乳腺癌是女性中最常见的癌症形式。癌症肿瘤的微环境被各种细胞包围，包括微生物群。微生物与其宿主之间的不平衡可能会导致乳腺癌的发生和扩散。因此，本研究的目的是研究粪肠球菌对乳腺癌细胞系（MCF-7）的影响，以模拟乳腺癌的管腔A亚型，使用非靶向蛋白质组学方法分析乳腺癌细胞的蛋白质组谱在接受粪肠球菌治疗后，为了了解微生物组及其在癌症发展中的作用。培养乳腺癌细胞系 MCF-7，然后在 37°C、5% CO2 的加湿培养箱中在两个时间点（24 小时和 48 小时）用 10% 细菌上清液处理。然后使用二维差异 (2D-DIGE) 凝胶电泳提取和分离蛋白质，并通过基质辅助激光解吸/电离时间鉴定具有统计学意义的蛋白质（p 值 < 0.05，倍数变化 > 1.5）。 -飞行质谱（MALDI-TOF-MS）。与对照组相比，粪肠球菌处理 24 和 48 小时的细胞中的蛋白质指纹显示出差异的蛋白质表达模式。我们发现受粪肠球菌影响的 MCF-7 乳腺癌细胞中有 58 个具有统计学意义的蛋白质变化。 Kilin 和 transgelin 在治疗 24 小时后表达上调，可用作乳腺癌的诊断和预后标志物。此外，另一种参与抑制细胞增殖的蛋白质是含有卷曲螺旋结构域的蛋白质154。本研究中鉴定的蛋白质标记物可以作为乳腺癌进展的可能生物标记物。这促进了它们未来作为癌症治疗和诊断中的重要治疗目标的使用，并增加了我们对乳腺微生物组及其在癌症发展中的作用的了解。

Breast cancer is the most prevalent form of cancer among women. The microenvironment of a cancer tumor is surrounded by various cells, including the microbiota. An imbalance between microbes and their host may contribute to the development and spread of breast cancer. Therefore, the objective of this study is to investigate the influence of Enterococcus faecalis on a breast cancer cell line (MCF-7) to mimic the luminal A subtype of breast cancer, using an untargeted proteomics approach to analyze the proteomic profiles of breast cancer cells after their treatment with E. faecalis in order to understand the microbiome and its role in the development of cancer. The breast cancer cell line MCF-7 was cultured and then treated with a 10% bacterial supernatant at two time points (24 h and 48 h) at 37 °C in a humidified incubator with 5% CO2. Proteins were then extracted and separated using two-dimensional difference (2D-DIGE) gel electrophoresis, and the statistically significant proteins (p-value < 0.05, fold change > 1.5) were identified via matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS). The protein fingerprints showed a differential protein expression pattern in the cells treated with E. faecalis for 24 and 48 h compared with the control. We found 58 statistically significant proteins changes in the MCF-7 breast cancer cells affected by E. faecalis. Kilin and transgelin were upregulated after 24 h of treatment and could be used as diagnostic and prognostic markers for breast cancer. In addition, another protein involved in the inhibition of cell proliferation was coiled-coil domain-containing protein 154. The protein markers identified in this study may serve as possible biomarkers for breast cancer progression. This promotes their future uses as important therapeutic goals in the treatment and diagnosis of cancer and increases our understanding of the breast microbiome and its role in the development of cancer.