CD95/Fas ligand (FasL) is a cell death-promoting member of the tumor necrosis factor family with important functions in the regulation of T-cell homeostasis and cytotoxicity. In T cells, FasL expression is tightly regulated on a transcriptional level involving a complex set of different transcription factors. The orphan nuclear receptor liver receptor homolog-1 (LRH-1/NR5a2) is involved in the regulation of development, lipid metabolism and proliferation and is predominantly expressed in epithelial tissues. However, its expression in T lymphocytes has never been reported so far. Based onin silicoanalysis, we identified potential LRH-1 binding sites within theFASLGpromoter. Here, we report that LRH-1 is expressed in primary and secondary lymphatic tissues, as well as in CD4⁺and CD8⁺T cells. LRH-1 directly binds to its binding sites in theFASLGpromoter, and thereby drivesFASLGpromoter activity. Mutations in the LRH-1 binding sites reduceFASLGpromoter activity. Pharmacological inhibition of LRH-1 decreases activation-induced FasL mRNA expression, as well as FasL-mediated activation-induced T-cell apoptosis and T-cell cytotoxicity. In a mouse model of Concanavalin A-induced and FasL-mediated hepatitis pharmacological inhibition of LRH-1 resulted in decreased hepatic FasL expression and a significant reduction of liver damage. In summary, these data show for the first time LRH-1 expression in T cells, its role inFASLGtranscription and the potential of pharmacological inhibition of LRH-1 in the treatment of FasL-mediated immunopathologies.

Ring-substituted 1-hydroxynaphthalene-2-carboxanilides were previously investigated for their antimycobacterial properties. In our study, we have shown their antiproliferative and cell death-inducing effects in cancer cell lines. Cell proliferation and viability were assessed by WST-1 assay and a dye exclusion test, respectively. Cell cycle distribution, phosphatidylserine externalization, levels of reactive oxygen or nitrogen species (RONS), mitochondrial membrane depolarization, and release of cytochrome c were estimated by flow cytometry. Levels of regulatory proteins were determined by Western blotting. Our data suggest that the ability to inhibit the proliferation of THP-1 or MCF-7 cells might be referred to meta- or para-substituted derivatives with electron-withdrawing groups -F, -Br, or -CF₃ at anilide moiety. This effect was accompanied by accumulation of cells in G1 phase. Compound 10 also induced apoptosis in THP-1 cells in association with a loss of mitochondrial membrane potential and production of mitochondrial superoxide. Our study provides a new insight into the action of salicylanilide derivatives, hydroxynaphthalene carboxamides, in cancer cells. Thus, their structure merits further investigation as a model moiety of new small-molecule compounds with potential anticancer properties.

This study explores biocompatible amino‐functionalized gold nanoparticles (Au‐NH₂) as nanotherapeutics for the selective eradication of leukemia cells, elucidates the mechanism of cytotoxicity, and it confirms in vivo efficacy of the engineered nanomaterial. Au‐NH₂ trigger apoptotic cell death of myeloid leukemia cell lines and primary acute myeloid leukemia (AML) cells by i) inhibition of mitochondrial respiration, ii) ATP depletion, iii) loss of mitochondrial membrane potential, and iv) mitochondrial release of cytochrome c. Au‐NH₂ act selectively on leukemia cells inasmuch as the viability of normal peripheral blood mononuclear cells and macrophages as well as the colony formation of hematopoietic stem cells remain basically unaffected. The selectivity of Au‐NH₂ for AML cells can be attributed to both the preferential accumulation of AuNH₂ in AML cells and the strong dependence of those cells on mitochondrial oxidative phosphorylation for ATP production. Importantly, Au‐NH₂ applied either as monotherapy or as a cytarabine combination regimen possess antileukemic efficacy in the absence of adverse events in mice xenografted with primary human AML in vivo. The engineered material may pave the way for a novel nanotherapeutic treatment of AML.