Selectively frequent expression of CXCR5 enhances resistance to apoptosis in CD8(+)CD34(+) T cells from patients with T-cell-lineage acute lymphocytic leukemia

The Diagnostic Significance of CXCL13 in M2 Tumor Immune Microenvironment of Human Astrocytoma

Background: CXCL13 may act as a mediator of tumor-associated macrophage immunity during malignant progression. Objective: The present study clarifies the clinicopathological significances of CXCL13 and its corresponding trend with M2 macrophage in human astrocytoma. Methods: The predictive potential of CXCL13 was performed using 695 glioma samples derived from TCGA lower-grade glioma and glioblastoma (GBMLGG) dataset. CXCL13 and M2 biomarker CD163 were observed by immunohistochemistry in 112 astrocytoma tissues. Results: An in-depth analysis showed that CXCL13 expression was related to the poor prognosis of glioma patients (p = 0.0002) derive from TCGA analysis. High level of CXCL13 was detected in 43 (38.39%) astrocytoma and CXCL13/CD163 coexpression was expressed in 33 (29.46%) cases. The immunoreactivities of CXCL13 and CXCL13/CD163 were found in the malignant lesions, which were both significantly associated with grade, patient survival, and IDH1 mutation. Single CXCL13 and CXCL13/CD163 coexpression predicted poor overall survival in astrocytoma (p = 0.0039 and p = 0.0002, respectively). Multivariate Cox regression analyses manifested CXCL13/CD163 phenotype was a significant independent prognostic indicator of patient outcome in astrocytoma (CXCL13, p = 0.0642; CXCL13/CD163, p = 0.0368). Conclusion: CXCL13 overexpression is strongly linked to CD163+ M2 infiltration in malignant astrocytoma. CXCL13/CD163 coexpression would imply M2c-related aggressive characteristics existing in astrocytoma progression could also provide predictive trends of patient outcomes.

CXCR5+ CD8+ T cells potently infiltrate pancreatic tumors and present high functionality

Despite continued improvement in conventional therapy, pancreatic cancer continues to be one of the deadliest tumors worldwide with abysmal 5-year survival rate. New immunotherapeutic strategies that aim at improving antitumor cytotoxic CD8⁺ T cell responses are being developed in solid tumors. To assist the development of immunotherapies, we investigated the CD8⁺ T cells in pancreatic cancer patients. Compared to healthy individuals, pancreatic cancer patients presented a significant enrichment in the frequency of CD8⁺CXCR5⁺ T cells. In the tumor microenvironment, the frequencies of CD8⁺CXCR5⁺ T cells were further increased. In most cases, over half of tumor-infiltrating CD8⁺ T cells were CD8⁺CXCR5⁺ T cells. Compared to the circulating population, the tumor-infiltrating CD8⁺CXCR5⁺ T cells expressed higher levels of PD-1 and TIM-3. Functional analyses demonstrated that upon CD3/CD28 activation, the percentages of TNF-expressing and IFN-γ-expressing cells in CD8⁺CXCR5⁺ T cells were significantly higher than that in CD8⁺CXCR5^- T cells. CD8⁺CXCR5⁺ T cells also presented enhanced cytotoxicity than CD8⁺CXCR5^- T cells. Upon PD-1 and TIM-3 blockade, the functions of CD8⁺CXCR5⁺ T cells were further improved. The disease-free survival of pancreatic cancer patients following tumor resection was positively correlated with the frequencies of circulating and tumor-infiltrating CD8⁺CXCR5⁺ T cells. Together, our study identified that CD8⁺CXCR5⁺ T cells were a potent subset of CD8⁺ T cells that were highly enriched in pancreatic cancer patients and could respond to anti-PD-1/anti-TIM-3 blockade by further upregulation in function.

Evidence of perturbed germinal center dynamics, but preserved antibody diversity, in end-stage renal disease

INTRODUCTION

End-stage renal disease (ESRD) is associated with increased infectious susceptibility and with reduced vaccine responses consistent with compromised humoral immunity. Whether the compromised humoral immunity is due to reduced antibody diversity (reduced somatic hypermutation [SHM]) or altered germinal center (GC) dynamics is not known. The GC-derived chemokine CXCL13 as well as peripheral T follicular helper cells (pTFH) reflect GC dynamics, but have, similar to SHM, never been characterized in relation to ESRD.

METHODS

Serum CXCL 13 was determined by ELISA. PTFH were flow-cytometrically defined as CD4⁺ CD45RA^- CCR7⁺ CXCR5⁺ lymphocytes. Apoptotic lymphocyte subsets were in addition annexin V⁺. SHM was determined, by next-generation sequencing and bioinformatics, as nucleotide mutations within the IgG V_H (comprising the important antigen-binding domains of IgG, CDR1, and CDR2).

RESULTS

Elevated CXCL13 levels characterized ESRD (n = 19; [median] 90 pg/ml, P < 0.01) (controls, n = 18; 62 pg/ml). ESRD pTFH frequencies (n = 19; 11.6% [of CD4⁺ memory T cells], P < 0.02*, *Bonferroni corrected) (controls, n = 22; 14.9%) and concentrations (n = 19; 0.03 × 10⁹/L, P < 0.02*) (controls, n = 22; 0.07 × 10⁹/L) were reduced. ESRD pTFH were more apoptotic (n = 9; 25.7%, P = 0.04*) (controls, n = 10; 15.9%). SHM did not discriminate between ESRD (n = 10; 7.4%, P = 0.21) and controls (n = 10; 8.4%).

CONCLUSIONS

Elevated CXCL13 levels, reduced pTFH levels, and increased pTFH apoptosis suggest that perturbed GC dynamics, and not reduced antibody diversity, underlie the diminished vaccine responses and the compromised humoral immunity in ESRD. However, largely preserved SHM provides a rationale for pursuing vaccination in relation to ESRD.

Down-regulation of miR-192-5p protects from oxidative stress-induced acute liver injury

miR-192-5p has gained increasing relevance in various diseases, however, its function in acute liver injury is currently unknown. We analysed miR-192-5p serum levels and hepatic miR-192-5p expression in mice after hepatic ischaemia and reperfusion (I/R) as well as in toxic liver injury. On a functional level, miRNA levels were analysed in the different hepatic cell-compartments and in the context of tumour necrosis factor (TNF)-dependent liver cell death. We detected increased serum levels of miR-192-5p after hepatic I/R- and carbon tetrachloride (CCl4)-induced liver injury. miR-192-5p levels correlated with the degree of liver damage and the presence of hepatic cell death detected by TUNEL stainings (terminal deoxynucleotidyltransferase-mediated dUTP biotin nick-end labelling stainings). Moreover, expression of miR-192-5p was increased in a hypoxia/reoxygenation (H/R) model of in vitro hepatocyte injury, supporting that the passive release of miR-192-5p represents a surrogate for hepatocyte death in liver injury. In critically ill patients, miR-192-5p levels were elevated selectively in patients with liver injury and closely correlated with the presence of hepatic injury. In contrast with up-regulated miR-192-5p in the serum, we detected a down-regulation of miR-192-5p in both injured mouse and human livers. Deregulation of miR-192-5p in livers was dependent on stimulation with TNF. Functional experiments confirmed a protective effect of down-regulation of miR-192-5p in hepatocytes, suggesting a role of miR-192-5p in limiting liver injury. Finally, we identified Zeb2, an important regulator of cell death, as a potential target gene mediating the function of miR-192-5p. Our data suggest that miR-192-5p is involved in the regulation of liver cell death during acute liver injury and might represent a potent marker of hepatic injury.

Lack of chemokine signaling through CXCR5 causes increased mortality, ventricular dilatation and deranged matrix during cardiac pressure overload

RATIONALE

Inflammatory mechanisms have been suggested to play a role in the development of heart failure (HF), but a role for chemokines is largely unknown. Based on their role in inflammation and matrix remodeling in other tissues, we hypothesized that CXCL13 and CXCR5 could be involved in cardiac remodeling during HF.

OBJECTIVE

We sought to analyze the role of the chemokine CXCL13 and its receptor CXCR5 in cardiac pathophysiology leading to HF.

METHODS AND RESULTS

Mice harboring a systemic knockout of the CXCR5 (CXCR5(-/-)) displayed increased mortality during a follow-up of 80 days after aortic banding (AB). Following three weeks of AB, CXCR5(-/-) developed significant left ventricular (LV) dilatation compared to wild type (WT) mice. Microarray analysis revealed altered expression of several small leucine-rich proteoglycans (SLRPs) that bind to collagen and modulate fibril assembly. Protein levels of fibromodulin, decorin and lumican (all SLRPs) were significantly reduced in AB CXCR5(-/-) compared to AB WT mice. Electron microscopy revealed loosely packed extracellular matrix with individual collagen fibers and small networks of proteoglycans in AB CXCR5(-/-) mice. Addition of CXCL13 to cultured cardiac fibroblasts enhanced the expression of SLRPs. In patients with HF, we observed increased myocardial levels of CXCR5 and SLRPs, which was reversed following LV assist device treatment.

CONCLUSIONS

Lack of CXCR5 leads to LV dilatation and increased mortality during pressure overload, possibly via lack of an increase in SLRPs. This study demonstrates a critical role of the chemokine CXCL13 and CXCR5 in survival and maintaining of cardiac structure upon pressure overload, by regulating proteoglycans essential for correct collagen assembly.

Anti-tumor effects of CIK combined with oxaliplatin in human oxaliplatin-resistant gastric cancer cells in vivo and in vitro

BACKGROUND

Drug resistance remains a great challenge in the treatment of gastric cancer. The goal of this study was to explore the anti-tumor effects and mechanism of cytokine-induced killer (CIK) cell combined with oxaliplatin (L-OHP) in human oxaliplatin-resistant gastric cancer cells.

METHODS

After producing oxaliplatin-resistant gastric cancer cells, cell morphology, growth and doubling time were observed, followed by detection of cell cycle distribution and apoptosis, drug sensitivity (e.g., L-OHP) and expression of P-gp and livin. MTT assay, in vivo pharmacodynamics and pathomorphology experiments were used to detect killing activities of CIK combined with L-OHP.

RESULTS

Compared with parental gastric cancer cells, oxaliplatin-resistant gastric cancer cells in S phase were reduced and cell apoptosis rate was increased (P < 0.05), the inhibition rate of 10 chemotherapeutics on oxaliplatin-resistant gastric cancer cells was significantly lower and the expression of P-gp was significantly higher (P < 0.05). However, there was no significant difference in livin expression between parental gastric cancer cells and oxaliplatin-resistant gastric cancer cells (P > 0.05). The in vitro killing activity of CIK combined with L-OHP on parental cells and oxaliplatin-resistant cells were significantly enhanced compared with L-OHP or CIK alone. And it showed greater synergetic effects against oxaliplatin-resistant cells compared with parental cells (P < 0.05). In addition, survival rate, abdominal circumference and pathomorphology results revealed stronger in vivo anti-tumor effects when the two therapies were combined.

CONCLUSIONS

The mechanism of oxaliplatin-resistant cell secondary multidrug resistance was correlated with the variation of cell cycle distribution, extension of doubling time and upregulation of P-gp expression. The synergistic effect of CIK in combination with L-OHP on killing activity against oxaliplatin-resistant cells was shown in vivo and in vitro.

Chemokine CXCL13 is overexpressed in the tumour tissue and in the peripheral blood of breast cancer patients

The abilities of chemokines in orchestrating cellular migration are utilised by different (patho-)biological networks including malignancies. However, except for CXCR4/CXCL12, little is known about the relation between tumour-related chemokine expression and the development and progression of solid tumours like breast cancer. In this study, microarray analyses revealed the overexpression of chemokine CXCL13 in breast cancer specimens. This finding was confirmed by real-time polymerase chain reaction in a larger set of samples (n=34) and cell lines, and was validated on the protein level performing Western blot, ELISA, and immunohistochemistry. Levels of CXCR5, the receptor for CXCL13, were low in malignant and healthy breast tissues, and surface expression was not detected in vitro. However, we observed a strong (P=0.0004) correlation between the expressions of CXCL13 and CXCR5 in breast cancer tissues, indicating a biologically relevant role of CXCR5 in vivo. Finally, we detected significantly elevated serum concentrations of CXCL13 in patients with metastatic disease (n=54) as compared with controls (n=44) and disease-free patients (n=48). In conclusion, CXCL13 is overexpressed within breast cancer tissues, and increased serum levels of this cytokine can be found in breast cancer patients with metastatic disease pointing to a role of CXCL13 in the progression of breast cancer, suggesting that CXCL13 might serve as a useful therapeutic target and/or diagnostic marker in this malignancy.

Chemokine receptor CCR1 regulates inflammatory cell infiltration after renal ischemia-reperfusion injury

Neutrophils and macrophages rapidly infiltrate the kidney after renal ischemia-reperfusion injury, however specific molecular recruitment mechanisms have not been fully delineated for these cell types. Here we provide genetic and pharmacologic evidence supporting a positive role for the chemokine receptor CCR1 in macrophage and neutrophil infiltration in a 7 day mouse model of renal ischemia-reperfusion injury. By day 7, injured kidneys from mice lacking CCR1 contained 35% fewer neutrophils and 45% fewer macrophages than injured kidneys from wild-type control mice. Pretreatment of wild-type mice with the specific CCR1 antagonist BX471 also suppressed neutrophil and macrophage infiltration in the model. Injured kidneys from mice lacking CCR1 also had reduced content of the CCR1 ligands CCL3 (MIP-1alpha) and CCL5 (RANTES) compared with injured kidneys from wild-type controls, suggesting a leukocyte source for these inflammatory chemokines and existence of a CCR1-dependent positive feedback loop for leukocyte infiltration in the model. Local leukocyte proliferation and apoptosis were detected after injury, but were not dependent on CCR1. Also, the extent of necrotic and fibrotic damage and decline in renal function in injured kidneys was similar in wild-type and CCR1-deficient mice. Thus, CCR1 appears to regulate trafficking of macrophages and neutrophils to kidney in a mouse model of renal ischemia-reperfusion injury, however this activity does not appear to affect tissue injury.

The CXCR5 chemokine receptor is expressed by carcinoma cells and promotes growth of colon carcinoma in the liver

The chemokine receptor CXCR5 is expressed by B cells and certain T cells and controls their migration into and within lymph nodes. Its ligand BCA-1/CXCL13 is present in lymph nodes and spleen and also in the liver. Surprisingly, we detected CXCR5 in several mouse and human carcinoma cell lines. CXCR5 was particularly prominent in pancreatic carcinoma cell lines and was also detected by immunohistochemistry in 7 of 18 human pancreatic carcinoma tissues. Expression in CT26 colon carcinoma was low in vitro, up-regulated in vivo, and rapidly lost when cells were explanted in vitro. CXCL13 strongly promoted proliferation of CXCR5-transfected CT26 cells in vitro. In the liver, after intrasplenic injection, these CXCR5 transfectants initially grew faster than controls, but the growth rate of control tumors accelerated later to become similar to the transfectants, likely due to the up-regulation of CXCR5. Inhibition of CXCR5 function, by trapping CXCR5 in the endoplasmic reticulum using a CXCL13-KDEL "intrakine," had no effect on initial growth of liver foci but later caused a prolonged growth arrest. In contrast, s.c. and lung tumors of CXCR5- and intrakine-transfected cells grew at similar rates as controls. We conclude that expression of CXCR5 on tumor cells promotes the growth of tumor cells in the liver and, at least for CT26 cells, seems to be required for outgrowth to large liver tumors. Given the limited expression on normal cells, CXCR5 may constitute an attractive target for therapy, particularly for pancreatic carcinoma.