Mouse CCL9 Chemokine Acts as Tumor Suppressor in a Murine Model of Colon Cancer.

Colorectal cancer is the third most frequently diagnosed cancer in the world. Despite extensive studies and apparent progress in modern strategies for disease control, the treatment options are still not sufficient and effective, mostly due to frequently encountered resistance to immunotherapy of colon cancer patients in common clinical practice. In our study, we aimed to uncover the CCL9 chemokine action employing the murine model of colon cancer to seek new, potential molecular targets that could be promising in the development of colon cancer therapy. Mouse CT26.CL25 colon cancer cell line was used for introducing lentivirus-mediated CCL9 overexpression. The blank control cell line contained an empty vector, while the cell line marked as CCL9+ carried the CCL9-overexpressing vector. Next, cancer cells with empty vector (control) or CCL9-overexpressing cells were injected subcutaneously, and the growing tumors were measured within 2 weeks. Surprisingly, CCL9 contributed to a decline in tumor growth in vivo but had no effect on CT26.CL25 cell proliferation or migration in vitro. Microarray analysis of the collected tumor tissues revealed upregulation of the immune system-related genes in the CCL9 group. Obtained results suggest that CCL9 reveals its anti-proliferative functions by interplay with host immune cells and mediators that were absent in the isolated, in vitro system. Under specific study conditions, we determined unknown features of the murine CCL9 that have so far bee reported to be predominantly pro-oncogenic.

The Journey of Cancer Cells to the Brain: Challenges and Opportunities.

Cancer metastases into the brain constitute one of the most severe, but not uncommon, manifestations of cancer progression. Several factors control how cancer cells interact with the brain to establish metastasis. These factors include mediators of signaling pathways participating in migration, infiltration of the blood-brain barrier, interaction with host cells (e.g., neurons, astrocytes), and the immune system. Development of novel therapies offers a glimpse of hope for increasing the diminutive life expectancy currently forecasted for patients suffering from brain metastasis. However, applying these treatment strategies has not been sufficiently effective. Therefore, there is a need for a better understanding of the metastasis process to uncover novel therapeutic targets. In this review, we follow the journey of various cancer cells from their primary location through the diverse processes that they undergo to colonize the brain. These processes include EMT, intravasation, extravasation, and infiltration of the blood-brain barrier, ending up with colonization and angiogenesis. In each phase, we focus on the pathways engaging molecules that potentially could be drug target candidates.

Activin receptor-like kinase 1 is associated with immune cell infiltration and regulates CLEC14A transcription in cancer.

Cancer cells sustain their metabolic needs through nutrients and oxygen supplied by the bloodstream. The requirement for tumor angiogenesis has been therapeutically exploited in the clinical setting mainly by means of inhibition of the vascular endothelial growth factor family of ligands and receptors. Despite promising results in preclinical models, the benefits for patients proved to be limited. Inadequate efficacy similarly halted the development of agents impinging on the activity of the activin receptor-like kinase (ALK)1, a member of the transforming growth factor-ß superfamily. Notwithstanding its characterization as an endothelial cell marker, the full spectrum of biological processes associated with ALK1 is essentially unexplored. Here, we present data revealing the genetic network associated with ACVRL1 (the gene encoding for ALK1) expression in human cancer tissues. Computational analysis unveiled a hitherto unknown role for ACVRL1 in relation to genes modulating the functionality of the immune cell compartment. Moreover, we generated a signature of 8 genes co-expressed with ACVRL1 across different tumor types and characterized the c-type lectin domain containing protein (CLEC)14A as a potential downstream target of ACVRL1. Considering the lack of reagents for ALK1 detection that has hampered the field to date, our work provides the opportunity to validate the 8-gene signature and CLEC14A as biomarkers for ALK1 activity. Ultimately, this may help revisit the clinical development of already existing ALK1-blocking compounds as precision medicines for cancer.

Effect of Chemokine (C-C Motif) Ligand 7 (CCL7) and Its Receptor (CCR2) Expression on Colorectal Cancer Behaviors.

Colorectal cancer is the source of one of the most common cancer-related deaths worldwide, where the main cause of patient mortality remains metastasis. The aim of this study was to determine the role of CCL7 (chemokine (C-C motif) ligand 7) in tumor progression and finding whether it could predict survival of colorectal cancer patients. Initially, our study focused on the crosstalk between mesenchymal stem cells (MSCs) and CT26 colon carcinoma cells and resulted in identifying CCL7 as a chemokine upregulated in CT26 colon cancer cells cocultured with MSCs, compared with CT26 in monoculture in vitro. Moreover, we showed that MSCs enhance CT26 tumor cell proliferation and migration. We analyzed the effect of CCL7 overexpression on tumor progression in a murine CT26 model, where cells overexpressing CCL7 accelerated the early phase of tumor growth and caused higher lung metastasis rates compared with control mice. Microarray analysis revealed that tumors overexpressing CCL7 had lower expression of immunoglobulins produced by B lymphocytes. Additionally, using Jh mutant mice, we confirmed that in the CT26 model, CCL7 has an immunoglobulin-, and thereby, B-cell-dependent effect on metastasis formation. Finally, higher expression of CCL7 receptor CCR2 (C-C chemokine receptor type 2) was associated with shorter overall survival of colorectal cancer patients. Altogether, we showed that CCL7 is essentially involved in the progression of colorectal cancer in a CT26 mouse model and that the expression of its receptor CCR2 could be related to a different outcome pattern of patients with colorectal carcinoma.

Human cytomegalovirus-platelet interaction triggers toll-like receptor 2-dependent proinflammatory and proangiogenic responses.

OBJECTIVE: Human cytomegalovirus (HCMV) is a widespread pathogen that correlates with various clinical complications, including atherosclerosis. HCMV is released into the circulation during primary infection and periodic viral reactivation, allowing virus-platelet interactions. Platelets are important in the onset and development of atherosclerosis, but the consequences of platelet-HCMV interactions are unclear. APPROACH AND RESULTS: We studied the effects of HCMV-platelet interactions in blood from healthy donors using the purified clinical HCMV isolate VR1814. We demonstrated that HCMV bound to a Toll-like receptor (TLR) 2-positive platelet subpopulation, which resulted in signal transduction, degranulation, and release of proinflammatory CD40L and interleukin-1ß and proangiogenic vascular endothelial-derived growth factor. In mice, murine CMV activated wild-type but not TLR2-deficient platelets. However, supernatant from murine CMV-stimulated wild-type platelets also activated TLR2-deficient platelets, indicating that activated platelets generated soluble mediators that triggered further platelet activation, independent of TLR2 expression. Inhibitor studies, using ADP receptor antagonists and apyrase, revealed that ADP release is important to trigger secondary platelet activation in response to HCMV. HCMV-activated platelets rapidly bound to and activated neutrophils, supporting their adhesion and transmigration through endothelial monolayers. In an in vivo model, murine CMV induced systemic upregulation of platelet-leukocyte aggregates and plasma vascular endothelial-derived growth factor in mice and showed a tendency to enhance neutrophil extravasation in a TLR2-dependent fashion. CONCLUSIONS: HCMV is a well-adapted pathogen that does not induce immediate thrombotic events. However, HCMV-platelet interactions lead to proinflammatory and proangiogenic responses, which exacerbate tissue damage and contribute to atherogenesis. Therefore, platelets might contribute to the effects of HCMV in accelerating atherosclerosis.

Monocyte chemoattractant protein 1-mediated migration of mesenchymal stem cells is a source of intimal hyperplasia.

OBJECTIVE: Intimal hyperplasia is considered to be a healing response and is a major cause of vessel narrowing after injury, where migration of vascular progenitor cells contributes to pathological events, including transplant arteriosclerosis. APPROACH AND RESULTS: In this study, we used a rat aortic-allograft model to identify the predominant cell types associated with transplant arteriosclerosis and to identify factors important in their recruitment into the graft. Transplantation of labeled adventitial tissues allowed us to identify the adventitia as a major source of cells migrating to the intima. RNA microarrays revealed a potential role for monocyte chemoattractant protein 1 (MCP-1), stromal cell-derived factor 1, regulated on activation, normal T cell expressed and secreted, and interferon-inducible protein 10 in the induced vasculopathy. MCP-1 induced migration of adventitial fibroblast cells. CCR2, the receptor for MCP-1, was coexpressed with CD90, CD44, NG2, or sca-1 on mesenchymal stem cells. In vivo experiments using MCP-1-deficient and CCR2-deficient mice confirmed an important role of MCP-1 in the formation of intimal hyperplasia in a mouse model of vascular injury. CONCLUSIONS: The adventitia is a potentially important cellular source that contributes to intimal hyperplasia, and MCP-1 is a potent chemokine for the recruitment of adventitial vascular progenitor cells to intimal lesions.

Exercise reduces intramuscular stress and counteracts muscle weakness in mice with breast cancer.

BACKGROUND: Patients with breast cancer exhibit muscle weakness, which is associated with increased mortality risk and reduced quality of life. Muscle weakness is experienced even in the absence of loss of muscle mass in breast cancer patients, indicating intrinsic muscle dysfunction. Physical activity is correlated with reduced cancer mortality and disease recurrence. However, the molecular processes underlying breast cancer-induced muscle weakness and the beneficial effect of exercise are largely unknown. METHODS: Eight-week-old breast cancer (MMTV-PyMT, PyMT) and control (WT) mice had access to active or inactive in-cage voluntary running wheels for 4 weeks. Mice were also subjected to a treadmill test. Muscle force was measured ex vivo. Tumour markers were determined with immunohistochemistry. Mitochondrial biogenesis and function were assessed with transcriptional analyses of PGC-1α, the electron transport chain (ETC) and antioxidants superoxide dismutase (Sod) and catalase (Cat), combined with activity measurements of SOD, citrate synthase (CS) and ß-hydroxyacyl-CoA-dehydrogenase (ßHAD). Serum and intramuscular stress levels were evaluated by enzymatic assays, immunoblotting, and transcriptional analyses of, for example, tumour necrosis factor-α (TNF-α) and p38 mitogen-activated protein kinase (MAPK) signalling. RESULTS: PyMT mice endured shorter time and distance during the treadmill test (~30%, P < 0.05) and ex vivo force measurements revealed ~25% weaker slow-twitch soleus muscle (P < 0.001). This was independent of cancer-induced alteration of muscle size or fibre type. Inflammatory stressors in serum and muscle, including TNF-α and p38 MAPK, were higher in PyMT than in WT mice (P < 0.05). Cancer-induced decreases in ETC (P < 0.05, P < 0.01) and antioxidant gene expression were observed (P < 0.05). The exercise intervention counteracted the cancer-induced muscle weakness and was accompanied by a less aggressive, differentiated tumour phenotype, determined by increased CK8 and reduced CK14 expression (P < 0.05). In PyMT mice, the exercise intervention led to higher CS activity (P = 0.23), enhanced ß-HAD and SOD activities (P < 0.05), and reduced levels of intramuscular stressors together with a normalization of the expression signature of TNFα-targets and ETC genes (P < 0.05, P < 0.01). At the same time, the exercise-induced PGC-1α expression, and CS and ß-HAD activity was blunted in muscle from the PyMT mice as compared with WT mice, indicative that breast cancer interfere with transcriptional programming of mitochondria and that the molecular adaptation to exercise differs between healthy mice and those afflicted by disease. CONCLUSIONS: Four-week voluntary wheel running counteracted muscle weakness in PyMT mice which was accompanied by reduced intrinsic stress and improved mitochondrial and antioxidant profiles and activities that aligned with muscles of healthy mice.

A high red blood cell distribution width predicts failure of arteriovenous fistula.

In hemodialysis patients, a native arteriovenous fistula (AVF) is the preferred form of permanent vascular access. Despite recent improvements, vascular access dysfunction remains an important cause of morbidity in these patients. In this prospective observational cohort study, we evaluated potential risk factors for native AVF dysfunction. We included 68 patients with chronic renal disease stage 5 eligible for AVF construction at the Department of General and Vascular Surgery, Central Clinical Hospital Ministry of Internal Affairs, Warsaw, Poland. Patient characteristics and biochemical parameters associated with increased risk for AVF failure were identified using Cox proportional hazards models. Vessel biopsies were analyzed for inflammatory cells and potential associations with biochemical parameters. In multivariable analysis, independent predictors of AVF dysfunction were the number of white blood cells (hazard ratio [HR] 1.67; 95% confidence interval [CI] 1.24 to 2.25; p<0.001), monocyte number (HR 0.02; 95% CI 0.00 to 0.21; p = 0.001), and red blood cell distribution width (RDW) (HR 1.44; 95% CI 1.17 to 1.78; p<0.001). RDW was the only significant factor in receiver operating characteristic curve analysis (area under the curve 0.644; CI 0.51 to 0.76; p = 0.046). RDW>16.2% was associated with a significantly reduced AVF patency frequency 24 months after surgery. Immunohistochemical analysis revealed CD45-positive cells in the artery/vein of 39% of patients and CD68-positive cells in 37%. Patients with CD68-positive cells in the vessels had significantly higher white blood cell count. We conclude that RDW, a readily available laboratory value, is a novel prognostic marker for AVF failure. Further studies are warranted to establish the mechanistic link between high RDW and AVF failure.