Noncyclam tetraamines inhibit CXC chemokine receptor type 4 and target glioma-initiating cells

The three stereoisomers of the noncyclam compound 1 (1(R,R), 1(S,S), and the meso form 1(S,R)) and their corresponding tetrahydrochlorides 11 were prepared from (S)- and (R)-2-methylpiperidine. We have evaluated their inhibitory activity on the CXC chemokine receptor type 4 (CXCR4), toxicity properties, and assessment of their effect on glioma initiating cells (GICs) in comparison with the prototype compound AMD3100. The IC(50) values determined on human recombinant (CHO) cells showed very similar inhibitory activities albeit a lower K(B) for AMD3100, with the 1(R,R) isomer being second in potency. All the compounds showed low cardiac toxicity but, contrary to AMD3100, gave maximum nonlethal doses of around 2.0 mg/kg. The CXCR4 inhibitors had an effect on the state of differentiation of GICs, decreasing the percentage of CD44+ cells in glioblastoma multiform neurospheres in vitro. Moreover, these CXCR4 inhibitors blocked the capacity of cells to initiate orthotopic tumors in immunocompromised mice.     

Anti-HIV activity and resistance profile of the CXC chemokine receptor 4 antagonist POL3026

We have studied the mechanism of action of Arg(*)-Arg-Nal(2)-Cys(1x)-Tyr-Gln-Lys-(d-Pro)-Pro-Tyr-Arg-Cit-Cys(1x)-Arg-Gly-(d-Pro)(*) (POL3026), a novel specific beta-hairpin mimetic CXC chemokine receptor (CXCR)4 antagonist. POL3026 specifically blocked the binding of anti-CXCR4 monoclonal antibody 12G5 and the intracellular Ca(2+) signal induced by CXC chemokine ligand 12. POL3026 consistently blocked the replication of human immunodeficiency virus (HIV), including a wide panel of X4 and dualtropic strains and subtypes in several culture models, with 50% effective concentrations (EC(50)) at the subnanomolar range, making POL3026 the most potent CXCR4 antagonist described to date. However, 1-[[4-(1,4,8,11-tetrazacyclotetradec-1-ylmethyl)phenyl]methyl]-1,4,8,11-tetrazacyclotetradecane (AMD3100)-resistant and stromal cell-derived factor-1alpha-resistant HIV-1 strains were cross-resistant to POL3026. Time of addition experiments and a multiparametric evaluation of HIV envelope function in the presence of test compounds confirmed the activity of POL3026 at an early step of virus replication: interaction with the coreceptor. Generation of HIV-1 resistance to POL3026 led to the selection of viruses 12- and 25-fold less sensitive and with mutations in gp120, including the V3 loop region. However, POL3026 prevented the emergence of CXCR4-using variants from an R5 HIV-1 strain that may occur in the presence of anti-HIV agents targeting CC chemokine receptor 5.     

Nuclear magnetic resonance studies of CXC chemokine receptor 4 allosteric peptide agonists in solution

Abstract: CXC chemokine receptor 4 (CXCR4) is an important pharmacological target due to its involvement in HIV‐1 pathogenesis and cancer metastasis. Two recently discovered allosteric agonists that bind and activate CXCR4, the ASLW and RSVM peptides, were analyzed using solution nuclear magnetic resonance spectroscopy. Both peptides assumed an extended backbone conformation with several well‐defined local motifs in the regions from residues 5 to 8 and 9 to 12. The local structures in the region of residues 5–8 were different for agonists studied here and natural ligands. The local structure in the region 9–12 was adopted by the entire ensemble of the ASLW peptide structures and by the subset of conformations for the RSVM peptide. The same turn was found in full‐length stromal derived factor (SDF)‐1 and in the small family of the SDF‐1 N‐terminal 17‐mer. Similar examples in literature suggest the relevance of nascent structures in peptides to their biologically relevant conformations. The significance of found local structures and implications for further drug design are discussed.     

Topotecan inhibits cancer cell migration by down-regulation of chemokine CC motif receptor 7 and matrix metalloproteinases

Aim： The aim of this study was to investigate the effect of topotecan （TPT） on cancer cell migration. Methods： Growth inhibition of TPT was analyzed by MTT assay, and cancer cell migration was measured by transwell double chamber assay. To verify the effect of TPT on the chemokine receptors CXCR4 and CCR7, quantitative PCR, semiquantitative PCR and Western blot analysis were performed. The secretion of MMP-2 and MMP-9 was detected by enzymelinked immunosorbent assay （ELISA） and gelatin zymography. To evaluate possible contributions of CCR7 to MMP secre- tion, the overexpression vectors pcDNA3.1^＋-CCR7 and CCR7 siRNA were transiently transfected into MDA-MB-435 cells. Results： TPT inhibited cancer cell migration in a dose-dependent manner. Additionally, TPT significantly decreased the expression of CCR7 in both MDA-MB-435 and MDA-MB-231 cells and moderately reduced the expression of CXCR4 in MDA-MB-435 cells. The secretion of MMPs （MMP-2, MMP-9） was also inhibited by TPT. Overexpression of CCR7 increased the secretion of MMP-2/9 and cancer cell migration, whereas knockdown of CCR7 reduced active MMP-2/9 production and migration of MDA-MB-435 cells. Conclusion： TPT inhibited cancer cell migration by down-regulation of CCR7 and MMPs （MMP-2 and MMP-9）.     

Structure-activity relationship study of a CXC chemokine receptor type 4 antagonist, FC131, using a series of alkene dipeptide isosteres

A structure-activity relationship study on a highly potent CXC chemokine receptor type 4 (CXCR4) antagonist, FC131 [cyclo(-d-Tyr(1)-Arg(2)-Arg(3)-Nal(4)-Gly(5)-)], was carried out using a series of alkene isosteres of the d-Tyr(1)-l/d-Arg(2) dipeptide to investigate the binding mode of FC131 and its derivatives with CXCR4. The structure-activity relationships of isostere-containing FC131 analogues were similar to those of the parent FC131 and its derivatives, suggesting that a trans-conformer of the d-Tyr(1)-Arg(2) peptide bond is the dominant contributor to the bioactive conformations of FC131. Although NMR analysis demonstrated that the two conformations of the peptidomimetic containing the d-Tyr(1)-d-Arg(2) isostere are possible, binding-mode prediction indicated that the orientations of the alkene motif within d-Tyr(1)-MeArg(2) peptidomimetics depend on the chirality of Arg(2) and the β-methyl group of the isostere unit, which makes the dominant contribution for binding to the receptor. The most potent FC122 [cyclo(-d-Tyr(1)-d-MeArg(2)-Arg(3)-Nal(4)-Gly(5)-)] bound with CXCR4 by a binding mode different from that of FC131.     

Comparison of the potential multiple binding modes of bicyclam, monocylam, and noncyclam small-molecule CXC chemokine receptor 4 inhibitors

CXC chemokine receptor (CXCR)4 is an HIV coreceptor and a chemokine receptor that plays an important role in several physiological and pathological processes, including hematopoiesis, leukocyte homing and trafficking, metastasis, and angiogenesis. This receptor belongs to the class A family of G protein-coupled receptors and is a validated target for the development of a new class of antiretroviral therapeutics. This study compares the interactions of three structurally diverse small-molecule CXCR4 inhibitors with the receptor and is the first report of the molecular interactions of the nonmacrocyclic CXCR4 inhibitor (S)-N'-(1H-benzimidazol-2-ylmethyl)-N'-(5,6,7,8-tetrahydroquinolin-8-yl)butene-1,4-diamine (AMD11070). Fourteen CXCR4 single-site mutants representing amino acid residues that span the entire putative ligand binding pocket were used in this study. These mutants were used in binding studies to examine how each single-site mutation affected the ability of the inhibitors to compete with (125)I-stromal-derived factor-1alpha binding. Our data suggest that these CXCR4 inhibitors bind to overlapping but not identical amino acid residues in the transmembrane regions of the receptor. In addition, our results identified amino acid residues that are involved in unique interactions with two of the CXCR4 inhibitors studied. These data suggest an extended binding pocket in the transmembrane regions close to the second extracellular loop of the receptor. Based on site-directed mutagenesis and molecular modeling, several potential binding modes were proposed for each inhibitor. These mechanistic studies might prove to be useful for the development of future generations of CXCR4 inhibitors with improved clinical pharmacology and safety profiles.     

Antimetastatic effect of prodigiosin through inhibition of tumor invasion

Prodigiosin, a bacterial metabolite, was reported to have immunosuppressive and anticancer activities. In this study, we investigated novel functions of prodigiosin about anti-metastasis and anti-invasion. Prodigiosin dose-dependently inhibited 95-D cells' migration and invasion according to wound healing assay and the Transwell assay. The inhibitive effect could reach about 50% when cells were treated with 5 microM prodigiosin for 12 h. In animal experiment, intraperitoneal administration of 5 mg kg(-1) prodigiosin decreased the number of metastatic nodules by 53% and elevated the survival rate of mice about one-fold comparing with control group. Results of cell aggregation and adhesion assay showed that prodigiosin could promote cell aggregation and simultaneously inhibit cell from adhering to extracellular matrix (ECM). In addition, prodigiosin suppressed RhoA gene expression, hence, decreased protein level of RhoA in 95-D cells, according to RT-PCR assay and Western blot assay. Gel zymogram assay revealed that prodigiosin could suppress the activity of matrix metalloproteinase-2 (MMP-2). These results demonstrate that prodigiosin effectively inhibit tumor metastasis in vitro and in vivo. The action mechanisms of prodigiosin are associated with the promotion of cell aggregation and the inhibition of various steps in cell invasive process, which include the inhibition of cell adhesion and mobility in a RhoA-dependent way and the suppression of MMP-2 ability.     

Glycyrrhizin prevents of lipopolysaccharide/D-galactosamine-induced liver injury through down-regulation of matrix metalloproteinase-9 in mice

Glycyrrhizin, a biological active compound isolated from the liquorice root, has been used as a treatment for chronic hepatitis. We have examined the involvement of matrix metalloproteinase (MMP)9 in the development of lipopolysaccharide (LPS) and D-galactosamine (GalN)-induced liver injury in mice. We also investigated the effect of glycyrrhizin on expression of MMP-9 in this model. Levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) increased after LPS/ GalN treatment. Expression of MMP-9 mRNA and protein was markedly up-regulated in liver tissues 6-8 h after LPS/GalN treatment. Pretreatment with glycyrrhizin (50 mg kg(-1)) and the MMP inhibitor (5 mg kg(-1)) suppressed increases in serum levels of ALT and AST in mice treated with LPS/GalN. Furthermore, glycyrrhizin inhibited levels of both mRNA and protein for MMP-9. Immunohistochemical reaction for MMP-9 was observed in macrophages/monocytes infiltrated in the inflammatory area of liver injury. Glycyrrhizin reduced the infiltration of inflammatory cells and immunoreactive MMP- 9 in liver injury. The results indicated that MMP-9 played a role in the development of LPS/GalN- induced mouse liver injury, and suggested that an inhibition by glycyrrhizin of the acute liver injury may have been due to a down-regulation of MMP-9.     

Current drug design of anti-HIV agents through the inhibition of C-C chemokine receptor type 5

Human immunodeficiency virus (HIV) is the responsible causal agent of acquired immunodeficiency syndrome (AIDS), a condition in humans in which the immune system begins to fail, allowing the entry of opportunistic infections. HIV infection in humans is considered pandemic by the World Health Organization (WHO). HIV needs to use a protein as a co-receptor to enter its target cells. Several chemokine receptors can in principle act as viral co-receptors, but the chemokine (C-C motif) receptor 5 (CCR5) is likely the most physiologically important co-receptor during natural infection. For this reason the development of new CCR5 inhibitors like anti-HIV agents, constitutes a challenge for the scientific community. The present review will focus on the current state of the design of novel anti-HIV drugs, and how the existing computer aided-drug design methodologies, have been effective in the search of new anti-HIV agents. In addition, a QSAR model based on substructural descirptors is presented as a rapid, rational and promising alternative for the discovery of anti-HIV agents through the inhibition of the CCR5.     

趋化因子受体4和基质衍生因子1的表达与卵巢癌发生的相关性分析

目的分析趋化因子受体4(CXCR4)和基质衍生因子1(SDF-1)在不同卵巢组织中的表达,探究二者在卵巢癌的发生、发展及转移过程中的作用。方法选择我院收治的35例卵巢上皮癌患者、卵巢上皮性良性肿瘤的患者27例以及正常的卵巢组织患者32例,采用免疫组化法进行检测,分析卵巢组织中的CXCR4、SDF-1的蛋白表达情况和临床病理因素的相关性。结果 SDF-1、CXCR4在正常卵巢组织、卵巢良性肿瘤肿瘤和卵巢恶性肿瘤中分别表达阴性、低表达以及高表达(P<0.05);SDF-1、CXCR4蛋白表达与FIGO分期、组织学分化均无显著差别(P>0.05),而和淋巴结是否转移呈正相关(P<0.05),SDF-1表达情况与患者具有腹水呈正相关(P<0.05)。结论 SDF-1、CXCR4的蛋白表达和卵巢癌有着一定的相关性,其可能参与了卵巢癌的转移过程,但是与卵巢癌的组织学分化情况无关,同时SDF-1、CXCR4的蛋白表达情况可以作为卵巢的重要致病因子。     

急性脑梗死患者颈动脉斑块与血清CXC趋化因子16和高敏C反应蛋白的相关性

目的 研究急性脑梗死患者颈动脉斑块与血清CXC趋化因子16、高敏C反应蛋白的相关性.方法 选取120例急性脑梗死患者,根据颈动脉超声结果首先将患者分为无斑块组(24例)和有斑块组(96例),根据斑块性质进一步将有斑块组患者分为稳定斑块组(45例)和不稳定斑块组(51例).患者均于入院次日清晨空腹抽取静脉血,测定血清CXC趋化因子受体16和高敏C反应蛋白水平.结果 脑梗死患者有斑块组血清CXC趋化因子受体16及高敏C反应蛋白水平均高于无斑块组[分别为(2.5±1.0) μg/L比(1.7±0.8) μg/L,(5.3±2.4) mg/L比(3.7±1.9) mg/L,均P＜0.01].脑梗死患者不稳定斑块组血清CXC趋化因子受体16及高敏C反应蛋白水平高于稳定斑块组[分别为(3.0±1.0) μg/L比(2.0±0.7) μg/L,(6.0 ±2.4) mg/L比(4.3 ±2.0)mg/L,均P＜0.01].血清CXC趋化因子受体16的受试者工作特征(ROC)曲线下面积为0.798,P=0.000,95％置信区间为0.709 ～0.886;高敏C反应蛋白的ROC曲线下面积为0.703,P=0.001,95％置信区间为0.598 ～0.807,血清CXC趋化因子受体16的ROC曲线下面积大于高敏C反应蛋白的ROC曲线下面积.结论 血清CXC趋化因子受体16、高敏C反应蛋白可预测脑梗死患者颈动脉硬化及斑块的稳定性.     

CXC趋化因子受体4及基质细胞衍生因子1在宫颈癌组织中的表达及其与化疗药物敏感性之间的关系

目的研究CXC趋化因子受体4(CXCR4)及基质细胞衍生因子1(SDF)-1在宫颈癌组织中的表达情况,及其与宫颈癌常规化疗药物敏感性之间的关系。方法收集山西医科大学第一医院2017年6月至2018年6月手术切除的宫颈癌组织新鲜标本40例,采用MTT法检测原代培养宫颈癌细胞对顺铂、环磷酰胺、紫杉醇、5-氟尿嘧啶的体外药物敏感性,蛋白印迹法检测癌组织中CXCR4及SDF-1的表达情况,分析CXCR4及SDF-1的表达与药物敏感性之间的关系。结果不同宫颈癌细胞体外对化疗药物敏感性存在差异,紫杉醇,顺铂,5-氟尿嘧啶及环磷酰胺的平均抑制率分别为:65±11、52±10、32±12、19±7,差异有统计学意义(P<0.05);与癌旁组织相比,CXCR4及SDF-1在宫颈癌组织中的表达显著增高(P<0.05),CXCR4及SDF-1的表达与肿瘤的分化程度及临床分期有关(P<0.05)。CXCR4及SDF-1在紫杉醇耐药组中的表达显著高于敏感组(P<0.05),SDF-1在顺铂耐药组中的表达显著高于敏感组(P<0.05)。结论 MTT药敏实验对宫颈癌化疗药物的选择具有一定的参考价值,CXCR4及SDF-1在宫颈癌中表达上调,可能与紫杉醇及顺铂的耐药有关。     

Interleukin-10 mediates the protective effect of Linomide by reducing CXC chemokine production in endotoxin-induced liver injury

The immunomodulator Linomide has been shown to protect against septic liver injury by reducing hepatic accumulation of leukocytes although the detailed anti-inflammatory mechanisms remain elusive. This study examined the effect of Linomide on the production of CXC chemokines, including macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (KC) and interleukin-10 (IL-10) in lipopolysaccharide (LPS)/d-galactosamine (Gal)-induced liver injury in mice. It was found that pretreatment with 300 mg kg(-1) of Linomide markedly suppressed leukocyte recruitment, perfusion failure, and hepatocellular damage and apoptosis in the liver of endotoxemic mice. Administration of Linomide inhibited endotoxin-induced gene expression of MIP-2 and KC and significantly reduced the hepatic production of MIP-2 and KC by 63 and 80%, respectively. Moreover, it was found that Linomide increased the liver content of IL-10 by more than three-fold in endotoxemic mice. The protective effect of Linomide against endotoxin-induced inflammation and liver injury was abolished in IL-10-deficient mice, suggesting that the beneficial effect of Linomide is dependent on the function of IL-10. Taken together, these novel findings suggest that the protective effect of Linomide is mediated via local upregulation of IL-10, which in turn decreases the generation of CXC chemokines and pathological recruitment of leukocytes in the liver of endotoxemic mice.     

Dipyrimidine amines: a novel class of chemokine receptor type 4 antagonists with high specificity

The C-X-C chemokine receptor type 4 (CXCR4)/stromal cell derived factor-1 (SDF-1 or CXCL12) interaction and the resulting cell signaling cascade play a key role in metastasis and inflammation. On the basis of the previously published CXCR4 antagonist 5 (WZ811), a series of novel nonpeptidic anti-CXCR4 small molecules have been designed and synthesized to improve potency. Following a structure-activity profile around 5, more advanced compounds in the N,N'-(1, 4-phenylenebis(methylene)) dipyrimidin-2-amines series were discovered and shown to possess higher CXCR4 binding potential and specificity than 5. Compound 26 (508MCl) is the lead compound and exhibits subnanomolar potency in three in vitro assays including competitive binding, Matrigel invasion and Gα(i) cyclic adenosine monophosphate (cAMP) modulation signaling. Furthermore, compound 26 displays promising effects by interfering with CXCR4 function in three mouse models: paw inflammation, Matrigel plug angiogenesis, and uveal melanoma micrometastasis. These data demonstrate that dipyrimidine amines are unique CXCR4 antagonists with high potency and specificity.     

Functional reconstitution of the human chemokine receptor CXCR4 with Gi/Go-proteins in Sf9 insect cells

The chemokine stromal cell-derived factor-1alpha (SDF-1alpha) binds to the chemokine receptor CXCR4 that couples to pertussis toxin-sensitive G-proteins of the G(i)/G(o)-family. CXCR4 plays a role in the pathogenesis of autoimmune diseases, human immunodeficiency virus infection and various tumors, fetal development as well as endothelial progenitor and T-cell recruitment. To this end, most CXCR4 studies have focused on the cellular level. The aim of this study was to establish a reconstitution system for the human CXCR4 that allows for the analysis of receptor/G-protein coupling at the membrane level. We wished to study specifically constitutive CXCR4 activity and the G-protein-specificity of CXCR4. We co-expressed N- and C-terminally epitope-tagged human CXCR4 with various G(i)/G(o)-proteins and regulator of G-protein signaling (RGS)-proteins in Sf9 insect cells. Expression of CXCR4, G-proteins, and RGS-proteins was verified by immunoblotting. CXCR4 coupled more effectively to Galpha(i1) and Galpha(i2) than to Galpha(i3) and Galpha(o) and insect cell G-proteins as assessed by SDF-1alpha-stimulated high-affinity steady-state GTP hydrolysis. The RGS-proteins RGS4 and GAIP enhanced SDF-1alpha-stimulated GTP hydrolysis. SDF-1alpha stimulated [(35)S]guanosine 5'-[gamma-thio]triphosphate (GTPgammaS) binding to Galpha(i2). RGS4 did not enhance GTPgammaS binding. Na(+) salts of halides did not reduce basal GTPase activity. The bicyclam, 1-[[1,4,8,11-tetrazacyclotetradec-1-ylmethyl)phenyl]methyl]-1,4,8,11-tetrazacyclotetradecane (AMD3100), acted as CXCR4 antagonist but was devoid of inverse agonistic activity. Halides reduced the maximum SDF-1alpha-stimulated GTP hydrolysis in the order of efficacy I(-) > Br(-) > Cl(-). In addition, salts reduced the potency of SDF-1alpha at activating GTP hydrolysis. From our data, we conclude the following: (1) Sf9 cells are a suitable system for expression of functionally intact human CXCR4; (2) Human CXCR4 couples effectively to Galpha(i1) and Galpha(i2); (3) There is no evidence for constitutive activity of CXCR4; (4) RGS-proteins enhance agonist-stimulated GTP hydrolysis, showing that GTP hydrolysis becomes rate-limiting in the presence of SDF-1alpha; (5) By analogy to previous observations made for the beta(2)-adrenoceptor coupled to G(s), the inhibitory effects of halides on agonist-stimulated GTP hydrolysis may be due to increased GDP-affinity of G(i)-proteins, reducing the efficacy of CXCR4 at stimulating nucleotide exchange.