中文摘要：

目的探讨人脐带间充质干细胞（hUCMSCs）在MCF-7B乳腺癌微环境中是否存在恶性转变并探究其生物学变化与STA33异常激活及高表达的关系。方法将hUCMSCs分为3组：空白对照组（hUCMSCs单独培养）、实验组（hUCMSCs与MCF-7B共培养）和阳性对照组（MCF-7B单独培养）。倒置显微镜观察细胞形态变化；流式细胞术检测细胞周期；RT—qPCR检测STAT3及其下游原癌基因c—Myc及抗凋亡Bcl—xLmRNA的表达；细胞免疫荧光检测p-STAT3、c—Mye和Bcl—xL蛋白表达及定位；Westernblot检测p-STAT3、STAT3、c—Myc和Bcl—xL蛋白表达。结果实验组hUCMSCs与对照组比较核质比增大，细胞大小不一，排列紊乱；实验组细胞G，期比例显著低于对照组（P〈0．05），S期和G，期比例均显著高于对照组（P〈0．05）；实验组STAT3、c—Myc和Bcl—xI。mRNA的表达均显著高于对照组（P〈0．05）；实验组p-STAT3、STA33、c—Myc和Bcl—xL的蛋白表达水平显著高于对照组（P〈0．05），且主要定位于细胞核内。结论hUCMSCs在MCF一7B乳腺癌微环境中存在恶性转化趋势，且STA33的异常激活及高表达是hUCMSCs恶性转化的重要冈素之一。

英文摘要：

Objective To investigate whether hUCMSCs undergo malignant transformation when exposed to MCF-7B breast cancer microenvironment and whether the abnormal activation and over expression of STAT3 play an impor- tant role in this transformation. Methods The experiment was divided into three groups：blank group（hUCMSCs were separately cultured）, experimental group （hUCMSCs were indirectly co-cultured with MCF-7B breast cancer cells） , positive control group （MCF-7 B breast cancer cells were separately cultured）. Morphology of cells was detec- ted by invertedmicroscope. Cell cycle was detected by flow cytometry. The mRNA expression of STAT3, c-Myc and Bcl-xL was tested by real-time PCR. The p~tein expression and location of p-STAT3,c-Myc and Bcl-xL were detected by immunofluorescence. The protein expressions of p-STAT3, STAT3, c-Myc and Bcl-xL were also meas- ured by Western blot. Results The experimental group cells showed typical morphology of the tumor cells. The cells proportion of experiment group in G1 phase was significantly lower than that of the blank group （ P 〈 0. 05 ）, but which in S and G2 phase were significantly higher than those of the blank group （ P 〈 0.05 ）. The mRNA expression levels of STAT3, c-Myc and Bcl-xL in experimental group was significantly higher than those in blank group （ P 〈 0. 05）. p-STAT3,STAT3,c-Myc and Bcl-xL protein were significantly higher than those of the blank group （P 〈 0. 05 ） , and they were mainly located in the nuclei. The protein expression of STATS also showed significant changes in experimental group. Conclusions hUCMSCs trends to malignant transformations when exposed to MCF-TB breast cancer microenvironment. The abnormal activation and over expression of STAT3 are of important factors leading to the malignant transformation of hUCMSCs.