Aberrant methylation of the SPARC gene promoter and its clinical implication in gastric cancer

Circulating NPTX2 methylation as a non-invasive biomarker for prognosis and monitoring of metastatic pancreatic cancer

BACKGROUND

Pancreatic cancer is the most lethal cancer with a dismal prognosis mainly due to diagnosis at advanced stage and ineffective treatments. CA19-9 levels and computed tomography (CT) imaging are the main standard criteria for evaluating disease progression and treatment response. In this study we explored liquid biopsy-based epigenetic biomarkers for prognosis and monitoring disease in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC).

METHODS

Plasma samples were collected from 44 mPDAC patients at the time of diagnosis, and in 15 of them, additional samples were obtained during follow-up of the disease. After cell-free DNA (cfDNA), isolation circulating levels of methylated NPTX2, SPARC, BMP3, SFRP1 and TFPI2 genes were measured using digital droplet PCR (ddPCR). BEAMing technique was performed for quantitation of RAS mutations in cfDNA, and CA19-9 was measured using standard techniques.

RESULTS

NPTX2 was the most highly and frequently methylated gene in cfDNA samples from mPDAC patients. Higher circulating NPTX2 methylation levels at diagnosis were associated with poor prognosis and efficiently stratified patients for prediction of overall survival (6.06% cut-off, p = 0.0067). Dynamics of circulating NPTX2 methylation levels correlated with disease progression and response to therapy and predicted better than CA19-9 the evolution of disease in mPDAC patients. Remarkably, in many cases the disease progression detected by CT scan was anticipated by an increase in circulating NPTX2 methylation levels.

CONCLUSIONS

Our study supports circulating NPTX2 methylation levels as a promising liquid biopsy-based clinical tool for non-invasive prognosis, monitoring disease evolution and response to treatment in mPDAC patients.

Clinicopathological and prognostic significance of SPARC expression in gastric cancer: A meta‑analysis and bioinformatics analysis

Secreted protein acidic and rich in cysteine (SPARC) is a member of the extracellular matrix glycoprotein family that binds to calcium ions. It may bind to a variety of proteins in the extracellular matrix and also compete with cell membrane surface receptors for growth. In the present study, the relationship between SPARC expression in gastric cancer tissues and the clinicopathological characteristics and prognosis of patients with gastric cancer were systematically evaluated. A meta-analysis and bioinformatics analysis were performed using the PubMed, Chinese National Knowledge Infrastructure, Kaplan-Meier (KM)-plotter, The Cancer Genome Atlas (TCGA), Gene Expression Profiling Interactive Analysis (GEPIA), University of ALabama at Birmingham CANcer (UALCAN), Human Protein Atlas (HPA) and Timer databases. SPARC was mainly expressed in tumor mesenchymal cells. The meta-analysis indicated that SPARC expression was higher in gastric cancer tissues than in normal tissues. SPARC was associated with the degree of differentiation and distant metastasis. K-M plotter results indicated that high SPARC expression was negatively associated with overall survival, post-progression survival and progression-free survival rates of patients. According to the Oncomine, GEPIA, UALCAN and HPA databases, SPARC mRNA and protein expression was upregulated in gastric cancer vs. normal tissues and was negatively associated with poor patient prognosis. In the TCGA database, univariate analysis indicated that lymph node metastasis and distant metastasis were associated with the prognosis of patients with gastric cancer. Cox multifactorial analysis suggested that high SPARC expression, age and distant metastasis were important factors affecting the survival time of patients with gastric cancer. Analysis with the Timer database indicated that SPARC was closely associated with the proportion of 7 immune-cell infiltrates in gastric cancer. These findings indicated that high expression of SPARC may be a potential marker of tumorigenesis and metastasis in patients with gastric cancer.

Enhancing clinical potential of liquid biopsy through a multi-omic approach: A systematic review

In the last years, liquid biopsy gained increasing clinical relevance for detecting and monitoring several cancer types, being minimally invasive, highly informative and replicable over time. This revolutionary approach can be complementary and may, in the future, replace tissue biopsy, which is still considered the gold standard for cancer diagnosis. “Classical” tissue biopsy is invasive, often cannot provide sufficient bioptic material for advanced screening, and can provide isolated information about disease evolution and heterogeneity. Recent literature highlighted how liquid biopsy is informative of proteomic, genomic, epigenetic, and metabolic alterations. These biomarkers can be detected and investigated using single-omic and, recently, in combination through multi-omic approaches. This review will provide an overview of the most suitable techniques to thoroughly characterize tumor biomarkers and their potential clinical applications, highlighting the importance of an integrated multi-omic, multi-analyte approach. Personalized medical investigations will soon allow patients to receive predictable prognostic evaluations, early disease diagnosis, and subsequent ad hoc treatments.

The Matricellular Protein SPARC Decreases in the Lacrimal Gland At Adulthood and During Inflammation

Purpose

Secreted protein acidic and rich in cysteine (SPARC) is a matricellular glycoprotein abundantly expressed in basement membranes and capsules surrounding a variety of organs and tissues. It mediates extracellular matrix organization and has been implicated in cell contraction. Here, we evaluated the expression of SPARC in the murine lacrimal gland at adulthood and during inflammation.

Methods

Lacrimal glands of young mice (4-6 weeks old) and adult mice (32-40 weeks old) were used for extraction of DNA, RNA, and protein. The presence of SPARC was assessed by quantitative PCR, ELISA, and immunofluorescence microscopy. 5-Methylcytosine and DNA methylation were evaluated using ELISA and bisulfite genomic sequencing, respectively. The effects of cytokines and inflammation in Sparc expression were evaluated in vitro and in the non-obese diabetic (NOD) mouse model of Sjögren's syndrome.

Results

The mRNA and protein levels of SPARC were downregulated in lacrimal glands of mature adult mice presenting age-related histological alterations such as increased deposition of lipofuscin and lipids. Epigenetic analyses indicated that glands in adult mice contain higher levels of global DNA methylation and show increased hypermethylation of specific CpG sites within the Sparc gene promoter. Analysis of smooth muscle actin (SMA)-green fluorescent protein (GFP) transgenic mice revealed that SPARC localizes primarily to myoepithelial cells within the gland. Treatment of myoepithelial cells with IL-1β or TNF-α and the development of inflammation in the NOD mice led to decreased transcription of Sparc.

Conclusions

SPARC is a novel matricellular glycoprotein expressed by myoepithelial cells in the lacrimal gland. Loss of SPARC during adulthood and chronic inflammation might have detrimental consequences on myoepithelial cell contraction and the secretion of tear fluid.

Prognostic Significance of SPARC Expression in Breast Cancer: A Meta-Analysis and Bioinformatics Analysis

Secreted protein, acidic and rich in cysteine (SPARC, also known as osteonectin), is a small molecule glycoprotein associated with cell secretions. The purpose of our research is to clarify the clinicopathological and prognostic significance of SPARC expression in breast cancer. In this study, we performed a meta-analysis and bioinformatics analysis using the PubMed, Web of Science, Wanfang Data, and CNKI databases. The meta-analysis showed that SPARC expression was elevated in breast cancer tissue, compared with normal tissue, while SPARC expression in tumor stromal cells was higher than that of tumor cells. The expression of SPARC was positively correlated with histological grade and TNM staging. The Kaplan-Meier plotter showed that low SPARC expression was negatively correlated with the overall, postprogression, and distant metastasis survival rates of patients. According to Oncomine database, SPARC expression was upregulated in breast cancer than normal tissues. In TCGA database, univariate analysis showed that lymph node metastasis, distant metastasis, and TNM staging were negatively correlated with patient prognosis in breast cancers. Cox multivariate analysis showed that age, lymph node metastasis, distant metastasis, and TNM staging were important factors affecting the survival time of breast cancer patients. SPARC expression can be employed as a good indicator of prognosis of breast cancer patients, which will provide new methods and ideas of preventive treatment.

Expression of Cysteine-Rich Secreted Acidic Protein in Multiple Myeloma and Its Effect on the Biological Behavior of Cancer Cells

The multiple myeloma is a malignant clonal tumor of bone marrow plasma cells that is incurable and inevitably recurrent. The mechanisms of progression include tumor cell metastasis, immune escape, resistance to apoptosis, and malignant proliferation. The cysteine-rich secreted acidic protein is closely related to the growth, development, remodeling, and repair of cells and tissues. In our study, we divided myeloma patients and patients with other blood diseases into groups and measured the cysteine-rich secreted acidic protein (SPARC) content in the serum of different groups of patients as well as the prognostic differences. The U266 cells were transfected with interfering vectors and overexpressed SPARC vectors to determine the physiological functions of MM cells. Our results showed that SPARC was highly expressed in MM and the survival rate of the high SPARC expression group was lower than that of the low expression group. Interfering SPARC vectors inhibited cancer cell proliferation, migration, and invasion and promoted apoptosis. Overexpression of SPARC vectors promoted cancer cell development. SPARC affected the patient's disease development by regulating the biological behavior of the MM cells.

SPARC enhances 5-FU chemosensitivity in gastric cancer by modulating epithelial-mesenchymal transition and apoptosis

Previous studies have shown that secreted protein acidic and rich in cysteine (SPARC) proteins can inhibit the development of cancer cells in various ways, such as by inhibiting angiogenesis and inhibiting cell proliferation. In fact, SPARC proteins may have an effect on the chemoresistance of gastric cancer cells to 5-Fluorouracil (5-FU), which needs further research in the future. Therefore, the purpose of this study was to explore the relationship between SPARC proteins and the chemosensitivity of gastric cancer cells to 5-FU. In vitro, after SPARC protein levels were regulated by plasmid, siRNA and human recombinant SPARC protein transfection in MGC-803, SGC-7901 and BGC-823 cells, we detected epithelial-mesenchymal transition (EMT), apoptosis markers and cell viability after 5-FU treatment. In vivo, we implanted BGC-823 cells with stable SPARC overexpression into nude mice. Tumour size was measured to assess the effect of SPARC protein on tumour formation and 5-FU chemosensitivity. In SGC-7901 and BGC-823 cells, both endogenous and exogenous upregulation of SPARC protein levels decreased cell viability, destroyed cytoskeletal F-actin, inhibited cell migration, and downregulated a series of transcription factors to inhibit cell EMT; it also upregulated cell apoptosis-related proteins to promote cell apoptosis. However, we obtained opposite results in SPARC knockdown MGC-803 cells. In vivo, compared with the control group, the group engrafted with BGC-823 cells stably overexpressing SPARC had a significant smaller tumour size. After 5-FU treatment, the new tumour gradually decreased in size. Our results show that the SPARC protein could enhance 5-FU chemosensitivity in gastric cancer cell lines by inhibiting EMT and promoting cell apoptosis.

SPARC-p53: The double agents of cancer

Cancer is a complex disease with high incidence and mortality rates. The important role played by the tumor microenvironment in regulating oncogenesis, tumor growth, and metastasis is by now well accepted in the scientific community. SPARC is known to participate in tumor-stromal interactions and impact cancer growth in ambiguous ways, which either enhance or suppress cancer aggressiveness, in a context-dependent manner. p53 transcription factor, a well-established tumor suppressor, has been reported to promote tumor growth in certain situations, such as hypoxia, thus displaying a duality in its action. Although both proteins are being tested in clinical trials, the synergistic relation between them is yet to be explored in clinical practice. In this review, we address the controversial roles of SPARC and p53 as double agents in cancer, briefly summarizing the interaction found between these two molecules and its importance in cancer.

Potential Prognostic Role of SPARC Methylation in Non-Small-Cell Lung Cancer

The silencing of SPARC (secreted protein acid and rich in cysteine) gene through methylation of its promoter region represents a common event in many solid tumors and it is frequently associated with tumor progression and an aggressive clinical outcome. Anyhow, the data concerning the epigenetic mechanism of SPARC deregulation and its prognostic value in lung cancer are still incomplete. We explored the aberrant methylation of SPARC and its effects in 4 non-small cell lung cancer (NSCLC) cell lines and 59 NSCLC tissues and correlated the methylation levels with clinical-pathological features and disease outcome of patients. In 3 out of 4 tumor cell lines high SPARC methylation levels were observed. An inverse correlation between the epigenetic silencing and SPARC expression was confirmed by 5-Aza-2′-deoxycytidine ((5-Aza-CdR) treatment that also significantly induced a reduction in cell viability, proliferation and tumor cell migration. In tissues, the DNA methylation levels of the SPARC gene were significantly lower in paired non-neoplastic lungs (NLs) and normal lungs distant from tumor (NLDTs) than in NSCLCs (p = 0.002 and p = 0.0034 respectively). A promoter hypermethylation was detected in 68% of squamous cell carcinoma (SqCCs, 17/25) and 56% of adenocarcinoma (ADCs, 19/34), with SqCC showing the highest levels of methylation. Higher SPARC methylation levels were significantly associated with higher mortality risk both in all NSCLCs early stage patients (Hazard Ratio, HR = 1.97; 95% Confidence Interval, CI: 1.32–2.93; p = 0.001) and in those with SqCC (HR = 2.96; 95% CI: 1.43–6.12; p = 0.003). Promoter methylation of SPARC gene should represent an interesting prognostic biomarker in NSCLC, with potential application in the squamous early-stage context. Further research in this setting on larger independent cohorts of lung patients with different histologies and stages of disease are warranted.

Macrophage-derived SPARC Attenuates M2-mediated Pro-tumour Phenotypes

Since the theory of seed and soil was put forward, people have increasingly recognized that the tumour microenvironment is an important regulator of tumour progression and therapeutic response. Among them, M2-type macrophages (M2, as the major macrophage subtype in the tumour foci) have important promoting effects on various biological behaviours. Secreted protein acidic and rich in cysteine (SPARC) is an important anti-tumour component in the microenvironment of gastric cancer. This study shows that macrophages are an important source of the SPARC and that SPARC overexpression in M2 can reduce M2-mediated promoting proliferation, migration and anti-apoptotic effects in gastric cancer. Additionally, the AKT/mTOR signalling pathways may participate in the malignant process.

Hypermethylation of N-Acetyltransferase 1 Is a Prognostic Biomarker in Colon Adenocarcinoma

Background: The N-acetyltransferase 1 (NAT1) gene is downregulated in several cancers and associated with patient survival. In this study, we sought to examine the prognostic value and clinical significance of NAT1 methylation in colon adenocarcinoma (COAD).

Methods: Data relating to NAT1 mRNA expression and methylation and clinicopathological features of COAD were extracted from the database of The Cancer Genome Atlas. We compared the mRNA expression and methylation of NAT1 between COAD and normal tissues and performed correlation analysis to assess the association between NAT1 mRNA expression and methylation. Furthermore, we assessed patient survival based on CpG sites in the promoter region of NAT1 and analyzed the association between the NAT1 mRNA expression and CpG site methylation and clinicopathological features. An independent Gene Expression Omnibus (GEO) dataset was used to validate the results.

Results: We found that the expression of NAT1 mRNA was reduced in COAD compared with normal tissues and that mean methylation of the eight CpG sites in the promoter region of NAT1 was higher in COAD tissues than in normal tissues. Furthermore, five CpG sites were demonstrated to be significantly negatively correlated with NAT1 mRNA expression in COAD. Survival analysis indicated that NAT1 mRNA expression and the cg15797286 and cg18509990 sites were associated with the overall survival of COAD patients. Combined survival analysis revealed that combinations of NAT1 mRNA expression with five CpG sites were significantly associated with the overall survival of COAD patients. Both NAT1 mRNA and cg15797286 were associated with the T, N, and clinical stages of COAD. The GEO data indicated that cg15797286 was hypermethylated in recurrent colorectal adenomas.

Conclusions: Methylation of NAT1 is associated with the development of COAD, and may serve as prognostic and treatment biomarkers for COAD.

Low expression of SPARC in gastric cancer-associated fibroblasts leads to stemness transformation and 5-fluorouracil resistance in gastric cancer

Background

The aim of the present study was to clarify the correlations between SPARC expression in gastric cancer-associated fibroblasts (GCAFs) and the prognosis of patients with gastric cancer and to elucidate the role of GCAF-derived SPARC in stemness transformation and 5-fluorouracil resistance in gastric cancer.

Methods

One hundred ninety-two patients were enrolled in the present study. SPARC expression levels were evaluated by immunohistochemical staining. Primary GCAFs were obtained and cultured from cancer patients for in vitro study, and a lentivirus infection method was employed to knock down SPARC expression in GCAFs. The stemness phenotype and 5-fluorouracil (5-FU) response of gastric cancer cells were assessed via a 3D co-culture model. The apoptotic status and stemness alterations were monitored by flow cytometry and western blotting. Additionally, label-free quantification proteomics was used to identify the differentially expressed proteins and potential pathways in gastric cancer cells treated with GCAF-derived SPARC.

Results

Low expression of GCAF-derived SPARC was associated with decreased differentiation and reduced 5-year overall survival and was an independent predictive factor for prognosis in gastric cancer. The 3D tumour growth and 5-FU resistance abilities of gastric cancer cells were elevated after treatment with GCAFs with SPARC knockdown relative to these abilities in negative control cells. Additionally, suppressing SPARC expression in GCAFs facilitated the phenotypic alteration of gastric cancer cells towards CD44⁺/CD24⁻ cancer stem cell (CSC)-like cells. Quantification proteomics analysis revealed that the differentially expressed proteins in gastric cancer cells were mainly involved in the AKT/mTOR and MEK/ERK signalling pathways.

Conclusions

SPARC expression in GCAFs is a useful prognostic factor in patients with gastric cancer. Low expression of GCAF-derived SPARC can lead to CSC transformation and 5-FU resistance. Additionally, the AKT/mTOR and MEK/ERK signalling pathways may participate in the malignant process.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0844-8) contains supplementary material, which is available to authorized users.

Prognostic value of differentially methylated gene profiles in bladder cancer

DNA methylation can regulate gene expression and is pivotal in the occurrence and development of bladder cancer. In this study, we analyzed whole-genome DNA methylation on the basis of data from The Cancer Genome Atlas to select epigenetic biomarkers predictive of survival and further understand the molecular mechanisms underlying methylation patterns in bladder cancer. We identified 540 differentially methylated genes between tumor and normal tissues, including a number of independent prognostic factors based on univariate analysis. Genes (MIR6732, SOWAHC, SERPINI1, OR10W1, OR7G3, AIM1, and ZFAND5) were integrated to establish a risk model for prognostic assessment based on multivariate Cox analysis. The methylation of SOWAHC was negatively correlated with its messenger RNA expression, and together these were significantly correlated with prognosis. This study took advantage of high-throughput data mining to provide new bioinformatics evidence and ideas for further study into the pathogenesis and prognosis of bladder cancer.

Identification of DNA methylation-driven genes in esophageal squamous cell carcinoma: a study based on The Cancer Genome Atlas

Background

Aberrant DNA methylations are significantly associated with esophageal squamous cell carcinoma (ESCC). In this study, we aimed to investigate the DNA methylation-driven genes in ESCC by integrative bioinformatics analysis.

Methods

Data of DNA methylation and transcriptome profiling were downloaded from TCGA database. DNA methylation-driven genes were obtained by methylmix R package. David database and ConsensusPathDB were used to perform gene ontology (GO) analysis and pathway analysis, respectively. Survival R package was used to analyze overall survival analysis of methylation-driven genes.

Results

Totally 26 DNA methylation-driven genes were identified by the methylmix, which were enriched in molecular function of DNA binding and transcription factor activity. Then, ABCD1, SLC5A10, SPIN3, ZNF69, and ZNF608 were recognized as significant independent prognostic biomarkers from 26 methylation-driven genes. Additionally, a further integrative survival analysis, which combined methylation and gene expression data, was identified that ABCD1, CCDC8, FBXO17 were significantly associated with patients’ survival. Also, multiple aberrant methylation sites were found to be correlated with gene expression.

Conclusion

In summary, we studied the DNA methylation-driven genes in ESCC by bioinformatics analysis, offering better understand of molecular mechanisms of ESCC and providing potential biomarkers precision treatment and prognosis detection.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0770-9) contains supplementary material, which is available to authorized users.

mRNA and miRNA expression profiling of follicular variant of papillary thyroid carcinoma with and without distant metastases

Follicular Variant of Papillary Thyroid Carcinoma (FVPTC) is usually associated with a good outcome. Nevertheless, in rare cases, it develops distant metastases (1-9%). Our goal was to investigate whether mRNA and miRNA expression profiles may help distinguish between metastatic versus non-metastatic FVPTCs. Twenty-four primary FVPTCs, 12 metastatic and 12 non-metastatic, with similar clinicopathological features were selected and analyzed by nanoString nCounter technology using two distinct panels for expression analysis of 740 mRNA and 798 miRNAs. Data analysis was performed using the nanoString nSolver 3.0 software. Forty-seven mRNA and 35 miRNAs were differentially expressed between the two groups. Using these mRNA and miRNAs, metastatic and non-metastatic FVPTCs were clearly divided into two distinct clusters. Our results indicate that FVPTCs with metastatic abilities have different expression profiles compared to the non-metastatic. A prospective validation is needed to evaluate the usefulness of this molecular approach in the early identification of high-risk FVPTCs.

Diagnostic role of circulating extracellular matrix-related proteins in non-small cell lung cancer

Background

Interactions between cancer cells and the surrounding microenvironment are crucial determinants of cancer progression. During this process, bi-directional communication among tumor cells and cancer associated fibroblasts (CAF) regulate extracellular matrix (ECM) deposition and remodeling. As a result of this dynamic process, soluble ECM proteins can be released into the bloodstream and may represent novel circulating biomarkers useful for cancer diagnosis. The aim of the present study was to measure the levels of three circulating ECM related proteins (COL11A1, COL10A1 and SPARC) in plasma samples of lung cancer patients and in healthy heavy-smokers controls and test whether such measurements have diagnostic or prognostic value.

Methods

Gene expression profiling of lung fibroblasts isolated from paired normal and cancer tissue of NSCLC patients was performed by gene expression microarrays. The prioritization of the candidates for the study of circulating proteins in plasma was based on the most differentially expressed genes in cancer associated fibroblasts. Soluble ECM proteins were assessed by western blot in the conditioned medium of lung fibroblasts and by ELISA assays in plasma samples.

Results

Plasma samples from lung cancer patients and healthy heavy-smokers controls were tested for levels of COL11A1 and COL10A1 (n = 57 each) and SPARC (n = 90 each). Higher plasma levels of COL10A1 were detected in patients (p ≤ 0.001), a difference that was driven specifically by females (p < 0.001). No difference in COL11A1 levels between patients and controls was found. SPARC levels were also higher in plasma patients than controls (p < 0.001) with good performance in discriminating the two groups (AUC = 0.744). No significant association was observed between plasma proteins levels and clinicopathological features or survival.

Conclusion

Soluble factors related to proficient tumor-stroma cross-talk are detectable in plasma of primary lung cancer patients and may represent a valuable complementary diagnostic tool to discriminate lung cancer patients from healthy heavy-smokers individuals as shown for the SPARC protein.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4772-0) contains supplementary material, which is available to authorized users.

Epigenetic biomarkers in gastrointestinal cancers: The current state and clinical perspectives

Each year, almost 4.1 million people are diagnosed with gastrointestinal (GI) cancers. Due to late detection of this disease, the mortality is high, causing approximately 3 million cancer-related deaths annually, worldwide. Although the incidence and survival differs according to organ site, earlier detection and improved prognostication have the potential to reduce overall mortality burden from these cancers. Epigenetic changes, including aberrant promoter DNA methylation, are common events in both cancer initiation and progression. Furthermore, such changes may be identified non-invasively with the use of PCR based methods, in bodily fluids of cancer patients. These features make aberrant DNA methylation a promising substrate for the development of disease biomarkers for early detection, prognosis and for predicting response to therapy. In this article, we will provide an update and current clinical perspectives for DNA methylation alterations in patients with colorectal, gastric, pancreatic, liver and esophageal cancers, and discuss their potential role as cancer biomarkers.

Association of peripheral blood leukocyte KIBRA methylation with gastric cancer risk: a case-control study

KIBRA was reported to be involved in various types of cancer and can be detected in blood. The purpose of this study was to investigate the relationship between the status of KIBRA methylation in peripheral blood leukocytes and gastric cancer (GC) risk. A case-control study was carried out to evaluate the association of blood cell-derived KIBRA methylation with the risk of GC using methylation-sensitive high-resolution melting analysis. A total of 393 cases and 393 controls were detected, respectively. Compared with the subjects in the KIBRA negative methylation (NM) group, positive methylation (PM) subjects exhibited a 1.52-fold (95% CI: 1.030-2.251, P = 0.035) increased risk for GC. Stratified analyses demonstrated that the significant association of KIBRA methylation with GC risk existed in the older group (≥ 60 years; ORa  = 1.846, 95% CI: 1.037-3.287, P = 0.037) and Helicobacter pylori (H. pylori) positive subjects (ORa  = 1.933, 95% CI: 1.103-3.386, P = 0.021). Statistically significant combination effects between the environmental factors and KIBRA methylation on the GC risk were observed except for storing food under refrigeration. KIBRA methylation derived from blood cells and combinations thereof with environmental factors may be associated with the risk of GC.

Integrated analysis of genome-wide DNA methylation and gene expression profiles identifies potential novel biomarkers of rectal cancer

DNA methylation was regarded as the promising biomarker for rectal cancer diagnosis. However, the optimal methylation biomarkers with ideal diagnostic performance for rectal cancer are still limited. To identify new molecular markers for rectal cancer, we mapped DNA methylation and transcriptomic profiles in the six rectal cancer and paired normal samples. Further analysis revealed the hypermethylated probes in cancer prone to be located in gene promoter. Meanwhile, transcriptome analysis presented 773 low-expressed and 1,161 over-expressed genes in rectal cancer. Correction analysis identified a panel of 36 genes with an inverse correlation between methylation and gene expression levels, including 10 known colorectal cancer related genes. From the other 26 novel marker genes, GFRA1 and GSTM2 were selected for further analysis on the basis of their biological functions. Further experiment analysis confirmed their methylation and expression status in a larger number (44) of rectal cancer samples, and ROC curves showed higher AUC than SEPT9, which has been used as a biomarker in rectal cancer. Our data suggests that aberrant DNA methylation of contiguous CpG sites in methylation array may be potential diagnostic markers of rectal cancer.

SPARC is down-regulated by DNA methylation and functions as a tumor suppressor in T-cell lymphoma

The aim of this study was to assess the functional role of SPARC in T-cell non-Hodgkin's lymphoma (T-NHL), as well as the underlying molecular mechanisms. Here, we first identified SPARC expression in T-NHL tissues and cell lines through western blot and real-time PCR (RT-PCR). Overall survival of T-NHL patients with different levels of SPARC was assessed by Kaplan-Meier survival curves. Then cell proliferation, apoptosis, migration and invasion of T-NHL cells with either knockdown or overexpression of SPARC were determined by MTT, flow cytometry, transwell migration and invasion assay, respectively. Finally, the molecular mechanism by which SPARC modulated T-NHL cell progression was assessed. We confirmed that SPARC was significantly down-regulated in T-NHL tissues and cell lines. T-NHL patients with high levels of SPARC demonstrated a favorable clinical outcome. SPARC significantly suppressed cell proliferation, migration and invasion, and EMT process, but facilitated cell apoptosis in T-NHL cells. Further, we found that loss of SPARC expression in T-NHL tissues and cell lines, both in mRNA and protein levels, was associated with the aberrant DNA methylation in SPRAC gene, and the disrupted SPARC expression could be rescued after treatment with the demethylating agent 5-Aza-2'-deoxycitydine (5-Aza-Cdr). Additionally, 5-Aza-Cdr reversed SPARC hypermethylation to restore its biological role as a tumor suppressor in T-NHL cells, including inhibiting cell proliferation, invasion and migration, while promoting cell apoptosis. Our data provided evidence that DNA methylation in SPARC gene may play a role in the progression of T-NHL.

Short stature homeobox 2 methylation as a potential noninvasive biomarker in bronchial aspirates for lung cancer diagnosis

Gene methylation has been frequently observed in lung cancer. However, the use of methylated genes in bronchial aspirates of patients with lung cancer remains to be evaluated. The purpose of this study was to analyze whether the detection of genes with aberrant promoter methylation can be useful noninvasive biomarkers in bronchial aspirates from lung cancer. We found that the methylation status of the cyclin-dependent kinase inhibitor 2A (P16), Ras association domain family 1 isoform (RASSF1A), adenomatous polyposis coli (APC) and short stature homeobox 2 (SHOX2) genes was significantly correlated with lung cancer in bronchial aspirates. The P16, RASSF1A and APC methylation had a bad diagnostic effect in bronchial aspirates of patients with lung cancer compared with non-tumor controls (P16: sensitivity = 0.26, specificity = 0.99, area under the curve (AUC) = 0.67; RASSF1A: sensitivity = 0.40, specificity = 0.99, AUC = 0.66; APC: sensitivity = 0.17, specificity = 0.98, AUC = 0.65). The pooled sensitivity, specificity, and AUC of the SHOX2 methylation were 0.75, 0.94, and 0.94, respectively. Moreover, when squamous cell carcinoma (SCC) was compared to adenocarcinoma (AC), the SHOX2 gene had a significantly higher methylation rate in SCC than in AC (P < 0.001). Methylated P16, RASSF1A, APC and retinoic acid receptor beta2 (RARβ2) genes had similar frequencies in these two histotypes (P > 0.1). Our findings suggest that methylated SHOX2 gene could be a specific and potential noninvasive biomarker using bronchial aspirates for lung cancer diagnosis, especially for SCC.

Extracellular calcium-binding peptide-modified ceramics stimulate regeneration of calvarial bone defects

Secreted protein, acidic, cysteine-rich (SPARC)-related modular calcium binding 1 (SMOC1) has been implicated in the regulation of osteogenic differentiation of human bone marrow mesenchymal stem cells (BMSCs). In this study, we found that a peptide (16 amino acids in length), which is located in the extracellular calcium (EC) binding domain of SMOC1, stimulated osteogenic differentiation of human BMSCs in vitro and calvarial bone regeneration in vivo. Treatment of BMSCs with SMOC1-EC peptide significantly stimulated their mineralization in a dose-dependent manner without changing their rate of proliferation. The expression of osteogenic differentiation marker genes, including type 1 collagen and osteocalcin, also increased in a dose-dependent manner. To examine the effect of the SMOC1-EC peptide on bone formation in vivo, the peptide was covalently immobilized onto hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) particles. X-ray photoelectron spectroscopy analysis showed that the peptide was successfully immobilized onto the surface of HA/β-TCP. Implantation of the SMOC1-EC peptide-immobilized HA/β-TCP particles into mouse calvarial defects and subsequent analyses using microcomputed tomography and histology showed significant bone regeneration compared with that of calvarial defects implanted with unmodified HA/β-TCP particles. Collectively, our data suggest that a peptide derived from the EC domain of SMOC1 induces osteogenic differentiation of human BMSCs in vitro and efficiently enhances bone regeneration in vivo.

The secreted protein acidic and rich in cysteine is a critical mediator of cell death program induced by WIN/TRAIL combined treatment in osteosarcoma cells

Secreted protein acidic and rich in cysteine (SPARC) is a multi-functional protein which modulates cell-cell and cell-matrix interactions. In cancer cells, SPARC behaves as a tumor promoter in a number of tumors, but it can also act as a tumor suppressor factor. Our previous results showed that the synthetic cannabinoid WIN55,212-2 (WIN), a potent cannabinoid receptor agonist, is able to sensitize osteosarcoma MG63 cells to TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis which is accompanied with endoplasmic reticulum (ER)-stress induction and the increase in autophagic markers. In the present investigation, we studied the role of SPARC in WIN/TRAIL-induced apoptosis demonstrating that WIN increased the level of SPARC protein and mRNA in a time-dependent manner. This event was functional to WIN/TRAIL-dependent apoptosis as demonstrated by RNA interfering analysis which indicated that SPARC-silenced cells were less sensitive to cytotoxic effects induced by the combined treatment. Our experiments also demonstrate that SPARC interacts with caspase-8 thus probably favoring its translocation to plasma membrane and the activation of extrinsic apoptotic pathway. In conclusion, to the best of our knowledge, our results are the first to show that WIN-dependent increase in the level of SPARC plays a critical role in sensitizing osteosarcoma cells to TRAIL action.

CD90 is upregulated in gastric cancer tissues and inhibits gastric cancer cell apoptosis by modulating the expression level of SPARC protein

Cluster of differentiation 90 (CD90) (Thy-1) plays important roles in the oncogenesis in various types of malignancies. In the present study, we investigated the expression of CD90 in gastric cancer (GC) tissues by q-PCR, immunohistochemistry (IHC), and western blot technologies. The results showed that CD90 was overexpressed in gastric cancer tissues compared with the level in the adjacent non‑cancerous tissues. To explore the possible mechanism of CD90 in GC, we elucidated the effect of CD90 on the apoptosis of AGS gastric cancer cells, and found that a considerable decrease in apoptotic cells was observed for AGS cells with CD90 overexpression. Meanwhile, the rate of apoptotic cells was increased in the AGS cells with CD90 interference (siCD90) compared with that in the AGS cells. Cell apoptosis is closely related to a reduction in mitochondrial membrane potential (ΔΨm) and an increase in intracellular reactive oxygen species (ROS) and calcium ion (Ca2+) concentrations. Our results showed that overexpression of CD90 in the AGS gastric cancer cells led to an increase in ΔΨm and a decrease in intracellular ROS and Ca2+ concentrations. At the same time, siCD90 reduced ΔΨm and the increase in intracellular ROS and Ca2+ concentrations. Furthermore, we identified and confirmed that CD90 functions by modulating the expression level of secreted protein, acidic, cysteine‑rich (osteonectin) (SPARC) in vitro through LC‑MS/MS analyses and western blot technology. In summary, our results suggest that CD90 is upregulated in gastric cancer and inhibits gastric cancer cell apoptosis by modulating the expression level of SPARC protein.