These data indicate a possible role for targeting of the IL-6/IL-6R pathway in the treatment of NSCLC, particularly in patients with early stage disease. and analyzed for cytokines by ELISA. Na?ve monocytes were stimulated with brain metastasis conditioned media to evaluate PD-L1 stimulation. Results: Patients with brain metastatic lung carcinoma exhibited increased peripheral monocyte PD-L1, MDSC abundance, and Treg percentage compared to early stage pre-metastatic patients and healthy controls. Patients with elevated peripheral monocyte PD-L1 had less reactive T cells and worse survival. Brain metastasis conditioned media stimulation increased monocyte PD-L1, and conditioned media IL-6 levels correlated with PD-L1 induction. Treatment with anti-IL-6 or anti-IL-6 receptor antibodies reduced PD-L1 expression. In summary, patients with lung cancer and brain metastases exhibit multiple markers of peripheral immunosuppression. Conclusions: Tumor-derived IL-6 was capable of inducing immunosuppressive PD-L1+ myeloid cells, which correlated with worse outcomes. Therefore, monitoring of immunosuppressive factors in peripheral blood may suggest new targets for therapeutic intervention in selected patients. test or ANOVA. The Kaplan-Meier method was used to estimate survival distributions. Survival differences between groups were assessed using the log-rank test, and hazard ratios were calculated by a univariate analysis. P-values 0.05 were considered statistically significant. Results Daurinoline Patients To study the correlation between peripheral immune phenotype and metastasis to the brain, banked blood samples from adenocarcinoma patients undergoing surgical resection of their primary lung tumors (stage I/II) or brain metastases (stage IV) were obtained. Peripheral blood samples were available from a total of 49 patients; 15 patients with stage I/II lung adenocarcinoma and 34 patients with stage IV brain-metastatic lung adenocarcinoma. Patient characteristics are presented in Table 1. The median age for patients with early stage NSCLC was 68 years versus 66 years for patients with brain-metastatic NSCLC (p=0.16). TEAD4 Of the 15 early stage patients, 11 (73%) were female; of the 34 patients with brain metastases, 21 (62%) were female. Smoking history and prevalence of driver mutations were not significantly different between patients with early stage or brain-metastatic NSCLC. Table 1 Clinical characteristics of patients included in this study = 15 (%)= 34 (%)Anaplastic Daurinoline lymphoma kinase, Eastern Cooperative Oncology Group, epidermal growth factor receptor, Kirsten rat sarcoma viral oncogene, pack-year Peripheral immunosuppression in patients with brain-metastatic NSCLC To evaluate the degree of peripheral immunosuppression, PD-L1 expression on circulating myeloid cells (CD45+,CD11b+,PD-L1+), MDSC abundance (CD33+,CD11b+,HLA-DRlow), and Treg percentage (CD3+,CD4+,CD25+,FoxP3+) in patients with brain metastases were evaluated via flow cytometry. Patients with brain metastases had significantly elevated peripheral monocyte PD-L1 expression compared to healthy controls and non-metastatic NSCLC patients (p 0.0001) (Fig 1A, ?,B).B). Due to limited availability of PBMC samples, MDSC abundance and Treg percentage were only analyzed in patients with brain metastases and healthy controls. Mean MDSC abundance was 5.7% in healthy controls and 18.0% in patients with brain metastases (p=0.0002) (Fig 1C, ?,D).D). Mean Treg percentage among CD4+ cells was 4.6% in healthy controls and 7.9% in patients with brain metastases (p=0.029) (Fig 1E, ?,FF). Open in a separate window Physique 1: Patients with brain metastases exhibit increased circulating immunosuppressive cells.(A) Representative gating scheme for identification of myeloid cells from peripheral blood leukocytes (PBL) by flow cytometry. Live cells were gated from the total population (left), followed by identification of single cells (not shown), gating for total myeloid populace of CD45+/CD11b+ cells (center), and gating for PD-L1+ myeloid cells (right). (B) Summary of PD-L1 expression in monocytes from each of the 6 healthy donors, 15 early stage NSCLC patients, and 34 brain-metastatic NSCLC patients. Patients with brain metastases had increased peripheral monocyte PD-L1 (**** p 0.0001). (C) Representative gating scheme for identification of MDSCs from PBLs by flow cytometry. Monocytes were gated from the Daurinoline total population (left), followed by identification of single cells (not shown), gating for total myeloid populace of CD33+/CD11b+ cells (center), and gating for MDSCs (HLA-DRlo; right). (D) Summary of MDSC abundance; patients with brain metastases had increased MDSCs Daurinoline (*** p 0.0005). (E) Representative gating scheme for identification of Tregs from PBLs by flow cytometry. Live cells were gated from the total population (left), followed by identification of single cells (not shown), gating for CD4+ T cell populace (center), and gating for Tregs (CD25+, FoxP3+; right). (F) Summary of percentage of Tregs/CD4+ T cells; patients with BM had increased Tregs (* p 0.05). Peripheral monocyte PD-L1 is usually independently associated with outcome To evaluate the impact of immunosuppressive markers on clinical outcomes in patients with brain metastatic disease, Kaplan-Meier progression free and overall survival.
These data indicate a possible role for targeting of the IL-6/IL-6R pathway in the treatment of NSCLC, particularly in patients with early stage disease