The Clinical Prognostic Value of LRG1 in Esophageal Squamous Cell Carcinoma

LRG1 and SDR16C5 protein expressions differ according to HPV status in oropharyngeal squamous cell carcinoma

The increasing incidence of oropharyngeal squamous cell carcinoma (OPSCC) is primarily due to human papillomavirus, and understanding the tumor biology caused by the virus is crucial. Our goal was to investigate the proteins present in the serum of patients with OPSCC, which were not previously studied in OPSCC tissue. We examined the difference in expression of these proteins between HPV-positive and -negative tumors and their correlation with clinicopathological parameters and patient survival. The study included 157 formalin-fixed, paraffin-embedded tissue samples and clinicopathological data. Based on the protein levels in the sera of OPSCC patients, we selected 12 proteins and studied their expression in HPV-negative and HPV-positive OPSCC cell lines. LRG1, SDR16C5, PIP4K2C and MVD proteins were selected for immunohistochemical analysis in HPV-positive and -negative OPSCC tissue samples. These protein´s expression levels were compared with clinicopathological parameters and patient survival to investigate their clinical relevance. LRG1 expression was strong in HPV-negative whereas SDR16C5 expression was strong in HPV-positive tumors. Correlation was observed between LRG1, SDR16C5, and PIP4K2C expression and patient survival. High expression of PIP4K2C was found to be an independent prognostic factor for overall survival and expression correlated with HPV-positive tumor status. The data suggest the possible role of LRG1, SDR16C5 and PIP4K2C in OPSCC biology.

Increased level of serum leucine-rich-alpha-2-glycoprotein 1 in patients with clear cell renal cell carcinoma

BACKGROUND

Currently, no useful serum markers exist for clear cell renal cell carcinoma (ccRCC), making early detection challenging as diagnosis relies solely on imaging tests. Radiation exposure is also a concern due to multiple required CT examinations during treatment. Renal cell carcinoma (RCC) histological types include ccRCC and non-clear cell RCC (non-ccRCC); however, treatment response to medications varies which necessitates accurate differentiation between the two. Therefore, we aimed to identify a novel serum marker of RCC. Increased LRG1 expression in the serum has been demonstrated in multiple cancer types. However, the expression of LRG1 expression in the serum and cancer tissues of patients with RCC has not been reported. Since ccRCC is a hypervascular tumor and LRG1 is capable of accelerating angiogenesis, we hypothesized that the LRG1 levels may be related to ccRCC. Therefore, we examined LRG1 expression in sera from patients with RCC.

METHODS

Using an enzyme-linked immunosorbent assay, serum levels of leucine-rich-alpha-2-glycoprotein 1 (LRG1) were measured in 64 patients with ccRCC and 22 patients non-ccRCC who underwent radical or partial nephrectomy, as well as in 63 patients without cancer.

RESULTS

Median values of serum LRG1 and their inter-quartile ranges were 63.2 (42.8-94.2) µg/mL in ccRCC, 23.4 (17.7-29.6) µg/mL in non-ccRCC, and 36.0 (23.7-56.7) µg/mL in patients without cancer, respectively (ccRCC vs. non-ccRCC or patients without cancer: P < 0.001). C-reactive protein (CRP) levels (P = 0.002), anemia (P = 0.037), hypercalcemia (P = 0.023), and grade (P = 0.031) were independent predictors of serum LRG1 levels in ccRCC. To assess diagnostic performance, the area under the receiver operating characteristic curve of serum LRG1 was utilized to differentiate ccRCC from non-cancer and non-ccRCC, with values of 0.73 (95% CI, 0.64-0.82) and 0.91 (95% CI, 0.82-0.96), respectively.

CONCLUSIONS

LRG1 served as a serum marker associated with inflammation, indicated by CRP, anemia, hypercalcemia, and malignant potential in ccRCC. Clinically, serum LRG1 levels may assist in differentiating ccRCC from non-ccRCC with excellent diagnostic accuracy.

The possibilities of LOXL4 as a prognostic marker for carcinomas

Lysyl oxidase-like 4 (LOXL4), a member of lysyl oxidase family, is a copper and lysine tyrosylquinone-dependent amine oxidase that serves the role of catalyzing the cross-linking of elastin and collagen in the extracellular matrix. Numerous studies have shown a significant association between LOXL4 expression levels and tumor proliferation, migration, invasion and patients' prognosis and overall survival in different types of tumors. Here we review their relationship and the molecular pathogenesis behind them, aiming to explore the possibilities of LOXL4 as a prognostic marker for diverse carcinomas and provide some indications for further research in this field.

Cross-platform validation of a mouse blood gene signature for quantitative reconstruction of radiation dose

In the search for biological markers after a large-scale exposure of the human population to radiation, gene expression is a sensitive endpoint easily translatable to in-field high throughput applications. Primarily, the ex-vivo irradiated healthy human blood model has been used to generate available gene expression datasets. This model has limitations i.e., lack of signaling from other irradiated tissues and deterioration of blood cells cultures over time. In vivo models are needed; therefore, we present our novel approach to define a gene signature in mouse blood cells that quantitatively correlates with radiation dose (at 1 Gy/min). Starting with available microarray datasets, we selected 30 radiation-responsive genes and performed cross-validation/training–testing data splits to downselect 16 radiation-responsive genes. We then tested these genes in an independent cohort of irradiated adult C57BL/6 mice (50:50 both sexes) and measured mRNA by quantitative RT-PCR in whole blood at 24 h. Dose reconstruction using net signal (difference between geometric means of top 3 positively correlated and top 4 negatively correlated genes with dose), was highly improved over the microarrays, with a root mean square error of ± 1.1 Gy in male and female mice combined. There were no significant sex-specific differences in mRNA or cell counts after irradiation.

LRG1 in pancreatic cancer cells promotes inflammatory factor synthesis and the angiogenesis of HUVECs by activating VEGFR signaling

BACKGROUND

This study aimed to investigate the roles of leucine-rich alpha-2-glycoprotein 1 (LRG1) in regulating angiogenesis during pancreatic cancer (PC) pathogenesis.

METHODS

LRG1 expression in tissues was detected by qRT-PCR and immunohistochemistry. LRG1 in BxPC-3 and Capan-2 cells was knocked down or overexpressed. Cell viability and the migration and invasion abilities of cells were analyzed using the Cell Counting Kit-8 (CCK-8) assay and Transwell system, respectively. Interleukin-1 beta (IL-1β), IL-18, and vascular endothelial growth factor A (VEGFA) contents in cell culture were measured by ELISA, and the angiogenesis of HUVECs was assessed by the in vitro tube formation assay. In vitro LRG1 expression in BxPC-3 and Capan-2 cells was determined using immunofluorescence.

RESULTS

The results showed that LRG1 expression was significantly increased in pancreatic cancer tissues and cell lines. LRG1 knockdown inhibited the viability, migration, invasion, and IL-1β and IL-18 synthesis of BxPC-3 and Capan-2 cells. VEGFA synthesis in BxPC-3 and Capan-2 cells was also inhibited by LRG1 knockdown, which caused impaired tube formation of co-cultured HUVECs. LRG1 overexpression enhanced the viability, migration, and invasion of BxPC-3 and Capan-2 cells, also causing elevated tube formation of HUVECs and IL-1β and IL-18 synthesis in co-cultures of HUVECs and BxPC-3 or Capan-2 cells. Silencing of VEGF receptor (VEGFR) abrogated the enhanced tube formation and IL-1β and IL-18 synthesis in HUVECs co-cultured with BxPC-3 or Capan-2 cells overexpressing LRG1.

CONCLUSIONS

In conclusion, LRG1, which is highly expressed in pancreatic cancer cells, promotes inflammatory factor synthesis and the angiogenesis of HUVECs though activating the VEGFR signaling pathway.

Research Progress on Leucine-Rich Alpha-2 Glycoprotein 1: A Review

Leucine-rich alpha⁃2 glycoprotein 1 (LRG1) is an important member of the leucine-rich repetitive sequence protein family. LRG1 was mainly involved in normal physiological activities of the nervous system, such as synapse formation, synapse growth, the development of nerve processes, neurotransmitter transfer and release, and cell adhesion molecules or ligand-binding proteins. Also, LRG1 affected the development of respiratory diseases, hematological diseases, endocrine diseases, tumor diseases, eye diseases, cardiovascular diseases, rheumatic immune diseases, infectious diseases, etc. LRG1 was a newly discovered important upstream signaling molecule of transforming growth factor⁃β (TGF⁃β) that affected various pathological processes through the TGF⁃β signaling pathway. However, research on LRG1 and its involvement in the occurrence and development of diseases was still in its infancy and the current studies were mainly focused on proteomic detection and basic animal experimental reports. We could reasonably predict that LRG1 might act as a new direction and strategy for the treatment of many diseases.

LRG1: an emerging player in disease pathogenesis

The secreted glycoprotein leucine-rich α-2 glycoprotein 1 (LRG1) was first described as a key player in pathogenic ocular neovascularization almost a decade ago. Since then, an increasing number of publications have reported the involvement of LRG1 in multiple human conditions including cancer, diabetes, cardiovascular disease, neurological disease, and inflammatory disorders. The purpose of this review is to provide, for the first time, a comprehensive overview of the LRG1 literature considering its role in health and disease. Although LRG1 is constitutively expressed by hepatocytes and neutrophils, Lrg1-/- mice show no overt phenotypic abnormality suggesting that LRG1 is essentially redundant in development and homeostasis. However, emerging data are challenging this view by suggesting a novel role for LRG1 in innate immunity and preservation of tissue integrity. While our understanding of beneficial LRG1 functions in physiology remains limited, a consistent body of evidence shows that, in response to various inflammatory stimuli, LRG1 expression is induced and directly contributes to disease pathogenesis. Its potential role as a biomarker for the diagnosis, prognosis and monitoring of multiple conditions is widely discussed while dissecting the mechanisms underlying LRG1 pathogenic functions. Emphasis is given to the role that LRG1 plays as a vasculopathic factor where it disrupts the cellular interactions normally required for the formation and maintenance of mature vessels, thereby indirectly contributing to the establishment of a highly hypoxic and immunosuppressive microenvironment. In addition, LRG1 has also been reported to affect other cell types (including epithelial, immune, mesenchymal and cancer cells) mostly by modulating the TGFβ signalling pathway in a context-dependent manner. Crucially, animal studies have shown that LRG1 inhibition, through gene deletion or a function-blocking antibody, is sufficient to attenuate disease progression. In view of this, and taking into consideration its role as an upstream modifier of TGFβ signalling, LRG1 is suggested as a potentially important therapeutic target. While further investigations are needed to fill gaps in our current understanding of LRG1 function, the studies reviewed here confirm LRG1 as a pleiotropic and pathogenic signalling molecule providing a strong rationale for its use in the clinic as a biomarker and therapeutic target.

The role of leucine-rich alpha-2-glycoprotein-1 in proliferation, migration, and invasion of tumors

BACKGROUND

Leucine-rich alpha-2-glycoprotein-1 (LRG1) is widely involved in proliferation, migration, and invasion of various tumor cells. Recent studies have evaluated the potential of LRG1 as both an early tumor and a prognostic biomarker.

METHOD

The relevant literature from PubMed is reviewed in this article.

RESULTS

It has been found that LRG1 mainly acts on the regulatory mechanisms of angiogenesis, epithelial-mesenchymal transition (EMT), and apoptosis by transforming growth factor (TGF-β) signaling pathway as well as affecting the occurrence and development of the tumors. Moreover, with advancement of research, LRG1 regulation pathways which are independent of TGF-β signaling pathway have been gradually revealed in different tumor cells; There are several studies on the biological effects of LRG1 as an inflammatory factor, vascular growth regulator, cell adhesion, and a cell viability influencing factor. In addition, various tumor suppression methods which are based on regulation of LRG1 levels have also shown high potential clinical value.

CONCLUSIONS

LRG1 are critical for the processes of tumorigenesis, development, and metastasis in various tumors. The present study reviewed the latest research on the achievements of LRG1 in tumor genesis and development. Further, this study also discussed the related molecular mechanisms of various biological functions of LRG1.

LRG1 destabilizes tumor vessels and restricts immunotherapeutic potency

BACKGROUND

A poorly functioning tumor vasculature is pro-oncogenic and may impede the delivery of therapeutics. Normalizing the vasculature, therefore, may be beneficial. We previously reported that the secreted glycoprotein leucine-rich α-2-glycoprotein 1 (LRG1) contributes to pathogenic neovascularization. Here, we investigate whether LRG1 in tumors is vasculopathic and whether its inhibition has therapeutic utility.

METHODS

Tumor growth and vascular structure were analyzed in subcutaneous and genetically engineered mouse models in wild-type and Lrg1 knockout mice. The effects of LRG1 antibody blockade as monotherapy, or in combination with co-therapies, on vascular function, tumor growth, and infiltrated lymphocytes were investigated.

FINDINGS

In mouse models of cancer, Lrg1 expression was induced in tumor endothelial cells, consistent with an increase in protein expression in human cancers. The expression of LRG1 affected tumor progression as Lrg1 gene deletion, or treatment with a LRG1 function-blocking antibody, inhibited tumor growth and improved survival. Inhibition of LRG1 increased endothelial cell pericyte coverage and improved vascular function, resulting in enhanced efficacy of cisplatin chemotherapy, adoptive T cell therapy, and immune checkpoint inhibition (anti-PD1) therapy. With immunotherapy, LRG1 inhibition led to a significant shift in the tumor microenvironment from being predominantly immune silent to immune active.

CONCLUSIONS

LRG1 drives vascular abnormalization, and its inhibition represents a novel and effective means of improving the efficacy of cancer therapeutics.

FUNDING

Wellcome Trust (206413/B/17/Z), UKRI/MRC (G1000466, MR/N006410/1, MC/PC/14118, and MR/L008742/1), BHF (PG/16/50/32182), Health and Care Research Wales (CA05), CRUK (C42412/A24416 and A17196), ERC (ColonCan 311301 and AngioMature 787181), and DFG (CRC1366).

Detection of leucine-rich alpha-2-glycoprotein 1-containing immunocomplexes in the plasma of lung cancer patients with epitope-specific mAbs

BACKGROUND

Lung cancer is the leading cause of cancer-related deaths worldwide. With the expectation of improved survival, tremendous efforts and resources have been invested in the discovery of specific biomarkers for early detection of the disease. Several investigators have reported the presence of cancer-associated autoantibodies in the plasma or serum of lung cancer patients. Previously, we used a monoclonal-antibody proteomics technology platform for the discovery of novel lung cancer-associated proteins.

OBJECTIVE

The identification of specific protein epitopes associated with various cancers is a promising method in biomarker discovery. Here, in a preliminary study, we aimed to detect autoantibody-leucine-rich alpha-2-glycoprotein 1 (LRG1) immunocomplexes using epitope-specific monoclonal antibodies (mAbs).

METHODS

We performed sandwich ELISA assays using the LRG1 epitope-specific capture mAbs, Bsi0352 and Bsi0392, and an IgG-specific polyclonal antibody coupled to a reporter system as the detection reagent. We tested the plasma of lung-cancer patients and apparently healthy controls.

RESULTS

Depending on the epitope specificity of the capture monoclonal mAb, we were either unable to distinguish the control from LC-groups or showed a higher level of LRG1 and IgG autoantibody containing immunocomplexes in the plasma of non-small cell lung cancer and small cell lung cancer subgroups of lung cancer patients than in the plasma of control subjects.

CONCLUSIONS

Our findings underline the importance of protein epitope-specific antibody targeted approaches in biomarker research, as this may increase the accuracy of previously described tests, which will need further validation in large clinical cohorts.

LRG1 Expression Is Elevated in the Eyes of Patients with Neovascular Age-Related Macular Degeneration

Leucine-rich a-2-glycoprotein 1 (LRG1) is a candidate therapeutic target for treating the neovascular form of age-related macular degeneration (nvAMD). In this study we examined the expression of LRG1 in eyes of nvAMD patients. Choroidal neovascular membranes (CNVMs) from patients who underwent submacular surgery for retinal pigment epithelium-choroid graft transplantation were collected from 5 nvAMD patients without any prior intravitreal anti-VEGF injection, and from six patients who received intravitreal anti-VEGF injections before surgery. As controls free of nvAMD, retina sections were obtained from the eyes resected from a patient with lacrimal sac tumor and from a patient with neuroblastoma. CNVMs were immunostained for CD34, LRG1, and α-smooth muscle actin (α-SMA). Aqueous humor samples were collected from 58 untreated-naïve nvAMD patients prior to the intravitreal injection of anti-VEGF and 51 age-matched cataract control patients, and LRG1 concentration was measured by ELISA. The level of LRG1 immunostaining is frequently high in both the endothelial cells of the blood vessels, and myofibroblasts in the surrounding tissue of CNVMs of treatment-naïve nvAMD patients. Furthermore, the average concentration of LRG1 was significantly higher in the aqueous humor of nvAMD patients than in controls. These observations provide a strong experimental basis and scientific rationale for the progression of a therapeutic anti-LRG1 monoclonal antibody into clinical trials with patients with nvAMD.

The Multipotential of Leucine-Rich α-2 Glycoprotein 1 as a Clinicopathological Biomarker of Glioblastoma

Leucine-rich α-2 glycoprotein 1 (LRG1) is a diagnostic marker candidate for glioblastoma. Although LRG1 has been associated with angiogenesis, it has been suggested that its biomarker role differs depending on the type of tumor. In this study, a clinicopathological examination of LRG1's role as a biomarker for glioblastoma was performed. We used tumor tissues of 155 cases with diffuse gliomas (27 astrocytomas, 14 oligodendrogliomas, 114 glioblastomas). The immunohistochemical LRG1 intensity scoring was classified into 2 groups: low expression and high expression. Mutations of IDH1, IDH2, and TERT promoter were analyzed through the Sanger method. We examined the relationship between LRG1 expression level in glioblastoma and clinical parameters, such as age, preoperative Karnofsky performance status, tumor location, extent of resection, O6-methylguanine DNA methyltransferase promoter, and prognosis. LRG1 high expression rate was 41.2% in glioblastoma, 3.7% in astrocytoma, and 21.4% in oligodendroglioma. Glioblastoma showed a significantly higher LRG1 expression than lower-grade glioma (p = 0.0003). High expression of LRG1 was an independent favorable prognostic factor (p = 0.019) in IDH-wildtype glioblastoma and correlated with gross total resection (p = 0.002) and the tumor location on nonsubventricular zone (p = 0.00007). LRG1 demonstrated multiple potential as a diagnostic, prognostic, and regional biomarker for glioblastoma.

MicroRNA-497 elevation or LRG1 knockdown promotes osteoblast proliferation and collagen synthesis in osteoporosis via TGF-β1/Smads signalling pathway

MicroRNAs (miRNAs) have been corroborated to engage in the process of cellular activities in osteoporosis. However, few researches have been conducted to expose the integrated role of miR‐497, leucine‐rich alpha‐2‐glycoprotein‐1 (LRG1) and transforming growth factor beta 1 (TGF‐β1)/Smads signalling pathway in osteoporosis. Thereafter, the study is set out to delve into miR‐497/LRG1/TGF‐β1/Smads signalling pathway axis in osteoporosis. Osteoporosis bone tissues and normal bone tissues were collected. Rat osteoporosis models were constructed via ovariectomy. Model rats were injected with restored miR‐497 or depleted LRG1 to explore their roles in osteoporosis. Rat osteoblasts were extracted from osteoporosis rats and transfected with restored miR‐497 or depleted LRG1 for further verification. MiR‐497 and LRG1 expression in femoral head tissues and osteoblasts of osteoporosis rats were detected. TGF‐β1/Smads signalling pathway‐related factors were detected. MiR‐497 was poorly expressed while LRG1 was highly expressed and TGF‐β1/Smads signalling pathway activation was inhibited in osteoporosis. MiR‐497 up‐regulation or LRG1 down‐regulation activated TGF‐β1/Smads signalling pathway, promoted collagen type 1 synthesis and suppressed oxidative stress in femoral head tissues in osteoporosis. MiR‐497 restoration or LRG1 knockdown activated TGF‐β1/Smads signalling pathway, promoted viability and suppressed apoptosis of osteoblasts in osteoporosis. Our study suggests that miR‐497 up‐regulation or LRG1 down‐regulation promotes osteoblast viability and collagen synthesis via activating TGF‐β1/Smads signalling pathway, which may provide a novel reference for osteoporosis treatment.

Identification of candidate aberrantly methylated and differentially expressed genes in Esophageal squamous cell carcinoma

Aberrant methylated genes (DMGs) play an important role in the etiology and pathogenesis of esophageal squamous cell carcinoma (ESCC). In this study, we aimed to integrate three cohorts profile datasets to ascertain aberrant methylated-differentially expressed genes and pathways associated with ESCC by comprehensive bioinformatics analysis. We downloaded data of gene expression microarrays (GSE20347, GSE38129) and gene methylation microarrays (GSE52826) from the Gene Expression Omnibus (GEO) database. Aberrantly differentially expressed genes (DEGs) were obtained by GEO2R tool. The David database was then used to perform Gene ontology (GO) analysis and Kyoto Encyclopedia of Gene and Genome pathway enrichment analyses on selected genes. STRING and Cytoscape software were used to construct a protein-protein interaction (PPI) network, then the modules in the PPI networks were analyzed with MCODE and the hub genes chose from the PPI networks were verified by Oncomine and TCGA database. In total, 291 hypomethylation-high expression genes and 168 hypermethylation-low expression genes were identified at the screening step, and finally found six mostly changed hub genes including KIF14, CDK1, AURKA, LCN2, TGM1, and DSG1. Pathway analysis indicated that aberrantly methylated DEGs mainly associated with the P13K-AKT signaling, cAMP signaling and cell cycle process. After validation in multiple databases, most hub genes remained significant. Patients with high expression of AURKA were associated with shorter overall survival. To summarize, we have identified six feasible aberrant methylated-differentially expressed genes and pathways in ESCC by bioinformatics analysis, potentially providing valuable information for the molecular mechanisms of ESCC. Our data combined the analysis of gene expression profiling microarrays and gene methylation profiling microarrays, simultaneously, and in this way, it can shed a light for screening and diagnosis of ESCC in future.

The secretome of skin cancer cells activates the mTOR/MYC pathway in healthy keratinocytes and induces tumorigenic properties

Cutaneous squamous cell carcinoma (cSCC) is the most prominent tumor of non-melanoma skin cancers and the most aggressive tumor among keratinocyte carcinoma of the skin, showing a high potential for local invasion and metastasis. The cSCC incidences increased dramatically in recent years and the disease occurs more commonly than any other malignancy. The secretome of cancer cells is currently the focus of many studies in order to identify new marker proteins for different types of cancer and to investigate its influence on the tumor microenvironment. In our study we evaluated whether the secretome of cSCC cells has an impact on keratinocytes, the surrounding tissue cells of cSCC. Therefore, we analyzed and compared the secretome of human A431 cancer cells and of HaCaT keratinocytes by mass spectrometry. In a second experiment, keratinocytes were exposed to the secretome of A431 cells and vice versa and the transcriptome was analyzed by next-generation sequencing. HaCaT cells incubated with A431 conditioned medium revealed a significantly activated mammalian target of rapamycin pathway with a concomitant increase in proliferation and migration. In conclusion, our data demonstrate the impact of the secretome of cancer cells on the transcription machinery of the cells surrounding the tumor, leading to a tumorigenic cell fate.

LRG1 Suppresses Migration and Invasion of Esophageal Squamous Cell Carcinoma by Modulating Epithelial to Mesenchymal Transition

Background: Esophageal squamous cell carcinoma (ESCC) is a common cancer with poor prognosis. The molecular pathogenesis underlying ESCC remains to be explored. Leucine-rich ɑ-2-glycoprotein 1 (LRG1) has been implicated in the pathogenesis of various cancer types, however its role in ESCC is unknown.

Materials and Methods: Data from the public database was analyzed to address the expression of LRG1 in ESCC. Gain-of-function studies were performed in select ESCC cell lines by over-expression or addition of recombinant LRG1, while loss-of-function studies achieved by small interfering RNA mediated knockdown. Wound healing and transwell assays were conducted to investigate ESCC cell migration and invasion upon manipulating LRG1 levels. Western blot and Immunofluorescence staining were used to examine the changes in epithelial to mesenchymal transition (EMT) and TGFβ signaling pathway.

Results: LRG1 mRNA levels were found to be significantly down-regulated in patients with ESCC as well as in several ESCC cell lines. Silencing of LRG1 promoted, while overexpression of LRG1 inhibited ESCC cell migration and invasion. In line with this, Silencing of LRG1 enhanced, while overexpression of LRG1 reduced TGFβ signaling and EMT of ESCC cells.

Conclusion/Significance: LRG1 suppresses ESCC cell migration and invasion via negative modulation of TGFβ signaling and EMT. Down-regulation of LRG1 in ESCC patients may favor tumor metastasis and disease progression.