生物谷报道：美国研究人员最近发现，有些癌细胞可以释放一种叫“骨桥蛋白”（osteopontin）的蛋白质，这种蛋白质会“唤醒”体内休眠的癌细胞。这一发现有助于医生了解并预防癌细胞在体内的扩散。相关论文于6月13日发表在Cell上面。
研究人员给实验鼠同时移植了两种癌细胞：一种是被称为“煽动者”（instigator）的肿瘤细胞，是科学家在实验室用可快速生长的乳腺癌细胞培养成的，另一种是生长缓慢只是偶然发生转移的俗称“回应者”的癌细胞，这种癌细胞多数时间处于休眠状态。
研究人员发现，“煽动者”肿瘤细胞的存在加速“回应者”（responder）癌细胞繁殖，使转移的癌细胞增加９倍。他们用从癌症患者体内采集的结肠癌细胞作为“回应者”细胞重复实验，获得了相似的结果。
随后的分析显示，“骨桥蛋白”是这种“煽动者”肿瘤细胞发挥作用的关键所在。研究人员于是阻止癌细胞中“骨桥蛋白”的生产，结果“煽动者”肿瘤细胞继续生长繁殖，却不再刺激“回应者”细胞。研究人员由此认为，这种蛋白质会“唤醒”体内休眠的癌细胞，帮助它们占领新组织。
在此前的研究中，研究人员一直将“骨桥蛋白”用作一种监控癌瘤生长的生物标记物，并发现这种蛋白质与包括乳腺癌和前列腺癌在内的多种癌症有直接关系。
目前，研究人员正在研发能阻止这种蛋白质发挥作用的药物，以用来对抗癌症。（生物谷www.bioon.com）
生物谷推荐原始出处：
Cell, Vol 133, 994-1005, 13 June 2008
Systemic Endocrine Instigation of Indolent Tumor Growth Requires Osteopontin
Sandra S. McAllister,1 Ann M. Gifford,1,9 Ashley L. Greiner,1,2,9 Stephen P. Kelleher,1,3 Matthew P. Saelzler,1,4 Tan A. Ince,1,5 Ferenc Reinhardt,1 Lyndsay N. Harris,6 Bonnie L. Hylander,7 Elizabeth A. Repasky,7 and Robert A. Weinberg1,4,8,
1 Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
2 The Department of Biology, Boston University, Boston, MA 02215, USA
3 Department of Biology, Williams College, Williamstown, MA 01267, USA
4 Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
5 Department of Pathology, Division of Women's and Perinatal Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
6 Department of Medical Oncology, Yale University Medical Center, New Haven, CT 06510, USA
7 Department of Immunology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
8 MIT Ludwig Center for Molecular Oncology, Cambridge, MA 02142, USA
Summary
The effects of primary tumors on the host systemic environment and resulting contributions of the host to tumor growth are poorly understood. Here, we find that human breast carcinomas instigate the growth of otherwise-indolent tumor cells, micrometastases, and human tumor surgical specimens located at distant anatomical sites. This systemic instigation is accompanied by incorporation of bone-marrow cells (BMCs) into the stroma of the distant, once-indolent tumors. We find that BMCs of hosts bearing instigating tumors are functionally activated prior to their mobilization; hence, when coinjected with indolent cells, these activated BMCs mimic the systemic effects imparted by instigating tumors. Secretion of osteopontin by instigating tumors is necessary for BMC activation and the subsequent outgrowth of the distant otherwise-indolent tumors. These results reveal that outgrowth of indolent tumors can be governed on a systemic level by endocrine factors released by certain instigating tumors, and hold important experimental and therapeutic implications.
