Resident, School of Stomatology, Qingdao University, Qingdao City, Shandong Province, China.
Attending Doctor, School of Stomatology, Qingdao University, Qingdao City, Shandong Province, China.
J Oral Maxillofac Surg. 2022 Aug;80(8):1408-1423. doi: 10.1016/j.joms.2022.03.019. Epub 2022 Apr 15.
Tumor-associated macrophages can support oral squamous cell carcinoma (OSCC) progression, and overexpression of the immunomodulator B7H4 correlates with poor prognosis of OSCC patients. We performed this study to assess the effect of B7H4 silencing on macrophage polarization and explore the potential mechanism of B7H4 during OSCC progression.
Short hairpin RNA targeting B7H4 was used to knock down B7H4. The predictor variable was B7H4 expression level, and the outcome variables were SCC9 cell growth and metastasis, M1/M2 macrophage ratio, and anti-programmed death-1 (PD-1)/STAT3 pathway-related protein levels. These were measured through real-time qPCR, Western blot analysis, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine assay, and transwell assay. In addition, a tumor xenograft mouse model was used to examine the effect of B7H4 silencing (+/- Colivelin, an activator of STAT3) on tumor growth and macrophage polarization.
The expression of B7H4 in OSCC cell lines was more than 2-fold compared with that in human normal oral keratinocytes via real-time qPCR and Western blot analysis. Knockdown of B7H4 repressed the proliferation, migration, and invasion of SCC9 cells, which were detected by 5-ethynyl-2'-deoxyuridine and transwell assay, as well as reduced PD-1/STAT3 pathway-related protein levels, promoted M1 macrophage polarization, and inhibited M2 polarization. In vivo research demonstrated that B7H4 silencing also inhibited the growth of tumor xenograft and increased the M1/M2 ratio in an OSCC mouse model. Colivelin reversed the inhibitory effects of B7H4 knockdown on OSCC progression and reversed macrophage polarization both in vitro and in vivo.
B7H4 is upregulated during OSCC progression. Its downregulation may promote M1 macrophage polarization and inhibit M2 macrophage polarization via deactivating the PD-1/STAT3 pathway, thus restraining OSCC development.
肿瘤相关巨噬细胞可促进口腔鳞状细胞癌（OSCC）的进展，免疫调节剂 B7H4 的过表达与 OSCC 患者的预后不良相关。本研究旨在评估 B7H4 沉默对巨噬细胞极化的影响，并探讨 B7H4 在 OSCC 进展过程中的潜在机制。
使用靶向 B7H4 的短发夹 RNA 敲低 B7H4。预测变量为 B7H4 表达水平，结局变量为 SCC9 细胞生长和转移、M1/M2 巨噬细胞比例以及抗程序性死亡-1（PD-1）/STAT3 通路相关蛋白水平。通过实时 qPCR、Western blot 分析、3-(4,5-二甲基-2-噻唑基)-2,5-二苯基-2H 四唑溴盐（MTT）、5-乙炔基-2'-脱氧尿苷检测和 Transwell 检测来测量这些指标。此外，还使用肿瘤异种移植小鼠模型来研究 B7H4 沉默（+/- Colivelin，STAT3 激活剂）对肿瘤生长和巨噬细胞极化的影响。
通过实时 qPCR 和 Western blot 分析发现，B7H4 在 OSCC 细胞系中的表达是正常口腔角质形成细胞的 2 倍以上。B7H4 敲低抑制了 SCC9 细胞的增殖、迁移和侵袭，这通过 5-乙炔基-2'-脱氧尿苷和 Transwell 检测得以证实，同时还降低了 PD-1/STAT3 通路相关蛋白水平，促进了 M1 巨噬细胞极化，抑制了 M2 极化。体内研究表明，B7H4 沉默也抑制了肿瘤异种移植的生长，并增加了 OSCC 小鼠模型中的 M1/M2 比值。Colivelin 逆转了 B7H4 敲低对 OSCC 进展的抑制作用，并在体外和体内逆转了巨噬细胞极化。
B7H4 在 OSCC 进展过程中上调。其下调可能通过失活 PD-1/STAT3 通路促进 M1 巨噬细胞极化并抑制 M2 巨噬细胞极化，从而抑制 OSCC 的发展。
