Role Of Monocyte Chemotactic Protein-1 Research Articles

Beneficial effects of the naturally occurring flavonoid silibinin on the prostate cancer microenvironment: role of monocyte chemotactic protein-1 and immune cell recruitment.

Tumor microenvironment plays an essential role in prostate carcinogenesis and offers novel opportunities to prevent and treat prostate cancer (PCA). Here, we investigated the ability of cancer-associated fibroblasts (CAFs) to promote PCA progression, and silibinin efficacy to target this response. We collected conditioned media from CAFs treated with vehicle or silibinin, and labeled as control conditioned media (CCM) or silibinin-treatment conditioned media (SBCM), respectively. Next, we characterized the effect of CCM and SBCM treatment in several PCA cell lines (RWPE-1, WPE-1 NA-22, WPE-1 NB-14 and PC3). Result showed that compared with SBCM, CCM significantly reduces E-cadherin expression and increases invasiveness and clonogenicity in PCA cells. Further molecular studies identified monocyte chemotactic protein-1 (MCP-1) as the key component of CCM that promotes PCA invasiveness, whereas silibinin treatment strongly reduced MCP-1 expression in CAFs by inhibiting the DNA-binding activity of MCP-1 transcriptional regulators-nuclear factor-kappaB and AP-1. In vivo, silibinin feeding (200mg/kg body weight) strongly reduced TRAMPC1 allografts growth (by 68%) in syngeneic C57Bl/6 mice. TRAMPC1 tumor analysis showed that silibinin reduced MCP-1 and CAFs' biomarkers (fibroblast activation protein, α-smooth muscle actin, transforming growth factor beta 2, vimentin etc.) and significantly modulated the recruitment of immune cells in the tumor microenvironment. Similar inhibitory effects of silibinin on MCP-1 and immune cells recruitment were also observed in TRAMP PCA tissues with reported silibinin efficacy. Overall, our data suggest that silibinin can target CAF-mediated invasiveness in PCA by inhibiting MCP-1 secretion. This, in turn, was associated with a reduction in immune cell recruitment in vivo along with a marked reduction in tumor growth.

Abstract 435: Adipocyte-derived monocyte chemotactic protein-1 (MCP-1) promotes prostate cancer progression through matrix metalloproteinase (MMP-2) mediated extracellular matrix degradation

Abstract Background: Obesity is known to be associated with prostate cancer development and progression, but the detailed mechanism is not clear. Monocyte chemotactic protein-1 (MCP-1) is secreted from cancer cells, stromal cells and adipocytes, and it is involved in prostate cancer progression. Here we investigated the biological role of MCP-1 secreted from adipocytes for prostate cancer cells. Methods: Human pre-adipocytes (HPAds) were cultured and differentiated to mature adipocytes. Conditioned medium (CM) from HPAd cells was obtained using phenol red-free RPMI1640 medium. We performed a cytokine membrane array analysis to detect cytokines in the CM. To characterize the physiological function of MCP-1 in the CM, we performed an MTT-assay, a wound-healing and invasion assay with anti-MCP-1 antibody using three prostate cancer cell lines: DU145, LNCaP, and PC-3. Matrix metalloproteinase (MMP)-2 and MMP-9 activities were evaluated by gelatin zymography. A qPCR and Western blotting were used to examine the mRNA and protein expression levels of MMP-2. Results: The cytokine membrane array of the CM showed a strong signal of MCP-1compared to the control medium, and we thus focused our attention on MCP-1 in the CM. The CM up-regulated the cancer cell proliferation, and the neutralization by anti-MCP-1 antibody inhibited the proliferative effect of the prostate cancer cell lines. The CM greatly increased the invasive activity in the prostate cancer cell lines, and anti-MCP-1 antibody decreased the invasiveness. Gelatin zymography revealed that the CM markedly enhanced the enzymatic activity of MMP-2, and anti-MCP-1 antibody down-regulated its effect. MMP-2 mRNA expression was undetected and the MMP-2 protein level was unchanged between the control medium and CM in DU145 cells. Conclusions: MCP-1 from adipocytes enhances the growth and invasion activity of prostate cancer cells. The inhibition of MCP-1 derived from adipocytes might be an effective treatment for prostate cancer. Citation Format: Yusuke Ito, Hitoshi Ishiguro, Naohito Kobayashi, Hisashi Hasumi, Masatoshi Watanabe, Masahiro Yao, Hiroji Uemura. Adipocyte-derived monocyte chemotactic protein-1 (MCP-1) promotes prostate cancer progression through matrix metalloproteinase (MMP-2) mediated extracellular matrix degradation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 435. doi:10.1158/1538-7445.AM2015-435

Effects of Monocyte Chemotactic Protein-1 and Nuclear Factor of Kappa B Pathway in Rejection of Cardiac Allograft in Rat

BackgroundGraft rejection is a key obstacle to successful heart transplantation. We sought to investigate the expression and role of monocyte chemotactic protein-1 (MCP-1) in rejection of cardiac allografts, as well as the role of the nuclear factor of kappa B (NF-κB) pathway. MethodsHeterotopic cervical heart transplantation was performed using a modified cuff-technique. Recipient rats (n = 12) underwent acute rejection (AR) without any treatment (AR group). The remaining rats (3 groups; n = 12/group) were treated with Cyclosporine A (CsA; CsA group), immunologic tolerance (IT; IT group), and pyrrolidine dithiocarbamate (PDTC; NF-κB inhibitor; PDTC group). We studied the inflammatory infiltration and myocardial fibrosis of cardiac allografts with hematoxylin-eosin (HE) and Masson staining, and detected the expression of MCP-1 by immunohistochemistry and Western blotting. Cardiac allograft vasculopathy (CAV) also was evaluated using van Gieson staining. ResultsThe survival time of the PDTC group (142.37 ± 24.28 days) was significantly longer than that of the AR group (6.54 ± 2.47 days; P = .00073) and the CsA group (93.51 ± 20.17 days; P = .0052). Myocardial fibrosis and CAV in the PDTC group were significantly attenuated compared with the CsA group (P < .01). The expression of MCP-1 in the IT group was markedly lower than in the other 3 groups (P < .05). The expression of MCP-1 in the PDTC group was also significantly lower than the CsA group (1.15 ± 0.27 vs 1.58 ± 0.17; P = .016). ConclusionThese findings suggest that the expression level of MCP-1 could be monitored to reflect the severity of cardiac allograft rejection. PDTC can significantly prevent the rejection of cardiac allografts by inhibiting MCP-1 expression via the suppression of the NF-κB pathway.

Abstract 1429: Role of monocyte chemotactic protein-1 (MCP-1) in the tumor microenvironment.

Abstract Glioblastomas, the most malignant form of gliomas, harbor multiple cell types. In particular, microglial cells can contribute up to 30% of a brain tumor mass, and can promote glioma cell growth and dispersal. The purpose of the present study was to test the hypothesis that glioma cells recruit nearby microglia through an MCP-1-mediated mechanism and enhance their production of MCP-1 in the tumor microenvironment. We evaluated the role of MCP-1 on glioma cell proliferation and invasion. Consistent with previous studies in rat models (Platten et al., 2003), we found that U-87 and A-172 human glioma cells promote microglial migration towards the glioma environment using a modified Boyden chamber migration assay. Furthermore, this effect was decreased after immunoneutralization of MCP-1 released from glioma cells. Additionally, using an antibody array we found that U-87 or A-172 glioma cell conditioned medium stimulates a 7-10 fold increase of MCP-1 release by microglia by 24 hours. We next analyzed the consequences of elevated MCP-1 on the invasiveness and proliferation of glioma cells. Using standard invasion assays with or without microglia in a lower compartment, we demonstrated that microglia significantly increased invasion of glioma cells, but this effect was not blocked by MCP-1 immunoneutralization. This suggests that the stimulatory effect of microglia on glioma invasion was due to some other factor such as release of matrix metalloproteinases (MMPs). In contrast, microglia increased U-87 and A-172 glioma cell proliferation within 72 hours and MCP-1 immunoneutralization reversed this proliferative effect of microglia in both cell lines. Based on these results, we propose that glioma cells release low levels of MCP-1 to recruit nearby microglia and enhance the production of MCP-1. This increased secretion of MCP-1 from microglial cells recruits more microglial cells into the tumor and stimulate glioma progression. A variety of substances released by microglia in tumor microenvironment, including cytokines, growth factors, proteases and extracellular matrix components could lead to increased proliferation and invasiveness of glioma cells. Supported by G11 HD052352, G12 RR03035, 8G12MD007583-27, U54 NS039408 and by the UCC Pilot Project Program Citation Format: Lilia Y. Kucheryavykh, Aixa F. Rivera-Pagán, Kimberleve Rolón-Reyes, Serguey N. Skatchkov, Misty J. Eaton. Role of monocyte chemotactic protein-1 (MCP-1) in the tumor microenvironment. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1429. doi:10.1158/1538-7445.AM2013-1429

Monocyte Chemotactic Protein-1 Promotes Inflammatory Vascular Repair of Murine Carotid Aneurysms via a Macrophage Inflammatory Protein-1α and Macrophage Inflammatory Protein-2–Dependent Pathway

Up to 5% of the population may have a brain aneurysm. If the brain aneurysm ruptures, there is >50% mortality, and more than one third of survivors are dependent. Brain aneurysms detected before rupture can be treated to prevent rupture, or ruptured aneurysms can be treated to prevent rerupture. Endovascular coiling of brain aneurysms is the treatment of choice for some aneurysms; however, up to one quarter of aneurysms may recur. The coiled aneurysms that do not recur are characterized by inflammatory intra-aneurysmal tissue healing; therefore, we studied the biology of this process, specifically the role of monocyte chemotactic protein-1 (MCP-1), a cytokine known for tissue healing. We created coils with a 50:50 poly-dl-lactic glycolic acid (PLGA) coating that released MCP-1 at 3 different doses (100 μg/mL, 1 mg/mL, and 10 mg/mL) and performed a dose-response study for effect on intra-aneurysmal tissue healing in a murine carotid aneurysm model. We then demonstrated that MCP-1 (100 μg/mL)-releasing coils promote significantly greater aneurysm tissue in-growth than bare platinum or PLGA-only coils. We show that MCP-1 recruits the migration of fibroblasts, macrophages, smooth muscle cells, and endothelial cells in vitro in cell migration assays and in vivo in murine carotid aneurysms. Using gfp(+) bone marrow-transplant chimeric mice, we demonstrate that the MCP-1-recruited fibroblasts and macrophages are derived from the bone marrow. We demonstrate that this MCP-1-mediated vascular inflammatory repair occurs via a macrophage inflammatory protein (MIP)-1α- and MIP-2-dependent pathway. MCP-1 released from coiled murine aneurysms causes significant upregulation of MIP-1α and MIP-2 expression by cytokine array assay. Blocking MIP-1α and MIP-2 with antagonist antibody causes a significant decrease in MCP-1-mediated intra-aneurysmal tissue healing. Our findings suggest that MCP-1 has a critical role in promoting inflammatory intra-aneurysmal tissue healing in an MIP-1α- and MIP-2-dependent pathway.

Osteoclast precursor differentiation by MCPIP via oxidative stress, endoplasmic reticulum stress, and autophagy

Osteoclasts (OCs) are responsible for bone resorption in inflammatory joint diseases. Monocyte chemotactic protein-1 (MCP-1) has been shown to induce differentiation of monocytes to OC precursors, but nothing is known about the underlying mechanisms. Here, we elucidate how MCPIP, induced by MCP-1, mediates this differentiation. Knockdown of MCPIP abolished MCP-1-mediated expression of OC markers, tartrate-resistant acid phosphatase, and serine protease cathepsin K. Expression of MCPIP induced p47(PHOX) and its membrane translocation, reactive oxygen species formation, and induction of endoplasmic reticulum (ER) stress chaperones, up-regulation of autophagy marker, Beclin-1, and lipidation of LC3, and induction of OC markers. Inhibition of oxidative stress attenuated ER stress and autophagy, and suppressed expression of OC markers. Inhibition of ER stress by a specific inhibitor or by knockdown of IRE1 blocked autophagy and induction of OC markers. ER stress inducers, tunicamycin and thapsigargin, induced expression of OC markers. Autophagy inhibition by 3'-methyladenine, LY294002, wortmannin or by knockdown of Beclin-1 or Atg 7 inhibited MCPIP-induced expression of OC markers. These results strongly suggest that MCP-1-induced differentiation of OC precursor cells is mediated via MCPIP-induced oxidative stress that causes ER stress leading to autophagy, revealing a novel mechanistic insight into the role of MCP-1 in OCs differentiation.

P24 Cytokine biomarker profiling in acetaminophen-induced acute liver failure: importance of monocyte chemotactic protein-1 in prognosis and hepatic encephalopathy

IntroductionInflammatory cytokines have recently been described as reflecting severity of liver injury, grade of encephalopathy and prognosis in acute liver failure (ALF). The role of monocyte chemotactic protein-1 and peripheral...

MCP-1 (Monocyte Chemotactic Protein-1)-induced Protein, a Recently Identified Zinc Finger Protein, Induces Adipogenesis in 3T3-L1 Pre-adipocytes without Peroxisome Proliferator-activated Receptor γ

Adipogenesis is a key differentiation process relevant to obesity and associated diseases such as type 2 diabetes. This process involves temporally regulated genes controlled by a set of transcription factors, CCAAT/enhancer-binding proteins (C/EBP) beta, C/EBPdelta, and C/EBPalpha and peroxisome proliferator-activated receptor gamma (PPARgamma). Currently, PPARgamma is universally accepted as the master regulator that is necessary and sufficient to induce adipogenesis as no known factor can induce adipogenesis without PPARgamma. We present evidence that a novel zinc finger protein, MCP-1-induced protein (MCPIP), can induce adipogenesis without PPARgamma. Classical adipogenesis-inducing medium induces MCP-1 production and expression of MCPIP in 3T3-L1 cells before the induction of the C/EBP family of transcription factors and PPARgamma. Knockdown of MCPIP prevents their expression and adipogenesis as measured by expression of adipocyte markers and lipid droplet accumulation. Treatment of 3T3-L1 cells with MCP-1 or forced expression of MCPIP induces expression of C/EBPbeta, C/EBPdelta, C/EBPalpha, and PPARgamma and adipogenesis without any other inducer. Forced expression of MCPIP induces expression of the C/EBP family of transcription factors and adipogenesis in PPARgamma(-/-) mouse embryonic fibroblasts. Thus, MCPIP is a newly identified protein that can induce adipogenesis without PPARgamma.

Etanercept reduces the serum levels of macrophage chemotactic protein-1 in patients with rheumatoid arthritis

This study was performed to analyze the effect of etanercept, the soluble tumor necrosis factor-α (TNF-α) receptor, on the serum levels of several chemokines including monocyte chemotactic protein-1 (MCP-1), regulated upon activation normal T expressed and presumably secreted (RANTES), and granzyme B in rheumatoid arthritis (RA) patients. Twenty-eight patients with RA were administered etanercept once or twice a week for more than 6 months. Clinical and laboratory parameters were measured and serum levels of MCP-1, RANTES, and granzyme B were determined using enzyme-linked immunosorbent assay (ELISA) kits at baseline and at 3 and 6 months after the initial treatment. In addition, the levels of MCP-1, RANTES, and granzyme B produced by cultured synovial cells stimulated with TNF-α were measured. A significant decrease in serum MCP-1 levels was observed at 3 and 6 months after initial treatment with etanercept. Serum RANTES and granzyme B levels did not show significant changes. TNF-α induced MCP-1, RANTES, and granzyme B production in cultured synovial cells from RA patients. Serum MCP-1 levels were significantly correlated with the disease activity scores of 28 joints combined with CRP (DAS28-CRP), indicating the role of MCP-1 in the pathogenesis of rheumatoid inflammation. This study demonstrated that a reduction of MCP-1 production in RA patients was a newly determined effect of etanercept. Another cascade not associated with TNF-α may induce granzyme B and RANTES production in RA patients.

Role of MCP-1 in cardiovascular disease: molecular mechanisms and clinical implications

Many of the major diseases, including cardiovascular disease, are widely recognized as inflammatory diseases. MCP-1 (monocyte chemotactic protein-1) plays a critical role in the development of cardiovascular diseases. MCP-1, by its chemotactic activity, causes diapedesis of monocytes from the lumen to the subendothelial space where they become foam cells, initiating fatty streak formation that leads to atherosclerotic plaque formation. Inflammatory macrophages probably play a role in plaque rupture and the resulting ischaemic episode as well as restenosis after angioplasty. There is strong evidence that MCP-1 plays a major role in myocarditis, ischaemia/reperfusion injury in the heart and in transplant rejection. MCP-1 also plays a role in cardiac repair and manifests protective effects under certain conditions. Such protective effects may be due to the induction of protective ER (endoplasmic reticulum) stress chaperones by MCP-1. Under sustained ER stress caused by chronic exposure to MCP-1, the protection would break down resulting in the development of heart failure. MCP-1 is also involved in ischaemic angiogenesis. The recent advances in our understanding of the molecular mechanisms that might be involved in the roles that MCP-1 plays in cardiovascular disease are reviewed. The gene expression changes induced by the signalling events triggered by MCP-1 binding to its receptor include the induction of a novel zinc-finger protein called MCPIP (MCP-1-induced protein), which plays critical roles in the development of the pathophysiology caused by MCP-1 production. The role of the MCP-1/CCR2 (CC chemokine receptor 2) system in diabetes, which is a major risk factor for cardiovascular diseases, is also reviewed briefly. MCP-1/CCR2- and/or MCPIP-targeted therapeutic approaches to intervene in inflammatory diseases, including cardiovascular diseases, may be feasible.

Etanercept reduces the serum levels of macrophage chemotactic protein-1 in patients with rheumatoid arthritis

This study was performed to analyze the effect of etanercept, the soluble tumor necrosis factor-alpha (TNF-alpha) receptor, on the serum levels of several chemokines including monocyte chemotactic protein-1 (MCP-1), regulated upon activation normal T expressed and presumably secreted (RANTES), and granzyme B in rheumatoid arthritis (RA) patients. Twenty-eight patients with RA were administered etanercept once or twice a week for more than 6 months. Clinical and laboratory parameters were measured and serum levels of MCP-1, RANTES, and granzyme B were determined using enzyme-linked immunosorbent assay (ELISA) kits at baseline and at 3 and 6 months after the initial treatment. In addition, the levels of MCP-1, RANTES, and granzyme B produced by cultured synovial cells stimulated with TNF-alpha were measured. A significant decrease in serum MCP-1 levels was observed at 3 and 6 months after initial treatment with etanercept. Serum RANTES and granzyme B levels did not show significant changes. TNF-alpha induced MCP-1, RANTES, and granzyme B production in cultured synovial cells from RA patients. Serum MCP-1 levels were significantly correlated with the disease activity scores of 28 joints combined with CRP (DAS28-CRP), indicating the role of MCP-1 in the pathogenesis of rheumatoid inflammation. This study demonstrated that a reduction of MCP-1 production in RA patients was a newly determined effect of etanercept. Another cascade not associated with TNF-alpha may induce granzyme B and RANTES production in RA patients.

Sequential Evaluation of Serum Monocyte Chemotactic Protein 1 Among Asymptomatic State and Acute Exacerbation and Remission of Asthma in Children

Background. Monocyte chemotactic protein 1 (MCP-1) plays an important role in various immune and allergic disorders since it is a potent chemo-attractant for inflammatory cells, such as eosinophils, memory T cells, and monocytes. Objective. To investigate serum MCP-1 during asymptomatic state and acute attacks of bronchial asthma. Methods. In this longitudinal cohort design study, sequential serum levels of MCP-1 were measured by a sandwich enzyme-linked immunosorbent assay (ELISA). Twenty-four asthma patients' MCP-1 levels were examined at 5 time points: during the asymptomatic phase, in an acute wheezing episode, and at 1 week, 1 month, and 2 months after acute asthma attack. Fifteen children without asthma were enrolled as control. Results. During the asymptomatic phase of asthma, serum MCP-1 levels were significantly higher than that of normal controls (329.57 ± 99.20 pg/ml vs. 213.63 ± 77.29 pg/ml, p = 0.001). In comparison with the asymptomatic phase, the serum MCP-1 levels during the acute asthma attack were significantly higher (682.88 ± 88.45 pg/ml vs. 329.57 ± 99.20 pg/ml, p < 0.001). After treatment of acute asthma exacerbation, all of the serum MCP-1 levels declined within 1 week, but were still higher than control 2 months later. Conclusion. In asthma patients, the consistently elevated serum levels of MCP-1 suggest its role in the pathogenesis of bronchial asthma - not only in the chronic inflammatory processes, but also in acute asthma attack exacerbation. These findings suggest a possible role for MCP-1 in the pathogenesis of asthma and a potential role for its use in anti-asthma treatment in the future.

Activation of MCP-1/CCR2 axis promotes prostate cancer growth in bone

Prostate cancer (PCa) frequently metastasizes to bone resulting in a mixture of osteolytic and osteoblastic lesions. We have previously reported that monocyte chemotactic protein-1 (MCP-1) is chemotactic for PCa cells, and its receptor, CCR2 expression, correlates with pathological stages. However, the role of MCP-1/CCR2 axis on PCa progression in bone remains unclear. We first evaluated the serum levels of MCP-1 in patients with bone metastases or localized PCa by enzyme-linked immunosorbent assay. We found that MCP-1 levels were elevated in patients with bone metastases compared to localized PCa. We further determined the effects of knockdown CCR2 or MCP-1 on PCa cell invasion and the tumor cell-induced osteoclast activity in vitro, respectively. PCa C4-2B and PC3 cells were transfected stably with either CCR2 short hairpin RNA (shRNA) or a scrambled RNA. CCR2 knockdown significantly diminished the MCP-1-induced PCa cell invasion. In addition, the MCP-1 production was knocked down by MCP-1 shRNA in C4-2B and PC3 cells. Conditioned media (CM) was collected and determined for the CM-induced osteoclast formation in vitro. MCP-1 knockdown significantly decreased the PCa CM-induced osteoclast formation. Finally, MCP-1 knockdown PC3 cells were implanted into the tibia of SCID mice for 4 weeks. Tumor volume was determined by histopathology and bone histomorphometry. MCP-1 knockdown diminished PC3 tumor growth in bone. We concluded that activation of MCP-1/CCR2 axis promotes PCa growth in bone. This study suggests that MCP-1 may be a target for PCa progression.

Abstract 396: Role of Monocyte Chemotactic Protein-1 in Obesity Involves a Newly Discovered Transcription Factor MCPIP

Monocyte chemotactic protein-1 (MCP) that is well known to play a major role in the development of cardiovascular diseases, was recently reported to be involved also in obesity. We recently discovered that MCP-1 treatment of human monocytes induces a novel CCCH zinc finger transcription factor designated MCP-induced protein (MCPIP). In the present study we report that in the white adipose tissue of high fat diet fed mice, MCPIP was induced when body mass and fasting glucose level were elevated, beginning at about 8 weeks on the diet. Six MCPIP-induced novel genes, with no previously known function, ltv , lzp , creld2 , ufm1 , cdh12 and cdh19, were induced in the white adipose tissue, starting at three months of high fat feeding; the increases in fasting glucose level, MCPIP transcript level and the transcript levels of the novel genes showed further progressive increases during the 5 months on the high fat diet. Similar molecular events were also observed during differentiation of NIH 3T3 -L1 cells into adipocytes in culture in the presence of dexamethasone and insulin. Under these conditions MCP-1 production was induced reaching a peak level at 24hr. MCPIP transcript level showed marked increase within 1 hr and reached a maximum at 2 days. ufm1 , lzp , and creld2 reached maximal levels at 4 hr, whereas ltv reached maximal level in 1–2 days, and cdh12 and cdh19 reached maximal levels in one day. Involvement of MCPIP in the differentiation process was indicated by the finding that transfection of 3T3 cells with MCPIP expression plasmid caused differentiation of these cells into adipocytes under non-inducing conditions in the absence of dexamethasone and insulin. This differentiation was accompanied by induction of the six novel MCPIP-induced genes. Knockdown of MCPIP with specific siRNA suppressed differentiation of 3T3 cells into adipocytes and induction of the six MCPIP-induced genes. These results indicate a role for MCP-1 in adipogenesis and that this role is mediated via the newly discovered transcription factor MCPIP.

Monocyte Chemotactic Protein-1 Secreted by Primary Breast Tumors Stimulates Migration of Mesenchymal Stem Cells

Major barriers to effective adenovirus-based gene therapy include induction of an immune response and tumor-specific targeting of vectors. The use of mesenchymal stem cells (MSC) as systemic delivery vehicles for therapeutic genes has been proposed as a result of their combined ability to home in on the tumor site and evade the host immune response. This study is aimed at investigating factors mediating homing of human MSCs to breast cancer primary cultures and cell lines in vitro and in vivo. Fluorescently labeled MSCs were given to mice bearing breast cancer xenografts, and tumor tissue was harvested to detect MSC engraftment. MSC migration in response to primary breast tumors in vitro was quantified, and chemokines secreted by tumor cells were identified. The role of monocyte chemotactic protein-1 (MCP-1) in cell migration was investigated using antibodies and standards of the chemokine. Serum MCP-1 was measured in 125 breast cancer patients and 86 healthy controls. Engrafted MSCs were detected in metastatic breast tumors in mice after systemic administration. There was a significant increase in MSC migration in response to primary breast tumor cells in vitro (6-fold to 11-fold increase). Tumor explants secreted a variety of chemokines including GROalpha, MCP-1, and stromal cell-derived factor-1alpha. An MCP-1 antibody caused a significant decrease (37-42%) in MSC migration to tumors. Serum MCP-1 levels were significantly higher in postmenopausal breast cancer patients than age-matched controls (P < 0.05). These results highlight a role for tumor-secreted MCP-1 in stimulating MSC migration and support the potential of these cells as tumor-targeted delivery vehicles for therapeutic agents.

Monocyte chemotactic protein-1 and its role in insulin resistance

In obesity, there is a strong link between increased adipose tissue mass and development of insulin resistance in tissues such as liver and muscle. Under these conditions, adipose tissue synthesizes various pro-inflammatory chemokines such as monocyte chemotactic protein-1. This review provides a summary of recent knowledge on the role of monocyte chemotactic protein-1 in adipose tissue inflammation and insulin resistance. Monocyte chemotactic protein-1 is a proinflammatory adipokine that is believed to play a role in the pathogenesis of obesity and diabetes. New in-vitro data demonstrate that monocyte chemotactic protein-1 has the ability to induce insulin resistance in adipocytes and skeletal muscle cells. By using mice that either overexpress monocyte chemotactic protein-1 or are deficient in monocyte chemotactic protein-1 or its receptor, exciting new insights have been obtained into the role of monocyte chemotactic protein-1 in adipose tissue inflammation and insulin resistance. Monocyte chemotactic protein-1 is an adipokine with insulin-resistance-inducing capacity that is related to increased adipose tissue mass in obesity and insulin resistance. It plays an important role in adipose tissue inflammation by recruiting macrophages into fat. Monocyte chemotactic protein-1 is thus a therapeutic target, and may represent an important factor linking adipose tissue inflammation, obesity and type 2 diabetes.

Role of monocyte chemotactic protein-1 and nuclear factor kappa B in the pathogenesis of proliferative diabetic retinopathy

Intraocular concentrations of monocyte chemotactic protein-1 (MCP-1) are increased in proliferative diabetic retinopathy (PDR). Nuclear factor kappa B (NF-κB) is a transcription factor, and NF-κB binding site is located in gene promoter of MCP-1. This study was conducted to investigate the potential role of MCP-1 and NF-κB in the pathogenesis of PDR. Epiretinal membrane (ERM) samples were obtained during vitrectomy from 19 eyes with PDR and 16 eyes with idiopathic ERM. They were processed for RT–PCR analysis. Four PDR ERMs were processed for immunohistochemical analysis. In addition, cultured Müller glial cells were stimulated with glycated albumin or high glucose. After the stimulation, we examined nuclear localization of NF-κB p50, MCP-1 promoter activity, and MCP-1 concentration in culture media. MCP-1 mRNA expression was significantly higher in PDR (74%) than in idiopathic ERMs (38%) ( P < 0.05). Immunohistochemical analysis revealed that MCP-1 protein is colocalized with active form of NF-κB p50. In vitro studies demonstrated that glycated albumin or high glucose induces NF-κB activation followed by up-regulation of MCP-1 promoter activity and protein production in glial cells. These results suggest that MCP-1, under the regulation of NF-κB, is involved in the pathogenesis of PDR.

Paracrine Regulation of Vascular Endothelial Growth Factor-A Expression During Macrophage-Melanoma Cell Interaction: Role of Monocyte Chemotactic Protein-1 and Macrophage Colony-Stimulating Factor

Tumor-associated macrophages are major infiltrates of human solid malignancies and play an important role in tumor angiogenesis by production of angiogenic factors. In the present study, we examined whether macrophage- melanoma cell interaction regulates vascular endothelial cell growth factor-A (VEGF-A) expression in macrophages. We analyzed the expression of mediators of monocyte recruitment and differentiation, such as monocyte chemotactic protein-1 (MCP-1) and macrophage colony-stimulating factor (M-CSF) in malignant melanoma specimens and tumor cells with different metastatic potential. Our data demonstrate that MCP-1 and M-CSF are differentially expressed in human malignant melanomas from different thickness and depth of invasion and cell lines. Next, we examined the effect of MCP-1 and M-CSF on modulation of VEGFA expression in monocytes/macrophages. Treatment of human monocytes with M-CSF and MCP-1 enhanced VEGF-A expression by increased hypoxia-inducible factor-1alpha (HIF-1alpha) expression and enhanced activation of the hypoxia response element (HRE). Further activation of monocytes and monocyte-derived macrophages (MDM) by lipopolysaccharide (LPS) caused an increase in VEGF-A expression. We demonstrate that coculture of melanoma cells with monocytes enhanced VEGF-A secretion, and conditioned medium from MDMs enhanced melanoma cell expression of VEGF-A. Furthermore, conditioned medium from melanoma cells enhanced VEGF-A expression in human monocytes, which was abrogated by anti-M-CSF neutralizing antibody. In summary, we demonstrate that MCP-1 and M-CSF, critical for monocyte recruitment, activation, and differentiation, differentially regulate VEGF-A expression and may play an important role in monocyte/macrophage- mediated tumor angiogenesis.

Tumour-associated macrophage infiltration, neovascularization and aggressiveness in malignant melanoma: role of monocyte chemotactic protein-1 and vascular endothelial growth factor-A

The objective of this study was to evaluate the role of tumour-associated macrophages (TAMs) in malignant melanoma progression, invasion and angiogenesis. We examined the levels of macrophage infiltration and monocyte chemotactic protein-1 (MCP-1), neovascularization and vascular endothelial growth factor-A (VEGF-A) in different Clark's level melanomas with varying thicknesses and metastases. The level of TAM density was significantly higher in thick (>0.75 mm) than thin (<or=0.75 mm) melanomas, and positively correlated with melanoma invasiveness and metastasis. In contrast, MCP-1 expression was significantly lower in thick (>0.75 mm) than thin (<or=0.75 mm) melanomas and negatively correlated with melanoma aggressiveness and invasion. We did not observe any significant difference in the levels of neovascularization between thin and thick melanomas, and no correlation with VEGF-A expression, TAM density or melanoma aggressiveness and invasion. Interestingly, levels of VEGF-A were significantly higher in metastatic melanoma than in thick melanoma. In addition, we observed lower levels of MCP-1 messenger RNA (mRNA) expression in more aggressive melanomas and in cell lines with higher metastatic potential. In summary, our data suggest a distinct pattern of TAM infiltration, MCP-1 expression, neovascularization and VEGF-A expression during human melanoma progression, and a complex interaction between TAMs and melanoma cells in the regulation of melanoma progression, angiogenesis and metastasis.

Alterations in expression of monocyte chemotactic protein-1 in the simian immunodeficiency virus model of disseminated Mycobacterium avium complex.

Mycobacterium avium complex (MAC) infection is the most common disseminated bacterial infection in untreated patients with acquired immunodeficiency syndrome (AIDS). We investigated the potential role of monocyte chemotactic protein-1 (MCP-1) in the pathogenesis of disseminated MAC, using the simian immunodeficiency virus (SIV)/macaque model of AIDS. Macaques were inoculated with SIV, followed by challenge with a pathogenic AIDS isolate of M. avium 14 days later. After challenge with M. avium, marked increases in serum MCP-1 levels were detected in SIV-infected macaques, a finding that was duplicated in coinoculated bronchoalveolar macrophages. MCP-1 levels were significantly higher in SIV-infected macaques than in non-SIV-infected controls (327.1 vs. 151.5 pg/mL, respectively; P=.04), suggesting that up-regulation of MCP-1 contributes to the development of progressive mycobacterial disease. Similarly, morphometric analysis revealed increased expression of MCP-1 in hepatic microgranulomas from SIV-infected macaques. We conclude that the pronounced increases in MCP-1 levels demonstrated in tissue and serum samples after M. avium inoculation may play a role in the development of disseminated mycobacterial disease.