胃癌微环境中M2亚型巨噬细胞对胃癌间充质干细胞促肿瘤作用的影响

The influence of M2 macrophages on tumor-promoting effect of gastric cancer-derived mesenchymal stem cells in gastric cancer microenvironment

目的探讨胃癌微环境中M2亚型巨噬细胞对人胃癌间质干细胞(GC-MSCs)发挥促胃癌作用的影响。方法采用氯磷酸盐脂质体清除BALB/c裸鼠体内巨噬细胞,观察并记录巨噬细胞清除前后GC-MSCs与胃癌细胞共注射组裸鼠的肿瘤体积和质量。收集各组裸鼠及胃癌患者肿瘤组织,反转录PCR(RT-PCR)和蛋白质印迹法(Western blot)分别检测M2亚型相关基因转录及蛋白表达情况。体外共培养实验验证GCMSCs对巨噬细胞极化的调节作用。结果体内巨噬细胞清除可明显抑制GC-MSCs共注射组肿瘤的生长(P=0.009)。此外,GC-MSCs共注射组裸鼠及胃癌患者肿瘤组织中M2亚型巨噬细胞相关蛋白的转录与表达水平均明显高于对照组或对应癌旁组织。与GC-MSCs直接接触培养72h后,THP-1来源人巨噬细胞中M2亚型巨噬细胞相关蛋白表达明显上调。结论胃癌微环境中M2亚型巨噬细胞在GC-MSCs的促胃癌效应中发挥关键作用。

Objective To investigate the effect of M2 macrophages resident in gastric cancer microenvironment on the tumor-promoting effect of human gastric cancer-derived mesenchymal stem cells（GC-MSCs）.Methods Macrophages in BALB/c mice were depleted by using clodronate liposomes.The tumor volumes and weights in nude mice co-injected with GC-MSCs and BGC-823 with and without macrophage depletion were recorded.Tumor tissues of nude mice and gastric cancer patients were collected,and M2 macrophage-associated genes and proteins were detected by RT-PCR and western blot.Furthermore,the regulating effect of GCMSCs on macrophage polarization to M2-subtype was validated in the co-culture experiment in vitro.ResultsTumor growth in GC-MSCs co-injected mice was significantly inhibited by macrophage depletion（P=0.009）.Results of RT-PCR and western blot showed that the transcription and expression of M2 macrophage-associated proteins were significantly higher in tumor tissues from GC-MSCs co-injected mice than those in the control group.Moreover,the transcription and expression levels of M2 macrophage-associated proteins were also higher in gastric cancer tissues than those in the corresponding adjacent normal tissues.After co-culture with GCMSCs directly,the expressions of M2 macrophage-associated proteins were significantly up-regulated in THP-1-derived macrophages.Conclusion M2 macrophages in gastric cancer microenvironment might play a critical role in the tumor-promoting effect of GC-MSCs.