Yamaguchi Takahisa, Fushida Sachio, Yamamoto Yasuhiko, Tsukada Tomoya, Kinoshita Jun, Oyama Katsunobu, Miyashita Tomoharu, Tajima Hidehiro, Ninomiya Itasu, Munesue Seiichi, Harashima Ai, Harada Shinichi, Yamamoto Hiroshi, Ohta Tetsuo
Department of Gastroenterologic Surgery, Division of Cancer Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa 920-8641, Japan.
Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa 920-8641, Japan.
Oncol Rep. 2017 Jun;37(6):3341-3350. doi: 10.3892/or.2017.5586. Epub 2017 Apr 19.
Tumor-associated macrophages of the M2 phenotype promote tumor proliferation and are associated with a poor prognosis in patients with various malignancies, including gastric cancer with peritoneal dissemination. The present study assessed whether paclitaxel (PTX) suppresses M2 macrophages, by acting as a Toll-like receptor 4 (TLR4) agonist. Macrophages derived from the THP-1 monocytic cell line and peripheral blood mononuclear cell (PBMC)-derived macrophages were cultured with gastric cancer cells in medium containing PTX, at a concentration that did not affect cell proliferation. The effects of PTX on macrophage expression of CD204, a marker of M2 macrophages and NOS2, a marker of M1 macrophages, was evaluated by western blotting. The ability of PTX to stimulate intranuclear translocation of NF-κB was determined by evaluating the expression of the p65 subunit of NF-κB. In THP-1 macrophages, low-dose PTX (1 and 5 nM) inhibited the expression of CD204, enhanced the expression of NOS2, and significantly suppressed the phosphorylation of Stat3, which is essential for the M2 phenotype. Low-dose PTX also inhibited CD204 expression in primary macrophages derived from PBMCs. PTX treatment of THP-1 macrophages for 1 h induced marked intranuclear translocation of NF-κB p65. Low-dose PTX inhibited the M2 phenotype and induced the M1 phenotype via TLR4 signaling, suggesting that low-dose PTX can alter the macrophage phenotype, whereas clinical doses can kill cancer cells. These results suggest that the anticancer effects of PTX are due both to its cytotoxic and immunomodulatory activities.
M2 表型的肿瘤相关巨噬细胞促进肿瘤增殖，并与包括伴有腹膜播散的胃癌在内的各种恶性肿瘤患者的不良预后相关。本研究评估了紫杉醇（PTX）是否通过作为 Toll 样受体 4（TLR4）激动剂来抑制 M2 巨噬细胞。将源自 THP-1 单核细胞系的巨噬细胞和外周血单核细胞（PBMC）衍生的巨噬细胞与胃癌细胞在含有 PTX 的培养基中培养，PTX 的浓度不影响细胞增殖。通过蛋白质印迹法评估 PTX 对 M2 巨噬细胞标志物 CD204 和 M1 巨噬细胞标志物 NOS2 的巨噬细胞表达的影响。通过评估 NF-κB 的 p65 亚基的表达来确定 PTX 刺激 NF-κB 核内转位的能力。在 THP-1 巨噬细胞中，低剂量 PTX（1 和 5 nM）抑制 CD204 的表达，增强 NOS2 的表达，并显著抑制对 M2 表型至关重要的 Stat3 的磷酸化。低剂量 PTX 还抑制了 PBMC 衍生的原代巨噬细胞中 CD204 的表达。用 PTX 处理 THP-1 巨噬细胞 1 小时可诱导 NF-κB p65 明显的核内转位。低剂量 PTX 通过 TLR4 信号传导抑制 M2 表型并诱导 M1 表型，表明低剂量 PTX 可以改变巨噬细胞表型，而临床剂量可以杀死癌细胞。这些结果表明，PTX 的抗癌作用归因于其细胞毒性和免疫调节活性。
