Zhao Hai-Feng, Chen Jun, Xu Zhi-Shun, Zhang Ke-Qin
Department of Urology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China.
Chin Med J (Engl). 2009 Mar 20;122(6):712-5.
Tumor has an ability to become enriched in mesenchymal stem cells (MSCs) and of guiding MSCs to migrate to tumor tissue. But there are lack of relevant reports on the distribution and differentiation of MSCs in tumor tissue and the effect on tumor growth after MSCs engrafted in tumor tissue. In this study, we observed the distribution of bone marrow MSCs in tumor tissue and the possibility of MSCs differentiating into myofibroblast under the induction of local tumor microenvironment.
Twenty-four New Zealand rabbits were randomly classified into the control group and the test group. MSCs were isolated and cultured for each animal. vx-2 tumor tissue was transplanted under the bladder mucosa of each animal. One week after the transplantation, the self F2 passage MSCs marked by 4', 6-diamidino-2-phenylindole were transplanted into tumor tissue in the test group while only Dulbecco's modified Eagle's medium-low glucose was infused into the control group. Ultrasonography was performed for each animal 1, 2, 3 and 4 week (s) after the vx-2 tumor mass was transplanted. The maximum bladder tumor diameter of each animal was recorded and the mean value of each group was calculated. One animal from each group was sacrificed in the third week and the remaining animals in the fourth week to observe the tumor development. Another animal treated the same as the test group was sacrificed to observe the distribution of MSCs in tumor tissue one week after self MSCs transplantation. Immunofluorescence was used to trace MSCs in tumor tissue. The double labeling immunofluorescence for alpha-smooth muscle actin (alpha-SMA) and vimentin was performed to identify whether the MSCs can differentiate into myofibroblast.
The ultrasonography showed no tumor mass one week after the vx-2 tumor mass transplantation. The mean maximum tumor diameter of the control group and test group was (0.70 +/- 0.14) cm and (0.78 +/- 0.14) cm, respectively, and there was no significant difference (t = 1.308, P = 0.204). The tumor growth rate of the test group increased gradually in the third and fourth weeks, and the difference of the mean maximum tumor diameter between the two groups also increased gradually and was statistically significant (P < 0.05). MSCs distributed uniformly in tumor tissue one week after transplantation while most were distributed in the tumor stroma three weeks after transplantation. The double labeling immunofluorescence showed that the expression of alpha-SMA as well as Vimentin increased significantly three weeks after mesenchymal stem cells engrafted into tumor, indicating that MSCs had differentiated into myofibroblasts under the induction of the tumor microenvironment.
MSCs can accelerate the tumor development and can differentiate into myofibroblast under the induction of tumor microenvironment.
肿瘤具有富集间充质干细胞（MSCs）以及引导MSCs迁移至肿瘤组织的能力。但关于MSCs在肿瘤组织中的分布与分化以及MSCs植入肿瘤组织后对肿瘤生长的影响，目前缺乏相关报道。在本研究中，我们观察了骨髓MSCs在肿瘤组织中的分布情况以及在局部肿瘤微环境诱导下MSCs分化为肌成纤维细胞的可能性。
将24只新西兰兔随机分为对照组和试验组。为每只动物分离并培养MSCs。将VX-2肿瘤组织移植到每只动物的膀胱黏膜下。移植1周后，将经4',6-二脒基-2-苯基吲哚标记的第2代自体MSCs移植到试验组的肿瘤组织中，而对照组仅注入杜氏改良Eagle培养基 - 低糖培养基。在移植VX-2肿瘤块后1、2、3和4周对每只动物进行超声检查。记录每只动物膀胱肿瘤的最大直径，并计算每组的平均值。在第3周每组处死1只动物，第4周处死其余动物以观察肿瘤发展情况。处死另一只与试验组处理相同的动物，以观察自体MSCs移植1周后MSCs在肿瘤组织中的分布情况。采用免疫荧光法追踪肿瘤组织中的MSCs。进行α-平滑肌肌动蛋白（α-SMA）和波形蛋白的双重标记免疫荧光，以鉴定MSCs是否能分化为肌成纤维细胞。
VX-2肿瘤块移植1周后超声检查未发现肿瘤块。对照组和试验组的平均最大肿瘤直径分别为（0.70±0.14）cm和（0.78±0.14）cm，差异无统计学意义（t = 1.308，P = 0.204）。试验组的肿瘤生长速率在第3周和第4周逐渐增加，两组平均最大肿瘤直径的差异也逐渐增大且具有统计学意义（P < 0.05）。移植1周后MSCs在肿瘤组织中分布均匀，而移植3周后大部分分布在肿瘤基质中。双重标记免疫荧光显示，间充质干细胞植入肿瘤3周后，α-SMA以及波形蛋白的表达显著增加，表明MSCs在肿瘤微环境的诱导下已分化为肌成纤维细胞。
MSCs可加速肿瘤发展，并在肿瘤微环境的诱导下分化为肌成纤维细胞。
