NHC Key Laboratory of Biotechnology of Antibiotics, Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Cancer Chemother Pharmacol. 2021 Mar;87(3):425-436. doi: 10.1007/s00280-020-04209-7. Epub 2021 Jan 3.
To investigate the antitumor efficacy of pingyangmycin (PYM) in combination with anti-PD-1 antibody and determine the capability of PYM to induce immunogenic cell death (ICD) in cancer cells.
The murine 4T1 breast cancer and B16 melanoma models were used for evaluation of therapeutic efficacy of the combination of PYM with anti-PD-1 antibody. The ELISA kits were used to quantify the ICD related ATP and HMGB1 levels. The Transwell assay was conducted to determine the chemotaxis ability of THP-1 cell in vitro. The flow cytometry was used to measure reactive oxygen species level and analyze the ratio of immune cell subsets.
PYM induced ICD in murine 4T1 breast cancer and B16 melanoma cells and increased the release of nucleic acid fragments that may further promote the monocytic chemotaxis. In the 4T1 murine breast cancer model, PYM alone, anti-PD-1 antibody alone, and their combination suppressed tumor growth by 66.3%, 16.1% and 77.6%, respectively. PYM markedly enhanced the therapeutic efficacy of anti-PD-1 antibody against 4T1 breast cancer. The calculated CDI (coefficient of drug interaction) indicated synergistic effect. Evaluated by graphic analysis, the nucleated cells intensity in the femur bone marrow remained unchanged. Histopathological observations revealed no noticeable toxico-pathological changes in the lung and various organs, indicating that the PYM and anti-PD-1 antibody combination exerted enhanced efficacy at well-tolerated dosage level. By the combination treatment, a panel of immunological changes emerged. The ratio of CD3 cells, NK cells and NKT cells increased and Tregs decreased in peripheral blood. The DCs increased in the spleen. Prominent changes occurred in tumor infiltrating lymphocytes. The ratio of CD8 cells increased, while that of CD4 cells decreased; however, the ratio of CD3 cells remained unchanged, implying that certain immunological responses emerged in the tumor microenvironment. PYM alone could also increase CD8 cells and reduce CD4 cells in tumor infiltrating lymphocytes.
The studies indicate that PYM, as an ICD inducer with mild myelosuppression effect, may enhance the therapeutic efficacy of anti-PD-1 antibody in association with tumor infiltrating CD8 T cell augmentation.
研究平阳霉素（PYM）联合抗 PD-1 抗体的抗肿瘤疗效，并确定 PYM 诱导癌细胞免疫原性细胞死亡（ICD）的能力。
采用小鼠 4T1 乳腺癌和 B16 黑色素瘤模型评价 PYM 联合抗 PD-1 抗体的治疗效果。ELISA 试剂盒用于定量测定 ICD 相关的 ATP 和 HMGB1 水平。Transwell 实验测定体外 THP-1 细胞的趋化能力。流式细胞术测定活性氧水平，并分析免疫细胞亚群比例。
PYM 诱导小鼠 4T1 乳腺癌和 B16 黑色素瘤细胞发生 ICD，并增加核酸片段的释放，可能进一步促进单核细胞趋化。在 4T1 小鼠乳腺癌模型中，PYM 单药、抗 PD-1 抗体单药和联合治疗分别抑制肿瘤生长 66.3%、16.1%和 77.6%。PYM 显著增强了抗 PD-1 抗体对 4T1 乳腺癌的治疗效果。计算得到的药物相互作用系数（CDI）提示协同作用。通过图形分析评估，股骨骨髓中的有核细胞强度保持不变。组织病理学观察未发现肺和各种器官有明显的毒性病理学变化，表明 PYM 与抗 PD-1 抗体联合在可耐受的剂量水平发挥增强疗效的作用。联合治疗后出现了一系列免疫变化。外周血中 CD3 细胞、NK 细胞和 NKT 细胞的比例增加，Tregs 减少，脾中 DC 增加。肿瘤浸润淋巴细胞发生显著变化。CD8 细胞比例增加，而 CD4 细胞比例降低；然而，CD3 细胞比例保持不变，提示肿瘤微环境中出现了某些免疫反应。PYM 单药也可增加肿瘤浸润淋巴细胞中的 CD8 细胞并减少 CD4 细胞。
研究表明，PYM 作为一种具有轻度骨髓抑制作用的 ICD 诱导剂，可能通过增强肿瘤浸润 CD8 T 细胞的扩增来增强抗 PD-1 抗体的治疗效果。
