Treatment with a programmed cell death-1-specific antibody has little effect on afatinib- and naphthalene-induced acute pneumonitis in mice

Impact of EGFR-TKIs combined with PD-L1 antibody on the lung tissue of EGFR-driven tumor-bearing mice

OBJECTIVES

EGFR-targeted tyrosine kinase inhibitors (TKIs) have been the standard treatment for non-small cell lung cancer patients with EGFR mutations. However, most patients eventually develop resistance. With the development of immune checkpoint inhibitors targeting the programmed cell death receptor/ligand 1 (PD-1/PD-L1), there is a growing interest in developing combination strategies. However, there are concerns that the combination of a PD-(L)1 inhibitor and EGFR-TKI may be associated with an increased risk of pneumonitis. Therefore, we utilized an established EGFR-driven tumor-bearing mouse model to investigate whether the combination would induce pneumonitis in mouse lung tissue.

MATERIALS AND METHODS

Mice were treated with monotherapy or combined therapy of PD-L1 antibody and EGFR-TKIs including first-generation gefitinib and third-generation osimertinib. Bronchoalveolar lavage fluids (BALFs) and lung tissues were collected for analysis at the end of treatment.

RESULTS AND CONCLUSION

The osimertinib and anti-PD-L1 combined treatment group had the highest inflammation scores in pathologic grades of H&E staining of lung tissue and had the highest percentages of myeloperoxidase positive cells. However, combining gefitinib and anti-PD-L1 treatment appeared to not increase the level of pneumonitis in mice. Total cell counts, neutrophil counts and total protein concentration in BALFs were also significantly increased in the osimertinib and anti-PD-L1 combined treatment group. We next evaluated proinflammatory factors in BALFs. The levels of IFN-γ, IL-2, IL-5, TNF-α and IL-12p70 were increased in osimertinib and anti-PD-L1 combined treatment group. Comparison of different sequences of drug administration demonstrated that mice treated with osimertinib followed by PD-L1 antibody did not show evident lung inflammation. Our findings indicate that osimertinib, rather than gefitinib combined with anti-PD-L1 treatment could lead to lung injury in an EGFR mutated tumor-bearing mouse model. The sequence and timing of combining EGFR-TKI and PD-L1 antibody may influence the severity of pneumonitis.

Anti-PD1 up-regulates PD-L1 expression and inhibits T-cell lymphoma progression: possible involvement of an IFN-γ-associated JAK-STAT pathway

Purpose

NK/T-cell neoplasms are rare, highly aggressive, and insensitive to chemotherapy. These lymphomas have a poor prognosis, with patients being vulnerable to relapse. Hence, there is a need for alternative treatments. The purpose of this study is to investigate whether anti-PD1 takes effect on NK/T cell lymphoma.

Methods

The expression of PD-L1 in NK/T cell lines was investigated by flow cytometry and by Western blot. In vivo, overall survival and median survival time of mice bearing an NK/T cell line tumor was assessed. Tumor-infiltrating T cells and monocyte-derived suppressor cells were evaluated by flow cytometry. Levels of PD-L1 and components of the JAK-STAT pathway were assessed in tumor tissues by immunohistochemistry.

Results

NK/T cell lines had greater expression of PD-L1 than normal peripheral blood human NK cells. In vivo, anti-PD1 treatment improved overall survival and median survival time of mice bearing an NK/T cell line. Furthermore, anti-PD1 treatment increased levels of PD-L1. Cultured tumor-infiltrating lymphocytes from mice treated with anti-PD1 had greater levels of IFN-γ than cultured lymphocytes from untreated animals. Further, levels of JAK2 and STAT1 were greater in mice treated with anti-PD1.

Conclusion

In vivo, anti-PD1 inhibited the progression of an NK/T-cell lymphoma and up-regulated PD-L1 expression. This up-regulation may be through the IFN-γ-associated JAK-STAT pathway.