Nuclear factor-kappaB and tumor-associated macrophages

Tumor associated macrophage-targeted microRNA delivery with dual-responsive polypeptide nanovectors for anti-cancer therapy

Repolarizing Tumor-associated macrophages (TAMs) to anti-tumor M1 macrophages with microRNA (miR) is a plausible approach for cancer treatment. However, how to achieve TAM-targeted miR delivery remains a challenge. The present study generated redox/pH dual-responsive hybrid polypeptide nanovectors, which consisted of self-crosslinked redox-responsive nanoparticles based on galactose-functionalized n-butylamine-poly(l-lysine)-b-poly(l-cysteine) polypeptides (GLC) coated with DCA-grafted sheddable PEG-PLL (sPEG) copolymers. The ex vivo study showed that sPEG shielded cationic GLC core at physiological pH but quickly shed off to re-expose GLC due to it charge reversible property. Encapsulation with sPEG/GLC nanovectors effectively facilitated macrophage-targeted miR delivery at the acidic condition but diminished miR uptake at neutral pH. Administration of miR155-loaded sPEG/GLC (sPEG/GLC/155) nanocomplexes increased miR155 expression in TAMs about 100-400 folds both in vitro and in vivo. sPEG/GLC/155 also effectively repolarized immunosuppressive TAMs to anti-tumor M1 macrophages through elevating M1 macrophage markers (IL-12, iNOS, MHC II) and suppressing M2 macrophage markers (Msr2 and Arg1) in TAMs. Moreover, the treatment of sPEG/GLC/155 significantly increased activated T lymphocytes and NK cells in tumors, which consequently led to robust tumor regression. Hence, TAM-targeted delivery of miR with redox/pH dual-responsive sPEG/GLC nanovectors could be a promising approach to re-polarize TAMs to M1 macrophages in situ and induce tumor regression.

Role of tumour-associated macrophages in oral squamous cells carcinoma progression: an update on current knowledge

BACKGROUND

Oral squamous cell carcinoma (OSCC) accounts over 90% of malignant neoplasms of the oral cavity. This pathological entity is associated to a high mortality rate that has remained unchanged over the past decades. Tumour-associated macrophages (TAMs) are believed to have potential involvement in OSCC progression. However, the molecular networks involved in communication between stroma and cancer cells have not yet been fully elucidated.

MAIN BODY

The role of M2 polarized cells in oral carcinogenesis is supported by a correlation between TAMs accumulation into OSCC stroma and poor clinical outcome. Signalling pathways such as the NF-κB and cytokines released in the tumour microenvironment promote a bidirectional cross-talk between M2 and OSCC cells. These interactions consequently result in an increased proliferation of malignant cells and enhances aggressiveness, thus reducing patients' survival time.

CONCLUSIONS

Here, we present a comprehensive review of the role of interleukin (IL)-1, IL-4, IL-6, IL-8, IL-10 and the receptor tyrosine kinase Axl in macrophage polarization to an M2 phenotype and OSCC progression. Understanding the molecular basis of oral carcinogenesis and metastatic spread of OSCC would promote the development of targeted treatment contributing to a more favourable prognosis.

Immunomodulatory Effects of the Mycosporine-Like Amino Acids Shinorine and Porphyra-334

Mycosporine-like amino acids (MAAs) are secondary metabolites, produced by a large variety of microorganisms including algae, cyanobacteria, lichen and fungi. MAAs act as UV-absorbers and photo-protectants. MAAs are suggested to exert pharmaceutical relevant bioactivities in the human system. We particularly focused on their effect on defence and regulatory pathways that are active in inflamed environments. The MAAs shinorine and porphyra-334 were isolated and purified from the red algae Porphyra sp. using chromatographic methods. The effect of MAAs on central signaling cascades, such as transcription factor nuclear factor kappa b (NF-κB) activation, as well as tryptophan metabolism, was investigated in human myelomonocytic THP-1 and THP-1-Blue cells. Cells were exposed to the MAAs in the presence or absence of lipopolysaccharide (LPS). NF-κB activity and the activity of tryptophan degrading enzyme indoleamine 2,3-dioxygenase (IDO-1) were used as readout. Compounds were tested in the concentration range from 12.5 to 200 µg/mL. Both MAAs were able to induce NF-κB activity in unstimulated THP-1-Blue cells, whereby the increase was dose-dependent and more pronounced with shinorine treatment. While shinorine also slightly superinduced NF-κB in LPS-stimulated cells, porphyra-334 reduced NF-κB activity in this inflammatory background. Modulation of tryptophan metabolism was moderate, suppressive in stimulated cells with the lower treatment concentration of both MAAs and with the unstimulated cells upon porphyra-334 treatment. Inflammatory pathways are affected by MAAs, but despite the structural similarity, diverse effects were observed.

Endostatin inhibits the growth and migration of 4T1 mouse breast cancer cells by skewing macrophage polarity toward the M1 phenotype

The phenotypic diversity of tumor-associated macrophages (TAMs) increases with tumor development. One of the hallmarks of malignancy is the polarization of TAMs from a pro-immune (M1) phenotype to an immunosuppressive (M2) phenotype. However, the molecular basis of this process is still unclear. Endostatin is a powerful inhibitor of angiogenesis capable of suppressing tumor growth and metastasis. Here, we demonstrate that endostatin induces RAW264.7 cell polarization toward the M1 phenotype in vitro. Endostatin has no effect on TAM numbers in vivo, but results in an increased proportion of F4/80(+)Nos2(+) cells and a decreased proportion of F4/80(+)CD206(+) cells. Overexpression of endostatin in RAW264.7 cells resulted in a decrease in the phosphorylation of STAT3, an increase in expression of vascular endothelial growth factor A and placental growth factor, and an increase in the phosphorylation of STAT1, IκBα and p65 proteins compared with controls. These results indicate that endostatin regulates macrophage polarization, promoting the M1 phenotype by targeting NF-κB and STAT signaling.

Extracellular HSP110 skews macrophage polarization in colorectal cancer

HSP110 is induced by different stresses and, through its anti-apoptotic and chaperoning properties, helps the cells to survive these adverse situations. In colon cancers, HSP110 is abnormally abundant. We have recently showed that colorectal cancer (CRC) patients with microsatellite instability (MSI) had an improved response to chemotherapy because they harbor an HSP110 inactivating mutation (HSP110DE9). In this work, we have used patients' biopsies and human CRC cells grown in vitro and in vivo (xenografts) to demonstrate that (1) HSP110 is secreted by CRC cells and that the amount of this extracellular HSP110 is strongly decreased by the expression of the mutant HSP110DE9, (2) Supernatants from CRC cells overexpressing HSP110 or purified recombinant human HSP110 (LPS-free) affect macrophage differentiation/polarization by favoring a pro-tumor, anti-inflammatory profile, (3) Conversely, inhibition of HSP110 (expression of siRNA, HSP110DE9 or immunodepletion) induced the formation of macrophages with a cytotoxic, pro-inflammatory profile. (4) Finally, this effect of extracellular HSP110 on macrophages seems to implicate TLR4. These results together with the fact that colorectal tumor biopsies with HSP110 high were infiltrated with macrophages with a pro-tumoral profile while those with HSP110 low were infiltrated with macrophages with a cytotoxic profile, suggest that the effect of extracellular HSP110 function on macrophages may also contribute to the poor outcomes associated with HSP110 expression.

Effects of CIK on hypoxia inducible factor-1α and T-cell subsets on colon 26 cancer xenograft mice

Colorectal cancer is a common malignancy of the digestive tract with a high mortality rate. However, current treatment approaches such as radiotherapy and chemotherapy are ineffective. Thus, it is imperative to identify ways to treat recurrence and metastasis. The aim of the present study was to investigate the effects of cytokine-induced killer (CIK) cells on the hypoxia microenvironment and immune function in colon 26 cancer xenograft mice. A murine model of colon 26 carcinoma tumors were divided into CIK, normal saline (NS) and control groups. Hypoxia inducible factor-1α (HIF-1α) mRNA in tumor tissue and the small intestine of mice was detected by FQ-PCR. The percentage of the CD4⁺, CD8⁺ and CD4⁺/CD8⁺ ratio in the spleen of mice was detected by flow cytometry. The tumor volume in the CIK group was smaller than that in the NS group and the difference was not significant (P>0.05). HIF-1α gene expression was present in the tumor tissue and small intestine. HIF-1α gene expression in tumor tissue was significantly higher than that in the small intestine (P<0.05), and lower in tumor tissue of the CIK group compared to the NS group (P<0.05) of xenograft mice. However, no HIF-1α expression was observed in the small intestine of healthy control mice. CD4⁺ T-cell percentage and CD4⁺/CD8⁺ ratio in the spleen of xenograft mice was significantly lower than that of normal mice (P<0.05). Compared to the NS group, the CD4⁺ T-cell percentage was higher, whereas the CD8⁺ T-cell percentage was lower in the CIK group (P<0.05). In conclusion, HIF-1α gene expression was present in the tumor tissue and small intestine. The immune function of colon 26 transplanted in tumor mice was decreased. Additionally, CIK improved the microenvironment of tumor hypoxia and promoted immune reconstitution.

The Critical Role of Proteolytic Relay through Cathepsins B and E in the Phenotypic Change of Microglia/Macrophage

Proteinase cascades are part of the basic machinery of neuronal death pathways. Neuronal cathepsin B (CatB), a typical cysteine lysosomal protease, plays a critical role in neuronal death through lysosomal leakage or excessive autophagy. On the other hand, much attention has been paid to microglial CatB in neuronal death. We herein show the critical role of proteolytic relay through microglial CatB and CatE in the polarization of microglia/macrophages in the neurotoxic phenotype, leading to hypoxia/ischemia (HI)-induced hippocampal neuronal damage in neonatal mice. HI caused extensive brain injury in neonatal wild-type mice, but not in CatB(-/-) mice. Furthermore, HI-induced polarization of microglia/macrophages in the neurotoxic phenotype followed by the neuroprotective phenotype in wild-type mice. On the other hand, microglia/macrophages exhibited only the early and transient polarization in the neuroprotective phenotype in CatB(-/-) mice. CA-074Me, a specific CatB inhibitor, significantly inhibited the neuronal death of primary cultured hippocampal neurons induced by the conditioned medium from cultured microglia polarized in the neurotoxic phenotype. Furthermore, CA-074Me prevented the activation of nuclear factor-κB (NF-κB) in cultured microglia by inhibiting autophagic inhibitor of κBα degradation following exposure to oxygen-glucose deprivation. Rather surprisingly, CatE increased the CatB expression after HI by the liberation of the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) from microglia through the proteasomal pathway. A significant increase in CatB and CatE levels was found exclusively in microglia/macrophages after HI. Thus, a proteolytic relay through the early CatE/TRAIL-dependent proteosomal and late CatB-dependent autophagic pathways for NF-κB activation may play a critical role in the polarization of microglia/macrophages in the neurotoxic phenotype. Significance statement: Proteinase cascades are part of the basic machinery of neuronal death pathways. Cathepsin B, a typical cysteine lysosomal protease, plays a critical role in neuronal death through lysosomal leakage or excessive autophagy in neurons. On the other hand, much attention has been also paid to the role of microglial cathepsin B in neuronal death. In this study, using in vivo and in vitro models of relevance to brain ischemia, we found a critical role of proteolytic relay through cathepsin B and cathepsin E in the neurotoxic polarization of microglia/macrophages, which is responsible for aggravation of hypoxia/ischemia-induced neuronal injury. These findings suggest orally active selective inhibitors of cathepsin B or cathepsin E as promising pharmacological agents for the treatment of ischemic brain injury.

The MSHA strain of Pseudomonas aeruginosa (PA-MSHA) inhibits gastric carcinoma progression by inducing M1 macrophage polarization

Macrophages play crucial roles in promoting tumor development and progression. In the present study, we found that the mannose-sensitive hemagglutination pilus strain of Pseudomonas aeruginosa (PA-MSHA) was efficient in inducing M1 macrophage polarization. PA-MSHA treatment increases expression of M1-related cytokines and promotes activation of murine peritoneal macrophages (MPM). Interestingly, PA-MSHA inhibits cell proliferation and migration and induces the apoptosis of gastric carcinoma cells. These effects of PA-MSHA on M1 polarization were associated with activation of NF-κB expression. Thus, inducing polarization of M1 by PA-MSHA may be one potential strategy for inhibiting gastric carcinoma progression in mice.

Autophagy-induced RelB/p52 activation mediates tumour-associated macrophage repolarisation and suppression of hepatocellular carcinoma by natural compound baicalin

The plasticity of tumour-associated macrophages (TAMs) has implicated an influential role in hepatocellular carcinoma (HCC). Repolarisation of TAM towards M1 phenotype characterises an immune-competent microenvironment that favours tumour regression. To investigate the role and mechanism of TAM repolarisation in suppression of HCC by a natural compound baicalin, Orthotopic HCC implantation model was used to investigate the effect of baicalin on HCC; liposome-clodronate was introduced to suppress macrophage populations in mice; bone marrow-derived monocytes (BMDMs) were induced to unpolarised, M1-like, M2-like macrophages and TAM using different conditioned medium. We observed that oral administration of baicalin (50 mg/kg) completely blocked orthotopic growth of implanted HCC. Suppression of HCC by baicalin was diminished when mice macrophage was removed by clodronate treatment. Baicalin induced repolarisation of TAM to M1-like phenotype without specific toxicity to either phenotype of macrophages. Baicalin initiated TAM reprogramming to M1-like macrophage, and promoted pro-inflammatory cytokines production. Co-culturing of HCC cells with baicalin-treated TAMs resulted in reduced proliferation and motility in HCC. Baicalin had minimal effect on derivation of macrophage polarisation factors by HCC cells, while directly induced repolarisation of TAM and M2-like macrophage. This effect was associated with elevated autophagy, and transcriptional activation of RelB/p52 pathway. Suppression of autophagy or RelB abolished skewing of baicalin-treated TAM. Autophagic degradation of TRAF2 in baicalin-treated TAM might be responsible for RelB/p52 activation. Our findings unveil the essential role of TAM repolarisation in suppressive effect of baicalin on HCC, which requires autophagy-associated activation of RelB/p52.

Tim-3 fosters HCC development by enhancing TGF-β-mediated alternative activation of macrophages

OBJECTIVE

Tumour-associated macrophages (TAMs) and their alternative activation contribute greatly to the development of hepatocellular carcinoma (HCC). Tim-3 is highly expressed on macrophages and regulates macrophage functions in several conditions. However, whether Tim-3 is involved in the activation and the function of TAMs has not been reported.

DESIGN

Tim-3 expression in HCC samples was evaluated by flow cytometry, immunohistochemistry and confocal analysis. We analysed the effects of Tim-3 knockdown on macrophages in growth of H22 tumour homografts in BALB/c mice. Tim-3 interference was performed by neutralising antibody, small interfering RNA or short hairpin RNA-expressing lentivirus. Cytokine production was evaluated by reverse transcription PCR, ELISA or Cytometric Bead Array. The effects of Tim-3 interference in macrophages were examined with regard to alternative activation of macrophages and proliferation and migration of Hepa1-6 cells. Cell growth curve, colony formation and transwell assays were involved to estimate cell proliferation and migration.

RESULTS

Tim-3 expression was significantly increased in both peripheral blood monocytes and TAMs in patients with HCC. The Tim-3 expression in monocytes/TAMs strongly correlated with higher tumour grades and the poor survival of patients with HCC. Consistently, HCC conditioned medium or transforming growth factor-β fostered Tim-3 expression and the alternative activation of macrophages. Moreover, Tim-3 interference in macrophages significantly inhibited the alternative activation of macrophages and suppressed HCC cell growth both in vitro and in vivo. Blocking interleukin 6 reversed the Tim-3-mediated effects on HCC cell growth in vitro.

CONCLUSIONS

Tim-3 displays critical roles in microenvironment-induced activation and protumoral effects of TAMs in HCC. Interference of Tim-3 might be great potential in HCC therapy.

Circulating IL-33 level is associated with the progression of lung cancer

OBJECTIVES

Interleukin (IL)-33 protects against infection and inflammation; however, few studies have explored the relevance of IL-33 in lung cancer patients. We evaluated relation of plasma IL-33 levels with development and progression of lung cancer.

MATERIALS AND METHODS

A total of 160 patients with lung cancer and 160 controls with normal lungs were enrolled. Plasma IL-33 levels were measured using a specific sandwich ELISA; these levels were followed-up in 18 patients who underwent surgery and in 14 patients treated with chemotherapy. Malignant lesions and normal lung tissues from 10 cancer patients were subjected to immunohistochemical staining for IL-33.

RESULTS

IL-33 levels were significantly lower in cancer patients than normal controls (0.08 vs. 0.38 ng/mL, p=0.005). Among cancer patients, IL-33 decreased in a stage-dependent manner from 0.76 ng/mL in stage I patients to 0.25 ng/mL in those with stage II, 0.08 ng/mL in those with stage III, and 0.08 ng/mL in those with stage IV (p=0.002). The levels were higher at stage I (p=0.041) and markedly lower at stages III and IV than those of controls (p=0.005 and p=0.001, respectively). A similar pattern was observed when IL-33 levels were analyzed by T stage; the levels were 0.39 ng/mL at T1/T2 vs. 0.08 ng/mL at T3/T4 (p=0.001). However, no difference was noted when stage N1 levels were compared with N2 and N3 levels (p=0.058), or between stage M0 and M1 levels (p=0.147). IL-33 levels gradually decreased after surgical resection of malignant lesions (from 1.075 to 0.756 ng/mL, p=0.006), but were unchanged after chemotherapy (0.705 vs. 0.829 ng/mL, p=0.875). On immunohistochemical staining, bronchial epithelial and vascular endothelial cells of normal lung tissues mainly expressed IL-33.

CONCLUSIONS

Plasma IL-33 levels are associated inversely with progression of lung cancer. The observed decreases may be attributed to lung volume reduction containing bronchial epithelium and vascular endothelium as the sources of IL-33.

Efficacy and safety of sorafenib for treatment of Japanese metastatic renal cell carcinoma patients undergoing hemodialysis

BACKGROUND

Little information has been published on the use of tyrosine kinase inhibitors for treatment of patients undergoing hemodialysis (HD). We investigated the efficacy and safety of sorafenib for metastatic renal cell carcinoma (mRCC) patients undergoing HD.

METHODS

Twenty patients undergoing HD were treated with sorafenib as first-line therapy for mRCC at our hospital between April 2008 and August 2014. Patient medical records were retrospectively reviewed to evaluate the response to sorafenib and treatment-related toxicity.

RESULTS

Fifteen and 5 patients were classified in the intermediate and poor risk groups, respectively, of the Memorial Sloan-Kettering Cancer Center risk model. Eighteen patients had 3 or more metastatic lesions, and 7 patients had metastases in 2 or more organs. Of 16 patients who had previously undergone nephrectomy, 8 were pathologically diagnosed with non-clear-cell carcinoma. The median duration of sorafenib therapy was 4.7 months. Sorafenib was discontinued owing to progressing disease for 15 patients and because of serious adverse events (AE) (≥grade 3) for 4 patients, i.e. subarachnoid hemorrhage, cerebral hemorrhage, sepsis, and syncope for 1 patient each. Median time to progression was 6.3 months, and median overall survival was 14.2 months.

CONCLUSIONS

In this study, many patients had unfavorable clinical features, for example poor risk classification and metastases in multiple organs. Although sorafenib treatment of HD patients seems feasible, careful monitoring is needed because of the tendency for a high incidence of serious AE, even when a reduced dose is administered.

Expression of Sox2 in breast cancer cells promotes the recruitment of M2 macrophages to tumor microenvironment

Transcriptional factor Sox2 promotes tumor metastasis; however its regulatory effect on tumor-associated macrophages (TAMs, M2 phenotype) has not been defined. This study disclosed concomitant expression of TAMs marker-CD163 with SOX2 in human breast cancer and showed that Sox2 in breast cancer cells promotes recruitment of TAMs with altered expression of multiple chemokines, including MIP-1α, ICAM-1 etc. and activation of Stat3 and NF-κB signalings. In addition, TAMs rescued the compromised lung metastasis induced by Sox2 silencing in breast cancer cells. Together, this study documented that Sox2 plays an important role in recruiting TAMs and promotes tumor metastasis in a TAMs dependent manner.

Anti-inflammatory effect of methylpenicinoline from a marine isolate of Penicillium sp. (SF-5995): inhibition of NF-κB and MAPK pathways in lipopolysaccharide-induced RAW264.7 macrophages and BV2 microglia

In the course of a search for anti-inflammatory metabolites from marine-derived fungi, methylpenicinoline (1) was isolated from a marine isolate of Penicillin sp. Compound 1 inhibited lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production by suppressing the expression of inducible NO synthase (iNOS) in RAW264.7 macrophages and BV2 microglia. It also attenuated prostaglandin E₂ (PGE₂) production by suppressing cyclooxygenase-2 (COX-2) expression in a concentration-dependent manner (from 10 μM to 80 μM) without affecting cell viability. In addition, compound 1 reduced the production of the pro-inflammatory cytokine interleukin-1β (IL-1β). In a further study designed to elucidate the mechanism of its anti-inflammatory effects, compound 1 was shown to block nuclear factor-kappa B (NF-κB) activation in LPS-induced RAW264.7 macrophages and BV2 microglia by inhibiting the phosphorylation of inhibitor kappa B-α (IκB-α), thereby suppressing the nuclear translocation of NF-κB dimers, namely p50 and p65, that are known to be crucial molecules associated with iNOS and COX-2 expression. In addition, compound 1 inhibited the activation of mitogen-activated protein kinase (MAPK) pathways. Taken together, the results suggest that compound 1 might be a valuable therapeutic agent for the treatment of anti-inflammatory and anti-neuroinflammatory diseases.

A novel systems pharmacology model for herbal medicine injection: a case using Reduning injection

BACKGROUND

Compared with the traditional oral administration form, injection administration is basically superior in terms of both biological availability and therapeutic effects. However, few researches have focused on the traditional Chinese medicinal injection due to the complicated constituents and the intricate mechanism of action.

METHODS

In the present work, a novel systems pharmacology model, integrating ADME (absorption, distribution, metabolism, and excretion) filtering such as half-life evaluation, network targeting, pathway and systems analyses, is specifically developed for the identification of active compounds and the study of the mechanism of action of TCM injection, which is exemplified by Reduning injection confronting the influenza.

RESULTS

The ADME filter successfully identifies 35 bioactive compounds (31 molecules and 4 metabolites) from the Reduning injection. The systems analysis and experimental validation further reveal a new way of confronting influenza disease of this injection: 1) stimulating the immunomodulatory agents for immune response activation, and 2) regulating the inflammatory agents for anti-inflammation.

CONCLUSIONS

The novel systems pharmacology method used in this study has the potential to advance the understanding of the molecular mechanisms of action of multicomponent herbal injections, and provide clues to discovering more effective drugs against complex diseases.

Glioblastoma stem cells: new insights in therapeutic strategies

ABSTRACT 

Despite notable achievements in glioblastoma diagnosis and treatment, the prognosis of glioblastoma patients remains poor and reflects the failure of current therapeutic modalities. In this context, innovative therapeutic strategies have recently been developed to specifically target glioblastoma stem cells, a subpopulation of tumor cells involved in experimental tumorigenesis and known to be critical for tumor recurrence and therapeutic resistance. The current review summarizes the different trails which make glioblastoma stem cells resistant to treatments, mainly focusing on radio-, chemo- and immunotherapy. This broad overview might actually help to set up new bases for glioblastoma therapy in order to better fight tumor relapses and to improve the patients’ prognosis.

Preoperative C-reactive protein in the serum: a prognostic biomarker for upper urinary tract urothelial carcinoma treated with radical nephroureterectomy

OBJECTIVE

To investigate the impact of preoperative serum C-reactive protein (CRP) on clinicopathological features and prognosis in patients with upper tract urothelial cancer (UTUC) after radical nephroureterectomy (RNU).

PATIENTS AND METHODS

Data of 265 patients from three German centers who underwent RNU for UTUC without neoadjuvant chemotherapy between 1990 and 2012 were evaluated. Mean follow-up was 37 months (interquartile range 9-48). CRP was analyzed as a categorical and continuous variable for the prediction of recurrence-free survival (RFS), disease-specific survival (DSS) and all-cause survival (ACS) using uni- and multivariate Cox regression analyses.

RESULTS

The optimal cutoff for CRP was calculated by the Youden index at 0.90 mg/dl. Elevated CRP was significantly associated with pT3/4 and pN+ in a preoperative model including age, gender, tumor multifocality, tumor localization and the Eastern Cooperative Oncology Group Performance Status. In a multivariable Cox regression model adjusted for features significant in univariable analysis, categorized and continuous CRP levels were both independent predictors for RFS [hazard ratio (HR) 1.18, p = 0.050; HR 1.03, p = 0.012] and DSS (HR 1.61, p = 0.026; HR 1.06, p = 0.001). Continuous CRP was an independent predictor for ACS (HR 1.05, p = 0.036).

CONCLUSIONS

Elevated preoperative CRP is significantly associated with aggressive tumor biology and an independent predictor for poor survival after RNU. Preoperative serum CRP represents an easily obtainable and cost-effective marker in UTUC and may help in counseling patients with regard to operative management and/or adjuvant or neoadjuvant therapies.

Antitumor effect of nuclear factor-κB decoy transfer by mannose-modified bubble lipoplex into macrophages in mouse malignant ascites

Patients with malignant ascites (MAs) display several symptoms, such as dyspnea, nausea, pain, and abdominal tenderness, resulting in a significant reduction in their quality of life. Tumor-associated macrophages (TAMs) play a crucial role in MA progression. Because TAMs have a tumor-promoting M2 phenotype, conversion of the M2 phenotypic function of TAMs would be promising for MA treatment. Nuclear factor-κB (NF-κB) is a master regulator of macrophage polarization. Here, we developed targeted transfer of a NF-κB decoy into TAMs by ultrasound (US)-responsive, mannose-modified liposome/NF-κB decoy complexes (Man-PEG bubble lipoplexes) in a mouse peritoneal dissemination model of Ehrlich ascites carcinoma. In addition, we investigated the effects of NF-κB decoy transfection into TAMs on MA progression and mouse survival rates. Intraperitoneal injection of Man-PEG bubble lipoplexes and US exposure transferred the NF-κB decoy into TAMs effectively. When the NF-κB decoy was delivered into TAMs by this method in the mouse peritoneal dissemination model, mRNA expression of the Th2 cytokine interleukin (IL)-10 in TAMs was decreased significantly. In contrast, mRNA levels of Th1 cytokines (IL-12, tumor necrosis factor-α, and IL-6) were increased significantly. Moreover, the expression level of vascular endothelial growth factor in ascites was suppressed significantly, and peritoneal angiogenesis showed a reduction. Furthermore, NF-κB decoy transfer into TAMs significantly decreased the ascitic volume and number of Ehrlich ascites carcinoma cells in ascites, and prolonged mouse survival. In conclusion, we transferred a NF-κB decoy efficiently by Man-PEG bubble lipoplexes with US exposure into TAMs, which may be a novel approach for MA treatment.

Response gene to complement 32 protein promotes macrophage phagocytosis via activation of protein kinase C pathway

Macrophage phagocytosis plays an important role in host defense. The molecular mechanism, especially factors regulating the phagocytosis, however, is not completely understood. In the present study, we found that response gene to complement 32 (RGC-32) is an important regulator of phagocytosis. Although RGC-32 is induced and abundantly expressed in macrophage during monocyte-macrophage differentiation, RGC-32 appears not to be important for this process because RGC-32-deficient bone marrow progenitor can normally differentiate to macrophage. However, both peritoneal macrophages and bone marrow-derived macrophages with RGC-32 deficiency exhibit significant defects in phagocytosis, whereas RGC-32-overexpressed macrophages show increased phagocytosis. Mechanistically, RGC-32 is recruited to macrophage membrane where it promotes F-actin assembly and the formation of phagocytic cups. RGC-32 knock-out impairs F-actin assembly. RGC-32 appears to interact with PKC to regulate PKC-induced phosphorylation of F-actin cross-linking protein myristoylated alanine-rich protein kinase C substrate. Taken together, our results demonstrate for the first time that RGC-32 is a novel membrane regulator for macrophage phagocytosis.

Calorie restriction decreases murine and human pancreatic tumor cell growth, nuclear factor-κB activation, and inflammation-related gene expression in an insulin-like growth factor-1-dependent manner

Calorie restriction (CR) prevents obesity and has potent anticancer effects that may be mediated through its ability to reduce serum growth and inflammatory factors, particularly insulin-like growth factor (IGF)-1 and protumorigenic cytokines. IGF-1 is a nutrient-responsive growth factor that activates the inflammatory regulator nuclear factor (NF)-κB, which is linked to many types of cancers, including pancreatic cancer. We hypothesized that CR would inhibit pancreatic tumor growth through modulation of IGF-1-stimulated NF-κB activation and protumorigenic gene expression. To test this, 30 male C57BL/6 mice were randomized to either a control diet consumed ad libitum or a 30% CR diet administered in daily aliquots for 21 weeks, then were subcutaneously injected with syngeneic mouse pancreatic cancer cells (Panc02) and tumor growth was monitored for 5 weeks. Relative to controls, CR mice weighed less and had decreased serum IGF-1 levels and smaller tumors. Also, CR tumors demonstrated a 70% decrease in the expression of genes encoding the pro-inflammatory factors S100a9 and F4/80, and a 56% decrease in the macrophage chemoattractant, Ccl2. Similar CR effects on tumor growth and NF-κB-related gene expression were observed in a separate study of transplanted MiaPaCa-2 human pancreatic tumor cell growth in nude mice. In vitro analyses in Panc02 cells showed that IGF-1 treatment promoted NF-κB nuclear localization, increased DNA-binding of p65 and transcriptional activation, and increased expression of NF-κB downstream genes. Finally, the IGF-1-induced increase in expression of genes downstream of NF-κB (Ccdn1, Vegf, Birc5, and Ptgs2) was decreased significantly in the context of silenced p65. These findings suggest that the inhibitory effects of CR on Panc02 pancreatic tumor growth are associated with reduced IGF-1-dependent NF-κB activation.

Targeting colon cancer cell NF-κB promotes an anti-tumour M1-like macrophage phenotype and inhibits peritoneal metastasis

In a model of peritoneal metastasis in immune-competent mice, we show that nuclear factor (NF)-κB inhibition in CT26 colon cancer cells prevents metastasis. NF-κB inhibition, by stable overexpression of IκB-α super-repressor, induced differential polarization of co-cultured macrophages to an M1-like anti-tumour phenotype in vitro. NF-κB-deficient cancer cell-conditioned media (CT26/IκB-α SR) induced interleukin (IL)-12 and nitric oxide (NO) synthase (inducible NO synthase (iNOS)) expression in macrophages. Control cell (CT26/EV) conditioned media induced high levels of IL-10 and arginase in macrophages. In vivo, this effect translated to reduction in metastasis in mice injected with CT26/ IκB-α SR cells and was positively associated with increased CD8(+)CD44(+)CD62L(-) and CD4(+)CD44(+)CD62L(-) effector T cells. Furthermore, inhibition of NF-κB activity induced high levels of NO in infiltrating immune cells and decreases in matrix metalloproteinase-9 expression, simultaneous with increases in tissue inhibitor of metalloproteinases 1 and 2 within tumours. CT26/IκB-α SR tumours displayed increased pro-inflammatory gene expression, low levels of angiogenesis and extensive intratumoral apoptosis, consistent with the presence of an anti-tumour macrophage phenotype. Macrophage depletion reduced tumour size in CT26/EV-injected animals and increased tumour size in CT26/IκB-α SR cells compared with untreated tumours. Our data demonstrate, for the first time, that an important implication of targeting tumour cell NF-κB is skewing of macrophage polarization to an anti-tumour phenotype. This knowledge offers novel therapeutic opportunities for anticancer treatment.

Tumour-associated macrophages targeted transfection with NF-κB decoy/mannose-modified bubble lipoplexes inhibits tumour growth in tumour-bearing mice

Tumour-associated macrophages (TAM) exhibit an M2 phenotype that promotes tumour progression, and conversion of M2 TAM toward a tumouricidal M1 phenotype is a promising anti-cancer therapy. As NF-κB is a key regulator of macrophage polarization, we developed an in vivo TAM-targeting delivery system that combines mannose-modified bubble liposomes/NF-κB decoy complexes (Man-PEG bubble lipoplexes) and ultrasound (US) exposure. We investigated the effects of NF-κB decoy transfection on TAM phenotype in solid tumour-bearing mice. Post-transfection tumour growth and survival rates were also recorded. Th2 cytokine (IL-10) level in TAM was significantly lower by NF-κB decoy transfection using Man-PEG bubble lipoplexes and US exposure, while Th1 cytokine levels (IL-1β, TNF-α and IL-6) were significantly higher when compared with controls. In addition, mRNA levels of vascular endothelial growth factor, matrix metalloproteinase-9 and arginase were significantly lower in TAM post-NF-κB decoy transfection. Importantly, TAM-targeted NF-κB decoy transfection inhibited tumour growth and prolonged survival rates in mice. Therefore, TAM-targeted NF-κB decoy transfection using Man-PEG bubble lipoplexes and US exposure may be an effective approach for anti-cancer therapy based on TAM phenotypic conversion from M2 toward M1.

Chromatin immunoprecipitation analysis of bortezomib-mediated inhibition of NFκB recruitment to IL-1β and TNFα gene promoters in human macrophages

Interleukin-1β (IL-1) and tumor necrosis factor-α (TNF) are important pro-inflammatory cytokines involved in the mediation of the immune response, inflammation, tissue repair, and tumor progression. Regulation of IL-1 and TNF expression is mediated at the level of transcription by the transcription factor NFκB. Inhibition of NFκB activity by the proteasome inhibitor bortezomib (BZ) has been used as a frontline therapy in multiple myeloma and other hematological malignancies. In this chapter, we describe a protocol that uses chromatin immunoprecipitation (ChIP) to analyze the NFκB recruitment to endogenous IL-1 and TNF promoters in BZ-treated human macrophages. Corresponding to the BZ-suppressed mRNA levels of IL-1 and TNF, we show that BZ inhibits p65 NFκB recruitment to IL-1 and TNF promoters. This study specifically uses U937 macrophages, but the protocol could be easily modified to analyze the regulation of NFκB recruitment in other cell types.

Autophagy-mediated regulation of macrophages and its applications for cancer

Autophagy is a highly conserved homeostatic pathway that plays an important role in tumor development and progression by acting on cancer cells in a cell-autonomous mechanism. However, the solid tumor is not an island, but rather an ensemble performance that includes nonmalignant stromal cells, such as macrophages. A growing body of evidence indicates that autophagy is a key component of the innate immune response. In this review, we discuss the role of autophagy in the control of macrophage production at different stages (including hematopoietic stem cell maintenance, monocyte/macrophage migration, and monocyte differentiation into macrophages) and polarization and discuss how modulating autophagy in tumor-associated macrophages (TAMs) may represent a promising strategy for limiting cancer growth and progression.

Hypoxia: how does the monocyte-macrophage system respond to changes in oxygen availability?

Hypoxia is an important feature of inflamed tissue, such as the RA joint. Activated monocytes/macrophages and endothelial cells play a pivotal role in the pathogenesis of RA, implicated in the mechanism of inflammation and erosion. During development, myeloid progenitor cells sequentially give rise to monoblasts, promonocytes, and monocytes that are released from the bone marrow into the bloodstream. After extravasation, monocytes differentiate into long-lived, tissue-specific macrophages or DCs. The effect of different oxygen concentrations experienced by these cells during maturation represents a novel aspect of this developmental process. In inflamed joint tissue, the microvascular architecture is highly dysregulated; thus, efficiency of oxygen supply to the synovium is poor. Therefore, invading cells must adapt instantaneously to changes in the oxygen level of the microenvironment. Angiogenesis is an early event in the inflammatory joint, which is important in enabling activated monocytes to enter via endothelial cells by active recruitment to expand the synovium into a "pannus", resulting in cartilage degradation and bone destruction. The increased metabolic turnover of the expanding synovial pannus outpaces the dysfunctional vascular supply, resulting in hypoxia. The abnormal bioenergetics of the microenvironment further promotes synovial cell invasiveness. In RA, joint hypoxia represents a potential threat to cell function and survival. Notably, oxygen availability is a crucial parameter in the cellular energy metabolism, itself an important factor in determining the function of immune cells.

In vitro evaluation of inhibitory effect of nuclear factor-kappaB activity by small interfering RNA on pro-tumor characteristics of M2-like macrophages

Tumor-associated macrophages (TAMs) have an alternatively activated macrophage phenotype (M2) and promote cancer cell proliferation, angiogenesis and metastasis. Nuclear factor-kappaB (NF-κB) is one of the master regulators of macrophage polarization. Here, we investigated the effect of inhibition of NF-κB activity by small interfering RNA (siRNA) on the pro-tumor response of macrophages located in the tumor microenvironment in vitro. We used mouse peritoneal macrophages cultured in conditioned medium from colon-26 cancer cells as an in vitro TAM model (M2-like macrophages). Transfection of NF-κB (p50) siRNA into M2-like macrophages resulted in a significant decrease in the secretion of interleukin (IL)-10 (a T helper 2 (Th2) cytokine) and a significant increase of T helper 1 (Th1) cytokine production (IL-12, tumor necrosis factor-α, and IL-6). Furthermore, vascular endothelial growth factor production and matrix metalloproteinase-9 mRNA expression in M2-like macrophages were suppressed by inhibition of NF-κB expression with NF-κB (p50) siRNA. In addition, there was a reduction of arginase mRNA expression and increase in nitric oxide production. The cytokine secretion profiles of macrophages cultured in conditioned medium from either B16BL6 or PAN-02 cancer cells were also converted from M2 to classically activated (M1) macrophages by transfection of NF-κB (p50) siRNA. These results suggest that inhibition of NF-κB activity in M2-like macrophages alters their phenotype toward M1.

Vermelhotin, an anti-inflammatory agent, suppresses nitric oxide production in RAW 264.7 cells via p38 inhibition

Vermelhotin exhibited potential anti-inflammatory activity through inhibition of nitric oxide production (IC₅₀ = 5.35 ± 0.59 μM) in LPS-stimulated RAW 264.7 macrophage cells. Vermelhotin suppressed expression of inducible nitric oxide synthase (iNOS) at mRNA and protein levels, in a dose-dependent manner. Mechanistic studies revealed that vermelhotin abrogated upstream signaling of iNOS expression by selectively inhibiting p38 phosphorylation, while ERK and JNK activations were not affected.

The invisible arm of immunity in common cancer chemoprevention agents

Immunoprevention refers to a strategy of preventing pathogen-associated and spontaneous cancers through the use of vaccines, antibodies, and immune modulators. Immune modulators function by enhancing the endogenous ability of the immune system to monitor for malignancy, so-called "immunosurveillance." There is growing evidence that many of the most promising cancer chemoprevention agents including aspirin, COX-2 inhibitors, aromatase inhibitors, and bisphosphonates mediate their effects, in part, by enhancing immunosurveillance and reversing the immune evasive mechanisms that premalignant lesions use. In the following review, we introduce critical components of the human immune surveillance system-dendritic cells, T cells, and immune suppressive cells-and discuss the emerging data suggesting that common chemoprevention agents may modulate the function of these immunologic cells.

Glioma stem cells and immunotherapy for the treatment of malignant gliomas

Stem cell research has led to the discovery of glioma stem cells (GSCs), and because these cells are resistant to chemotherapy and radiotherapy, analysis of their properties has been rapidly pursued for targeted treatment of malignant glioma. Recent studies have also revealed complex crosstalk between GSCs and their specialized environment (niche). Therefore, targeting not only GSCs but also their niche may be a principle for novel therapies of malignant glioma. One possible novel strategy for targeting GSCs and their niches is immunotherapy with different antitumor mechanism(s) from those of conventional therapy. Recent clinical studies of immunotherapy using peptide vaccines and antibodies have shown promising results. This review describes the recent findings related to GSCs and their niches, as well as immunotherapies for glioma, followed by discussion of immunotherapies that target GSCs for the treatment of malignant glioma.

Tumor microenvironment profoundly modifies functional status of macrophages: peritoneal and tumor-associated macrophages are two very different subpopulations

Macrophages are key players in the inflammatory response. In this study, we tested the hypothesis that although all macrophage subpopulations in tumor hosts are affected by the disease, it is the close proximity to the tumor that induces major alterations in these cells. We compared tumor-associated macrophages (TAMs) with peritoneal macrophages from mice bearing D1-DMBA-3 mammary tumors (T-PEMs). Our results show that TAMs downregulate IL-12p70 but upregulate IL-12p40, IL-23, IL-6 and IL-10. Some NFκB and C/EBP transcription factors family members are decreased in TAMs; however NFκBp50 homodimers, STAT1/pSTAT1 and STAT3/pSTAT3 are overexpressed. Furthermore, while TAMs block T-cell proliferation and are more prone to apoptosis compared to T-PEMs, both types of macrophages have an impaired phagocytic capacity. Moreover, TAMs constitutively express iNOS and produce nitric oxide but do not express arginase and are Gr-1(high) and CD11b(low). Collectively, our analysis of two spatially distinct macrophage subpopulations in tumor-bearing mice revealed that the tumor modulates them differently into two molecularly and functionally dissimilar macrophage subpopulations.

Common mechanisms of dysfunctional adipose tissue and obesity-related cancers

The relation between cancer and metabolic disorders was recognized several decades ago, but the underlying mechanisms involved in cancer development and progression remain obscure. In the last years, many groups have been studying systemic adipose tissue markers in cancer patients. However, few consistent results were obtained. On the other hand, several studies revealed many aspects of adipose tissue physiology in obesity. Nowadays, it is recognized that excessive lipid uptake in adipocytes leads to hypertrophy and consequently to metabolic dysregulation, hypoxia, inflammation, impaired adipocytokine expression and angiogenesis, insulin resistance and macrophage recruitment. In obese patients, tumours commonly colocalize with excessive adipose tissue accumulation, and most of the features of hypertrophic adipose tissue are observed in cancer patients, namely breast and colon. This review aimed to summarize pathological adipose tissue alterations that may contribute to cancer aetiology and development.

Anti-tumour strategies aiming to target tumour-associated macrophages

Tumour-associated macrophages (TAMs) represent a predominant population of inflammatory cells that present in solid tumours. TAMs are mostly characterized as alternatively activated M2-like macrophages and are known to orchestrate nearly all stages of tumour progression. Experimental investigations indicate that TAMs contribute to drug-resistance and radio-protective effects, and clinical evidence shows that an elevated number of TAMs and their M2 profile are correlated with therapy failure and poor prognosis in cancer patients. Recently, many studies on TAM-targeted strategies have made significant progress and some pilot works have achieved encouraging results. Among these, connections between some anti-tumour drugs and their influence on TAMs have been suggested. In this review, we will summarize recent advances in TAM-targeted strategies for tumour therapy. Based on the proposed mechanisms, those strategies are grouped into four categories: (i) inhibiting macrophage recruitment; (ii) suppressing TAM survival; (iii) enhancing M1-like tumoricidal activity of TAMs; (iv) blocking M2-like tumour-promoting activity of TAMs. It is desired that further attention be drawn to this research field and more effort be made to promote TAM-targeted tumour therapy.

Circulating microenvironment of CLL: are nurse-like cells related to tumor-associated macrophages?

B-cell chronic lymphocytic leukemia (B-CLL) is one of the most common hematologic malignancies in Western countries. Accumulation of leukemic lymphocytes in peripheral blood, bone marrow and secondary lymphatic organs of CLL patients is due to decreased apoptosis rather than to increased proliferation. The former is driven by signals from a specific microenvironment, created by stromal cells of mesenchymal origin, follicular dendritic cells, T lymphocytes and others. Nurse-like cells (NLCs) were first described to differentiate from peripheral blood mononuclear cells of CLL patients in vitro, then they have been also found in proliferation centers of their lymphatic tissues. Like tumor-associated macrophages (TAMs) in solid tumors, nurse-like cells promote survival of CLL lymphocytes. NLC gene expression patterns suggest their similarity to TAMs and differ between patients depending on ZAP70 protein expression status. NLC number in vitro corresponds with CD14 expressing cell count and beta-2-microglobulin serum level, and positively correlates with leukemic lymphocyte viability. As NLCs strongly express genes for adhesion molecules and secrete chemokines of antiapoptotic activity, they should be considered as a target for anti-microenvironment therapy of this incurable disease.

TLR2-dependent selective autophagy regulates NF-κB lysosomal degradation in hepatoma-derived M2 macrophage differentiation

Autophagy is a lysosomal pathway for cellular homeostasis control. Both non-selective bulk autophagy and selective autophagy of specific proteins or organelles have been found. Selective autophagy prevents cells from pathogen invasion and stress damage, but its role in regulating transcriptional factors is not clear. Using a macrophage cell differentiation model, the role of autophagy in nuclear factor-κB (NF-κB) regulation is investigated. The bone marrow-derived macrophages (BMDMs) will differentiate into a M2-like phenotype in the presence of hepatoma tumor cell condition medium (CM). The TLR2 signaling drives this M2 polarization and causes NF-κB p65 degradation via lysosome-dependent pathway. The CM-induced ubiquitinated- NF-κB p65 forms aggresome-like structures (ALS) in the cytoplasm of cultured and hepatoma-associated M2 macrophages. This NF-κB p65-contained ALS is recognized by p62/SQSTM1 and degraded by selective autophagy. Treatment with the lysosomal inhibitor bafilomycin A1 or the knockdown of Atg5 can prevent CM-induced NK-κB p65 degradation and induce M2 macrophages to produce a high level of pro-inflammatory cytokines. Furthermore, TLR2 signal induces sustained phosphorylation of extracellular signal-regulated kinase 1/2 to facilitate this autophagy-dependent NF-κB regulation. Our finding provides a novel pathway of NF-κB regulation by p62/SQSTM1-mediated selective autophagy.

Emerging role of the interleukin (IL)-33/ST2 axis in gut mucosal wound healing and fibrosis

Interleukin (IL)-33 (IL-1F11) is the newest member of the IL-1Family of cytokines and has been best characterized as a potent inducer of T helper (Th)2 immune responses. Increasing evidence, however, indicates that IL-33 also represents an important mediator of mucosal healing and epithelial restoration and repair. As such, IL-33 follows the trend of several innate-type cytokines, including members of the IL-1Family (for example, IL-1α, IL-1β, and IL-18), that possess dichotomous roles of inducing a potent proinflammatory response, while also promoting protection and the return to immune homeostasis. This dual function is best depicted in the gut mucosa and is dependent upon the immunological/genetic status of the host and/or the type and phase of the ongoing inflammatory process. IL-33 has also been described as a prototypic 'alarmin' that has the ability to signal local, innate immune responses of trauma or infection in an effort to mount an effective, physiologic inflammatory reaction to induce mucosal healing and restore normal gut equilibrium. Finally, several recent studies have reported the role of IL-33 during fibrogenesis as fibrosis is commonly thought to occur as the end stage of dysregulated wound healing wherein chronic tissue damage is paired with uncontrolled activation of mesenchymal cells. Taken together, aside from its established function of promoting potent Th2 immune responses, IL-33 is emerging as an important cytokine for the induction of mucosal healing and restoration of intestinal homeostasis, as well as playing a central role in fibrosis and wound repair. The present review will focus on what is currently known regarding IL-33's role in gut mucosal wound healing and fibrosis, as well as touch on its potential contribution to tumorigenesis and GI-related cancer, an alternate outcome of dysregulated epithelial proliferation.

microRNA-146a inhibits G protein-coupled receptor-mediated activation of NF-κB by targeting CARD10 and COPS8 in gastric cancer

BACKGROUND

Gastric cancer is the second most common cause of cancer-related death in the world. Inflammatory signals originating from gastric cancer cells are important for recruiting inflammatory cells and regulation of metastasis of gastric cancer. Several microRNAs (miRNA) have been shown to be involved in development and progression of gastric cancer. miRNA-146a (miR-146a) is a modulator of inflammatory signals, but little is known about its importance in gastric cancer. We therefore wanted to identify targets of miR-146a in gastric cancer and examine its biological roles.

RESULTS

The expression of miR-146a was evaluated by quantitative PCR (qPCR) and found up-regulated in the gastrin knockout mice, a mouse model of gastric cancer, and in 73% of investigated human gastric adenocarcinomas. Expression of miR-146a by gastric cancer cells was confirmed by in situ hybridization. Global analysis of changes in mRNA levels after miR-146a transfection identified two transcripts, caspase recruitment domain-containing protein 10 (CARD10) and COP9 signalosome complex subunit 8 (COPS8), as new miR-146a targets. qPCR, Western blotting and luciferase assays confirmed these transcripts as direct miR-146a targets. CARD10 and COPS8 were shown to be part of the G protein-coupled receptor (GPCR) pathway of nuclear factor-kappaB (NF-kappaB) activation. Lysophosphatidic acid (LPA) induces NF-kappaB activation via this pathway and over-expression of miR-146a inhibited LPA-induced NF-kappaB activation, reduced LPA-induced expression of tumor-promoting cytokines and growth factors and inhibited monocyte attraction.

CONCLUSIONS

miR-146a expression is up-regulated in a majority of gastric cancers where it targets CARD10 and COPS8, inhibiting GPCR-mediated activation of NF-kappaB, thus reducing expression of NF-kappaB-regulated tumor-promoting cytokines and growth factors. By targeting components of several NF-kappaB-activating pathways, miR-146a is a key component in the regulation of NF-kappaB activity.

NFκB signaling regulates embryonic and adult neurogenesis

Both embryonic and adult neurogenesis involves the self-renewal/proliferation, survival, migration and lineage differentiation of neural stem/progenitor cells. Such dynamic process is tightly regulated by intrinsic and extrinsic factors and complex signaling pathways. Misregulated neurogenesis contributes much to a large range of neurodevelopmental defects and neurodegenerative diseases. The signaling of NFκB regulates many genes important in inflammation, immunity, cell survival and neural plasticity. During neurogenesis, NFκB signaling mediates the effect of numerous niche factors such as cytokines, chemokines, growth factors, extracellular matrix molecules, but also crosstalks with other signaling pathways such as Notch, Shh, Wnt/β-catenin. This review summarizes current progress on the NFκB signaling in all aspects of neurogenesis, focusing on the novel role of NFκB signaling in initiating early neural differentiation of neural stem cells and embryonic stem cells.

Immune activation in the pathogenesis of treated chronic HIV disease: a workshop summary

With the advent of highly effective antiretroviral therapy (ART), infection with human immunodeficiency virus (HIV) has become a chronic disease rather than a death sentence. Nevertheless, effectively treated individuals have a higher than normal risk for developing noninfectious comorbidities, including cardiovascular and renal disease. Although traditional risk factors of aging as well as treatment toxicity contribute to this risk, many investigators consider chronic HIV-associated inflammation a significant factor in such end-organ disease. Despite effective viral suppression, chronic inflammation persists at levels higher than in uninfected people, yet the stimuli for the inflammation and the mechanism by which inflammation persists and promotes disease pathology remain incompletely understood. This critical gap in scientific understanding complicates and hampers effective decision making about appropriate medical intervention. To better understand the mechanism(s) of chronic immune activation in treated HIV disease, three questions need answers: (1) what is the cause of persistent immune activation during treated HIV infection, (2) what are the best surrogate markers of chronic immune activation in this setting, and (3) what therapeutic intervention(s) could prevent or reverse this process? The NIH sponsored and convened a meeting to discuss the state of knowledge concerning these questions and the best course for developing effective therapeutic strategies. This report summarizes the findings of that NIH meeting.

Tumor-associated macrophages promote angiogenesis and lymphangiogenesis of gastric cancer

BACKGROUND AND OBJECTIVES

This study was conducted to investigate whether and how macrophages recruited to tumor microenvironments (tumor-associated macrophages, TAMs) were involved in angiogenesis and lymphangiogenesis of gastric cancer (GC).

METHODS

TAMs, microvessel density (MVD), and lymphatic vessel density (LVD) in 115 cases of GC tissue were assessed by immunohistochemistry (IHC) staining of CD68, CD34, and D2-40, respectively. Preoperative blood samples from 43 patients were obtained to detect serum levels of vascular endothelial growth factor (VEGF) and VEGF-C. A co-culture system was also developed to study effects and underlying mechanisms of THP-1 macrophages on SGC7901 GC cells.

RESULTS

TAMs numbers were closely related to serosa invasion, lymph node metastasis and tumor, nodes, and metastases stage and a positive correlation existed between the TAMs count and MVD and LVD. Additionally, TAMs were associated with preoperative serum levels of VEGF and VEGF-C, the expression of VEGF and VEGF-C protein in macrophages was up-regulated in the co-culture system, and inhibition of the NF-κB pathway in macrophages induced a significant reduction in the expression of VEGF and VEGF-C in both macrophages and GC cells (all P<0.05).

CONCLUSIONS

TAMs may promote angiogenesis and lymphangiogenesis of GC, possibly by enhancing VEGF and VEGF-C expression.

The immunological contribution of NF-κB within the tumor microenvironment: a potential protective role of zinc as an anti-tumor agent

Over decades, cancer treatment has been mainly focused on targeting cancer cells and not much attention to host tumor microenvironment. Recent advances suggest that the tumor microenvironment requires in-depth investigation for understanding the interactions between tumor cell biology and immunobiology in order to optimize therapeutic approaches. Tumor microenvironment consists of cancer cells and tumor associated reactive fibroblasts, infiltrating non-cancer cells, secreted soluble factors or molecules, and non-cellular support materials. Tumor associated host immune cells such as Th(1), Th(2), Th17, regulatory cells, dendritic cells, macrophages, and myeloid-derived suppressor cells are major components of the tumor microenvironment. Accumulating evidence suggests that these tumor associated immune cells may play important roles in cancer development and progression. However, the exact functions of these cells in the tumor microenvironment are poorly understood. In the tumor microenvironment, NF-κB plays an important role in cancer development and progression because this is a major transcription factor which regulates immune functions within the tumor microenvironment. In this review, we will focus our discussion on the immunological contribution of NF-κB in tumor associated host immune cells within the tumor microenvironment. We will also discuss the potential protective role of zinc, a well-known immune response mediator, in the regulation of these immune cells and cancer cells in the tumor microenvironment especially because zinc could be useful for conditioning the tumor microenvironment toward innovative cancer therapy.

Immunology in the clinic review series; focus on cancer: tumour-associated macrophages: undisputed stars of the inflammatory tumour microenvironment

Mononuclear phagocytes are cells of the innate immunity that defend the host against harmful pathogens and heal tissues after injury. Contrary to expectations, in malignancies, tumour-associated macrophages (TAM) promote disease progression by supporting cancer cell survival, proliferation and invasion. TAM and related myeloid cells [Tie2(+) monocytes and myeloid-derived suppressor cells (MDSC)] also promote tumour angiogenesis and suppress adaptive immune responses. These divergent biological activities are mediated by macrophages/myeloid cells with distinct functional polarization, which are ultimately dictated by microenvironmental cues. Clinical and experimental evidence has shown that cancer tissues with high infiltration of TAM are associated with poor patient prognosis and resistance to therapies. Targeting of macrophages in tumours is considered a promising therapeutic strategy: depletion of TAM or their 're-education' as anti-tumour effectors is under clinical investigation and will hopefully contribute to the success of conventional anti-cancer treatments.

Macrophages are important mediators of either tumor- or inflammation-induced lymphangiogenesis

The lymphatic system provides important functions for tissue fluid homeostasis and immune response. Lymphangiogenesis, the formation of new lymphatics, comprises a series of complex cellular events in vitro or in vivo, e.g., proliferation, differentiation, and sprouting. Recent evidence has implied that macrophages act as a direct structural contributor to lymphatic endothelial walls or secret VEGF-C/-D and VEGF-A to initiate lymphangiogenesis in inflamed or tumor tissues. Bone marrow-derived macrophages are versatile cells that express different functional programs in response to exposure to microenvironmental signals, and can be identified by specific expression of a number of proteins, F4/80, CD11b, and CD68. Several causative factors, e.g., NF-κB, IL-1β, TNF-α, SDF-1, M-CSF, especially TonEBP/VEGF-C signaling, may be actively involved in macrophage-induced lymphangiogenesis. Alteration of macrophage phenotype and function has a profound effect on the development and progression of inflammation and malignancy, and macrophage depletion for controlling lymphangiogenesis may provide a novel approach for prevention and treatment of lymphatic-associated diseases.