BACKGROUND: The epidermal growth factor receptor (EFGR) mutation was closely related to the invasion and metastasis of lung adenocarcinoma and the biological axis of CXCR4/CXCL12 (chemokine receptor 4/chemokine ligand 12) played an important role in the organ-specific metastasis of the tumor. It was a question surrounding whether there is interaction between them in the process of lung adenocarcinoma metastasis. To investigate the potential molecular mechanisms of EGFR over-expression and EFGR-mutations effects on cell proliferation, migration and invasion, we constructed EGFR over-expression and three EFGR-mutant human lung adenocarcinoma H1299 cell sublines. METHODS: EGFR over-expression and three EFGR-mutant (EGFR-E746-A750del, EGFR-T790M and EGFR-L858R) plasmid were designed and transfected H1299 cells with Lipofectamine 2000. H1299 cells transfected with empty vector were negative control (NC), and H1299 cells without transfection were set as blank control (BC). The effects of EGFR over-expression and mutations on the proliferation, migration and invasion of H1299 cells were detected by cell cloning assay, wound healing assay and Transwell assay. The mRNA and protein expression levels of MMP-2, MMP-9, CXCR4 and CXCL12 were detected by RT-PCR and Western blot. RESULTS: Compared with negative control group and blank control group, EGFR over-expression and EGFR-E746-A750 deletion have significantly higher colony formation (28±2, 28.33±4.16; respectively) (P<0.05) and the cell migration and invasion ability were significantly increased (P<0.05). RT-PCR and Western blot assay showed that the mRNA and protein expression of MMP-2, MMP-9, CXCR4 and CXCL12 in EGFR over-expression and EGFR-E746-A750 deletion group were remarkably higher than that in negative control and blank control group (P<0.05). CONCLUSIONS EGFR over-expression and 19 exon deletion can promote the expression of MMP-2 and MMP-9 by up-regulating CXCR4/CXCL12 signaling pathway, leading to the change of tumor biological characteristics such as higher proliferation, migration and invasion ability.
Adenocarcinoma ; pathology ; Adenocarcinoma of Lung ; Cell Line, Tumor ; Cell Movement ; genetics ; Chemokine CXCL12 ; metabolism ; ErbB Receptors ; genetics ; Gene Expression Regulation, Neoplastic ; Humans ; Lung Neoplasms ; pathology ; Mutation ; Neoplasm Invasiveness ; Receptors, CXCR4 ; metabolism ; Signal Transduction ; genetics

Chemokine 12 (CXCL12), also known as stromal cell derived factor-1 (SDF-1) and a member of the CXC chemokine subfamily, is ubiquitously expressed in many tissues and cell types. It interacts specifically with the ligand for the transmembrane G protein-coupled receptors CXCR4 and CXCR7. The CXCL12/CXCR4 axis takes part in a series of physiological, biochemical, and pathological process, such as inflammation and leukocyte trafficking, cancer-induced bone pain, and postsurgical pain, and also is a key factor in the cross-talking between tumor cells and their microenvironment. Aberrant overexpression of CXCR4 is critical for tumor survival, proliferation, angiogenesis, homing and metastasis. In this review, we summarized the role of CXCL12/CXCR4 in cancer, CXCR4 inhibitors under clinical study, and natural product CXCR4 antagonists. In conclusion, the CXCL12/CXCR4 signaling is important for tumor development and targeting the pathway might represent an effective approach to developing novel therapy in cancer treatment.
Animals ; Antineoplastic Agents ; chemical synthesis ; chemistry ; pharmacology ; Biological Products ; chemistry ; pharmacology ; Chemokine CXCL12 ; genetics ; metabolism ; Humans ; Molecular Targeted Therapy ; Neoplasms ; drug therapy ; genetics ; metabolism ; Receptors, CXCR4 ; antagonists & inhibitors ; genetics ; metabolism

OBJECTIVETo investigate the expression of ALDH1, CXCR4 and E-cadherin in gastric carcinoma and their roles in lymphatic metastasis.

METHODSSurgical specimens from 127 cases of gastric carcinoma were examined for expressions of ALDH1, CXCR4 and E-cadherin immuohistochemistry with 60 adjacent tissues as control. The associations of ALDH1, CXCR4 and E-cadherin with the clinicopathological pfeatures, 5-year survival rate and lymph node metastasis of the patients were analyzed.

RESULTSALDH1, CXCR4 and E-cadherin were positive in 57.5% (73/127), 63.8% (81/127), and 36.2% (46/127) of the gastric carcinoma tissues, respectively, showing significant differences from the rates in the adjacent tissues (P<0.05). The expression of ALDH1 was significantly correlated with TNM stage and lymph node metastasis (P<0.05), CXCR4 was significantly correlated with the invasion depth, differentiation, TNM stage and lymph node metastasis of the tumor (P<0.05), and E-cadherin was significantly correlated with the invasion depth, differentiation and lymph node metastasis (P<0.05). The positivity rates of ALDH1, CXCR4 and E-cadherin were higher in cases with lymph node metastasis than in those without metastasis. E-cadherin expression was inversely correlated with ALDH1 and CXCR4 expression, and the latter two were positively correlated (P<0.001). Overexpressions of ALDH1 and CXCR4 and a decreased expression of E-cadherin were all related to a poor prognosis of the patients (P<0.05). The expressions ofALDH1, CXCR4 and E-cadherin were all independent prognostic factors of gastric carcinoma.

CONCLUSIONThe expressions of ALDH1, CXCR4 and E-cadherin are associated with the invasion, metastasis and prognosis of gastric carcinoma, and their combined detection provides important evidence for predicting the progression and prognosis of gastric carcinoma.

Cadherins ; genetics ; metabolism ; Carcinoma ; genetics ; metabolism ; Disease Progression ; Humans ; Isoenzymes ; genetics ; metabolism ; Lymphatic Metastasis ; Prognosis ; Receptors, CXCR4 ; genetics ; metabolism ; Retinal Dehydrogenase ; genetics ; metabolism ; Stomach Neoplasms ; genetics ; metabolism ; Survival Rate

OBJECTIVETo investigate the effect of CXCR4 gene on the proliferation, adhesion, invasion and tumorigenicity of a human monocytic leukemic cell line SHI-1.

METHODSThe lentivirus vector silencing the expression of CXCR4 was constructed for infection of SHI-1 cells silencing expression of CXCR4 in SHI-1 cells. The expression of CXCR4, MMP-2 and MMP-9 was detected by real time PCR. The expression of CXCR4 on membrane of SHI-1 cells was detected by flow cytometry. The SHI-1 cell proliferation ability was detected by MTT. The co-culture system of the leukemia cells and bone marrow stromal cells was used to detect the adhesion and migration ability of leukemia cells. SHI-1 cells were inoculated subcutaneously in nude mice to investigate the growth ability in vivo.

RESULTSAfter SHI-1 cells were infected by lentivirus silencing expression of CXCR4, the expression of CXCR4 mRNA in SHI-1 CXCR-4i cells decreased by 76% as compared with expression of SHI-1/NC of negative control virus, the expression of CXCR4 on membrane of SHI-1/CXCR4i obviously downregulated; the expression of MMP-2 and MMP-9 in SHI-1/CXCRi cells also declined by 63% and 62% respectively; the proliferation ability of SHI-1/CXCR4i in vitro did not obviously changed, but the adhesion and trans-matrigel invasion ability significantly decreased, the SHI-1/CXCR4i cells could not form neoplasm subcutaneously in mice, but the SHI-1 and SHI-1/NC cells could form neoplasm subcutaneously in mice, and there was no significant difference in volumn of neoplasm mass.

CONCLUSIONThe silencing expression of CXCR4 can decline the adhesion and migration ability of SHI-1 cells, and can completely suppress the formation of neoplasm subcutaneously, so the CXCR4 may serve as a target for treating leukemia.

Animals ; Cell Adhesion ; Cell Line, Tumor ; Cell Proliferation ; Coculture Techniques ; Humans ; Lentivirus ; Leukemia, Monocytic, Acute ; pathology ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Mesenchymal Stromal Cells ; Mice ; Mice, Nude ; Neoplasm Invasiveness ; RNA Interference ; RNA, Messenger ; Receptors, CXCR4 ; genetics ; Signal Transduction

This study was purposed to establish the mesenchymal stem cells (MSCs) stably overexpressing mouse CXC chemokine receptor type 4 (CXCR4) gene and to explore their function. The recombinant lentiviral vector LV-CXCR4-IRES-EGFP with packaging plasmid pSPAX2 and envelope plasmid pMD.2G were co-transfected into 293FT packaging cell line using lipofectamine 2000 to produce the recombinant lentiviral vectors. The recombinant viruses were harvested and concentrated by using ultracentrifugation. Mouse bone marrow MSC were infected with the viral supernatants. Variable methods were used to optimize the transduction condition. EGFP expression was visualized using fluorescence microscope and efficiency of infection was determined by flow cytometry (FCM). Proliferation and apoptosis were detected by proliferation curve and FCM, respectively. Migration capacity was assessed by a chemotaxis assay using transwell. Expression of EGFP were detected by fluorescence microscopy in MSCs after infection. The results showed that through optimization of infection condition, the recombination lentiviral vectors had higher infection efficacy; after infection for 72 h, the higher expression of EGFP could be observed under fluorescence microscope; the expression of CXCR4 protein on MSC surface in CXCR4-MSC group significantly increased compared with those in the control group. Meanwhile, over-expression of CXCR4 had no effect on their capacity of proliferation and did not induce apoptosis. Moreover, CXCR4 enhanced the migration of cells in the transwell induced by SDF-1 gradient compared with the EGFP control group. It is concluded that the lentiviral vector can not only infect mouse MSCs efficiently, but also can make CXCR4 express stably in MSC.
Animals ; Apoptosis ; Cell Line ; Chemokine CXCL12 ; Flow Cytometry ; Genetic Vectors ; Lentivirus ; Mesenchymal Stromal Cells ; metabolism ; Mice ; Plasmids ; Receptors, CXCR4 ; genetics ; Transfection

The transplantation of neural precursor cells (NPCs) is known to be a promising approach to ameliorating behavioral deficits after stroke in a rodent model of middle cerebral artery occlusion (MCAo). Previous studies have shown that transplanted NPCs migrate toward the infarct region, survive and differentiate into mature neurons to some extent. However, the spatiotemporal dynamics of NPC migration following transplantation into stroke animals have yet to be elucidated. In this study, we investigated the fates of human embryonic stem cell (hESC)-derived NPCs (ENStem-A) for 8 weeks following transplantation into the side contralateral to the infarct region using 7.0T animal magnetic resonance imaging (MRI). T2- and T2*-weighted MRI analyses indicated that the migrating cells were clearly detectable at the infarct boundary zone by 1 week, and the intensity of the MRI signals robustly increased within 4 weeks after transplantation. Afterwards, the signals were slightly increased or unchanged. At 8 weeks, we performed Prussian blue staining and immunohistochemical staining using human-specific markers, and found that high percentages of transplanted cells migrated to the infarct boundary. Most of these cells were CXCR4-positive. We also observed that the migrating cells expressed markers for various stages of neural differentiation, including Nestin, Tuj1, NeuN, TH, DARPP-32 and SV38, indicating that the transplanted cells may partially contribute to the reconstruction of the damaged neural tissues after stroke. Interestingly, we found that the extent of gliosis (glial fibrillary acidic protein-positive cells) and apoptosis (TUNEL-positive cells) were significantly decreased in the cell-transplanted group, suggesting that hESC-NPCs have a positive role in reducing glia scar formation and cell death after stroke. No tumors formed in our study. We also performed various behavioral tests, including rotarod, stepping and modified neurological severity score tests, and found that the transplanted animals exhibited significant improvements in sensorimotor functions during the 8 weeks after transplantation. Taken together, these results strongly suggest that hESC-NPCs have the capacity to migrate to the infarct region, form neural tissues efficiently and contribute to behavioral recovery in a rodent model of ischemic stroke.
Animals ; Apoptosis ; Cell Differentiation ; *Cell Movement ; Embryonic Stem Cells/cytology/metabolism/*transplantation ; Glial Fibrillary Acidic Protein/genetics/metabolism ; Humans ; Infarction, Middle Cerebral Artery/metabolism/pathology/physiopathology/*surgery ; Male ; Neural Stem Cells/cytology/metabolism/*transplantation ; *Psychomotor Performance ; Rats ; Rats, Sprague-Dawley ; Receptors, CXCR4/genetics/metabolism

OBJECTIVEThis review focuses on the state-of-the-art of CXCL12/CXCR4 signaling axis in pancreatic cancer and its role in tumor progression.

DATA SOURCESRelevant articles published in English were identified by searching in Pubmed from 1997 to 2013, with keywords "CXCL12", "CXCR4" and "pancreatic cancer". Important references from selected articles were also retrieved.

STUDY SELECTIONArticles about CXCL12/CXCR4 signaling axis in pancreatic cancer and relevant mechanisms were selected.

RESULTSPancreatic cancer has been one of the most lethal human malignancies, with median survival less than one year and overall 5-year survival only 6%. Tumor cells from pancreatic cancer express high level of CXCR4. CXCL12, the ligand for CXCR4, is extensively secreted by neighboring stromal cells and other distant organs. CXCL12 primarily binds to CXCR4, induces intracellular signaling through several divergent pathways, which are involved in progression and metastasis of pancreatic cancer.

CONCLUSIONSCXCL12/CXCR4 signaling axis may play an important role in the communication between pancreatic cancer cells and their microenvironment, which may have effect on tumor proliferation, invasion, angiogenesis, metastasis and chemoresistance. CXCL12/CXCR4 signaling axis may serves as a novel therapeutic target for pancreatic cancer.

Chemokine CXCL12 ; genetics ; metabolism ; Humans ; Pancreatic Neoplasms ; genetics ; metabolism ; Receptors, CXCR4 ; genetics ; metabolism ; Signal Transduction ; genetics ; physiology

OBJECTIVETo construct mouse CXC chemokine receptor type 4 (Cxcr4) gene overexpressing lentiviral vector and to evaluate its biological effect on mouse mesenchymal stem cells (MSCs).

METHODSCxcr4 gene was amplified and subcloned into pCR-Blunt vector. Cxcr4 gene and enhanced green fluorescent protein (EGFP) gene expressed bicistronic recombinant lentiviral vector LV-CXCR4-IRES-EGFP and control vector LV-IRES-EGFP were constructed, respectively. Both plasmids were co-transfected into 293FT packaging cell line with packaging plasmid pSPAX2 and enveloping plasmid pMD.2G using Lipofectamine 2000 to produce lentiviral virus, respectively. The recombinant viruses were harvested and the virus titer was determined by limiting dilution. Mouse MSCs were infected with viral supernatant. EGFP expression was visualized using fluorescence microscope and efficiency of infection was determined by flow cytometry (FCM). Cell counting kit-8 (CCK-8) was applied in mixed lymphocyte reaction (MLR) to evaluate the suppressive effect of MSCs on mice splenocyte proliferation in vitro. Wound healing ability of MSCs was measured by scratch experiment and migration capacity by a chemotaxis assay using a transwell assay.

RESULTSThe Cxcr4 fragment was amplified by reverse transcription polymerase chain reaction (RT-PCR) and verified by DNA sequencing. The restriction enzyme digestion experiment demonstrated that the recombinant lentiviral vector LV-CXCR4-IRES-EGFP and the control vector LV-IRES-EGFP were successfully constructed. Expression of CXCR4 was detected by fluorescence microscopy, which indicated that the lentiviral particles expressing CXCR4 were packaged. Furthermore, expression of EGFP were detected by fluorescence microscopy in MSCs after infection and the expression of CXCR4 protein on MSCs surface in CXCR4-MSC group was significantly increased comparing to those in the control group(P < 0.05).CXCR4-MSCs group and the control group were (90.3 ± 3.37)% and (1.53 ± 0.34)%, respectively. Meanwhile, overexpression of CXCR4 had no effect on their capacity of immune regulation when co-cultured with splenocyte(P > 0.05). Moreover, overexpression of CXCR4 can not only accelerated the wound healing after scratch, but also enhanced the migration ability of cells in the transwell induced by high concentration of SDF-1 in a dose-dependent manner compared with the EGFP control group.

CONCLUSIONThe CXCR4 expressing lentiviral vector LV-CXCR4-IRES-EGFP was successfully constructed. The lentiviral vector can not only efficiently infect mouse MSCs, but also stably express CXCR4 in MSCs. The MSCs modified with CXCR4 have biological characteristic in vitro.

Animals ; Cell Line ; Genetic Vectors ; Lentivirus ; genetics ; Mesenchymal Stromal Cells ; metabolism ; pathology ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Receptors, CXCR4 ; genetics

This study was purposed to explore the expression of p57kip2 in the bone marrow of patients with de novo myelodysplastic syndrome (MDS) and its role in MDS pathogenesis, as well as the relationship between the expression of p57kip2 and SDF-1/CXCR4 signal. The expression of p57kip2 and CXCR4 in 67 de novo MDS patients was measured by real-time quantitative PCR. The percentage of CD34(+) cells in the bone marrow from MDS patients was measured by flow cytometry. 18 healthy volunteers were recruited for control. The effect of SDF-1 on p57kip2 expression in bone marrow mononuclear cell (BMMNC) from MDS or normal controls was investigated in vitro, and difference between them was compared. The results showed that low-risk MDS and high-risk MDS displayed a significant reduction of p57kip2 mRNA expression in BMMNC compared with that in control group (P < 0.001) and there was a negative correlation between p57kip2 expression and percentage of CD34(+) (r = -0.458, P < 0.001); the patients with abnormal karyotype showed lower expression of p57kip2 gene, compared to patients with normal karyotype (P = 0.045). Although the expression of CXCR4 had no difference between MDS patients and normal controls, a positive correlation between p57kip2 and CXCR4 in MDS patients was still found (r = 0.609, P < 0.001). Moreover, SDF-1 increased p57kip2 expression in normal BMMNC in dose-dependent manner, but BMMNC from MDS patients showed no response to SDF-1. SDF-1-induced p57 expression was blocked by AMD3100. It is concluded that the low expression of p57 gene in MDS may play a role in the pathogenesis of MDS. Furthermore, SDF-1-induced p57kip2 expression in BMMNC, and the decreasing response of BMMNC to SDF-1 may contribute to the low expression of p57kip2 in MDS patients.
Case-Control Studies ; Chemokine CXCL12 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p57 ; genetics ; metabolism ; Flow Cytometry ; Humans ; Myelodysplastic Syndromes ; genetics ; metabolism ; Receptors, CXCR4 ; metabolism

OBJECTIVETo obtain a specific antagonist of CXCR4, SDF-1P2G54 by mutating SDF-1 second proline (P) into glycin (G) and removing the α-helix of its C-terminal.

METHODSSDF-1p2g54 gene amplified by PCR was inserted into the vector pET-30a (+) and transformed into Escherichia coli (E. coli) strain BL21. After IPTG induction of E. coli, the expressed recombinant protein was purified with nickel-affinity chromatography column under denaturing conditions and refolded with gradient dilution and ultra-filtration. The chemotactic effect of SDF-1P2G54 on Jurkat cells and its antagonistic effect against SDF-1 were determined by transwell assay; flow cytometry was used to assay the ability of SDF-1P2G54 to induce calcium influx and CXCR4 internalization in MOLT4 cells.

RESULTSThe recombinant protein SDF-1P2G54 completely lost the functions to activate CXCR4 or to induce transmembrane migration of Jurkat cells and calcium influx in MOLT4 cells, but maintained a high affinity to CXCR4. SDF-1P2G54 effectively inhibited the chemotactic effect of wild-type SDF-1 to Jurkat cells, and induced rapid CXCR4 internalization in MOLT4 cells.

CONCLUSIONSDF-1P2G54 is a new antagonist of CXCR4 with a potential value as an effective inhibitor of HIV-1 infection, cancer metastasis or other major diseases.

Cell Line ; Chemokines, CXC ; biosynthesis ; genetics ; Escherichia coli ; genetics ; metabolism ; Humans ; Mutant Proteins ; biosynthesis ; genetics ; Receptors, CXCR4 ; antagonists & inhibitors ; Recombinant Proteins ; biosynthesis ; genetics