本研究旨在调查间充质干细胞衍生的细胞外囊泡（MSC-EVs）对被认为包含有限CSC群体的人MCF7乳腺癌细胞增殖的影响，并研究其与OCT4和ALDH1干性标记物表达的相关性。使用尺寸排除色谱法成功从脐带MSC的培养基中分离出EVs。通过透射电子显微镜（TEM）对分离的EVs分数进行了验证。然后将5％和10％（v/v）浓度的MSC-EVs与MCF7细胞共培养。为了研究MCF7细胞对MSC-EVs的摄取，我们进行了共聚焦显微镜分析。随后，使用尝试蓝排除实验确定了共培养的MCF7细胞的增殖，使用定量逆转录聚合酶链式反应、Western Blot和Aldefluor™测定了其OCT4 mRNA和蛋白质表达，以及作为干性特征标记物的ALDH活性。MSC-EVs在TEM下被检测为圆形约100 nm大小的颗粒。我们还证明MSC-EVs可以被MCF7细胞内化。值得注意的是，5％浓度的MSC-EVs增加了MCF7细胞中OCT4 mRNA的表达和ALDH1活性。而10％浓度的MSC-EVs降低了OCT4表达和ALDH1活性。MSC衍生的EVs以浓度依赖的方式调节MCF7细胞的干性，包括OCT4表达和ALDH1活性，与细胞增殖增加相对应。

The aim of this study was to investigate the effect of mesenchymal stem cells-derived extracellular vesicles (MSC-EVs) on the human MCF7 breast cancer cell proliferation that have been considered to contain limited CSC population and its association with the expression of OCT4 and ALDH1 stemness markers.EVs were successfully isolated from the conditioned medium of umbilical cord MSCs using size exclusion chromatography. The isolated EV fraction was verified under a transmission electron microscope (TEM). Five and ten percent (v/v) concentration of MSC-EVs were then co-cultured with MCF7 cells. To investigate MSC-EV uptake by MCF7 cells, we performed confocal microscopy analysis. Subsequently, the proliferation of co-cultured MCF7 cells was determined using trypan blue exclusion assay, while their mRNA and protein expression of OCT4 as well as ALDH activity as the marker of stemness properties were analyzed using quantitative reverse transcription polymerase chain reaction, Western Blot, and Aldefluor™ assays, respectively.MSC-EVs were detected as round-shaped, ~100 nm sized particles under TEM. We also demonstrate that MSC-EVs can be internalized by MCF7 cells. Notably, MSC-EVs of 5% concentration increased OCT4 mRNA expression and ALDH1 activity in MCF7 cells. At 10% concentration, MSC-EVs reduced the OCT4 expression and ALDH1 activity.MSC-derived EVs modulate the stemness of MCF7 cells, either OCT4 expression or ALDH1 activity, in a concentration dependent manner along with the increase of cell proliferation.