Background: Programmed cell death protein-1 (PD-1) and programmed death ligand-1 (PD-L1) play a major role in suppressing the immune system by forming the PD-1/PD-L1 complex, which transmits an inhibitory signal to reduce T-cell activity. PD-L1 is often expressed in various malignant tumors. On the other hand, 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.
Purpose: To clarify whether PD-1/PD-L1 complex participates in the immunotolerance on small-cell lung cancer (SCLC) cells.
Materials and methods: We examined the expression levels of PD-1 and PD-L1 on the cell surface of SCLC cell lines using flowcytometry and reverse transcription polymerase chain reaction. Subsequently, the soluble PD-L1 (sPD-L1) concentration was measured using enzyme-linked immunosorbent assay, and the cell growth inhibitory effect of IFN-γ was determined by direct cell counting using a hemocytometer and Trypan blue staining.
Results: Among the four SCLC cell lines examined, only SBC-3 cells expressed both PD-1 and PD-L1. The sPD-L1 concentrations in culture medium gradually increased according to cell growth. Although IFN-γ alone inhibited the growth of SBC-3 cells, PD-L1 expression on the cell surface was not induced by IFN-γ.
Conclusions: We demonstrated that both PD-1 and PD-L1 molecules are 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 is reported in cytotoxic T cells.
Citation Format: Hiromichi Yamane, Hideko Isozaki, Nobuaki Ochi, Kenichiro Kudo, Yoshihiro Honda, Tomoko Yamagishi, Toshio Kubo, Katsuyuki Kiura, Nagio Takigawa. Both programmed cell death protein 1 and programmed death-ligand 1 molecules can be expressed on the cell surface of small-cell lung cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1323. doi:10.1158/1538-7445.AM2015-1323
BackgroundDocetaxel is a key antineoplastic drug for treatment of non-small cell lung cancer. Ocular adverse events of docetaxel include epiphora (excess tearing) and conjunctivitis. Epiphora has been reported to be associated with canalicular and nasolacrimal duct stenosis, but it is not necessarily caused by lacrimal duct obstruction.Case presentationWe encountered three Japanese non-small cell lung cancer patients who developed epiphora after the administration of docetaxel-based chemotherapy. One patient with lacrimal puncta stenosis showed improvement with probing and irrigation. The other two patients resolved following cessation of docetaxel or administration of artificial tears.ConclusionAs epiphora can interfere with activities of daily life and negatively affect quality of life, it is important for thoracic oncologists to be aware of this adverse event.
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