Docetaxel Upregulates HMGB1 Levels in Non-small Cell Lung Cancer

Immune checkpoint inhibitors (ICIs) exert beneficial effects in non-small cell lung cancer (NSCLC) patients. However, ICIs are only advantageous for a limited population of NSCLC patients. Therefore to enhance their effects, combination therapies with ICIs have been developed. To identify preferable chemotherapy to combine with ICIs against lung cancer, we examined immunological effects of docetaxel compared with epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI). We found no difference in peripheral lymphocyte counts and ratio of their subpopulations in lung cancer patients before and after both treatments. On the other hand, plasma levels of high-mobility group box 1 (HMGB1), a damage-associated molecular pattern (DAMP) protein, showed significant increase after docetaxel treatment. Furthermore, we investigated effects of HMGB1 on tumor-infiltrating immune cells obtained from surgically resected tumor tissue from NSCLC patients. When the tumor infiltrating cells were stimulated with HMGBI, CD11c(+) cells showed increased expression of activation markers. These findings imply that docetaxel could be involved in anti-tumor immunity via HMGB1. Therefore docetaxel might be a candidate for combination treatment with ICIs.