CXC Chemokine Receptor 4 Expression Research Articles

Circulating tumour cells and their association with bone metastases in patients with neuroendocrine tumours

BackgroundBone metastases are associated with a worse outcome in patients with neuroendocrine tumours (NETs). Tumour overexpression of C-X-C chemokine receptor 4 (CXCR4) appears predictive of skeletal involvement. We investigated the role of circulating tumour cells (CTCs) and CXCR4 expression on CTCs as potential predictors of skeleton invasion.MethodsBlood from patients with metastatic bronchial, midgut or pancreatic NET (pNET) was analysed by CellSearch. CXCR4 immunohistochemistry was performed on matched formalin-fixed paraffin-embedded (FFPE) samples.ResultsTwo hundred and fifty-four patients were recruited with 121 midgut and 119 pNETs, of which 51 and 36% had detectable CTCs, respectively. Bone metastases were reported in 30% of midgut and 23% of pNET patients and were significantly associated with CTC presence (p = 0.003 and p < 0.0001). In a subgroup of 40 patients, 85% patients with CTCs had CTCs positive for CXCR4 expression. The proportion of CXCR4-positive CTCs in patients with bone metastases was 56% compared to 35% in those without (p = 0.18) it. Staining for CXCR4 on matched FFPE tissue showed a trend towards a correlation with CXCR4 expression on CTCs (p = 0.08).ConclusionsCTC presence is associated with bone metastases in NETs. CXCR4 may be involved in CTC osteotropism and present a therapeutic target to reduce skeletal morbidity.

LPS-induced CXCR7 expression promotes gastric Cancer proliferation and migration via the TLR4/MD-2 pathway

BackgroundLipopolysaccharide (LPS) from Helicobacter pylori (HP) plays an important role in gastric cancer occurrence and development. Toll-like receptor 4 (TLR4) and myeloid differential protein-2 (MD-2) are also reported to be involved in gastric cancer cell proliferation and invasion. CXC chemokine receptor 7 (CXCR7), a second receptor for CXCL12, has been detected in multiple types of tumor tissues. Nevertheless, the biological function and regulation of CXCR7 and its relationship with TLR4 and MD-2 in gastric cancer are not completely understood and therefore warrant further study.MethodsCXCR7 expression was examined in 150 gastric cancer tissues using immunohistochemistry (IHC). RT-PCR and western blotting were used to detect CXCR7 expression in several gastric cancer cell lines (SGC7901, AGS, MGC-803, MKN-45 and BGC823). shRNAs were designed using a pGPU6/GFP/Neo vector. A CCK-8 assay was used to assess cell proliferation, and transwell assays were performed to assess cell migration. In addition, a gastric cancer xenograft model was generated.ResultsThe LPS-TLR4-MD-2 pathway elevates CXCR7 expression in SGC7901 cells, and TLR4/MD-2-mediated increases in CXCR7 levels modulate the proliferation and migration of tumor cells. Knockdown of TLR4 and MD-2 demonstrated that both are essential for LPS-induced CXCR7 expression, which in turn is responsible for LPS-induced SGC7901 cell proliferation and migration. Moreover, higher TLR4, MD-2 and CXCR7 expression was detected in gastric cancer tissues than in paracancerous normal control tissues. The expression levels of TLR4, MD-2 and CXCR7 were closely related to gastric cancer TNM stage and lymph node metastasis. In an animal model, significant differences in CXCR7 expression in tumor masses were observed between the control group and experimental group.ConclusionsThe results of this study indicate that CXCR7 plays an important role in gastric cancer progression via inflammatory mechanisms, suggesting that CXCR7 could provide a basis for the development and clinical application of a targeted drug for gastric cancer.

A dual modality 99mTc/Re(i)-labelled T140 analogue for imaging of CXCR4 expression.

The C-X-C chemokine receptor 4 (CXCR4) has been shown to be overexpressed in at least 23 types of cancer, including prostate cancer which has been shown to have a significant distinction of expression rates between cancerous compared to healthy or benign tissue. In an attempt to exploit the difference in expression, we have synthesized a derivative of T140, a peptide antagonist for CXCR4, containing a fluorescent 4-amino-1,8-naphthalimide appended with a di-(2-picolyl)amine binding unit to chelate rhenium or technetium-99m for fluorescence or SPECT imaging. The rhenium-coordinated variant was shown to have similar binding affinity for the receptor as T140 and showed specific uptake by fluorescence microscopy in CXCR4 expressing cells. The peptide was radiolabelled with technetium-99m in decay corrected radiochemical yields ranging from 60-85%, radiochemical purities >95%, and molar activities of 36-44 GBq μmol-1. The technetium-99m labelled peptide showed two-fold higher uptake in U87 cells expressing CXCR4 compared to non-transfected cells. Ex vivo biodistribution studies were performed using the technetium-99m labelled peptide in NOD/SCID mice bearing tumors derived from U87 cells with CXCR4. Tumor uptake of 0.51 ± 0.09% ID g-1 was observed two-hours post-injection. Our novel T140 derivative is suitable for imaging of CXCR4 expression by confocal microscopy. Further structural modifications to the peptide or metal complex may result in improved biodistribution for use in SPECT imaging of CXCR4 expressing tumors.

Expression of CXC Chemokine Receptors in Acute Ulcerative Colitis: Initial Study from an Animal Model.

Background:Ulcerative colitis (UC) is an inflammatory disease which is characterized by infiltration of inflammatory cells, crypt abscesses, distortion of the mucosal glands, and goblet cell depletion. The existence of neutrophil-rich inflammation in colon tissues of patients with UC is one of the most significant histological features of this disease. Nonetheless, the expression of CXCR chemokine receptors which appear as the main chemical mediators governing the migration of neutrophils into the mucosal tissue of patients with UC has not been well clarified.Materials and Methods:In this experimental study, the UC model was induced in Wistar rats by administration of 2 ml 4% acetic acid into the large colon through the rectum. Animals were anesthetized after 48 h; their colon tissue samples were isolated for macroscopic and histopathological examination. The expression of receptor1-7 of CXC chemokine was assessed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) technique.Results:Heavy infiltration of neutrophils, coagulative necrosis, and ulcers were observed in H and E staining, which pathologically proved the UC model. qRT-PCR results indicated that CXCR2 as one of the important ELR+ chemokine family receptors bears the highest expression in the UC group (32 fold) than the control group (P ≤ 0.05). In addition, other CXCRs of this group including CXCR1 did not possess any change (P > 0.05). In contrast, RLR negative chemokine family receptors did not show any changes with the normal group.Conclusion:The results showed that CXCR2 is the only receptor for CXCL family which was remarkably upregulated in experimental UC and that CXCR2 might play a significant role in the pathogenesis of UC.

AMD3100 inhibits epithelial-mesenchymal transition, cell invasion, and metastasis in the liver and the lung through blocking the SDF-1α/CXCR4 signaling pathway in prostate cancer.

Stromal cell-derived factor-1 (SDF-1) and CXC chemokine receptor 4 (CXCR4) have been found to be tightly correlated with the progression of prostate cancer (PC). In this study, we investigated the effects of an SDF-1α/CXCR4 inhibitor, AMD3100, on cell progression and metastasis potential of human PC cells. Human PC cell lines (LNCaP, PC3, and DU145) were cultured to detect SDF-1α/CXCR4, which showed higher SDF-1α and CXCR4 expression than the normal human prostate epithelial cell line, RWPE-1. AMD3100 was confirmed to be an inhibitor of SDF-1α, and to detect the effect of SDF-1α/CXCR4 inhibition on PC, PC cells were treated with AMD3100 or/and CXCR4 siRNA. The results suggested that inhibition of the SDF-1α/CXCR4 pathway could promote the E-cadherin level but inhibit the levels of invasion and migration of vimentin, N-cadherin and α5β1 integrin. Finally, tumor formation in nude mice was conducted, and the cell experiment results were verfied. These data show that AMD3100 suppresses epithelial-mesenchymal transition and migration of PC cells by inhibiting the SDF-1α/CXCR4 signaling pathway, which provides a clinical target in the treatment of PC.

Modelling of the SDF-1/CXCR4 regulated in vivo homing of therapeutic mesenchymal stem/stromal cells in mice.

BackgroundMesenchymal stem/stromal cells (MSCs) are a promising tool for cell-based therapies in the treatment of tissue injury. The stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor 4 (CXCR4) axis plays a significant role in directing MSC homing to sites of injury. However in vivo MSC distribution following intravenous transplantation remains poorly understood, potentially hampering the precise prediction and evaluation of therapeutic efficacy.MethodsA murine model of partial ischemia/reperfusion (I/R) is used to induce liver injury, increase the hepatic levels of SDF-1, and study in vivo MSC distribution. Hypoxia-preconditioning increases the expression of CXCR4 in human bone marrow-derived MSCs. Quantitative assays for human DNA using droplet digital PCR (ddPCR) allow us to examine the in vivo kinetics of intravenously infused human MSCs in mouse blood and liver. A mathematical model-based system is developed to characterize in vivo homing of human MSCs in mouse models with SDF-1 levels in liver and CXCR4 expression on the transfused MSCs. The model is calibrated to experimental data to provide novel estimates of relevant parameter values.ResultsImages of immunohistochemistry for SDF-1 in the mouse liver with I/R injury show a significantly higher SDF-1 level in the I/R injured liver than that in the control. Correspondingly, the ddPCR results illustrate a higher MSC concentration in the I/R injured liver than the normal liver. CXCR4 is overexpressed in hypoxia-preconditioned MSCs. An increased number of hypoxia-preconditioned MSCs in the I/R injured liver is observed from the ddPCR results. The model simulations align with the experimental data of control and hypoxia-preconditioned human MSC distribution in normal and injured mouse livers, and accurately predict the experimental outcomes with different MSC doses.DiscussionThe modelling results suggest that SDF-1 in organs is an effective in vivo attractant for MSCs through the SDF-1/CXCR4 axis and reveal the significance of the SDF-1/CXCR4 chemotaxis on in vivo homing of MSCs. This in vivo modelling approach allows qualitative characterization and prediction of the MSC homing to normal and injured organs on the basis of clinically accessible variables, such as the MSC dose and SDF-1 concentration in blood. This model could also be adapted to abnormal conditions and/or other types of circulating cells to predict in vivo homing patterns.

Forkhead box C1 boosts triple‐negative breast cancer metastasis through activating the transcription of chemokine receptor‐4

The transcription factor forkhead box C1 (FOXC1) has recently been proposed as a crucial regulator of triple‐negative breast cancer (TNBC) and associated with TNBC metastasis. However, the mechanism of FOXC1 in TNBC development and metastasis is elusive. In this study, overexpression of FOXC1 in MDA‐MB‐231 cells significantly enhanced, whereas knockdown of FOXC1 in BT549 cells significantly reduced, the capabilities of TNBC cell invasion and motility in vitro and metastasis to the lung in vivo, when compared to their respective control cells. Mechanistic studies revealed that FOXC1 increased the expression of CXC chemokine receptor‐4 (CXCR4), probably through transcriptional activation. AMD3100, an inhibitor of CXCR4, could block cell migration. In a zebrafish tumor model, AMD3100 could suppress cell invasion and metastasis. In addition, overexpressing CXCR4 in FOXC1‐knockdown BT549 cells increased the capabilities of TNBC cell invasion and motility. In contrast, inhibition of CXCR4 with either AMD3100 or siRNA in MDA‐MB‐231 cells overexpressing FOXC1 reduced the capabilities of invasion and motility. Taken together, our results reveal a potential mechanism for FOXC1‐induced TNBC metastasis.

Berberine-Promoted CXCR4 Expression Accelerates Endothelial Repair Capacity of Early Endothelial Progenitor Cells in Persons with Prehypertension.

To evaluate whether the berberine treatment can improve endothelial repair capacity of early endothelial progenitor cells (EPCs) from prehypertensive subjects through increasing CXC chemokine receptor 4 (CXCR4) signaling. EPCs were isolated from prehypertensive and healthy subjects and cultured. In vivo reendothelialization capacity of EPCs from prehypertensive patients with or without in vitro berberine treatment was examined in a nude mouse model of carotid artery injury. The protein expressions of CXCR4/Janus kinase-2 (JAK-2) signaling of in vitro EPCs were detected by Western blot analysis. CXCR4 signaling and alteration in migration and adhesion functions of EPCs were evaluated. Basal CXCR4 expression was significantly reduced in EPCs from prehypertensive patients compared with normal subjects (P<0.01). Also, the phosphorylation of JAK-2 of EPCs, a CXCR4 downstream signaling, was significantly decreased (P<0.01). Berberine promoted CXCR4/JAK-2 signaling expression of in vitro EPCs (P<0.01). Transplantation of EPCs pretreated with berberine markedly accelerated in vivo reendothelialization (P<0.01). The increased in vitro function and in vivo reendothelialization capacity of EPCs were inhibited by CXCR4 neutralizing antibody or pretreatment with JAK-2 inhibitor AG490, respectively (P<0.01). Berberinemodified EPCs via up-regulation of CXCR4 signaling contributes to enhanced endothelial repair capacity in prehypertension, indicating that berberine may be used as a novel potential primary prevention means against prehypertension-related atherosclerotic cardiovascular disease.

Interleukin 8 (CXCL8)-CXC chemokine receptor 2 (CXCR2) axis contributes to MiR-4437-associated recruitment of granulocytes and natural killer cells in ischemic stroke

Granulocytes and natural killer (NK) cells have been linked to brain injury in ischemic stroke. However, their recruitment from peripheral leucocytes in stroke patients is not well understood. Here, the expression of the interleukin 8 (CXCL8) in plasma, and CXC chemokine receptor 2 (CXCR2) in peripheral leucocytes of patients with ischemic stroke were evaluated. Based on the results, CXCR2 expression positively correlated with granulocytes and NK cells, which were in turn attracted by CXCL8. The results also indicated that CXCR2 was a direct target of microRNA (miR)-4437, a negative regulator of CXCR2, which was downregulated in peripheral leucocytes from patients with ischemic stroke. Furthermore, serum CXCL8 levels were associated with the infarct volume and functional outcomes in patients with ischemic stroke. The results of the receiver operating characteristic curve analysis with an optimal cut-off value of 34 pg/mL indicated serum CXCL8 levels could be a prognostic indicator for ischemic stroke. In conclusion, these data highlighted the involvement of the CXCL8-CXCR2 chemotactic axis in the recruitment of granulocytes and NK cells in ischemic stroke. Furthermore, miR-4437 was suggested as a novel target for treating ischemic stroke, while the serum CXCL8 level could be a prognostic factor for ischemic stroke.

Danhong Injection Enhances the Therapeutic Efficacy of Mesenchymal Stem Cells in Myocardial Infarction by Promoting Angiogenesis

Stem cell-based therapies have the potential to dramatically transform the treatment and prognosis of myocardial infarction (MI), and mesenchymal stem cells (MSCs) have been suggested as a promising cell population to ameliorate the heart remodeling in post-MI. However, poor implantation and survival in ischemic myocardium restrict its efficacy and application. In this study, we sought to use the unique mode of action of Chinese medicine to improve this situation. Surrounding the myocardial infarct area, we performed a multi-point MSC transplantation and administered in conjunction with Danhong injection, which is mainly used for the treatment of MI. Our results showed that the MSC survival rate and cardiac function were improved significantly through the small animal imaging system and echocardiography, respectively. Moreover, histological analysis showed that MSC combined with DHI intervention significantly reduced myocardial infarct size in myocardial infarcted mice and significantly increased MSC resident. To investigate the mechanism of DHI promoting MSC survival and cell migration, PCR and WB experiments were performed. Our results showed that DHI could promote the expression of CXC chemokine receptor 4 in MSC and enhance the expression of stromal cell–derived factor-1 in myocardium, and this effect can be inhibited by AMD3100 (an SDF1/CXCR4 antagonist). Additionally, MSC in combination with DHI interfered with MI in mice and this signifies that when combined, the duo could the expression of vascular endothelial growth factor (VEGF) in the marginal zone of infarction compared with when either MSC or DHI are used individually. Based on these results, we conclude that DHI enhances the residence of MSCs in cardiac tissue by modulating the SDF1/CXCR4 signaling pathway. These findings have important therapeutic implications for Chinese medicine-assisted cell-based therapy strategies.

Suppression of the SDF‑1/CXCR4/β‑catenin axis contributes to bladder cancer cell growth inhibition invitro and invivo.

Previous studies have found that the activation of stromal cell‑derived factor‑1 (SDF‑1)/CXC chemokine receptor‑4 (CXCR4)/β‑catenin signaling is associated with biological malignant potential in cancers. However, its function has been rarely reported in the progression of bladder cancer (BCa). The aim of the present study was to investigate the association of SDF‑1/CXCR4 signaling and β‑catenin in regards to BCa cell proliferation, colony formation, migration and invasion. The methods used were MTS, colony formation, and Transwell migration and invasion assays which were performed in SW780 cells following treatment with the CXCR4 antagonist AMD3465, SDF‑1, the β‑catenin antagonist FH535, AMD3465+SDF‑1 or FH535+SDF‑1. The mRNA and protein levels were assayed by RT‑qPCR and western blotting, respectively. The effect of AMD3465 on SW780 cell xenograft growth invivo was evaluated using a nude mouse model. According to our results, human BCa SW780 cells were identified as having high expression of CXCR4 and β‑catenin. Subsequently, we found that both CXCR4 and β‑catenin antagonists could significantly inhibit the proliferation, colony formation, migration and invasion of SW780 cells. Notably, SDF‑1 could reverse the inhibitory effects of AMD3465 and FH535 on proliferation, colony formation, migration and invasion in SW780 cells. In AMD3465‑treated SW780 cells, the expression of c‑myc was significantly upregulated, and E‑cadherin was downregulated in the presence of SDF‑1. Furthermore, the tumor volume and average weight in the AMD3465‑treated group were evidently less than these parameters in the control group, indicating that AMD3465 can inhibit SW780 cell growth invivo. In conclusion, targeting the SDF‑1/CXCR4/β‑catenin axis may be a potential therapeutic target for suppressing BCa progression.

LncRNA PRNCR1 regulates CXCR4 expression to affect osteogenic differentiation and contribute to osteolysis after hip replacement

BackgroundOsteogenic differentiation plays an essential role in the pathogenesis of osteolysis, which is a complication of hip orthroplasty. The roles of lncRNA PRNCR1 in osteogenic differentiation and osteolysis were dissected in this study. MethodsThe expression of PRNCR1, miR-211-5p and C-X-C chemokine receptor-4 (CXCR4) protein in wear particles and mesenchymal stem cells (MSCs) were determined by qRT-PCR and Western blot, separately. The osteogenic differentiation degree of MSCs was assessed by ALP activity detection and ARS staining. Binding and interaction between RNA and protein were determined with RIP and RNA pull-down assay, respectively. Interaction between miR-211-5p and CXCR4 was examined by Dual luciferase reporter assay. ResultsPRNCR1 and CXCR4 were up-regulated in wear particles around prosthesis and in MSCs treated with PMMA, while miR-211-5p was down-regulated. Repression of PRNCR1 weakened the inhibitory effect of wear particles on osteogenic differentiation. PRNCR1 positively regulated CXCR4 through inhibiting miR-211-5p. Wear particles increased CXCR4 level through miR-211-5p to inhibit osteogenic differentiation of MSCs. Wear particles down-regulated miR-211-5p level through PRNCR1 to influence osteogenic differentiation of MSCs. ConclusionLncRNA PRNCR1 up-regulates CXCR4 through targeting miR-211-5p, which affects osteogenic differentiation and thus contributing to osteolysis after hip replacement.

CXCR4 and PD-1 Expression in Head and Neck Cancer with Perineural Spread.

Background Perineural spread (PNS) is a marker of aggressiveness and has been shown to occur in cranial nerves due to advanced mucosal and cutaneous head and neck cancer. Receptors CXC chemokine receptor 4 (CXCR4) and programmed cell death-1 (PD-1) have been shown to be overexpressed in a variety of cancers with PNS, with the inhibition of these pathways offering a potential future treatment. Methods Retrospective immunohistochemical staining for the CXCR4 and PD-1 receptors was performed on 28 head and neck specimens that demonstrated PNS from January 2017 to August 2017, at Royal Brisbane and Women's Hospital, Brisbane, Australia. Results CXCR4 staining was positive in 52 and 60% of the squamous cell carcinoma (SCC) and adenoid cystic carcinoma PNS specimens, respectively. Cutaneous SCC tumors with no PNS stained positively in 33%. No significant staining for PD-1 in peritumoral lymphocytes or tumor specimens was seen. Conclusion CXCR4 is overexpressed in advanced skin cancer and head and neck tumors that demonstrated PNS to large cranial nerves. Overall, these results provide strong support for using CXCR4 as a biomarker and further investigation of immunotherapeutic agents that could inhibit tumor progression via targeting CXCR4 expression.

Combined Evaluation of Expression of CXCR4 and Nrf2 as Prognostic Factor for Patients with Gastric Carcinoma.

CXC Chemokine Receptor 4 (CXCR4) and NFE-related factor 2 (Nrf2) have been observed implicated with cell malignant behavior of human cancers. In this study, we detected their expression in gastric carcinoma (GC) tissue specimens and related the result with clinicopathological data and patient survival. 120 GC and compared normal tissue specimens were processed to analyse the expression of CXCR4 and Nrf2. We found that the expression of CXCR4 and Nrf2 was dramatically increased in GC tissues when compared to the distant non-cancer tissues (P<0.05). CXCR4 overexpression was associated with the depth of invasion (P= 0.006), Histological grade (P=0.018), TNMstage (P= 0.021), lymph node metastasis (P < 0.001) and distant metastasis (P=0.026), whereas overexpression of Nrf2 protein was significantly associated with tumor size (P=0.045), Histological grade (P=0.026), TNMstage (P= 0.020), lymph node metastases (P < 0.001) and distant metastasis (P=0.008). Furthermore, we observed a significant co-expression of CXCR4 and Nrf2 expression in GC specimens. In the survival part, we found that GC patients with CXCR4+ and Nrf2+ had worse outcomes. The significant prognostic indicators are age, tumor size, histological grade, TNMstage, CXCR4, Nrf2, and coexpression of CXCR4 and Nrf2 in GC patients. Multivariate analysis showed that TNMstage and CXCR4+/Nrf2+ expression were risk factors. Above all we come to the conclusion that the expression of CXCR4 might partly be regulated by the level of Nrf2 and both positive expressions suggest poor prognosis of GC patients.

Hypoxia‑induced expression of CXCR4 favors trophoblast cell migration and invasion via the activation of HIF‑1α.

The placenta initially develops in a low-oxygen environment up to week 8–10 of gestation, and a low oxygen level is a critical factor in the regulation of trophoblast migration and invasion. CXC chemokine receptor 4 (CXCR4) is transcriptionally activated by hypoxia in cancer cells. However, whether CXCR4 is involved in hypoxia-inducible factor (HIF)-1α-dependent trophoblastic migration and invasion in a physiologically hypoxic environment (3% O2) remains to be fully elucidated and requires further investigation. In the present study, the expression of CXCR4 in first-trimester villi was investigated, as was the response of the trophoblast to hypoxia, and the role of CXCR4 and HIF-1α in trophoblast migration and invasion. CXCR4 was significantly elevated in the first-trimester villi compared with normal full-term placentas. In vitro, the expression of CXCR4 at the mRNA and protein levels was increased in JEG3 cells exposed to 3% O2 in a time-dependent manner, and the migratory and invasive abilities of the JEG3 cells were upregulated. In addition, CXCR4 knockdown by transfection with CXCR4-specific small interfering (si)RNA decreased the migration and invasion of JEG3 cells exposed to 3% O2. Furthermore, synthetic siRNA specific for HIF-1α significantly suppressed the expression of CXCR4 in JEG3 cells exposed to 3% O2, whereas pcDNA-HIF-1α significantly increased the expression of CXCR4. These results indicated that the hypoxia-induced expression of CXCR4 promoted trophoblast cell migration and invasion via the activation of HIF-1α, which is crucial during placentation.

Targeting CXCR4–CXCL12 Axis for Visualizing, Predicting, and Inhibiting Breast Cancer Metastasis with Theranostic AMD3100–Ag2S Quantum Dot Probe

AbstractBreast cancer metastasis remains the primary cause of death and efforts to predict and reduce metastatic risk are particularly appealing. CXC chemokine receptor 4 (CXCR4) is reported as a specific metastasis due to its chemotactic homing to CXCL12. Herein, conjugation of a CXCR4 antagonist, AMD3100, to a fluorescent silver sulfide quantum dot (Ag2S) core (QD‐AMD) allows accurate detection of CXCR4 expression in tumor. Particularly, the probe precisely distinguishes highly metastatic breast cancer cells from those of lower metastatic ability. Longitudinal in vivo imaging predicts at early stages that the high CXCR4 expressing orthotopic 4T1 tumor would subsequently metastasize to lungs 14 d after tumor inoculation, while no metastasis forms from the low CXCR4 expressing MCF‐7 tumor. Correlative measurements find that the CXCL12 levels in lung increase with tumor progression. Perturbations of either CXCR4 on tumor cells by QD‐AMD or CXCL12 in the lungs by antibody successfully inhibit cancer metastasis. Intravenous injection of QD‐AMD in primary 4T1 tumor model effectively reduces lung metastasis. More importantly, due to the intrinsic photothermal effect, the metastatic spread is more thoroughly abrogated along with substantial shrinkage of primary tumor. Altogether, the probe is promising to detect, predict, and inhibit the metastatic spread of breast tumor.

Adenosine A(2A) receptor activation reverses hypoxia‑induced rat pulmonary artery smooth muscle cell proliferation via cyclic AMP‑mediated inhibition of the SDF1‑CXC4 signaling pathway.

The occurrence and the subsequent development of pulmonary arterial hypertension (PAH) involve complicated mechanisms. Of these, the proliferation of pulmonary artery smooth muscle cells (PASMCs) has been indicated to be closely associated with its progression. Therefore, therapeutic methods targeting PASMCs to inhibit proliferation is an effective method for alleviating PAH. The present study was designed to determine the role of the adenosine A(2A) receptor (A2A receptor) in hypoxia‑induced rat PASMC (RPASMC) proliferation. Primary RPASMCs were isolated from the pulmonary artery of adult male SD rats, cultured and used for the following experiments. The mRNA level and protein expression of CXCR4 were measured by reverse transcription‑quantitative polymerase chain reaction and western blot analysis, respectively. The cell proliferation of RPASMCs was measured using a cell proliferation assay kit. In the present study, it was demonstrated that the proliferation of RPASMCs was partially mediated by activation of the stromal cell‑derived factor 1 (SDF1)‑CXC chemokine receptor 4 (CXCR4) axis under hypoxic conditions. In addition, SDF1‑α alone upregulated the mRNA and protein expression levels of CXCR4, and stimulated the proliferation of RPASMCs. The protein expression of CXCR4 and the cell proliferation were markedly inhibited by application of A2A receptor agonist CGS21680 or cyclic adenosine monophosphate(cAMP) under hypoxic conditions or treatment with SDF1‑α and was reversed by the A2A receptor antagonist SCH58261 or 8‑bromoadenosine‑3',5'‑cyclic monophosphorothioate. These results demonstrated that the inhibition of SDF1‑CXC4 signaling by the activation of A2A receptor and subsequent increase in the level of cAMP may be a potential method to ameliorate PAH.

Dual expression of CXCR4 and IL-35 enhances the therapeutic effects of BMSCs on TNBS-induced colitis in rats through expansion of Tregs and suppression of Th17 cells

Bone marrow-derived mesenchymal stem cells (BMSCs) hold great promise for the treatment of inflammatory bowel disease owing to their immunosuppressive property and tissue healing potential. The balance between regulatory T cells (Tregs) and T helper (Th)17 cells plays a crucial role in BMSC-mediated immunosuppression. Interleukin (IL)-35 is a newly identified anti-inflammatory cytokine required for the expansion of Tregs and suppression of Th17 cell differentiation. IL-35 can amplify the immunosuppressive property of BMSCs when overexpressed in these cells. However, the reparative capability of BMSCs in vivo is limited, partly due to the poor homing efficiency of BMSCs to inflamed colons. Up-regulation of CXC chemokine receptor 4 (CXCR4) expression in BMSCs may affect the directional homing of implanted BMSCs via stromal-derived factor-1. In this study, by lentivirus-mediated introduction of CXCR4 and IL-35 genes to modify rat BMSCs, we observed enhanced migration and strengthened immunomodulatory activities of the genetically engineering BMSCs. These results suggest that modification of BMSCs by dual expression of CXCR4 and IL-35 may provide an effective therapeutic strategy for inflammatory bowel disease.

Leptin receptor q223r polymorphism influences neutrophil mobilization after Clostridium difficile infection.

Clostridium difficile is the leading cause of nosocomial infections in the U.S. Clinical disease outcomes after C. difficile infection (CDI) are dependent on intensity of host inflammatory responses. Specifically, peak peripheral white blood cell (WBC) count >20×109/L is an indicator of adverse outcomes in CDI patients, and is associated with higher 30-day mortality. We show that homozygosity for a common single nucleotide polymorphism (Q to R mutation in leptin receptor that is present in up to 50% of people), significantly increases the risk of having peak peripheral WBC count >20×109/L (odds ratio=4.7; p = 0.0024) in CDI patients. In a murine model of CDI, we demonstrate that mice homozygous for the same SNP (RR mice) have more blood and tissue leukocytes (specifically neutrophils), exaggerated tissue inflammation and higher mortality as compared to control mice, despite similar pathogen burden. Further, we show that neutrophilia in RR mice is mediated by gut microbiota-directed expression of CXC chemokine receptor 2 (CXCR2) which promotes the release of neutrophils from bone marrow reservoir. Overall these studies provide novel mechanistic insights into the role of human genetic polymorphisms and gut microbiota in regulating the fundamental biological process of CDI-induced neutrophilia.

Deferoxamine promotes mesenchymal stem cell homing in noise-induced injured cochlea through PI3K/AKT pathway.

Over 5% of the world's population suffers from disabling hearing loss. Stem cell homing in target tissue is an important aspect of cell-based therapy, which its augmentation increases cell therapy efficiency. Deferoxamine (DFO) can induce the Akt activation, and phosphorylation status of AKT (p-AKT) upregulates CXC chemokine receptor-4 (CXCR4) expression. We examined whether DFO can enhance mesenchymal stem cells (MSCs) homing in noise-induced damaged cochlea by PI3K/AKT dependent mechanism. Mesenchymal stem cells were treated with DFO. AKT, p-AKT protein and hypoxia inducible factor 1- α (HIF-1α) and CXCR4 gene and protein expression was evaluated by RT- PCR and Western blot analysis. For in vivo assay, rats were assigned to control, sham, noise exposure groups without any treatment or receiving normal, DFO-treated and DFO +LY294002 (The PI3K inhibitor)-treated MSCs. Following chronic exposure to 115 dB white noise, MSCs were injected into the rat cochlea through the round window. Number of Hoechst- labelled cells was determined in the endolymph after 24hours. Deferoxamine increased P-AKT, HIF-1α and CXCR4 expression in MSCs compared to non-treated cells. DFO pre-conditioning significantly increased the homing ability of MSCs into injured ear compared to normal MSCs. These effects of DFO were blocked by LY294002. Pre-conditioning of MSCs by DFO before transplantation can improve stem cell homing in the damaged cochlea through PI3K/AKT pathway activation.