CD95 ligand mediates T-cell receptor-induced apoptosis of a CD4+ CD8+ double positive thymic lymphoma

Abstract

Tumors in the thymus can be of different cellular origin. Among the most common tumors are thymoma and lymphoma, which are derived from transformed thymic epithelial cells and transformed lymphocytes, respectively. Thymic lymphoma and their response to apoptotic stimuli are poorly characterized. Here, we analyse apoptosis events in the thymic lymphoma cell line Thy278, which expresses cell surface antigens characteristic of immature double positive thymocytes. Upon T-cell receptor (TCR)/ CD3 stimulation, Thy278 cells die by apoptosis, similar as primary thymocytes during negative selection. Caspases are crucial for deletion of both Thy278 cells and normal thymocytes. Moreover, we show that deletion of primary thymocytes and Thy278 cells upon CD3 stimulation is considerably impaired by neutralizing CD95L antibody. Thus, our results not only demonstrate that TCR-induced apoptosis is still functional in transformed thymocytes, but also suggest that Thy278 cells are a helpful model for the molecular analysis of negative selection.

Thalidomide Induces Limb Anomalies by PTEN Stabilization, Akt Suppression, and Stimulation of Caspase-Dependent Cell Death

“…Proteins were extracted from HEFs or limb buds (for one sample, limb buds were pooled from 15 embryos) as described before (34). Thirty micrograms (HEFs) or 5 g (limb buds) protein was used in the caspase glo assay to measure caspase-3 and -7 activity according to the instructions of the manufacturer (Promega, Heidelberg, Germany).…”

Thalidomide Induces Limb Anomalies by PTEN Stabilization, Akt Suppression, and Stimulation of Caspase-Dependent Cell Death

“…Isolation of PLBCs and HEFs and preincubation before drug treatment was done as described previously (20). Treatment with thalidomide (38.7 M), human BMP4 (300 ng/ml; R&D Systems, Minneapolis, MN), mouse Noggin (300 ng/ml; R&D Systems), anti-human DKK1 antibody (350 ng/ml; R&D Systems), bpV(pic), insulin, cycloheximide (CHX) (10 g/ml; Sigma), MG132 (10 M; Calbiochem, Darmstadt, Germany), wortmannin (10 nM; Alexis), PD98059 (10 M; Calbiochem), caspase inhibitors [quinoline-Val-Asp (OCH 3 )-CH 2 -O-Ph (QVD-oPh), N-acetyl-Val-Asp (OMe)-Val-Ala-Asp (OMe)-fluoromethyl ketone (zVDVAD-fmk), N-acetyl-Ile-Glu (OMe)-Thr-Asp (OMe)-fluoromethyl ketone (zIETD-fmk), and N-acetyl-Leu-Glu (OMe)-His-Asp (OMe)-fluoromethyl ketone (zLEHD-fmk); MP Biomedicals, Heidelberg, Germany; all used at 20 M], anti-TNF-R1 (10 g/ml) (42), anti-FasL (10 g/ml) (34), and anti-TRAIL antibodies (10 g/ml) (clone 2E5) (ALX-804-296; Alexis) was performed in OptiMEM1 (Invitrogen, Carlsbad, CA) plus 1% fetal calf serum. Unless otherwise noted, all treatments were done for 6 hours.…”

A Role for Stroma-Derived Annexin A1 as Mediator in the Control of Genetic Susceptibility to T-Cell Lymphoblastic Malignancies through Prostaglandin E2 Secretion

“…+ thymocytes (28). Significant apoptosis was only detected 24 hours after treatment with 100 Amol/L PGE 2 (Fig.…”