Bai Yihan, Yin Kemin, Su Tong, Ji Fang, Zhang Shu
Department of Gynecology and Obstetrics, Shanghai Key Laboratory of Gynecology Oncology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
Onco Targets Ther. 2020 Jun 17;13:5743-5753. doi: 10.2147/OTT.S250520. eCollection 2020.
The infiltration of tumor-associated macrophages (TAMs) facilitates the progression of epithelial ovarian cancer (EOC). TAMs are mainly M2-like due to exposure to various factors in the tumor microenvironment. In our previous study, we reported that collagen triple helix repeat containing 1(CTHRC1), a secreted protein, is associated with ovarian cancer progression and metastasis. However, the correlation between CTHRC1 and the immunological microenvironment in EOC remains unknown.
The association with the expression of CTHRC1 and CD68CD163 TAMs infiltration density and phosphorylation of STAT6 was analyzed in tumor tissues of ovarian cancer patients by immunohistochemistry. Western blot and flow cytometry analysis were used to analyze M2-like macrophage polarization induced by CTHRC1. Cell Counting Kit-8 and adhesion assays were used to detect cell proliferation and adhesion, respectively. Cell migration and invasion were detected using transwell assays.
In the present study, we observed that the overexpression of CTHRC1 and increased TAMs infiltration density are closely correlated to an advanced stage of EOC. Meanwhile, CTHRC1 expression was positively associated with the infiltration density of M2-like CD68CD163TAMs and phosphorylation of STAT6 in EOC. In human PBMC-derived monocytes, recombinant CTHRC1 protein (rCTHRC1) induces an M2-like macrophage phenotype, in a dose-dependent manner, characterized by activating the STAT6 signaling pathway. The conditioned culture medium of Lenti-CTHRC1 EOC cells promoted M2 polarization of macrophages, and by contrast, CTHRC1 knockdown abolished STAT6-mediated M2 polarization of macrophages. Moreover, the culture supernatants of rCTHRC1-treated macrophages efficiently increased the migration and invasion abilities of ovarian cancer cells.
Our data indicate that CTHRC1 might play an important role in regulating M2 polarization of macrophages in the ovarian tumor microenvironment and suggest that it is a potential therapeutic target for antitumor immunity.
肿瘤相关巨噬细胞（TAM）的浸润促进上皮性卵巢癌（EOC）的进展。由于暴露于肿瘤微环境中的各种因素，TAM主要呈M2样。在我们之前的研究中，我们报道了一种分泌蛋白——含胶原三螺旋重复序列1（CTHRC1）与卵巢癌的进展和转移有关。然而，CTHRC1与EOC免疫微环境之间的相关性仍不清楚。
采用免疫组织化学方法分析卵巢癌患者肿瘤组织中CTHRC1表达与CD68\CD163 TAM浸润密度及STAT6磷酸化之间的相关性。采用蛋白质免疫印迹法和流式细胞术分析CTHRC1诱导的M2样巨噬细胞极化。分别采用细胞计数试剂盒-8和黏附试验检测细胞增殖和黏附。采用Transwell试验检测细胞迁移和侵袭。
在本研究中，我们观察到CTHRC1的过表达和TAM浸润密度增加与EOC的晚期密切相关。同时，CTHRC1表达与EOC中M2样CD68\CD163 TAM的浸润密度及STAT6磷酸化呈正相关。在人外周血单个核细胞来源的单核细胞中，重组CTHRC1蛋白（rCTHRC1）以剂量依赖的方式诱导M2样巨噬细胞表型，其特征是激活STAT6信号通路。慢病毒CTHRC1 EOC细胞的条件培养基促进巨噬细胞的M2极化，相反，CTHRC1基因敲低消除了STAT6介导的巨噬细胞M2极化。此外，rCTHRC1处理的巨噬细胞的培养上清液有效地提高了卵巢癌细胞的迁移和侵袭能力。
我们的数据表明，CTHRC1可能在调节卵巢肿瘤微环境中巨噬细胞的M2极化中起重要作用，并提示它是抗肿瘤免疫的潜在治疗靶点。
