Periostin is associated with prognosis and immune cell infiltration in pancreatic adenocarcinoma based on integrated bioinformatics analysis

BACKGROUND

Pancreatic cancer is one of the most aggressive human malignancies. Previous research has shown that periostin (POSTN) promotes pancreatic cancer cell proliferation, migration, and invasion. Further, POSTN is involved in tumor microenvironment remodeling during tumor progression. However, the relationship between POSTN expression, immune cell infiltration, and the efficacy of immunotherapy in pancreatic cancer is unclear.

METHODS

We conducted a comprehensive evaluation of POSTN differential expression, examining mRNA and protein levels. To gather data, we utilized various databases including gene expression profiling interactive analysis 2 (GEPIA2), gene expression omnibus (GEO), and the human protein atlas (HPA). To investigate the correlation between POSTN expression and clinical characteristics, we analyzed data from the Kaplan-Meier plotter database and clinical data sourced from the cancer genome atlas (TCGA). Furthermore, we performed gene ontology (GO) analysis, Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis, and gene set enrichment analysis (GSEA). Additionally, we explored the relationship between POSTN expression and immune cell infiltration, as well as the immunophenoscore (IPS), by leveraging the cancer immunome atlas (TCIA) database. Lastly, we examined the tumor mutational burden (TMB) in pancreatic cancer in relation to POSTN expression.

RESULTS

When compared with healthy pancreatic tissues, pancreatic cancer tissues displayed significantly higher levels of POSTN, which was indicative of a worse prognosis. POSTN expression was closely associated with extracellular matrix (ECM) organization, ECM-receptor interaction, and focal adhesion by GO, KEGG pathway, and GSEA analyses. Higher expression of POSTN was associated with increased infiltration of M2 macrophages. Additionally, increased IPS was linked to lower POSTN expression. IPS scores for CTLA4, PD-1/PDL1, and CTLA4/PD-1/PDL1 immune checkpoint inhibitors were also higher in the POSTN-low expression group, suggesting that lower expression of POSTN is associated with a better outcome with checkpoint inhibitor treatment.

CONCLUSION

POSTN is related to pancreatic cancer prognosis, and may influence immune cell infiltration. High expression of POSTN is predicted to correlate with lower sensitivity to immunotherapy with checkpoint inhibitors in pancreatic cancer.

Influence of Ascorbic Acid as a Growth and Differentiation Factor on Dental Stem Cells Used in Regenerative Endodontic Therapies

BACKGROUND

Vitamin C is one of the major extracellular nonenzymatic antioxidants involved in the biosynthesis of collagen. It promotes the growth of fibroblasts, wound healing processes, and enhances the survival and differentiation of osteoblasts. The potential effects of ascorbic acid on human dental pulp cells (DPC) and the cells of the apical papilla (CAP) used in actual regenerative endodontic procedures remain largely unknown. In this study, we investigated the possible employment of ascorbic acid in the differentiation and regenerative therapies of DPC and CAP.

METHODS

Nine extracted human wisdom teeth were selected for this study. Subpopulations of stem cells within DPC and CAP were sorted with the mesenchymal stem cell marker STRO-1, followed by treatments with different concentrations (0 mM, 0.1 mM, 0.5 mM, and 1.0 mM) of ascorbic acid (AA), RT-PCR, and Western blot analysis.

RESULTS

FACS analysis revealed the presence of cell subpopulations characterized by a strong expression of mesenchymal stem cell marker STRO-1 and dental stem cell markers CD105, CD44, CD146, CD90, and CD29. Treatment of the cells with defined amounts of AA revealed a markedly increased expression of proliferation marker Ki-67, especially in the concentration range between 0.1 mM and 0.5 mM. Further investigations demonstrated that treatment with AA led to significantly increased expression of common stem cell markers OCT4, Nanog, and Sox2. The most potent proliferative and expressional effects of AA were observed in the concentration of 0.1 mM.

CONCLUSIONS

AA might be a novel and potent growth promoter of human dental cells. Increasing the properties of human dental pulp cells and the cells of the apical papilla using AA could be a useful factor for further clinical developments of regenerative endodontic procedures.

Angiogenetic transcriptional profiling reveals potential targets modulated in blood of patients with cardiovascular disorders

OBJECTIVES

Based on the angiogenetic, transcriptional profile of non-diseased and arteriosclerotic vessels, we aim to identify the leucocytic markers as a potential, minimal invasive tool supporting diagnosis of vascular pathology.

METHODS

Transcriptional profiling was performed with Angiogenesis RT² Profiler PCR (Polymerase Chain Reaction) array on three non-pathological and three arteriosclerotic vessels, followed by immunohistochemical staining. Based on these screening results, selected transcripts were employed for qPCR with specific primers and investigated on the blood RNA (RiboNucleic Acid) obtained from nine healthy controls and 29 patients with cardiovascular disorders. Thereafter, expression of these transcripts was investigated in vitro in human monocytes under calcification-mimicking conditions.

RESULTS AND CONCLUSIONS

Transcriptional profiling on the vessels revealed that out of 84 targets investigated two were up-regulated more than 100-fold, 18 more than 30 and 15 more than 10, while the most noticeable down-regulation was observed by ephrin-A3 and platelet-derived growth factor alpha (PDGFA) genes. Based on the vessel results, investigations of the selected blood transcripts revealed that thrombospondin 1 (THBS1), thrombospondin 3 (THBS3), transforming growth factor, beta receptor 1 (TGFBR1), platelet-derived growth factor alpha, plasminogen activator, urokinase (PLAU) and platelet/endothelial cell adhesion molecule 1 (PECAM-1) were significantly elevated in cardiovascular blood as compared to corresponding controls. Induction of calcification-related conditions in vitro to human THP-1 monocytes led to noticeable modulation of these transcripts. Taken together, these data demonstrate that leucocytic THBS1, THBS3, TGFBR1, platelet-derived growth factor alpha, PLAU and PECAM-1 have a correlation with cardiovascular disorders and could be used as a supportive tool predicting development of this pathological condition.

Analysis of genomic alterations in cancer associated human pancreatic stellate cells

Pancreatic stellate cells (PSCs) constitute important cells of the pancreatic microenvironment and their close interaction with cancer cells is important in pancreatic cancer. It is currently not known whether PSCs accumulate genetic alterations that contribute to tumor biology. Our aim was to analyze genetic alterations in cancer associated PSCs. PSC DNA was matched to DNA isolated from pancreatic cancer patients’ blood (n = 5) and analyzed by Next-Generation Sequencing (NGS). Bioinformatic analysis was performed using the GATK software and pathogenicity prediction scores. Sanger sequencing was carried out to verify specific genetic alterations in a larger panel of PSCs (n = 50). NGS and GATK analysis identified on average 26 single nucleotide variants in PSC DNA as compared to the matched blood DNA that could be visualized with the Integrative Genomics Viewer. The absence of PDAC driver mutations (KRAS, p53, p16/INK4a, SMAD4) confirmed that PSC isolations were not contaminated with cancer cells. After filtering the variants, using different pathogenicity scores, ten genes were identified (SERPINB2, CNTNAP4, DENND4B, DPP4, FGFBP2, MIGA2, POLE, SNRNP40, TOP2B, and ZDHHC18) in single samples and confirmed by Sanger sequencing. As a proof of concept, functional analysis using control and SERPINB2 knock-out fibroblasts revealed functional effects on growth, migration, and collagen contraction. In conclusion, PSC DNA exhibit a substantial amount of single nucleotide variants that might have functional effects potentially contributing to tumor aggressiveness.

Pyroptosis: A Common Feature of Immune Cells of Haemodialysis Patients

NLRP-3 inflammasome activation can result in interleukin-1β (IL-1β) release and inflammatory cell death (pyroptosis). Caspase-1 is able to trigger both processes. However, other caspases, caspase-4, -5 and -8, are believed to initiate pyroptosis without affecting IL-1 secretion. In this study, we evaluated two cardiovascular risk groups, haemodialysis patients (HD) and patients with intact kidney function but high blood pressure (BP), to analyse the mechanisms driving pyroptosis. Twenty HD were age-, gender- and diabetes-matched to BP. We found a common pyroptotic pattern in both patient groups, at which pyroptosis rates but not IL-1 β levels were significantly higher in monocytes (HD vs. BP: p < 0.05), granulocytes (p < 0.01) and lymphocytes (p < 0.01) of HD patients. As uremic toxins are drivers of inflammation and regulated cell death, we applied a monocyte- and macrophage-like THP-1 model system to demonstrate that the protein-bound uremic toxin indoxyl sulfate (IS) is an inducer of pyroptotic cell death, particularly engaging caspase-4/caspase-5 and to a lesser extent caspase-8 and caspase-1. These data suggest that the uremic toxin IS can mediate pyroptosis in HD patients and the inflammatory caspase-4 and/or caspase-5 contribute to pyroptosis rates to a higher extent in comparison to caspase-1.

Serum Testosterone Levels Are Not Modified by Vitamin D Supplementation in Dialysis Patients and Healthy Subjects

INTRODUCTION

Low serum testosterone is related to increased mortality in male dialysis patients. An association of vitamin D status with serum androgen levels with concordant seasonal variation has been described, but it is undecided whether vitamin D supplementation improves testosterone levels.

METHODS

In a randomized, placebo-controlled, and double-blind manner, we investigated the effects of an oral vitamin D supplementation in healthy subjects and hemodialysis patients on testosterone levels. One hundred three healthy individuals received cholecalciferol 800 IE/day (n = 52) or placebo (n = 51) for 12 weeks. Thirty-three hemodialysis patients received cholecalciferol adapted to their serum levels following current guidelines (n = 15) or placebo (n = 18) for 12 weeks.

RESULTS

In healthy individuals, 25(OH)D3 levels rose significantly in the verum group (38.1 ± 13.7 vs. 72.5 ± 15.4 nmol/L, p < 0.001), whereas in the placebo group, levels dropped (37.7 ± 14.7 vs. 31.9 ± 13.1, p < 0.001). Testosterone levels did not change significantly (verum, males: 20.9 ± 6.6 vs. 20.5 ± 7.9 nmol/L, p = 0.6; verum, females: 0.9 ± 0.5 vs. 0.92 ± 0.5, p = 0.4; placebo, males: 18.5 ± 10.2 vs. 21.8 ± 16.5, p = 0.07, placebo, females: 1.6 ± 4.2 vs. 1.6 ± 4.9, p = 0.6). In dialysis patients, the mean cholecalciferol level was only 32.3 ± 17.8 nmol/L, with only 2% of the values being within the normal range. Cholecalciferol levels normalized in the verum group (29.4 ± 11.2 vs. 87.8 ± 22.3, p < 0.001), whereas levels dropped further in the placebo group (33.6 ± 16.6 vs. 24.6 ± 8.0 nmol/L, p < 0.001). Testosterone levels did not change significantly (verum, males: 8.0 ± 3.7 vs. 7.8 ± 3.8, p = 0.8; verum, females: 1.3 ± 1.0 vs. 1.2 ± 1.0 nmol/L, p = 0.5; placebo, males: 11.9 ± 5.0 vs. 11.6 ± 4.0 nmol/L, p = 0.6; placebo, females: 0.8 ± 0.5 vs. 0.7 ± 0.4 nmol/L, p = 0.8).

CONCLUSION

Serum testosterone levels in hemodialysis patients and healthy individuals are independent from vitamin D status and cannot be significantly increased by cholecalciferol supplementation.

Uremic Apelin and Leucocytic Angiotensin-Converting Enzyme 2 in CKD Patients

Apelin peptides (APLN) serve as second substrates for angiotensin-converting enzyme 2 (ACE2) and, in contrast to angiotensin II (AngII), exert blood-pressure lowering and vasodilatation effects through binding to G-coupled APLN receptor (APLNR). ACE2-mediated cleavage of the APLN may reduce its vasodilatory effects, but decreased ACE2 may potentiate the hypotensive properties of APLN. The role of APLN in uremia is unclear. We investigated the correlations between serum-APLN, leucocytic APLNR, and ACE2 in 32 healthy controls (NP), 66 HD, and 24 CKD3-5 patients, and the impact of APLN peptides on monocytic behavior and ACE2 expression under uremic conditions in vitro. We observed that serum APLN and leucocytic APLNR or SLCO2B1 were significantly elevated in uremic patients and correlated with decreased ACE2 on uremic leucocytes. APLN-treated THP-1 monocytes revealed significantly increased APLNR and ACE2, and reduced TNFa, IL-6, and MCSF. Uremic toxins induced a dramatic increase of miR-421 followed by significant reduction of ACE2 transcripts, partially counteracted with APLN-13 and -36. APLN-36 triggered the most potent transmigration and reduction of endothelial adhesion. These results suggest that although APLN peptides may partly protect against the decay of monocytic ACE2 transcripts, uremic milieu is the most dominant modulator of local ACE2, and likely to contribute to the progression of atherosclerosis.

No significant relation of proinflammatory slanDCs with uremic pruritus

The pathogenesis of the pruritus associated with chronic kidney disease-(CKD-aP) is not completely understood. Endocrine, metabolic, neuropathic, and inflammatory disorders were suspected to be the origin of CKD-aP. Based on the hypothesis which suggests that deregulated systemic inflammation may play a crucial role in CKD-a, we investigated the potential relation of an inflammatory monocyte subset (slanDCs) with CKD-aP. Itch questionnaire, visual analogue scale (VAS)-scoring, and Dermatology Life Quality Index (DQLI) were applied for the characterization of itch sensation. VAS-scoring was re-evaluated after 6 months. Monocytes were flow-cytometrically categorized into classical, intermediate, and non-classical subsets. slanDCs are part of the non-classical monocyte subpopulation. Sixty-six hemodialysis patients (CKD5-D) were screened of whom 43 met the study inclusion criteria. In all, 46.5% of patients were scored pruritus-positive (CKD-aP+). CKD-aP severity level of patients was moderate at the start of the study (VAS 5.3 ± 2.5) and remained unchanged after 6 months (VAS: 5.2 ± 1.9, P < 0.757). Thirty percent of patients were affected with mild, 30.0% with moderate, and 35.0% with severe itchiness. In contrast to all other factors tested solely slanDC showed a weak correlation to VAS-score (r = 0.41, P = 0.07). slanDC frequencies between CKD5-D patients with and without itch sensation, however, were not significantly different. Endocrine problems appeared to influence CKD-aP. CKD-aP + patients had significantly higher L-thyroxin supplementation than CKD-aP- (50.0% vs 8.7%, P < 0.005). A binary logistic regression model confirmed the significance of L-thyroxin medication on chronic itch problems of our CKD5-D patients ( P < 0.007). There is no clear evidence that slanDCs are related to uremic pruritus. Therefore, other factors underlie the pathophysiology of CKD-aP.

Monocytes in Uremia

Monocytes play an important role in both innate immunity and antigen presentation for specific cellular immune defense. In patients with chronic renal failure, as well as those treated with maintenance hemodialysis, these cells are largely dysregulated. There is a large body of literature on monocyte alterations in such patients. However, most of the publications report on small series, there is a vast spectrum of different methods and the heterogeneity of the data prevents any meta-analytic approach. Thus, a narrative review was performed to describe the current knowledge. Monocytes from patients with chronic renal failure differ from those of healthy individuals in the pattern of surface molecule expression, cytokine and mediator production, and function. If these findings can be summarized at all, they might be subsumed as showing chronic inflammation in resting cells together with limited activation upon immunologic challenge. The picture is complicated by the fact that monocytes fall into morphologically and functionally different populations and population shifts interact heavily with dysregulation of the individual cells. Severe complications of chronic renal failure such as impaired immune defense, inflammation, and atherosclerosis can be related to several aspects of monocyte dysfunction. Therefore, this review aims to provide an overview about the impairment and activation of monocytes by uremia and the resulting clinical consequences for renal failure patients.

Angiotensin converting enzymes ACE and ACE2 in thyroid cancer progression

Angiotensin-converting enzymes, ACE and ACE2, play not only a pivotal role in the regulation of blood pressure, but are involved in the processes of pathophysiology, including thyroid dysfunction or progression of several neoplasia such as cancers of skin, lungs, pancreas and leukemia. However, their role in the thyroid carcinogenesis remains unknown. We examined in this study the expression of ACE and ACE2 in thyroid tissues and their possible employment as biomarkers for thyroid cancer progression. Thyroid tissues, including 14 goiters (G), 12 follicular adenomas (FA), 10 follicular thyroid carcinomas (FTC), 14 papillary thyroid carcinomas (PTC) and 11 undifferentiated thyroid carcinomas (UTC), were subjected to RT-PCR and protein analyses with primers or antibodies specific for ACE and ACE2, respectively. FA revealed significantly increased ACE compared to other groups and FTC was significantly higher than UTC. ACE2 was significantly increased in PTC in comparison to G, FA and UTC, and in FTC as compared to G. The ratio ACE/ACE2 decreased, while ACE2/ACE increased with the differentiation grade of thyroid carcinoma. ACE was significantly diminished in individuals older than 50. Both ACEs were significantly diminished in M1 patients, ACE2 additionally in higher tumor masses. ACE and ACE2 are regulated within thyroid benign and malignant tissues. As the transcript ratio between both enzymes correlate proportional with the differentiation status of thyroid cancer, ACE and ACE2 may serve as new markers for thyroid carcinoma.

Expression of ARE-binding proteins AUF1 and HuR in follicular adenoma and carcinoma of thyroid gland

Both adenylate-uridylate rich elements binding proteins AUF1 and HuR may participate in thyroid carcinoma progression. In this study we investigated the expression of both factors on a protein level with a special focus on follicular adenoma and follicular thyroid carcinoma. By employment of immunofluorescence and western blot on 68 thyroid tissues including 7 goiter, 16 follicular adenoma (4 adenomatous hyperplasia), 19 follicular thyroid carcinomas, 13 papillary thyroid carcinomas and 14 undifferentiated thyroid carcinomas we investigated protein expression of AUF1 and HuR. In addition to previous results we demonstrated that AUF1 and HuR are significantly up-regulated in carcinoma tissues as compared with follicular adenoma or goiter tissues. Furthermore, by evaluation of AUF1 or HuR expression, or combination of both proteins on total tissue lysates, we were able to demonstrate a significant difference between follicular adenoma and follicular thyroid carcinoma. Overexpression of AUF1 and HuR is a common finding observed in thyroid malignancy. Analysis of the tissues obtained by surgical resection as demonstrated in this study is comparable to a fine needle aspiration and in combination with AUF1/HuR immuno-analysis may support the conventional immunohistological investigations. The promising results of this study were performed on relatively small collective, but justify future development of a quick thyroid diagnostic test on larger cohort of the patients, especially for thyroid samples which are inadequate for histological examinations.

Modulation of leucocytic angiotensin-converting enzymes expression in patients maintained on high-permeable haemodialysis

Background

High mortality of haemodialysis patients is associated with systemic chronic inflammation and overactivation of the renin-angiotensin system (RAS). Insufficient elimination of pro-inflammatory immune mediators, especially in the molecular weight range of 15-45 kDa, may be one of the reasons for this. Employment of haemodialysis membranes with increased permeability was shown to ameliorate the inflammatory response and might modulate the effects of local RAS. In this study, we tested the impact of high cut-off (HCO), medium cut-off (MCO) and high-flux (HF) dialysis on leucocytic transcripts of angiotensin-converting enzymes (ACE and ACE2). Additionally, the impact of HCO, MCO and HF sera and dialysates on local ACEs and inflammation markers was tested in THP-1 monocytes.

Methods

Patients' leucocytes were obtained from our recent clinical studies comparing HCO and MCO dialysers with HF. The cells were subjected to quantitaive polymerase chain reaction (qPCR) analyses with TaqMan probes specific for ACE, ACE2 and angiotensin II (AngII) and Ang1-7 receptors. Sera and dialysates from the clinical trials as well as samples from in vitro dialysis were tested on THP-1 monocytic cells. The cells were subjected to qPCR analyses with TaqMan probes specific for ACE, ACE2, interleukin-6 and tumour necrosis factor α and immunocytochemistry with ACE and ACE2 antibodies.

Results

Leucocytes obtained from patients treated with HCO or MCO demonstrated decreased transcript expression of ACE, while ACE2 was significantly upregulated as compared with HF. Receptors for AngII and Ang1-7 remained unchanged. THP-1 monocytes preconditioned with HCO and MCO patients' or in vitro dialysis sera reflected the same expressional regulation of ACE and ACE2 as those observed in HCO and MCO leucocytes. As a complementary finding, treatment with HCO and MCO in vitro dialysates induced a pro-inflammatory response of the cells as demonstrated by elevated messenger RNA expression of tumour necrosis factor α and interleukin-6, as well as upregulation of ACE and decreased levels of ACE2.

Conclusions

Taken together, these data demonstrate that employment of membranes with high permeability eliminates a spectrum of mediators from circulation that affect the RAS components in leucocytes, especially ACE/ACE2.

Circulating miR-421 Targeting Leucocytic Angiotensin Converting Enzyme 2 Is Elevated in Patients with Chronic Kidney Disease

BACKGROUND

Decreased levels of leucocytic angiotensin converting enzyme 2 (ACE2) relate to atherosclerosis in patients with chronic kidney disease (CKD). Recently, micro RNA 421 (miR-421) was found to target and down-regulate ACE2 in human cardiac myofibroblasts. In this study, we investigated the correlation between serum levels of miR-421 and ACE2 transcripts in circulating leukocytes of healthy individuals (NP), CKD (3-5) and haemodialysis (HD) patients. Furthermore, we tested the possible interaction between miR-421 and 3'-UTR of ACE2 under normal and uremic milieu.

METHODS

The levels of circulating miR-421, serum Ang1-7 and expression of leucocytic ACE2, ACE, MASR, AT1R and AT2R were investigated in 16 CKD3-5 (76 ± 10 years), 32 HD patients (65 ± 13 years) and 23 NP (51 ± 5 years) by employment of specific primers, TaqMan and competitive enzyme-linked immunosorbent assay assays. Interaction between miR-421 and ACE2-3'-UTR was investigated on THP-1 cells by employment of normal and uremic sera, reporter vectors and miR-421 inhibitor. Effects of uremic toxins indoxyl sulphate, p-cresol and p-cresyl sulphate on ACE2 and miR-421 levels were investigated in THP-1 monocytes.

RESULTS

The levels of serum miR-421 were significantly elevated, while Ang1-7 was significantly decreased in CKD3-5 and HD patients as compared with NP. Serum Ang1-7 correlated positively with leucocytic ACE2 (r2 = 0.213, p < 0.001). We found a significant and inverse correlation between the levels of circulating miR-421 and the expression of leucocytic ACE2 (r2 = 0.223, p < 0.0001). Further significant and positive correlations could be demonstrated between miR-421 and the transcripts of leucocytic AT1R (r2 = 0.094, p < 0.05) or eGFR (r2 = 0.231, p < 0.0001) or CRP (r2 = 0.092, p < 0.01). We found no correlations between miR-421 and ACE or AT2R or MASR expression. Treatment with miR-421 or uremic serum led to noticeable decrease of reporter 3'UTR-ACE2. Anti-miR-421 treatment resulted in the up-regulation of ACE2 protein. All uremic toxins tested were able to significantly elevate miR-421 levels and decrease the monocytic ACE2 transcripts.

CONCLUSIONS

Uremic patients show an enhanced expression of serum miR-421 as compared to healthy individuals. A strong association of circulating miR-421 with decreased transcripts of ACE2 may contribute to the low expression of the enzyme in leukocytes of CKD patients, further supporting the development of atherosclerotic events.

Monocytic angiotensin-converting enzyme 2 relates to atherosclerosis in patients with chronic kidney disease

Background: Increased levels of monocytic angiotensin-converting enzyme (ACE) found in haemodialysis (HD) patients may directly participate in the pathogenesis of atherosclerosis. We demonstrated recently that uremia triggers the development of highly pro-atherogenic monocytes via an angiotensin II (AngII)–dependent mechanism. Opposing actions of the AngII-degrading ACE2 remain largely unknown. We examined the status of both ACEs and related receptors in circulating leukocytes of HD, not-dialyzed CKD and healthy individuals. Furthermore, we tested the possible impact of monocytic ACEs on atherogenesis and behaviour of the cells under conditions mimicking chronic renal failure.

Methods: Expression of ACE, ACE2, AT1R, AT2R and MASR was investigated on circulating leukocytes from 71 HD (62 ± 14 years), 24 CKD stage 3–5 (74 ± 10 years) patients and 37 healthy control subjects (53 ± 6 years) and isolated healthy monocytes treated with normal and uremic serum. Analyses of ACE, ACE2, ICAM-1, VCAM-1, MCSF and endothelial adhesion were tested on ACE-overexpressing THP-1 monocytes treated with captopril or losartan. ACE2-overexpressing monocytes were subjected to transmigration and adhesion assays and investigated for MCP-1, ICAM-1, VCAM-1, MCSF, AT1R and AT2R expression.

Results: The ACE mRNA level was significantly increased in HD and CKD stage 3–5 leukocytes. Correspondingly, ACE2 was downregulated and AngII as well as MAS receptor expression was upregulated in these cells. Healthy monocytes preconditioned with uremic serum reflected the same expressional regulation of ACE/ACE2, MAS and AngII receptors as those observed in HD and CKD stage 3–5 leukocytes. Overexpression of monocytic ACE dramatically decreased levels of ACE2 and induced a pro-atherogenic phenotype, partly reversed by AngII-modifying treatments, leading to an increase in ACE2. Overexpression of ACE2 in monocytes led to reduced endothelial adhesion, transmigration and downregulation of adhesion-related molecules.

Conclusions: HD and not-dialyzed CKD stage 3–5 patients show enhanced ACE and decreased ACE2 expression on monocytes. This constellation renders the cells endothelial adhesive and likely supports the development of atherosclerosis.

Differential Expression of Lipoprotein-Associated Phospholipase A2 in Monocyte Subsets: Impact of Uremia and Atherosclerosis

BACKGROUND

Monocytic products, such as lipoprotein-associated phospholipase A2 (Lp-PLA2), may participate in the development of atherosclerosis. Heterogeneity of monocytes is widely acknowledged. Classical, intermediate, and non-classical subsets can be discerned. Recently, an inflammatory, pro-atherogenic monocyte population could be identified in hemodialysis patients. In this study, we investigated the expression of Lp-PLA2 on leucocytes and different monocyte subpopulations and their possible role in uremia, inflammation, and atherosclerosis.

METHODS

Chronic kidney disease stage 5-D (CKD5-D; n = 57), healthy control subjects with hs-C-reactive protein (CRP) levels ≤1 mg/L (CO-N, n = 22) and a control group with inflammatory activation (CRP levels >1 mg/L, CO-I, n = 29) were enrolled in this cross-sectional observation. The CKD5-D cohort was dichotomized into patients with (A+) and without subclinical atherosclerosis (A-) by carotid artery ultrasound measurement. Lp-PLA2 activity was determined in plasma samples, Lp-PLA2 mRNA expression analysis in leucocytes, and sorted monocyte subsets. Effects of Lp-PLA2 overexpression were studied in classical vs. intermediate and non-classical subsets.

RESULTS

The classical monocytes expressed the highest Lp-PLA2 mRNA levels as compared to other subpopulations. CKD5-D patients revealed significantly higher Lp-PLA2 transcripts, as well as higher Lp-PLA2 plasma activity as compared to healthy and "inflammatory" controls. In vitro data confirmed that uremia significantly contributes to Lp-PLA2 mRNA upregulation. Non-classical monocytes of A+ patients revealed significant higher Lp-PLA2 mRNA compared to A-.

CONCLUSION

Uremic environment but not inflammation per se increases plasma Lp-PLA2 activity and upregulates monocytic Lp-PLA2 mRNA expression. The highest Lp-PLA2 levels were found in the classical and not in the inflammatory subsets. Atherosclerosis also contributes to a subset-specific increase in Lp-PLA2 mRNA expression.

CD97 promotion of gastric carcinoma lymphatic metastasis is exosome dependent

BACKGROUND

CD97 knockdown impairs the metastatic capacity of SGC-7901 gastric cancer cells. However, the role of CD97 in the distant lymphatic premetastatic niche formation of gastric cancer remains unknown.

METHODS

Exosomes and the soluble fraction were isolated from SGC-L (an SGC-7901-cell-derived highly lymphatic metastatic cell line) and CD97-knockdown (SGC-L/CD97-kd) cells, and were co-cultured with gastric cancer cells. The metastatic capacity of the two cell lines was evaluated in vitro and in a footpad lymph node metastasis mouse model. Premetastatic-niche-formation-related proteins were examined immunohistochemically.

RESULTS

CD97 expression was ninefold higher in SGC-L cells than in SGC-7901 cells. In vitro, exosomes or conditioned medium from the SGC-L cells enhanced cell proliferation (20 % increase) and invasion (30 % increase) as compared with that from SGC-L/CD97-kd cells (p < 0.01). Intrafootpad injections of SGC-L, but not SGC-L/CD97-kd exosomes or conditioned medium, strongly promoted SGC-L and SGC-L/CD97-kd cell accumulation in the draining lymph nodes (p < 0.01) and increased CD55, CD44v6, α5β1, CD31, epithelial cell adhesion molecule, and CD151 expression. Although the SGC-L/CD97-kd exosomes alone were insufficient for promotion of metastasis, they were partly aided by the SGC-L-cell-derived soluble fraction.

CONCLUSIONS

The CD97 small isoform promotes SGC-L cell lymphatic metastasis exosome dependently, and aided by the soluble fraction, the exosome-dependent CD97 plays a pivotal role in premetastatic niche formation.

High cut-off dialysis in chronic haemodialysis patients

BACKGROUND

Haemodialysis patients suffer from chronic systemic inflammation and high incidence of cardiovascular disease. One cause for this may be the failure of diseased kidneys to eliminate immune mediators. Current haemodialysis treatment achieves insufficient elimination of proteins in the molecular weight range 15-45 kD. Thus, high cut-off dialysis might improve the inflammatory state.

DESIGN

In this randomized crossover trial, 43 haemodialysis patients were treated for 3 weeks with high cut-off or high-flux dialysis. Inflammatory plasma mediators, monocyte subpopulation distribution and leucocyte gene expression were quantified.

RESULTS

High cut-off dialysis supplemented by a low-flux filter did not influence the primary end-point, expression density of CD162 on monocytes. Nevertheless, treatment reduced multiple immune mediators in plasma. Such reduction proved - at least for some markers - to be a sustained effect over the interdialytic interval. Thus, for example, soluble TNF-receptor 1 concentration predialysis was reduced from median 13·3 (IQR 8·9-17·2) to 9·7 (IQR 7·5-13·2) ng/mL with high cut-off while remaining constant with high-flux treatment. The expression profile of multiple proinflammatory genes in leucocytes was significantly dampened. Treatment was well tolerated although albumin losses in high cut-off dialysis would be prohibitive against long-term use.

CONCLUSIONS

The study shows for the first time that a dampening effect of high cut-off dialysis on systemic inflammation is achievable. Earlier studies had failed due to short study duration or insufficient dialysis efficacy. Removal of soluble mediators from the circulation influences cellular activation levels in leucocytes. Continued development of less albumin leaky membranes with similar cytokine elimination is justified.

Phosphorylation of pyruvate kinase M2 and lactate dehydrogenase A by fibroblast growth factor receptor 1 in benign and malignant thyroid tissue

BACKGROUND

Lactate dehydrogenase A (LDHA) and Pyruvate Kinase M2 (PKM2) are important enzymes of glycolysis. Both of them can be phosphorylated and therefore regulated by Fibroblast growth factor receptor 1 (FGFR1). While phosphorylation of LDHA at tyrosine10 leads to tetramerization and activation, phosphorylation of PKM2 at tyrosine105 promotes dimerization and inactivation. Dimeric PKM2 is found in the nucleus and regulates gene transcription. Up-regulation and phosphorylation of LDHA and PKM2 contribute to faster proliferation under hypoxic conditions and promote the Warburg effect.

METHODS

Using western blot and SYBR Green Real time PCR we investigated 77 thyroid tissues including 19 goiter tissues, 11 follicular adenomas, 16 follicular carcinomas, 15 papillary thyroid carcinomas, and 16 undifferentiated thyroid carcinomas for total expression of PKM2, LDHA and FGFR1. Additionally, phosphorylation status of PKM2 and LDHA was analysed. Inhibition of FGFR was performed on FTC133 cells with SU-5402 and Dovitinib.

RESULTS

All examined thyroid cancer subtypes overexpressed PKM2 as compared to goiter. LDHA was overexpressed in follicular and papillary thyroid cancer as compared to goiter. Elevated phosphorylation of LDHA and PKM2 was detectable in all analysed cancer subtypes. The highest relative phosphorylation levels of PKM2 and LDHA compared to overall expression were found in undifferentiated thyroid cancer. Inhibition of FGFR led to significantly decreased phosphorylation levels of PKM2 and LDHA.

CONCLUSIONS

Our data shows that overexpression and increased phosphorylation of PKM2 and LHDA is a common finding in thyroid malignancies. Phospho-PKM2 and Phospho-LDHA could be valuable tumour markers for thyroglobulin negative thyroid cancer.

Uremic conditions drive human monocytes to pro-atherogenic differentiation via an angiotensin-dependent mechanism

Aims

Elevated expression levels of monocytic-ACE have been found in haemodialysis patients. They are not only epidemiologically linked with increased mortality and cardiovascular disease, but may also directly participate in the initial steps of atherosclerosis. To further address this question we tested the role of monocytic-ACE in promotion of atherosclerotic events in vitro under conditions mimicking those of chronic renal failure.

Methods and Results

Treatment of human primary monocytes or THP-1 cells with uremic serum as well as PMA-induced differentiation led to significantly up-regulated expression of ACE, further increased by additional treatment with LPS. Functionally, these monocytes revealed significantly increased adhesion and transmigration through endothelial monolayers. Overexpression of ACE in transfected monocytes or THP-1 cells led to development of more differentiated, macrophage-like phenotype with up-regulated expression of Arg1, MCSF, MCP-1 and CCR2. Expression of pro-inflammatory cytokines TNFa and IL-6 were also noticeably up-regulated. ACE overexpression resulted in significantly increased adhesion and transmigration properties. Transcriptional screening of ACE-overexpressing monocytes revealed noticeably increased expression of Angiotensin II receptors and adhesion- as well as atherosclerosis-related ICAM-1 and VCAM1. Inhibition of monocyte ACE or AngII-receptor signalling led to decreased adhesion potential of ACE-overexpressing cells.

Conclusions

Taken together, these data demonstrate that uremia induced expression of monocytic-ACE mediates the development of highly pro-atherogenic cells via an AngII-dependent mechanism.

The invasion and metastasis promotion role of CD97 small isoform in gastric carcinoma

CD97 is over-expressed in the majority of gastric adenocarcinomas and is associated with its dedifferentiation and aggressiveness. Our previous results demonstrated that out of three CD97 isoforms tested, only the small one was able to promote increased invasiveness in vitro. Based on these data we further aimed to investigate the role of CD97 small isoform in gastric cancer progression in vivo by employing the cells with a stable CD97 small isoform knock-down and an orthotopic gastric cancer mouse model. We could demonstrate that the knock down of CD97/EGF1,2,5, led to a significant decrease in the number of cells penetrating the gelatin coated membrane as compared with control cells. In the gastric cancer mouse model, both the hypodermic and the orthotopic yielded tumor masses of the CD97/EGF1,2,5kd group and were significantly smaller than the control. Metastatic tumor cell number in early metastatic regional lymph nodes on post-operative day 42 was distinctly decreased in the CD97/EGF1,2,5kd group as compared with the SGC-NS group, and was accompanied with the downregulation of CD44, VEGFR, CD31 and CD97. We concluded in this study that CD97 small isoform not only supported gastric cancer local growth, but also promoted metastatic spread in orthotopically implanted mouse model suggesting involvement of the CD97 small isoform in the preparation of (pre)metastatic niche.

AUF1 and HuR: possible implications of mRNA stability in thyroid function and disorders

Abstract

RNA-binding proteins may regulate every aspect of RNA metabolism, including pre-mRNA splicing, mRNA trafficking, stability and translation of many genes. The dynamic association of these proteins with RNA defines the lifetime, cellular localization, processing and the rate at which a specific mRNA is translated. One of the pathways involved in regulating of mRNA stability is mediated by adenylate uridylate-rich element (ARE) binding proteins. These proteins are involved in processes of apoptosis, tumorigenesis and development. Out of many ARE-binding proteins, two of them AUF1 and HuR were studied most extensively and reported to regulate the mRNA stability in vivo. Our previously published data demonstrate that both proteins are involved in thyroid carcinogenesis. Several other reports postulate that mRNA binding proteins may participate in thyroid hormone actions. However, until now, exacts mechanisms and the possible role of post-transcriptional regulation and especially the role of AUF1 and HuR in those processes remain not fully understood. In this study we shortly review the possible function of both proteins in relation to development and various physiological and pathophysiological processes, including thyroid function and disorders.

Down-regulation of TM4SF is associated with the metastatic potential of gastric carcinoma TM4SF members in gastric carcinoma

Background

The aim of this study was to clarify the clinical significance of TM4SF members CD9, CD63 and CD82 in human gastric carcinoma.

Methods

By employing RT-PCR and immunohistochemistry, we studied the expression of CD9, CD63 and CD82 in 49 paired tissue specimens of normal gastric mucosa and carcinoma. All tissues were obtained from patients who underwent curative surgery.

Results

All normal gastric epithelium and gastric ulcer tissues strongly expressed transcripts and proteins of CD9, CD63 and CD82 as compared with corresponding controls. We found a significant correlation between CD63 mRNA level and different pM statuses (P = 0.036). Carcinomas in M0 stage revealed a stronger expression of CD63 than carcinomas in M1 stage. Expression of CD9 protein was found significantly stronger in pN0, pM0 than in advanced pN stages (P = 0.03), pM1 (P = 0.013), respectively. We found the relationship between CD63 expression, gender (p = 0.09) and nodal status (p = 0.028), respectively. Additionally, advanced and metastasized tumor tissues revealed significantly down-regulated CD82 protein expression (p = 0.033 and p = 0, respectively), which correlated with the tumor pTNM stage (p = 0.001).

Conclusion

The reduction of CD9, CD63 and CD82 expression are indicators for the metastatic potential of gastric carcinoma cells. Unlike their expression in other tumor types, the constitutive expression of CD63 may indicate that this factor does play a direct role in human gastric carcinogenesis.

Proteomic approach reveals novel targets for retinoic acid-mediated therapy of thyroid carcinoma

Our previous studies demonstrated that retinoic acid (RA)-induced reduction of both, the key glycolytic enzyme ENO1 and proliferation-promoting c-Myc, resulted in decreased vitality and invasiveness of the follicular thyroid carcinoma cell lines FTC-133 and FTC-238. By employing two-dimensional electrophoresis and mass spectrometry, we identified proteins affected by RA treatment. In addition to previously reported decrease in ENO1 expression, we found that RA led to significantly reduced levels of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), pyruvate kinase isoenzymes M1/M2 (PKM1/M2), peptidyl-prolyl cis-trans isomerase A (PPIA), transketolase (TKT), annexin A2 (ANXA2), glutathione S-transferase P (GSTP1) and peroxiredoxin 2 (PRDX2) as compared to untreated control. The same proteins investigated on thyroid tissues were found to be significantly up-regulated in follicular, papillary and undifferentiated thyroid carcinomas when compared with goiter and adenoma tissues. These findings identify new target proteins for RA-mediated anti-tumor and re-differentiation therapies and provide novel insights into treatments for thyroid carcinoma.

Role of CD97 isoforms in gastric carcinoma

The aim of this study was to elucidate the role of CD97 isoforms in gastric carcinoma. Out of four gastric cancer cell lines investigated, BGC-823 cells demonstrating low CD97 protein expression were stably transfected with pcDNA3.1 vector containing CD97/EGF1,2,5 or CD97/EGF1,2,3,4,5 inserts. Behavior of transfected cells was systematically investigated by employing proliferation, motility and invasive assays. As a result, we found that over-expression of CD97/EGF1,2,5 isoform correlated with increased motile and invasive ability of the clones. Furthermore, CD97/EGF1,2,5 isoform over-expression (3.8 times higher) was followed by significant decrease of CD97/EGF1,2,3,4,5 isoform (10.3 times lower). In contrast, CD97/EGF1,2,3,4,5 clones revealed significantly reduced invasive properties as compared with corresponding controls. The changes in acetylation status were one of the possible mechanisms affecting behavior of transfected cells. We concluded from the study that CD97 is closely related with advanced stages and higher invasiveness of gastric carcinoma. The study further lightened the tumor promoting role of CD97 small isoform in cancer progression and indicated the possible suppressive properties of the full length isoform of CD97.

The role of AUF1 in thyroid carcinoma progression

AUF1/heterogeneous nuclear ribonucleoprotein D is an adenylate-uridylate-rich elements (AREs) -binding protein, which regulates the mRNA stability of many genes related to growth regulation, such as proto-oncogenes, growth factors, cytokines, and cell cycle-regulatory genes. Several studies demonstrated AUF1 involvement in the processes of apoptosis, tumorigenesis, and development by its interactions with ARE-bearing mRNAs. We report here that AUF1 may be involved in thyroid carcinoma progression. Investigations on thyroid tissues revealed that cytoplasmic expression of AUF1 in malignant tissues was increased when compared with benign thyroid tissues. In thyroid carcinoma cell lines, AUF1 was mostly detectable in the nucleus; however, in dividing cells, its increased production was also observed in the cytoplasm. We found AUF1 in complexes with ARE-bearing mRNAs, previously described to be crucial for proliferation and cell cycle of thyroid carcinoma. Total or exon-selective knockdown of AUF1 led to growth inhibition accompanied by induction of cell cycle inhibitors and decreased levels of cell cycle promoters. Our data demonstrate the existence of a complex network between AUF1 and mRNAs encoding proteins related to cell proliferation. AUF1 may control the balance between stabilizing and destabilizing effects, both of which are exerted on cell cycle machinery in thyroid carcinoma. Although we cannot exclude participation of other factors, thyroid carcinoma may recruit cytoplasmic AUF1 to disturb the stability of mRNAs encoding cyclin-dependent kinase inhibitors, leading to uncontrolled growth and progression of tumor cells. Thus, AUF1 may be considered as a new, additional marker for thyroid carcinoma.

Retinoic acid-mediated down-regulation of ENO1/MBP-1 gene products caused decreased invasiveness of the follicular thyroid carcinoma cell lines

Retinoic acid (RA) acts as an anti-proliferative and redifferentiation agent in the therapy of thyroid carcinoma. Our previous studies demonstrated that pretreatment of follicular thyroid carcinoma cell lines FTC-133 and FTC-238 resulted in decreased in vitro proliferation rates and reduced tumor cell growth of xenotransplants. In addition to the previous results, we found that RA led to decreased vitality and invasiveness of FTC-133 and FTC-238 cells as they reacted with reduction of intracellular ATP levels and number of migrated cells respectively. However, the molecular mechanisms by which RA mediates these effects are not well understood. Two-dimensional (2D) screening of the proteins related to ATP metabolism and western blot analysis revealed alpha-enolase (ENO1) to be down-regulated in FTC-133 and FTC-238 cells after RA treatment. 2D gel detection and mass spectrometric analysis revealed that ENO1 existed as three separate protein spots of distinct pIs (ENO1-A1-A3). Comparative 2D difference gel electrophoresis analysis of fluorescently labeled protein samples of RA-treated and untreated FTC-133 demonstrated a selective down-regulation of ENO1-A1 which we identified as a phosphoprotein. RA caused the dephosphorylation of ENO1-A1. Both, RA-mediated and specific knock-down of ENO1/MBP-1 resulted in the reduction of MYC oncoprotein, and simultaneously decreased proliferation rates of FTC-133 and FTC-238 cell lines. In summary, the RA-mediated down-regulation of the ENO1 gene products and MYC oncoprotein provides a novel molecular mechanism facilitating the anti-proliferative effect of RA in human thyroid carcinoma cells and suggests new pathways for supportive RA therapies.

Relaxin enhances the oncogenic potential of human thyroid carcinoma cells

The role of members of the insulin-like superfamily in human thyroid carcinoma is primarily unknown. Here we demonstrate the presence of RLN2 relaxin and relaxin receptor LGR7 in human papillary, follicular, and undifferentiated anaplastic thyroid carcinoma suggesting a specific involvement of relaxin-LGR7 signaling in thyroid carcinoma. Stable transfectants of the LGR7-positive human follicular thyroid carcinoma cell lines FTC-133 and FTC-238 that secrete bioactive proRLN2 revealed this hormone to act as a multifunctional endocrine factor in thyroid carcinoma cells. Although RLN2 did not act as a mitogen, it acted as an autocrine/paracrine factor and significantly increased anchorage-independent growth and thyroid carcinoma cell motility and invasiveness through elastin matrices. Suppression of LGR7 expression by LGR7-siRNA abolished the RLN2-mediated accelerated tumor cell motility. The increased elastinolytic activity correlated with enhanced production and secretion of the lysosomal proteinases cathepsin-D (cath-D) and cath-L forms hereby identified as new RLN2 target molecules in human neoplastic thyrocytes. We found the intracellular distribution of procath-L specifically altered in RLN2 transfectants, providing first evidence for selective actions of relaxin on the powerful elastinolytic cath-L production, storage, and secretion in thyroid carcinoma cells. Thus, relaxin enhances the oncogenic potential and acts as novel endocrine modulator of invasiveness in human thyroid carcinoma cells.

CD82, and CD63 in thyroid cancer

CD82 (KAI1) and CD63 (ME491) are highly glycosylated proteins which belong to the transmembrane 4 superfamily (TM4SF). CD82 has been implicated as a possible prostate cancer metastasis suppressor gene, whereas CD63 is involved in the progression of human melanoma cancer. Down-regulation of both CD82 and CD63 expression has been associated with the metastatic potential of several solid tumors. Currently, information is lacking on the role of CD82 and CD63 during thyroid carcinogenesis. The aim of this study was to determine whether the expression of CD82 and CD63 is a useful prognostic indicator in patients with thyroid carcinoma. The expression of CD82 and CD63 was analysed by reverse transcriptase-PCR (RT-PCR) and immunohistochemistry in benign goiter (n=12) and 75 primary thyroid carcinoma tissue specimens (PTC: 33, FTC: 24, UTC: 18) out of which 36 were non-metastasized primary tumors and 39 were metastasized tumors (regional lymph node and/or distant metastases). All of the benign goiter tissues showed CD82 expression. By contrast, a significant decrease in CD82 mRNA and protein levels was detected in carcinoma tissues as compared to benign goiter tissues (p<0.001). A similar down-regulation was observed in metastasized tumor tissues when compared with non-metastasized tumors (all p<0.05). CD82 expression was correlated with pTNM status of differentiated and undifferentiated thyroid tumor and the pathologic stage of differentiated thyroid tumor. In contrast to CD82, CD63 mRNA and protein expression was unchanged in all thyroid carcinomas. Benign goiter tissues showed weak expression of CD63. There were no significant correlation between CD63 mRNA/protein expression and any clinical/pathological parameters. Our results support the hypothesis that down-regulation of CD82 expression may reflect an increased in vivo metastatic potential of thyroid cancer cells. CD82 may serve as a prognostic marker of metastasis in thyroid cancer. Constitutive expression of CD63 may indicate that this factor does not play a direct role in thyroid carcinogenesis.