乳腺癌细胞分泌的血管内皮生长因子在小鼠肺部前转移生态位的形成中起关键作用。

[Vascular endothelial growth factor secreted by breast cancer cells plays a critical role in the formation of pre-metastatic niche in the mouse lung].

作者信息

Li Ranran, Yuan Bing, Zhang Ying, Dai Jianjian, Zhang Pengfei, Fang Feifei, Han Mingyong

机构信息

Cancer Therapy and Research Center, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China.

出版信息

Zhonghua Zhong Liu Za Zhi. 2016 Jan;38(1):17-22. doi: 10.3760/cma.j.issn.0253-3766.2016.01.004.

DOI:10.3760/cma.j.issn.0253-3766.2016.01.004

PMID:26796801

Abstract

OBJECTIVE

To explore the formation of pre-metastatic niche in the mouse lung and to study the underlying molecular mechanisms whereby primary breast carcinoma-derived factors mediate recruitment of bone marrow-derived cells (BMDCs) and affect the formation of pre-metastatic lung environment before the arrival of tumor cells.

METHODS

Mammary carcinoma 4T1 cells were inoculated into the mammary gland to construct mouse model of breast cancer. Confocal microscopy was used to detect the recruitment of BMDCs in the pre-metastatic lungs. The expression of factors in the mouse sera and 4T1 cell culture media was assayed using RayBio Custom mouse cytokine antibody array kit. The mice were injected daily with recombinant VEGF for 7 consecutive days to observe the effect of VEGF on BMDCs recruitment in the mouse lung.

RESULTS

No BMDCs were observed in the lungs of control and 4T1-tumor-bearing mice on day 0. On day 7 and 14, clusters of BMDCs observed in the lungs of 4T1-tumor-bearing mice were 8.7±2.2/objective field and 48.8±3.2/objective field, respectively, significantly higher than those in the control mice (1.1±0.8/objective field and 3.1±1.7/objective field) (P<0.05 for both). Confocal microscopic observation found that metastatic breast cancer cells preferentially facilitate BMDCs recruitment sites in the pre-metastatic mouse lungs. The levels of VEGF, GM-CSF, and IL-6 in the serum of 4T1-tumor-bearing mice were significantly increased compared with those in the control group (P<0.05 for all). However, VEGF was detected only in the culture media of 4T1 cells. The amount of BMDCs in the mouse lung tissue was (22.8±3.6)/objective field in the VEGF group and (3.1±0.4)/objective field in the control group (P<0.05). There were 36.8±5.4 metastatic foci in the lung tissue of VEGF group and 12.6±2.2 in the control group (P<0.05).

CONCLUSIONS

The results of this study demonstrate that primary breast cancer cells can alter the lung microenvironment during the pre-metastatic phase and induce the formation of pre-metastatic niche. Primary tumor cell-derived VEGF may be a crucial factor responsible for the formation of pre-metastatic niche.

摘要

目的

探讨小鼠肺脏中前转移生态位的形成，并研究原发性乳腺癌衍生因子介导骨髓来源细胞（BMDCs）募集以及在肿瘤细胞到达之前影响前转移肺环境形成的潜在分子机制。

方法

将乳腺癌4T1细胞接种到乳腺中构建乳腺癌小鼠模型。采用共聚焦显微镜检测前转移肺中BMDCs的募集情况。使用RayBio定制小鼠细胞因子抗体阵列试剂盒检测小鼠血清和4T1细胞培养基中因子的表达。连续7天每天给小鼠注射重组VEGF，观察VEGF对小鼠肺中BMDCs募集的影响。

结果

在第0天，对照小鼠和荷4T1肿瘤小鼠的肺中均未观察到BMDCs。在第7天和第14天，荷4T1肿瘤小鼠肺中观察到的BMDCs簇分别为8.7±2.2/视野和48.8±3.2/视野，显著高于对照小鼠（1.1±0.8/视野和3.1±1.7/视野）（两者P均<0.05）。共聚焦显微镜观察发现，转移性乳腺癌细胞优先促进前转移小鼠肺中BMDCs的募集位点。荷4T1肿瘤小鼠血清中VEGF、GM-CSF和IL-6水平与对照组相比显著升高（均P<0.05）。然而，仅在4T1细胞的培养基中检测到VEGF。VEGF组小鼠肺组织中BMDCs数量为（22.8±3.6）/视野，对照组为（3.1±0.4）/视野（P<0.05）。VEGF组肺组织中转移灶为36.8±5.4个，对照组为12.6±2.2个（P<0.05）。