METHODS: Immunohistochemistry was used to evaluate the expression of M2-like TAMs and cancer stem cell (CSC) markers in 24 pairs of GBC and adjacent noncancerous tissues from patients with GBC. Subsequently, GBC cells and M2-like TAMs were co-cultured to examine the expression of CSC markers, EMT markers, and migratory behavior. Proteomics was performed on the culture supernatant of M2-like TAMs. The mechanisms underlying the induction of EMT, stemness, and metastasis in GBC by M2-like TAMs were elucidated using proteomics and transcriptomics. GBC cells were co-cultured with undifferentiated macrophages (M0) and analyzed. The therapeutic effect of gemcitabine combined with a chemokine (C-C motif) receptor 2 (CCR2) antagonist on GBC was observed in vivo.
RESULTS: The expression levels of CD68 and CD163 in M2-like TAMs and CD44 and CD133 in gallbladder cancer stem cells (GBCSCs) were increased and positively correlated in GBC tissues compared with those in neighboring noncancerous tissues. M2-like TAMs secreted a significant amount of chemotactic cytokine ligand 2 (CCL2), which activated the MEK/extracellular regulated protein kinase (ERK) pathway and enhanced SNAIL expression after binding to the receptor CCR2 on GBC cells. Activation of the ERK pathway caused nuclear translocation of ELK1, which subsequently led to increased SNAIL expression. GBCSCs mediated the recruitment and polarization of M0 into M2-like TAMs within the GBC microenvironment via CCL2 secretion. In the murine models, the combination of a CCR2 antagonist and gemcitabine efficiently inhibited the growth of subcutaneous tumors in GBC.
CONCLUSIONS: The interaction between M2-like TAMs and GBC cells is mediated by the chemokine CCL2, which activates the MEK/ERK/ELK1/SNAIL pathway in GBC cells, promoting EMT, stemness, and metastasis. A combination of a CCR2 inhibitor and gemcitabine effectively suppressed the growth of subcutaneous tumors. Consequently, our study identified promising therapeutic targets and strategies for treating GBC.
方法:免疫组织化学用于评估M2样TAMs和癌症干细胞(CSC)标志物在24对GBC患者的GBC和邻近非癌组织中的表达。随后,GBC细胞和M2样TAM共培养以检测CSC标志物的表达,EMT标记,和迁徙行为。对M2样TAM的培养上清液进行蛋白质组学研究。stemness,使用蛋白质组学和转录组学阐明了M2样TAM在GBC中的转移。将GBC细胞与未分化的巨噬细胞(M0)共培养并分析。在体内观察到吉西他滨联合趋化因子(C-C基序)受体2(CCR2)拮抗剂对GBC的治疗效果。
结果:与邻近的非癌组织相比,CD68和CD163在M2样TAMs中的表达水平以及CD44和CD133在胆囊癌干细胞(GBCSCs)中的表达水平升高,并呈正相关。M2样TAM分泌大量趋化细胞因子配体2(CCL2),与GBC细胞上的受体CCR2结合后,激活MEK/细胞外调节蛋白激酶(ERK)途径并增强SNAIL表达。ERK途径的激活导致ELK1的核易位,随后导致SNAIL表达增加。GBCSC通过CCL2分泌介导GBC微环境内M0募集和极化为M2样TAM。在鼠类模型中,CCR2拮抗剂和吉西他滨的组合有效地抑制了GBC中皮下肿瘤的生长。
结论:M2样TAM与GBC细胞之间的相互作用是由趋化因子CCL2介导的,它激活了GBC细胞中的MEK/ERK/ELK1/SNAIL通路,促进EMT,stemness,和转移。CCR2抑制剂和吉西他滨的组合有效抑制皮下肿瘤的生长。因此,我们的研究确定了治疗GBC的有希望的治疗靶点和策略.