CCR5 Inhibitors Research Articles

Low-Dose Maraviroc, an Antiretroviral Drug, Attenuates the Infiltration of T Cells into the Central Nervous System and Protects the Nigrostriatum in Hemiparkinsonian Monkeys.

Parkinson's disease (PD) is the most common neurodegenerative movement disorder in humans. Despite intense investigation, no effective therapy is available to stop the progression of this disease. It is becoming clear that both innate and adaptive immune responses are active in PD. Accordingly, we have reported a marked increase in RANTES and eotaxin, chemokines that are involved in T cell trafficking, in vivo in the substantia nigra (SN) and the serum of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-intoxicated hemiparkinsonian monkeys. Because RANTES and eotaxin share a common receptor, CCR5, we examined the efficacy of maraviroc, an inhibitor of CCR5 and a Food and Drug Administration-approved drug against HIV infection, in hemiparkinsonian rhesus monkeys. First, we found glial limitans injury, loss of GFAP immunostaining, and infiltration of T cells across the endothelial monolayer in SN of hemiparkinsonian monkeys. However, oral administration of a low dose of maraviroc protected glia limitans partially, maintained the integrity of endothelial monolayer, reduced the infiltration of T cells, attenuated neuroinflammation, and decreased α-synucleinopathy in the SN. Accordingly, maraviroc treatment also protected both the nigrostriatal axis and neurotransmitters and improved motor functions in hemiparkinsonian monkeys. These results suggest that low-dose maraviroc and other CCR5 antagonists may be helpful for PD patients.

Treatment of Central Nervous System Manifestations of HIV in the Current Era

Treatment of neurological, neurocognitive, and neuropsychiatric impairment in the setting of human immunodeficiency virus (HIV) infection remains a complex problem, given several possible mechanisms of pathogenesis. The etiology must be determined based on clinical judgment and objective evidence, including cerebrospinal fluid (CSF) data from lumbar puncture and neuroimaging information from magnetic resonance imaging, when available and indicated. Other neuroinfectious etiologies must be ruled out, including central nervous system (CNS) opportunistic infections. HIV replication in the CNS (including CSF escape) should be evaluated for and excluded. If CSF HIV is detected, we recommend a treatment switch to antiretrovirals (ARVs) targeted to address any CSF HIV resistance mutations identified, or empiric treatment intensification using ARVs with high CNS penetration. If CSF HIV is not detected, treatment intensification with CCR5 inhibitors may be considered as an adjunct to reduce neuroinflammation. Finally, the current ARV regimen must be examined for possible neurotoxicity. Efavirenz has been well-recognized for its neuropsychiatric adverse effects and potential for causing sleep disturbances. Similar concerns have recently been raised with integrase inhibitors, especially dolutegravir and raltegravir, although further studies are needed to determine the risks for clinically relevant neuropsychiatric side effects from these medications, given their overall high potency and proven success in treating systemic HIV.

Chinese‐German Cooperation Group Tumor Immunology: Another inspiring Meeting in Deidesheim

Chinese‐German Cooperation Group Tumor Immunology: Another inspiring Meeting in Deidesheim

Activity and structural analysis of GRL-117C: a novel small molecule CCR5 inhibitor active against R5-tropic HIV-1s

CCR5 is a member of the G-protein coupled receptor family that serves as an essential co-receptor for cellular entry of R5-tropic HIV-1, and is a validated target for therapeutics against HIV-1 infections. In the present study, we designed and synthesized a series of novel small CCR5 inhibitors and evaluated their antiviral activity. GRL-117C inhibited the replication of wild-type R5-HIV-1 with a sub-nanomolar IC50 value. These derivatives retained activity against vicriviroc-resistant HIV-1s, but did not show activity against maraviroc (MVC)-resistant HIV-1. Structural modeling indicated that the binding of compounds to CCR5 occurs in the hydrophobic cavity of CCR5 under the second extracellular loop, and amino acids critical for their binding were almost similar with those of MVC, which explains viral cross-resistance with MVC. On the other hand, one derivative, GRL-10018C, less potent against HIV-1, but more potent in inhibiting CC-chemokine binding, occupied the upper region of the binding cavity with its bis-THF moiety, presumably causing greater steric hindrance with CC-chemokines. Recent studies have shown additional unique features of certain CCR5 inhibitors such as immunomodulating properties and HIV-1 latency reversal properties, and thus, continuous efforts in developing new CCR5 inhibitors with unique binding profiles is necessary.

Vaginal rings with exposed cores for sustained delivery of the HIV CCR5 inhibitor 5P12-RANTES

Antiretroviral-releasing vaginal rings are at the forefront of ongoing efforts to develop microbicide-based strategies for prevention of heterosexual transmission of the human immunodeficiency virus (HIV). However, traditional ring designs are generally only useful for vaginal administration of relatively potent, lipophilic, and small molecular weight drug molecules that have sufficient permeability in the non-biodegradable silicone elastomer or thermoplastic polymers. Here, we report a novel, easy-to-manufacture ‘exposed-core’ vaginal ring that provides sustained release of the protein microbicide candidate 5P12-RANTES, an experimental chemokine analogue that potently blocks the HIV CCR5 coreceptor. In vitro release, mechanical, and stability testing demonstrated the utility and practicality of this novel ring design. In a sheep pharmacokinetic model, a ring containing two ¼-length excipient-modified silicone elastomer cores – each containing lyophilised 5P12-RANTES and exposed to the external environment by two large windows – provided sustained concentrations of 5P12-RANTES in vaginal fluid and vaginal tissue between 10 and 10,000 ng/g over 28days, at least 50 and up to 50,000 times the reported in vitro IC50 value.

Abstract A114: Omental fat in ovarian cancer induces metabolic and immune alterations

Abstract Epithelial ovarian cancer (EOC) is an immunogenic tumor entity, as evidenced by multiple correlative studies indicating the impact of intraepithelial tumor-infiltrating T lymphocyte (TIL) density on patient outcome. Immunotherapy trials have generated modest results so far and chemotherapy remains standard of care. In this study, we focus on EOC metastases invading the omentum. Our aim is to characterize their immune landscape with the goal of identifying specific targetable characteristics of these metastases, which are the most prevalent and relate to high morbidity.We used a cohort of 120 ovarian cancer specimens for histologic analysis, cytokine, or metabolic profiling. Furthermore, we developed an EOC tissue explant culture model and treated whole-tissue explants with drugs before assessing immune cell density, distribution, and activation status. Finally, we cultured macrophages isolated from patient-derived ascites to study their response to various treatments.Samples were classified into omental metastases and primary tumors (based on the presence of fat on histologic sections). We observed that omental metastases are characterized by an inflamed microenvironment orchestrated by macrophages and are infiltrated by high amounts of TILs with low expression of activation markers, and a skewed localization around fat patches. These TILs express high amounts of the tumor-supporting CCL5 chemokine. Macrophages storing fatty acids in the form of big vacuoles were found in these fatty tumors as well. Targeting macrophages using the CCR5 inhibitor maraviroc in whole tissue explants effectively restored T-cell distribution across the tissue and slightly affected macrophage polarization specifically in fat-containing tumors. Inhibiting fatty acid import in macrophages more dramatically affected the cytokine landscape, also specifically in fat-containing tumors, and established a Th1-supporting environment permeable to T-cell expansion and activation. In brief, omental metastases are characterized by: (a) a smoldering inflammatory reaction and high macrophage density, (b) increased T-cell accumulation around fatty areas away from cancer cells, and (c) T-cell exhaustion accompanied by CCL5 expression. Treatment of EOC explants revealed that macrophages infiltrating omental metastases can be repolarized in situ, leading to TIL expansion and activation. Citation Format: Meggy Suarez-Carmona, Nektarios A. Valous, Pornpimol Charoentong, Jakob N. Kather, Mareike Hampel, Bénédicte M.A. Lenoir, Dyke Ferber, Sarah Schott, Sabine Kess, Inka Zoernig, Dirk Jaeger, Niels Halama. Omental fat in ovarian cancer induces metabolic and immune alterations [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A114.

Pediatric Phase II Study of Maraviroc for Acute Graft Versus Host Disease Prophylaxis

Background CCR5 inhibition is a promising approach to prevent visceral acute GVHD in adults after allogeneic hematopoietic stem cell transplant (HSCT). Objective We performed a phase I/II study of maraviroc, an oral CCR5 inhibitor, to prevent visceral GVHD in children undergoing HSCT and have reported results of the phase I study previously. Methods We used our previously established dose (∼ 300 mg/m2) of maraviroc in the phase II study. Oral maraviroc was added to standard acute GVHD prophylaxis from day-3 twice daily for eligible patients until day+30 after HSCT. Trough levels of maraviroc were collected on day 0 +7, 14 and 21. Patients were observed until day+100 for acute GVHD. We assessed functional CCR5 blockade by our previously published pharmacodynamic assay. We explored mechanisms of resistance to maraviroc by comparing serum IL-15 levels, plasma CXCL9 and CXCL10 at day+30 between GVHD and no GVHD patients. CD38 expression on CD4+ T-cells measured by flow cytometry at day+30. Results Thirty-one patients were enrolled prospectively, 14 on the phase I and 17 on the phase II study. Phase II study Demographics are shown in Figure 1. Median maraviroc trough concentrations were therapeutic at > 100 ng/mL on day+7 and day+14 (Figure 2A). Functional CCR5 blockade was observed in all except one patient at day zero and day+14 (Figure 2B, 3A). Two patients developed grade 1 acute skin GVHD and were successfully treated with corticosteroids. Four patients developed gastrointestinal (GI) GVHD (Upper GI GVHD n=2, lower GI GVHD n=2). Two of these 4 patients with GI GVHD did not receive the planned 34 days of maraviroc. No adverse effects to maraviroc were observed. Seven patients discontinued maraviroc at a median of day+14 (range day+1- day+29) due to study rules regarding hepatotoxicity (n=5), renal function decline (n=1) and withdrawal from study (n=1). Phase I± Phase II study Incidence of GI GVHD in all 31 patients who received maraviroc was 19% (n=6) compared to 22% in historic controls (p=0.29). Four of the 6 GI GVHD patients did not complete maraviroc treatment. CD38 expression on CD4+ T-cells was elevated on day+30 in patients who developed GVHD compared to patients without GVHD (Figure 3B). We observed no difference in IL-15, CXCL10 and CXCL9 levels in patients with and without GVHD. Conclusion Maraviroc administration was feasible in children but was limited by elevated bilirubin levels and transaminases, unrelated to maraviroc. We achieved successful CCR5 blockade but also observed breakthrough of GVHD due to failure to administer maraviroc consistently. Peripheral blood activation of T-cell lymphocytes occurs in patients with imminent acute GVHD despite maraviroc prophylaxis, as might be expected since maraviroc regulates lymphocyte homing but does not suppress activation.

CCR5 Inhibitors and HIV-1 Infection.

CCR5 Inhibitors and HIV-1 Infection.

Comprehensive Analysis of Chemokines in Host Organs and Their Corresponding Receptors on Donor T-Cells in Xenogeneic Gvhd Model

Comprehensive Analysis of Chemokines in Host Organs and Their Corresponding Receptors on Donor T-Cells in Xenogeneic Gvhd Model

Marginal Effects of Systemic CCR5 Blockade with Maraviroc on Oral Simian Immunodeficiency Virus Transmission to Infant Macaques.

Current approaches do not eliminate all human immunodeficiency virus type 1 (HIV-1) maternal-to-infant transmissions (MTIT); new prevention paradigms might help avert new infections. We administered maraviroc (MVC) to rhesus macaques (RMs) to block CCR5-mediated entry, followed by repeated oral exposure of a CCR5-dependent clone of simian immunodeficiency virus (SIV) mac251 (SIVmac766). MVC significantly blocked the CCR5 coreceptor in peripheral blood mononuclear cells and tissue cells. All control animals and 60% of MVC-treated infant RMs became infected by the 6th challenge, with no significant difference between the number of exposures (P = 0.15). At the time of viral exposures, MVC plasma and tissue (including tonsil) concentrations were within the range seen in humans receiving MVC as a therapeutic. Both treated and control RMs were infected with only a single transmitted/founder variant, consistent with the dose of virus typical of HIV-1 infection. The uninfected RMs expressed the lowest levels of CCR5 on the CD4+ T cells. Ramp-up viremia was significantly delayed (P = 0.05) in the MVC-treated RMs, yet peak and postpeak viral loads were similar in treated and control RMs. In conclusion, in spite of apparent effective CCR5 blockade in infant RMs, MVC had a marginal impact on acquisition and only a minimal impact on the postinfection delay of viremia following oral SIV infection. Newly developed, more effective CCR5 blockers may have a more dramatic impact on oral SIV transmission than MVC.IMPORTANCE We have previously suggested that the very low levels of simian immunodeficiency virus (SIV) maternal-to-infant transmissions (MTIT) in African nonhuman primates that are natural hosts of SIVs are due to a low availability of target cells (CCR5+ CD4+ T cells) in the oral mucosa of the infants, rather than maternal and milk factors. To confirm this new MTIT paradigm, we performed a proof-of-concept study in which we therapeutically blocked CCR5 with maraviroc (MVC) and orally exposed MVC-treated and naive infant rhesus macaques to SIV. MVC had only a marginal effect on oral SIV transmission. However, the observation that the infant RMs that remained uninfected at the completion of the study, after 6 repeated viral challenges, had the lowest CCR5 expression on the CD4+ T cells prior to the MVC treatment appears to confirm our hypothesis, also suggesting that the partial effect of MVC is due to a limited efficacy of the drug. New, more effective CCR5 inhibitors may have a better effect in preventing SIV and HIV transmission.

Abstract CT124: A phase Ib/II study of BMS-813160, a CC chemokine receptor (CCR) 2/5 dual antagonist, in combination with chemotherapy or nivolumab in patients (pts) with advanced pancreatic or colorectal cancer

Abstract Background: During cancer progression, immunosuppressive cells, such as those of myeloid and lymphoid origin, are recruited to the tumor microenvironment (TME) through interactions between chemokines and chemokine receptors (CKRs). CCR2 and CCR5 are CKRs expressed on both myeloid and T-cell infiltrates in the TME and have been shown to mediate the migration of monocyte/myeloid-derived suppressor cells (MDSCs) and polymorphonuclear MDSCs (PMN-MDSCs), respectively, from bone marrow to the blood and TME. CCR5 can also recruit regulatory T cells to the TME, potentiate PMN-MDSC immunosuppressive function via arginase-1, and polarize tumor-associated macrophages into an immunosuppressive M2 phenotype. Engagement of CCR2 or CCR5 promotes an immunosuppressive environment and prevents antitumor immunity; this has been preclinically validated in multiple tumor types, including pancreatic and colorectal. Preliminary data also support the utility of combination with PD-(L)1 inhibition. Clinically, CCR2- and CCR5-selective antagonists have separately shown proof of mechanism in combination with chemotherapy in pts with pancreatic and colorectal cancers, respectively (1, 2). These encouraging studies support further investigation of CCR2/5 dual antagonism in providing greater benefit to pts than CCR2- or CCR5-selective inhibition when combined with chemotherapy. Here we describe the design of a phase 1b/2, nonrandomized, open-label study of BMS-813160 (small-molecule CCR2/5 dual antagonist) as monotherapy or in combination with chemotherapy or nivolumab in pts with advanced pancreatic or colorectal cancer (NCT03184870). Methods: Approximately 260 pts aged ≥ 18 years with an ECOG PS of ≤ 1, adequate marrow and organ function, and the ability to undergo pre- and on-treatment biopsies will be enrolled. Exclusion criteria include prior treatment with CCR2 and/or CCR5 inhibitors, requirement for corticosteroids/other immunosuppressive medications, CNS metastases, autoimmune diseases, and symptomatic interstitial lung disease. In part 1, pts will receive BMS-813160 monotherapy safety lead-in for 2 weeks followed by combination with chemotherapy (5-fluorouracil + leucovorin + irinotecan [colorectal cancer] or nab-paclitaxel + gemcitabine [pancreatic cancer]) or nivolumab. In part 2, pts will receive either the same regimens (without a monotherapy lead-in) or BMS-813160 monotherapy. Primary outcomes are safety, tolerability, objective response rate, median duration of response, and progression-free survival rate at 24 weeks. Secondary outcomes are pharmacokinetics and pharmacodynamics of BMS-813160 and immunogenicity of nivolumab.

Simultaneous blockade of IL-6 and CCL5 signaling for synergistic inhibition of triple-negative breast cancer growth and metastasis

BackgroundMetastatic triple-negative breast cancer (TNBC) is a heterogeneous and incurable disease. Numerous studies have been conducted to seek molecular targets to treat TNBC effectively, but chemotherapy is still the main choice for patients with TNBC. We have previously presented evidence of the important roles of interleukin-6 (IL-6) and chemokine (C-C motif) ligand 5 (CCL5) in TNBC tumor growth and metastasis. These experiments highlighted the importance of the crosstalk between cancer cells and stromal lymphatic endothelial cells (LECs) in tumor growth and metastasis.MethodsWe examined the viability and migration of MDA-MB-231-LN, SUM149, and SUM159 cells co-cultured with LECs when treated with maraviroc (CCR5 inhibitor) and tocilizumab (anti-IL-6 receptor antibody). To assess the anti-tumor effects of the combination of these two drugs in an athymic nude mouse model, MDA-MB-231-LN cells were implanted in the mammary fat pad and maraviroc (8 mg/kg, orally daily) and cMR16-1 (murine surrogate of the anti-IL-6R antibody, 10 mg/kg, IP, 3 days a week) were administrated for 5 weeks and effects on tumor growth and thoracic metastasis were measured.ResultsIn this study, we used maraviroc and tocilizumab to confirm that IL-6 and CCL5 signaling are key pathways promoting TNBC cell proliferation and migration. Further, in a xenograft mouse model, we showed that tumor growth was dramatically inhibited by cMR16-1, the mouse version of the anti-IL6R antibody. The combination of maraviroc and cMR16-1 caused significant reduction of TNBC tumor growth compared to the single agents. Significantly, the combination of maraviroc and cMR16-1 abrogated thoracic metastasis.ConclusionTaken together, these findings show that IL-6 and CCL5 signaling, which promote crosstalk between TNBC and lymphatic vessels, are key enhancers of TNBC tumor growth and metastasis. Furthermore, these results demonstrate that a drug combination inhibiting these pathways may be a promising therapy for TNBC patients.

Maraviroc Is Associated with Latent HIV-1 Reactivation through NF-κB Activation in Resting CD4+ T Cells from HIV-Infected Individuals on Suppressive Antiretroviral Therapy.

Maraviroc is a CCR5 antagonist used in the treatment of HIV-1 infection. We and others have suggested that maraviroc could reactivate latent HIV-1. To test the latency-reversing potential of maraviroc and the mechanisms involved, we performed a phase II, single-center, open-label study in which maraviroc was administered for 10 days to 20 HIV-1-infected individuals on suppressive antiretroviral therapy (EudraCT registration no. 2012-003215-66). All patients completed full maraviroc dosing and follow-up. The primary endpoint was to study whether maraviroc may reactivate HIV-1 latency, eliciting signaling pathways involved in the viral reactivation. An increase in HIV-1 transcription in resting CD4+ T cells, estimated by levels of HIV-1 unspliced RNA, was observed. Moreover, activation of the NF-κB transcription factor was observed in these cells. To elucidate the mechanism of NF-κB activation by maraviroc, we have evaluated in HeLa P4 C5 cells, which stably express CCR5, whether maraviroc could be acting as a partial CCR5 agonist, with no other mechanisms or pathways involved. Our results show that maraviroc can induce NF-κB activity and that NF-κB targets gene expression by CCR5 binding, since the use of TAK779, a CCR5 inhibitor, blocked NF-κB activation and functionality. Taking the results together, we show that maraviroc may have a role in the activation of latent virus transcription through the activation of NF-κB as a result of binding CCR5. Our results strongly support a novel use of maraviroc as a potential latency reversal agent in HIV-1-infected patients.IMPORTANCE HIV-1 persistence in a small pool of long-lived latently infected resting CD4+ T cells is a major barrier to viral eradication in HIV-1-infected patients on antiretroviral therapy. A potential strategy to cure HIV-1-infection is the use of latency-reversing agents to eliminate the reservoirs established in resting CD4+ T cells. As no drug has been shown to be completely effective so far, the search for new drugs and combinations remains a priority for HIV cure. We examined the ability of maraviroc, a CCR5 antagonist used as an antiretroviral drug, to activate latent HIV-1 in infected individuals on antiretroviral therapy. The study showed that maraviroc can activate NF-κB and, subsequently, induce latent HIV-1-transcription in resting CD4+ T cells from HIV-1-infected individuals on suppressive antiretroviral therapy. Additional interventions will be needed to eliminate latent HIV-1 infection. Our results suggest that maraviroc may be a new latency-reversing agent to interfere with HIV-1 persistence during antiretroviral therapy.

CCR5 Governs DNA Damage Repair and Breast Cancer Stem Cell Expansion.

The functional significance of the chemokine receptor CCR5 in human breast cancer epithelial cells is poorly understood. Here, we report that CCR5 expression in human breast cancer correlates with poor outcome. CCR5+ breast cancer epithelial cells formed mammospheres and initiated tumors with >60-fold greater efficiency in mice. Reintroduction of CCR5 expression into CCR5-negative breast cancer cells promoted tumor metastases and induced DNA repair gene expression and activity. CCR5 antagonists Maraviroc and Vicriviroc dramatically enhanced cell killing mediated by DNA-damaging chemotherapeutic agents. Single-cell analysis revealed CCR5 governs PI3K/Akt, ribosomal biogenesis, and cell survival signaling. As CCR5 augments DNA repair and is reexpressed selectively on cancerous, but not normal breast epithelial cells, CCR5 inhibitors may enhance the tumor-specific activities of DNA damage response-based treatments, allowing a dose reduction of standard chemotherapy and radiation.Significance: This study offers a preclinical rationale to reposition CCR5 inhibitors to improve the treatment of breast cancer, based on their ability to enhance the tumor-specific activities of DNA-damaging chemotherapies administered in that disease. Cancer Res; 78(7); 1657-71. ©2018 AACR.

Effects of treatment with Maraviroc a CCR5 inhibitor on a human hepatic stellate cell line.

After an acute liver damage, tissue regeneration repairs lesions with degradation of deposed fibrotic material, while mechanisms of tissue restoration are persistently activated following several repeated injuries, inducing deposition of extracellular matrix. (ECM). Factors responsible for ECM remodeling have been identified in a pathway involving a family of zinc-dependent enzyme matrix metalloproteinases (MMPs), together with tissue inhibitor of metalloproteinases (TIMPs). Recent experimental models suggested a role of CCR5 receptor in the genesis of liver fibrosis. Drawing from these background we decided to evaluate the effects of the treatment with the CCR5 inhibitor Maraviroc on LX-2, a human hepatic stellate cell line (HSC). Treatment with Maraviroc resulted in a block in S phase of LX-2 cells with increased expression levels of cyclin D1 and p21 while the expression of p53 was reduced. Treatment with Maraviroc was also able to block the accumulation of fibrillar collagens and extracellular matrix proteins (ECM), as demonstrated by the decrease of specific markers as Collagen type I, α-SMA, and TGF-β1. In addition we observed a down regulation of both metalloproteins (MMP-2, MMP-9), used for the degradation of the extracellular matrix and their inhibitors (TIMP-1, TIMP-2). The identification of a compound that may modulate the dynamic of liver fibrosis could be crucial in all chronic liver diseases. Maraviroc could play an important role because, in addition to its own anti-HIV activity, it could reduce the release of pro-inflammatory citokynes implicated in liver fibrogenesis.

Preventing HIV transmission through blockade of CCR5: rationale, progress and perspectives.

Of the two million people estimated to be newly infected with human immunodeficiency virus (HIV) every year, 95% live in poorer regions of the world where effective HIV treatment is not universally available. Strategies to reduce the spread of HIV infection, which predominantly occurs via sexual contact, are urgently required. In the absence of an effective vaccine, a number of approaches to prevent HIV infection have been developed. These include using potent anti-HIV drugs prophylactically, either through systemic administration or topical application to the mucosal tissues that HIV initially encounters during sexual transmission. Genetic deficiency of the chemokine receptor CCR5 provides individuals with a remarkable degree of protection from HIV acquisition. This is because CCR5 is the major coreceptor used by HIV to infect new target cells. Since CCR5 deficiency does not appear to carry any health disadvantages, targeting the receptor is a promising strategy for both therapy and prevention of HIV. In this review we first describe the advantages and limitations of the currently available strategies for HIV prevention, then we focus on strategies targeting CCR5, covering the progress that has been made in developing different classes of CCR5 inhibitors for prophylaxis, and the perspectives for their future development as new weapons in the global fight against HIV/AIDS.

CCR5/CCL5 axis interaction promotes migratory and invasiveness of pancreatic cancer cells

Pancreatic cancer (PC) is one of the deadliest cancers and remains a major challenge due to its invasive and metastatic nature. Increased levels of CCR5 and CCL5 have established indicators for disease status in various cancers, including PC. However, their role in invasion and metastasis of PC is not known. Here we conducted immunohistochemistry of PC tissues and found elevated epithelial staining for CCR5 and CCL5 in metastatic PC tissues compared to non-neoplastic. In vitro experiments, such as flow cytometry, immunofluorescence and western blotting with human PC cell lines (AsPc-1, BxPc-3 and MIA PaCa-2), showed higher expression levels of CCR5. The CCL5 activation of PC cells expressing CCR5 increased their invasive potential, while treatment with CCR5 inhibitor maraviroc inhibited the CCL5 activation. CCL5 induced proliferation of PC cells was mediated through F-actin polymerization, while there was marked reduction when the cells were treated with maraviroc. The direct interaction of CCR5 with CCL5 was verified using a calcium mobilization assay. Taken together, our results demonstrate that CCR5 and CCL5 are potential markers for metastatic PC cancer, and their interaction leads to the increased PC cell invasion. Thus, blocking CCR5/CCL5 axis might prove beneficial to prevent metastasis and provide a more therapeutic strategy to control PC progression.

O-GalNAcylation of RANTES Improves Its Properties as a Human Immunodeficiency Virus Type 1 Entry Inhibitor.

Many human proteins have the potential to be developed as therapeutic agents. However, side effects caused by direct administration of natural proteins have significantly slowed expansion of protein therapeutics into the clinic. Post-translational modifications (PTMs) can improve protein properties, but because of significant knowledge gaps, we are considerably limited in our ability to apply PTMs to generate better protein therapeutics. Here, we seek to fill the gaps by studying the PTMs of a small representative chemotactic cytokine, RANTES. RANTES can inhibit HIV-1 infection by competing with it for binding to receptor CCR5 and stimulating CCR5 endocytosis. Unfortunately, RANTES can induce strong signaling, leading to severe inflammatory side effects. We apply a chemical biology approach to explore the potential of post-translationally modified RANTES as safe inhibitors of HIV-1 infection. We synthesized and systematically tested a library of RANTES isoforms for their ability to inhibit inflammatory signaling and prevent HIV-1 infection of primary human cells. Through this research, we revealed that most of the glycosylated variants have decreased inflammation-associated properties and identified one particular glyco variant, a truncated RANTES containing a Galβ1-3GalNAc disaccharide α-linked to Ser4, which stands out as having the best overall properties: relatively high HIV-1 inhibition potency but also weak inflammatory properties. Moreover, our results provided a structural basis for the observed changes in the properties of RANTES. Taken together, this work highlights the potential importance of glycosylation as an alternative strategy for developing CCR5 inhibitors to treat HIV-1 infection and, more generally, for reducing or eliminating unwanted properties of therapeutic proteins.

Differential impact of the dual CCR2/CCR5 inhibitor cenicriviroc on migration of monocyte and lymphocyte subsets in acute liver injury.

A hallmark of acute hepatic injury is the recruitment of neutrophils, monocytes and lymphocytes, including natural killer (NK) or T cells, towards areas of inflammation. The recruitment of leukocytes from their reservoirs bone marrow or spleen into the liver is directed by chemokines such as CCL2 (for monocytes) and CCL5 (for lymphocytes). We herein elucidated the impact of chemokine receptor inhibition by the dual CCR2 and CCR5 inhibitor cenicriviroc (CVC) on the composition of myeloid and lymphoid immune cell populations in acute liver injury. CVC treatment effectively inhibited the migration of bone marrow monocytes and splenic lymphocytes (NK, CD4 T-cells) towards CCL2 or CCL5 in vitro. When liver injury was induced by an intraperitoneal injection of carbon tetrachloride (CCl4) in mice, followed by repetitive oral application of CVC, flow cytometric and unbiased t-SNE analysis of intrahepatic leukocytes demonstrated that dual CCR2/CCR5 inhibition in vivo significantly decreased numbers of monocyte derived macrophages in acutely injured livers. CVC also reduced numbers of Kupffer cells (KC) or monocyte derived macrophages with a KC-like phenotype, respectively, after injury. In contrast to the inhibitory effects in vitro, CVC had no impact on the composition of hepatic lymphoid cell populations in vivo. Effective inhibition of monocyte recruitment was associated with reduced inflammatory macrophage markers and moderately ameliorated hepatic necroses at 36h after CCl4. In conclusion, dual CCR2/CCR5 inhibition primarily translates into reduced monocyte recruitment in acute liver injury in vivo, suggesting that this strategy will be effective in reducing inflammatory macrophages in conditions of liver disease.

Computational Screening of CCR5 Inhibitors as Potential Entry Inhibitor Microbicides Using 3D-QSAR Studies, Docking and Molecular Dynamics Simulation

The chemokine receptor CCR5 acts as a co-receptor for HIV binding and it is considered as an important target by CCR5 antagonists. Entry inhibitor based microbicides gain much importance nowadays as these drugs act at an early stage of HIV lifecycle and thus hinder the viral replication process in humans. The present study intends to identify a CCR5 antagonist which could be developed as a microbicide using computational approaches. The pharmacophore modeling and 3D QSAR studies was used to screen CCR5 antagonists with enhanced antagonist activity. The docking studies ranked the compounds according to their binding affinity and molecular dynamics simulation validated the stability of the enzymeligand complex. A five point pharmacophore hypothesis HHPRR (2 hydrophobic; 1 positively ionisable; 2 aromatic ring) was generated. A statistically significant 3D QSAR model with 3 PLS factors was gen- erated for common pharmacophore hypothesis HHPRR.3 with good correlation coefficient value (R2=0.7483). The docking studies revealed that molecular interaction of CCR5 antagonists having good binding affinity are better than the microbicides taken for this study. The QSAR maps revealed the regions as a combined effect of hydrogen bond donors, hydrogen bond acceptors and hydrophobic groups which denoted the substitution of groups indicating the favorable and unfavorable regions for antagonist activity of hydroxypiperidine derivatives. The docking analysis and molecular dynamics simulation screened and validated CCR5 antagonists. The present study was successful in identifying a CCR5 antagonist which could be developed as a microbicide.