain undefined, and the role of immune checkpoints in the development of thymoma-related autoimmune illnesses is unclear. We examined 39 thymoma samples and 44 normal control samples from the GEO database. Following batch correction, we identified 224 Differentially Expressed Genes (DEGs) using the Limma package. We employed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses to enrich for functional pathways of DEGs. We utilized a Protein-Protein Interaction (PPI) network to identify hub genes and determine their correlation with immune cell infiltration using CIBERSORT. Real-time quantitative polymerase chain reaction (RT-qPCR), western blot, and immunohistochemical staining were implemented to verify identified hub genes in vivo. Simultaneously, we evaluated the prognostic relevance of the hub gene using clinical data. We determined COL1A1, COL1A2, and BGN to be the central hub genes in thymoma. Validation via RT-qPCR, Western blot, and immunohistochemical staining established significant statistical divergence between thymoma tissue and the normal thymus for only BGN. Expression levels of BGN showed strong negative correlation with the infiltration level of B cells and CD4+ T cells, yet a significant positive correlation with the level of neutrophil infiltration. We found high immune infiltration levels of macrophages, NK cells, and Th1 cells in the thymoma microenvironment in patients with a high expression of BGN. Co-localization of BGN and macrophages within thymoma tissue was discerned via tissue staining. Clinical data dictated that thymoma patients exhibiting elevated BGN expression underwent longer hospital stays, longer lengths in intensive care units, greater hospitalization costs, and extended ventilator usage; our study, augmented by clinical information, recognized BGN as possessive of diagnostic and prognostic significance in thymoma through in silico and molecular verification experiments. Our findings offered an important objective for thymoma-treated autoimmune disease comprehension, supplemented by the strong association with immune infiltration.

Decoding the complexity of delayed wound healing following Enterococcus faecalis infection

Wound infections are highly prevalent and can lead to delayed or failed healing, causing significant morbidity and adverse economic impacts. These infections occur in various contexts, including diabetic foot ulcers, burns, and surgical sites. Enterococcus faecalis is often found in persistent non-healing wounds, but its contribution to chronic wounds remains understudied. To address this, we employed single-cell RNA sequencing (scRNA-seq) on infected wounds in comparison to uninfected wounds in a mouse model. Examining over 23,000 cells, we created a comprehensive single-cell atlas that captures the cellular and transcriptomic landscape of these wounds. Our analysis revealed unique transcriptional and metabolic alterations in infected wounds, elucidating the distinct molecular changes associated with bacterial infection compared to the normal wound healing process. We identified dysregulated keratinocyte and fibroblast transcriptomes in response to infection, jointly contributing to an anti-inflammatory environment. Notably, E. faecalis infection prompted a premature, incomplete epithelial-mesenchymal transition in keratinocytes. Additionally, E. faecalis infection modulated M2-like macrophage polarization by inhibiting pro-inflammatory resolution in vitro, in vivo, and in our scRNA-seq atlas. Furthermore, we discovered macrophage crosstalk with neutrophils, which regulates chemokine signaling pathways, while promoting anti-inflammatory interactions with endothelial cells. Overall, our findings offer new insights into the immunosuppressive role of E. faecalis in wound infections.

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.

Small leucine rich proteoglycans: Biology, function and their therapeutic potential in the ocular surface

Small leucine rich proteoglycans (SLRPs) are the largest family of proteoglycans, with 18 members that are subdivided into five classes. SLRPs are small in size and can be present in tissues as glycosylated and non-glycosylated proteins, and the most studied SLRPs include decorin, biglycan, lumican, keratocan and fibromodulin. SLRPs specifically bind to collagen fibrils, regulating collagen fibrillogenesis and the biomechanical properties of tissues, and are expressed at particularly high levels in fibrous tissues, such as the cornea. However, SLRPs are also very active components of the ECM, interacting with numerous growth factors, cytokines and cell surface receptors. Therefore, SLRPs regulate major cellular processes and have a central role in major fundamental biological processes, such as maintaining corneal homeostasis and transparency and regulating corneal wound healing. Over the years, mutations and/or altered expression of SLRPs have been associated with various corneal diseases, such as congenital stromal corneal dystrophy and cornea plana. Recently, there has been great interest in harnessing the various functions of SLRPs for therapeutic purposes. In this comprehensive review, we describe the structural features and the related functions of SLRPs, and how these affect the therapeutic potential of SLRPs, with special emphasis on the use of SLRPs for treating ocular surface pathologies.

Stroma biglycan expression can be a prognostic factor in prostate cancers

OBJECTIVES

This study analyzes the relationship between biglycan expression in prostate cancer and clinicopathological parameters to clarify the potential link between biglycan and prognosis and progression to castration-resistant prostate cancer (CRPC).

METHODS

We retrospectively analyzed 60 cases of prostate cancer patients who underwent robot-assisted laparoscopic radical prostatectomy in Hokkaido University Hospital.

RESULTS

Biglycan was expressed in the tumor stroma but not in tumor cells. There was no significant relationship with biochemical recurrence (p = 0.5237), but the expression of biglycan was 36.1% in the group with progression to CRPC. This indicates a significant relationship with progression to CRPC (p = 0.0182). Furthermore, the expression of biglycan-positive blood vessels was significantly higher (15.9%) in the group with biochemical recurrence than in the group without biochemical recurrence (8.5%) (p = 0.0169). The biglycan-positive vessels were 28.6% in the group with progression to CRPC, which was significantly higher than that in the group without progression to CRPC (p < 0.0001).

CONCLUSION

This is the first study to show that stroma biglycan is a useful prognostic factor for prostate cancer.

Proteomics investigation of human sera for determination of postoperative indicators of pulmonary cystic echinococcosis

BACKGROUND

Cystic echinococcosis (CE)/hydatidosis is an important zoonotic parasitic disease caused by the larval stage of Echinococcus granulosus. The disease is a major health problem all over the world. Finding specific and sensitive biomarkers for follow-up of CE in patients after surgery is essential. Using proteomics methods, the present study aimed to evaluate post-surgical treatment by finding probable biomarker/s in the serum of human lungs CE.

METHODS

A total of 24 human sera were tested. These sera included eight confirmed lung/s CE patients sera before surgery (BS), eight sera 12 months post-surgery (12MPS) as well as eight control sera from healthy people. Proteomics methods including 2DE and LC-MS/MS were performed on the specimens followed by bioinformatics analysis. Differentially expressed proteins (DEP) were detected and, separately integrated with protein-protein interaction (PPI) data to construct the PPI network.

RESULTS

A total of 171 protein spots were detected in three groups including BS, 12MPS, and control groups; of which a total of 106 DEP have been expressed based on fold changes > = 2 and p-value < 0.05. More analysis was performed and a total of 10 protein spots were selected for identification by mass spectrometry showing the following proteins: APOA1, BGN, SPP2, EAF1, ACOXL, MRPL55, MCTP2, SEPTIN1, B4GALNT1, and ZNF843. Based on centrality parameters of the PPI network (degree and betweenness) five Hub-bottlenecks proteins with significant centrality values were found including APOA1, BGN, SPP2, EAF1, and ACOXL.

CONCLUSION

This study showed five proteins as hub-bottleneck proteins; of which APOA1 was more prominent. It can be concluded that a change in expression of this protein in patients' sera could be used as an indicator tool for the achievement of lungs CE surgical therapy.

BGN/FAP/STAT3 positive feedback loop mediated mutual interaction between tumor cells and mesothelial cells contributes to peritoneal metastasis of gastric cancer

Peritoneal metastasis (PM) is most frequent in gastric cancer (GC) and cancer-associated fibroblasts (CAFs) play a critical role in this process. However, the concrete mechanism of crosstalk between CAFs and cancer cells in PM of GC remains unclear. Microarray sequencing of GC focus and PM lesions was performed, and biglycan (BGN) was screened for further study. Clinically, BGN expression was higher in GC tissues than adjacent normal tissues, and high expression correlated with poor prognosis. In vitro experiments demonstrated that BGN promoted tumor progression and the transformation of mesothelial cells (MCs) into cancer-associated fibroblasts like cells (CAFLCs). In turn, CAFLCs-derived fibroblast activation protein (FAP) facilitated the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of GC cells. GC-derived BGN combined with toll like receptor 2 (TLR2)/TLR4 on MCs to activate the NF-κB pathway and promote the transformation of MCs into CAFLCs by the recovery experiment, coimmunoprecipitation assay, nuclear and cytoplasmic protein extraction assay. CAFLCs-derived FAP could activate the JAK2/STAT3 signaling pathway in GC. Finally, activated STAT3 promoted BGN transcription in GC, resulting in a BGN/FAP-STAT3 positive feedback loop. Taken together, mutual interaction between tumor cells and activated MCs mediated by a BGN/FAP-STAT3 positive feedback loop facilitates PM of GC and provides a potential biomarker and therapeutic target for GC metastasis.

Screening prognostic genes related to leucovorin, fluorouracil, and irinotecan treatment sensitivity by performing co-expression network analysis for colon cancer

Background: Colon cancer is one of the most common malignant tumors in the world. FOLFIRI (leucovorin, fluorouracil, and irinotecan) is a common combination in chemotherapy regimens. However, insensitivity to FOLFIRI is an important factor in the effectiveness of the treatment for advanced colon cancer. Our study aimed to explore precise molecular targets associated with chemotherapy responses in colon cancer.

Methods: Gene expression profiles of 21 patients with advanced colorectal cancer who received chemotherapy based on FOLFIRI were obtained from the Gene Expression Omnibus (GEO) database. The gene co-expression network was constructed by the weighted gene co-expression network analysis (WGCNA) and functional gene modules were screened out. Clinical phenotypic correlation analysis was used to identify key gene modules. Gene Ontology and pathway enrichment analysis were used to screen enriched genes in key modules. Protein–protein interaction (PPI) analysis was used to screen out key node genes. Based on the Gene Expression Profiling Interactive Analysis (GEPIA) database, the correlation between the expression levels of these genes and the overall survival (OS) and disease-free survival (DFS) of colon cancer patients was investigated, and the hub genes were screened out. Immunohistochemistry of candidate hub genes was identified using the Human Protein Atlas database. Finally, clinical information and RNA sequencing data of colon cancer were obtained from The Cancer Genome Atlas project database (TCGA), the GEPIA, and the Human Atlas databases for validation.

Results: The WGCNA revealed that three hub genes were closely related to chemotherapy insensitivity of colon cancer: AEBP1, BGN, and TAGLN. The protein expression levels of AEBP1, BGN, and TAGLN in tumor tissues were higher than those in normal tissues. In addition, the gene expression levels of AEBP1, BGN, and TAGLN were negatively correlated with OS and DFS in colon cancer patients. Therefore, AEBP1, BGN, and TAGLN have been identified as potential biomarkers related to the response to FOLFIRI treatment of colon cancer.

Conclusion: We found that AEBP1, BGN, and TAGLN, as potential predictive biomarkers, may play an important role in the response to FOLFIRI treatment of colon cancer and as a precise molecular target associated with chemotherapy response in colon cancer.

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.

The oxidized-LDL/LOX-1 axis in tumor endothelial cells enhances metastasis by recruiting neutrophils and cancer cells

Epidemiological relationships between cancer and cardiovascular diseases have been reported, but a molecular basis remains unclear. Some proteoglycans that strongly bind low-density-lipoprotein (LDL) are abundant both in atherosclerotic regions and in high metastatic-tumor tissue. LDL retention is crucial for the initiation of atherosclerosis, although its contribution to malignancy of cancer is not known. In this study, we show the importance of the accumulation of LDL in tumor metastasis. We demonstrated that high metastatic-tumor tissue contains high amounts of LDL and forms more oxidized LDL (ox-LDL). Interestingly, lectin-like ox-LDL receptor 1 (LOX-1), a receptor for ox-LDL and a recognized key molecule for cardiovascular diseases, was highly expressed in tumor endothelial cells (TECs). Neutrophils are important for ox-LDL formation. Since we observed the accumulation and activation of neutrophils in HM-tumors, we evaluated the involvement of LOX-1 in neutrophil migration and activation. LOX-1 induced neutrophil migration via CCL2 secretion from TECs, which was enhanced by ox-LDL. Finally, we show genetic manipulation of LOX-1 expression in TECs or tumor stroma tended to reduce lung metastasis. Thus, the LOX-1/ox-LDL axis in TECs may lead to the formation of a high metastatic-tumor microenvironment via attracting neutrophils. This article is protected by copyright. All rights reserved.

Novel antiangiogenic therapy targeting biglycan using tumor endothelial cell-specific liposomal siRNA delivery system

Tumor blood vessels play important roles in tumor progression and metastasis. Targeting tumor endothelial cells (TECs) is one of the strategies for cancer therapy. We previously reported that biglycan, a small leucine‐rich proteoglycan, is highly expressed in TECs. TECs utilize biglycan in an autocrine manner for migration and angiogenesis. Furthermore, TEC‐derived biglycan stimulates tumor cell migration in a paracrine manner leading to tumor cell intravasation and metastasis. In this study, we explored the therapeutic effect of biglycan inhibition in the TECs of renal cell carcinoma using an in vivo siRNA delivery system known as a multifunctional envelope‐type nanodevice (MEND), which contains a unique pH‐sensitive cationic lipid. To specifically deliver MEND into TECs, we incorporated cyclo(Arg–Gly–Asp–d–Phe–Lys) (cRGD) into MEND because α_Vβ₃ integrin, a receptor for cRGD, is selective and highly expressed in TECs. We developed RGD‐MEND‐encapsulating siRNA against biglycan. First, we confirmed that MEND was delivered into OS‐RC‐2 tumor‐derived TECs and induced in vitro RNAi‐mediated gene silencing. MEND was then injected intravenously into OS‐RC‐2 tumor‐bearing mice. Flow cytometry analysis demonstrated that MEND was specifically delivered into TECs. Quantitative RT‐PCR indicated that biglycan was knocked down by biglycan siRNA‐containing MEND. Finally, we analyzed the therapeutic effect of biglycan silencing by MEND in TECs. Tumor growth was inhibited by biglycan siRNA‐containing MEND. Tumor microenvironmental factors such as fibrosis were also normalized using biglycan inhibition in TECs. Biglycan in TECs can be a novel target for cancer treatment.

Crosstalk of tumor stromal cells orchestrates invasion and spreading of gastric cancer

Tumors contain various stromal cells that support cancer progression. Some types of cancer, such as scirrhous gastric cancer, are characterized by large areas of fibrosis accompanied by cancer-associated fibroblasts (CAFs). Asporin (ASPN) is a small leucine-rich proteoglycan highly expressed in CAFs of various tumors. ASPN accelerates CAF migration and invasion, resulting in CAF-led cancer cell invasion. In addition, ASPN further upregulated the expression of genes specific to a characteristic subgroup of fibroblasts in tumors. These cells were preferentially located at the tumor periphery and could be generated by a unique mechanism involving the CAF-mediated education of normal fibroblasts (CEFs). In this review, we at first describe recent findings regarding the function of ASPN in the tumor microenvironment, as well as the mechanism involved in the generation of CEFs. CAFs are derived from heterogeneous origins besides resident normal fibroblasts. Among them, CAFs derived from mesothelial cells (mesothelial cell-derived CAF [MC-CAFs]) play pivotal roles in peritoneal carcinomatosis. We observed that MC-CAFs on the surfaces of organs also participate in tumor formation by infiltrating into the parenchyma, promoting local invasion by gastric cancers. This review also highlights the potential functions of macrophages in the formation of MC-CAFs in gastric cancers, by transfer the contents of cancer cell-derived extracellular vesicles.

Identification and Validation of Biglycan as Prognosis and Therapy Markers for Patients with Stomach Adenocarcinoma

OBJECTIVE

Previous studies have confirmed the biglycan (BGN) as a core gene in stomach adenocarcinoma (STAD). Present study aimed at conducting further investigations to reveal the potential function of BGN in STAD.

METHODS

The mRNA and protein expressions of BGN in STAD were firstly evaluated, followed by immune infiltration analyses. The influence of BGN expression on the overall survival of STAD patients was subsequently analyzed, and a restrict survival analysis was performed as well. The protein-protein interaction (PPI) network analysis on the co-expressed genes with BGN was finally adopted to obtain the most important module in the whole network, and significant Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway associated with hub genes within the main module was further predicted.

RESULTS

(1) We verified the mRNA high expression of BGN in STAD (all P<0.05), and higher expression was observed in patients with stage 4 (P<0.001) and grade 3 (P<0.001). The BGN protein was mainly localized to the golgi apparatus, and protein expression displayed an individual difference. (2) Immune infiltration analysis showed the strongest correlation between BGN expression and abundance of natural killer cell (P<0.001), Transforming Growth Factor beta 1 (TGFB1) (P<0.001), TNF Receptor Superfamily Member 4 (TNFRSF4) (P<0.001) and C-X-C Motif Chemokine Ligand 12 (CXCL12) (P<0.001) in STAD. BGN expression was also correlated to immune subtypes (P=0.0347) and molecular subtypes (P=0.0263) in STAD. (3) High expression of BGN shortened the overall survival time of STAD patients (all P<0.01). The influence of BGN expression on the prognosis was statistically affected by several clinical phenotypes and cohorts of patients. Cox regression showed that BGN can be considered as a prognostic predictor of STAD (P<0.05). (4) Pathway analysis indicated that BGN possibly participated in ECM-receptor interaction, focal adhesion, human papillomavirus infection and PI3K-Akt signaling pathway (all P<0.001).

CONCLUSION

BGN was highly expressed in STAD, implying a poor prognosis of patients. Relevant signal pathways associated with BGN were distinguished as well. BGN could be used as a potential therapeutic biomarker for STAD.

The Role of IGF/IGF-IR-Signaling and Extracellular Matrix Effectors in Bone Sarcoma Pathogenesis

Simple Summary

Bone sarcomas are mesenchymal origin tumors. Bone sarcoma patients show a variable response or do not respond to chemotherapy. Notably, improving efficient chemotherapy approaches, dealing with chemoresistance, and preventing metastasis pose unmet challenges in sarcoma therapy. Insulin-like growth factors 1 and 2 (IGF-1 and -2) and their respective receptors are a multifactorial system that significantly contributes to bone sarcoma pathogenesis. Most clinical trials aiming at the IGF pathway have had limited success. Developing combinatorial strategies to enhance antitumor responses and better classify the patients that could best benefit from IGF-axis targeting therapies is in order. A plausible approach for developing a combinatorial strategy is to focus on the tumor microenvironment (TME) and processes executed therein. Herewith, we will discuss how the interplay between IGF-signaling and the TME constituents affects bone sarcomas’ basal functions and their response to therapy. Potential direct and adjunct therapeutical implications of the extracellular matrix (ECM) effectors will also be summarized.

Abstract

Bone sarcomas, mesenchymal origin tumors, represent a substantial group of varying neoplasms of a distinct entity. Bone sarcoma patients show a limited response or do not respond to chemotherapy. Notably, developing efficient chemotherapy approaches, dealing with chemoresistance, and preventing metastasis pose unmet challenges in sarcoma therapy. Insulin-like growth factors 1 and 2 (IGF-1 and -2) and their respective receptors are a multifactorial system that significantly contributes to bone sarcoma pathogenesis. Whereas failures have been registered in creating novel targeted therapeutics aiming at the IGF pathway, new agent development should continue, evaluating combinatorial strategies for enhancing antitumor responses and better classifying the patients that could best benefit from these therapies. A plausible approach for developing a combinatorial strategy is to focus on the tumor microenvironment (TME) and processes executed therein. Herewith, we will discuss how the interplay between IGF-signaling and the TME constituents affects sarcomas’ basal functions and their response to therapy. This review highlights key studies focusing on IGF signaling in bone sarcomas, specifically studies underscoring novel properties that make this system an attractive therapeutic target and identifies new relationships that may be exploited. Potential direct and adjunct therapeutical implications of the extracellular matrix (ECM) effectors will also be summarized.

Inhibition of stromal biglycan promotes normalization of the tumor microenvironment and enhances chemotherapeutic efficacy

BACKGROUND

Biglycan is a proteoglycan found in the extracellular matrix. We have previously shown that biglycan is secreted from tumor endothelial cells and induces tumor angiogenesis and metastasis. However, the function of stroma biglycan in breast cancer is still unclear.

METHODS

Biglycan gene analysis and its prognostic values in human breast cancers were based on TCGA data. E0771 breast cancer cells were injected into WT and Bgn KO mice, respectively.

RESULTS

Breast cancer patients with high biglycan expression had worse distant metastasis-free survival. Furthermore, biglycan expression was higher in the tumor stromal compartment compared to the epithelial compartment. Knockout of biglycan in the stroma (Bgn KO) in E0771 tumor-bearing mice inhibited metastasis to the lung. Bgn KO also impaired tumor angiogenesis and normalized tumor vasculature by repressing tumor necrosis factor-ɑ/angiopoietin 2 signaling. Moreover, fibrosis was suppressed and CD8+ T cell infiltration was increased in tumor-bearing Bgn KO mice. Furthermore, chemotherapy drug delivery and efficacy were improved in vivo in Bgn KO mice.

CONCLUSION

Our results suggest that targeting stromal biglycan may yield a potent and superior anticancer effect in breast cancer.

Biglycan, tumor endothelial cell secreting proteoglycan, as possible biomarker for lung cancer

OBJECTIVES

In lung cancer, surgery remains the most curative treatment and limited resection is beneficial for patients with low cardiopulmonary function and low malignancy tumors. However, there are no biomarkers of low malignancy to select candidates for limited resection without compromising the outcome of treatments. Recently we identified biglycan (BGN) as a tumor endothelial cell (TEC) marker that is associated with tumor progression in various cancers. In this study, we analyzed the association between BGN expression in TECs in lung cancer and cancer progression in patients.

MATERIALS AND METHODS

First, we performed immunohistochemistry of BGN with resected lung tumor tissues of 155 patients who had undergone thoracic surgery and analyzed the correlation between BGN-positive vessel density in primary lung tumors and clinicopathological factors. Second, we measured the BGN levels in preoperative serum of other 46 patients with lung cancer by ELISA, and analyzed the correlation between BGN expression in tumor tissues and blood BGN levels.

RESULTS

High BGN expression in the TECs was significantly associated with T factor, and was a significant negative predictor. BGN levels in preoperative serum of 46 patients with lung cancer was significantly correlated with BGN expression in the TECs. Preoperative serum BGN level was significantly lower in healthy volunteers and less invasive adenocarcinoma than in invasive adenocarcinoma and other lung carcinomas. These results suggest that low BGN level in preoperative serum in patients with lung cancer might indicate low malignancy.

CONCLUSIONS

BGN can be a potential biomarker for lung cancer.