Targeting Tumor Angiogenesis with the Selective VEGFR-3 Inhibitor EVT801 in Combination with Cancer Immunotherapy

The receptor tyrosine kinase VEGFR-3 plays a crucial role in cancer-induced angiogenesis and lymphangiogenesis, promoting tumor development and metastasis. Here, we report the novel VEGFR-3 inhibitor EVT801 that presents a more selective and less toxic profile than two major inhibitors of VEGFRs (i.e., sorafenib and pazopanib). As monotherapy, EVT801 showed a potent antitumor effect in VEGFR-3–positive tumors, and in tumors with VEGFR-3–positive microenvironments. EVT801 suppressed VEGF-C–induced human endothelial cell proliferation in vitro and tumor (lymph)angiogenesis in different tumor mouse models. In addition to reduced tumor growth, EVT801 decreased tumor hypoxia, favored sustained tumor blood vessel homogenization (i.e., leaving fewer and overall larger vessels), and reduced important immunosuppressive cytokines (CCL4, CCL5) and myeloid-derived suppressor cells (MDSC) in circulation. Furthermore, in carcinoma mouse models, the combination of EVT801 with immune checkpoint therapy (ICT) yielded superior outcomes to either single treatment. Moreover, tumor growth inhibition was inversely correlated with levels of CCL4, CCL5, and MDSCs after treatment with EVT801, either alone or combined with ICT. Taken together, EVT801 represents a promising anti(lymph)angiogenic drug for improving ICT response rates in patients with VEGFR-3 positive tumors.

Significance:

The VEGFR-3 inhibitor EVT801 demonstrates superior selectivity and toxicity profile than other VEGFR-3 tyrosine kinase inhibitors. EVT801 showed potent antitumor effects in VEGFR-3–positive tumors, and tumors with VEGFR-3–positive microenvironments through blood vessel homogenization, and reduction of tumor hypoxia and limited immunosuppression. EVT801 increases immune checkpoint inhibitors’ antitumor effects.

Abstract CT206: EVT801, a novel selective VEGFR-3 inhibitor targeting tumor angiogenesis, started enrollment for its phase I first-in-human study

Introduction: EVT801 is a highly selective, orally available VEGFR3 inhibitor that strongly inhibits angiogenesis without inducing hypoxia, considered one of the main causes of cancer-associated immunosuppression. EVT801 has shown compelling single agent efficacy in multiple in vivo models. In addition, combination of EVT801 and Immune Checkpoint Therapy (ICT) agents shows additive effects, and thus holds promise for combination treatment without induction of hypoxia-induced-immunosuppression. A phase I clinical trial is underway.

Methods: The phase I trial will consist of two sequential stages. During the first stage, EVT801 will be administered to patients with advanced solid tumors in a multiple ascending dose study using an accelerated 3+3 design (1 patient per dose until grade 2 toxicities are observed) in up to 48 patients in 8 dose levels. The primary objective is to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D). Stage 2 will focus on validation of this RP2D in two 6-patient cohorts diagnosed with soft tissue sarcoma or renal cell carcinoma. These patients will participate in intensive analyses involving several biomarkers to better understand the pharmacological activity of the drug. A potential third stage, consisting of a multiple ascending dose evaluation of the combination of EVT801 with immuno-oncology drugs, may be added to the ongoing trial, pending further technical discussions with physicians and regulators. In addition to conventional measures of safety, tolerability, efficacy, and pharmacokinetics, the phase I study will employ a rich suite of histological, immunological, and radiological biomarkers to provide early insights into the activity of EVT801.

Citation Format: Carlos Gomez roca, Philippe Cassier, Marie Mandron, Myriam Estrabaut, Nathalie Delesque-Touchard, Adam C. Smith, Amy Klawitter, Leesa Gentry, Pierre Fons, Michael R. Paillasse, Lise Davenne, Michael Fitzgerald, James Garner, Jean-Pierre Delord. EVT801, a novel selective VEGFR-3 inhibitor targeting tumor angiogenesis, started enrollment for its phase I first-in-human study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT206.

Abstract 3203: Cutting edge biomarkers strategy to provide early insights into activity of EVT-801, a novel selective VEGFR-3 inhibitor that targets tumor angiogenesis during the FIH clinical trial

Introduction: EVT801 is a highly selective small molecule inhibitor of VEGFR3 and acts by inhibiting lymphangiogenesis and tumor angiogenesis in and around the tumor. It has shown compelling activity in a wide range of cancer models and is well-tolerated in preclinical toxicology studies. A phase I study is underway and will focus primarily on understanding the safety, tolerability, and pharmacokinetics of EVT801 across a range of doses.

Methods: The first stage of the study is designed to determine the maximum tolerated dose (MTD) and recommended Phase II dose (RP2D) for EVT801, with a second stage aiming to confirm RP2D in selected cancer patient populations. Clinical samples from these patients will be used to explore preliminary signals of clinical efficacy and investigate the biological activity of the drug using several biomarkers. Efficacy biomarkers will include imaging approaches (DCE-MRI and CEUS) to characterize tumor vascularization, as well as analysis of protein and mRNA quantification in on-treatment biopsies vs pre-treatment biopsies. Moreover, the relationship between activity of EVT801 and expression of key markers at protein and mRNA level will be investigated to potentially establish biomarkers for patient stratification and selection. Lastly, target engagement and pharmacodynamics effects will be investigated by immuno-monitoring as well as assessment of a defined set of proteins as markers of inflammation and angiogenesis as identified in preclinical in vivo models. We expect that these analyses will help to better understand the effects of the drug in human subjects and may also help to select the most responsive patients and provide early signs of clinical efficacy.

Citation Format: Michael R. Paillasse, James Garner, Michael Fitzgerald, Lise Davenne, Pierre-Benoit Ancey, celine Poussereau-Pomie, Michael Esquerre, Gaelle Badet, Joel Tuyaret, Marie Mandron, Philippe Rochaix, Maha Ayyoub, Clara Maria Scarlata, Christine Ménétrier-Caux, Chrsitophe CAUX, Philippe Cassier, Jean-Pierre Delord, Carlos Gomez Roca, Pierre Fons. Cutting edge biomarkers strategy to provide early insights into activity of EVT-801, a novel selective VEGFR-3 inhibitor that targets tumor angiogenesis during the FIH clinical trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3203.

Disrupting Mitochondrial Electron Transfer Chain Complex I Decreases Immune Checkpoints in Murine and Human Acute Myeloid Leukemic Cells

Oxidative metabolism is crucial for leukemic stem cell (LSC) function and drug resistance in acute myeloid leukemia (AML). Mitochondrial metabolism also affects the immune system and therefore the anti-tumor response. The modulation of oxidative phosphorylation (OxPHOS) has emerged as a promising approach to improve the therapy outcome for AML patients. However, the effect of mitochondrial inhibitors on the immune compartment in the context of AML is yet to be explored. Immune checkpoints such as ectonucleotidase CD39 and programmed dead ligand 1 (PD-L1) have been reported to be expressed in AML and linked to chemo-resistance and a poor prognosis. In the present study, we first demonstrated that a novel selective electron transfer chain complex (ETC) I inhibitor, EVT-701, decreased the OxPHOS metabolism of murine and human cytarabine (AraC)-resistant leukemic cell lines. Furthermore, we showed that while AraC induced an immune response regulation by increasing CD39 expression and by reinforcing the interferon-γ/PD-L1 axis, EVT-701 reduced CD39 and PD-L1 expression in vitro in a panel of both murine and human AML cell lines, especially upon AraC treatment. Altogether, this work uncovers a non-canonical function of ETCI in controlling CD39 and PD-L1 immune checkpoints, thereby improving the anti-tumor response in AML.

Abstract 1165: Identification of a cholesterol onco-metabolite, promoter of tumor in breast cancers, and of the enzyme involved in its biosynthesis

Breast cancer (BC) is the most common female cancer. Although hormonotherapy (HT), such as Tamoxifen (Tam), is effective for the treatment of most patients with BC expressing estrogen receptors (ER +), resistance to HT is frequent and a number of BC do not express these receptors and do not respond to HT.

The mechanisms responsible for these treatment failures remain unclear, indicating that it is necessary to characterize the molecular actors involved in BC etiology, progression and resistance that will help to improve BC phenotyping and treatment efficacy and to identify new therapeutic targets.

Recent literature highlights that cholesterol metabolism can produce new targets for cancer progression and resistance. We characterized a new pathway in cholesterol metabolism at the level of Cholesterol Epoxide Hydrolase (ChEH). ChEH selectively catalyses the hydrolysis of cholesterol 5,6-epoxides (EC) into cholestan-3β,5α,6β-triol (CT) and is a high affinity target of anti-cancer compounds, such as Tam (de Medina et al, PNAS, 2010). We showed that the enzymatic transformation of EC leads to the production of a tumor suppressor metabolite, dendrogenin A (DDA), involved in the control of cell differentiation and growth, and reported that DDA production is decreased in BC compared with normal tissue (de Medina et al, Nature Commun, 2013, Silvente-Poirot et al, Science, 2014).

The aim of the present study was to characterize further the deregulations of this metabolism and to determine the potential role of ChEH activation in BC progression.

We established that the activity of ChEH in BC cells generates an unexpected metabolite from CT. By using RP-HPLC and GC-MS, we determined this unknown metabolite to be the oxysterol: 6-oxo-cholestan-3β,5α-diol (OCDO). We characterized that OCDO stimulates proliferation in vitro and in vivo of various BC cells expressing or not the ER. Interestingly, OCDO formation in tumor cells and tumors grafted into mice was strongly inhibited by ChEH inhibitors known to have anti-tumor activity such as Tam, PBPE or DDA.

We identified the enzyme responsible for the transformation of CT into OCDO (OCDO synthase). The knock down of OCDO synthase expression using specific shRNA decreased OCDO production and proliferation of MCF7 tumor implanted into mice, and OCDO treatment reversed these inhibitions. Moreover, immunohistology analyses of patient samples indicated that OCDO synthase was overexpressed in tumors compared with normal tissues.

In conclusion, the data obtained indicate that deregulations of the metabolism of cholesterol 5,6-epoxides occur in ER-positive and ER-negative tumor cells to favor OCDO production, an onco-metabolite promoter of BC. Therefore, OCDO, EC and CT production as well as the expression of the enzymes producing these metabolites could be markers of BC and of the efficacy of anti-cancer compounds such as Tam or DDA.

Citation Format: Maud Voisin, Philippe de Medina, Michael R. Paillasse, Magali Lacroix-Triki, Florence Dalenc, Marc Poirot, Sandrine Silvente-Poirot. Identification of a cholesterol onco-metabolite, promoter of tumor in breast cancers, and of the enzyme involved in its biosynthesis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1165. doi:10.1158/1538-7445.AM2015-1165

Targeting cholesterol homeostasis to fight hearing loss: a new perspective

Sensorineural hearing loss (SNHL) is a major pathology of the inner ear that affects nearly 600 million people worldwide. Despite intensive researches, this major health problem remains without satisfactory solutions. The pathophysiological mechanisms involved in SNHL include oxidative stress, excitotoxicity, inflammation, and ischemia, resulting in synaptic loss, axonal degeneration, and apoptosis of spiral ganglion neurons. The mechanisms associated with SNHL are shared with other neurodegenerative disorders. Cholesterol homeostasis is central to numerous pathologies including neurodegenerative diseases and cholesterol regulates major processes involved in neurons survival and function. The role of cholesterol homeostasis in the physiopathology of inner ear is largely unexplored. In this review, we discuss the findings concerning cholesterol homeostasis in neurodegenerative diseases and whether it should be translated into potential therapeutic strategies for the treatment of SNHL.

The NR4A nuclear receptors as potential targets for anti-aging interventions

The development of innovative anti-aging strategy is urgently needed to promote healthy aging and overcome the occurrence of age-related diseases such as cancer, diabetes, cardiovascular and neurodegenerative diseases. Genomic instability, deregulated nutrient sensing and mitochondrial dysfunction are established hallmark of aging. Interestingly, the orphan nuclear receptors NR4A subfamily (NR4A1, NR4A2 and NR4A3) are nutrient sensors that trigger mitochondria biogenesis and improve intrinsic mitochondrial function. In addition, NR4A receptors are components of DNA repair machinery and promote DNA repair. Members of the NR4A subfamily should also be involved in anti-aging properties of hormesis since these receptors are induced by various form of cellular stress and stimulate protective cells response such as anti-oxidative activity and DNA repair. Previous studies reported that NR4A nuclear receptors subfamily is potential therapeutic targets for the treatment of age related disorders (e.g. metabolic syndromes, diabetes and neurodegenerative diseases). Consequently, we propose that targeting NR4A receptors might constitute a new approach to delay aging and the onset of diseases affecting our aging population.

Dendrogenin A arises from cholesterol and histamine metabolism and shows cell differentiation and anti-tumour properties

We previously synthesized dendrogenin A and hypothesized that it could be a natural metabolite occurring in mammals. Here we explore this hypothesis and report the discovery of dendrogenin A in mammalian tissues and normal cells as an enzymatic product of the conjugation of 5,6α-epoxy-cholesterol and histamine. Dendrogenin A was not detected in cancer cell lines and was fivefold lower in human breast tumours compared with normal tissues, suggesting a deregulation of dendrogenin A metabolism during carcinogenesis. We established that dendrogenin A is a selective inhibitor of cholesterol epoxide hydrolase and it triggered tumour re-differentiation and growth control in mice and improved animal survival. The properties of dendrogenin A and its decreased level in tumours suggest a physiological function in maintaining cell integrity and differentiation. The discovery of dendrogenin A reveals a new metabolic pathway at the crossroads of cholesterol and histamine metabolism and the existence of steroidal alkaloids in mammals.

It has been hypothesized that the steroidal alkaloid dendrogenin A (DDA) is a natural metabolite. de Medina et al. show that DDA is produced in mammalian tissues from 5,6α-epoxy-cholesterol and histamine metabolism, and that the compound displays cell differentiation and anti-tumour activities.

Abstract 1884: 6-oxo-cholestan-3β,5α-diol (OCDO) is a metabolite produced in tumors by cholesterol epoxide hydrolase activity and a tumor promoter: OCDO inhibition contributes to the anti-tumor activity of tamoxifen and dendrogenin A

Cholesterol Epoxide Hydrolase (ChEH) selectively catalyses the hydrolysis of 5,6α-epoxy-cholesterol (5,6α-EC) and 5,6β-epoxy-cholesterol (5,6β-EC) into cholestane-3β,5α,6β-triol (CT). We recently reported that the ChEH activity is carried out by the anti-estrogen binding site (AEBS), formed by 3β-hydroxysterol-Δ7-reductase (DHCR7) and 3β-hydroxysterol-Δ8-Δ7 isomerase (D8D7I) (de Medina et al, PNAS, 2010). In the early 70’s, 5,6-ECs were reported to be carcinogenic and mutagenic, but these data were then refuted, and recently we confirmed that 5,6-ECs are stable and non-alkylating substances. Interestingly, it was reported that CT was genotoxic under strong oxidative stress conditions in yeast. This suggested to us that the inhibition of ChEH may protect cells against cytotoxic insults and may contribute to the anti-proliferative and chemopreventive properties of AEBS/ChEH inhibitors such as tamoxifen (Tam), raloxifene or docosahexaenoic acid that accumulated 5,6-ECs at therapeutic doses. These different data suggested a potential role of ChEH activation in cancer. We have explored this hypothesis in the present study. We show here that the activity of ChEH generated an unexpected metabolite from CT in a large panel of cancer cells. By using RP-HPLC and GC-MS, we determined this unknown metabolite to be the oxysterol: 6-oxo-cholestan-3β,5α-diol OCDO). We showed that OCDO stimulated the growth and invasiveness of different tumor cell lines (1.4-fold and 6-fold respectively for MCF7 cells) and the growth and invasiveness of thyroid tumors (TT) or breast cancers (TS/A, MCF7) grafted into mice. Immunohistology of OCDO-treated tumors showed there was an increase in the expression of the proliferation marker Ki67 compared with control tumors. Interestingly, OCDO formation in tumor cells and tumors grafted into mice was strongly inhibited by ChEH inhibitors known to have anti-tumor activity such as Tam, PBPE or Dendrogenin A (DDA), a steroidal alkaloid discovered in our laboratory. The anti-tumor activity of Tam or DDA against breast tumors implanted into mice was completely reversed by co-treatment with OCDO, indicating that inhibition of

ChEH and OCDO production contribute to the anti-tumor mechanism of action of these molecules.

In conclusion, the present study identifies OCDO as being an oxidative metabolite of CT with an uncharacterized role of tumor promoter. The inhibition of OCDO production contributes to the anti-tumor activity of Tam and Dendrogenin A. Thus, the use of these ChEH inhibitors appears as a relevant strategy to block the production of this tumor promoter that may be produced during oxidative stress conditions and inflammation driven carcinogenesis.

Citation Format: Philippe de Medina, Michael R. Paillasse, Maud Voisin, Marc Poirot, Sandrine Silvente-Poirot. 6-oxo-cholestan-3β,5α-diol (OCDO) is a metabolite produced in tumors by cholesterol epoxide hydrolase activity and a tumor promoter: OCDO inhibition contributes to the anti-tumor activity of tamoxifen and dendrogenin A. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1884. doi:10.1158/1538-7445.AM2013-1884

5,6-Epoxy-cholesterols contribute to the anticancer pharmacology of tamoxifen in breast cancer cells

Tamoxifen (Tam) is a selective estrogen receptor modulator (SERM) that remains one of the major drugs used in the hormonotherapy of breast cancer (BC). In addition to its SERM activity, we recently showed that the oxidative metabolism of cholesterol plays a role in its anticancer pharmacology. We established that these effects were not regulated by the ER but by the microsomal antiestrogen binding site/cholesterol-5,6-epoxide hydrolase complex (AEBS/ChEH). The present study aimed to identify the oxysterols that are produced under Tam treatment and to define their mechanisms of action. Tam and PBPE (a selective AEBS/ChEH ligand) stimulated the production and the accumulation of 5,6α-epoxy-cholesterol (5,6α-EC), 5,6α-epoxy-cholesterol-3β-sulfate (5,6-ECS), 5,6β-epoxy-cholesterol (5,6β-EC) in MCF-7 cells through a ROS-dependent mechanism, by inhibiting ChEH and inducing sulfation of 5,6α-EC by SULT2B1b. We showed that only 5,6α-EC was responsible for the induction of triacylglycerol (TAG) biosynthesis by Tam and PBPE, through the modulation of the oxysterol receptor LXRβ. The cytotoxicity mediated by Tam and PBPE was triggered by 5,6β-EC through an LXRβ-independent route and by 5,6-ECS through an LXRβ-dependent mechanism. The importance of SULT2B1b was confirmed by its ectopic expression in the SULT2B1b(-) MDA-MB-231 cells, which became sensitive to 5,6α-EC, Tam or PBPE at a comparable level to MCF-7 cells. This study established that 5,6-EC metabolites contribute to the anticancer pharmacology of Tam and highlights a novel signaling pathway that points to a rationale for re-sensitizing BC cells to Tam and AEBS/ChEH ligands.

Technical note: Hapten synthesis, antibody production and development of an enzyme-linked immunosorbent assay for detection of the natural steroidal alkaloid Dendrogenin A

We have recently discovered the existence of 5α-Hydroxy-6β-[2-(1H-imidazol-4-yl)ethylamino]cholestan-3β-ol, called Dendrogenin A (DDA), as the first endogenous steroidal alkaloid ever described in mammals. We found that the DDA content of tumors and cancer cell lines was low or absent compared with normal cells showing that a deregulation in DDA biosynthesis was associated with cancer and therefore suggesting that DDA could represent a metabolomic cancer biomarker. This prompted us to produce antibodies that selectively recognize DDA. For this purpose, the hapten 5α-hydroxy-6β-[2-(1H-imidazol-4-yl)ethylamino]cholestan-3β-o-hemisuccinate with a carboxylic spacer arm attached to the 3β-hydroxyl group of DDA was synthesized. The hapten was coupled to bovine serum albumin and keyhole limpet hemocyanin for antibody production to develop an enzyme-linked immunosorbent assay (ELISA). The protein conjugates were injected into BALB/c mice to raise antibodies. The monoclonal antibodies that were secreted from the hybridoma cell lines established were assessed with indirect ELISA by competitive assays using dilutions of a DDA standard. The antibodies from the selected hybridomas had an IC(50) value ranging from 0.8 to 425 ng/ml. Three antibodies showed no cross-reactivity with structurally related compounds including histamine, cholesterol, ring B oxysterols and a regio-isomer of DDA. In this study, high-affinity and selective antibodies against DDA were produced for the first time, and a competitive indirect ELISA was developed.

Surprising unreactivity of cholesterol-5,6-epoxides towards nucleophiles

We recently established that drugs used for the treatment and the prophylaxis of breast cancers, such as tamoxifen, were potent inhibitors of cholesterol-5,6-epoxide hydrolase (ChEH), which led to the accumulation of 5,6α-epoxy-cholesterol (5,6α-EC) and 5,6β-epoxy-cholesterol (5,6β-EC). This could be considered a paradox because epoxides are known as alkylating agents with putative carcinogenic properties. We report here that, as opposed to the carcinogen styrene-oxide, neither of the ECs reacted spontaneously with nucleophiles. Under catalytic conditions, 5,6β-EC remains unreactive whereas 5,6α-EC gives cholestan-3β,5α-diol-6β-substituted compounds. These data showed that 5,6-ECs are stable epoxides and unreactive toward nucleophiles in the absence of a catalyst, which contrasts with the well-known reactivity of aromatic and aliphatic epoxides. These data rule out 5,6-EC acting as spontaneous alkylating agents. In addition, these data support the existence of a stereoselective metabolism of 5,6α-EC.

Signaling through cholesterol esterification: a new pathway for the cholecystokinin 2 receptor involved in cell growth and invasion

Several studies indicate that cholesterol esterification is deregulated in cancers. The present study aimed to characterize the role of cholesterol esterification in proliferation and invasion of two tumor cells expressing an activated cholecystokinin 2 receptor (CCK2R). A significant increase in cholesterol esterification and activity of Acyl-CoA:cholesterol acyltransferase (ACAT) was measured in tumor cells expressing a constitutively activated oncogenic mutant of the CCK2R (CCK2R-E151A cells) compared with nontumor cells expressing the wild-type CCK2R (CCK2R-WT cells). Inhibition of cholesteryl ester formation and ACAT activity by Sah58-035, an inhibitor of ACAT, decreased by 34% and 73% CCK2R-E151A cell growth and invasion. Sustained activation of CCK2R-WT cells by gastrin increased cholesteryl ester production while addition of cholesteryl oleate to the culture medium of CCK2R-WT cells increased cell proliferation and invasion to a level close to that of CCK2R-E151A cells. In U87 glioma cells, a model of autocrine growth stimulation of the CCK2R, inhibition of cholesterol esterification and ACAT activity by Sah58-035 and two selective antagonists of the CCK2R significantly reduced cell proliferation and invasion. In both models, cholesteryl ester formation was found dependent on protein kinase zeta/ extracellular signal-related kinase 1/2 (PKCzeta/ERK1/2) activation. These results show that signaling through ACAT/cholesterol esterification is a novel pathway for the CCK2R that contributes to tumor cell proliferation and invasion.