Chitinase 3-like 1 secreted from cancer-associated fibroblasts promotes tumor angiogenesis via interleukin-8 secretion in colorectal cancer.

The cancer­stromal interaction has been demonstrated to promote tumor progression, and cancer-associated fibroblasts (CAFs), which are the main components of stromal cells, have attracted attention as novel treatment targets. Chitinase 3-like 1 (CHI3L1) is a chitinase-like protein, which affects cell proliferation and angiogenesis. However, the mechanisms through which cells secrete CHI3L1 and through which CHI3L1 mediates tumor progression in the cancer microenvironment are still unclear. Accordingly, the present study assessed the secretion of CHI3L1 in the microenvironment of colorectal cancer and evaluated how CHI3L1 affects tumor angiogenesis. CAFs and normal fibroblasts (NFs) established from colorectal cancer tissue, and human colon cancer cell lines were evaluated using immunostaining, cytokine antibody array, RNA interference, reverse transcription-quantitative PCR (RT-qPCR), ELISA, western blotting and angiogenesis assays. The expression and secretion of CHI3L1 in CAFs were stronger than those in NFs and colorectal cancer cell lines. In addition, interleukin-13 receptor α2 (IL-13Rα2), a receptor for CHI3L1, was not expressed in colorectal cancer cell lines, but was expressed in fibroblasts, particularly CAFs. Furthermore, the expression and secretion of IL-8 in CAFs was stronger than that in NFs and cancer cell lines, and recombinant CHI3L1 addition increased IL-8 expression in CAFs, whereas knockdown of CHI3L1 suppressed IL-8 expression. Furthermore, IL-13Rα2 knockdown suppressed the enhancement of IL-8 expression induced by CHI3L1 treatment in CAFs. For vascular endothelial growth factor-A (VEGFA), similar results to IL-8 were observed in an ELISA for comparison of secretion between CAFs and NFs and for changes in secretion after CHI3L1 treatment in CAFs; however, no significant differences were observed for changes in expression after CHI3L1 treatment or IL-13Rα2 knockdown in CAFs assessed using RT-qPCR assays. Angiogenesis assays revealed that tube formation in vascular endothelial cells was suppressed by conditioned medium from CAFs with the addition of human CHI3L1 neutralizing antibodies compared with control IgG, and also suppressed by conditioned medium from CAFs transfected with CHI3L1, IL-8 or VEGFA small interfering RNA compared with negative control small interfering RNA. Overall, the present findings indicated that CHI3L1 secreted from CAFs acted on CAFs to increase the secretion of IL-8, thereby affecting tumor angiogenesis in colorectal cancer.

YKL-40 protein expression in human tumor samples and human tumor cell line xenografts: implications for its use in tumor models.

BACKGROUND: YKL-40, also known as non-enzymatic chitinase-3 like-protein-1 (CHI3L1), is a glycoprotein expressed and secreted mainly by inflammatory cells and tumor cells. Accordingly, several studies demonstrated elevated YKL-40 serum levels in cancer patients and found YKL-40 to be correlated with a poor prognosis and disease severity in some tumor entities. YKL-40 was suggested to be involved in angiogenesis and extracellular matrix remodeling. As yet, however, its precise biological function remains elusive. METHODS: As YKL-40 protein expression has only been investigated in few malignancies, we employed immunohistochemical detection in a large multi-tumor tissue microarray consisting of 2,310 samples from 72 different tumor entities. In addition, YKL-40 protein expression was determined in primary mouse xenograft tumors derived from human cancer cell lines. RESULTS: YKL-40 could be detected in almost all cancer entities and was differently expressed depending on tumor stage and subtype (e.g., thyroid cancer, colorectal cancer, gastric cancer and ovarian cancer). While YKL-40 was absent in in vitro grown human cancer cell lines, YKL-40 expression was upregulated in xenograft tumor tissues in vivo. CONCLUSIONS: These data provide new insights into YKL-40 expression at the protein level in various tumor entities and its regulation in tumor models. Our data suggest that upregulation of YKL-40 expression is a common feature in vivo and is finely regulated by tumor cell-microenvironment interactions.

Chitinase-3 like-protein-1 function and its role in diseases.

Non-enzymatic chitinase-3 like-protein-1 (CHI3L1) belongs to glycoside hydrolase family 18. It binds to chitin, heparin, and hyaluronic acid, and is regulated by extracellular matrix changes, cytokines, growth factors, drugs, and stress. CHI3L1 is synthesized and secreted by a multitude of cells including macrophages, neutrophils, synoviocytes, chondrocytes, fibroblast-like cells, smooth muscle cells, and tumor cells. It plays a major role in tissue injury, inflammation, tissue repair, and remodeling responses. CHI3L1 has been strongly associated with diseases including asthma, arthritis, sepsis, diabetes, liver fibrosis, and coronary artery disease. Moreover, following its initial identification in the culture supernatant of the MG63 osteosarcoma cell line, CHI3L1 has been shown to be overexpressed in a wealth of both human cancers and animal tumor models. To date, interleukin-13 receptor subunit alpha-2, transmembrane protein 219, galectin-3, chemo-attractant receptor-homologous 2, and CD44 have been identified as CHI3L1 receptors. CHI3L1 signaling plays a critical role in cancer cell growth, proliferation, invasion, metastasis, angiogenesis, activation of tumor-associated macrophages, and Th2 polarization of CD4+ T cells. Interestingly, CHI3L1-based targeted therapy has been increasingly applied to the treatment of tumors including glioma and colon cancer as well as rheumatoid arthritis. This review summarizes the potential roles and mechanisms of CHI3L1 in oncogenesis and disease pathogenesis, then posits investigational strategies for targeted therapies.

Helicobacter Pylori Induces GATA3-Dependent Chitinase 3 Like 1 (CHI3L1) Upregulation and Contributes to Vascular Endothelial Injuries.

BACKGROUND Helicobacter pylori infection is associated with various vascular diseases. However, its mechanism is yet to be defined. The present study aimed to investigate the effect of H. pylori on vascular endothelial cells as well as the GATA3-related mechanism of H. pylori infection-induced endothelial injuries. MATERIAL AND METHODS A co-culture of H. pylori with human umbilical endothelial cells (HUVECs) was produced. The proliferation of HUVECs that had been incubated with H. pylori were examined via CCK-8 (Cell Counting Kit-8) and EdU (5-ethynyl-2'-deoxyuridine) staining. Cell migration and microtubules formation were studied using Transwell and tube formation respectively. Construction of a mouse model of H. pylori infection as well as the expression of GATA3 and CHI3L1 in vessels were tested using western blot and immunohistochemistry. Small interfering RNA (siRNA) of GATA3 were transfected into HUVECs in order to establish cell lines with knocked-down GATA3. The production of the aforementioned molecules and p38 mitogen-activated protein kinase (MAPK) related molecules in HUVECs was measured using quantitative real-time polymerase chain reaction and western blot. RESULTS H. pylori significantly inhibited the proliferation, migration, and tube formation of HUVECs, as well as increased the production of the inflammatory factor CHI3L1 and phosphorylated p38 from endothelial cells along with an increased expression of GATA3. Elevated levels of the GATA3 and CHI3L1 were also found in the arteries of H. pylori-infected mice. Following GATA3 knockdown, the H. pylori-induced dysfunction of HUVECs was restored. CONCLUSIONS H. pylori impaired vascular endothelial function. This might be due to the H. pylori-induced increased expression of GATA3, as well as the GATA3 mediated upregulated CHI3L1 and activation of the p38 MAPK pathway.

Sex difference in CHI3L1 expression levels in human brain aging and in Alzheimer's disease.

Several genetic sexual dimorphisms have been identified in animal and human brains, which may form a neural basis for sex-specific predisposition to neurological diseases. In the last years, clinical studies have observed that Alzheimer's disease (AD) disproportionately affects women compared with men. Chitinase-3-Like 1 protein (CHI3L1) has been frequently investigated in body fluids as a surrogate marker of neuroinflammation in AD and other neurological disorders. Nevertheless, the sex-related differences in CHI3L1 expression in the human brain has not yet been investigated. Here we aimed to evaluate the specificity of increase of CHI3L1 in five brain regions (cerebellum, dorsolateral prefrontal cortex, prefrontal cortex, hippocampus, and visual cortex) of male and female controls during normal aging, as well as in AD patients. We selected ten microarray datasets from NCBI, representing normal aging (n = 1290) and AD (n = 992), and stratified the brain specimens according to age, gender and brain region. The expression levels of CHI3L1 were correlated with age and gender. Female control brain specimens showed higher CHI3L1 expression than male brains. The expression differences between men and women were most obvious in older subjects. The expression analysis of CHI3L1 in the different brain regions of AD subjects also showed sex differences; females with AD had greater expression in the cerebellum than males. Notably, sex-associated CHI3L1 expression differences in hippocampus disappeared in AD. These findings demonstrate that the expression of CHI3L1 in the brains of cognitively unimpaired subjects and AD patients is closely linked to age and sex, which was most obvious in the cerebellum. Further studies are needed to confirm our results.

Astrocytes induce proliferation of oligodendrocyte progenitor cells via connexin 47-mediated activation of Chi3l1 expression.

OBJECTIVE: Demyelinating neurodegenerative diseases are some of the most important neurological diseases that threaten the health of the elderly. Astrocytes (ASTs) play an important role in the regulation of the growth and development of oligodendrocytes (OLs) and oligodendrocyte progenitor cells (OPCs), which participate in remyelination. This study investigated the mechanism by which ASTs promote the proliferation of OPCs via connexin 47 (Cx47) in OPCs. MATERIALS AND METHODS: Under direct-contact co-culture conditions, we performed Cx47 siRNA interference in ASTs and OPCs and tested the cell proliferation ability by flow cytometry and with 5-ethynyl-20-deoxyuridine (EdU). We then detected Chi3l1 expression by Western blotting and immunofluorescence. Next, after the addition of exogenous Chi3l1 protein to OPCs under monoculture conditions, we tested the cell proliferation ability by flow cytometry and EdU. RESULTS: After siRNA interference with Cx47, the expression of Chi3l1 decreased from 1.10±0.91 to 0.30±0.08, and the proportion of new OPCs decreased from 48.7±3.8% to 28.4±6.6%. Moreover, upon addition of exogenous Chi3l1 protein under OPCs mono-culture conditions, the expression of cyclin D1 increased from 0.68±0.09 to 1.16±0.14, leading to an increased number of OPCs in the S phase, from 7.37±1.38% to 13.55±1.60%. CONCLUSIONS: Cx47/Chi3l1 plays an important role in the promotion of OPCs proliferation by ASTs. ASTs can promote the expression of Chi3l1 via Cx47 in OPCs, and then activate the expression of cyclin D1 and regulate the cell cycle of OPCs, thereby promoting cell proliferation. This study provides a new target for the treatment of neurodegenerative diseases.

High expression of Chitinase 3-like-1 is an unfavorable prognostic factor in urothelial carcinoma of upper urinary tract and urinary bladder.

BACKGROUND: Metabolic adaptation in cancer cells is important for cancer cell survival. Alternation in cellular metabolism getting more energy to support cell proliferation played a critical role in disease progression. We initially analyzed the public transcriptome of urothelial carcinoma in Gene Expression Omnibus database (GSE31684) with particular focus on genes associated with carbohydrate metabolism, and found that Chitinase 3-like-1 (CHI3L1) was a significantly up-regulated gene associated with advanced disease status. This study was aimed to evaluate the expression and prognostic significance of CHI3L1 in upper urinary tract urothelial carcinoma (UTUC) and urinary bladder urothelial carcinoma (UBUC). MATERIALS AND METHODS: We performed immunohistochemical study to evaluate CHI3L1 expression in 2 well-defined cohorts of urothelial carcinoma, including UTUC (n = 340) and UBUC (n = 295). CHI3L1 expression level was determined by H-score method. The associations between CHI3L1 expression and clinicopathological features, disease-specific survival (DSS) and metastasis-free survival (MFS) were analyzed. RESULTS: High expression of CHI3L1 was significantly associated with adverse clinicopathological features in UTUC or UBUC, including advanced tumor status (pT), nodal metastasis, high histological grade, vascular invasion, perineural invasion, and high mitotic activity (all P < 0.05). Kaplan-Meier survival analysis revealed that patients with high CHI3L1 expression had shorter DSS and MFS in both UTUC and UBUC (all P < 0.05). In multivariate survival analyses, high expression of CHI3L1 acted as an independent prognostic factor for worse DSS (P < 0.001 in UTUC and P = 0.036 in UBUC) and MFS (P = 0.002 in UTUC and P = 0.003 in UBUC) in both UTUC and UBUC groups. CONCLUSIONS: High expression of CHI3L1 was significantly associated with aggressive clinicopathological features and acted as an independent prognostic factor for worse outcome in urothelial carcinoma.

YKL-40 expression in pterygium: a potential role in the pathogenesis.

PURPOSE: The aim of the study was to evaluate whether YKL-40 (chitinase 3-like 1 protein) plays a role in pterygium pathogenesis. METHODS: We included 42 primary pterygium patients and 24 control subjects with normal bulbar conjunctiva in the study. The pterygium patients were classified into the atrophic, fleshy, and intermediate groups according to the Tan classification. We then surgically removed the primary nasal pterygium and normal bulbar conjunctiva from the patients and immunohistochemically investigated YKL-40 expression. RESULTS: YKL-40 expression was statistically significantly higher in the epithelial, endothelial, and stromal cells of the pterygium tissues than in the control tissues (P = 0.009, P = 0.003, P = 0.002, respectively). There was no significant correlation between the pterygium subgroups and YKL-40 expression (P > 0.05). CONCLUSIONS: We believe YKL-40 may play a significant role in pterygium pathogenesis.

Caffeic acid and ellagic acid ameliorate adjuvant-induced arthritis in rats via targeting inflammatory signals, chitinase-3-like protein-1 and angiogenesis.

Rheumatoid arthritis (RA) is a chronic inflammatory arthropathy that principally attacks the joints. The present study aimed to explore the potential anti-arthritic effects of caffeic acid and ellagic acid in adjuvant-induced arthritis, compared to celecoxib. The current study also explored the underlying molecular mechanisms e.g., pro-inflammatory signals including chitinase-3-like protein-1 (CHI3L1); a glycoprotein that correlates with RA joint destruction besides angiogenesis, oxidative stres and apoptosis. Interestingly, caffeic and ellagic acids attenuated the severity of arthritis with comparable efficacy to celecoxib. Both agents effectively mitigated paw edema and inflammatory cell infiltration and protected the joint tissues against pannus formation along with cartilage and bone destruction. Notably, they also lowered the paw expression of NF-κB and the downstream effector CHI3L1 and its synthesis inducer IL-1ß. They also lowered the levels of the tissue remodeling factor MMP-9 and the angiogenic signal VEGF in rat paws. Both agents also suppressed serum oxidative stress via diminishing lipid peroxides and nitric oxide together with augmentation of reduced glutathione in arthritic animals. Regarding apoptosis, they attenuated paw caspase-3 levels, favoring cell survival. Together, these favorable findings may advocate the use of caffeic and ellagic acids as adjunct modalities for the management of RA to mitigate joint damage.

Chitinase-3-like Protein 1 (YKL-40) Expression in Squamous Cell Skin Cancer.

BACKGROUND/AIM: YKL-40 plays a role in proliferation and differentiation of malignant cells. The aim of this study was to examine whether YKL-40 is expressed in cutaneous squamous cell carcinoma (SCC). MATERIALS AND METHODS: The study was based on histologically-confirmed biopsies of cutaneous SCCs obtained from 38 patients. The tissue expression of YKL-40 was assessed using an immunohisto-chemical method. The percentage of cells showing a positive reaction as well as the intensity of the IHC reaction was assessed using the immunoreactive score developed by Remmele and Stegner. RESULTS: All samples of cutaneous SCCs showed cytoplasmic expression of YKL-40. The intensity of YKL-40 expression varied between 1 and 8 points, according to the applied scale. In the majority of cancers about 10-80% of tumor cells were positive for YKL-40. The intensity of the reaction was low (20 samples, 52.6%) or medium (18 samples, 47.4%). CONCLUSION: YKL-40 is expressed in cutaneous SCC. Further research is needed to establish the value of YKL-40 for diagnosis and monitoring of SCC.

The Role of CHI3L1 Expression in Angiogenesis in Invasive Ductal Breast Carcinoma.

BACKGROUND/AIM: An increased level of chitinase 3 like 1 protein (CHI3L1) expression is observed in patients with cancer and may have potential prognostic value. The aim of this study was to evaluate the role of CHI3L1 in angiogenesis in invasive ductal breast carcinoma (IDC) (n=110). MATERIALS AND METHODS: Immunohistochemistry was used to assess the expression of CHI3L1, CD31, CD34, vascular endothelial growth factor (VEGFA, VEGFC and VEGFD). Real-time polymerase chain reaction and western blot were used to determine the level of CHI3L1 mRNA and protein. RESULTS: Immunohistochemistry demonstrated positive correlation between CHI3L1 expression and angiogenesis markers: CD31 (r=0.34, p=0.0003), CD34 (r=0.24, p=0.012), VEGFD (r=0.24, p=0.013). Higher CHI3L1 expression in estrogen receptor-negative (p=0.041) and progesterone receptor-negative (p=0.014) cancer was observed. Higher CHI3L1 expression was reported in cancer tissues in comparison to non-malignant breast lesions. CONCLUSION: These results suggest a potential role of CHI3L1 in angiogenesis in IDC and may suggest its involvement in cancer progression.

Differences in expression of YKL-40 and TLR4 in nasal sinus mucosa of chronic sinusitis patients with and without nasal polyps.

This work studies the expression differences of YKL-40 and TLR4 in nasal sinus mucosa of chronic sinusitis patients with and without nasal polyps and its clinical significances. Fifty chronic sinusitis patients with nasal polyps and 50 chronic sinusitis patients without, accepted by our hospital during February 2016-February 2017, were included and taken as group A and group B, respectively. In addition, another 50 patients with nasal deviation were taken as group C (control group). The ostiomeatal complex mucosa of group A and B and the inferior turbinate mucosa of group C were taken and the fluorescence quantitative PCR method was applied to detect the expression of YKL-40, TLR4 and NF- κB of the mucosa and explore and influence of YKL-40 and TLR4 on NF-κB. There was a negative correlation between YKL-40 and TLR4 in group A, and the difference was statistically significant (P less than 0.05) while there was no relationship between YKL-40 and TLR4 expression in group B. The level of YKL-40 protein in group A was higher than that in group B, which was statistically significant (P less than 0.05). YKL-40 and TLR4 were positively correlated in group A while there was no correlation between YKL- 40 and TLR4 expression in group B. The expression of YKL-40, TLR4 and NF-κB in chronic sinusitis patients with nasal polyps was high. In addition, there was a negative correlation between YKL-40 and TLR4 expression in chronic sinusitis patients with nasal polyps. YKL-40 and TLR4 interacted with each other to activate NF-κB and promote disease progression.

Hypothesis: Is there a link between the immune response to Human Herpes Virus type 6Α (HHV-6Α) infection and the interaction network (interactome) of the genes encoding the CTSS, PTX3, CHI3L1, Mx1, CXCL16, BIRC3 and BST2 proteins?

Human Herpes Virus type 6 (HHV-6) is a ubiquitous virus consisting of two viral species, HHV-6A and HHV-6B that have been associated with numerous and diverse pathologies. As many other viruses HHV-6 modulates the apoptotic machinery of its host to subvert immune response to infection, yet the exact mechanisms behind this process remain under investigation. The genes encoding the CTSS, PTX3, CHI3L1, Mx1, CXCL16, BIRC3 and BST2 proteins have been linked to HHV-6Α related neurologic diseases whilst also associated with apoptosis. This study aimed at the identification and functional analysis of the gene interaction network (interactome) of CTSS-PTX3-CHI3L1-Mx1-CXCL16-BIRC3-BST2 so as to evaluate the hypothesis of a probable link between the latter and host's immune response to HHV-6A infection.

Angiogenic potential of YKL-40 in the dynamics of tumor niche.

A multitude of clinical studies showed the elevation of YKL-40 in subjects with different kinds of tumors. It is predicted that an inherent correlation exists between survivals of cancer patients with total YKL-40 serum levels, making this factor as a potential novel biomarker. However, the crucial role of YKL-40 in the dynamics of cancers, especially angiogenesis, has not yet been completely addressed. In this review, we highlighted the various facets of YKL-40 and its importance in cancer biology as a bio-shuttle in gene therapy.

YKL-40 in the brain and cerebrospinal fluid of neurodegenerative dementias.

BACKGROUND: YKL-40 (also known as Chitinase 3-like 1) is a glycoprotein produced by inflammatory, cancer and stem cells. Its physiological role is not completely understood but YKL-40 is elevated in the brain and cerebrospinal fluid (CSF) in several neurological and neurodegenerative diseases associated with inflammatory processes. Yet the precise characterization of YKL-40 in dementia cases is missing. METHODS: In the present study, we comparatively analysed YKL-40 levels in the brain and CSF samples from neurodegenerative dementias of different aetiologies characterized by the presence of cortical pathology and disease-specific neuroinflammatory signatures. RESULTS: YKL-40 was normally expressed in fibrillar astrocytes in the white matter. Additionally YKL-40 was highly and widely expressed in reactive protoplasmic cortical and perivascular astrocytes, and fibrillar astrocytes in sporadic Creutzfeldt-Jakob disease (sCJD). Elevated YKL-40 levels were also detected in Alzheimer's disease (AD) but not in dementia with Lewy bodies (DLB). In AD, YKL-40-positive astrocytes were commonly found in clusters, often around ß-amyloid plaques, and surrounding vessels with ß-amyloid angiopathy; they were also distributed randomly in the cerebral cortex and white matter. YKL-40 overexpression appeared as a pre-clinical event as demonstrated in experimental models of prion diseases and AD pathology. CSF YKL-40 levels were measured in a cohort of 288 individuals, including neurological controls (NC) and patients diagnosed with different types of dementia. Compared to NC, increased YKL-40 levels were detected in sCJD (p < 0.001, AUC = 0.92) and AD (p < 0.001, AUC = 0.77) but not in vascular dementia (VaD) (p > 0.05, AUC = 0.71) or in DLB/Parkinson's disease dementia (PDD) (p > 0.05, AUC = 0.70). Further, two independent patient cohorts were used to validate the increased CSF YKL-40 levels in sCJD. Additionally, increased YKL-40 levels were found in genetic prion diseases associated with the PRNP-D178N (Fatal Familial Insomnia) and PRNP-E200K mutations. CONCLUSIONS: Our results unequivocally demonstrate that in neurodegenerative dementias, YKL-40 is a disease-specific marker of neuroinflammation showing its highest levels in prion diseases. Therefore, YKL-40 quantification might have a potential for application in the evaluation of therapeutic intervention in dementias with a neuroinflammatory component.

CHI3L1 and CHI3L2 overexpression in motor cortex and spinal cord of sALS patients.

BACKGROUND: Amyotrophic Lateral Sclerosis (ALS) is a rapidly progressive neurodegenerative disease characterized by the degeneration and death of upper (UMN) and lower (LMN) motor neurons. In the last decade, it has been shown that Chitinases are an important prognostic indicator of neuro-inflammatory damage induced by microglia and astrocytes. MATERIALS AND METHODS: We analyzed microarray datasets obtained from the Array Express in order to verify the expression levels of CHI3L1 and CHI3L2 in motor cortex biopsies of sALS patients with different survival times. We also divided the sALS patients into smokers and non-smokers. In order to extend our analysis, we explored two additional microarray datasets, GSE833 and GSE26927, of post-mortem spinal cord biopsies from sALS patients. RESULTS: The analysis showed that CHI3L1 and CHI3L2 expression levels were significantly upregulated in the motor cortex of sALS patients, compared to the healthy controls. Moreover, their expression levels were negatively correlated with survival time. Interesting results were obtained when we compared the expression levels of Chitinases among smokers. We showed that CHI3L1 and CHI3L2 were significantly upregulated in sALS smokers compared to non-smokers. Furthermore, we found that four genes belonging to the Chitinases network (SERPINA3, C1s, RRAD, HLA-DQA1) were significantly upregulated in the motor cortex of sALS patients and positively correlated with Chitinases expression levels. Similar results were obtained during the exploration of the two-microarray dataset. CONCLUSIONS: This study suggests that CHI3L1 and CHI3L2 are associated with the progression of neurodegeneration in motor cortex and spinal cord of sALS patients.

YKL-40 (Chitinase 3-like I) is expressed in a subset of astrocytes in Alzheimer's disease and other tauopathies.

BACKGROUND: The innate immune system is known to be involved early in the pathogenesis of Alzheimer's disease (AD) and other neurodegenerative disorders. The inflammatory response in the central nervous system can be measured postmortem or through a series of inflammatory mediator surrogates. YKL-40 (also named Chitinase-3-like I) has been frequently investigated in body fluids as a surrogate marker of neuroinflammation in AD and other neurological disorders. However, the expression pattern of YKL-40 in the human brain with neurodegenerative pathology remains poorly investigated. Our aim was to study the cellular expression pattern of YKL-40 in the brain of patients with clinical and neuropathological criteria for AD (n = 11); three non-AD tauopathies: Pick's disease (PiD; n = 8), corticobasal degeneration (CBD; n = 8) and progressive supranuclear palsy (PSP; n = 9) and a group of neurologically healthy controls (n = 6). METHODS: Semiquantitative neuropathological evaluation and quantitative confocal triple immunofluorescence studies were performed. An in-house algorithm was used to detect and quantify pathology burden of random regions of interest on a full tissue-section scan. Kruskal-Wallis and Dunn's multiple comparison tests were performed for colocalization and quantification analyses. RESULTS: We found that brain YKL-40 immunoreactivity was observed in a subset of astrocytes in all four diseases and in controls. There was a strong colocalization between YKL-40 and the astroglial marker GFAP but not with neuronal nor microglial markers. Intriguingly, YKL-40-positive astrocytes were tau-negative in PSP, CBD and PiD. The number of YKL-40-positive astrocytes was increased in tauopathies compared with that in controls. A positive correlation was found between YKL-40 and tau immunoreactivities. CONCLUSIONS: This study confirms that YKL-40 is expressed by a subset of astrocytes in AD and other tauopathies. YKL-40 expression is elevated in several neurodegenerative conditions and correlates with tau pathology.

Overexpression of YKL-40 Predicts Poor Prognosis in Patients Undergoing Curative Resection of Pancreatic Cancer.

OBJECTIVES: The aim of this study was to determine the prognostic value of YKL-40 expression in patients undergoing curative resection of pancreatic cancer. METHODS: This cohort study included 234 consecutive patients with pancreatic ductal adenocarcinoma who underwent curative resection. Surgical specimens were immunohistochemically assessed for YKL-40 expression. Kaplan-Meier method and Cox regression were used to evaluate the prognostic impact of YKL-40 expression. A multivariate logistic regression model was performed to examine the correlation between YKL-40 expression and tumor stage. RESULTS: Of the 234 patients, YKL-40 overexpression was detected in 149 (63.7%) patients. Survival curves showed that patients with YKL-40 overexpression had significantly shorter survival time than those with low YKL-40 expression (P < 0.001). Cox regression analysis indicated that YKL-40 expression was an independent prognostic factor for both overall survival (hazard ratio, 3.82; 95% confidence interval [CI], 2.38-6.13) and progression-free survival (hazard ratio, 3.73; 95% CI, 2.33-5.99). Multivariate logistic regression analysis demonstrated that YKL-40 overexpression was an independent predictor for advanced tumor stage (odds ratio 4.15; 95% CI, 1.35-12.71). CONCLUSIONS: YKL-40 overexpression predicts poor prognosis and advanced tumor stage in patients undergoing curative resection of pancreatic cancer. Application of adjuvant treatment targeting the YKL-40 pathway may improve prognosis.

Elevated YKL-40 expression is associated with a poor prognosis in breast cancer patients.

Numerous studies have investigated the prognostic role of YKL-40 in breast cancer, but yielded inconsistent results. To derive a more precise evaluation, relevant publications assessing the association between YKL-40 expression and clinical outcome of breast cancer patients were electronically searched and identified. A combined analysis of included studies was performed using fixed- or random-effect model to calculate the pooled hazard ratio (HR) or odds ratio(OR) and 95% confidence interval (95%CI) for the assessment of the association. Ten eligible studies involving 1250 patients were ultimately included in the meta-analysis. Overall, the pooled analysis showed that elevated YKL-40 expression was significantly associated with a poor overall survival(OS: HR=1.48, 95%CI= 1.11-1.97) and disease-free survival(DFS: HR=1.51, 95%CI= 1.10-2.07). The subgroup analysis by detection methods revealed an unfavorable OS in breast cancer patients with elevated YKL-40 expression evaluated by IHC(HR=1.39, 95%CI=1.12-1.71) but not by ELISA/RIA. Also, the stratification analysis by ethnicity showed a significant association between increased YKL-40 expression and shorter OS of breast cancer patients in western population(HR=1.51, 95%CI=1.03-2.21) as well as Asian population (HR=1.40, 95%CI= 1.05-1.86). Similarly, the subgroup analysis by detection methods revealed a significantly inferior DFS in breast cancer patients with increased YKL-40 expression disregarding the use of IHC(HR=2.02, 95%CI=1.47-2.79) or ELISA/RIA(HR=1.06, 95%CI= 1.02 -1.10). Additionally, increased YKL-40 expression was found to significantly correlate with larger tumor size (OR=2.38, 95%CI=1.41-4.05).The present meta-analysis indicate that elevated YKL-40 expression is associated with a poor prognosis in breast cancer patients. YKL-40 may serve as a promising predictive biomarker of prognosis of breast cancer.

PPIC, EMP3 and CHI3L1 Are Novel Prognostic Markers for High Grade Glioma.

Current treatment methods for patients diagnosed with gliomas have shown limited success. This is partly due to the lack of prognostic genes available to accurately predict disease outcomes. The aim of this study was to investigate novel prognostic genes based on the molecular profile of tumor samples and their correlation with clinical parameters. In the current study, microarray data (GSE4412 and GSE7696) downloaded from Gene Expression Omnibus were used to identify differentially expressed prognostic genes (DEPGs) by significant analysis of microarray (SAM) between long-term survivors (>2 years) and short-term survivors (≤2 years). DEPGs generated from these two datasets were intersected to obtain a list of common DEPGs. The expression of a subset of common DEPGs was then independently validated by real-time reverse transcription quantitative PCR (qPCR). Survival value of the common DEPGs was validated using known survival data from the GSE4412 and TCGA dataset. After intersecting DEPGs generated from the above two datasets, three genes were identified which may potentially be used to determine glioma patient prognosis. Independent validation with glioma patients tissue (n = 70) and normal brain tissue (n = 19) found PPIC, EMP3 and CHI3L1 were up-regulated in glioma tissue. Survival value validation showed that the three genes correlated with patient survival by Kaplan-Meir analysis, including grades, age and therapy.