Related Experiment Video
Updated: Jul 13, 2026
Identification of Mediators of T-cell Receptor Signaling via the Screening of Chemical Inhibitor Libraries
Published on: January 22, 2019
Lung carcinomas do not induce T-cell apoptosis via the Fas/Fas ligand pathway but down-regulate CD3 epsilon
Heriberto Prado-Garcia1, Dolores Aguilar-Cazares, Manuel Meneses-Flores
1Departamento de Enfermedades Cronico-Degenerativas, Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas, Tlalpan 4502, Col. Seccion XVI, CP 14080 Mexico City, Mexico.
Background:
Non-small cell lung carcinoma (NSCLC) patients have impaired cellular immune responses. It has been hypothesized that tumor cells expressing Fas Ligand (FasL) induce in T lymphocytes: (a) apoptosis (tumor counterattack) and (b) down-regulation of CD3zeta expression. However, the hypothesis of tumor counterattack is still controversial.
Methods:
We analyzed FasL expression on NSCLC cell lines and on tumor cells from lung adenocarcinoma patients by flow cytometry and immunocytochemistry. FasL mRNA expression was detected in NSCLC cell lines using RT-PCR, and functional FasL was evaluated on Fas-expressing Jurkat T-cells by annexin-V-FITC staining and by SubG(1) peak detection. Also, the proapoptotic effect of microvesicles released from NSCLC cell lines in Jurkat T-cells was studied. Alterations in the expression levels of CD3zeta, CD3epsilon, and CD28 [measured as mean fluorescence intensity (MFI)] were determined in Jurkat T-cells after co-culture with NSCLC cell lines or tumor-derived microvesicles. Furthermore, the expression levels of CD3zeta and CD3epsilon in CD4+T and CD8+T lymphocytes from lung adenocarcinoma patients was studied.
Results:
Our results indicate that NSCLC cells neither FasL expressed nor induced apoptosis in Jurkat T-cells. Tumor-derived microvesicles did not induce apoptosis in Jurkat T-cells. In contrast, NSCLC cell lines down-regulated CD3epsilon but not CD3zeta chain expression in Jurkat T-cells; this effect was induced by soluble factors but not by microvesicles. In lung adenocarcinoma patients, significant decreases of MFI values for CD3epsilon, but not CD3zeta, were found in CD4+T and CD8+T cells from pleural effusion compared to peripheral blood and in peripheral blood of patients compared to healthy donors.
Conclusions:
Our data do not support the tumor counterattack hypothesis for NSCLC. Nonetheless, down-regulation of CD3epsilon in T-cells induced by NSCLC cells might lead to T-cell dysfunction.
Insights
Non-small cell lung carcinoma cells do not express Fas Ligand or induce apoptosis. However, they do reduce CD3epsilon expression in T-cells, potentially impairing immune responses in lung cancer patients.
Area of Science:
- Immunology
- Oncology
- Cell Biology
Background:
- Non-small cell lung carcinoma (NSCLC) is associated with impaired T-cell immunity.
- The tumor counterattack hypothesis suggests NSCLC cells expressing Fas Ligand (FasL) induce T-cell apoptosis and CD3zeta down-regulation.
Purpose of the Study:
- To investigate the expression and function of FasL in NSCLC cells.
- To determine if NSCLC cells or their derived microvesicles induce apoptosis or alter T-cell receptor complex component expression (CD3zeta, CD3epsilon) in T-cells.
- To assess T-cell immune marker expression in lung adenocarcinoma patients.
Main Methods:
- Flow cytometry and immunocytochemistry to analyze FasL expression on NSCLC cell lines and patient tumor cells.
- RT-PCR for FasL mRNA detection.
- Functional assays using Jurkat T-cells to assess apoptosis and CD3zeta/CD3epsilon expression changes after co-culture with NSCLC cells or microvesicles.
- Analysis of CD3zeta and CD3epsilon expression in T-cells from lung cancer patients.
Main Results:
- NSCLC cell lines did not express detectable FasL and did not induce apoptosis in Jurkat T-cells.
- Tumor-derived microvesicles also failed to induce apoptosis in T-cells.
- NSCLC cells, via soluble factors, down-regulated CD3epsilon expression but not CD3zeta in Jurkat T-cells.
- Lung adenocarcinoma patients exhibited decreased CD3epsilon expression in CD4+ and CD8+ T-cells from pleural effusion and peripheral blood compared to healthy donors.
Conclusions:
- The findings do not support the tumor counterattack hypothesis in NSCLC.
- Down-regulation of CD3epsilon in T-cells by NSCLC cells may contribute to T-cell dysfunction in lung cancer patients.
Related Concept Videos
01:17The Extrinsic Apoptotic Pathway
01:31The Intrinsic Apoptotic Pathway
01:15Receptor Downregulation in MVBs
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR activation may...