Expression of serum amyloid A transcripts in human bone tissues, differentiated osteoblast-like stem cells and human osteosarcoma cell lines

Multi-omics analysis of a case of congenital microtia reveals aldob and oxidative stress associated with microtia etiology

BACKGROUND

Microtia is reported to be one of the most common congenital craniofacial malformations. Due to the complex etiology and the ethical barrier of embryonic study, the precise mechanisms of microtia remain unclear. Here we report a rare case of microtia with costal chondrodysplasia based on bioinformatics analysis and further verifications on other sporadic microtia patients.

RESULTS

One hundred fourteen deleterious insert and deletion (InDel) and 646 deleterious SNPs were screened out by WES, candidate genes were ranked in descending order according to their relative impact with microtia. Label-free proteomic analysis showed that proteins significantly different between the groups were related with oxidative stress and energy metabolism. By real-time PCR and immunohistochemistry, we further verified the candidate genes between other sporadic microtia and normal ear chondrocytes, which showed threonine aspartase, cadherin-13, aldolase B and adiponectin were significantly upregulated in mRNA levels but were significantly lower in protein levels. ROS detection and mitochondrial membrane potential (∆ Ψ m) detection proved that oxidative stress exists in microtia chondrocytes.

CONCLUSIONS

Our results not only spot new candidate genes by WES and label-free proteomics, but also speculate for the first time that metabolism and oxidative stress may disturb cartilage development and this might become therapeutic targets and potential biomarkers with clinical usefulness in the future.

Enhanced bone regeneration via endochondral ossification using Exendin-4-modified mesenchymal stem cells

Nonunions and delayed unions pose significant challenges in orthopedic treatment, with current therapies often proving inadequate. Bone tissue engineering (BTE), particularly through endochondral ossification (ECO), emerges as a promising strategy for addressing critical bone defects. This study introduces mesenchymal stem cells overexpressing Exendin-4 (MSC-E4), designed to modulate bone remodeling via their autocrine and paracrine functions. We established a type I collagen (Col-I) sponge-based in vitro model that effectively recapitulates the ECO pathway. MSC-E4 demonstrated superior chondrogenic and hypertrophic differentiation and enhanced the ECO cell fate in single-cell sequencing analysis. Furthermore, MSC-E4 encapsulated in microscaffold, effectively facilitated bone regeneration in a rat calvarial defect model, underscoring its potential as a therapeutic agent for bone regeneration. Our findings advocate for MSC-E4 within a BTE framework as a novel and potent approach for treating significant bone defects, leveraging the intrinsic ECO process.

Maternal siRNA silencing of placental SAA2 mitigates preterm birth following intrauterine inflammation

The placental inflammatory processes induced maternally result in preterm birth (PTB). Serum amyloid A (SAA) is a well-known biomarker of inflammation. The objective of this study was to investigate whether murine placental SAA isoforms (SAA1–4) participate in the mechanism of spontaneous PTB and whether maternal regulation of SAA production may serve as a therapeutic approach. During the gestation, all isoforms of SAA were detectable except SAA2. The mouse model of intrauterine inflammation was established using LPS infusion to the uterus. Following intrauterine inflammation, placental SAA2 increased significantly. Inhibition of Saa2, using siSaa2, markedly decreased PTB. The increased placental expression of pro-inflammatory cytokines Il1β, Il6, and Tnfα were downregulated by siSaa2 treatment. Maternal inhibition of Saa2 did not change the expression of Saa1–4 in the fetal brain. Explant inflammatory culture of placentas with siSaa2 showed similar results to our in vivo experiments. This study demonstrates the highly expressed placental SAA2 as a novel therapeutic target, and maternal administration of siRNA as a promising approach to alleviate PTB.

Immune infiltration-associated serum amyloid A1 predicts favorable prognosis for hepatocellular carcinoma

BACKGROUND

Serum amyloid A1 (SAA1) is an acute-phase protein involved in acute or chronic hepatitis. Its function is still controversial. In addition, the effect of the expression of SAA1 and its molecular function on the progression in hepatocellular carcinoma (HCC) is still unclear.

AIM

To demonstrate the expression of SAA1 and its effect on the prognosis in HCC and explain further the correlation of SAA1 and immunity pathways.

METHODS

SAA1 expression in HCC was conducted with The Cancer Genome Atlas-Liver Hepatocellular Carcinoma (TCGA-LIHC) in GEPIA tool, and the survival analysis based on the SAA1 expression level was achieved in the Kaplan-Meier portal. The high or low expression group was then drawn based on the median level of SAA1 expression. The correlation of SAA1 and the clinical features were conducted in the UALCAN web-based portal with TCGA-LIHC, including tumor grade, patient disease stage, and the TP53 mutation. The correlation analysis between SAA1 expression and TP53 mutation was subjected to the TCGA portal. The tumor purity score and the immune score were analyzed with CIBERSORT. The correlation of SAA1 expression and tumor-infiltrating lymphocytes was achieved in TISIDB web-based integrated repository portal for tumor-immune system interactions. GSE125336 dataset was used to test the SAA1 expression in the responsive or resistant group with anti-PD1 therapy. Gene set enrichment analysis was applied to evaluate the gene enrichment signaling pathway in HCC. The similar genes of SAA1 in HCC were identified in GEPIA, and the protein-protein interaction of SAA1 was conducted in the Metascape tool. The expression of C-X-C motif chemokine ligand 2, C-C motif chemokine ligand 23, and complement C5a receptor 1 was studied and overall survival analysis in HCC was conducted in GEPIA and Kaplan-Meier portal, respectively.

RESULTS

SAA1 expression was decreased in HCC, and lower SAA1 expression predicted poorer overall survival, progression-free survival, and disease-specific survival. Furthermore, SAA1 expression was further decreased with increased tumor grade and patient disease stage. Also, SAA1 expression was further downregulated in patients with TP53 mutation compared with patients with wild type TP53. SAA1 expression was negatively correlated with the TP53 mutation. Lower SAA1 predicted poorer survival rate, especially in the patients with no hepatitis virus infection, other than those with hepatitis virus infection. Moreover, the SAA1 expression was negatively correlated with tumor purity. In contrast, SAA1 expression was positively correlated with the immune score in HCC, and the correlation analysis between SAA1 expression and tumor-infiltrating lymphocytes also showed a positive correlation in HCC. Decreased SAA1 was closely associated with the immune tolerance of HCC. C-X-C motif chemokine ligand 2 and C-C motif chemokine ligand 23 genes were identified as the hub genes associated with SAA1, which could also serve as favorable prognosis markers for HCC.

CONCLUSION

SAA1 is downregulated in the liver tumor, and it is closely involved in the progression of HCC. Lower SAA1 expression indicates lower survival rate, especially for those patients without hepatitis virus infection. Lower SAA1 expression also suggests lower immune infiltrating cells, especially for those with immune cells exerting anti-tumor immune function. SAA1 expression is closely associated with the anti-tumor immune pathways.

Development of a prognostic gene signature based on an immunogenomic infiltration analysis of osteosarcoma

Osteosarcoma is the most common primary malignant bone tumour predominantly occurring in children and adolescents with a high tendency of local invasion and early metastases. Currently, tumour immune microenvironment (TME) is becoming the focus of studying of malignant tumours.. However, no sound evidence shows a specific immune molecular target in osteosarcoma. We downloaded the gene expression profile and clinical data of osteosarcoma from the TARGET portal, and extracted and normalized via R software. Then, the immune cell infiltration assessed by CIBERSORT and ESTIMATE algorithms. Three survival‐related immune cells and immune score were obtained via Kaplan‐Meier survival analysis, and 232 immune‐related genes were obtained as candidate genes. Enrichment and protein‐protein interaction co‐expression analyses were performed to identify 13 hub genes. Lastly, a seven gene prognostic signature was identified by univariate and multivariate Cox regression analyses. More importantly, our validations and TIMER algorithm suggested this immune‐related prognostic signature a good predictive tool. Our findings have provided novel insights that could demonstrate new targets of immunotherapy in osteosarcoma.

The host response to bacterial bone infection involves a local upregulation of several acute phase proteins

Bone infections often become chronic and can be difficult to diagnose. In the present study, the osseous gene expression of several acute phase proteins (APPs) during osteomyelitis was investigated in a porcine model of implant associated osteomyelitis (IAO) (sampled 5, 10 and 15 days after infection) and in slaughter pigs with spontaneous hematogenous osteomyelitis, and compared to gene expression in liver tissue. Furthermore, immunohistochemical (IHC) staining of the APP complement component C3 (C3) was performed on the porcine osteomyelitis lesions together with material from human patients with chronic osteomyelitis. In the porcine bone samples a local upregulation of the expression of several APP genes, including serum amyloid A (SAA) and C3, was observed during infection. In the liver, only C-reactive protein (CRP) and Inter-Alpha-Trypsin Inhibitor Heavy Chain 4 were significantly upregulated. Serum concentrations of CRP, SAA and haptoglobin were only upregulated at day 5 in infected animals of the IAO model. This indicates a limited systemic response to osteomyelitis. Similar numbers of positive IHC stained C3 leukocytes were found in human and porcine bone samples with chronic osteomyelitis, indicating a high transcriptional value of porcine models of osteomyelitis. The local upregulation of APPs could potentially be used for diagnosing osteomyelitis.

Serum Amyloid A is Expressed in the Brain After Traumatic Brain Injury in a Sex-Dependent Manner

Serum amyloid A (SAA) is an acute phase protein upregulated in the liver after traumatic brain injury (TBI). So far, it has not been investigated whether SAA expression also occurs in the brain in response to TBI. For this, we performed a moderate controlled cortical impact injury in adult male and female mice and analyzed brain, blood, and liver samples at 6 h, 1, 3, and 10 days post-injury (dpi). We measured the levels of SAA in serum, brain and liver by western blot. We also used immunohistochemical techniques combined with in situ hybridization to determine SAA mRNA and protein expression in the brain. Our results revealed higher levels of SAA in the bloodstream in males compared to females at 6 h post-TBI. Liver and serum SAA protein showed a peak of expression at 1 dpi followed by a decrease at 3 to 10 dpi in both sexes. Both SAA mRNA and protein expression colocalize with astrocytes and macrophages/microglia in the cortex, corpus callosum, thalamus, and hippocampus after TBI. For the first time, here we show that SAA is expressed in the brain in response to TBI. Collectively, SAA expression was higher in males compared to females, and in association with the sex-dependent neuroinflammatory response after brain injury. We suggest that SAA could be a crucial protein associated to the acute neuroinflammation following TBI, not only for its hepatic upregulation but also for its expression in the injured brain.

Interleukin-1β Induces Intracellular Serum Amyloid A1 Expression in Human Coronary Artery Endothelial Cells and Promotes its Intercellular Exchange

Serum amyloid A (SAA) is an acute-phase protein with important, pathogenic role in the development of atherosclerosis. Since dysfunctional endothelium represents a key early step in atherogenesis, we aimed to determine whether induced human coronary artery endothelial cells (HCAEC) modulate SAA1/2/4 expression and influence intracellular location and intercellular transport of SAA1. HCAEC were stimulated with 1 ng/ml IL-1β, 10 ng/ml IL-6, and/or 1 μM dexamethasone for 24 h. QPCR, Western blots, ELISA, and immunofluorescent labeling were performed for detection of SAA1/2/4 mRNA and protein levels, respectively. In SAA1 transport experiments, FITC- or Cy3-labeled SAA1 were added to HCAEC separately, for 24 h, followed by a combined incubation of SAA1-FITC and SAA1-Cy3 positive cells, with IL-1β and analysis by flow cytometry. IL-1β upregulated SAA1 (119.9-fold, p < 0.01) and SAA2 (9.3-fold; p < 0.05) mRNA expression levels, while mRNA expression of SAA4 was not affected. Intracellular SAA1 was found mainly as a monomer, while SAA2 and SAA4 formed octamers as analyzed by Western blots. Within HCAEC, SAA1/2/4 located mostly to the perinuclear area and tunneling membrane nanotubes. Co-culturing of SAA1-FITC and SAA1-Cy3 positive cells for 48 h showed a significantly higher percentage of double positive cells in IL-1β-stimulated (mean ± SD; 60 ± 4%) vs. non-stimulated cells (48 ± 2%; p < 0.05). IL-1β induces SAA1 expression in HCAEC and promotes its intercellular exchange, suggesting that direct communication between cells in inflammatory conditions could ultimately lead to faster development of atherosclerosis in coronary arteries.

Acute phase reactant serum amyloid A in inflammation and other diseases

Acute-phase reactant serum amyloid A (A-SAA) plays an important role in acute and chronic inflammation and is used in clinical laboratories as an indicator of inflammation. Although both A-SAA and C-reactive protein (CRP) are acute-phase proteins, the detection of A-SAA is more conclusive than the detection of CRP in patients with viral infections, severe acute pancreatitis, and rejection reactions to kidney transplants. A-SAA has greater clinical diagnostic value in patients who are immunosuppressed, patients with cystic fibrosis who are treated with corticoids, and preterm infants with late-onset sepsis. Nevertheless, for the assessment of the inflammation status and identification of viral infection in other pathologies, such as bacterial infections, the combinatorial use of A-SAA and other acute-phase proteins (APPs), such as CRP and procalcitonin (PCT), can provide more information and sensitivity than the use of any of these proteins alone, and the information generated is important in guiding antibiotic therapy. In addition, A-SAA-associated diseases and the diagnostic value of A-SAA are discussed. However, the relationship between different A-SAA isotypes and their human diseases are mostly derived from research laboratories with limited clinical samples. Thus, further clinical evaluations are necessary to confirm the clinical significance of each A-SAA isotype. Furthermore, the currently available A-SAA assays are based on polyclonal antibodies, which lack isotype specificity and are associated with many inflammatory diseases. Therefore, these assays are usually used in combination with other biomarkers in the clinic.

Potential functions of long non‑coding RNAs in the osteogenic differentiation of human bone marrow mesenchymal stem cells

Long non-coding RNAs (lncRNAs) are a specific group of RNA molecules that do not encode proteins. They have been shown to serve important regulatory functions in various biological and cell differentiation processes. However, the potential functions and regulatory mechanisms of lncRNAs that are associated with the osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) remain to be elucidated. The present study aimed to investigate lncRNAs that are differentially expressed during the osteogenic differentiation of hBMSCs, along with the potential functions of those lncRNAs. To this end, three groups of hBMSCs were stimulated to undergo osteogenic differentiation for 7 days. Known lncRNAs, unknown lncRNAs and mRNAs that demonstrated differential expression prior to and following the osteogenic differentiation of hBMSCs were screened using lncRNA high-throughput sequencing. In addition, 12 lncRNAs were selected for reverse transcription-quantitative polymerase chain reaction (RT-qPCR) validation of the accuracy of the sequencing results. The potential functions and possible targets of the differentially expressed lncRNAs were analyzed using bioinformatics technologies (gene ontology, Kyoto Encyclopedia of Genes and Genomes and gene co-expression network analysis). In total, 64 lncRNAs were differentially expressed by at least two-fold in hBMSCs prior to and following osteogenic differentiation; these included seven known lncRNAs (two upregulated and five downregulated lncRNAs) and 57 unknown lncRNAs (35 upregulated and 22 downregulated lncRNAs). In addition, 409 mRNAs (257 upregulated and 152 downregulated mRNAs) were differentially expressed by at least two-fold. The RT-qPCR results obtained for 12 selected differentially expressed lncRNAs were consistent with the sequencing results. The gene co-expression network analysis of lncRNAs and mRNAs demonstrated that four lncRNAs (ENSG00000238042, lnc_1269, lnc_1369 and lnc_1708) may serve important roles in the osteogenic differentiation of hBMSCs. In conclusion, during the osteogenic differentiation of hBMSCs, the lncRNA expression profile changed significantly; certain of the observed differentially expressed lncRNAs may be derived from protein-coding genes and may serve important roles in osteogenic differentiation.

Serum amyloid A - a review

Serum amyloid A (SAA) proteins were isolated and named over 50 years ago. They are small (104 amino acids) and have a striking relationship to the acute phase response with serum levels rising as much as 1000-fold in 24 hours. SAA proteins are encoded in a family of closely-related genes and have been remarkably conserved throughout vertebrate evolution. Amino-terminal fragments of SAA can form highly organized, insoluble fibrils that accumulate in “secondary” amyloid disease. Despite their evolutionary preservation and dynamic synthesis pattern SAA proteins have lacked well-defined physiologic roles. However, considering an array of many, often unrelated, reports now permits a more coordinated perspective. Protein studies have elucidated basic SAA structure and fibril formation. Appreciating SAA’s lipophilicity helps relate it to lipid transport and metabolism as well as atherosclerosis. SAA’s function as a cytokine-like protein has become recognized in cell-cell communication as well as feedback in inflammatory, immunologic, neoplastic and protective pathways. SAA likely has a critical role in control and possibly propagation of the primordial acute phase response. Appreciating the many cellular and molecular interactions for SAA suggests possibilities for improved understanding of pathophysiology as well as treatment and disease prevention.

Pigs are useful for the molecular study of bone inflammation and regeneration in humans

Pigs are used with increased frequency to model different kinds of orthopedic surgical conditions. In order to show the full potential of porcine models in orthopedic research, it is therefore required to examine the expression of bone regulatory genes in pigs affected by orthopedic surgery and compare it to the expression in humans and mice as mice, are one of the most applied animal species in orthopedics today. In the present study, the local molecular response to drilling of a tibial implant cavity, and the subsequent insertion of a steel implant was examined in a porcine model. Pigs were euthanized five days after drilling of the bone. The molecular response of 73 different genes was analyzed using a high-throughput quantitative polymerase chain reaction platform and compared to histopathology. Histologically, it was found that bone remodeling was initiated on day 5 after surgery and was associated with upregulation of several genes involved in bone degradation and formation ( CTSK, ACP5, IBSP, RANK, RANKL and COL1A1). Interleukin-6 and several acute-phase proteins (C3, SAA and ITIH4) were significantly upregulated, indicating their importance in the initial process of healing and osseointegration. All tested bone morphogenic proteins (BMP2, -4 and -7) including their inhibitor noggin were also significantly upregulated. Surprisingly, vascular endothelial growth factor A was not found to be regulated five days after surgery while several other vascular growth factors (ANGPT1, ANGPT2 and PTN) were upregulated. The pig was found to be a useful model for elucidation of bone regulatory genes in humans.

The prognostic significance of circulating serum amyloid A and CXC chemokine ligand 4 in osteosarcoma

BACKGROUND

Osteosarcoma (OS) is the most common pediatric bone cancer.  Despite advances in treatment regimens, the survival rate remains 60-70%.  There is an urgent need to identify prognostic biomarkers, so that targeted therapies can be developed to improve the outcome.

PROCEDURE

Our laboratory has previously identified that circulating serum amyloid A (SAA) and CXC chemokine ligand 4 (CXCL4) are upregulated in patients with OS.  In this study, we tested if they could be used as prognostic biomarkers.  We used enzyme-linked immunosorbent assays to measure their concentrations in serum samples (n = 233) and immunohistochemistry to examine their expressions in primary tumors (n = 37).  Prognostic significance of the serum concentrations and tumor expressions of the biomarkers was then evaluated.

RESULTS

Patients with "high SAA" and "low CXCL4" circulating levels at diagnosis significantly correlated with a worse outcome (HR = 1.68, P = 0.014), which was independent of the metastatic status.  These patients also exhibited a significantly higher rate of poor histologic response to chemotherapy.  Furthermore, low tumor expression of CXCL4 correlated with poor survival (HR = 3.57, P = 0.005).

CONCLUSIONS

Our results demonstrate that circulating SAA and CXCL4 may serve as prognostic biomarkers in OS.  Targeting CXCL4 has been reported, suggesting that it may be exploited as a therapeutic target in OS.

The impact of gallic acid on the methotrexate-induced kidney damage in rats

Prolonged use of an antineoplastic agent methotrexate (MTX), can cause numerous side effects such as nephrotoxicity. The aim of this study was to examine the effects of MTX on kidneys and demonstrate the protective effects of gallic acid (GA). Twenty-four, male, rats distributed into three groups. Each groups consisted eight rats and only saline was administered to the control group. The MTX group received a single dose (20 mg/kg) MTX intraperitoneally. The MTX + GA group received same dose MTX and 100 mg/kg GA orally during the 7 days. Renal functions, oxidative stress markers, histopathological and immunohistochemical changes were evaluated at the end of the experiment. Blood urea nitrogen, creatinine, uric acid levels and tissue oxidative stress markers, total oxidant status and oxidative stress index levels significantly increased and total antioxidant status levels significantly decreased in MTX group compared with the control group. At the histopathological examination hemorrhages, tubular cell necrosis, glomerulosclerosis, inflammatory cell infiltrations and proteinous materials in tubules were noticed in MTX group. Immunohistochemical examination revealed that increased expressions of serum amyloid A (SAA), tumor necrosis factor alpha (TNF-α), prostaglandin E2 (PGE-2) and C-reactive protein (CRP) in tubular epithelial cells of kidneys in this group. There were no immunoreaction with SAA and CRP, only small number of PGE-2 and TNF-α positive tubular epithelial cells were observed in MTX + GA group. In conclusion, all evidence suggested that oxidative stress caused MTX-induced nephrotoxicity and GA prevent the kidney from the nephrotoxicity due to its antioxidant and anti-inflammatory activities.

Microglia activation due to obesity programs metabolic failure leading to type two diabetes

Obesity is an energy metabolism disorder that increases susceptibility to the development of metabolic diseases. Recently, it has been described that obese subjects have a phenotype of chronic inflammation in organs that are metabolically relevant for glucose homeostasis and energy. Altered expression of immune system molecules such as interleukins IL-1, IL-6, IL-18, tumor necrosis factor alpha (TNF-α), serum amyloid A (SAA), and plasminogen activator inhibitor-1 (PAI-1), among others, has been associated with the development of chronic inflammation in obesity. Chronic inflammation modulates the development of metabolic-related comorbidities like metabolic syndrome (insulin resistance, glucose tolerance, hypertension and hyperlipidemia). Recent evidence suggests that microglia activation in the central nervous system (CNS) is a priority in the deregulation of energy homeostasis and promotes increased glucose levels. This review will cover the most significant advances that explore the molecular signals during microglia activation and inflammatory stage in the brain in the context of obesity, and its influence on the development of metabolic syndrome and type two diabetes.

Structure and Expression of Different Serum Amyloid A (SAA) Variants and their Concentration-Dependent Functions During Host Insults

Serum amyloid A (SAA) is, like C-reactive protein (CRP), an acute phase protein and can be used as a diagnostic, prognostic or therapy follow-up marker for many diseases. Increases in serum levels of SAA are triggered by physical insults to the host, including infection, trauma, inflammatory reactions and cancer. The order of magnitude of increase in SAA levels varies considerably, from a 10- to 100-fold during limited inflammatory events to a 1000-fold increase during severe bacterial infections and acute exacerbations of chronic inflammatory diseases. This broad response range is reflected by SAA gene duplications resulting in a cluster encoding several SAA variants and by multiple biological functions of SAA. SAA variants are single-domain proteins with simple structures and few post-translational modifications. SAA1 and SAA2 are inducible by inflammatory cytokines, whereas SAA4 is constitutively produced. We review here the regulated expression of SAA in normal and transformed cells and compare its serum levels in various disease states. At low concentrations (10-100 ng/ml), early in an inflammatory response, SAA induces chemokines or matrix degrading enzymes via Toll-like receptors and functions as an activator and chemoattractant through a G protein-coupled receptor. When an infectious or inflammatory stimulus persists, the liver continues to produce more SAA (> 1000 ng/ml) to become an antimicrobial agent by functioning as a direct opsonin of bacteria or by interference with virus infection of host cells. Thus, SAA regulates innate and adaptive immunity and this information may help to design better drugs to treat specific diseases.

PEDF Is Associated with the Termination of Chondrocyte Phenotype and Catabolism of Cartilage Tissue

Objective. To investigate the expression and target genes of pigment epithelium-derived factor (PEDF) in cartilage and chondrocytes, respectively. Methods. We analyzed the expression pattern of PEDF in different human cartilaginous tissues including articular cartilage, osteophytic cartilage, and fetal epiphyseal and growth plate cartilage, by immunohistochemistry and quantitative real-time (qRT) PCR. Transcriptome analysis after stimulation of human articular chondrocytes with rhPEDF was performed by RNA sequencing (RNA-Seq) and confirmed by qRT-PCR. Results. Immunohistochemically, PEDF could be detected in transient cartilaginous tissue that is prone to undergo endochondral ossification, including epiphyseal cartilage, growth plate cartilage, and osteophytic cartilage. In contrast, PEDF was hardly detected in healthy articular cartilage and in the superficial zone of epiphyses, regions that are characterized by a permanent stable chondrocyte phenotype. RNA-Seq analysis and qRT-PCR demonstrated that rhPEDF significantly induced the expression of a number of matrix-degrading factors including SAA1, MMP1, MMP3, and MMP13. Simultaneously, a number of cartilage-specific genes including COL2A1, COL9A2, COMP, and LECT were among the most significantly downregulated genes. Conclusions. PEDF represents a marker for transient cartilage during all neonatal and postnatal developmental stages and promotes the termination of cartilage tissue by upregulation of matrix-degrading factors and downregulation of cartilage-specific genes. These data provide the basis for novel strategies to stabilize the phenotype of articular cartilage and prevent its degradation.

The impact of methotrexate on lung inflammatory and apoptotic pathway biomarkers-The role of gallic acid

BACKGROUNDS

The aim of this study was to investigate the effects of methotrexate (MTX) on the lung via inflammatory and apoptotic pathway biomarkers and the role of gallic acid (GA).

METHODS

In this study, twenty four male Wistar-Albino rats weighing 300-350g were divided into 3 groups as follows; Control group (0.1ml/oral saline, for 7 days+2nd day i.p.). MTX group (20mg/kg, single dose, on 2nd day). MTX+GA group (15mg/kg, orally, for 7 days). Comet analysis, oxidant-antioxidant status, IMA were conducted. Histopathological analyses were evaluated.

RESULTS

Comet assay on the blood, TOS and OSI values in the lung were increased in the group II compared with the control group (p<0.05). GA significantly reduced the comet score and IMA levels in the blood, TOS and OSI values in the lung tissue in group III compared with group II (p<0.05). Immunohistochemically PGE₂, TNF-α, CRP, serum SAA, Caspase 3 and Caspase 9 expressions significantly increased in group II compared with the control group (p<0.001) and GA treatment ameliorated these parameters significantly in group III compared with group II (p<0.001).

CONCLUSIONS

MTX caused oxidative stress and DNA damage in the blood tissue and caused oxidative damage, inflammation and apoptosis in the lung tissue.

Acute phase proteins as promising biomarkers: Perspectives and limitations for human and veterinary medicine

Acute phase proteins (APPs) are highly conserved plasma proteins that are increasingly secreted by the liver in response to a variety of injuries, independently of their location and cause. APPs favor the systemic regulation of defense, coagulation, proteolysis, and tissue repair. Various APPs have been applied as general diagnostic parameters for a long time. Through proteomic techniques, more and more APPs have been discovered to be differentially altered. Since they are not consistently explainable by a stereotypic hepatic expression of sets of APPs, most of these results have unfortunately been neglected or attributed to the nonspecificity of the acute phase reaction. Moreover, it appears that various extrahepatic tissues are also able to express APPs. These extrahepatic APPs show focally specific roles in tissue homeostasis and repair and are released primarily into interstitial and distal fluids. Since these focal proteins might leak into the circulatory system, mixtures of hepatic and extrahepatic APP species can be expected in blood. Hence, a selective alteration of parts of APPs might be expected. There are several hints on multiple molecular forms and fragments of tissue-derived APPs. These differences offer the chance for multiple selective determinations. Thus, specific proteoforms might indeed serve as tissue-specific disease indicators.

The cytokine-serum amyloid A-chemokine network

Levels of serum amyloid A (SAA), a major acute phase protein in humans, are increased up to 1000-fold upon infection, trauma, cancer or other inflammatory events. However, the exact role of SAA in host defense is yet not fully understood. Several pro- and anti-inflammatory properties have been ascribed to SAA. Here, the regulated production of SAA by cytokines and glucocorticoids is discussed first. Secondly, the cytokine and chemokine inducing capacity of SAA and its receptor usage are reviewed. Thirdly, the direct (via FPR2) and indirect (via TLR2) chemotactic effects of SAA and its synergy with chemokines are unraveled. Altogether, a complex cytokine-SAA-chemokine network is established, in which SAA plays a key role in regulating the inflammatory response.

Serum Amyloid A3 Secreted by Preosteoclasts Inhibits Parathyroid Hormone-stimulated cAMP Signaling in Murine Osteoblasts

Continuous parathyroid hormone (PTH) blocks its own osteogenic actions in marrow stromal cell cultures by inducing Cox2 and receptor activator of nuclear factor κB ligand (RANKL) in the osteoblastic lineage cells, which then cause the hematopoietic lineage cells to secrete an inhibitor of PTH-stimulated osteoblast differentiation. To identify this inhibitor, we used bone marrow macrophages (BMMs) and primary osteoblasts (POBs) from WT and Cox2 knock-out (KO) mice. Conditioned medium (CM) from RANKL-treated WT, but not KO, BMMs blocked PTH-stimulated cAMP production in POBs. Inhibition was reversed by pertussis toxin (PTX), which blocks Gαi/o activation. Saa3 was the most highly differentially expressed gene in a microarray comparison of RANKL-treated WT versus Cox2 KO BMMs, and RANKL induced Saa3 protein secretion only from WT BMMs. CM from RANKL-stimulated BMMs with Saa3 knockdown did not inhibit PTH-stimulated responses in POBs. SAA added to POBs inhibited PTH-stimulated cAMP responses, which was reversed by PTX. Selective agonists and antagonists of formyl peptide receptor 2 (Fpr2) suggested that Fpr2 mediated the inhibitory actions of Saa3 on osteoblasts. In BMMs committed to become osteoclasts by RANKL treatment, Saa3 expression peaked prior to appearance of multinucleated cells. Flow sorting of WT marrow revealed that Saa3 was secreted only from the RANKL-stimulated B220(-) CD3(-)CD11b(-/low) CD115(+) preosteoclast population. We conclude that Saa3 secretion from preosteoclasts, induced by RANKL in a Cox2-dependent manner, inhibits PTH-stimulated cAMP signaling and osteoblast differentiation via Gαi/o signaling. The induction of Saa3 by PTH may explain the suppression of bone formation when PTH is applied continuously and may be a new therapeutic target for osteoporosis.

Acute phase serum amyloid A induces proinflammatory cytokines and mineralization via toll-like receptor 4 in mesenchymal stem cells

The role of serum amyloid A (SAA) proteins, which are ligands for toll-like receptors, was analyzed in human bone marrow-derived mesenchymal stem cells (hMSCs) and their osteogenic offspring with a focus on senescence, differentiation and mineralization. In vitro aged hMSC developed a senescence-associated secretory phenotype (SASP), resulting in enhanced SAA1/2, TLR2/4 and proinflammatory cytokine (IL6, IL8, IL1β, CXCL1, CXCL2) expression before entering replicative senescence. Recombinant human SAA1 (rhSAA1) induced SASP-related genes and proteins in MSC, which could be abolished by cotreatment with the TLR4-inhibitor CLI-095. The same pattern of SASP-resembling genes was stimulated upon induction of osteogenic differentiation, which is accompanied by autocrine SAA1/2 expression. In this context additional rhSAA1 enhanced the SASP-like phenotype, accelerated the proinflammatory phase of osteogenic differentiation and enhanced mineralization. Autocrine/paracrine and rhSAA1 via TLR4 stimulate a proinflammatory phenotype that is both part of the early phase of osteogenic differentiation and the development of senescence. This signaling cascade is tightly involved in bone formation and mineralization, but may also propagate pathological extraosseous calcification conditions such as calcifying inflammation and atherosclerosis.

Acute-phase protein serum amyloid A3 is a novel paracrine coupling factor that controls bone homeostasis

Serum amyloid A (A-SAA/Saa3) was shown before to affect osteoblastic metabolism. Here, using RT-quantitative PCR and/or immunoblotting, we show that expression of mouse Saa3 and human SAA1 and SAA2 positively correlates with increased cellular maturation toward the osteocyte phenotype. Expression is not detected in C3H10T1/2 embryonic fibroblasts but is successively higher in preosteoblastic MC3T3-E1 cells, late osteoblastic MLO-A5 cells, and MLO-Y4 osteocytes, consistent with findings using primary bone cells from newborn mouse calvaria. Recombinant Saa3 protein functionally inhibits osteoblast differentiation as reflected by reductions in the expression of osteoblast markers and decreased mineralization in newborn mouse calvaria. Yet, Saa3 protein enhances osteoclastogenesis in mouse macrophages/monocytes based on the number of multinucleated and tartrate-resistant alkaline phosphatase-positive cells and Calcr mRNA expression. Depletion of Saa3 in MLO osteocytes results in the loss of the mature osteocyte phenotype. Recombinant osteocalcin, which is reciprocally regulated with Saa3 at the osteoblast/osteocyte transition, attenuates Saa3 expression in MLO-Y4 osteocytes. Mechanistically, Saa3 produced by MLO-Y4 osteocytes is integrated into the extracellular matrix of MC3T3-E1 osteoblasts, where it associates with the P2 purinergic receptor P2rx7 to stimulate Mmp13 expression via the P2rx7/MAPK/ERK/activator protein 1 axis. Our data suggest that Saa3 may function as an important coupling factor in bone development and homeostasis.

Expression of serum amyloid A4 in human trophoblast-like choriocarcinoma cell lines and human first trimester/term trophoblast cells

Trophoblast invasion into uterine tissues represents a hallmark of first trimester placental development. As expression of serum amyloid A4 (SAA4) occurs in tumorigenic and invasive tissues we here investigated whether SAA4 is present in trophoblast-like human AC1-M59/Jeg-3 cells and trophoblast preparations of human first trimester and term placenta. SAA4 mRNA was expressed in non-stimulated and cytokine-treated AC1-M59/Jeg-3 cells. In purified trophoblast cells SAA4 mRNA expression was upregulated at weeks 10 and 12 of pregnancy. Western-blot and immunohistochemical staining of first trimester placental tissue revealed pronounced SAA4 expression in invasive trophoblast cells indicating a potential role of SAA4 during invasion.

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SAA4 mRNA is expressed in Jeg-3 and AC1-M59 cells.

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SAA4 mRNA is expressed in first trimester/term trophoblast cells.

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SAA4 mRNA is upregulated at pregnancy week 10 and 12.

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SAA4 protein is present in interstitial, intramural and intraluminal trophoblast cells.

Modeling clear cell sarcomagenesis in the mouse: cell of origin differentiation state impacts tumor characteristics

Clear cell sarcoma (CCS) of tendons and aponeuroses is a deadly soft-tissue malignancy resembling melanoma, with a predilection for young adults. EWS-ATF1, the fusion product of a balanced chromosomal translocation between chromosomes 22 and 12, is considered the definitional feature of the tumor. Conditional expression of the EWS-ATF1 human cDNA in the mouse generates CCS-like tumors with 100% penetrance. Tumors, developed through varied means of initiating expression of the fusion oncogene, model human CCS morphologically, immunohistochemically, and by genome-wide expression profiling. We also demonstrate that although fusion oncogene expression in later stages of differentiation can transform mesenchymal progenitor cells and generate tumors resembling CCS generally, expression in cells retaining stem cell markers permits the full melanoma-related phenotype.

Homocysteine induces serum amyloid A3 in osteoblasts via unlocking RGD-motifs in collagen

Hyperhomocysteinemia is a risk factor for osteoporotic fractures. Homocysteine (Hcys) inhibits collagen cross-linking and consequently decreases bone extracellular matrix (ECM) quality. Serum amyloid A (A-SAA), an acute-phase protein family, plays an important role in chronic and inflammatory diseases and up-regulates MMP13, which plays an important role in bone development and remodeling. Here, we investigate the effect of Hcys on expression of SAA3, a member of the A-SAA gene family, in osteoblasts characterizing underlying mechanisms and possible consequences on bone metabolism. MC3T3-E1 osteoblast-like cells were cultured up to 21 d with Hcys (low millimolar range) or reseeded onto ECM resulting from untreated or Hcys-treated MC3T3-E1 cells. Fourier-transformed infrared spectroscopy and a discriminative antibody were used to characterize the resulting ECM. Gene expression and signaling pathways were analyzed by gene chip, quantitative RT-PCR, and immunoblotting. Transcriptional regulation of Saa3 was studied by promoter transfection assays, chromatin immunoprecipitation, and immunofluorescence microscopy. Hcys treatment resulted in reduced collagen cross-linking, uncovering of RGD-motifs, and activation of the PTK2-PXN-CTNNB1 pathway followed by RELA activation. These signaling events led to increased SAA3 expression followed by the production of MMP13 and several chemokines, including Ccl5, Ccl2, Cxcl10, and Il6. Our data suggest Saa3 as link between hyperhomocysteinemia and development of osteoporosis.

DNA methylation plasticity of human adipose-derived stem cells in lineage commitment

Adult stem cells have an enormous potential for clinical use in regenerative medicine that avoids many of the drawbacks characteristic of embryonic stem cells and induced pluripotent stem cells. In this context, easily obtainable human adipose-derived stem cells offer an interesting option for future strategies in regenerative medicine. However, little is known about their repertoire of differentiation capacities, how closely they resemble the target primary tissues, and the potential safety issues associated with their use. DNA methylation is one of the most widely recognized epigenetic factors involved in cellular identity, prompting us to consider how the analyses of 27,578 CpG sites in the genome of these cells under different conditions reflect their different natural history. We show that human adipose-derived stem cells generate myogenic and osteogenic lineages that share much of the DNA methylation landscape characteristic of primary myocytes and osteocytes. Most important, adult stem cells and in vitro-generated myocytes and osteocytes display a significantly different DNA methylome from that observed in transformed cells from these tissue types, such as rhabdomyosarcoma and osteosarcoma. These results suggest that the plasticity of the DNA methylation patterns plays an important role in lineage commitment of adult stem cells and that it could be used for clinical purposes as a biomarker of efficient and safely differentiated cells.

LPA-induced suppression of periostin in human osteosarcoma cells is mediated by the LPA(1)/Egr-1 axis

Lysophosphatidic acid (LPA), a naturally occurring bioactive phospholipid, mediates a multitude of (patho)physiological events including activation of mitogen-activated protein kinases (MAPKs). As LPA may induce cellular reponses in human osteosarcoma, the present study aimed at investigating expression of various LPA receptors, LPA-mediated activation of MAPK via G-protein coupling, and expression of early response genes in a cellular model for human osteosarcoma. We show that MG-63 cells express three members of the endothelial differentiation gene (Edg) family of G-protein coupled receptor transcripts (LPA(1-3)) but only two (LPA(4/5)) out of three members of the non-Edg family LPA receptor transcripts. Stimulation of MG-63 cells with LPA or synthetic LPA receptor agonists resulted in p42/44 MAPK phosphorylation via LPA(1)-LPA(3) receptors. Using pharmacological inhibitors, we show that LPA-mediated phosphorylation of p42/44 MAPK by LPA receptor engagement is transmitted by G(αi)-dependent pathways through the Src family of tyrosine kinases. As a consequence, a rapid and transient upregulation of the zinc finger transcription factor early growth response-1 (Egr-1) was observed. Egr-1 expression was strictly mediated via G(αi)/Src/p42/44 MAPK pathway; no involvement of the G(αq/11)/PLC/PKC or the PLD/PI3 kinase/Akt pathways was found. LPA-induced expression of functional Egr-1 in MG-63 cells could be confirmed by electrophoretic mobility shift assay. LPA-induced Egr-1 upregulation was accompanied by a time-dependent decrease of periostin (previously called osteoblast-specific factor 2), a cell adhesion protein for pre-osteoblasts. Silencing of LPA(1) and/or Egr-1 in MG-63 cells reversed LPA-mediated suppression of periostin. We here demonstrate a crosslink between Egr-1 and periostin in cancer cells, in particular in human osteosarcoma.

Monocytes induce STAT3 activation in human mesenchymal stem cells to promote osteoblast formation

A major therapeutic challenge is how to replace bone once it is lost. Bone loss is a characteristic of chronic inflammatory and degenerative diseases such as rheumatoid arthritis and osteoporosis. Cells and cytokines of the immune system are known to regulate bone turnover by controlling the differentiation and activity of osteoclasts, the bone resorbing cells. However, less is known about the regulation of osteoblasts (OB), the bone forming cells. This study aimed to investigate whether immune cells also regulate OB differentiation. Using in vitro cell cultures of human bone marrow-derived mesenchymal stem cells (MSC), it was shown that monocytes/macrophages potently induced MSC differentiation into OBs. This was evident by increased alkaline phosphatase (ALP) after 7 days and the formation of mineralised bone nodules at 21 days. This monocyte-induced osteogenic effect was mediated by cell contact with MSCs leading to the production of soluble factor(s) by the monocytes. As a consequence of these interactions we observed a rapid activation of STAT3 in the MSCs. Gene profiling of STAT3 constitutively active (STAT3C) infected MSCs using Illumina whole human genome arrays showed that Runx2 and ALP were up-regulated whilst DKK1 was down-regulated in response to STAT3 signalling. STAT3C also led to the up-regulation of the oncostatin M (OSM) and LIF receptors. In the co-cultures, OSM that was produced by monocytes activated STAT3 in MSCs, and neutralising antibodies to OSM reduced ALP by 50%. These data indicate that OSM, in conjunction with other mediators, can drive MSC differentiation into OB. This study establishes a role for monocyte/macrophages as critical regulators of osteogenic differentiation via OSM production and the induction of STAT3 signalling in MSCs. Inducing the local activation of STAT3 in bone cells may be a valuable tool to increase bone formation in osteoporosis and arthritis, and in localised bone remodelling during fracture repair.

Plasma proteomic profiling of pediatric osteosarcoma

The development of a sensitive, specific, and non-invasive approach for cancer detection will facilitate early detection and, hence, improve the outcome of individuals with known cancer predispositions. Proteomic profiling of blood emerges to be a logical choice of such non-invasive or minimal invasive detection. However, plasma biomarker discovery of pediatric cancers lags behind that of adult cancers, suggesting more efforts are needed in this area. In this study, we used surface-enhanced laser desorption/ionization-time of flight mass spectrometry to profile plasma proteome in osteosarcoma patients. Osteosarcoma is a bone cancer that affects many children and young adults. We have shown that the plasma proteome contains a unique cancer signature that can distinguish patients with osteosarcoma from those with a benign bone disease. To improve cancer biomarker discovery in plasma, we have also shown that depletion of two highly abundant plasma proteins increases the detection sensitivity of lower-abundance proteins. The combination of depletion and proteomic profiling may increase the chance of identifying tumor-derived proteins within the plasma of pediatric cancer patients.

Identification of potential serum biomarkers for Wilms tumor after excluding confounding effects of common systemic inflammatory factors

Wilms tumor is the most common pediatric tumor of the kidney. Previous studies have identified several serum biomarkers for Wilms tumor; however, they lack sufficient specificity and may not adequately distinguish Wilms tumor from confounding conditions. To date, no specific protein biomarker has been confirmed for this pediatric tumor. To identify novel serum biomarkers for Wilms tumor, we used proteomic technologies to perform protein profiling of serum samples from pre-surgery and post-surgery patients with Wilms tumor and healthy controls. Some common systemic inflammatory factors were included to control for systemic inflammation. By comparing protein peaks among the three groups of sera, we identified two peaks (11,526 and 4,756 Da) showing significant differential expression not only between pre-surgery and control sera but also between pre-surgery and post-surgery sera. These two peaks were identified as serum amyloid A1 (SAA1) and apolipoprotein C-III (APO C-III). Western blot analysis confirmed that both proteins were expressed at higher levels in pre-surgery sera than in post-surgery and control sera. Using the method of leave-1-out for cross detection, we demonstrate that detection of these two candidate biomarkers had high sensitivity and specificity in discriminating pre-surgery sera from post-surgery and normal control sera. Taken together, these findings suggest that SAA1 and APO C-III are two potential biomarkers for Wilms tumor.

Serum biomarkers which correlate with failure to respond to immunotherapy and tumor progression in a murine colorectal cancer model

PURPOSE

To advance our understanding of mechanisms involved in tumor progression/regression, a CT26 colorectal mouse model treated intra-tumorally with DISC-herpes simplex virus as immunotherapy was used in the discovery and validation phases to investigate and ultimately identify biomarkers correlating with the failure to respond to immunotherapy.

EXPERIMENTAL DESIGN

For the discovery phase, serum protein/peptide profiles of a retrospective sample collection (total n=70) were analyzed using MALDI-TOF-MS combined with artificial neural networks. Following identification of the key predictive peptides using ESI-MS/MS, validation of the identified proteins was carried out on serum and tissues collected in an independent sample set (total n=60).

RESULTS

Artificial neural network analysis resulted in four discriminatory peaks with an accuracy of 86%, sensitivity of 90% and specificity of 81% between the progressor/regressor groups. Three of the identified discriminatory markers were upregulated and demonstrated a positive correlation with tumor progression following DISC-herpes simplex virus therapy. Immunovalidation studies corroborated the MALDI-TOF-MS findings. Immunohistochemistry revealed that serum amyloid A-1 and serum amyloid P produced in the liver localized intracellularly in CT26 tumor tissue.

CONCLUSIONS

MALDI-TOF-MS and BI analysis of the serum proteome of tumor-bearer mice undergoing immunotherapy, identified biomarkers associating with "failure to respond" and biological arrays confirmed these findings.

Production of Serum Amyloid a in Response to Inflammatory Cytokines by Human Adipocytes

Serum amyloid A (SAA) is a major acute-phase protein in humans, and elevated plasma levels represent a risk factor for cardiovascular diseases. SAA was thought to be produced by hepatocytes only in response to inflammatory stimuli; moreover, recent studies have shown that adipose tissue can secrete several proinflammatory factors. Therefore, we investigated whether cells in adipose tissue can synthesize SAA in response to inflammatory stimuli. Adipocytes and preadipocytes isolated from abdominal adipose tissue were incubated with IL-1, IL-6, TNF-α, LPS, or resistin at different concentrations. After 48 hours, the supernatants were analyzed by ELISAs for human SAA. Preadipocytes did not show any production in SAA. In contrast, in adipocytes, incubation with TNF-α led to a significant increase in SAA production, peaking after LPS or resistin (∼3 times greater vs unstimulated adipocytes). The greatest increase in SAA occurred with all stimuli combined (∼5 times greater vs control cells). Subsequently, we investigated whether treatment with some drugs could modulate SAA production in adipocytes, and observed that fluvastatin led to a significant inhibition of SAA release, whereas a larger modulation of SAA release was observed after treatment with troglitazone or aspirin. These results show for the first time that human adipocytes, and not preadipocytes, can produce SAA in response to inflammatory cytokines and that this process can be modulated.

Resistance exercise-induced changes of inflammatory gene expression within human skeletal muscle

Aberrant local inflammatory signaling within skeletal muscle is now considered a contributing factor to the development of sarcopenia. Recent evidence indicates that chronic resistance training contributes to the control of locally derived inflammation via adaptations to repeated, acute increases in pro-inflammatory mRNA within muscle. However, only a limited number of gene transcripts related to the inflammatory process have been examined in the literature. The present study utilized an acute bout to examine the effects of resistance exercise on several inflammatory-related genes in 24 physically active, post-menopausal women not currently undergoing hormone replacement therapy. Following a standard warm-up, participants completed a lower-body resistance exercise bout consisting of 3 sets of 10 repetitions on machine squat, leg press, and leg extension exercises (80% intensity). Muscle biopsies were obtained from the vastus lateralis of the dominant leg at baseline and 3 h following exercise. Significant (p < 0.05) up-regulation in mRNA content was observed for TNFalpha, IL1beta, IL6, IL8, SOCS2, COX2, SAA1, SAA2, IKKB, cfos, and junB. Muscle mRNA content was not significantly altered at the 0.05 level for IL2, IL5, IL10, or IL12 (p35). Venous blood samples were also obtained at baseline as well as at 3, 24, and 48 h post-exercise. Serum was analyzed for circulating TNFalpha, IL1beta, IL6, IL8, COX2, and SAA with no significant changes observed. These results indicate that resistance exercise is capable of up-regulating transcription of numerous inflammatory mediators within skeletal muscle, and these appear to be worthy of future examination in chronic studies.

SAF-3, a novel splice variant of the SAF-1/MAZ/Pur-1 family, is expressed during inflammation

The Cys2His2-type zinc finger transcription factor serum amyloid A activating factor 1 [SAF-1, also known as MAZ (myc-associated zinc finger protein) or Pur-1 (purine binding factor-1)] plays an important role in regulation of a variety of inflammation-responsive genes. An SAF-2 splice variant acting as a negative regulator of SAF-1 was identified previously, and the present study reports the identification of a novel SAF-3 splice variant that is expressed during inflammation. SAF-3 mRNA, isolated from a cDNA library produced from IL-1beta-induced cells, originates from a previously unknown first coding exon, and thereby contains a unique N-terminal domain but shares the same six zinc finger DNA-binding domains as present in SAF-1. In addition, a negatively functioning domain present at the N-terminus of SAF-1 and SAF-2 is spliced out in SAF-3. The expression of SAF-3 is very low in normal tissues and in cells grown under normal conditions. However, RT-PCR analysis of mRNAs from cytokine and growth factor-induced cells as well of mRNAs isolated from several diseased tissues revealed abundant expression of SAF-3. The transactivation potential of SAF-3 is much greater than that of the predominantly expressed splice variant SAF-1. These findings show that transcriptional regulation of downstream inflammation-responsive genes by SAF/MAZ/Pur-1 is likely to be more complex than previously assumed. In addition, we show that SAF-3 expression initiates from an upstream novel promoter. This is the first report of the existence of multiple promoters regulating expression of the SAF/MAZ/Pur-1 family of proteins.

Serum amyloid A: an acute-phase protein involved in tumour pathogenesis

The synthesis of acute-phase protein serum amyloid A (SAA) is largely regulated by inflammation- associated cytokines and a high concentration of circulating SAA may represent an ideal marker for acute and chronic inflammatory diseases. However, SAA is also synthesized in extrahepatic tissues, e.g. human carcinoma metastases and cancer cell lines. An increasing body of in vitro data supports the concept of involvement of SAA in carcinogenesis and neoplastic diseases. Accumulating evidence suggests that SAA might be included in a group of biomarkers to detect a pattern of physiological events that reflect the growth of malignancy and host response. This review is meant to provide a broad overview of the many ways that SAA could contribute to tumour development, and accelerate tumour progression and metastasis, and to gain a better understanding of this acute-phase reactant as a possible link between chronic inflammation and neoplasia.

Gene network and canonical pathway analysis in prostate cancer: a microarray study

The molecular mechanism playing a role in the development of prostate cancer (PCA) is not well defined. We decided to determine the changes in gene expression in PCA tissues and to compare them to those in non-cancerous samples. Prostate tissue samples were collected by needle biopsy from 21 PCA and 10 benign prostate hyperplasic (BPH) patients. Total RNA was isolated, cDNA was synthesized, and gene expression levels were determined by microarray method. In the progression to PCA, 738 up-regulated and 515 down-regulated genes were detected in samples. Analysis using Ingenuity Pathway Analysis (IPA) software revealed that 466 network and 423 functions-pathways eligible genes were up-regulated, and 363 network and 342 functions-pathways eligible genes were down-regulated. Up-regulated networks were identified around IL-1beta and insulin-like growth factor-1 (IGF-1) genes. The NFKB gene was centered around two up- and down-regulated networks. Up-regulated canonical pathways were assigned and four of them were evaluated in detail: acute phase response, hepatic fibrosis, actin cytoskeleton, and coagulation pathways. Axonal guidance signaling was the most significant down-regulated canonical pathway. Our data provide not only networks between the genes for understanding the biologic properties of PCA but also useful pathway maps for future understanding of disease and the construction of new therapeutic targets.