Programmed cell death protein 1 and programmed death-ligand 1 are expressed on the surface of some small-cell lung
Hiromichi Yamane1, Hideko Isozaki2, Masami Takeyama1
1Department of General Internal Medicine 4, Kawasaki Medical School 2-1-80 Nakasange, Kita-ku, Okayama 700-8505, Japan.
Introduction:
Programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) play a major role in suppressing the immune system during the formation of the PD-1/PD-L1 pathway, which transmits an inhibitory signal to reduce T cell activity. PD-L1 is often expressed in various malignant tumors. In contrast, PD-1 is generally observed in activated lymphocytes and myeloid-derived dendritic cells. Of the malignant cells, only Jurkat cells under special conditions and angioimmunoblastic T-cell lymphoma tissue cells express PD-1 on their surface.
Methods:
To clarify whether the PD-1/PD-L1 pathway participates in the immunotolerance of small-cell lung cancer (SCLC) cells, we examined the expressions of PD-1 and PD-L1 on the cell surface of SCLC cell lines using flow cytometry and reverse transcription polymerase chain reaction.
Results:
Among the four SCLC cell lines examined, only SBC-3 expressed both PD-1 and PD-L1.
Conclusions:
We demonstrated that both PD-1 and PD-L1 molecules were co-expressed on the surface of SCLC cells. Although the biological implications of this remain unclear, we speculate that PD-1 and its ligand on the SCLC cells may participate in the growth inhibition of tumor cells as reported in cytotoxic T cells.
Insights
Small-cell lung cancer (SCLC) cells express both programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1). This co-expression on SCLC cells may influence tumor growth and immune evasion.
Area of Science:
- Oncology
- Immunology
- Molecular Biology
Background:
- The programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) pathway is crucial in immune suppression, inhibiting T cell activity.
- PD-L1 is frequently found on malignant tumors, while PD-1 is typically on immune cells, with limited expression on cancer cells.
Purpose of the Study:
- To investigate the involvement of the PD-1/PD-L1 pathway in the immune tolerance of small-cell lung cancer (SCLC).
- To determine the expression of PD-1 and PD-L1 on SCLC cell lines.
Main Methods:
- Utilized flow cytometry to detect cell surface expression of PD-1 and PD-L1.
- Employed reverse transcription polymerase chain reaction (RT-PCR) to analyze gene expression of PD-1 and PD-L1.
Main Results:
- Out of four SCLC cell lines studied, only the SBC-3 cell line exhibited co-expression of both PD-1 and PD-L1 on its surface.
- Confirmed the presence of both PD-1 and PD-L1 molecules on SCLC cells.
Conclusions:
- Demonstrated co-expression of PD-1 and PD-L1 on SCLC cell surfaces.
- Speculated that PD-1 and its ligand on SCLC cells might contribute to tumor growth inhibition, potentially by mimicking effects seen in cytotoxic T cells, though further research is needed to clarify the biological implications.
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