[From high content screening to target deconvolution: New insights for phenotypic approaches]

The advent of the molecular biology and the completion of the human genome sequencing prompted the pharmaceutical industry to progressively implement target-centric drug discovery strategies. However, concerns regarding the research and development productivity during the last ten years, combined with technological developments in high-content screening, automation, image analysis and artificial intelligence triggered a renewed interest for the phenotypic drug discovery approaches. Target-centric and phenotypic approaches are more and more considered complementary, hence, positioning the target deconvolution on the critical path. This review analyzes the evolution of the target-centric and phenotypic approaches, focusing more specifically on the high-content screening and the target deconvolution technologies currently available.

Abstract 1487: Investigation of triple-negative breast cancer tumor conversion through high-content screening approaches

Among Breast Cancer (BC) classification, Triple-Negative (TN) form is the most aggressive, lacking efficient and specific treatment. Our project aims at investigating the possibility to convert TNBC tumor cell lines in Estrogen Receptor (ER), Progesterone Receptor (PR) and/or Human Epidermal growth factor Receptor 2 (HER2)-positive cells using various modalities (siRNA, CRISPR-Cas9, small molecules). Our approach consists in optimizing a multi-parametric High-Content Screening (HCS) relying on phenotypic read-outs such as expression of TNBC positive and negative markers, cell behavior and viability. This poster will present our initial results, validation and future plans. This thesis project fits within a context of drug discovery, innovation, comparison of technologies and understanding of key biological processes and pathways, carried out in partnership between Servier Research Institute and Institut Curie.

Citation Format: Albane Gaudeau, Véronique Lamamy, Anne-Laure Jaskowiak, Xavier Scerri, Benjamin Chanrion, Thierry Dorval, Elaine Del Nery, Franck Perez, Jacques Camonis, Jean-Philippe Stéphan. Investigation of triple-negative breast cancer tumor conversion through high-content screening approaches [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1487.

In vitro regulation of an inducible-type NO synthase in the rat seminiferous tubule cells

Rat Sertoli cells express an inducible nitric oxide synthase isoform (iNOS) in response to the combined addition of the cytokines--interferon gamma (IFNgamma), tumor necrosis factor alpha (TNF alpha), interleukin-1alpha (IL-1alpha)--and lipopolysaccharides (LPS). We demonstrated that the addition of cytokines and lipopolysaccharides (C+L) to cultured peritubular cells resulted in high nitrite and iNOS mRNA levels, indicating the induction of an iNOS isoform. This enzyme was not induced in cultured pachytene spermatocytes or spermatids. Nitrite production in Sertoli cells and peritubular cells required both IFNgamma and TNF alpha and was potentiated by LPS, whereas IL-1alpha was ineffective. The induction of nitrite production and iNOS mRNA by IFNgamma+TNF alpha+LPS could be further enhanced by basic fibroblast growth factor in Sertoli cells but not in peritubular cells. In contrast, transforming growth factor beta markedly reduced this induction in peritubular cells but had no effect on Sertoli cells. FSH positively modulated the C+L-induced iNOS in Sertoli cells. Dibutyryl cAMP had a synergistic effect with C+L on NOS activity in both Sertoli cells and peritubular cells. In contrast, testosterone did not influence basal or induced NOS activity in these two cell types. These data show that NOS activity in the somatic cells of the seminiferous tubules is induced and regulated by multiple factors that act in combination, and suggest that nitric oxide may participate in the endocrine and paracrine control of testicular function.

Regulation of Sertoli cell IL-1 and IL-6 production in vitro

Interleukin-1 (IL-1) and IL-6 are pleiotropic cytokines produced by a large variety of cell types. In the testis, Sertoli cells produce IL-1alpha and IL-6. Previous studies have demonstrated that, in vitro, Sertoli cell IL-1alpha production is stimulated by some inducers of macrophage IL-1, as well as by phagocytosis of residual bodies. Furthermore, we have also shown that IL-1alpha is able to enhance Sertoli cell IL-6 production by an autocrine action. The aim of the present study was to further investigate the regulation of Sertoli cell IL-1 and IL-6 production. Three categories of potential regulators were tested; the lipopolysaccharide (LPS) and the yeast extract zymosan; follicle stimulating hormone (FSH), testosterone and dexamethasone; tumor necrosis factor alpha (TNFalpha), interferon gamma (IFNgamma) and the nerve growth factor beta (NGFbeta). It was found that zymosan (400-800 microg/ml) and LPS (20 microg/ml) stimulated Sertoli cell IL-1 and IL-6 production. FSH (1 x 10(-2)-1 microg/ml) and NGF (25-200 ug/ml) stimulated Sertoli cell IL-6 levels in a dose-dependent manner but had no effect on IL-1. The effect of testosterone on Sertoli cell IL-1 and IL-6 secretion was biphasic: dramatic increased secretion with low concentrations (0.01-1 nM) and no effect with the higher concentration tested (100 nM). Dexamethasone reduced LPS-induced IL-1 and IL-6 production in a concentration-responsive manner (0.04-0.4 and 0.4-40 ng/ml, respectively). Addition of TNFalpha to Sertoli cells resulted in a dose-dependent increase of both cytokines (50-100 U/ml for IL-1, 100-200 U/ml for IL-6). In the case of IFNgamma, intermediate concentrations (50-100 U/ml) stimulated IL-1alpha, whereas the highest concentrations (200-400 U/ml) inhibited IL-6. It is concluded that regulation of Sertoli cell IL-1 and IL-6 is very complex as it involves factors as different as hormones, paracrine factors and activators of macrophages. The latter agents may be mimicking the action of pathogens or the action of intratesticular agents whose nature remains to be elucidated.

Nitric oxide production by Sertoli cells in response to cytokines and lipopolysaccharide

Nitric oxide (NO) is formed from L-arginine residues by nitric oxide synthase (NO Synthase) in many types of cells and acts as an intercellular messenger in several physiological systems. In the present study, we demonstrate that a combination (CL) of interleukin-1 alpha, interferon gamma, tumor necrosis factor alpha and lipopolysaccharide induces nitrite (NO2) production in cultured rat Sertoli cells. This biosynthesis of NO2- requires a lag time period of 18 hr and then increases for at least 96 hr; it is prevented by two NO Synthase inhibitors, NG-monomethyl-L-arginine and aminoguanidine. Northern blot analysis shows the induction of a macrophage-like NO Synthase mRNA synthesis in Sertoli cells cultured for a minimum of 6 hr in the presence of CL, with maximal levels after 12 to 30 hr of incubation. These results indicate for the first time that cultured rat Sertoli cells express an inducible NO Synthase isoform in response to a combination of cytokines and lipopolysaccharide.

Residual bodies activate Sertoli cell interleukin-1 alpha (IL-1 alpha) release, which triggers IL-6 production by an autocrine mechanism, through the lipoxygenase pathway

Interleukin-1 (IL-1) and IL-6 are produced by Sertoli cells. As IL-1 stimulates IL-6 production in some tissues, the cascade of events that results in IL-6 secretion by Sertoli cells was studied. The addition of IL-1 alpha to Sertoli cells resulted in a time-dependent increase in IL-6 secretion. Incubation of Sertoli cells with two known stimulators of IL-1 production, lipopolysaccharide (LPS) and residual bodies, resulted in a significant increase in IL-1 release into the medium several hours before IL-6 release. That IL-1 is essential for IL-6 production from Sertoli cells was established by blocking the actions of LPS and residual bodies with an anti-IL-1 alpha antibody. An increase in the release of IL-1 before IL-6 was also observed in medium obtained from staged segments of intact seminiferous tubules; IL-1 reached a maximum level at stage VIII, when mature spermatozoa are released and residual bodies are formed and phagocytosed. The secretion of IL-6 was low during this stage and then increased progressively from stage IX onward, consistent with IL-1 stimulation of IL-6. The pathway of IL-1 alpha-induced release of IL-6 was studied in the presence of agents that influence arachidonic acid release and metabolism. IL-1 alpha was found to stimulate arachidonic acid release by Sertoli cells. Furthermore, a phospholipase A2 inhibitor, aristolochic acid, significantly decreased IL-1-, LPS-, and pyrularia pubera thionin-induced IL-6 secretion from Sertoli cells. Indomethacin, a specific inhibitor of the cyclooxygenase pathway, had no significant effect on basal, but enhanced IL-1- and LPS-stimulated IL-6 production. The involvement of arachidonic acid metabolites produced in the lipoxygenase pathway on the release of IL-6 was investigated indirectly, using nordihydroguaiaretic acid. This inhibitor reduced basal and IL-1 alpha- and LPS-stimulated IL-6 production. Ethacrynic acid, an inhibitor of peptido-leukotriene synthesis, also reduced basal IL-6 levels and blocked IL-1 alpha- as well as LPS-induced IL-6 secretion. It is concluded that IL-1 produced by Sertoli cells in response to LPS or residual bodies induces IL-6 through the lipoxygenase pathway.