Biomarkers for prognosis of meningioma patients: A systematic review and meta-analysis

Meningioma is the most common primary brain tumor and many studies have evaluated numerous biomarkers for their prognostic value, often with inconsistent results. Currently, no reliable biomarkers are available to predict the survival, recurrence, and progression of meningioma patients in clinical practice. This study aims to evaluate the prognostic value of immunohistochemistry-based (IHC) biomarkers of meningioma patients. A systematic literature search was conducted up to November 2023 on PubMed, CENTRAL, CINAHL Plus, and Scopus databases. Two authors independently reviewed the identified relevant studies, extracted data, and assessed the risk of bias of the studies included. Meta-analyses were performed with the hazard ratio (HR) and 95% confidence interval (CI) of overall survival (OS), recurrence-free survival (RFS), and progression-free survival (PFS). The risk of bias in the included studies was evaluated using the Quality in Prognosis Studies (QUIPS) tool. A total of 100 studies with 16,745 patients were included in this review. As the promising markers to predict OS of meningioma patients, Ki-67/MIB-1 (HR = 1.03, 95%CI 1.02 to 1.05) was identified to associate with poor prognosis of the patients. Overexpression of cyclin A (HR = 4.91, 95%CI 1.38 to 17.44), topoisomerase II α (TOP2A) (HR = 4.90, 95%CI 2.96 to 8.12), p53 (HR = 2.40, 95%CI 1.73 to 3.34), vascular endothelial growth factor (VEGF) (HR = 1.61, 95%CI 1.36 to 1.90), and Ki-67 (HR = 1.33, 95%CI 1.21 to 1.46), were identified also as unfavorable prognostic biomarkers for poor RFS of meningioma patients. Conversely, positive progesterone receptor (PR) and p21 staining were associated with longer RFS and are considered biomarkers of favorable prognosis of meningioma patients (HR = 0.60, 95% CI 0.41 to 0.88 and HR = 1.89, 95%CI 1.11 to 3.20). Additionally, high expression of Ki-67 was identified as a prognosis biomarker for poor PFS of meningioma patients (HR = 1.02, 95%CI 1.00 to 1.04). Although only in single studies, KPNA2, CDK6, Cox-2, MCM7 and PCNA are proposed as additional markers with high expression that are related with poor prognosis of meningioma patients. In conclusion, the results of the meta-analysis demonstrated that PR, cyclin A, TOP2A, p21, p53, VEGF and Ki-67 are either positively or negatively associated with survival of meningioma patients and might be useful biomarkers to assess the prognosis.

Serum CCDC25 Levels as a Potential Marker for Metabolic Syndrome

BACKGROUND/AIM

Metabolic syndrome (MetS) stands as a significant risk for developing various severe health problems. Therefore, the discovery of biomarkers capable of predicting the progression of metabolic conditions is crucial for improving overall health outcomes. Recently, we reported that coiled-coil domain containing 25 (CCDC25) might be associated with key proteins involved in metabolic pathways, by bioinformatics analysis. Thus, we assumed that serum CCDC25 levels might have an association with MetS status.

PATIENTS AND METHODS

In this study, based on the modified National Cholesterol Education Program-Adult Treatment Panel III (modified NCEP-ATP III) criteria, the participants who had three or more of abnormal criteria were defined as MetS, and those who had 1 or 2 abnormal criteria as pre-MetS groups; those who had no abnormal criteria were classified as the healthy control (HC) group. Serum CCDC25 levels were measured using the dot blot assay.

RESULTS

The results showed that serum CCDC25 levels of the MetS group (0.072±0.026 ng/μl) were significantly higher (p<0.001) than that of pre-MetS (0.031±0.011 ng/μl) or HC groups (0.018±0.007 ng/μl). We can discern a consistent trend indicating that serum CCDC25 level is well correlated with the number of abnormal criteria of MetS of each participant. Although serum CCDC25 levels correlated with the distribution of all 5 MetS criteria, the highest correlation was seen in serum CCDC25 levels and triglyceride (TG) levels, with r=0.563, followed by systolic blood pressure (SBP) levels (r=0.557) and high-density lipoprotein-cholesterol (HDL-C) levels (r=-0.545).

CONCLUSION

CCDC25 showed correlations with all MetS parameters, particularly with TG, SBP, and HDL-C. This prompts speculation that heightened CCDC25 levels may indicate the development and/or progression of those MetS-associated diseases.

Development of a Prognostic Score for Cholangiocarcinoma Patients Using a Combination of Biochemical Parameters

BACKGROUND/AIM

Prognosis of cholangiocarcinoma (CCA), especially of intrahepatic CCA (iCCA), is poor primarily due to difficulties in earlier diagnosis. Since the majority of iCCA patients are elders, their prognosis cannot be correctly predicted by pathological features and/or resection status alone. Consideration for comorbidity and/or risks of subclinical diseases at diagnosis is critically necessary for the prediction of prognosis of iCCA patients. This study aimed to develop a simple but reliable scoring system for prognosis of iCCA patients at the time of diagnosis.

PATIENTS AND METHODS

Serum samples from 152 iCCA patients were collected, and four commonly used biochemical markers, serum aspartate aminotransferase, alkaline phosphatase, cystatin C and creatinine-based estimated glomerular filtration rate were measured. Then, the values of individual patients were scored as 0, 1, and 2 (low, medium, and high) by tertiles or clinically relevant cut-off points and summed to construct a prognostic score with a range between 0 to 8.

RESULTS

Patients with high scores of 2-4 and 5-8 exhibited significantly shorter survival times compared to those with low scores of 0-1 (Chi-square: 15.75, p<0.001). Cox regression analysis suggested that the score could be an independent predictor for the survival of iCCA patients. The odds of advanced tumor stage in high score iCCA patients (2-4 and 5-8) were 12.310 (95%CI=2.241-67.605) and 23.964 (95%CI=3.296-174.216), respectively. This scoring system allowed further stratification of death rates per 100 person-years of iCCA patients.

CONCLUSION

The ability of such a simple scoring system to discriminate risk might be helpful for iCCA patients to determine therapeutic programs at the time of diagnosis.

High expression of protein tyrosine phosphatase receptor S (PTPRS) is an independent prognostic marker for cholangiocarcinoma

Cholangiocarcinoma (CCA) is an aggressive tumor of the bile duct with a high rate of mortality. Lymph node metastasis is an important factor facilitating the progression of CCA. A reliable biomarker for diagnosis, progression status, or prognosis of CCA is still lacking. To identify a novel and reliable biomarker for diagnosis/prognosis of CCA, liquid chromatography-mass spectrometry and tandem mass spectrometry (LC-MS/MS) in combination with bioinformatics analysis were applied for the representative serum samples of patients with CCA. The proteome results showed that protein tyrosine phosphatase receptor S (PTPRS) had the highest potential candidate. Then, a dot blot assay was used to measure the level of serum PTPRS in patients with CCA (n = 80), benign biliary disease patients (BBD; n = 39), and healthy controls (HC; n = 55). PTPRS level of CCA sera (14.38 ± 9.42 ng/ml) was significantly higher than that of BBD (10.7 ± 5.05 ng/ml) or HC (6 ± 3.73 ng/ml) (P < 0.0001). PTPRS was associated with serum albumin (P = 0.028), lymph node metastasis (P = 0.038), and the survival time of patients (P = 0.011). Using a log-rank test, higher serum PTPRS level was significantly (P = 0.031) correlated with a longer overall survival time of patients with CCA, and PTPRS was an independent prognostic marker for CCA superior to carbohydrate antigen 19-9 (CA19-9), carcinoembryonic antigen (CEA) or alkaline phosphatase (ALP). High expression of PTPRS could be a good independent prognostic marker for CCA.

Prediction of Angiopoietin-like Protein 4-related Signaling Pathways in Cholangiocarcinoma Cells

BACKGROUND/AIM

Angiopoietin-like protein 4 (ANGPTL4) is a multifunctional signaling protein implicated in carbohydrate metabolism, inflammation, cancer growth and progression, anoikis resistance, angiogenesis, and metastasis. However, signaling pathways of ANGPTL4 in cholangiocarcinoma (CCA) remain unknown. The aim of this study was to explore ANGPTL4-related signaling proteins and pathways associated with CCA biology.

MATERIALS AND METHODS

ANGPTL4 of CCA cells was silenced by small interfering RNA (siRNA) with scramble control and ANGPTL4-related signaling proteins were investigated using mass spectrometry, bioinformatics tools and molecular docking.

RESULTS

Among the 321 differentially expressed proteins, 151 were down-regulated. Among them, bioinformatic analyses revealed that ANGPTL4 interacts with DNA-dependent protein kinase catalytic subunit (PRKDC) and 60S ribosomal protein L21 (RPL21) via AKT serine/threonine kinase 1 (AKT1), mechanistic target of rapamycin kinase (MTOR) and ribosomal protein L5 (RPL5). Online database analysis showed that mRNA and protein expression levels of ANGPTL4-related signaling proteins were significantly higher in CCA than in normal tissues. Moreover, a high mRNA expression level was associated with high tumor grade (p<0.0001) and lymph node metastasis (p<0.0001).

CONCLUSION

The signaling pathway of ANGPTL4 in CCA progression might be regulated by PRKDC and RPL21. Furthermore, high expression of ANGPTL4-related signaling proteins has potential to be used in clinical prognosis.

Serum Angiopoietin-Like Protein 4: A Potential Prognostic Biomarker for Prediction of Vascular Invasion and Lymph Node Metastasis in Cholangiocarcinoma Patients

Cholangiocarcinoma (CCA) is a tumor arising from cholangiocytes lining the bile ducts. Vascular invasion and lymph node metastasis are important prognostic factors for disease staging as well as clinical therapeutic decisions for CCA patients. In the present study, we applied CCA sera proteomic analysis to identify a potential biomarker for prognosis of CCA patients. Then, using bioinformatics tools, we identified angiopoietin-like protein 4 (ANGPTL4) which expressed highest signal intensity among candidate proteins in proteomic analysis of CCA sera. Expression of ANGPTL4 in CCA tissues was determined using immunohistochemistry. The results showed that ANGPTL4 was stained at higher level in CCA cells when compared with normal cholangiocytes. The high expression of ANGPTL4 was associated with lymph node metastasis and advanced tumor stage (p = 0.013 and p = 0.031, respectively). Furthermore, serum ANGPTL4 levels in CCA and healthy control (HC) were analyzed using a dot blot assay. And it was found that ANGPTL4 level was significantly higher in CCA than HC group (p < 0.0001). ROC curve analysis revealed that serum ANGPTL4 level was effectively distinguished CCA from healthy patients (cutoff = 0.2697 arbitrary unit (AU), 80.0% sensitivity, 72.7% specificity, AUC = 0.825, p < 0.0001). Serum ANGPTL4 level was associated with vascular invasion and lymph node metastasis (p = 0.0004 and p = 0.006), so that it differentiated CCA with vascular invasion from CCA without vascular invasion (cutoff = 0.5526 AU, 64.9% sensitivity, 92.9% specificity, AUC = 0.751, p = 0.006) and it corresponded to CCA with/without lymph node metastasis (cutoff = 0.5399 AU, 71.4% sensitivity, 70.8% specificity, AUC = 0.691, p = 0.01) by ROC analysis. Serum ANGPTL4 levels showed superior predictive efficiency compared with CA 19-9 and CEA for vascular invasion and lymph node metastasis. In addition, serum ANGPTL4 level was an independent predictive indicator by multivariate regression analysis. In conclusion, serum ANGPTL4 could be a novel prognostic biomarker for prediction of vascular invasion and lymph node metastasis of CCA patients.

Bioinformatic Prediction of Novel Signaling Pathways of Apoptosis-inducing Factor, Mitochondrion-associated 3 (AIFM3) and Their Roles in Metastasis of Cholangiocarcinoma Cells

BACKGROUND/AIM

We previously demonstrated that a mitochondrial protein, apoptosis-inducing factor, mitochondrion-associated 3 (AIFM3) is over-expressed in cholangiocarcinoma (CCA) and its serum levels can be a prognostic biomarker for CCA. To elucidate the functional roles of AIFM3 in CCA progression, we aimed to determine the signaling pathways of AIFM3 in CCA.

MATERIALS AND METHODS

AIFM3 gene in CCA cells was silenced and AIFM3-related proteins were identified using mass spectrometry and bioinformatics tools. The relationships between AIFM3 and 441 related proteins were explored. To validate the functions of AIFM3, transwell migration/invasion assays were used.

RESULTS

Bioinformatic analyses predicted that AIFM3 interacts with formin-like protein 3 (FMNL3) and is involved in tumor cell motilities. Online database analysis revealed higher AIFM3 mRNA expression levels in CCA, particularly with lymph node metastasis. After AIFM3 gene silencing, CCA cell migration/invasion was significantly decreased (p<0.001). Furthermore, AIFM3 expression levels were significantly associated with lymph node metastasis (p=0.0009) and shorter survival time (p=0.020).

CONCLUSION

The AIFM3 signaling pathway is mediated via FMNL3 and involved in metastasis, suggesting that AIFM3 might be a molecular target to prevent CCA metastasis.

Serum Levels of Cytokine-Induced Apoptosis Inhibitor 1 (CIAPIN1) as a Potential Prognostic Biomarker of Cholangiocarcinoma

The mortality rate of cholangiocarcinoma (CCA) is high since there is a lack of a non-invasive technique to accurately detect tumors at the early stage. CCA biomarkers are consistently needed for various purposes including screening, early diagnosis, prognosis and follow-up. Herein, using bioinformatic analysis of our mitochondrial proteome database of CCA tissues, we identified cytokine-induced apoptosis inhibitor 1 (CIAPIN1) as a potential prognostic biomarker for CCA. CIAPIN1 levels in the sera of 159 CCA patients and 93 healthy controls (HC) were measured using a dot blot assay. The median level ± quartile deviation of CIAPIN1 level in the sera of CCA patient group was 0.5144 ± 0.34 µg/µL, which was significantly higher than 0.2427 ± 0.09 µg/µL of the HC group (p < 0.0001). In CCA patients, higher serum CIAPIN1 level was significantly associated with lymph node metastasis (p = 0.024) and shorter overall survival time (p = 0.001, Kaplan–Meier test). Cox regression analysis showed that the serum CIAPIN1 level can be an independent prognostic indicator for the survival of CCA patients. Moreover, for the prediction of CCA prognosis, CIAPIN1 is superior to CEA, CA19-9 and ALP. In conclusion, CIAPIN1 can be a serum biomarker candidate for the poor prognosis of CCA.

Kallikrein-11, in Association with Coiled-Coil Domain Containing 25, as a Potential Prognostic Marker for Cholangiocarcinoma with Lymph Node Metastasis

Cholangiocarcinoma (CCA) is a malignancy arising from cholangiocytes. Currently, the treatment and prognosis for CCA are mostly poor. Recently, we have reported that coiled-coil domain containing 25 (CCDC25) protein level in the sera may be a diagnostic marker for CCA. Subsequently, we identified three binding proteins of CCDC25 and found that kallikrein-11 (KLK11) expression was highest among those binding proteins. In this study, we investigated CCDC25 and KLK11 expression in CCA and adjacent normal tissues (n = 18) using immunohistochemistry. The results demonstrated that the expressions of CCDC25 and KLK11 in CCA tissues were both significantly higher than the adjacent tissues (p < 0.001 and p = 0.001, respectively). Then, using GEPIA bioinformatics analysis, KLK11 mRNA was significantly overexpressed in CCA tumor tissues compared with normal tissues (p < 0.05). Moreover, CCDC25 expression was positively correlated with KLK11 expression in CCA with lymph node metastasis (p = 0.028, r = 0.593). An analysis for the interaction of KLK11 with CCDC25 and other proteins, using STRING version 11.0, revealed that CCDC25 and KLK11 correlated with metastasis-related proteins. In addition, Kaplan-Meier survival curve analysis revealed that a high expression of KLK11 was associated with the poor prognosis of CCA. In conclusion, KLK11 is, as a binding protein for CCDC25, possibly involved in the metastatic process of CCA. KLK11 may be used as a prognostic marker for CCA.

Bioinformatic Prediction of Signaling Pathways for Apurinic/Apyrimidinic Endodeoxyribonuclease 1 (APEX1) and Its Role in Cholangiocarcinoma Cells

Apurinic/apyrimidinic endodeoxyribonuclease 1 (APEX1) is involved in the DNA damage repair pathways and associates with the metastasis of several human cancers. However, the signaling pathway of APEX1 in cholangiocarcinoma (CCA) has never been reported. In this study, to predict the signaling pathways of APEX1 and related proteins and their functions, the effects of APEX1 gene silencing on APEX1 and related protein expression in CCA cell lines were investigated using mass spectrometry and bioinformatics tools. Bioinformatic analyses predicted that APEX1 might interact with cell division cycle 42 (CDC42) and son of sevenless homolog 1 (SOS1), which are involved in tumor metastasis. RNA and protein expression levels of APEX1 and its related proteins, retrieved from the Gene Expression Profiling Interactive Analysis (GEPIA) and the Human Protein Atlas databases, revealed that their expressions were higher in CCA than in the normal group. Moreover, higher levels of APEX1 expression and its related proteins were correlated with shorter survival time. In conclusion, the signaling pathway of APEX1 in metastasis might be mediated via CDC42 and SOS1. Furthermore, expression of APEX1 and related proteins is able to predict poor survival of CCA patients.

Interleukin 25 (IL-25) expression in cholangiocarcinoma

Various cytokines are involved in carcinogenesis and tumor progression. Some tumor cells produce cytokines by themselves. Using secretome analysis, a high expression of APEX-1 was found in cholangiocarcinoma (CCA) cell lines. During this secretome analysis, it was found that CCA cell lines overexpressed some cytokines and related molecules, including interleukin 25 (IL-25). In the present study, we first performed precise secretome analysis on cytokines and related molecules in CCA cell lines and identified that IL-25 was overexpressed in CCA cell lines. Then, using immunohistochemical methods, we investigated the expression of IL-25 in the cancer tissues from 20 CCA patients in Northeast Thailand. Correlation between IL-25 expression levels and patients' clinical parameters were analyzed. The results showed that IL-25 expression was significantly (P<0.0001) higher in cancerous tissues than in the normal bile ducts and in the adjacent tissues. Overexpression of IL-25 protein in CCA tissue was confirmed using western blot analysis. Moreover, IL-25 expression in cancerous tissues was significantly (P<0.0015) higher in CCA patients with metastasis than in CCA patients without metastasis. Survival analysis revealed that a high expression of IL-25 was correlated with shorter survival time of CCA patients (P=0.0260). Aberrant expression of IL-25 in CCA tissue was associated with tumor metastasis and poor prognosis, suggesting that IL-25 is a potential prognostic biomarker. Biological roles of IL-25 in CCA genesis and progression should be explored in future.

Serum Cystatin C as a Potential Marker for Glomerular Filtration Rate in Patients with Cholangiocarcinoma

Background: Cholangiocarcinoma (CCA) is the second most common primary hepatobiliary cancer. These patients have meager prognosis and short-term survival. Precise assessment of glomerular filtration rate is a fundamental aspect of clinical care in cancer patients. Cystatin C has been proposed to be superior to creatinine, a well-known marker of renal function. This study aimed to evaluate cystatin C as a marker of GFR calculation in CCA patients. Materials and Methods: One hundred thirty serum samples from CCA patients and 32 from controls were included in this study. Serum cystatin C was measured using immunoturbidity assay. Estimated glomerular filtration rate was calculated by three equations established by chronic kidney disease epidemiology collaboration (based on creatinine and/or cystatin C). Results: Serum cystatin C in CCA patients was higher than that of controls (p=0.0002). Cystatin C was positively correlated with BUN in CCA group (p=0.019). eGFR based on cystatin C and based on both cystatin C and creatinine in CCA was low with significantly different from those of control (p<0.001). Although there was no difference in eGFR using three equations in control, creatinine based eGFR was high with significantly different from eGFR based on cystatin C and on both creatinine and cystatin C in CCA (P=0.000). Proportion in each eGFR stage by three equations showed a high sensitivity with significantly different in CCA (p<0.05). Conclusion: There was a high sensitivity of cys C with significant difference between creatinine and/or cystatin C based eGFR in CCA patients. It should be taken into consideration of mild changes in eGFR by cystatin C which is important in managing drug dosage for CCA patients.

Serum coiled-coil domain containing 25 protein as a potential screening/diagnostic biomarker for cholangiocarcinoma

Coiled-coil domain containing 25 (CCDC25) was previously reported to be upregulated in cholangiocarcinoma (CCA) tissues compared with adjacent normal tissues. The present study investigated whether serum CCDC25 level may be used as a potential marker for the diagnosis of CCA. Bioinformatics tools were used to reveal that CCDC25 is secreted into plasma/serum via a non-conventional pathway, which secretes proteins independently from the endoplasmic reticulum/golgi complex, but is yet to be fully elucidated. Subsequently, the CCDC25 levels in the sera of patients with CCA (n=141), patients with benign biliary disease (BBD; n=53) and healthy controls (HC; n=72) were measured using a quantitative dot blot assay based on the standard curve created using recombinant CCDC25 protein. The results demonstrated that the serum CCDC25 level in the CCA group (0.28±0.06 ng/µl) was significantly higher compared with that in the BBD (0.15±0.03 ng/µl) or HC (0.0017±0.0008 ng/µl) groups. Serum CCDC25 level provided an improved resolution (P=0.0001) compared with carcinoembryonic antigen (P=0.098) or carbohydrate antigen 19-9 (P=0.271) for the differential diagnosis between BBD and CCA. Receiver operating characteristic curve analysis revealed high sensitivity and specificity of serum CCDC25 level to differentiate between patients with CCA and HC (93.0 and 100%, respectively), and also to differentiate between patients with CCA and patients with BBD (75.0 and 84.0%, respectively). CCDC25 expression was further investigated in 23 CCA tissues, and CCDC25 expression in cancer tissues was moderately correlated with the serum CCDC25 level (r²=0.52, P=0.01). Among patients with CCA, serum CCDC25 level was significantly higher in patients with non-metastatic CCA compared with patients with metastatic CCA. Correspondingly, a higher serum CCDC25 level was associated with a longer overall survival time in patients with CCA. In conclusion, serum CCDC25 level may be a promising screening and diagnostic marker for the differential diagnosis of CCA.

Serum Apurinic/Apyrimidinic Endodeoxyribonuclease 1 (APEX1) Level as a Potential Biomarker of Cholangiocarcinoma

Diagnostic and/or prognostic biomarkers for cholangiocarcinoma (CCA) are still insufficient with poor prognosis of patients. To discover a new CCA biomarker, we constructed our secretome database of three CCA cell lines and one control cholangiocyte cell line using GeLC-MS/MS. We selected candidate proteins by five bioinformatics tools for secretome analysis. The inclusion criteria were as follows: having predicted signal peptide or being predicted as non-classically secreted protein; together with having no transmembrane helix and being previously detected in plasma and having the highest number of signal peptide cleavage sites. Eventually, apurinic/apyrimidinic endodeoxyribonuclease 1 (APEX1) was selected for further analysis. To validate APEX1 as a bio-marker for CCA, serum APEX1 levels of 80, 39, and 40 samples collected from CCA, benign biliary diseases (BBD), and healthy control groups, respectively, were measured using dot blot analysis. The results showed that serum APEX1 level in CCA group was significantly higher than that in BBD or healthy control group. Among CCA patients, serum APEX1 level was significantly higher in patients having metastasis than in those without metastasis. The higher level of serum APEX1 was correlated with the shorter survival time of the patients. Serum APEX1 level might be a diagnostic and prognostic biomarker for CCA.

Serum pyruvate dehydrogenase kinase as a prognostic marker for cholangiocarcinoma

Pyruvate dehydrogenase kinase (PDK) is a Ser/Thr kinase that inactivates mitochondrial pyruvate dehydrogenase and serves a key role in aerobic glycolysis, which is a hallmark of cancer cells. The present study determined the PDK expression in cholangiocarcinoma (CCA) tissues and sera to evaluate their applicability as a biomarker for CCA. Using proteomic analysis, PDK was revealed to be the most overexpressed mitochondrial protein in CCA tissues. Then, the expression of PDK isoforms in CCA tissues was examined in 15 CCA cases by immunohistochemistry. The PDK3 isoform levels in the sera were measured using a dot blot assay for 39 patients with CCA, 20 patients with benign biliary disease and 19 healthy volunteers. The results revealed a 27-fold overexpression of PDK3 in cancerous tissues when compared with adjacent non-cancerous tissues. The immunohistochemical results demonstrated that the PDK1, 2 and 3, but not the PDK4, isoforms were overexpressed in cancerous tissues. When the PDK3 levels in the sera were examined, they were significantly higher in CCA when compared with the BBD and healthy groups. The specificity and sensitivity of PDK3 as a marker for CCA were 97.5 and 33.0%, respectively, and high PDK3 levels in the sera were correlated with a short survival time for CCA. In conclusion, PDK3 can be used as a diagnostic/prognostic marker for CCA.

Diagnostic value of serum bile acid composition patterns and serum glycocholic acid levels in cholangiocarcinoma

Cholangiocarcinoma (CCA) is a cancer of biliary epithelial cell origin, which is prevalent in northeastern Thailand. The majority of patients with CCA are diagnosed at the advanced-stage of the disease. Although the early detection and diagnosis of CCA is critical to improve the prognosis of patients, there are presently no specific tumor markers for CCA. A previous study demonstrated that the total serum bile acid (TSBA) levels of patients with CCA are significantly increased, compared with those of healthy controls. In addition, although statistically insignificant, the TSBA levels in the sera of patients with CCA tended to be increased, as compared with the sera of patients with benign biliary disease (BBD). In the present study, the high performance liquid chromatographic (HPLC) patterns of bile acid composition were compared in the sera of patients with CCA, patients with BBD and normal controls. The results revealed that serum bile acid patterns in patients with CCA varied, compared with those in patients with BBD and normal controls. As hypothesized, glycocholic acid (GCA) levels in the sera of patients with CCA and BBD were high, compared with those in healthy controls. In addition, GCA levels in the sera of patients with CCA tended to be higher, as compared with patients with BBD; however, this result was not statistically significant. Therefore, determination of the bile acid patterns and GCA levels in sera using HPLC is feasible, and may aid the diagnosis of CCA.

High expression of CCDC25 in cholangiocarcinoma tissue samples

Cholangiocarcinoma (CCA) is a malignant transformation of biliary epithelial cells. It is a slow growing tumor, but is also highly metastatic with a poor prognosis. Bile acids are known to transactivate the epidermal growth factor receptor (EGFR) in cholangiocytes and induce cyclooxygenase-2 expression. The protein expression profiles of bile acid-treated CCA cells were studied using a proteomic approach. To elucidate the possible mechanisms involved in the bile acid-mediated enhancement of CCA cell migration, the effects of six bile acids, including cholic, deoxycholic, taurocholic, taurodeoxycholic, glycocholic and glycodeoxycholic acid, on the migration of CCA cells were examined in vitro using wound healing assays. Subsequently, the possible proteins involved in enhanced CCA cell migration were investigated using a proteomic approach. Changes to the protein expression profiles of CCA cells following bile acid treatment was examined using two-dimensional electrophoresis and mass spectrometry. The results demonstrated that cholic and deoxycholic acid significantly enhanced the migration of CCA cells, compared with the treated MMNK-1 control cells. CCA cells had 77 overexpressed protein spots following cholic acid treatment, and 50 protein spots following deoxycholic acid treatment, compared with the treated MMNK-1 control cells. Liquid chromatography tandem-mass spectrometry analysis revealed that coiled-coil domain containing 25 (CCDC25) was significantly overexpressed in cholic acid-treated CCA cells compared with in cholic acid-treated control cells. When the expression levels of CCDC25 were investigated using western blot analysis, CCDC25 was demonstrated to be highly expressed in CCA tissues, but not in the adjacent non-cancerous tissue samples. The identified proteins were further analyzed for protein-chemical interactions using STITCH version 3.1 software. CCDC25 protein was identified to be associated with Son of sevenless homolog 1 and growth factor receptor-bound protein 2, which are involved in EGFR signaling. The results of the present study demonstrated that following cholic acid treatment, CCDC25 is overexpressed in CCA cells, which is associated with significantly enhanced cell migration. This suggests that CCDC25 is a potential therapeutic target for the treatment of patients with CCA.

Total serum bile acid as a potential marker for the diagnosis of cholangiocarcinoma without jaundice

Diagnosis of cholangiocarcinoma (CCA) is difficult when patients do not show jaundice. The aim of this study was to examine the feasibility of using the total serum bile acid (TSBA) level as an aid for the diagnosis of CCA in patients without jaundice. For this purpose, TSBA of the following groups were measured using a Beckman Synchron CX4 clinical chemistry analyzer: 60 cases of CCA with total serum bilirubin ≤2 mg/dL (low total bilirubin group, LTB); 32 cases of CCA with total serum bilirubin >2 mg/dL (high total bilirubin group, HTB); and 115 healthy controls. Liver function parameters such as serum cholesterol, albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were also examined. The results showed that the TSBA of both LTB and HTB groups of the CCA patients were significantly higher than that of the healthy controls. Also, significant correlation was observed between TSBA and total bilirubin levels in the HTB group of CCA patients. However, no such correlation was seen in the LTB group. The cut-off value of TSBA was determined for the LTB group of CCA patients using the receiver operating characteristic curve analysis, and it was 6.05 μmol/L with the sensitivity and specificity of 46.7% and 84.4%, respectively. In addition, the ALP level was correlated well with the TSBA level and ALP in HTB group was significantly higher than that of LTB group. Moreover, the combination of high TSBA and high ALP levels gave higher specificity up to 97.4%. TSBA might be useful for the diagnosis of CCA patients without jaundice.

Serum cathepsin B to cystatin C ratio as a potential marker for the diagnosis of cholangiocarcinoma

Cholangiocarcinoma (CCA) is a cancer of the bile duct epithelial cells. The highest incidence rate of CCA with a poor prognosis and poor response to chemotherapy is found in Southeast Asian countries, especially in northeastern Thailand and Lao PDR. Cathepsin B is a lysosomal cysteine protease which is regulated by cysteine proteinase inhibitors such as cystatin C. Elevation of cathepsin B levels in biological fluid has been observed in patients with inflammatory diseases and many cancers. We aimed to investigate the serum cathepsin B and cystatin C levels of CCA patients to evaluate the feasibility of using cathepsin B and cystatin C as markers for the diagnosis of CCA. Fifty-six sera from CCA patients, 17 with benign biliary diseases (BBD) and 13 from controls were collected and the cathepsin B and cystatin C levels were determined. In addition, cathepsin B expression was investigated immunohistochemically for 9 matched-pairs of cancerous and adjacent tissues of CCA patients. Serum cathepsin B, but not cystatin C, was significantly higher in CCA and BBD patient groups compared to that in the control group. Consistently, all cancerous tissues strongly expressed cathepsin B while adjacent tissues were negative in 7 out of 9 cases. In contrast, serum cystatin C levels were comparable between CCA and control groups, although serum cystatin C levels in the BBD group was higher than that in the control or CCA groups. When the serum cathepsin B to cystatin C ratio was calculated, that of the CCA group was significantly higher than that of the control group, and, although statistically not significant, the ratio of CCA group showed a trend to be higher than that of the BBD group. Thus, the cathepsin B to cystatin C ratio might be used as an alternative marker for aiding diagnosis of CCA.

Serum adhesion molecule-1 (ICAM-1) as a potential prognostic marker for cholangiocarcinoma patients

Cholangiocarcinoma (CCA) is a malignancy of bile ducts with a high incidence of invasion and metastasis. This disease is often detected in advanced stages because of the difficulties of early diagnosis, leading to a high mortality rate. However, biomarkers for early CCA detection are still lacking. In this study, to identify potential biomarker proteins, differential secretome analysis by the GeLC-MS/MS approach was applied with four CCA cell lines and a control immortalized cholangiocyte cell line. Among 78 up-regulated proteins, 53 including ICAM- 1 were exclusively expressed in four CCA secretomes but not in MMNK1. Based on this result, we measured ICAM-1 levels in serum samples of CCA patients and healthy controls and found significantly higher values in CCA patients' sera. Receiver operating characteristic curve analysis suggested that serum ICAM-1 level could be a discriminatory diagnostic marker for CCA and healthy controls (area under curve=0.829) with a sensitivity of 77% and a specificity of 70% at a cut off value of 167 ng/ml. Moreover, the serum ICAM-1 showed positive correlations with alkaline phosphatase and carcinoembryonic antigen levels. Comparison of ICAM-1 levels of paired pre- and post-operative sera of 12 cases revealed significant decrease after tumor resection. However, serum ICAM-1 levels were not significantly different between CCA and benign biliary diseases with mainly inflammatory features.

Tn5-OT182 should not be used to identify genes involved in biofilm formation in Burkholderia pseudomallei

Burkholderia pseudomallei, a gram-negative bacterium, is the causative agent of melioidosis. One of the important virulence properties of this bacteria is its ability to form a biofilm. Genes involved in biofilm formation in B. pseudomallei have not been thoroughly studied. In this study, Tn5-OT182 mutagenesis was used to isolate of B. pseudomallei strain A2 mutants unable to produce biofilm. Ten biofilm-defective transposon mutants were isolated and analyzed. Flanking DNA from each transposon mutant were self-cloned and sequenced, then the sequences were analyzed with the BLAST program. To confirm these genes are involved in biofilm formation, we constructed three gene deletion mutants marked with a tetracycline resistance gene. The constructed tet(r)-marked deletion mutants were checked for correct structure and size by polymerase chain reaction. When subjected to biofilm assay, all tested tet(r)-marked deletion mutants were still able to produce biofilm, indicating the three genes are not involved in biofilm formation. These results suggest integration of Tn5-OT182 in genes not involved in biofilm production can render B. pseudomallei unable to produce biofilm by an unknown mechanism. This information demonstrates Tn5-OT182 is not a reliable tool for identifying genes involved in biofilm formation unless a confirmatory experiment is carried out in parallel.

Construction and characterization of an unmarked aroC deletion mutant of Burkholderia pseudomallei strain A2

Using a sucrose counter-selection strategy, we have constructed an unmarked aroC deletion mutant of B. pseudomallei strain A2 in order to investigate the possibility of an effective live-attenuated vaccine. The aroC deletion in the resultant mutant, designated A2DeltaaroC, was confirmed by PCR, Southern hybridization and failure of the mutant to grow in a defined medium without aromatic compounds. Compared to the parental wild type strain, A2DeltaaroC was highly attenuated for virulence following intraperitoneal introduction into BALB/c and C57BL/6 mice. BALB/c mice immunized intraperitoneally with A2DeltaaroC were not protected against a challenge dose of 500 cfu (25 x LD50) of the parental strain A2, whereas C57BL/6 mice similarly immunized intraperitoneally with A2DeltaaroC were significantly protected against a challenge dose of 6,000 cfu (20 x LD50).

Virulence of Burkholderia pseudomallei does not correlate with biofilm formation

Burkholderia pseudomallei is the causative agent of melioidosis but currently the pathogenesis of the disease is still poorly understood. One of the virulent factors of gram-negative bacteria is the ability to produce biofilm to evade host defense. As B. pseudomallei has also been reported to develop the biofilm [1], in the present study, we therefore, quantified the biofilm formation in 50 strains of B. pseudomallei and compared with 50 strains of its avirulent counterpart Burkholderia thailandensis using a modified microtiter-plate test. The results showed that the quantity of biofilm produced by B. pseudomallei was statistically higher (P< 0.01) than that of B. thailandensis (means and SEs of the corrected OD630 were 2.17+/-0.29 and 0.59+/-0.05, respectively). Transmission electron micrographs of the B. pseudomallei strain with high biofilm formation exhibited microcolonies of bacterial cells surrounded by dense extracellular slime matrix comparing with only trace quantity in the low biofilm-producing strain or the biofilm mutants generated by Tn5-OT182 mutagenesis. However, no correlation could be observed between the biofilm formation and virulence, judging from the LD50 values in BALB/c mice. The data obtained with these naturally occurring Burkholderia species and the biofilm mutants are incompatible with the possibility that the biofilm plays a role in the pathogenesis of B. pseudomallei infection.

Site-specific regulation of tissue dendritic cell function by granulocyte-macrophage colony-stimulating-factor

Tissue dendritic cells (DC) are usually associated with phagocytic function but poor T-cell immunostimulatory capacity. Following activation, dendritic cells are stimulated to leave tissue sites and migrate to lymphoid tissue, acquiring immunostimulatory capacity during the process. We provide evidence that the immunostimulatory capacity of tissue DC, but not spleen cells, can be affected in situ by granulocyte-macrophage colony-stimulating-factor (GM-CSF). Initially it was found that islet cells from non-obese diabetic and BALB/c mice, which produce GM-CSF, showed significantly higher immunostimulatory capacity than islets from C3H and C57BL/6 mice, which do not produce GM-CSF. Second, pretreatment of nonobese diabetic mice with anti-GM-CSF antibody significantly reduced the immunostimulatory capacity of islet cells, but not spleen cells, although it had no effect on the numbers of cells expressing DC-associated antigens. Therefore the immunostimulatory function of islet DC is partially dependent on GM-CSF. By contrast, spleen DC immunostimulatory function does not show the same dependence on GM-CSF. This may affect the ability of dendritic cells to stimulate autoimmune responses or tolerance.