低氧诱导因子1α通过CX3CR1在胰腺癌嗜神经侵袭中作用

  目的   探索低氧诱导因子1α(HIF-1α)和细胞趋化因子受体CX3CR1的相互调节在胰腺癌嗜神经侵袭方面的作用。   方法   通过免疫组织化学实验, 探究在胰腺癌的组织样本中HIF-1α与CX3CR1的相互作用对嗜神经侵袭的作用; 用siRNA双链和过表达质粒沉默/过表达HIF-1α和CX3CR1基因, 然后通过Western blot免疫印迹实验检测HIF-1α、CX3CR1表达的变化。   结果   在胰腺癌组织中, HIF-1α蛋白表达水平与肿瘤直径(F=7.81, P < 0.05), 淋巴结转移(r=0.24, P < 0.01), 肿瘤的病理淋巴结转移阶段(r=0.39, P < 0.05)相关; 在人类胰腺癌细胞系、胰腺癌患者手术标本中, HIF-1α和CX3CR1的表达均具有相关性, 并且与胰腺癌的嗜神经侵袭相关联。   结论   HIF-1α和CX3CR1的相互作用可以调节胰腺癌的嗜神经侵袭。      

Early expression of the fractalkine receptor CX3CR1 in pancreatic carcinogenesis

Background:

In pancreatic ductal adenocarcinoma (PDAC), fractalkine receptor CX3CR1 contributes to perineural invasion (PNI). We investigated whether CX3CR1 expression occurs early in PDAC and correlates with tumour features other than PNI.

Methods:

We studied CX3CR1 and CX3CL1 expression by immunohistochemistry in 104 human PDAC and coexisting Pancreatic Intraepithelial Neoplasia (PanIN), and in PdxCre/LSL-Kras^G12D mouse model of PDAC. CX3CR1 expression in vitro was studied by a spheroid model, and in vivo by syngenic mouse graft of tumour cells.

Results:

In total, 56 (53.9%) PDAC expressed CX3CR1, 70 (67.3%) CX3CL1, and 45 (43.3%) both. CX3CR1 expression was independently associated with tumour glandular differentiation (P=0.005) and PNI (P=0.01). Pancreatic Intraepithelial Neoplasias were more frequently CX3CR1+ (80.3%, P<0.001) and CX3CL1+ (86.8%, P=0.002) than matched cancers. The survival of PDAC patients was better in those with CX3CR1+ tumour (P=0.05). Mouse PanINs were also CX3CR1⁺ and -CL1⁺. In vitro, cytokines significantly increased CX3CL1 but not CX3CR1 expression. Differently, CX3CR1 was upregulated in tumour spheroids, and in vivo only in well-differentiated tumours.

Conclusion:

Tumour differentiation, rather than inflammatory signalling, modulates CX3CR1 expression in PanINs and PDAC. CX3CR1 expression pattern suggests its early involvement in PDAC progression, outlining a potential target for interfering with the PanIN transition to invasive cancer.     

CX3CR1/CX3CL1 axis negatively controls glioma cell invasion and is modulated by transforming growth factor-beta1

The chemokine CX3CL1 is constitutively expressed in the central nervous system by neurons and astrocytes controlling neuronal survival and neurotransmission. In this work, we analyzed the expression and function of the chemokine CX3CL1 and its receptor, CX3CR1, by human glioma cells. We show that both molecules are expressed on the tumor cell plasma membrane and that soluble CX3CL1 accumulates in the culture supernatants, indicating that the chemokine is constitutively released. We found that CX3CR1 is functional, as all the cell lines adhered to immobilized recombinant CX3CL1 and migrated in response to the soluble form of this chemokine. In addition, the blockade of endogenous CX3CL1 function by means of a neutralizing monoclonal antibody markedly delayed tumor cell aggregation and increased their invasiveness. We also show that CX3CL1 expression is potently modulated by the transforming growth factor-beta1 (TGF-beta1), a key regulator of glioma cell invasiveness. Indeed, both the treatment of glioma cells with recombinant TGF-beta1 and the inhibition of its endogenous expression by siRNA showed that TGF-beta1 decreases CX3CL1 mRNA and protein expression. Overall, our results indicate that endogenously expressed CX3CL1 negatively regulates glioma invasion likely by promoting tumor cell aggregation, and that TGF-beta1 inhibition of CX3CL1 expression might contribute to glioma cell invasive properties.     

The involvement of the fractalkine receptor in the transmigration of neuroblastoma cells through bone-marrow endothelial cells

Transendothelial migration (TEM) of tumor cells is a crucial step in metastasis formation. The prevailing paradigm is that the mechanism underlying TEM of tumor cells is similar to that of leukocytes involving adhesion molecules and chemokines. Fractalkine (CX3CL1) is a unique membrane-bound chemokine that functions also as an adhesion molecule. CX3CL1 can be cleaved to a soluble fragment, capable of attracting fractalkine receptor (CX3CR1)-expressing cells. In the present study, we asked if CX3CR1 is involved in the TEM of neuroblastoma cells. We demonstrated that biologically functional CX3CR1 is expressed by several neuroblastoma cell lines. Most importantly, CX3CR1-expressing neuroblastoma cells were stimulated by CX3CL1 to transmigrate through human bone-marrow endothelial cells. A dose dependent phosphorylation of ERK1/2 and AKT was induced in CX3CR1-expressing neuroblastoma cells by soluble CX3CL1. In addition to CX3CR1, neuroblastoma cells also express the CX3CL1 ligand. Membrane CX3CL1 expression was downregulated and the shedding of soluble CX3CL1 was upregulated by PKC activation. Taken together, the results of this study indicate that CX3CR1 plays a functional role in transmigration of neuroblastoma cells through bone-marrow endothelium. These results led us to hypothesize that the CX3CR1-CX3CL1 axis takes part in bone-marrow metastasis of neuroblastoma.     

Defective antitumor responses in CX3CR1-deficient mice

Innate immunity is critically important for tumor surveillance and regulating tumor metastasis. Fractalkine (FKN, CX3CL1), operating through the receptor CX3CR1, is an effective chemoattractant and adhesion receptor for NK cells and monocytes, important constituents of the innate immune response. Previous studies have shown that over-expression of CX3CL1 by tumor cells enhances antitumor responses. However, since most tumors do not express CX3CL1, it remains unclear if CX3CL1/CX3CR1 has a role in tumor immunity in the absence of ligand over-expression. To determine the role of CX3CL1 and CX3CR1 in regulating antitumor immune responses, we tested the response of wildtype and CX3CR1-deficient animals to unmanipulated B16 melanoma that does not express CX3CL1. We studied the distribution and trafficking of mononuclear cells (MNC) under homeostatic conditions and in the presence of B16 metastatic melanoma, cytotoxic activity, and cytokine production in wild-type and CX3CR1-deficient animals. We found that B16-treated CX3CR1-/- mice had increased lung tumor burden and cachexia. There was a selective reduction of monocytes and NK cells in the lungs of CX3CR1-deficient animals under homeostatic conditions and in response to B16. CX3CR1-deficient NK cells effectively killed B16 cells in cytotoxicity assays. However, CX3CR1-deficient NK cells exhibited a tumorigenic cytokine production profile with defective IFN-gamma expression and enhanced IL-6 production in response to TLR3 activation with polyIC. Our studies indicate that CX3CR1 is an important contributor to innate immunity at multiple levels. Its role in tumor immunity is not limited by expression of CX3CL1 by tumor cells.     

Human glioblastoma tumours and neural cancer stem cells express the chemokine CX3CL1 and its receptor CX3CR1

Human gliomas represent an unmet clinical challenge as nearly two-thirds of them are highly malignant lesions with fast progression, resistance to treatment and poor prognosis. The most severe form, the glioblastoma multiforme, is characterised by a marked and diffuse infiltration through the normal brain parenchyma. Given the multiple effects of chemokines on tumour progression, aim of this study was to analyse the expression of the chemokine CX3CL1 and of its specific receptor CX3CR1 in 36 human surgical glioma samples, with different degrees of histological malignancy and in glioblastoma-derived neurospheres. Herein we show that both ligand and receptor are expressed at the mRNA and protein levels in most specimens (31/36). While receptor expression was similarly detected in low or high grade tumours, the uppermost scores of CX3CL1 were found in grades III–IV tumours: oligodendrogliomas, anaplastic astrocytomas and glioblastomas. Accordingly, the expression of CX3CL1 was inversely correlated with patient overall survival (p = 0.01). Glioblastoma-derived neurospheres, containing a mixed population of stem and progenitor cells, were positive for both CX3CR1 and for the membrane-bound chemokine, which was further up-regulated and secreted after TNF-IFNγ stimulation. Confocal microscopy of 3D neurospheres showed that the ligand was primarily expressed in the outer layer cells, with points of co-localisation with CX3CR1, indicating that this ligand–receptor pair may have important intercellular adhesive functions. The high expression of CXC3L1 in the most severe forms of gliomas suggests the involvement of this chemokine and its receptor in the malignant behaviour of these tumours.     

Fractalkine mediates natural killer-dependent antitumor responses in vivo

CX3CR1 has been described previously as a marker of human cytotoxic effector cells. We evaluated the possibility of using its ligand, CX3CL1, to redirect immune response against tumors. When murine lymphoma cell lines (EL4 and its derivative EG7) stably transfected with human-CX3CL1 were injected s.c. into C57BL/6 mice, the tumor growth was severely impaired when compared with the growth of control cell lines. This antitumor effect of CX3CL1 was also found in T- and B-cell-deficient Rag1-/- mice but vanished in natural killer (NK) cell-deficient beige mice and in CX3CR1-/- mice, suggesting the involvement of CX3CR1-expressing NK cells. In addition, increased NK cell infiltration was observed in CX3CL1-producing tumors compared with controls. The effect of CX3CR1 on tumor growth required host cytotoxic effector cell functions because both IFNgamma-/- and perforin-/- mice were resistant to CX3CL1 antitumor effect. Finally, intratumoral injection of DNA plasmid coding for a chimeric immunoglobulin presenting the CX3CL1 chemokine domain provided strong antitumor activity. Together, these data demonstrate that the CX3CL1 can reduce incidence and size of lymphoma in vivo through increased recruitment of activated NK cytotoxic cells. These findings offer the first evidence of the potential of chimeric immunoglobulin-chemokines in anticancer therapy.     

Involvement of interaction between Fractalkine and CX3CR1 in cytotoxicity of natural killer cells against tumor cells

Many chemokine receptors are typically found on natural killer cells, including CX3CR1, the receptor for the chemokine fractalkine (FKN). This study explored whether interaction between CX3CR1 and FKN is relevant for NK cell functions in cytotoxicity against tumors. FKN expression was examined by polymerase chain reaction and CX3CR1 expression in NK cells was analyzed by flow cytometry. NK cell cytotoxicity was examined by 4-h 51Cr-release assay. FKN was expressed in a variety of tumor cell lines such as K562 cells, an NK-sensitive cell line. Approximately 90% of peripheral blood NK cells and almost all of the NK cell line, NK-92 cells, expressed CX3CR1. Anti-CX3CR1 antibody strongly neutralized the cytotoxicity of NK cells against K562 cells, and pretreatment of NK cells with recombinant soluble FKN improved the cytolytic function on tumor cells. This study demonstrates that an interaction between CX3CR1 on NK cells and FKN on tumor cells is involved in the natural cytotoxicity of NK cells against tumors.     

趋化因子CX3CL1／CX3CR1生物轴促进铂类药物诱导卵巢癌细胞凋亡的研究

目的 探讨趋化因子CX3CL1及其受体CX3CR1与卵巢癌患者耐药及预后的关系,以及裸鼠耐药模型中CX3CL1、CX3CR1在铂类耐药过程中的变化,分析其表达水平与Fas信号通路的相关性。方法 利用癌症基因图集（TCGA）数据库中卵巢癌患者的全基因组表达谱,分析CX3CL1和CX3CR1在铂类敏感和耐药患者中的表达与临床病理特征的关系。利用已构建的带有绿色荧光标记的卵巢癌SKOV3敏感细胞（SKOV3-GFP）和顺铂耐药细胞（SKOV3-GFP／DDPⅢ）进行裸鼠皮下种植,成瘤后分次给予顺铂体内注射;qRT-PCR检测第0、2、5、8次顺铂注射后移植瘤组织中CX3CL1、CX3CR1与Fas信号通路上基因的表达水平。结果 CX3CL1表达与卵巢癌FIGO分期和铂类耐药产生呈负相关（r=-0.112,P=0.030;r=-0.106,P=0.044）;CX3CR1表达与无进展生存时间呈负相关（r=-0.130,P=0.029）和1年复发率呈正相关（r=0.119,P=0.045）。铂类敏感组卵巢癌患者的卵巢组织中CX3CL1的平均表达量为3.96±0.039,显著高于耐药组的3.64±0.55（P=0.000）。顺铂干预后,裸鼠皮下移植瘤体质量随时间推移而增加,SKOV3-GFP／DDPⅢ组形成的移植瘤体质量始终高于SKOV3-GFP组,在第5次给药后移植瘤开始逐渐变小。顺铂干预后,SKOV3-GFP组CX3CL1、CX3CR1表达水平明显升高（P=0.001,P=0.002）,SKOV3-GFP／DDPⅢ组CX3CL1、CX3CR1基因表达始终处于较低水平。SKOV3-GFP／DDPⅢ组中Fas信号通路上的Fas、FADD的表达较SKOV3-GFP组明显降低（P＜0.001）;而PARP1基因的相对表达较SKOV3 GFP组明显上调（P＜0.001）。CX3CL1和CX3CR1的表达与Fas信传导通路上节点基因Fas、FADD表达呈正相关,与下游PARP1基因的表达呈负相关。结论 CX3CL1、CX3CR1表达下调与铂类耐药形成相关,两者可能具有维持肿瘤细胞对铂类药物敏感性的作用。CX3CL1、CX3CR1在耐药细胞中的低表达可能通过某种机制抑制Fas信号传导通路,使其传导失调,抑制细胞凋亡及诱发卵巢癌对铂类耐药。     

B cell lymphomas express CX3CR1 a non-B cell lineage adhesion molecule

To study the differential expression of cell membrane-bound receptors and their potential role in growth and/or survival of the tumor cells, highly purified follicular lymphoma cells were analyzed, using gene expression analysis, and compared to non-malignant B cell populations. Filtering the genome for overexpressed genes coding for cell membrane-bound proteins/receptors resulted in a hit list of 27 identified genes. Among these, we have focused on the aberrant over expression of CX3CR1, in different types of B cell lymphoma, as compared to non-malignant B cells. We show that CX3CR1, which normally is not expressed on B cells, is expressed both at the mRNA and protein level in several subtypes of lymphoma. CX3CR1 has also shown to be involved in the homing to specific tissues that express the ligand, CX3CL1, in breast and prostate cancer and may thus be involved in dissemination of lymphoma.     

Stromal-derived factor-1α/CXCL12-CXCR4 chemotactic pathway promotes perineural invasion in pancreatic cancer

Perineural invasion (PNI) is considered as an alternative route for the metastatic spread of pancreatic cancer cells; however, the molecular changes leading to PNI are still poorly understood. In this study, we show that the CXCL12/CXCR4 axis plays a pivotal role in the neurotropism of pancreatic cancer cells to local peripheral nerves. Immunohistochemical staining results revealed that CXCR4 elevation correlated with PNI in 78 pancreatic cancer samples. Both in vitro and in vivo PNI models were applied to investigate the function of the CXCL12/CXCR4 signaling in PNI progression and pathogenesis. The results showed that the activation of the CXCL12/CXCR4 axis significantly increased pancreatic cancer cells invasion and promoted the outgrowth of the dorsal root ganglia. CXCL12 derived from the peripheral nerves stimulated the invasion and chemotactic migration of CXCR4-positive cancer cells in a paracrine manner, eventually leading to PNI. In vivo analyses revealed that the abrogation of the activated signaling inhibited tumor growth and invasion of the sciatic nerve toward the spinal cord. These data indicate that the CXCL12/CXCR4 axis may be a novel therapeutic target to prevent the perineural dissemination of pancreatic cancer.     

Perineural Invasion in Pancreatic Cancer: Advanced Research in the Neuro-cancer Interactions

Pancreatic Cancer (PCa) is characterized by prominently local nerve alterations and perineural invasion (PNI), which frequently affects the extrapancreatic nerve plexus,causing severe pain and retropancreatic tumor extension. It precludes curative resection, promotes local recurrence, and at the last negatively influences the prognosis of patients. Recent research on PNI in PCa has revealed the critical involvement of numerous nerve- or cancer cell-derived molecules in vitro and in vivo. However, the mechanisms contributing to alteration and invasion of intrapancreatic nerves and the spread of cancer cells along extrapancreatic nerves in pancreatic cancer patients are still poorly understood. This review focuses on perineural invasion in pancreatic cancer and provides an outline of the characteristics and molecular mechanisms of perineural invasion in pancreatic cancer.     

Lack of association between the functional CX3CR1 polymorphism V249I and hepatocellular carcinoma

Chemokine production by cancer cells constitutes a duality. Leukocyte recruitment under the pressure of chemokines may be beneficial for the host or for the tumor. Recently, the chemokine fractalkine and its receptor CX3CR1 have been shown to be expressed in hepatocytes in vivo and in a human hepatocarcinoma cell line in vitro. Therefore, the aim of this study was to analyze the expression of CX3CR1 in hepatocellular carcinoma (HCC) in vivo and to investigate the prevalence of the genetic CX3CR1 polymorphism V249I in HCC patients since this polymorphism has been associated with reduced number of fractalkine binding sites, reduced cell-cell adhesion and decreased signaling and chemotaxis. Genotyping was performed in 183 patients with histologically proven HCC and 99 healthy controls by RFLP-analysis. The frequency of the individual genotypes was similar in HCC patients and controls. The V249I polymorphism revealed no association with tumor grade and stage, the presence of extrahepatic metastasis or the degree of fibrosis in non-tumorous tissue. In addition to genotyping, CX3CR1 mRNA expression was analyzed by quantitative PCR in 9 HCC specimens and in 6 cases in corresponding non-tumorous liver tissues. CX3CR1 mRNA expression levels in HCC showed high variation between individual patients. Similarly, expression in HCC compared to non-tumorous liver varied, from strong downregulation to remarkable upregulation. CX3CR1 mRNA expression levels showed no correlation to the V249I polymorphism. In summary, these results suggest that the patho-physiological role of individual chemokines in carcinogenesis may vary and that the functional CX3CR1 polymorphism V249I is no genetic risk factor for HCC. However, additional independent studies in HCC patients with different ethnic background will be needed to confirm the present study and to elucidate the functional role of CX3CR1 and its polymorphism V249I in chronic liver disease and hepatocarcinogenesis.     

Perineural invasion in pancreatic cancer: Advanced research in the neuro-cancer interactions

Pancreatic Cancer (PCa) is characterized by prominently local nerve alterations and perineural invasion (PNI), which frequently aff ects the extrapancreatic nerve plexus, causing severe pain and retropancreatic tumor extension. It precludes curative resection, promotes local recurrence, and at the last negatively influences the prognosis of patients. Recent research on PNI in PCa has revealed the critical involvement of numerous nerve- or cancer cell-derived molecules in vitro and in vivo. However, the mechanisms contributing to alteration and invasion of intrapancreatic nerves and the spread of cancer cells along extrapancreatic nerves in pancreatic cancer patients are still poorly understood. This review focuses on perineural invasion in pancreatic cancer and provides an outline of the characteristics and molecular mechanisms of perineural invasion in pancreatic cancer.     

Fractalkine-CX3CR1 axis regulates tumor cell cycle and deteriorates prognosis after radical resection for hepatocellular carcinoma

BACKGROUND AND OBJECTIVES: Fractalkine is the only CX3C chemokine, and its receptor, CX3CR1, is expressed on NK cells, CD8+ T cells, monocytes, and dendritic cells (DC). Although studies have reported that fractalkine regulates the host immune response, the roles of the fractalkine-CX3CR1 axis in tumor biology and the clinical results of hepatocellular carcinoma (HCC) remain unknown. METHODS: Fractalkine and CX3CR1 expression in HCC were evaluated and compared with the clinicopathologic features, including tumor progression determined by proliferating cell nuclear antigen (PCNA) antibody and patient prognosis after surgery. RESULTS: Tumors with high expression of both fractalkine and CX3CR1 had significantly fewer intra- and extrahepatic recurrences, a low PCNA labeling index (PCNALI), and different histological grades. Patients with tumors that expressed both had a significantly better prognosis in terms of disease-free (DFS) and overall survival (OAS), and this finding was identified as one of the independent prognostic factors in the multivariate analysis. CONCLUSIONS: Our results suggest that the fractalkine-CX3CR1 axis plays a pivotal role in the prognosis of patients with HCC, which might arise from the known modulation of the host immune response, and that of the cell cycle in HCC.     

In vivo two-photon characterization of tumor-associated macrophages and microglia (TAM/M) and CX3CR1 during different steps of brain metastasis formation from lung cancer

Brain metastases frequently occur in lung cancer and dramatically limit prognosis of affected patients. The influence of tumor-associated macrophages and microglia (TAM/M) and their receptor CX3CR1 on different steps of brain metastasis formation from lung cancer is poorly characterized. We established a syngeneic orthotopic cerebral metastasis model in mice by combining a chronic cranial window with repetitive intravital 2-photon laser scanning microscopy. This allowed in vivo tracking of fluorescence-expressing tumor cells and TAM/M on a single-cell level over weeks. Intracarotid injection of red tdTomato-fluorescent Lewis lung carcinoma cell was performed in transgenic mice either proficient or deficient for CX3CR1. After intracarotid cell injection, intravascular tumor cells extravasated into the brain parenchyma and formed micro- and mature macrometastases. We observed potential phagocytosis of extravasated tumor cells by TAM/M. However, during later steps of metastasis formation, these anti-tumor effects diminished and were paralleled by TAM/M accumulation and activation. Although CX3CR1 deficiency resulted in a lower number of extravasated tumor cells, progression of these extravasated cells into micro metastases was more efficient. Overall, this resulted in a comparable number of mature macrometastases in CX3CR1-deficient and -proficient mice. Our findings indicate that unspecific inhibition of CX3CR1 might not be a suitable therapeutic option to prevent dissemination of lung cancer cells to the brain. Given the close interaction between TAM/M and tumor cells during metastasis formation, other therapeutic approaches targeting TAM/M function may warrant further evaluation. The herein established orthotopic mouse model may be a useful tool to evaluate such concepts in vivo.     

DJ-1 promotes invasion and metastasis of pancreatic cancer cells by activating SRC/ERK/uPA

A major hallmark of pancreatic ductal adenocarcinoma (PDAC) is extensive local tumor invasion and early systemic dissemination. DJ-1 has been shown to prevent cell death via the Akt pathway, thereby playing an important role in cancer progression and Parkinson's disease development. Here, we investigated the role of DJ-1 in tumor invasion and metastasis of pancreatic cancer and showed that DJ-1 is upregulated in 68.5% of pancreatic cancer specimens, correlated with tumor stage and predictive of short overall survival. Knockdown of DJ-1 expression in two PDAC cell lines reduced cell migration and invasion potential in vitro and inhibited metastasis in vivo. Knockdown of DJ-1 led to cytoskeleton disruption and diminished urokinase plasminogen activator (uPA) activity and expression, without affecting plasminogen activator inhibitor-1 and uPA receptor (uPAR) expression. All these effects were reversed by restoration of DJ-1 expression. In determining the pathway through which DJ-1 regulated cell migration and invasion, DJ-1 was found not to regulate Akt phosphorylation. Rather, it promoted extracellular signal-regulated kinase (ERK) and SRC phosphorylation. Inhibition of the ERK pathway in PDAC mimicked the effects of DJ-1 on cell migration, invasion, actin cytoskeleton and uPA/uPAR system and abolished the effects on promoting PDAC cell invasion and migration. These data represent the first identification of an important function of DJ-1, which is to regulate the invasion and metastasis properties of PDAC through the ERK/uPA cascade.     

低氧诱导因子HIF-1α调控CX3CR1在胰腺癌细胞中的表达

  目的  以胰腺癌细胞株Patu8988为研究对象, 通过过表达和干扰低氧诱导因子(HIF-1α), 观察CX3CR1表达水平的变化, 并探讨CX3CR1在胰腺癌中的调控机制。  方法  分别构建pcDNA3.1-HIF-1α过表达质粒和HIF-1α-siRNA, 转染胰腺癌细胞株Patu8988, 经Western blot、半定量PCR检测CX3CR1的表达情况。采用染色质免疫沉淀(chromatin immunoprecipitation, ChIP)、荧光素酶技术探查HIF-1α与CX3CR1启动子区的结合情况。  结果  Patu8988转染pcDNA3.1-HIF-1α后CX3CR1的表达增加, 敲除HIF-1α后CX3CR1的表达减少。HIF-1α与CX3CR1启动子区的低氧反应元件直接结合, 并上调CX3CR1启动子的活性(P < 0.01)。  结论  HIF-1α调控CX3CR1在胰腺癌细胞中的表达。      

A KrasG12D-driven genetic mouse model of pancreatic cancer requires glypican-1 for efficient proliferation and angiogenesis

Pancreatic ductal adenocarcinomas (PDACs) exhibit multiple molecular alterations and overexpress heparin-binding growth factors (HBGFs) and glypican-1 (GPC1), a heparan sulfate proteoglycan that promotes efficient signaling by HBGFs. It is not known, however, whether GPC1 has a role in genetic mouse models of PDAC. Therefore, we generated a GPC1 null mouse that combines pancreas-specific Cre-mediated activation of oncogenic Kras (Kras(G12D)) with deletion of a conditional INK4A/Arf allele (Pdx1-Cre;LSL-Kras(G12D);INK4A/Arf(lox/lox);GPC1(-/-) mice). By comparison with Pdx1-Cre;LSL-Kras(G12D);INK4A/Arf(lox/lox) mice that were wild type for GPC1, the Pdx1-Cre;LSL-Kras(G12D);INK4A/Arf(lox/lox);GPC1(-/-) mice exhibited attenuated pancreatic tumor growth and invasiveness, decreased cancer cell proliferation and mitogen-activated protein kinase activation. These mice also exhibited suppressed angiogenesis in conjunction with decreased expression of messenger RNAs encoding several pro-angiogenic factors and molecules, including vascular endothelial growth factor-A (VEGF-A), SRY-box containing gene (SOX17), chemokine C-X3-C motif ligand 1 (CX3CL1) and integrin β3 (ITGB3). Moreover, pancreatic cancer cells isolated from the tumors of GPC1(-/-) mice were not as invasive in response to fibroblast growth factor-2 (FGF-2) as cancer cells isolated from wild-type mice, and formed smaller tumors that exhibited an attenuated metastatic potential. Similarly, VEGF-A and FGF-2 did not enhance the migration of hepatic endothelial cells and immortalized murine embryonic fibroblasts isolated from GPC1 null mice. These data demonstrate in an oncogenic Kras-driven genetic mouse model of PDAC that tumor growth, angiogenesis and invasion are enhanced by GPC1, and suggest that suppression of GPC1 may be an important component of therapeutic strategies in PDAC.