Biological Significance of Isolated Tumor Cells and Micrometastasis in Lymph Nodes Evaluated Using a Green Fluorescent Protein–Tagged Human Gastric Cancer Cell Line
Biological Significance of Isolated Tumor Cells and Micrometastasis in Lymph Nodes Evaluated Using a Green Fluorescent Protein–Tagged Human Gastric Cancer Cell Line
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DOI：
10.1158/1078-0432.ccr-05-1963
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发表时间：
2006-01
影响因子：
11.5
通讯作者：
H. Yokoyama;H. Nakanishi;Y. Kodera;Y. Ikehara;N. Ohashi;Yuichi Ito;M. Koike;M. Fujiwara;M. Tatematsu;A. Nakao
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文献类型：
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作者：
H. Yokoyama;H. Nakanishi;Y. Kodera;Y. Ikehara;N. Ohashi;Yuichi Ito;M. Koike;M. Fujiwara;M. Tatematsu;A. Nakao
目的：由于缺乏合适的动物模型，国际抗癌联合会定义的淋巴结中分离的肿瘤细胞和微转移的生物学意义基本上仍然未知。在本研究中，我们开发了一种淋巴结微转移模型，其特征在于标记有绿色荧光蛋白基因（GCIY-EGFP）的人胃癌细胞系，该模型允许可视化甚至分离的肿瘤细胞在转移的发展中而无需组织学程序。利用这个模型，我们研究了手术和化疗对淋巴结早期转移形成的影响。实验设计：s.c.用荧光解剖显微镜检查GCIY-EGFP细胞接种到裸鼠中。然后，检查手术切除原发性肿瘤，有或没有抗去唾液酸GM 1治疗或术后化疗对分离的肿瘤细胞的生长和淋巴结中的微转移的影响。结果如下：发现GCIY-EGFP细胞自发转移到腹股沟淋巴结，形成孤立的肿瘤细胞，微转移，最后，在注射后1至2周，3至5周，和5周分别发展为肉眼可见的转移。当在接种后2周内切除原发性肿瘤时，在所有检查的小鼠中（5/5），淋巴结中的分离的肿瘤细胞（但不是微转移）在手术后4周消退。抗脱唾液酸GM 1治疗可以完全逆转分离的肿瘤细胞的自发消退，这可以有效地耗尽裸小鼠中的自然杀伤细胞。在早期阶段切除原发肿瘤后的化疗部分消除了淋巴结中剩余的微转移。结论：这些结果表明，孤立的肿瘤细胞在区域淋巴结消退的原发性肿瘤切除主要是通过自然杀伤细胞介导的抗肿瘤活性和淋巴结中的微转移，可以有效地消除术后化疗。
Purpose: The biological significance of isolated tumor cells and micrometastasis in lymph node defined by the International Union against Cancer remains essentially unknown because of the lack of appropriate animal models. In the present study, we developed a lymph node micrometastasis model featuring a human gastric cancer cell line tagged with green fluorescent protein gene (GCIY-EGFP), which allows visualization of even isolated tumor cells in the development of metastasis without histologic procedure. Using this model, we investigated the effect of surgery and chemotherapy on the growth of early-phase metastasis formation in the lymph nodes. Experimental Design: The time course of spontaneous inguinal lymph node metastasis after s.c. inoculation of GCIY-EGFP cells into nude mice was examined with fluorescence dissecting microscopy. Then, the effects of surgical removal of the primary tumor with or without anti-asialo GM1 treatment or postoperative chemotherapy on the growth of isolated tumor cells and micrometastasis in the lymph nodes were examined. Results: GCIY-EGFP cells were found to metastasize spontaneously to the inguinal lymph nodes to form isolated tumor cells, micrometastasis, and, finally, develop macroscopic metastasis at 1 to 2, 3 to 5, and 5 weeks postinjection, respectively. When the primary tumors were removed within 2 weeks of inoculation, isolated tumor cells, but not micrometastasis, in the lymph nodes regressed by 4 weeks after surgery in all the mice examined (five of five). This spontaneous regression of isolated tumor cells was completely reversed by anti-asialo GM1 treatment, which could deplete natural killer cells effectively in nude mice. Chemotherapy following resection of the primary tumor at an early stage partially eliminated the remaining micrometastasis in the lymph nodes. Conclusions: These results suggest that isolated tumor cells in the regional lymph nodes regressed by removal of the primary tumor mainly via natural killer cell–mediated antitumor activity and that micrometastasis in the lymph nodes could be effectively eliminated by the postoperative chemotherapy.