Differentiation of mesenchymal stem cells into myofibroblasts under the induction of tumor microenvironment in rabbits / 中国组织工程研究

ABSTRACT

BACKGROUND:Studies have shown that mesenchymsi stem cells (MSCs) participate in tumor stroma remodeling,but the mechanism is not clear.However,myofibroblast is related with tumor strema remodeling.OBJECTIVE:To investigate whether MSCs can differentiate into myofibroblast under the induction of tumor microenvironment.DESIGN,TIME AND SETINGThis in vitro observation and in vivo transplantation cytology experiment was performed at institute of Low Temperature Medicine,Qilu Hospital of Shandong University from June 2006 to December 2007.MATERIALSTwelve male New Zealand white rabbits,with 3-month-old,were purchased from Shandong Academy of Agricultural Sciences.METHODS:MSCs were obtained through bone marrow aspirates in male New Zealand rabbits and cultured by density gradient method.The 2~(nd) passage of MSCs were labeled with DAPI,and adjusted cell density to 5×10~(10) /L.The cells were assigned into experimental and control groups.For the experimental group,the passage two MSCs were cultured in low-glucose DMEM containing 10% fetal bovine serum and 30% VX2-cultured supernatant.For the control group,passage two MSCs were cultured in low-glucose DMEM containing 10% fetal bovine serum.Also,DAPI labeled self passage 2 MSCs of avery animal were delivered uniformly via direct surgical intratumoral injection to observe the differentiation of MSCs in tumor tissue.MAIN OUTCOME MEASURES:Immunofluorescense and RT-PCR were used to test the expression of α-SMA and Vimentin in MSCs of both groups 14 days later.At 3 weeks after VX2.intratumoral injection,Immunofluorescence was used to observe the distribution and differentiation of MSCs in tumor tissue.RESULTS:After stimulated with 30% VX2-cultured supematant for 2 weeks,Cy3 immunofluorescance showed that the expressions of α-SMA and Vimentin were strongly expressed in the experimental group,which was weakly expressed in the control group.Compared to the control group,the levels of α-SMA and Vimentin mRNA were obviously increased in the experimental group (P ＜ 0.01,P ＜ 0.05).At 3 weeks after MSCs intratumoral injection,these MSCs mainly distributed in tumor stroma and the expression of α-SMA and Vimentin in MSCs were also obviously increased,which demonstrated that the MSCs had differentiated into myofibroblasts.CONCLUSIONS:Under the induction of tumor microenivironment,MSCs can differentiate into myofibroblast,accordingly,accelerate the growth of tumor.