Tumor-associated macrophages affect breast cancer endocrine resistance through FOXM1/Wnt/ β-catenin pathway / 中华内分泌外科杂志

ABSTRACT

Objective:To explore the influence of tumor-associated macrophages (TAMs) on endocrine resistance in breast cancer through the forkhead box M1 (FOXM1) /Wnt/ β-catenin pathway. Methods:Tamoxifen-resistant breast cancer cells were cultured, THP-1 cells were induced into macrophages (MΦ), and further induced into TAMs. After being cultured in the conditioned medium (CM) of MCF-7 cells for 24 hours, MΦ were defined as MS cells. After being cultured in the CM of MCF-7R cells for 24 hours, MΦ were defined as MR cells. MCF-7 cells, after being cultured in the CM of macrophages for 24 hours, were defined as MCF-7 (MΦ) cells. MCF-7 cells, after being cultured in the CM of MS cells for 24 hours, were defined as MCF-7 (MS) cells. MCF-7 cells, after being cultured in the CM of MR cells for 24 hours, were defined as MCF-7 (MR) cells. Cell viability and invasion ability were evaluated using CCK-8 and Transwell assays. The protein levels of CD163, Wnt1, β-catenin, and FOXM1 in different groups were examined by qRT-PCR and Western blot. Results:Compared to the MS group (mRNA: 1.49±0.12, protein: 1.15±0.12), CD163 expression was higher in the MR group (mRNA: 2.33±0.16, protein 1.52±0.11) ( t=7.28, P=0.002) ( t=3.94, P=0.017), indicating that tamoxifen-resistant breast cancer cells can induce polarization of more MΦ into TAMs. TAMs increased the expression of FOXM1 in breast cancer cells, which further activated the Wnt/ β-catenin pathway. Compared to the MCF-7 (MΦ) group, the MCF-7 (MS) and MCF-7 (MR) groups showed enhanced cell viability and invasion, with the most significant increase observed in the MCF-7 (MR) group. Compared with MCF-7 (MΦ) cells, the levels of Wnt1, β-catenin, and FOXM1 in MCF-7 (MS) and MCF-7 (MR) cells were significantly increased, with the highest levels observed in the MCF-7 (MR) group with the most TAM polarization. Compared to the MCF-7 group, both the MCF-7 (MR) and MCF-7+pcDNA-FOXM1 groups showed increased levels of Wnt1 and β-catenin, enhanced cell viability and invasion. Compared to the MCF-7 (MR) group, the MCF-7 (MR) + si-FOXM1 group showed reduced levels of Wnt1 and β-catenin, weakened cell viability and invasion. Conclusion:TAMs promote endocrine resistance in breast cancer by upregulating FOXM1 and activating the Wnt/ β-catenin pathway.