Assessment of protein biomarkers for preoperative differential diagnosis between benign and malignant ovarian tumors.

OBJECTIVE: To estimate the diagnostic value of tumor and immune related proteins in the discrimination between benign and malignant adnexal masses, and between different subgroups of tumors. METHODS: In this exploratory diagnostic study, 254 patients with an adnexal mass scheduled for surgery were consecutively enrolled at the University Hospitals Leuven (128 benign, 42 borderline, 22 stage I, 55 stage II-IV, and 7 secondary metastatic tumors). The quantification of 33 serum proteins was done preoperatively, using multiplex high throughput immunoassays (Luminex) and electrochemiluminescence immuno-assay (ECLIA). We calculated univariable areas under the Receiver Operating Characteristic Curves (AUCs). To discriminate malignant from benign tumors, multivariable ridge logistic regression with backward elimination was performed, using bootstrapping to validate the resulting AUCs. RESULTS: CA125 had the highest univariable AUC to discriminate malignant from benign tumors (0.85, 95% confidence interval 0.79-0.89). Combining CA125 with CA72.4 and HE4 increased the AUC to 0.87. For benign vs borderline tumors, CA125 had the highest univariable AUC (0.74). For borderline vs stage I malignancy, no proteins were promising. For stage I vs II-IV malignancy, CA125, HE4, CA72.4, CA15.3 and LAP had univariable AUCs ≥0.80. CONCLUSIONS: The results confirm the dominant role of CA125 for identifying malignancy, and suggest that other markers (HE4, CA72.4, CA15.3 and LAP) may help to distinguish between stage I and stage II-IV malignancies. However, further research is needed, also to investigate the added value over clinical and ultrasound predictors of malignancy, focusing on the differentiation between subtypes of malignancy.

Novel urea and bis-urea primaquine derivatives with hydroxyphenyl or halogenphenyl substituents: Synthesis and biological evaluation.

A series of novel compounds 3a-j and 6a-j with primaquine and hydroxyl or halogen substituted benzene moieties bridged by urea or bis-urea functionalities were designed, synthesized and evaluated for biological activity. The title compounds were prepared using benzotriazole as the synthon, through several synthetic steps. 3-[3,5-Bis(trifluoromethyl)phenyl]-1-{4-[(6-methoxyquinolin-8-yl)amino]pentyl}urea (3j) was the most active urea and 1-[({4-[(6-methoxyquinolin-8-yl)amino]pentyl}carbamoyl)amino]-3-[3-(trifluoromethyl)phenyl]urea (6h) the most active bis-urea derivative in antiproliferative screening in vitro against eight tested cancer cell lines. Urea derivatives 3a-g with hydroxy group or one halogen atom showed moderate antiproliferative effects against all the tested cell lines, but stronger activity against breast carcinoma MCF-7 cell line, while trifluoromethyl derivatives 3h-j showed antiproliferative effects against all the tested cell lines in low micromolar range. Finally, bis-ureas with hydroxy and fluoro substituents 6a-d showed extreme selectivity and chloro or bromo derivatives 6e-g high selectivity against MCF-7 cells (IC50 0.1-2.6 µM). p-Fluoro derivative 6d, namely 3-(4-fluorophenyl)-1-[({4-[(6-methoxyquinolin-8-yl)amino]pentyl}carbamoyl)amino]urea, is the most promising compound. Further biological experiments showed that 6d affected cell cycle and induced cell death of MCF-7 cell line. Due to its high activity against MCF-7 cell line (IC50 0.31 µM), extreme selectivity and full agreement with the Lipinski's and Gelovani's rules for prospective small molecular drugs, 6d may be considered as a lead compound in development of breast carcinoma drugs. Urea 3b and almost all bis-ureas showed high antioxidant activity in DPPH assay, but urea derivatives were more active in lipid peroxidation test. Only few compounds exhibited weak inhibition of soybean lipoxygenase. Compound 3j exhibited the strongest antimicrobial activity in susceptibility assay in vitro (MIC = 1.6-12.5 µg ml-1).

Azithromycin and the treatment of lymphocytic airway inflammation after lung transplantation.

Lymphocytic airway inflammation is a major risk factor for chronic lung allograft dysfunction, for which there is no established treatment. We investigated whether azithromycin could control lymphocytic airway inflammation and improve allograft function. Fifteen lung transplant recipients demonstrating acute allograft dysfunction due to isolated lymphocytic airway inflammation were prospectively treated with azithromycin for at least 6 months (NCT01109160). Spirometry (FVC, FEV1 , FEF25-75 , Tiffeneau index) and FeNO were assessed before and up to 12 months after initiation of azithromycin. Radiologic features, local inflammation assessed on airway biopsy (rejection score, IL-17(+) cells/mm(2) lamina propria) and broncho-alveolar lavage fluid (total and differential cell counts, chemokine and cytokine levels); as well as systemic C-reactive protein levels were compared between baseline and after 3 months of treatment. Airflow improved and FeNO decreased to baseline levels after 1 month of azithromycin and were sustained thereafter. After 3 months of treatment, radiologic abnormalities, submucosal cellular inflammation, lavage protein levels of IL-1ß, IL-8/CXCL-8, IP-10/CXCL-10, RANTES/CCL5, MIP1-α/CCL3, MIP-1ß/CCL4, Eotaxin, PDGF-BB, total cell count, neutrophils and eosinophils, as well as plasma C-reactive protein levels all significantly decreased compared to baseline (p < 0.05). Administration of azithromycin was associated with suppression of posttransplant lymphocytic airway inflammation and clinical improvement in lung allograft function.

Novel semicarbazides and ureas of primaquine with bulky aryl or hydroxyalkyl substituents: synthesis, cytostatic and antioxidative activity.

Novel primaquine semicarbazides 7a-l and ureas 9a-g with modified benzhydryl, trityl, phenyl or hydroxyalkyl substituents were prepared and evaluated for cytostatic and antioxidative activities. Two synthetic approaches for preparation of the title semicarbazides were applied, both having certain advantages. In the first approach, the products grew from the semicarbazide side and the primaquine residue entered the molecule the last. In the second approach, semicarbazide grew from the primaquine side. This method was more convenient for synthesis of a series of semicarbazides: various products could be obtained from the same precursor N-(4-((6-methoxyquinolin-8-yl)amino)pentyl)hydrazinecarbox-amide (10). Primaquine ureas 9a-f were prepared from primaquine benzotriazolide 8 and corresponding amines and urea 9g directly from primaquine and 4-chloro-3-(fluoromethyl)phenyl isocyanate. All primaquine semicarbazide derivatives showed either prominent cytostatic activity towards all the tested cell lines (benzhydryl or trityl derivatives 7a-e) or high selectivity towards MCF-7 cells (hydroxyalkyl derivatives 7h-l), with IC50 values in the low micromolar range. The highest selectivity exerted symmetric bisprimaquine derivative 7f, with an IC50 0.2 µM against MCF-7 cells and practically no activity against other seven tested cancer cell lines. Urea derivatives 9a-f were generally less active than their semicarbazide analogues, but still selective towards MCF-7 cells. Urea 9g with the similar structure to cytostatic drug sorafenib, was the most active urea derivative. Semicarbazides 7g and 10 showed the best antioxidative activity as measured by DPPH (64% at 20 min and 90% at 60 min), while urea derivatives 9a-g, especially 9d, and semicarbazides 7a-g with lipophilic substituents exerted better LP antioxidant activity. Both semicarbazides and ureas with methoxy or chloro benzhydryl substituents and high Clog P values showed significant LOX inhibition.

Evaluation of a panel of 28 biomarkers for the non-invasive diagnosis of endometriosis.

BACKGROUND: At present, the only way to conclusively diagnose endometriosis is laparoscopic inspection, preferably with histological confirmation. This contributes to the delay in the diagnosis of endometriosis which is 6-11 years. So far non-invasive diagnostic approaches such as ultrasound (US), MRI or blood tests do not have sufficient diagnostic power. Our aim was to develop and validate a non-invasive diagnostic test with a high sensitivity (80% or more) for symptomatic endometriosis patients, without US evidence of endometriosis, since this is the group most in need of a non-invasive test. METHODS: A total of 28 inflammatory and non-inflammatory plasma biomarkers were measured in 353 EDTA plasma samples collected at surgery from 121 controls without endometriosis at laparoscopy and from 232 women with endometriosis (minimal-mild n = 148; moderate-severe n = 84), including 175 women without preoperative US evidence of endometriosis. Surgery was done during menstrual (n = 83), follicular (n = 135) and luteal (n = 135) phases of the menstrual cycle. For analysis, the data were randomly divided into an independent training (n = 235) and a test (n = 118) data set. Statistical analysis was done using univariate and multivariate (logistic regression and least squares support vector machines (LS-SVM) approaches in training- and test data set separately to validate our findings. RESULTS: In the training set, two models of four biomarkers (Model 1: annexin V, VEGF, CA-125 and glycodelin; Model 2: annexin V, VEGF, CA-125 and sICAM-1) analysed in plasma, obtained during the menstrual phase, could predict US-negative endometriosis with a high sensitivity (81-90%) and an acceptable specificity (68-81%). The same two models predicted US-negative endometriosis in the independent validation test set with a high sensitivity (82%) and an acceptable specificity (63-75%). CONCLUSIONS: In plasma samples obtained during menstruation, multivariate analysis of four biomarkers (annexin V, VEGF, CA-125 and sICAM-1/or glycodelin) enabled the diagnosis of endometriosis undetectable by US with a sensitivity of 81-90% and a specificity of 63-81% in independent training- and test data set. The next step is to apply these models for preoperative prediction of endometriosis in an independent set of patients with infertility and/or pain without US evidence of endometriosis, scheduled for laparoscopy.

CXCL12-CXCR4 axis in angiogenesis, metastasis and stem cell mobilization.

Chemokines are key players in the attraction and activation of leukocytes and are thus implicated in the recruitment of immune cells at sites of infection and/or inflammation. They exert their action by binding to seven-transmembrane G protein-coupled receptors. The chemokine stromal cell-derived factor-1 (SDF-1)/CXCL12 represents the single natural ligand for the chemokine receptor CXCR4. CXCL12 possesses angiogenic properties and is involved in the outgrowth and metastasis of CXCR4-expressing tumors and in certain inflammatory autoimmune disorders, such as rheumatoid arthritis. CXCR4 expression on tumor cells is upregulated by hypoxia and angiogenic factors, such as vascular endothelial growth factor (VEGF). CXCR4 also acts as a co-receptor for entry of human immunodeficiency virus (HIV) in CD4(+) T cells. Finally, CXCL12/CXCR4 interactions were shown to play an important role in the migration of hematopoietic stem cells and their progenitors from, and their retention within, the bone marrow, a site characterized by high CXCL12 expression. As such, CXCR4 inhibitors may be utilized to inhibit HIV-1 infection, tumor growth and metastasis and to mobilize hematopoietic stem cells from the bone marrow in the circulation, where they can be collected for autologous stem cell transplantation. Here, we discuss the different aspects of CXCL12/CXCR4 biology as well as the development and anti-cancer/stem cell mobilizing activity of CXCR4 antagonists.

Carbohydrate-binding agents (CBAs) inhibit HIV-1 infection in human primary monocyte-derived macrophages (MDMs) and efficiently prevent MDM-directed viral capture and subsequent transmission to CD4+ T lymphocytes.

Carbohydrate-binding agents (CBAs) have been proposed as innovative anti-HIV compounds selectively targeting the glycans of the HIV-1 envelope glycoprotein gp120 and preventing DC-SIGN-directed HIV capture by dendritic cells (DCs) and transmission to CD4(+) T-lymphocytes. We now show that CBAs efficiently prevent R5 HIV-1 infection of human primary monocyte-derived macrophage (MDM) cell cultures in the nanomolar range. Both R5 and X4 HIV-1 strains were efficiently captured by the macrophage mannose-binding receptor (MMR) present on MDM. HIV-1 capture by MMR-expressing MDM was inhibited by soluble mannose-binding lectin and MMR antibody. Short pre-exposure of these HIV-1 strains to CBAs is able to prevent virus capture by MDM and subsequent syncytia formation in cocultures of the CBA-exposed HIV-1-captured MDM and uninfected CD4(+) T-lymphocytes. The potential of CBAs to impair MDM in their capacity to capture and to transmit HIV to T-lymphocytes might be an important property to be taken into consideration in the eventual choice to select microbicide candidate drugs for clinical investigation.

Restricted entry of R5 HIV Type 1 strains into eosinophilic cells.

A cell culture system previously developed by our laboratory demonstrated that T cell-tropic (CXCR4-using) but not macrophage-tropic (CCR5-using) HIV-1 strains productively infected eosinophilic cells. In the current study, an improved model was used to determine the level of this viral restriction by assessing viral entry and coreceptor usage. The model was improved by using AML14.3D10 cells that were engineered to express CCR3 in addition to the major HIV-1 coreceptors, CD4, CXCR4, and CCR5, thus making them more like primary eosinophils. A polymerase chain reaction (PCR) assay was used to detect viral entry. In the PCR assay, primers specific for early reverse transcription products were used to amplify minus strand viral DNA from HIV-1-infected AML14.3D10-CCR3 eosinophilic cells. Coreceptor blocking experiments, using the CXCR4 antagonist AMD3100, were performed to determine coreceptor usage by the CXCR4-using (X4) strain known to productively infect the cells. Virus production was measured by p24 immunoassay. As expected, viral DNA was detected in AML14.3D10-CCR3 cells infected with X4 HIV-1, and cell viability was decreased during maximal viral production. Conversely, viral DNA was not detected in eosinophilic cells exposed to a CCR5-using (R5) HIV-1 strain that is also capable of using CCR3, indicating that R5 HIV-1 is unable to enter eosinophilic cells despite the presence of the appropriate coreceptors. Infection of AML14.3D10-CCR3 cells by HTLV-III(B) was completely inhibited by AMD3100, indicating that X4 HIV-1 enters the AML14.3D10-CCR3 cell line by using the CXCR4 coreceptor exclusively. Since X4 strains predominate during the late stages of HIV-1 infection in many patients, when eosinophil numbers also tend to increase, the ability of these HIV-1 strains to infect eosinophilic cells has important implications for the involvement of eosinophils in the pathogenesis of AIDS.

X4 HIV-1 induces neuroblastoma cell death by interference with CXCL12/CXCR4 interaction.

Human neuroblastoma SK-N-SH cells strongly express CXC-chemokine receptor 4 (CXCR4), the principal coreceptor for X4 HIV-1 strains, and its natural ligand stromal cell-derived factor 1 (SDF-1, recently renamed CXCL12). We investigated the impact of CXCR4 blockade by the specific CXCR4 antagonist AMD3100 or by X4 HIV-1 virus particles on the growth and survival of neuroblastoma SK-N-SH cells. SK-N-SH cell proliferation was inhibited byAMD3100 and anti-CXCL12 neutralizing antibodies, but enhanced by exogenously added CXCL12. Upon prolongedexposure to AMD3100, SK-N-SH cell death occurred throughdeficit of survival-promoting and growth-stimulatory signals generated by endogenous CXCL12. In analogy with the observations made with the CXCR4 inhibitor AMD3100, the X4 HIV-1 strains IIIB and SF-2, but not the R5 strain BaL, caused a marked cytopathic effect and strongly effected SK-N-SH cell death after at least 10 days of incubation. However, no virus production could be detected in the HIV-1-inoculated SK-N-SH cell cultures. Exogenously added CXCL12 afforded partial protection against X4 HIV-1-induced cytopathicity in SK-N-SH cells. Our data indicate that the endogenous CXCL12/CXCR4 signaling axis is critical for neuroblastoma cell survival and proliferation. Long-term blockade of CXCR4 through physical contact with the X4 HIV-1 envelope can cause neuronal cell death. This mechanism may possibly play a role in X4 HIV-associated neurodegeneration.

[Role of chemokines in the HIV infection process]. / Rol van chemokinen in het HIV infectieproces.

In order to infect a target cell, the HIV envelope glycoprotein gp 120 has to interact with both the cellular receptor CD4 and an HIV-coreceptor, i.e. the CC or CXC chemokine receptor CCR5 or CXCR4. Both coreceptors were immediately recognized as novel targets for anti-HIV-therapy. Blocking these coreceptors would protect the cell from viral entry and would reduce the viral transmission and pathogenesis. Here we describe the purification and characterization of natural chemokine variants and compare their antiviral activity. In addition, the role of proteases for the processing of the CC chemokines RANTES, eotaxin, MDC and MIP-1 alpha and of the CXC chemokine SDF-1 are studied. The MIP-1 alpha-isoform LD78 beta, that was purified form natural sources, inhibited HIV-infection completely in CCR5-transfected cells, mononuclear leukocytes and purified monocytes at low (ng/ml) concentrations. This research will make it feasible to develop specific chemokine-analogs that block HIV-entry. Deciphering the processes that play a role during the complicated interactions between HIV-gp120 and the cellular membrane may lead to a more efficient treatment of HIV-infections.

Antiviral agents active against human herpesviruses HHV-6, HHV-7 and HHV-8.

A series of antiviral compounds were examined for their activity against human herpesvirus type 6 (HHV-6), type 7 (HHV-7) and type 8 (HHV-8). They were selected either because they are already approved for clinical use in the treatment of herpesvirus infections (acyclovir, valaciclovir, penciclovir, famciclovir, ganciclovir, brivudin, foscarnet and cidofovir) or have demonstrated marked activity against herpesviruses (lobucavir, H2G, A-5021, D/L-cyclohexenyl G and S2242). In view of their host cell specificity, different cells and assays had to be used for determining antiviral activity against these three viruses. The most potent compounds with the highest antiviral selectivity index were: (i) for HHV-6; foscarnet, S2242, A-5021 and cidofovir; (ii) for HHV-7; S2242, cidofovir and foscarnet; and (iii) for HHV-8; S2242, cidofovir and ganciclovir. As mycophenolic acid has been shown to enhance significantly the activity of acyclic guanosine analogues (such as acyclovir, penciclovir and ganciclovir) in vitro against HSV-1, HSV-2, VZV and HCMV, it would seem worth evaluating whether mycophenolic acid also potentiates the activity of these acyclic guanosine analogues against HHV-6, -7 and -8.

HIV-1 gp120 and chemokine activation of Pyk2 and mitogen-activated protein kinases in primary macrophages mediated by calcium-dependent, pertussis toxin-insensitive chemokine receptor signaling.

Human immunodeficiency virus type 1 (HIV-1) uses the chemokine receptors CCR5 and CXCR4 as coreceptors for entry. It was recently demonstrated that HIV-1 glycoprotein 120 (gp120) elevated calcium and activated several ionic signaling responses in primary human macrophages, which are important targets for HIV-1 in vivo. This study shows that chemokine receptor engagement by both CCR5-dependent (R5) and CXCR4-dependent (X4) gp120 led to rapid phosphorylation of the focal adhesion-related tyrosine kinase Pyk2 in macrophages. Pyk2 phosphorylation was also induced by macrophage inflammatory protein-1beta (MIP-1beta) and stromal cell-derived factor-1alpha, chemokine ligands for CCR5 and CXCR4. Activation was blocked by EGTA and by a potent blocker of calcium release-activated Ca++ (CRAC) channels, but was insensitive to pertussis toxin (PTX), implicating CRAC-mediated extracellular Ca++ influx but not Galpha(i) protein-dependent mechanisms. Coreceptor engagement by gp120 and chemokines also activated 2 members of the mitogen-activated protein kinase (MAPK) superfamily, c-Jun amino-terminal kinase/stress-activated protein kinase and p38 MAPK. Furthermore, gp120-stimulated macrophages secreted the chemokines monocyte chemotactic protein-1 and MIP-1beta in a manner that was dependent on MAPK activation. Thus, the gp120 signaling cascade in macrophages includes coreceptor binding, PTX-insensitive signal transduction, ionic signaling including Ca++ influx, and activation of Pyk2 and MAPK pathways, and leads to secretion of inflammatory mediators. HIV-1 Env signaling through these pathways may contribute to dysregulation of uninfected macrophage functions, new target cell recruitment, or modulation of macrophage infection.

Macrophage tropism of human immunodeficiency virus type 1 isolates from brain and lymphoid tissues predicts neurotropism independent of coreceptor specificity.

The viral determinants that underlie human immunodeficiency virus type 1 (HIV-1) neurotropism are unknown, due in part to limited studies on viruses isolated from brain. Previous studies suggest that brain-derived viruses are macrophage tropic (M-tropic) and principally use CCR5 for virus entry. To better understand HIV-1 neurotropism, we isolated primary viruses from autopsy brain, cerebral spinal fluid, blood, spleen, and lymph node samples from AIDS patients with dementia and HIV-1 encephalitis. Isolates were characterized to determine coreceptor usage and replication capacity in peripheral blood mononuclear cells (PBMC), monocyte-derived macrophages (MDM), and microglia. Env V1/V2 and V3 heteroduplex tracking assay and sequence analyses were performed to characterize distinct variants in viral quasispecies. Viruses isolated from brain, which consisted of variants that were distinct from those in lymphoid tissues, used CCR5 (R5), CXCR4 (X4), or both coreceptors (R5X4). Minor usage of CCR2b, CCR3, CCR8, and Apj was also observed. Primary brain and lymphoid isolates that replicated to high levels in MDM showed a similar capacity to replicate in microglia. Six of 11 R5 isolates that replicated efficiently in PBMC could not replicate in MDM or microglia due to a block in virus entry. CD4 overexpression in microglia transduced with retroviral vectors had no effect on the restricted replication of these virus strains. Furthermore, infection of transfected cells expressing different amounts of CD4 or CCR5 with M-tropic and non-M-tropic R5 isolates revealed a similar dependence on CD4 and CCR5 levels for entry, suggesting that the entry block was not due to low levels of either receptor. Studies using TAK-779 and AMD3100 showed that two highly M-tropic isolates entered microglia primarily via CXCR4. These results suggest that HIV-1 tropism for macrophages and microglia is restricted at the entry level by a mechanism independent of coreceptor specificity. These findings provide evidence that M-tropism rather than CCR5 usage predicts HIV-1 neurotropism.

Productive infection of primary macrophages with human herpesvirus 7.

Here we demonstrate replication of human herpesvirus 7 (HHV-7), a T-lymphotropic virus, in macrophages. Productive replication was lost after 2 weeks, but HHV-7 DNA was detected up to 1 month after infection. Thus, macrophages become infected by HHV-7 and might play an important role as a viral reservoir, as has been demonstrated for human immunodeficiency virus type 1.

CXCR4 is the primary receptor for feline immunodeficiency virus in astrocytes.

Feline astrocytes were productively infected with the Crandell feline kidney (CrFK) cell-adapted feline immunodeficiency virus (FIV) Petaluma strain in a primary culture. They expressed mRNA of CXCR4, and the FIV infection was blocked by stromal cell-derived factor 1alpha (SDF-1alpha), SDF-1beta, or the bicyclam AMD3100 in a dose-dependent manner. These observations suggest that, like FIV infection in CrFK cells and lymphocytes, the virus uses CXCR4 as a primary receptor for infecting astrocytes and this can be a possible natural model for AIDS dementia complex.

AMD3100, a potent and specific antagonist of the stromal cell-derived factor-1 chemokine receptor CXCR4, inhibits autoimmune joint inflammation in IFN-gamma receptor-deficient mice.

Autoimmune collagen-induced arthritis (CIA) in IFN-gammaR-deficient DBA/1 mice was shown to be reduced in severity by treatment with the bicyclam derivative AMD3100, a specific antagonist of the interaction between the chemokine stromal cell-derived factor-1 (SDF-1) and its receptor CXCR4. The beneficial effect of the CXCR4 antagonist was demonstrable when treatment was initiated between the time of immunization and appearance of the first symptoms. Treatment also reduced the delayed-type hypersensitivity response to the autoantigen, collagen type II. These observations are indicative of an action on a late event in the pathogenesis, such as chemokine-mediated attraction of leukocytes toward joint tissues. The notion of SDF-1 involvement was further supported by the observation that exogenous SDF-1 injected in periarthritic tissue elicited an inflammatory response that could be inhibited by AMD3100. The majority of leukocytes harvested from inflamed joints of mice with CIA were found to be Mac-1(+) and CXCR4(+), and AMD3100 was demonstrated to interfere specifically with chemotaxis and Ca(2+) mobilization induced in vitro by SDF-1 on Mac-1(+)/CXCR4(+) splenocytes. We conclude that SDF-1 plays a central role in the pathogenesis of murine CIA, by attracting Mac-1(+)/CXCR4(+) cells to the inflamed joints.

Inhibition of HIV infection by CXCR4 and CCR5 chemokine receptor antagonists.

The chemokine receptors CXCR4 and CCR5 are used as co-receptors by the T cell-tropic (X4) and macrophage-tropic (R5) HIV-1 strains, respectively, for entering their host cells. Viral entry can be inhibited by the natural ligands for CXCR4, the CXC chemokine SDF-1 and CCR5, the CC chemokines RANTES, MIP-1alpha and MIP-1beta. Several peptidic compounds, T22 (an 18-mer), T134 (a 14-mer), ALX40-4C (a 9-mer) and CGP 64222 (also a 9-mer), have been identified as CXCR4 antagonists and show anti-HIV activity. Also, the HIV-1 tat protein has been described as a 'natural' CXCR4 antagonist with anti-HIV-1 activity. The most potent and specific CXCR4 antagonists are the bicyclam derivatives, which also potently block X4 HIV replication. AMD3100 has proved to be a highly specific CXCR4 antagonist, which consistently blocks the outgrowth of all X4 HIV and dual-tropic (R5/X4) variants that use CXCR4 for entering the cells (cell lines, CXCR4-transfected cell lines, lymphocytes or monocytes/ macrophages). From the bicyclam analogues, AMD3100 was selected as the clinical drug candidate, which, after initial Phase I (safety) studies, has proceeded to Phase II (efficacy) trials. The first non-peptidic compound that interacts with CCR5, and not with CXCR4, is a quaternary ammonium derivative, called TAK-779, which also has potent but variable anti-HIV activity. We believe that HIV entry/fusion inhibitors will become important new antiviral agents to combat AIDS. However, like the current clinically approved agents, they will need to be used in combinations consisting of antivirals that target other aspects of the HIV replication cycle, such as reverse transcriptase and protease, to obtain optimum therapeutic effects.

Acyclic/carbocyclic guanosine analogues as anti-herpesvirus agents.

Several guanosine analogues, i.e. acyclovir (and its oral prodrug valaciclovir), penciclovir (in its oral prodrug form, famciclovir) and ganciclovir, are widely used for the treatment of herpesvirus [i.e. herpes simplex virus type 1 (HSV-1), and type 2 (HSV-2), varicella-zoster virus (VZV) and/or human cytomegalovirus (HCMV)] infections. In recent years, several new guanosine analogues have been developed, including the 3-membered cyclopropylmethyl and -methenyl derivatives (A-5021 and synguanol) and the 6-membered D- and L-cyclohexenyl derivatives. The activity of the acyclic/carbocyclic guanosine analogues has been determined against a wide spectrum of viruses, including the HSV-1, HSV-2, VZV, HCMV, and also human herpesviruses type 6 (HHV-6), type 7 (HHV-7) and type 8 (HHV-8), and hepatitis B virus (HBV). The new guanosine analogues (i.e. A-5021 and D- and L-cyclohexenyl G) were found to be particularly active against those viruses (HSV-1, HSV-2, VZV) that encode for a specific thymidine kinase (TK), suggesting that their antiviral activity (at least partially) depends on phosphorylation by the virus-induced TK. Marked antiviral activity was also noted with A-5021 against HHV-6 and with D- and L-cyclohexenyl G against HCMV and HBV. The antiviral activity of the acyclic/carbocyclic nucleoside analogues could be markedly potentiated by mycophenolic acid, a potent inhibitor of inosine 5'-monophosphate (IMP) dehydrogenase. The new carbocyclic guanosine analogues (i.e. A-5021 and D- and L-cyclohexenyl G) hold great promise, not only as antiviral agents for the treatment of herpesvirus infections, but also an antitumor agents for the combined gene therapy/chemotherapy of cancer, provided that (part of) the tumor cells have been transduced by the viral (HSV-1, VZV) TK gene.

No selection for CCR5 coreceptor usage during parenteral transmission of macrophagetropic syncytium-inducing human immunodeficiency virus type 1.

In two cases of parenteral transmission of human immunodeficiency virus type 1 (HIV-1) syncitium-inducing (SI) variants, we previously observed selection for macrophagetropic variants. Although infection of macrophages is generally mediated via CCR5, we found no selection for SI variants that could use CCR5 as coreceptor in addition to CXCR4, suggesting that features other than coreceptor usage account for the macrophagetropism of these transmitted SI HIV-1 variants.