Biology subjects

Halfon, P.

Publications and source records attributed to Halfon, P..

7 recordsLinked to original sources

bioRxiv2023

Targeting PPT1 with ezurpimtrostat sensitives liver tumor to immunotherapy by switching cold into hot microenvironments

BackgroundPalmitoyl-protein thioesterase-1 (PPT1) is an exciting druggable target for inhibiting autophagy in cancer. MethodsIn this study, we aimed to evaluate the effects of ezurpimtrostat-targeting PPT1 in combination with an anti-PD-1 antibody in liver cancer using a transgenic immunocompetent mouse model. ResultsHerein, we revealed that inhibition of PPT1 using ezurpimtrostat, a safe anticancer drug in humans, decreased the liver tumor burden by inducing the penetration of lymphocytes within tumors when combined with anti-programmed death-1 (PD-1). Inhibition of PPT1 potentiates the effects of anti-PD-1 immunotherapy by increasing the expression of major histocompatibility complex (MHC)-I at the surface of liver cancer cells and modulates immunity through recolonization and activation of cytotoxic CD8+ lymphocytes. ConclusionsEzurpimtrostat turns cold into hot tumors and, thus, constitutes a powerful strategy to improve T cell-mediated immunotherapies in liver cancer. Summary boxWe reported that inhibiting palmitoyl-protein thioesterase-1 enzyme (PPT1) enhances the antitumor activity of anti-programmed death-1 (PD-1) in liver cancer in preclinical models. This study provides the rational for this combination in cancer clinical trials. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=143 SRC="FIGDIR/small/524541v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@1f44bf3org.highwire.dtl.DTLVardef@1a66ca8org.highwire.dtl.DTLVardef@127a51corg.highwire.dtl.DTLVardef@1c8f2af_HPS_FORMAT_FIGEXP M_FIG C_FIG Ezurpimtrostat activities in cancerThe absence of immune effectors especially cytotoxic cells in the microenvironment of cold tumor is associated with a lack of response to ICI. This condition is mainly due to an increase in the autophagy process responsible for the sequestration and destruction of an antigen-presenting molecule, MHC-I. The inhibition of PPT1 using ezurpimtrostat treatment led to (1) the inhibition of PPT1 and consequently the autophagy process, (2) the increase of MHC-I surface expression, and (3) the recruitment and the activation of CD8+ T cells at tumor site leading to (4) the improvement of CD8+ T cell cytotoxic activity. Thus, ezurpimtrostat-treated tumors become eligible for anti-PD-1 immunotherapy as the combination of both led to decreased macronodules, micronodules, and tumor growth.

cancer biology↗

bioRxiv2022

Vγ9Vδ2 T cells are potent inhibitors of SARS-CoV-2 replication and exert effector phenotypes in COVID-19 patients

V{gamma}9V{delta}2 T cells play a key role in the innate immune response to viral infections, including SARS-CoV-1 and 2, and are activated through butyrophilin (BTN)-3A. Here, the objectives were to: 1) characterize the effects of SARS-CoV-2 infection on the number, phenotype, and activation of V{gamma}9V{delta}2 T cells in infected patients, and 2) assess the effects of in vitro SARS-CoV-2 infection on the expression of BTN3A and its impact on the activation and response of V{gamma}9V{delta}2 T cells to an anti-BTN3A antibody. Blood V{gamma}9V{delta}2 T cells decreased in clinically mild SARS-CoV-2 infections compared to healthy volunteers (HV). This decrease was maintained up to 28 days and in the recovery period. Terminally differentiated V{gamma}9V{delta}2 T cells tend to be enriched on the day of diagnosis, 28 days after and during the recovery period compared to HV. Furthermore, these cells showed cytotoxic and inflammatory activities as shown by TNF, IFN{gamma} and CD107a/b increase following anti-BTN3A activation. Moreover, BTN3A upregulation and V{gamma}9V{delta}2 T cell infiltration were observed in a lung biopsy from a fatal SARS-CoV-2 infection, as compared to HV. In vitro, SARS-CoV-2 infection significantly increased BTN3A expression in macrophages and lung cell lines. The activation via BTN3A enhanced the anti-SARS-CoV-2 V{gamma}9V{delta}2 T cells cytotoxicity and IFN-{gamma} and TNF in SARS-CoV-2 infected patient. Increasing concentrations of anti-BTN3A were accompanied by an inhibition of viral replication. Altogether, these data suggest that V{gamma}9V{delta}2 T cells are important in the immune response against SARS-CoV-2 infection and that activation by an anti-BTN3A antibody may enhance their response. KEY POINTSO_LISARS-CoV-2 mediates upregulation of the key receptor of V{gamma}9V{delta}2 T cells BTN3A on lung tissues and cell lines as well as monocytes C_LIO_LIDuring SARS-CoV-2 infection, V{gamma}9V{delta}2 are differentiated and efficiently degranulate and secrete cytokines upon activation with BTN3A mAb C_LI

immunology↗

bioRxiv2021

First description of two immune escape indian B.1.1.420 and B.1.617.1 SARS-CoV2 variants in France

Following the outbreak of the SARS-CoV2 virus worldwide in 2019, the rapid widespread overtime of variants suggests today an undergoing positive selection of variants which could potentially provide advantageous genetic property of the virus. Numerous variants have already been described across different countries including N501Y, E484K or L452R mutations on gene coding to spike protein. Most recently, 2 new Indian variants with N440K and E484Q and L452R mutations associated with impaired antibody response and immune reactions were identified in India. The potential consequences of emerging variants are increased transmissibility, increased pathogenicity and the ability to escape natural or vaccine-induced immunity. We described for the first time in France both variants: the N440K immune escape variant within a new strain detected in France in a couple of patients who did not have any history of travel abroad and the new E484Q and L452R Indian variant from a patient travelling from Indian to Marseille to embark on a ship as a crew member. Such study of the circulating viral strains and their variants within the increasing number of infected people worldwide will provide further insights into the viral dissemination. Hence, real time close monitoring variant could help the scientific community to prevent fast-spreading and raise alarms towards potentially harmful variants.

molecular biology↗

bioRxiv2020

GNS561, a new autophagy inhibitor active against cancer stem cells in hepatocellular carcinoma and hepatic metastasis from colorectal cancer

Patients with advanced hepatocellular carcinoma (HCC) or metastatic colorectal cancer (mCRC) have a very poor prognosis due to the lack of efficient treatments. As observed in several other tumors, the effectiveness of treatments is mainly hampered by the presence of a highly tumorigenic sub-population of cancer cells called cancer stem cells (CSCs). Indeed, CSCs are resistant to chemotherapy and radiotherapy and have the ability to regenerate the tumor bulk. Hence, innovative drugs that are efficient against both bulk tumor cells and CSCs would likely improve cancer treatment. In this study, we demonstrated that GNS561, a new autophagy inhibitor that induces lysosomal cell death, showed significant activity against not only the whole tumor population but also a sub-population displaying CSC features (high ALDH activity and tumorsphere formation ability) in HCC and in liver mCRC cell lines. These results were confirmed in vivo in HCC from a DEN-induced cirrhotic rat model in which GNS561 decreased tumor growth and reduced the frequency of CSCs (CD90+CD45-). Accordingly, GNS561, which was in a global phase 1b clinical trial in liver cancers that was recently successful, offers great promise for cancer therapy by exterminating both the tumor bulk and the CSC sub-population.

cancer biology↗

bioRxiv2020

GNS561 exhibits potent in vitro antiviral activity against SARS-CoV-2 through autophagy inhibition

Since December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2/2019-nCoV) has spread quickly worldwide, with more than 29 million cases and 920,000 deaths. Interestingly, coronaviruses were found to subvert and hijack the autophagic process to allow their viral replication. One of the spotlights had been focused on the autophagy inhibitors as a target mechanism effective in the inhibition of SARS-CoV-2 infection. Consequently, chloroquine (CQ) and hydroxychloroquine (HCQ), a derivative of CQ, was suggested as the first potentially be therapeutic strategies as they are known to be autophagy inhibitors. Then, they were used as therapeutics in SARS-CoV-2 infection along with remdesivir, for which the FDA approved emergency use authorization. Here, we investigated the antiviral activity and associated mechanism of GNS561, a small basic lipophilic molecule inhibitor of late-stage autophagy, against SARS-CoV-2. Our data indicated that GNS561 showed the highest antiviral effect for two SARS-CoV-2 strains compared to CQ and remdesivir. Focusing on the autophagy mechanism, we showed that GNS561, located in LAMP2-positive lysosomes, together with SARS-CoV-2, blocked autophagy by increasing the size of LC3-II spots and the accumulation of autophagic vacuoles in the cytoplasm with the presence of multilamellar bodies characteristic of a complexed autophagy. Finally, our study revealed that the combination of GNS561 and remdesivir was associated with a strong synergistic antiviral effect against SARS-CoV-2. Overall, our study highlights GNS561 as a powerful drug in SARS-CoV-2 infection and supports that the hypothesis that autophagy inhibitors could be an alternative strategy for SARS-CoV-2 infection.

pathology↗

bioRxiv2020

GNS561, a clinical-stage PPT1 inhibitor, has powerful antitumor activity against hepatocellular carcinoma via modulation of lysosomal functions

Background & AimsHepatocellular carcinoma (HCC) is the most frequent primary liver cancer. Autophagy inhibitors have been extensively studied in cancer but, to date, none has reached efficacy in clinical trials. Approach & ResultsTo explore the antitumor effects of GNS561, a new autophagy inhibitor, we first achieved in vitro assays using various human cancer cell lines. Having demonstrated that GNS561 displayed high liver tropism using mass spectrometry imaging, the potency of GNS561 on tumor was evaluated in vivo in two HCC models (human orthotopic patient-derived xenograft mouse model and diethylnitrosanime-induced cirrhotic immunocompetent rat model). Oral administration of GNS561 was well tolerated and decreased tumor growth in these two models. GNS561 mechanism of action was assessed in an HCC cell line, HepG2. We showed that due to its lysosomotropic properties, GNS561 could reach and inhibited its enzyme target, palmitoyl-protein thioesterase 1, resulting in lysosomal unbound Zn2+ accumulation, impairment of cathepsin activity, blockage of autophagic flux, altered location of mTOR, lysosomal membrane permeabilization, caspase activation and cell death. ConclusionsGNS561, currently tested in a global Phase 1b/2a clinical trial against primary liver cancer, represents a promising new drug candidate and a hopeful therapeutic strategy in cancer treatment. With an estimated 782,000 deaths in 2018, hepatocellular carcinoma (HCC) stands as the most common primary liver cancer and constitutes the fourth leading cause of cancer-related death worldwide (1). The rising incidence of HCC, the high worldwide mortality rate, and limited therapeutic options at advanced stages, make HCC a significant unmet medical need. Autophagy-related lysosomal cell death, either alone or in connection with several other cell death pathways, has been recognized as a major target for cancer therapy (2). Dysregulated autophagic-lysosomal activity and mTOR signaling were shown to allow cancer cells to become resistant to the cellular stress induced by chemotherapy and targeted therapy (3). Recently, several lysosome-specific inhibitors were shown to target palmitoyl-protein thioesterase 1 (PPT1), resulting in the modulation of protein palmitoylation and autophagy, and antitumor activity in melanoma and colon cancer models (4, 5). Chloroquine (CQ) and hydroxychloroquine (HCQ) have been used for more than 50 years to prevent and treat malarial infections and autoimmune diseases. Based on the lysosomotropic properties and the capacity for autophagy inhibition, these molecules have been proposed as active drugs in cancer (6-9). Over 40 clinical trials have been reported to evaluate the activity of both CQ or HCQ as single agent or in combination with chemotherapy in several tumor types (6-8. However, the required drug concentrations to inhibit autophagy were not achieved in humans, leading to inconsistent results in cancer clinical trials (5, 10). This prompted research to identify novel compounds with potent inhibitory properties against autophagy for cancer therapy. We previously reported that GNS561 was efficient in intrahepatic cholangiocarcinoma (iCCA) by inhibiting late-stage autophagy (11). In this study, we investigated the mechanism of action of GNS561. We identified lysosomal PPT1 as a target of GNS561. Exposure to GNS561 induced lysosomal accumulation of unbound zinc ion (Zn2+), inhibition of PPT1 and cathepsin activity, blockage of autophagic flux and mTOR displacement. Interestingly, these effects resulted in lysosomal membrane permeabilization (LMP) and caspase activation that led to cancer cell death. This mechanism was associated with dose-dependent inhibition of cancer cell proliferation and tumor growth inhibition in two HCC in vivo models. These data establish PPT1 and lysosomes as major targets for cancer cells and led to the development of a clinical program investigating the effects of GNS561 in patients with advanced HCC.

cancer biology↗

bioRxiv2020

Monocytes and macrophages, targets of SARS-CoV-2: the clue for Covid-19 immunoparalysis

To date, the Covid-19 pandemic affected more than 18 million individuals and caused more than 690, 000 deaths. Its clinical expression is pleiomorphic and severity is related to age and comorbidities such as diabetes and hypertension. The pathophysiology of the disease relies on aberrant activation of immune system and lymphopenia that has been recognized as a prognosis marker. We wondered if the myeloid compartment was affected in Covid-19 and if monocytes and macrophages could be infected by SARS-CoV-2. We show here that SARS-CoV-2 efficiently infects monocytes and macrophages without any cytopathic effect. Infection was associated with the secretion of immunoregulatory cytokines (IL-6, IL-10, TGF-{beta}) and the induction of a macrophagic specific transcriptional program characterized by the upregulation of M2-type molecules. In addition, we found that in vitro macrophage polarization did not account for the permissivity to SARS-CoV-2, since M1-and M2-type macrophages were similarly infected. Finally, in a cohort of 76 Covid-19 patients ranging from mild to severe clinical expression, all circulating monocyte subsets were decreased, likely related to massive emigration into tissues. Monocytes from Covid-19 patients exhibited decreased expression of HLA-DR and increased expression of CD163, irrespective of the clinical status. Hence, SARS-CoV-2 drives circulating monocytes and macrophages inducing immunoparalysis of the host for the benefit of Covid-19 disease progression.

immunology↗